1 PROC(4)                 File Formats and Configurations                PROC(4)
   2 
   3 
   4 
   5 NAME
   6        proc - /proc, the process file system
   7 
   8 DESCRIPTION
   9        /proc is a file system that provides access to the state of each
  10        process and light-weight process (lwp) in the system. The name of each
  11        entry in the /proc directory is a decimal number corresponding to a
  12        process-ID. These entries are themselves subdirectories. Access to
  13        process state is provided by additional files contained within each
  14        subdirectory; the hierarchy is described more completely below. In this
  15        document, ``/proc file'' refers to a non-directory file within the
  16        hierarchy rooted at /proc. The owner of each /proc file and
  17        subdirectory is determined by the user-ID of the process.
  18 
  19 
  20        /proc can be mounted on any mount point, in addition to the standard
  21        /proc mount point, and can be mounted several places at once. Such
  22        additional mounts are allowed in order to facilitate the confinement of
  23        processes to subtrees of the file system via chroot(1M) and yet allow
  24        such processes access to commands like ps(1).
  25 
  26 
  27        Standard system calls are used to access /proc files: open(2),
  28        close(2), read(2), and write(2) (including readv(2), writev(2),
  29        pread(2), and pwrite(2)). Most files describe process state and can
  30        only be opened for reading. ctl and lwpctl (control) files permit
  31        manipulation of process state and can only be opened for writing. as
  32        (address space) files contain the image of the running process and can
  33        be opened for both reading and writing. An open for writing allows
  34        process control; a read-only open allows inspection but not control. In
  35        this document, we refer to the process as open for reading or writing
  36        if any of its associated /proc files is open for reading or writing.
  37 
  38 
  39        In general, more than one process can open the same /proc file at the
  40        same time. Exclusive open is an advisory mechanism provided to allow
  41        controlling processes to avoid collisions with each other. A process
  42        can obtain exclusive control of a target process, with respect to other
  43        cooperating processes, if it successfully opens any /proc file in the
  44        target process for writing (the as or ctl files, or the lwpctl file of
  45        any lwp) while specifying O_EXCL in the open(2). Such an open will fail
  46        if the target process is already open for writing (that is, if an as,
  47        ctl, or lwpctl file is already open for writing). There can be any
  48        number of concurrent read-only opens; O_EXCL is ignored on opens for
  49        reading. It is recommended that the first open for writing by a
  50        controlling process use the O_EXCL flag; multiple controlling processes
  51        usually result in chaos.
  52 
  53 
  54        If a process opens one of its own /proc files for writing, the open
  55        succeeds regardless of O_EXCL and regardless of whether some other
  56        process has the process open for writing. Self-opens do not count when
  57        another process attempts an exclusive open. (A process cannot exclude a
  58        debugger by opening itself for writing and the application of a
  59        debugger cannot prevent a process from opening itself.) All self-opens
  60        for writing are forced to be close-on-exec (see the F_SETFD operation
  61        of fcntl(2)).
  62 
  63 
  64        Data may be transferred from or to any locations in the address space
  65        of the traced process by applying lseek(2) to position the as file at
  66        the virtual address of interest followed by read(2) or write(2) (or by
  67        using pread(2) or pwrite(2) for the combined operation). The address-
  68        map files /proc/pid/map and /proc/pid/xmap can be read to determine the
  69        accessible areas (mappings) of the address space. I/O transfers may
  70        span contiguous mappings. An I/O request extending into an unmapped
  71        area is truncated at the boundary. A write request beginning at an
  72        unmapped virtual address fails with EIO; a read request beginning at an
  73        unmapped virtual address returns zero (an end-of-file indication).
  74 
  75 
  76        Information and control operations are provided through additional
  77        files.  <procfs.h> contains definitions of data structures and message
  78        formats used with these files. Some of these definitions involve the
  79        use of sets of flags. The set types sigset_t, fltset_t, and sysset_t
  80        correspond, respectively, to signal, fault, and system call
  81        enumerations defined in <sys/signal.h>, <sys/fault.h>, and
  82        <sys/syscall.h>.   Each set type is large enough to hold flags for its
  83        own enumeration. Although they are of different sizes, they have a
  84        common structure and can be manipulated by these macros:
  85 
  86          prfillset(&set);         /* turn on all flags in set */
  87          premptyset(&set);        /* turn off all flags in set */
  88          praddset(&set,     flag);        /* turn on the specified flag */
  89          prdelset(&set,     flag);        /* turn off the specified flag */
  90          r = prismember(&set, flag);  /* != 0 iff flag is turned on */
  91 
  92 
  93 
  94        One of prfillset() or premptyset() must be used to initialize set
  95        before it is used in any other operation. flag must be a member of the
  96        enumeration corresponding to set.
  97 
  98 
  99        Every process contains at least one light-weight process, or lwp.  Each
 100        lwp represents a flow of execution that is independently scheduled by
 101        the operating system. All lwps in a process share its address space as
 102        well as many other attributes. Through the use of lwpctl and ctl files
 103        as described below, it is possible to affect individual lwps in a
 104        process or to affect all of them at once, depending on the operation.
 105 
 106 
 107        When the process has more than one lwp, a representative lwp is chosen
 108        by the system for certain process status files and control operations.
 109        The representative lwp is a stopped lwp only if all of the process's
 110        lwps are stopped; is stopped on an event of interest only if all of the
 111        lwps are so stopped (excluding PR_SUSPENDED lwps); is in a PR_REQUESTED
 112        stop only if there are no other events of interest to be found; or,
 113        failing everything else, is in a PR_SUSPENDED stop (implying that the
 114        process is deadlocked). See the description of the status file for
 115        definitions of stopped states. See the PCSTOP control operation for the
 116        definition of ``event of interest''.
 117 
 118 
 119        The representative lwp remains fixed (it will be chosen again on the
 120        next operation) as long as all of the lwps are stopped on events of
 121        interest or are in a PR_SUSPENDED stop and the PCRUN control operation
 122        is not applied to any of them.
 123 
 124 
 125        When applied to the process control file, every /proc control operation
 126        that must act on an lwp uses the same algorithm to choose which lwp to
 127        act upon. Together with synchronous stopping (see PCSET), this enables
 128        a debugger to control a multiple-lwp process using only the process-
 129        level status and control files if it so chooses. More fine-grained
 130        control can be achieved using the lwp-specific files.
 131 
 132 
 133        The system supports two process data models, the traditional 32-bit
 134        data model in which ints, longs and pointers are all 32 bits wide (the
 135        ILP32 data model), and on some platforms the 64-bit data model in which
 136        longs and pointers, but not ints, are 64 bits in width (the LP64 data
 137        model). In the LP64 data model some system data types, notably size_t,
 138        off_t, time_t and dev_t, grow from 32 bits to 64 bits as well.
 139 
 140 
 141        The /proc interfaces described here are available to both 32-bit and
 142        64-bit controlling processes. However, many operations attempted by a
 143        32-bit controlling process on a 64-bit target process will fail with
 144        EOVERFLOW because the address space range of a 32-bit process cannot
 145        encompass a 64-bit process or because the data in some 64-bit system
 146        data type cannot be compressed to fit into the corresponding 32-bit
 147        type without loss of information. Operations that fail in this
 148        circumstance include reading and writing the address space, reading the
 149        address-map files, and setting the target process's registers. There is
 150        no restriction on operations applied by a 64-bit process to either a
 151        32-bit or a 64-bit target processes.
 152 
 153 
 154        The format of the contents of any /proc file depends on the data model
 155        of the observer (the controlling process), not on the data model of the
 156        target process. A 64-bit debugger does not have to translate the
 157        information it reads from a /proc file for a 32-bit process from 32-bit
 158        format to 64-bit format. However, it usually has to be aware of the
 159        data model of the target process. The pr_dmodel field of the status
 160        files indicates the target process's data model.
 161 
 162 
 163        To help deal with system data structures that are read from 32-bit
 164        processes, a 64-bit controlling program can be compiled with the C
 165        preprocessor symbol _SYSCALL32 defined before system header files are
 166        included. This makes explicit 32-bit fixed-width data structures (like
 167        cstruct stat32) visible to the 64-bit program. See types32.h(3HEAD).
 168 
 169 DIRECTORY STRUCTURE
 170        At the top level, the directory /proc contains entries each of which
 171        names an existing process in the system. These entries are themselves
 172        directories. Except where otherwise noted, the files described below
 173        can be opened for reading only. In addition, if a process becomes a
 174        zombie (one that has exited but whose parent has not yet performed a
 175        wait(3C) upon it), most of its associated /proc files disappear from
 176        the hierarchy; subsequent attempts to open them, or to read or write
 177        files opened before the process exited, will elicit the error ENOENT.
 178 
 179 
 180        Although process state and consequently the contents of /proc files can
 181        change from instant to instant, a single read(2) of a /proc file is
 182        guaranteed to return a sane representation of state; that is, the read
 183        will be atomic with respect to the state of the process. No such
 184        guarantee applies to successive reads applied to a /proc file for a
 185        running process. In addition, atomicity is not guaranteed for I/O
 186        applied to the as (address-space) file for a running process or for a
 187        process whose address space contains memory shared by another running
 188        process.
 189 
 190 
 191        A number of structure definitions are used to describe the files. These
 192        structures may grow by the addition of elements at the end in future
 193        releases of the system and it is not legitimate for a program to assume
 194        that they will not.
 195 
 196 STRUCTURE OF /proc/pid
 197        A given directory /proc/pid contains the following entries. A process
 198        can use the invisible alias /proc/self if it wishes to open one of its
 199        own /proc files (invisible in the sense that the name ``self'' does not
 200        appear in a directory listing of /proc obtained from ls(1),
 201        getdents(2), or readdir(3C)).
 202 
 203    contracts
 204        A directory containing references to the contracts held by the process.
 205        Each entry is a symlink to the contract's directory under
 206        /system/contract.  See contract(4).
 207 
 208    as
 209        Contains the address-space image of the process; it can be opened for
 210        both reading and writing. lseek(2) is used to position the file at the
 211        virtual address of interest and then the address space can be examined
 212        or changed through read(2) or write(2) (or by using pread(2) or
 213        pwrite(2) for the combined operation).
 214 
 215    ctl
 216        A write-only file to which structured messages are written directing
 217        the system to change some aspect of the process's state or control its
 218        behavior in some way. The seek offset is not relevant when writing to
 219        this file. Individual lwps also have associated lwpctl files in the lwp
 220        subdirectories. A control message may be written either to the
 221        process's ctl file or to a specific lwpctl file with operation-specific
 222        effects. The effect of a control message is immediately reflected in
 223        the state of the process visible through appropriate status and
 224        information files. The types of control messages are described in
 225        detail later. See CONTROL MESSAGES.
 226 
 227    status
 228        Contains state information about the process and the representative
 229        lwp. The file contains a pstatus structure which contains an embedded
 230        lwpstatus structure for the representative lwp, as follows:
 231 
 232          typedef struct pstatus {
 233               int pr_flags;            /* flags (see below) */
 234               int pr_nlwp;             /* number of active lwps in the process */
 235               int pr_nzomb;            /* number of zombie lwps in the process */
 236               pid_tpr_pid;             /* process id */
 237               pid_tpr_ppid;            /* parent process id */
 238               pid_tpr_pgid;            /* process group id */
 239               pid_tpr_sid;             /* session id */
 240               id_t pr_aslwpid;         /* obsolete */
 241               id_t pr_agentid;         /* lwp-id of the agent lwp, if any */
 242               sigset_t pr_sigpend;     /* set of process pending signals */
 243               uintptr_t pr_brkbase;    /* virtual address of the process heap */
 244               size_t pr_brksize;       /* size of the process heap, in bytes */
 245               uintptr_t pr_stkbase;    /* virtual address of the process stack */
 246               size_tpr_stksize;        /* size of the process stack, in bytes */
 247               timestruc_t pr_utime;    /* process user cpu time */
 248               timestruc_t pr_stime;    /* process system cpu time */
 249               timestruc_t pr_cutime;   /* sum of children's user times */
 250               timestruc_t pr_cstime;   /* sum of children's system times */
 251               sigset_t pr_sigtrace;    /* set of traced signals */
 252               fltset_t pr_flttrace;    /* set of traced faults */
 253               sysset_t pr_sysentry;    /* set of system calls traced on entry */
 254               sysset_t pr_sysexit;     /* set of system calls traced on exit */
 255               char pr_dmodel;          /* data model of the process */
 256               taskid_t pr_taskid;      /* task id */
 257               projid_t pr_projid;      /* project id */
 258               zoneid_t pr_zoneid;      /* zone id */
 259               lwpstatus_t pr_lwp;      /* status of the representative lwp */
 260          } pstatus_t;
 261 
 262 
 263 
 264        pr_flags is a bit-mask holding the following process flags. For
 265        convenience, it also contains the lwp flags for the representative lwp,
 266        described later.
 267 
 268        PR_ISSYS
 269                     process is a system process (see PCSTOP).
 270 
 271 
 272        PR_VFORKP
 273                     process is the parent of a vforked child (see PCWATCH).
 274 
 275 
 276        PR_FORK
 277                     process has its inherit-on-fork mode set (see PCSET).
 278 
 279 
 280        PR_RLC
 281                     process has its run-on-last-close mode set (see PCSET).
 282 
 283 
 284        PR_KLC
 285                     process has its kill-on-last-close mode set (see PCSET).
 286 
 287 
 288        PR_ASYNC
 289                     process has its asynchronous-stop mode set (see PCSET).
 290 
 291 
 292        PR_MSACCT
 293                     Set by default in all processes to indicate that
 294                     microstate accounting is enabled. However, this flag has
 295                     been deprecated and no longer has any effect.  Microstate
 296                     accounting may not be disabled; however, it is still
 297                     possible to toggle the flag.
 298 
 299 
 300        PR_MSFORK
 301                     Set by default in all processes to indicate that
 302                     microstate accounting will be enabled for processes that
 303                     this parent forks(). However, this flag has been
 304                     deprecated and no longer has any effect. It is possible to
 305                     toggle this flag; however, it is not possible to disable
 306                     microstate accounting.
 307 
 308 
 309        PR_BPTADJ
 310                     process has its breakpoint adjustment mode set (see
 311                     PCSET).
 312 
 313 
 314        PR_PTRACE
 315                     process has its ptrace-compatibility mode set (see PCSET).
 316 
 317 
 318 
 319        pr_nlwp is the total number of active lwps in the process. pr_nzomb is
 320        the total number of zombie lwps in the process. A zombie lwp is a non-
 321        detached lwp that has terminated but has not been reaped with
 322        thr_join(3C) or pthread_join(3C).
 323 
 324 
 325        pr_pid, pr_ppid, pr_pgid, and pr_sid are, respectively, the process ID,
 326        the ID of the process's parent, the process's process group ID, and the
 327        process's session ID.
 328 
 329 
 330        pr_aslwpid is obsolete and is always zero.
 331 
 332 
 333        pr_agentid is the lwp-ID for the /proc agent lwp (see the PCAGENT
 334        control operation). It is zero if there is no agent lwp in the process.
 335 
 336 
 337        pr_sigpend identifies asynchronous signals pending for the process.
 338 
 339 
 340        pr_brkbase is the virtual address of the process heap and pr_brksize is
 341        its size in bytes. The address formed by the sum of these values is the
 342        process break (see brk(2)). pr_stkbase and pr_stksize are,
 343        respectively, the virtual address of the process stack and its size in
 344        bytes. (Each lwp runs on a separate stack; the distinguishing
 345        characteristic of the process stack is that the operating system will
 346        grow it when necessary.)
 347 
 348 
 349        pr_utime, pr_stime, pr_cutime, and pr_cstime are, respectively, the
 350        user CPU and system CPU time consumed by the process, and the
 351        cumulative user CPU and system CPU time consumed by the process's
 352        children, in seconds and nanoseconds.
 353 
 354 
 355        pr_sigtrace and pr_flttrace contain, respectively, the set of signals
 356        and the set of hardware faults that are being traced (see PCSTRACE and
 357        PCSFAULT).
 358 
 359 
 360        pr_sysentry and pr_sysexit contain, respectively, the sets of system
 361        calls being traced on entry and exit (see PCSENTRY and PCSEXIT).
 362 
 363 
 364        pr_dmodel indicates the data model of the process. Possible values are:
 365 
 366        PR_MODEL_ILP32
 367                           process data model is ILP32.
 368 
 369 
 370        PR_MODEL_LP64
 371                           process data model is LP64.
 372 
 373 
 374        PR_MODEL_NATIVE
 375                           process data model is native.
 376 
 377 
 378 
 379        The pr_taskid, pr_projid, and pr_zoneid fields contain respectively,
 380        the numeric IDs of the task, project, and zone in which the process was
 381        running.
 382 
 383 
 384        The constant PR_MODEL_NATIVE reflects the data model of the controlling
 385        process, that is, its value is PR_MODEL_ILP32 or PR_MODEL_LP64
 386        according to whether the controlling process has been compiled as a
 387        32-bit program or a 64-bit program, respectively.
 388 
 389 
 390        pr_lwp contains the status information for the representative lwp:
 391 
 392          typedef struct lwpstatus {
 393            int pr_flags;              /* flags (see below) */
 394            id_t pr_lwpid;             /* specific lwp identifier */
 395            short pr_why;              /* reason for lwp stop, if stopped */
 396            short pr_what;             /* more detailed reason */
 397            short pr_cursig;           /* current signal, if any */
 398            siginfo_t pr_info;         /* info associated with signal or fault */
 399            sigset_t pr_lwppend;       /* set of signals pending to the lwp */
 400            sigset_t pr_lwphold;       /* set of signals blocked by the lwp */
 401            struct sigaction pr_action;/* signal action for current signal */
 402            stack_t pr_altstack;       /* alternate signal stack info */
 403            uintptr_t pr_oldcontext;   /* address of previous ucontext */
 404            short pr_syscall;          /* system call number (if in syscall) */
 405            short pr_nsysarg;          /* number of arguments to this syscall */
 406            int pr_errno;              /* errno for failed syscall */
 407            long pr_sysarg[PRSYSARGS]; /* arguments to this syscall */
 408            long pr_rval1;             /* primary syscall return value */
 409            long pr_rval2;             /* second syscall return value, if any */
 410            char pr_clname[PRCLSZ];    /* scheduling class name */
 411            timestruc_t pr_tstamp;     /* real-time time stamp of stop */
 412            timestruc_t pr_utime;      /* lwp user cpu time */
 413            timestruc_t pr_stime;      /* lwp system cpu time */
 414            uintptr_t pr_ustack;       /* stack boundary data (stack_t) address */
 415            ulong_t pr_instr;          /* current instruction */
 416            prgregset_t pr_reg;        /* general registers */
 417            prfpregset_t pr_fpreg;     /* floating-point registers */
 418          } lwpstatus_t;
 419 
 420 
 421 
 422        pr_flags is a bit-mask holding the following lwp flags. For
 423        convenience, it also contains the process flags, described previously.
 424 
 425        PR_STOPPED
 426                      The lwp is stopped.
 427 
 428 
 429        PR_ISTOP
 430                      The lwp is stopped on an event of interest (see PCSTOP).
 431 
 432 
 433        PR_DSTOP
 434                      The lwp has a stop directive in effect (see PCSTOP).
 435 
 436 
 437        PR_STEP
 438                      The lwp has a single-step directive in effect (see
 439                      PCRUN).
 440 
 441 
 442        PR_ASLEEP
 443                      The lwp is in an interruptible sleep within a system
 444                      call.
 445 
 446 
 447        PR_PCINVAL
 448                      The lwp's current instruction (pr_instr) is undefined.
 449 
 450 
 451        PR_DETACH
 452                      This is a detached lwp (see pthread_create(3C) and
 453                      pthread_join(3C)).
 454 
 455 
 456        PR_DAEMON
 457                      This is a daemon lwp (see pthread_create(3C)).
 458 
 459 
 460        PR_ASLWP
 461                      This flag is obsolete and is never set.
 462 
 463 
 464        PR_AGENT
 465                      This is the /proc agent lwp for the process.
 466 
 467 
 468 
 469        pr_lwpid names the specific lwp.
 470 
 471 
 472        pr_why and pr_what together describe, for a stopped lwp, the reason for
 473        the stop. Possible values of pr_why and the associated pr_what are:
 474 
 475        PR_REQUESTED
 476                         indicates that the stop occurred in response to a stop
 477                         directive, normally because PCSTOP was applied or
 478                         because another lwp stopped on an event of interest
 479                         and the asynchronous-stop flag (see PCSET) was not set
 480                         for the process. pr_what is unused in this case.
 481 
 482 
 483        PR_SIGNALLED
 484                         indicates that the lwp stopped on receipt of a signal
 485                         (see PCSTRACE); pr_what holds the signal number that
 486                         caused the stop (for a newly-stopped lwp, the same
 487                         value is in pr_cursig).
 488 
 489 
 490        PR_FAULTED
 491                         indicates that the lwp stopped on incurring a hardware
 492                         fault (see PCSFAULT); pr_what holds the fault number
 493                         that caused the stop.
 494 
 495 
 496        PR_SYSENTRY
 497        PR_SYSEXIT
 498                         indicate a stop on entry to or exit from a system call
 499                         (see PCSENTRY and PCSEXIT); pr_what holds the system
 500                         call number.
 501 
 502 
 503        PR_JOBCONTROL
 504                         indicates that the lwp stopped due to the default
 505                         action of a job control stop signal (see
 506                         sigaction(2)); pr_what holds the stopping signal
 507                         number.
 508 
 509 
 510        PR_SUSPENDED
 511                         indicates that the lwp stopped due to internal
 512                         synchronization of lwps within the process. pr_what is
 513                         unused in this case.
 514 
 515 
 516 
 517        pr_cursig names the current signal, that is, the next signal to be
 518        delivered to the lwp, if any. pr_info, when the lwp is in a
 519        PR_SIGNALLED or PR_FAULTED stop, contains additional information
 520        pertinent to the particular signal or fault (see <sys/siginfo.h>).
 521 
 522 
 523        pr_lwppend identifies any synchronous or directed signals pending for
 524        the lwp. pr_lwphold identifies those signals whose delivery is being
 525        blocked by the lwp (the signal mask).
 526 
 527 
 528        pr_action contains the signal action information pertaining to the
 529        current signal (see sigaction(2)); it is undefined if pr_cursig is
 530        zero. pr_altstack contains the alternate signal stack information for
 531        the lwp (see sigaltstack(2)).
 532 
 533 
 534        pr_oldcontext, if not zero, contains the address on the lwp stack of a
 535        ucontext structure describing the previous user-level context (see
 536        ucontext.h(3HEAD)). It is non-zero only if the lwp is executing in the
 537        context of a signal handler.
 538 
 539 
 540        pr_syscall is the number of the system call, if any, being executed by
 541        the lwp; it is non-zero if and only if the lwp is stopped on
 542        PR_SYSENTRY or PR_SYSEXIT, or is asleep within a system call (
 543        PR_ASLEEP is set). If pr_syscall is non-zero, pr_nsysarg is the number
 544        of arguments to the system call and pr_sysarg contains the actual
 545        arguments.
 546 
 547 
 548        pr_rval1, pr_rval2, and pr_errno are defined only if the lwp is stopped
 549        on PR_SYSEXIT or if the PR_VFORKP flag is set. If pr_errno is zero,
 550        pr_rval1 and pr_rval2 contain the return values from the system call.
 551        Otherwise, pr_errno contains the error number for the failing system
 552        call (see <sys/errno.h>).
 553 
 554 
 555        pr_clname contains the name of the lwp's scheduling class.
 556 
 557 
 558        pr_tstamp, if the lwp is stopped, contains a time stamp marking when
 559        the lwp stopped, in real time seconds and nanoseconds since an
 560        arbitrary time in the past.
 561 
 562 
 563        pr_utime is the amount of user level CPU time used by this LWP.
 564 
 565 
 566        pr_stime is the amount of system level CPU time used by this LWP.
 567 
 568 
 569        pr_ustack is the virtual address of the stack_t that contains the stack
 570        boundaries for this LWP. See getustack(2) and _stack_grow(3C).
 571 
 572 
 573        pr_instr contains the machine instruction to which the lwp's program
 574        counter refers. The amount of data retrieved from the process is
 575        machine-dependent. On SPARC based machines, it is a 32-bit word. On
 576        x86-based machines, it is a single byte. In general, the size is that
 577        of the machine's smallest instruction. If PR_PCINVAL is set, pr_instr
 578        is undefined; this occurs whenever the lwp is not stopped or when the
 579        program counter refers to an invalid virtual address.
 580 
 581 
 582        pr_reg is an array holding the contents of a stopped lwp's general
 583        registers.
 584 
 585        SPARC
 586                             On SPARC-based machines, the predefined constants
 587                             R_G0 ... R_G7, R_O0 ... R_O7, R_L0 ... R_L7, R_I0
 588                             ...  R_I7, R_PC, R_nPC, and R_Y can be used as
 589                             indices to refer to the corresponding registers;
 590                             previous register windows can be read from their
 591                             overflow locations on the stack (however, see the
 592                             gwindows file in the /proc/pid/lwp/lwpid
 593                             subdirectory).
 594 
 595 
 596        SPARC V8 (32-bit)
 597                             For SPARC V8 (32-bit) controlling processes, the
 598                             predefined constants R_PSR, R_WIM, and R_TBR can
 599                             be used as indices to refer to the corresponding
 600                             special registers. For SPARC V9 (64-bit)
 601                             controlling processes, the predefined constants
 602                             R_CCR, R_ASI, and R_FPRS can be used as indices to
 603                             refer to the corresponding special registers.
 604 
 605 
 606        x86 (32-bit)
 607                             For 32-bit x86 processes, the predefined constants
 608                             listed belowcan be used as indices to refer to the
 609                             corresponding registers.
 610 
 611                               SS
 612                               UESP
 613                               EFL
 614                               CS
 615                               EIP
 616                               ERR
 617                               TRAPNO
 618                               EAX
 619                               ECX
 620                               EDX
 621                               EBX
 622                               ESP
 623                               EBP
 624                               ESI
 625                               EDI
 626                               DS
 627                               ES
 628                               GS
 629 
 630                             The preceding constants are listed in
 631                             <sys/regset.h>.
 632 
 633                             Note that a 32-bit process can run on an x86
 634                             64-bit system, using the constants listed above.
 635 
 636 
 637        x86 (64-bit)
 638                             To read the registers of a 32- or a 64-bit
 639                             process, a 64-bit x86 process should use the
 640                             predefined constants listed below.
 641 
 642                               REG_GSBASE
 643                               REG_FSBASE
 644                               REG_DS
 645                               REG_ES
 646                               REG_GS
 647                               REG_FS
 648                               REG_SS
 649                               REG_RSP
 650                               REG_RFL
 651                               REG_CS
 652                               REG_RIP
 653                               REG_ERR
 654                               REG_TRAPNO
 655                               REG_RAX
 656                               REG_RCX
 657                               REG_RDX
 658                               REG_RBX
 659                               REG_RBP
 660                               REG_RSI
 661                               REG_RDI
 662                               REG_R8
 663                               REG_R9
 664                               REG_R10
 665                               REG_R11
 666                               REG_R12
 667                               REG_R13
 668                               REG_R14
 669                               REG_R15
 670 
 671                             The preceding constants are listed in
 672                             <sys/regset.h>.
 673 
 674 
 675 
 676        pr_fpreg is a structure holding the contents of the floating-point
 677        registers.
 678 
 679 
 680        SPARC registers, both general and floating-point, as seen by a 64-bit
 681        controlling process are the V9 versions of the registers, even if the
 682        target process is a 32-bit (V8) process. V8 registers are a subset of
 683        the V9 registers.
 684 
 685 
 686        If the lwp is not stopped, all register values are undefined.
 687 
 688    psinfo
 689        Contains miscellaneous information about the process and the
 690        representative lwp needed by the ps(1) command. psinfo remains
 691        accessible after a process becomes a zombie. The file contains a psinfo
 692        structure which contains an embedded lwpsinfo structure for the
 693        representative lwp, as follows:
 694 
 695          typedef struct psinfo {
 696              int pr_flag;             /* process flags (DEPRECATED: see below) */
 697              int pr_nlwp;             /* number of active lwps in the process */
 698              int pr_nzomb;            /* number of zombie lwps in the process */
 699              pid_t pr_pid;            /* process id */
 700              pid_t pr_ppid;           /* process id of parent */
 701              pid_t pr_pgid;           /* process id of process group leader */
 702              pid_t pr_sid;            /* session id */
 703              uid_t pr_uid;            /* real user id */
 704              uid_t pr_euid;           /* effective user id */
 705              gid_t pr_gid;            /* real group id */
 706              gid_t pr_egid;           /* effective group id */
 707              uintptr_t pr_addr;       /* address of process */
 708              size_t pr_size;          /* size of process image in Kbytes */
 709              size_t pr_rssize;        /* resident set size in Kbytes */
 710              dev_t pr_ttydev;         /* controlling tty device (or PRNODEV) */
 711              ushort_t pr_pctcpu;      /* % of recent cpu time used by all lwps */
 712              ushort_t pr_pctmem;      /* % of system memory used by process */
 713              timestruc_t pr_start;    /* process start time, from the epoch */
 714              timestruc_t pr_time;     /* cpu time for this process */
 715              timestruc_t pr_ctime;    /* cpu time for reaped children */
 716              char pr_fname[PRFNSZ];   /* name of exec'ed file */
 717              char pr_psargs[PRARGSZ]; /* initial characters of arg list */
 718              int pr_wstat;            /* if zombie, the wait() status */
 719              int pr_argc;             /* initial argument count */
 720              uintptr_t pr_argv;       /* address of initial argument vector */
 721              uintptr_t pr_envp;       /* address of initial environment vector */
 722              char pr_dmodel;          /* data model of the process */
 723              taskid_t pr_taskid;      /* task id */
 724              projid_t pr_projid;      /* project id */
 725              poolid_t pr_poolid;      /* pool id */
 726              zoneid_t pr_zoneid;      /* zone id */
 727              ctid_t pr_contract;      /* process contract id */
 728              lwpsinfo_t pr_lwp;       /* information for representative lwp */
 729          } psinfo_t;
 730 
 731 
 732 
 733        Some of the entries in psinfo, such as pr_addr, refer to internal
 734        kernel data structures and should not be expected to retain their
 735        meanings across different versions of the operating system.
 736 
 737 
 738        psinfo_t.pr_flag is a deprecated interface that should no longer be
 739        used.  Applications currently relying on the SSYS bit in pr_flag should
 740        migrate to checking PR_ISSYS in the pstatus structure's pr_flags field.
 741 
 742 
 743        pr_pctcpu and pr_pctmem are 16-bit binary fractions in the range 0.0 to
 744        1.0 with the binary point to the right of the high-order bit (1.0 ==
 745        0x8000). pr_pctcpu is the summation over all lwps in the process.
 746 
 747 
 748        pr_lwp contains the ps(1) information for the representative lwp.  If
 749        the process is a zombie, pr_nlwp, pr_nzomb, and pr_lwp.pr_lwpid are
 750        zero and the other fields of pr_lwp are undefined:
 751 
 752          typedef struct lwpsinfo {
 753              int pr_flag;             /* lwp flags (DEPRECATED: see below) */
 754              id_t pr_lwpid;           /* lwp id */
 755              uintptr_t pr_addr;       /* internal address of lwp */
 756              uintptr_t pr_wchan;      /* wait addr for sleeping lwp */
 757              char pr_stype;           /* synchronization event type */
 758              char pr_state;           /* numeric lwp state */
 759              char pr_sname;           /* printable character for pr_state */
 760              char pr_nice;            /* nice for cpu usage */
 761              short pr_syscall;        /* system call number (if in syscall) */
 762              char pr_oldpri;          /* pre-SVR4, low value is high priority */
 763              char pr_cpu;             /* pre-SVR4, cpu usage for scheduling */
 764              int pr_pri;              /* priority, high value = high priority */
 765              ushort_t pr_pctcpu;      /* % of recent cpu time used by this lwp */
 766              timestruc_t pr_start;    /* lwp start time, from the epoch */
 767              timestruc_t pr_time;     /* cpu time for this lwp */
 768              char pr_clname[PRCLSZ];  /* scheduling class name */
 769              char pr_name[PRFNSZ];    /* name of system lwp */
 770              processorid_t pr_onpro;  /* processor which last ran this lwp */
 771              processorid_t pr_bindpro;/* processor to which lwp is bound */
 772              psetid_t pr_bindpset;    /* processor set to which lwp is bound */
 773              lgrp_id_t pr_lgrp          /* home lgroup */
 774          } lwpsinfo_t;
 775 
 776 
 777 
 778        Some of the entries in lwpsinfo, such as pr_addr, pr_wchan, pr_stype,
 779        pr_state, and pr_name, refer to internal kernel data structures and
 780        should not be expected to retain their meanings across different
 781        versions of the operating system.
 782 
 783 
 784        lwpsinfo_t.pr_flag is a deprecated interface that should no longer be
 785        used.
 786 
 787 
 788        pr_pctcpu is a 16-bit binary fraction, as described above. It
 789        represents the CPU time used by the specific lwp. On a multi-processor
 790        machine, the maximum value is 1/N, where N is the number of CPUs.
 791 
 792 
 793        pr_contract is the id of the process contract of which the process is a
 794        member. See contract(4) and process(4).
 795 
 796    cred
 797        Contains a description of the credentials associated with the process:
 798 
 799          typedef struct prcred {
 800               uid_t pr_euid;      /* effective user id */
 801               uid_t pr_ruid;      /* real user id */
 802               uid_t pr_suid;      /* saved user id (from exec) */
 803               gid_t pr_egid;      /* effective group id */
 804               gid_t pr_rgid;      /* real group id */
 805               gid_t pr_sgid;      /* saved group id (from exec) */
 806               int pr_ngroups;     /* number of supplementary groups */
 807               gid_t pr_groups[1]; /* array of supplementary groups */
 808          } prcred_t;
 809 
 810 
 811 
 812 
 813        The array of associated supplementary groups in pr_groups is of
 814        variable length; the cred file contains all of the supplementary
 815        groups.  pr_ngroups indicates the number of supplementary groups. (See
 816        also the PCSCRED and PCSCREDX control operations.)
 817 
 818    priv
 819        Contains a description of the privileges associated with the process:
 820 
 821          typedef struct prpriv {
 822               uint32_t        pr_nsets;      /* number of privilege set */
 823               uint32_t        pr_setsize;    /* size of privilege set */
 824               uint32_t        pr_infosize;   /* size of supplementary data */
 825               priv_chunk_t    pr_sets[1];    /* array of sets */
 826          } prpriv_t;
 827 
 828 
 829 
 830        The actual dimension of the pr_sets[] field is
 831 
 832          pr_sets[pr_nsets][pr_setsize]
 833 
 834 
 835 
 836        which is followed by additional information about the process state
 837        pr_infosize bytes in size.
 838 
 839 
 840        The full size of the structure can be computed using
 841        PRIV_PRPRIV_SIZE(prpriv_t *).
 842 
 843    secflags
 844        This file contains the security-flags of the process.  It contains a
 845        description of the security flags associated with the process.
 846 
 847          typedef struct prsecflags {
 848               uint32_t pr_version;          /* ABI Versioning of this structure */
 849               secflagset_t pr_effective;    /* Effective flags */
 850               secflagset_t pr_inherit; /* Inheritable flags */
 851               secflagset_t pr_lower;        /* Lower flags */
 852               secflagset_t pr_upper;        /* Upper flags */
 853          } prsecflags_t;
 854 
 855 
 856 
 857        The pr_version field is a version number for the structure, currently
 858        PRSECFLAGS_VERSION_1.
 859 
 860    sigact
 861        Contains an array of sigaction structures describing the current
 862        dispositions of all signals associated with the traced process (see
 863        sigaction(2)). Signal numbers are displaced by 1 from array indices, so
 864        that the action for signal number n appears in position n-1 of the
 865        array.
 866 
 867    auxv
 868        Contains the initial values of the process's aux vector in an array of
 869        auxv_t structures (see <sys/auxv.h>). The values   are those that were
 870        passed by the operating system as startup information to the dynamic
 871        linker.
 872 
 873    ldt
 874        This file exists only on x86-based machines. It is non-empty only if
 875        the process has established a local descriptor table (LDT). If non-
 876        empty, the file contains the array of currently active LDT entries in
 877        an array of elements of type struct ssd, defined in <sys/sysi86.h>, one
 878        element for each active LDT entry.
 879 
 880    map, xmap
 881        Contain information about the virtual address map of the process. The
 882        map file contains an array of prmap structures while the xmap file
 883        contains an array of prxmap structures. Each structure describes a
 884        contiguous virtual address region in the address space of the traced
 885        process:
 886 
 887          typedef struct prmap {
 888               uintptr_tpr_vaddr;         /* virtual address of mapping */
 889               size_t pr_size;            /* size of mapping in bytes */
 890               char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
 891               offset_t pr_offset;        /* offset into mapped object, if any */
 892               int pr_mflags;             /* protection and attribute flags */
 893               int pr_pagesize;           /* pagesize for this mapping in bytes */
 894               int pr_shmid;              /* SysV shared memory identifier */
 895          } prmap_t;
 896 
 897 
 898 
 899          typedef struct prxmap {
 900               uintptr_t pr_vaddr;        /* virtual address of mapping */
 901               size_t pr_size;            /* size of mapping in bytes */
 902               char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
 903               offset_t pr_offset;        /* offset into mapped object, if any */
 904               int pr_mflags;             /* protection and attribute flags */
 905               int pr_pagesize;           /* pagesize for this mapping in bytes */
 906               int pr_shmid;              /* SysV shared memory identifier */
 907               dev_t pr_dev;              /* device of mapped object, if any */
 908               uint64_t pr_ino;           /* inode of mapped object, if any */
 909               size_t pr_rss;             /* pages of resident memory */
 910               size_t pr_anon;            /* pages of resident anonymous memory */
 911               size_t pr_locked;          /* pages of locked memory */
 912               uint64_t pr_hatpagesize;   /* pagesize of mapping */
 913          } prxmap_t;
 914 
 915 
 916 
 917 
 918        pr_vaddr is the virtual address of the mapping within the traced
 919        process and pr_size is its size in bytes. pr_mapname, if it does not
 920        contain a null string, contains the name of a file in the object
 921        directory (see below) that can be opened read-only to obtain a file
 922        descriptor for the mapped file associated with the mapping. This
 923        enables a debugger to find object file symbol tables without having to
 924        know the real path names of the executable file and shared libraries of
 925        the process. pr_offset is the 64-bit offset within the mapped file (if
 926        any) to which the virtual address is mapped.
 927 
 928 
 929        pr_mflags is a bit-mask of protection and attribute flags:
 930 
 931        MA_READ
 932                         mapping is readable by the traced process.
 933 
 934 
 935        MA_WRITE
 936                         mapping is writable by the traced process.
 937 
 938 
 939        MA_EXEC
 940                         mapping is executable by the traced process.
 941 
 942 
 943        MA_SHARED
 944                         mapping changes are shared by the mapped object.
 945 
 946 
 947        MA_ISM
 948                         mapping is intimate shared memory (shared MMU
 949                         resources)
 950 
 951 
 952        MAP_NORESERVE
 953                         mapping does not have swap space reserved (mapped with
 954                         MAP_NORESERVE)
 955 
 956 
 957        MA_SHM
 958                         mapping System V shared memory
 959 
 960 
 961 
 962        A contiguous area of the address space having the same underlying
 963        mapped object may appear as multiple mappings due to varying read,
 964        write, and execute attributes. The underlying mapped object does not
 965        change over the range of a single mapping. An I/O operation to a
 966        mapping marked MA_SHARED fails if applied at a virtual address not
 967        corresponding to a valid page in the underlying mapped object. A write
 968        to a MA_SHARED mapping that is not marked MA_WRITE fails. Reads and
 969        writes to private mappings always succeed. Reads and writes to unmapped
 970        addresses fail.
 971 
 972 
 973        pr_pagesize is the page size for the mapping, currently always the
 974        system pagesize.
 975 
 976 
 977        pr_shmid is the shared memory identifier, if any, for the mapping. Its
 978        value is -1 if the mapping is not System V shared memory. See
 979        shmget(2).
 980 
 981 
 982        pr_dev is the device of the mapped object, if any, for the mapping. Its
 983        value is PRNODEV (-1) if the mapping does not have a device.
 984 
 985 
 986        pr_ino is the inode of the mapped object, if any, for the mapping. Its
 987        contents are only valid if pr_dev is not PRNODEV.
 988 
 989 
 990        pr_rss is the number of resident pages of memory for the mapping. The
 991        number of resident bytes for the mapping may be determined by
 992        multiplying pr_rss by the page size given by pr_pagesize.
 993 
 994 
 995        pr_anon is the number of resident anonymous memory pages (pages which
 996        are private to this process) for the mapping.
 997 
 998 
 999        pr_locked is the number of locked pages for the mapping. Pages which
1000        are locked are always resident in memory.
1001 
1002 
1003        pr_hatpagesize is the size, in bytes, of the HAT (MMU) translation for
1004        the mapping. pr_hatpagesize may be different than pr_pagesize. The
1005        possible values are hardware architecture specific, and may change over
1006        a mapping's lifetime.
1007 
1008    rmap
1009        Contains information about the reserved address ranges of the process.
1010        The file contains an array of prmap structures, as defined above for
1011        the map file. Each structure describes a contiguous virtual address
1012        region in the address space of the traced process that is reserved by
1013        the system in the sense that an mmap(2) system call that does not
1014        specify MAP_FIXED will not use any part of it for the new mapping.
1015        Examples of such reservations include the address ranges reserved for
1016        the process stack and the individual thread stacks of a multi-threaded
1017        process.
1018 
1019    cwd
1020        A symbolic link to the process's current working directory. See
1021        chdir(2).  A readlink(2) of /proc/pid/cwd yields a null string.
1022        However, it can be opened, listed, and searched as a directory, and can
1023        be the target of chdir(2).
1024 
1025    root
1026        A symbolic link to the process's root directory.  /proc/pid/root can
1027        differ from the system root directory if the process or one of its
1028        ancestors executed chroot(2) as super user. It has the same semantics
1029        as /proc/pid/cwd.
1030 
1031    fd
1032        A directory containing references to the open files of the process.
1033        Each entry is a decimal number corresponding to an open file descriptor
1034        in the process.
1035 
1036 
1037        If an entry refers to a regular file, it can be opened with normal file
1038        system semantics but, to ensure that the controlling process cannot
1039        gain greater access than the controlled process, with no file access
1040        modes other than its read/write open modes in the controlled process.
1041        If an entry refers to a directory, it can be accessed with the same
1042        semantics as /proc/pid/cwd. An attempt to open any other type of entry
1043        fails with EACCES.
1044 
1045    object
1046        A directory containing read-only files with names corresponding to the
1047        pr_mapname entries in the map and pagedata files. Opening such a file
1048        yields a file descriptor for the underlying mapped file associated with
1049        an address-space mapping in the process. The file name a.out appears in
1050        the directory as an alias for the process's executable file.
1051 
1052 
1053        The object directory makes it possible for a controlling process to
1054        gain access to the object file and any shared libraries (and
1055        consequently the symbol tables) without having to know the actual path
1056        names of the executable files.
1057 
1058    path
1059        A directory containing symbolic links to files opened by the process.
1060        The directory includes one entry for cwd and root. The directory also
1061        contains a numerical entry for each file descriptor in the fd
1062        directory, and entries matching those in the object directory. If this
1063        information is not available, any attempt to read the contents of the
1064        symbolic link will fail. This is most common for files that do not
1065        exist in the filesystem namespace (such as FIFOs and sockets), but can
1066        also happen for regular files. For the file descriptor entries, the
1067        path may be different from the one used by the process to open the
1068        file.
1069 
1070    pagedata
1071        Opening the page data file enables tracking of address space references
1072        and modifications on a per-page basis.
1073 
1074 
1075        A read(2) of the page data file descriptor returns structured page data
1076        and atomically clears the page data maintained for the file by the
1077        system. That is to say, each read returns data collected since the last
1078        read; the first read returns data collected since the file was opened.
1079        When the call completes, the read buffer contains the following
1080        structure as its header and thereafter contains a number of section
1081        header structures and associated byte arrays that must be accessed by
1082        walking linearly through the buffer.
1083 
1084          typedef struct prpageheader {
1085              timestruc_t pr_tstamp; /* real time stamp, time of read() */
1086              ulong_t pr_nmap;       /* number of address space mappings */
1087              ulong_t pr_npage;      /* total number of pages */
1088          } prpageheader_t;
1089 
1090 
1091 
1092        The header is followed by pr_nmap prasmap structures and associated
1093        data arrays. The prasmap structure contains the following elements:
1094 
1095          typedef struct prasmap {
1096              uintptr_t pr_vaddr;        /* virtual address of mapping */
1097              ulong_t pr_npage;          /* number of pages in mapping */
1098              char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
1099              offset_t pr_offset;        /* offset into mapped object, if any */
1100              int pr_mflags;             /* protection and attribute flags */
1101              int pr_pagesize;           /* pagesize for this mapping in bytes */
1102              int pr_shmid;              /* SysV shared memory identifier */
1103          } prasmap_t;
1104 
1105 
1106 
1107        Each section header is followed by pr_npage bytes, one byte for each
1108        page in the mapping, plus 0-7 null bytes at the end so that the next
1109        prasmap structure begins on an eight-byte aligned boundary. Each data
1110        byte may contain these flags:
1111 
1112        PG_REFERENCED
1113                         page has been referenced.
1114 
1115 
1116        PG_MODIFIED
1117                         page has been modified.
1118 
1119 
1120 
1121        If the read buffer is not large enough to contain all of the page data,
1122        the read fails with E2BIG and the page data is not cleared. The
1123        required size of the read buffer can be determined through fstat(2).
1124        Application of lseek(2) to the page data file descriptor is
1125        ineffective; every read starts from the beginning of the file. Closing
1126        the page data file descriptor terminates the system overhead associated
1127        with collecting the data.
1128 
1129 
1130        More than one page data file descriptor for the same process can be
1131        opened, up to a system-imposed limit per traced process. A read of one
1132        does not affect the data being collected by the system for the others.
1133        An open of the page data file will fail with ENOMEM if the system-
1134        imposed limit would be exceeded.
1135 
1136    watch
1137        Contains an array of prwatch structures, one for each watched area
1138        established by the PCWATCH control operation. See PCWATCH for details.
1139 
1140    usage
1141        Contains process usage information described by a prusage structure
1142        which contains at least the following fields:
1143 
1144          typedef struct prusage {
1145              id_t pr_lwpid;           /* lwp id.  0: process or defunct */
1146              int pr_count;            /* number of contributing lwps */
1147              timestruc_t pr_tstamp;   /* real time stamp, time of read() */
1148              timestruc_t pr_create;   /* process/lwp creation time stamp */
1149              timestruc_t pr_term;     /* process/lwp termination time stamp */
1150              timestruc_t pr_rtime;    /* total lwp real (elapsed) time */
1151              timestruc_t pr_utime;    /* user level CPU time */
1152              timestruc_t pr_stime;    /* system call CPU time */
1153              timestruc_t pr_ttime;    /* other system trap CPU time */
1154              timestruc_t pr_tftime;   /* text page fault sleep time */
1155              timestruc_t pr_dftime;   /* data page fault sleep time */
1156              timestruc_t pr_kftime;   /* kernel page fault sleep time */
1157              timestruc_t pr_ltime;    /* user lock wait sleep time */
1158              timestruc_t pr_slptime;  /* all other sleep time */
1159              timestruc_t pr_wtime;    /* wait-cpu (latency) time */
1160              timestruc_t pr_stoptime; /* stopped time */
1161              ulong_t pr_minf;         /* minor page faults */
1162              ulong_t pr_majf;         /* major page faults */
1163              ulong_t pr_nswap;        /* swaps */
1164              ulong_t pr_inblk;        /* input blocks */
1165              ulong_t pr_oublk;        /* output blocks */
1166              ulong_t pr_msnd;         /* messages sent */
1167              ulong_t pr_mrcv;         /* messages received */
1168              ulong_t pr_sigs;         /* signals received */
1169              ulong_t pr_vctx;         /* voluntary context switches */
1170              ulong_t pr_ictx;         /* involuntary context switches */
1171              ulong_t pr_sysc;         /* system calls */
1172              ulong_t pr_ioch;         /* chars read and written */
1173          } prusage_t;
1174 
1175 
1176 
1177        Microstate accounting is now continuously enabled. While this
1178        information was previously an estimate, if microstate accounting were
1179        not enabled, the current information is now never an estimate
1180        represents time the process has spent in various states.
1181 
1182    lstatus
1183        Contains a prheader structure followed by an array of lwpstatus
1184        structures, one for each active lwp in the process (see also
1185        /proc/pid/lwp/lwpid/lwpstatus, below). The prheader structure describes
1186        the number and size of the array entries that follow.
1187 
1188          typedef struct prheader {
1189              long pr_nent;        /* number of entries */
1190              size_t pr_entsize;   /* size of each entry, in bytes */
1191          } prheader_t;
1192 
1193 
1194 
1195        The lwpstatus structure may grow by the addition of elements at the end
1196        in future releases of the system. Programs must use pr_entsize in the
1197        file header to index through the array. These comments apply to all
1198        /proc files that include a prheader structure (lpsinfo and lusage,
1199        below).
1200 
1201    lpsinfo
1202        Contains a prheader structure followed by an array of lwpsinfo
1203        structures, one for eachactive and zombie lwp in the process. See also
1204        /proc/pid/lwp/lwpid/lwpsinfo, below.
1205 
1206    lusage
1207        Contains a prheader structure followed by an array of prusage
1208        structures, one for each active lwp in the process, plus an additional
1209        element at the beginning that contains the summation over all defunct
1210        lwps (lwps that once existed but no longer exist in the process).
1211        Excluding the pr_lwpid, pr_tstamp, pr_create, and pr_term entries, the
1212        entry-by-entry summation over all these structures is the definition of
1213        the process usage information obtained from the usage file. (See also
1214        /proc/pid/lwp/lwpid/lwpusage, below.)
1215 
1216    lwp
1217        A directory containing entries each of which names an active or zombie
1218        lwp within the process. These entries are themselves directories
1219        containing additional files as described below. Only the lwpsinfo file
1220        exists in the directory of a zombie lwp.
1221 
1222 STRUCTURE OF /proc/pid/lwp/lwpid
1223        A given directory /proc/pid/lwp/lwpid contains the following entries:
1224 
1225    lwpctl
1226        Write-only control file. The messages written to this file affect the
1227        specific lwp rather than the representative lwp, as is the case for the
1228        process's ctl file.
1229 
1230    lwpname
1231        A buffer of THREAD_NAME_MAX bytes representing the LWP name; the buffer
1232        is zero-filled if the thread name is shorter than the buffer. If no
1233        thread name is set, the buffer contains the empty string. A read with a
1234        buffer shorter than THREAD_NAME_MAX bytes is not guaranteed to be NUL-
1235        terminated.  Writing to this file will set the LWP name for the
1236        specific lwp.  This file may not be present in older operating system
1237        versions. THREAD_NAME_MAX may increase in the future; clients should be
1238        prepared for this.
1239 
1240    lwpstatus
1241        lwp-specific state information. This file contains the lwpstatus
1242        structure for the specific lwp as described above for the
1243        representative lwp in the process's status file.
1244 
1245    lwpsinfo
1246        lwp-specific ps(1) information. This file contains the lwpsinfo
1247        structure for the specific lwp as described above for the
1248        representative lwp in the process's psinfo file. The lwpsinfo file
1249        remains accessible after an lwp becomes a zombie.
1250 
1251    lwpusage
1252        This file contains the prusage structure for the specific lwp as
1253        described above for the process's usage file.
1254 
1255    gwindows
1256        This file exists only on SPARC based machines. If it is non-empty, it
1257        contains a gwindows_t structure, defined in <sys/regset.h>, with   the
1258        values of those SPARC register windows that could not be stored on the
1259        stack when the lwp stopped. Conditions under which register windows are
1260        not stored on the stack are: the stack pointer refers to nonexistent
1261        process memory or the stack pointer is improperly aligned. If the lwp
1262        is not stopped or if there are no register windows that could not be
1263        stored on the stack, the file is empty (the usual case).
1264 
1265    xregs
1266        Extra state registers. The extra state register set is architecture
1267        dependent; this file is empty if the system does not support extra
1268        state registers. If the file is non-empty, it contains an architecture
1269        dependent structure of type prxregset_t, defined in <procfs.h>, with
1270        the values of the lwp's extra state registers. If the lwp is not
1271        stopped, all register values are undefined. See also the PCSXREG
1272        control operation, below.
1273 
1274    asrs
1275        This file exists only for 64-bit SPARC V9 processes. It contains an
1276        asrset_t structure, defined in <sys/regset.h>, containing the values of
1277        the lwp's platform-dependent ancillary state registers. If the lwp is
1278        not stopped, all register values are undefined. See also the PCSASRS
1279        control operation, below.
1280 
1281    spymaster
1282        For an agent lwp (see PCAGENT), this file contains a psinfo_t structure
1283        that corresponds to the process that created the agent lwp at the time
1284        the agent was created. This structure is identical to that retrieved
1285        via the psinfo file, with one modification: the pr_time field does not
1286        correspond to the CPU time for the process, but rather to the creation
1287        time of the agent lwp.
1288 
1289    templates
1290        A directory which contains references to the active templates for the
1291        lwp, named by the contract type. Changes made to an active template
1292        descriptor do not affect the original template which was activated,
1293        though they do affect the active template. It is not possible to
1294        activate an active template descriptor.  See contract(4).
1295 
1296 CONTROL MESSAGES
1297        Process state changes are effected through messages written to a
1298        process's ctl file or to an individual lwp's lwpctl file. All control
1299        messages consist of a long that names the specific operation followed
1300        by additional data containing the operand, if any.
1301 
1302 
1303        Multiple control messages may be combined in a single write(2) (or
1304        writev(2)) to a control file, but no partial writes are permitted. That
1305        is, each control message, operation code plus operand, if any, must be
1306        presented in its entirety to the write(2) and not in pieces over
1307        several system calls. If a control operation fails, no subsequent
1308        operations contained in the same write(2) are attempted.
1309 
1310 
1311        Descriptions of the allowable control messages follow. In all cases,
1312        writing a message to a control file for a process or lwp that has
1313        terminated elicits the error ENOENT.
1314 
1315    PCSTOP PCDSTOP PCWSTOP PCTWSTOP
1316        When applied to the process control file, PCSTOP directs all lwps to
1317        stop and waits for them to stop, PCDSTOP directs all lwps to stop
1318        without waiting for them to stop, and PCWSTOP simply waits for all lwps
1319        to stop.  When applied to an lwp control file, PCSTOP directs the
1320        specific lwp to stop and waits until it has stopped, PCDSTOP directs
1321        the specific lwp to stop without waiting for it to stop, and PCWSTOP
1322        simply waits for the specific lwp to stop. When applied to an lwp
1323        control file, PCSTOP and PCWSTOP complete when the lwp stops on an
1324        event of interest, immediately if already so stopped; when applied to
1325        the process control file, they complete when every lwp has stopped
1326        either on an event of interest or on a PR_SUSPENDED stop.
1327 
1328 
1329        PCTWSTOP is identical to PCWSTOP except that it enables the operation
1330        to time out, to avoid waiting forever for a process or lwp that may
1331        never stop on an event of interest. PCTWSTOP takes a long operand
1332        specifying a number of milliseconds; the wait will terminate
1333        successfully after the specified number of milliseconds even if the
1334        process or lwp has not stopped; a timeout value of zero makes the
1335        operation identical to PCWSTOP.
1336 
1337 
1338        An ``event of interest'' is either a PR_REQUESTED stop or a stop that
1339        has been specified in the process's tracing flags (set by PCSTRACE,
1340        PCSFAULT, PCSENTRY, and PCSEXIT). PR_JOBCONTROL and PR_SUSPENDED stops
1341        are specifically not events of interest. (An lwp may stop twice due to
1342        a stop signal, first showing PR_SIGNALLED if the signal is traced and
1343        again showing PR_JOBCONTROL if the lwp is set running without clearing
1344        the signal.) If PCSTOP or PCDSTOP is applied to an lwp that is stopped,
1345        but not on an event of interest, the stop directive takes effect when
1346        the lwp is restarted by the competing mechanism. At that time, the lwp
1347        enters a PR_REQUESTED stop before executing any user-level code.
1348 
1349 
1350        A write of a control message that blocks is interruptible by a signal
1351        so that, for example, an alarm(2) can be set to avoid waiting forever
1352        for a process or lwp that may never stop on an event of interest. If
1353        PCSTOP is interrupted, the lwp stop directives remain in effect even
1354        though the write(2) returns an error. (Use of PCTWSTOP with a non-zero
1355        timeout is recommended over PCWSTOP with an alarm(2).)
1356 
1357 
1358        A system process (indicated by the PR_ISSYS flag) never executes at
1359        user level, has no user-level address space visible through /proc, and
1360        cannot be stopped. Applying one of these operations to a system process
1361        or any of its lwps elicits the error EBUSY.
1362 
1363    PCRUN
1364        Make an lwp runnable again after a stop. This operation takes a long
1365        operand containing zero or more of the following flags:
1366 
1367        PRCSIG
1368                    clears the current signal, if any (see PCCSIG).
1369 
1370 
1371        PRCFAULT
1372                    clears the current fault, if any (see PCCFAULT).
1373 
1374 
1375        PRSTEP
1376                    directs the lwp to execute a single machine instruction. On
1377                    completion of the instruction, a trace trap occurs. If
1378                    FLTTRACE is being traced, the lwp stops; otherwise, it is
1379                    sent SIGTRAP. If SIGTRAP is being traced and is not
1380                    blocked, the lwp stops. When the lwp stops on an event of
1381                    interest, the single-step directive is cancelled, even if
1382                    the stop occurs before the instruction is executed. This
1383                    operation requires hardware and operating system support
1384                    and may not be implemented on all processors. It is
1385                    implemented on SPARC and x86-based machines.
1386 
1387 
1388        PRSABORT
1389                    is meaningful only if the lwp is in a PR_SYSENTRY stop or
1390                    is marked PR_ASLEEP; it instructs the lwp to abort
1391                    execution of the system call (see PCSENTRY and PCSEXIT).
1392 
1393 
1394        PRSTOP
1395                    directs the lwp to stop again as soon as possible after
1396                    resuming execution (see PCDSTOP). In particular, if the lwp
1397                    is stopped on PR_SIGNALLED or PR_FAULTED, the next stop
1398                    will show PR_REQUESTED, no other stop will have intervened,
1399                    and the lwp will not have executed any user-level code.
1400 
1401 
1402 
1403        When applied to an lwp control file, PCRUN clears any outstanding
1404        directed-stop request and makes the specific lwp runnable. The
1405        operation fails with EBUSY if the specific lwp is not stopped on an
1406        event of interest or has not been directed to stop or if the agent lwp
1407        exists and this is not the agent lwp (see PCAGENT).
1408 
1409 
1410        When applied to the process control file, a representative lwp is
1411        chosen for the operation as described for /proc/pid/status. The
1412        operation fails with EBUSY if the representative lwp is not stopped on
1413        an event of interest or has not been directed to stop or if the agent
1414        lwp exists.  If PRSTEP or PRSTOP was requested, the representative lwp
1415        is made runnable and its outstanding directed-stop request is cleared;
1416        otherwise all outstanding directed-stop requests are cleared and, if it
1417        was stopped on an event of interest, the representative lwp is marked
1418        PR_REQUESTED. If, as a consequence, all lwps are in the PR_REQUESTED or
1419        PR_SUSPENDED stop state, all lwps showing PR_REQUESTED are made
1420        runnable.
1421 
1422    PCSTRACE
1423        Define a set of signals to be traced in the process. The receipt of one
1424        of these signals by an lwp causes the lwp to stop. The set of signals
1425        is defined using an operand sigset_t contained in the control message.
1426        Receipt of SIGKILL cannot be traced; if specified, it is silently
1427        ignored.
1428 
1429 
1430        If a signal that is included in an lwp's held signal set (the signal
1431        mask) is sent to the lwp, the signal is not received and does not cause
1432        a stop until it is removed from the held signal set, either by the lwp
1433        itself or by setting the held signal set with PCSHOLD.
1434 
1435    PCCSIG
1436        The current signal, if any, is cleared from the specific or
1437        representative lwp.
1438 
1439    PCSSIG
1440        The current signal and its associated signal information for the
1441        specific or representative lwp are set according to the contents of the
1442        operand siginfo structure (see <sys/siginfo.h>).   If the specified
1443        signal number is zero, the current signal is cleared. The semantics of
1444        this operation are different from those of kill(2) in that the signal
1445        is delivered to the lwp immediately after execution is resumed (even if
1446        it is being blocked) and an additional PR_SIGNALLED stop does not
1447        intervene even if the signal is traced. Setting the current signal to
1448        SIGKILL terminates the process immediately.
1449 
1450    PCKILL
1451        If applied to the process control file, a signal is sent to the process
1452        with semantics identical to those of kill(2). If applied to an lwp
1453        control file, a directed signal is sent to the specific lwp. The signal
1454        is named in a long operand contained in the message. Sending SIGKILL
1455        terminates the process immediately.
1456 
1457    PCUNKILL
1458        A signal is deleted, that is, it is removed from the set of pending
1459        signals. If applied to the process control file, the signal is deleted
1460        from the process's pending signals. If applied to an lwp control file,
1461        the signal is deleted from the lwp's pending signals. The current
1462        signal (if any) is unaffected. The signal is named in a long operand in
1463        the control message. It is an error (EINVAL) to attempt to delete
1464        SIGKILL.
1465 
1466    PCSHOLD
1467        Set the set of held signals for the specific or representative lwp
1468        (signals whose delivery will be blocked if sent to the lwp). The set of
1469        signals is specified with a sigset_t operand. SIGKILL and SIGSTOP
1470        cannot be held; if specified, they are silently ignored.
1471 
1472    PCSFAULT
1473        Define a set of hardware faults to be traced in the process. On
1474        incurring one of these faults, an lwp stops. The set is defined via the
1475        operand fltset_t structure. Fault names are defined in <sys/fault.h>
1476        and include the following. Some of these may not occur on all
1477        processors; there may be processor-specific faults in addition to
1478        these.
1479 
1480        FLTILL
1481                     illegal instruction
1482 
1483 
1484        FLTPRIV
1485                     privileged instruction
1486 
1487 
1488        FLTBPT
1489                     breakpoint trap
1490 
1491 
1492        FLTTRACE
1493                     trace trap (single-step)
1494 
1495 
1496        FLTWATCH
1497                     watchpoint trap
1498 
1499 
1500        FLTACCESS
1501                     memory access fault (bus error)
1502 
1503 
1504        FLTBOUNDS
1505                     memory bounds violation
1506 
1507 
1508        FLTIOVF
1509                     integer overflow
1510 
1511 
1512        FLTIZDIV
1513                     integer zero divide
1514 
1515 
1516        FLTFPE
1517                     floating-point exception
1518 
1519 
1520        FLTSTACK
1521                     unrecoverable stack fault
1522 
1523 
1524        FLTPAGE
1525                     recoverable page fault
1526 
1527 
1528 
1529        When not traced, a fault normally results in the posting of a signal to
1530        the lwp that incurred the fault. If an lwp stops on a fault, the signal
1531        is posted to the lwp when execution is resumed unless the fault is
1532        cleared by PCCFAULT or by the PRCFAULT option of PCRUN. FLTPAGE is an
1533        exception; no signal is posted. The pr_info field in the lwpstatus
1534        structure identifies the signal to be sent and contains machine-
1535        specific information about the fault.
1536 
1537    PCCFAULT
1538        The current fault, if any, is cleared; the associated signal will not
1539        be sent to the specific or representative lwp.
1540 
1541    PCSENTRY PCSEXIT
1542        These control operations instruct the process's lwps to stop on entry
1543        to or exit from specified system calls. The set of system calls to be
1544        traced is defined via an operand sysset_t structure.
1545 
1546 
1547        When entry to a system call is being traced, an lwp stops after having
1548        begun the call to the system but before the system call arguments have
1549        been fetched from the lwp. When exit from a system call is being
1550        traced, an lwp stops on completion of the system call just prior to
1551        checking for signals and returning to user level. At this point, all
1552        return values have been stored into the lwp's registers.
1553 
1554 
1555        If an lwp is stopped on entry to a system call (PR_SYSENTRY) or when
1556        sleeping in an interruptible system call (PR_ASLEEP is set), it may be
1557        instructed to go directly to system call exit by specifying the
1558        PRSABORT flag in a PCRUN control message. Unless exit from the system
1559        call is being traced, the lwp returns to user level showing EINTR.
1560 
1561    PCWATCH
1562        Set or clear a watched area in the controlled process from a prwatch
1563        structure operand:
1564 
1565          typedef struct prwatch {
1566              uintptr_t pr_vaddr;  /* virtual address of watched area */
1567              size_t pr_size;      /* size of watched area in bytes */
1568              int pr_wflags;       /* watch type flags */
1569          } prwatch_t;
1570 
1571 
1572 
1573        pr_vaddr specifies the virtual address of an area of memory to be
1574        watched in the controlled process. pr_size specifies the size of the
1575        area, in bytes. pr_wflags specifies the type of memory access to be
1576        monitored as a bit-mask of the following flags:
1577 
1578        WA_READ
1579                        read access
1580 
1581 
1582        WA_WRITE
1583                        write access
1584 
1585 
1586        WA_EXEC
1587                        execution access
1588 
1589 
1590        WA_TRAPAFTER
1591                        trap after the instruction completes
1592 
1593 
1594 
1595        If pr_wflags is non-empty, a watched area is established for the
1596        virtual address range specified by pr_vaddr and pr_size. If pr_wflags
1597        is empty, any previously-established watched area starting at the
1598        specified virtual address is cleared; pr_size is ignored.
1599 
1600 
1601        A watchpoint is triggered when an lwp in the traced process makes a
1602        memory reference that covers at least one byte of a watched area and
1603        the memory reference is as specified in pr_wflags. When an lwp triggers
1604        a watchpoint, it incurs a watchpoint trap. If FLTWATCH is being traced,
1605        the lwp stops; otherwise, it is sent a SIGTRAP signal; if SIGTRAP is
1606        being traced and is not blocked, the lwp stops.
1607 
1608 
1609        The watchpoint trap occurs before the instruction completes unless
1610        WA_TRAPAFTER was specified, in which case it occurs after the
1611        instruction completes. If it occurs before completion, the memory is
1612        not modified. If it occurs after completion, the memory is modified (if
1613        the access is a write access).
1614 
1615 
1616        Physical i/o is an exception for watchpoint traps. In this instance,
1617        there is no guarantee that memory before the watched area has already
1618        been modified (or in the case of WA_TRAPAFTER, that the memory
1619        following the watched area has not been modified) when the watchpoint
1620        trap occurs and the lwp stops.
1621 
1622 
1623        pr_info in the lwpstatus structure contains information pertinent to
1624        the watchpoint trap. In particular, the si_addr field contains the
1625        virtual address of the memory reference that triggered the watchpoint,
1626        and the si_code field contains one of TRAP_RWATCH, TRAP_WWATCH, or
1627        TRAP_XWATCH, indicating read, write, or execute access, respectively.
1628        The si_trapafter field is zero unless WA_TRAPAFTER is in effect for
1629        this watched area; non-zero indicates that the current instruction is
1630        not the instruction that incurred the watchpoint trap. The si_pc field
1631        contains the virtual address of the instruction that incurred the trap.
1632 
1633 
1634        A watchpoint trap may be triggered while executing a system call that
1635        makes reference to the traced process's memory. The lwp that is
1636        executing the system call incurs the watchpoint trap while still in the
1637        system call. If it stops as a result, the lwpstatus structure contains
1638        the system call number and its arguments. If the lwp does not stop, or
1639        if it is set running again without clearing the signal or fault, the
1640        system call fails with EFAULT. If WA_TRAPAFTER was specified, the
1641        memory reference will have completed and the memory will have been
1642        modified (if the access was a write access) when the watchpoint trap
1643        occurs.
1644 
1645 
1646        If more than one of WA_READ, WA_WRITE, and WA_EXEC is specified for a
1647        watched area, and a single instruction incurs more than one of the
1648        specified types, only one is reported when the watchpoint trap occurs.
1649        The precedence is WA_EXEC, WA_READ, WA_WRITE (WA_EXEC and WA_READ take
1650        precedence over WA_WRITE), unless WA_TRAPAFTER was specified, in which
1651        case it is WA_WRITE, WA_READ, WA_EXEC (WA_WRITE takes precedence).
1652 
1653 
1654        PCWATCH fails with EINVAL if an attempt is made to specify overlapping
1655        watched areas or if pr_wflags contains flags other than those specified
1656        above. It fails with ENOMEM if an attempt is made to establish more
1657        watched areas than the system can support (the system can support
1658        thousands).
1659 
1660 
1661        The child of a vfork(2) borrows the parent's address space. When a
1662        vfork(2) is executed by a traced process, all watched areas established
1663        for the parent are suspended until the child terminates or performs an
1664        exec(2). Any watched areas established independently in the child are
1665        cancelled when the parent resumes after the child's termination or
1666        exec(2). PCWATCH fails with EBUSY if applied to the parent of a
1667        vfork(2) before the child has terminated or performed an exec(2).  The
1668        PR_VFORKP flag is set in the pstatus structure for such a parent
1669        process.
1670 
1671 
1672        Certain accesses of the traced process's address space by the operating
1673        system are immune to watchpoints. The initial construction of a signal
1674        stack frame when a signal is delivered to an lwp will not trigger a
1675        watchpoint trap even if the new frame covers watched areas of the
1676        stack. Once the signal handler is entered, watchpoint traps occur
1677        normally. On SPARC based machines, register window overflow and
1678        underflow will not trigger watchpoint traps, even if the register
1679        window save areas cover watched areas of the stack.
1680 
1681 
1682        Watched areas are not inherited by child processes, even if the traced
1683        process's inherit-on-fork mode, PR_FORK, is set (see PCSET, below).
1684        All watched areas are cancelled when the traced process performs a
1685        successful exec(2).
1686 
1687    PCSET PCUNSET
1688        PCSET sets one or more modes of operation for the traced process.
1689        PCUNSET unsets these modes. The modes to be set or unset are specified
1690        by flags in an operand long in the control message:
1691 
1692        PR_FORK
1693                     (inherit-on-fork): When set, the process's tracing flags
1694                     and its inherit-on-fork mode are inherited by the child of
1695                     a fork(2), fork1(2), or vfork(2). When unset, child
1696                     processes start with all tracing flags cleared.
1697 
1698 
1699        PR_RLC
1700                     (run-on-last-close): When set and the last writable /proc
1701                     file descriptor referring to the traced process or any of
1702                     its lwps is closed, all of the process's tracing flags and
1703                     watched areas are cleared, any outstanding stop directives
1704                     are canceled, and if any lwps are stopped on events of
1705                     interest, they are set running as though PCRUN had been
1706                     applied to them. When unset, the process's tracing flags
1707                     and watched areas are retained and lwps are not set
1708                     running on last close.
1709 
1710 
1711        PR_KLC
1712                     (kill-on-last-close): When set and the last writable /proc
1713                     file descriptor referring to the traced process or any of
1714                     its lwps is closed, the process is terminated with
1715                     SIGKILL.
1716 
1717 
1718        PR_ASYNC
1719                     (asynchronous-stop): When set, a stop on an event of
1720                     interest by one lwp does not directly affect any other lwp
1721                     in the process. When unset and an lwp stops on an event of
1722                     interest other than PR_REQUESTED, all other lwps in the
1723                     process are directed to stop.
1724 
1725 
1726        PR_MSACCT
1727                     (microstate accounting): Microstate accounting is now
1728                     continuously enabled.  This flag is deprecated and no
1729                     longer has any effect upon microstate accounting.
1730                     Applications may toggle this flag; however, microstate
1731                     accounting will remain enabled regardless.
1732 
1733 
1734        PR_MSFORK
1735                     (inherit microstate accounting): All processes now inherit
1736                     microstate accounting, as it is continuously enabled. This
1737                     flag has been deprecated and its use no longer has any
1738                     effect upon the behavior of microstate accounting.
1739 
1740 
1741        PR_BPTADJ
1742                     (breakpoint trap pc adjustment): On x86-based machines, a
1743                     breakpoint trap leaves the program counter (the EIP)
1744                     referring to the breakpointed instruction plus one byte.
1745                     When PR_BPTADJ is set, the system will adjust the program
1746                     counter back to the location of the breakpointed
1747                     instruction when the lwp stops on a breakpoint. This flag
1748                     has no effect on SPARC based machines, where breakpoint
1749                     traps leave the program counter referring to the
1750                     breakpointed instruction.
1751 
1752 
1753        PR_PTRACE
1754                     (ptrace-compatibility): When set, a stop on an event of
1755                     interest by the traced process is reported to the parent
1756                     of the traced process by wait(3C), SIGTRAP is sent to the
1757                     traced process when it executes a successful exec(2),
1758                     setuid/setgid flags are not honored for execs performed by
1759                     the traced process, any exec of an object file that the
1760                     traced process cannot read fails, and the process dies
1761                     when its parent dies. This mode is deprecated; it is
1762                     provided only to allow ptrace(3C) to be implemented as a
1763                     library function using /proc.
1764 
1765 
1766 
1767        It is an error (EINVAL) to specify flags other than those described
1768        above or to apply these operations to a system process. The current
1769        modes are reported in the pr_flags field of /proc/pid/status and
1770        /proc/pid/lwp/lwp/lwpstatus.
1771 
1772    PCSREG
1773        Set the general registers for the specific or representative lwp
1774        according to the operand prgregset_t structure.
1775 
1776 
1777        On SPARC based systems, only the condition-code bits of the processor-
1778        status register (R_PSR) of SPARC V8 (32-bit) processes can be modified
1779        by PCSREG. Other privileged registers cannot be modified at all.
1780 
1781 
1782        On x86-based systems, only certain bits of the flags register (EFL) can
1783        be modified by PCSREG: these include the condition codes, direction-
1784        bit, and overflow-bit.
1785 
1786 
1787        PCSREG fails with EBUSY if the lwp is not stopped on an event of
1788        interest.
1789 
1790    PCSVADDR
1791        Set the address at which execution will resume for the specific or
1792        representative lwp from the operand long. On SPARC based systems, both
1793        %pc and %npc are set, with %npc set to the instruction following the
1794        virtual address. On x86-based systems, only %eip is set. PCSVADDR fails
1795        with EBUSY if the lwp is not stopped on an event of interest.
1796 
1797    PCSFPREG
1798        Set the floating-point registers for the specific or representative lwp
1799        according to the operand prfpregset_t structure. An error (EINVAL) is
1800        returned if the system does not support floating-point operations (no
1801        floating-point hardware and the system does not emulate floating-point
1802        machine instructions). PCSFPREG fails with EBUSY if the lwp is not
1803        stopped on an event of interest.
1804 
1805    PCSXREG
1806        Set the extra state registers for the specific or representative lwp
1807        according to the architecture-dependent operand prxregset_t structure.
1808        An error (EINVAL) is returned if the system does not support extra
1809        state registers. PCSXREG fails with EBUSY if the lwp is not stopped on
1810        an event of interest.
1811 
1812    PCSASRS
1813        Set the ancillary state registers for the specific or representative
1814        lwp according to the SPARC V9 platform-dependent operand asrset_t
1815        structure.  An error (EINVAL) is returned if either the target process
1816        or the controlling process is not a 64-bit SPARC V9 process. Most of
1817        the ancillary state registers are privileged registers that cannot be
1818        modified. Only those that can be modified are set; all others are
1819        silently ignored. PCSASRS fails with EBUSY if the lwp is not stopped on
1820        an event of interest.
1821 
1822    PCAGENT
1823        Create an agent lwp in the controlled process with register values from
1824        the operand prgregset_t structure (see PCSREG, above). The agent lwp is
1825        created in the stopped state showing PR_REQUESTED and with its held
1826        signal set (the signal mask) having all signals except SIGKILL and
1827        SIGSTOP blocked.
1828 
1829 
1830        The PCAGENT operation fails with EBUSY unless the process is fully
1831        stopped via /proc, that is, unless all of the lwps in the process are
1832        stopped either on events of interest or on PR_SUSPENDED, or are stopped
1833        on PR_JOBCONTROL and have been directed to stop via PCDSTOP.  It fails
1834        with EBUSY if an agent lwp already exists. It fails with ENOMEM if
1835        system resources for creating new lwps have been exhausted.
1836 
1837 
1838        Any PCRUN operation applied to the process control file or to the
1839        control file of an lwp other than the agent lwp fails with EBUSY as
1840        long as the agent lwp exists. The agent lwp must be caused to terminate
1841        by executing the SYS_lwp_exit system call trap before the process can
1842        be restarted.
1843 
1844 
1845        Once the agent lwp is created, its lwp-ID can be found by reading the
1846        process status file. To facilitate opening the agent lwp's control and
1847        status files, the directory name /propc/pid/lwp/agent is accepted for
1848        lookup operations as an invisible alias for /proc/pid/lwp/lwpid, lwpid
1849        being the lwp-ID of the agent lwp (invisible in the sense that the name
1850        ``agent'' does not appear in a directory listing of /proc/pid/lwp
1851        obtained from ls(1), getdents(2), or readdir(3C)).
1852 
1853 
1854        The purpose of the agent lwp is to perform operations in the controlled
1855        process on behalf of the controlling process: to gather information not
1856        directly available via /proc files, or in general to make the process
1857        change state in ways not directly available via /proc control
1858        operations. To make use of an agent lwp, the controlling process must
1859        be capable of making it execute system calls (specifically, the
1860        SYS_lwp_exit system call trap). The register values given to the agent
1861        lwp on creation are typically the registers of the representative lwp,
1862        so that the agent lwp can use its stack.
1863 
1864 
1865        If the controlling process neglects to force the agent lwp to execute
1866        the SYS_lwp_exit system call (due to either logic error or fatal
1867        failure on the part of the controlling process), the agent lwp will
1868        remain in the target process.  For purposes of being able to debug
1869        these otherwise rogue agents, information as to the creator of the
1870        agent lwp is reflected in that lwp's spymaster file in /proc. Should
1871        the target process generate a core dump with the agent lwp in place,
1872        this information will be available via the NT_SPYMASTER note in the
1873        core file (see core(4)).
1874 
1875 
1876        The agent lwp is not allowed to execute any variation of the SYS_fork
1877        or SYS_exec system call traps. Attempts to do so yield ENOTSUP to the
1878        agent lwp.
1879 
1880 
1881        Symbolic constants for system call trap numbers like SYS_lwp_exit and
1882        SYS_lwp_create can be found in the header file <sys/syscall.h>.
1883 
1884    PCREAD PCWRITE
1885        Read or write the target process's address space via a priovec
1886        structure operand:
1887 
1888          typedef struct priovec {
1889              void *pio_base;      /* buffer in controlling process */
1890              size_t pio_len;      /* size of read/write request in bytes */
1891              off_t pio_offset;    /* virtual address in target process */
1892          } priovec_t;
1893 
1894 
1895 
1896        These operations have the same effect as pread(2) and pwrite(2),
1897        respectively, of the target process's address space file. The
1898        difference is that more than one PCREAD or PCWRITE control operation
1899        can be written to the control file at once, and they can be
1900        interspersed with other control operations in a single write to the
1901        control file. This is useful, for example, when planting many
1902        breakpoint instructions in the process's address space, or when
1903        stepping over a breakpointed instruction. Unlike pread(2) and
1904        pwrite(2), no provision is made for partial reads or writes; if the
1905        operation cannot be performed completely, it fails with EIO.
1906 
1907    PCNICE
1908        The traced process's nice(2) value is incremented by the amount in the
1909        operand long. Only a process with the {PRIV_PROC_PRIOCNTL} privilege
1910        asserted in its effective set can better a process's priority in this
1911        way, but any user may lower the priority. This operation is not
1912        meaningful for all scheduling classes.
1913 
1914    PCSCRED
1915        Set the target process credentials to the values contained in the
1916        prcred_t structure operand (see /proc/pid/cred). The effective, real,
1917        and saved user-IDs and group-IDs of the target process are set. The
1918        target process's supplementary groups are not changed; the pr_ngroups
1919        and pr_groups members of the structure operand are ignored. Only the
1920        privileged processes can perform this operation; for all others it
1921        fails with EPERM.
1922 
1923    PCSCREDX
1924        Operates like PCSCRED but also sets the supplementary groups; the
1925        length of the data written with this control operation should be
1926        "sizeof (prcred_t) + sizeof (gid_t) * (#groups - 1)".
1927 
1928    PCSPRIV
1929        Set the target process privilege to the values contained in the
1930        prpriv_t operand (see /proc/pid/priv). The effective, permitted,
1931        inheritable, and limit sets are all changed. Privilege flags can also
1932        be set. The process is made privilege aware unless it can relinquish
1933        privilege awareness. See privileges(5).
1934 
1935 
1936        The limit set of the target process cannot be grown. The other
1937        privilege sets must be subsets of the intersection of the effective set
1938        of the calling process with the new limit set of the target process or
1939        subsets of the original values of the sets in the target process.
1940 
1941 
1942        If any of the above restrictions are not met, EPERM is returned. If the
1943        structure written is improperly formatted, EINVAL is returned.
1944 
1945 PROGRAMMING NOTES
1946        For security reasons, except for the psinfo, usage, lpsinfo, lusage,
1947        lwpsinfo, and lwpusage files, which are world-readable, and except for
1948        privileged processes, an open of a /proc file fails unless both the
1949        user-ID and group-ID of the caller match those of the traced process
1950        and the process's object file is readable by the caller. The effective
1951        set of the caller is a superset of both the inheritable and the
1952        permitted set of the target process. The limit set of the caller is a
1953        superset of the limit set of the target process. Except for the world-
1954        readable files just mentioned, files corresponding to setuid and setgid
1955        processes can be opened only by the appropriately privileged process.
1956 
1957 
1958        A process that is missing the basic privilege {PRIV_PROC_INFO} cannot
1959        see any processes under /proc that it cannot send a signal to.
1960 
1961 
1962        A process that has {PRIV_PROC_OWNER} asserted in its effective set can
1963        open any file for reading. To manipulate or control a process, the
1964        controlling process must have at least as many privileges in its
1965        effective set as the target process has in its effective, inheritable,
1966        and permitted sets. The limit set of the controlling process must be a
1967        superset of the limit set of the target process. Additional
1968        restrictions apply if any of the uids of the target process are 0. See
1969        privileges(5).
1970 
1971 
1972        Even if held by a privileged process, an open process or lwp file
1973        descriptor (other than file descriptors for the world-readable files)
1974        becomes invalid if the traced process performs an exec(2) of a
1975        setuid/setgid object file or an object file that the traced process
1976        cannot read. Any operation performed on an invalid file descriptor,
1977        except close(2), fails with EAGAIN. In this situation, if any tracing
1978        flags are set and the process or any lwp file descriptor is open for
1979        writing, the process will have been directed to stop and its run-on-
1980        last-close flag will have been set (see PCSET). This enables a
1981        controlling process (if it has permission) to reopen the /proc files to
1982        get new valid file descriptors, close the invalid file descriptors,
1983        unset the run-on-last-close flag (if desired), and proceed. Just
1984        closing the invalid file descriptors causes the traced process to
1985        resume execution with all tracing flags cleared. Any process not
1986        currently open for writing via /proc, but that has left-over tracing
1987        flags from a previous open, and that executes a setuid/setgid or
1988        unreadable object file, will not be stopped but will have all its
1989        tracing flags cleared.
1990 
1991 
1992        To wait for one or more of a set of processes or lwps to stop or
1993        terminate, /proc file descriptors (other than those obtained by opening
1994        the cwd or root directories or by opening files in the fd or object
1995        directories) can be used in a poll(2) system call. When requested and
1996        returned, either of the polling events POLLPRI or POLLWRNORM indicates
1997        that the process or lwp stopped on an event of interest. Although they
1998        cannot be requested, the polling events POLLHUP, POLLERR, and POLLNVAL
1999        may be returned. POLLHUP indicates that the process or lwp has
2000        terminated. POLLERR indicates that the file descriptor has become
2001        invalid. POLLNVAL is returned immediately if POLLPRI or POLLWRNORM is
2002        requested on a file descriptor referring to a system process (see
2003        PCSTOP). The requested events may be empty to wait simply for
2004        termination.
2005 
2006 FILES
2007        /proc
2008 
2009            directory (list of processes)
2010 
2011 
2012        /proc/pid
2013 
2014            specific process directory
2015 
2016 
2017        /proc/self
2018 
2019            alias for a process's own directory
2020 
2021 
2022        /proc/pid/as
2023 
2024            address space file
2025 
2026 
2027        /proc/pid/ctl
2028 
2029            process control file
2030 
2031 
2032        /proc/pid/status
2033 
2034            process status
2035 
2036 
2037        /proc/pid/lstatus
2038 
2039            array of lwp status structs
2040 
2041 
2042        /proc/pid/psinfo
2043 
2044            process ps(1) info
2045 
2046 
2047        /proc/pid/lpsinfo
2048 
2049            array of lwp ps(1) info structs
2050 
2051 
2052        /proc/pid/map
2053 
2054            address space map
2055 
2056 
2057        /proc/pid/xmap
2058 
2059            extended address space map
2060 
2061 
2062        /proc/pid/rmap
2063 
2064            reserved address map
2065 
2066 
2067        /proc/pid/cred
2068 
2069            process credentials
2070 
2071 
2072        /proc/pid/priv
2073 
2074            process privileges
2075 
2076 
2077        /proc/pid/sigact
2078 
2079            process signal actions
2080 
2081 
2082        /proc/pid/auxv
2083 
2084            process aux vector
2085 
2086 
2087        /proc/pid/ldt
2088 
2089            process LDT (x86 only)
2090 
2091 
2092        /proc/pid/usage
2093 
2094            process usage
2095 
2096 
2097        /proc/pid/lusage
2098 
2099            array of lwp usage structs
2100 
2101 
2102        /proc/pid/path
2103 
2104            symbolic links to process open files
2105 
2106 
2107        /proc/pid/pagedata
2108 
2109            process page data
2110 
2111 
2112        /proc/pid/watch
2113 
2114            active watchpoints
2115 
2116 
2117        /proc/pid/cwd
2118 
2119            alias for the current working directory
2120 
2121 
2122        /proc/pid/root
2123 
2124            alias for the root directory
2125 
2126 
2127        /proc/pid/fd
2128 
2129            directory (list of open files)
2130 
2131 
2132        /proc/pid/fd/*
2133 
2134            aliases for process's open files
2135 
2136 
2137        /proc/pid/object
2138 
2139            directory (list of mapped files)
2140 
2141 
2142        /proc/pid/object/a.out
2143 
2144            alias for process's executable file
2145 
2146 
2147        /proc/pid/object/*
2148 
2149            aliases for other mapped files
2150 
2151 
2152        /proc/pid/lwp
2153 
2154            directory (list of lwps)
2155 
2156 
2157        /proc/pid/lwp/lwpid
2158 
2159            specific lwp directory
2160 
2161 
2162        /proc/pid/lwp/agent
2163 
2164            alias for the agent lwp directory
2165 
2166 
2167        /proc/pid/lwp/lwpid/lwpctl
2168 
2169            lwp control file
2170 
2171 
2172        /proc/pid/lwp/lwpid/lwpstatus
2173 
2174            lwp status
2175 
2176 
2177        /proc/pid/lwp/lwpid/lwpsinfo
2178 
2179            lwp ps(1) info
2180 
2181 
2182        /proc/pid/lwp/lwpid/lwpusage
2183 
2184            lwp usage
2185 
2186 
2187        /proc/pid/lwp/lwpid/gwindows
2188 
2189            register windows (SPARC only)
2190 
2191 
2192        /proc/pid/lwp/lwpid/xregs
2193 
2194            extra state registers
2195 
2196 
2197        /proc/pid/lwp/lwpid/asrs
2198 
2199            ancillary state registers (SPARC V9 only)
2200 
2201 
2202        /proc/pid/lwp/lwpid/spymaster
2203 
2204            For an agent LWP, the controlling process
2205 
2206 
2207 SEE ALSO
2208        ls(1), ps(1), chroot(1M), alarm(2), brk(2), chdir(2), chroot(2),
2209        close(2), creat(2), dup(2), exec(2), fcntl(2), fork(2), fork1(2),
2210        fstat(2), getdents(2), getustack(2), kill(2), lseek(2), mmap(2),
2211        nice(2), open(2), poll(2), pread(2), ptrace(3C), pwrite(2), read(2),
2212        readlink(2), readv(2), shmget(2), sigaction(2), sigaltstack(2),
2213        vfork(2), write(2), writev(2), _stack_grow(3C), readdir(3C),
2214        pthread_create(3C), pthread_join(3C), siginfo.h(3HEAD),
2215        signal.h(3HEAD), thr_create(3C), thr_join(3C), types32.h(3HEAD),
2216        ucontext.h(3HEAD), wait(3C), contract(4), core(4), process(4),
2217        lfcompile(5), privileges(5), security-flags(5)
2218 
2219 DIAGNOSTICS
2220        Errors that can occur in addition to the errors normally associated
2221        with file system access:
2222 
2223        E2BIG
2224                     Data to be returned in a read(2) of the page data file
2225                     exceeds the size of the read buffer provided by the
2226                     caller.
2227 
2228 
2229        EACCES
2230                     An attempt was made to examine a process that ran under a
2231                     different uid than the controlling process and
2232                     {PRIV_PROC_OWNER} was not asserted in the effective set.
2233 
2234 
2235        EAGAIN
2236                     The traced process has performed an exec(2) of a
2237                     setuid/setgid object file or of an object file that it
2238                     cannot read; all further operations on the process or lwp
2239                     file descriptor (except close(2)) elicit this error.
2240 
2241 
2242        EBUSY
2243                     PCSTOP, PCDSTOP, PCWSTOP, or PCTWSTOP was applied to a
2244                     system process; an exclusive open(2) was attempted on a
2245                     /proc file for a process already open for writing; PCRUN,
2246                     PCSREG, PCSVADDR, PCSFPREG, or PCSXREG was applied to a
2247                     process or lwp not stopped on an event of interest; an
2248                     attempt was made to mount /proc when it was already
2249                     mounted; PCAGENT was applied to a process that was not
2250                     fully stopped or that already had an agent lwp.
2251 
2252 
2253        EINVAL
2254                     In general, this means that some invalid argument was
2255                     supplied to a system call. A non-exhaustive list of
2256                     conditions eliciting this error includes: a control
2257                     message operation code is undefined; an out-of-range
2258                     signal number was specified with PCSSIG, PCKILL, or
2259                     PCUNKILL; SIGKILL was specified with PCUNKILL; PCSFPREG
2260                     was applied on a system that does not support floating-
2261                     point operations; PCSXREG was applied on a system that
2262                     does not support extra state registers.
2263 
2264 
2265        EINTR
2266                     A signal was received by the controlling process while
2267                     waiting for the traced process or lwp to stop via PCSTOP,
2268                     PCWSTOP, or PCTWSTOP.
2269 
2270 
2271        EIO
2272                     A write(2) was attempted at an illegal address in the
2273                     traced process.
2274 
2275 
2276        ENOENT
2277                     The traced process or lwp has terminated after being
2278                     opened. The basic privilege {PRIV_PROC_INFO} is not
2279                     asserted in the effective set of the calling process and
2280                     the calling process cannot send a signal to the target
2281                     process.
2282 
2283 
2284        ENOMEM
2285                     The system-imposed limit on the number of page data file
2286                     descriptors was reached on an open of /proc/pid/pagedata;
2287                     an attempt was made with PCWATCH to establish more watched
2288                     areas than the system can support; the PCAGENT operation
2289                     was issued when the system was out of resources for
2290                     creating lwps.
2291 
2292 
2293        ENOSYS
2294                     An attempt was made to perform an unsupported operation
2295                     (such as creat(2), link(2), or unlink(2)) on an entry in
2296                     /proc.
2297 
2298 
2299        EOVERFLOW
2300                     A 32-bit controlling process attempted to read or write
2301                     the as file or attempted to read the map, rmap, or
2302                     pagedata file of a 64-bit target process. A 32-bit
2303                     controlling process attempted to apply one of the control
2304                     operations PCSREG, PCSXREG, PCSVADDR, PCWATCH, PCAGENT,
2305                     PCREAD, PCWRITE to a 64-bit target process.
2306 
2307 
2308        EPERM
2309                     The process that issued the PCSCRED or PCSCREDX operation
2310                     did not have the {PRIV_PROC_SETID} privilege asserted in
2311                     its effective set, or the process that issued the PCNICE
2312                     operation did not have the {PRIV_PROC_PRIOCNTL} in its
2313                     effective set.
2314 
2315                     An attempt was made to control a process of which the E,
2316                     P, and I privilege sets were not a subset of the effective
2317                     set of the controlling process or the limit set of the
2318                     controlling process is not a superset of limit set of the
2319                     controlled process.
2320 
2321                     Any of the uids of the target process are 0 or an attempt
2322                     was made to change any of the uids to 0 using PCSCRED and
2323                     the security policy imposed additional restrictions. See
2324                     privileges(5).
2325 
2326 
2327 NOTES
2328        Descriptions of structures in this document include only interesting
2329        structure elements, not filler and padding fields, and may show
2330        elements out of order for descriptive clarity. The actual structure
2331        definitions are contained in <procfs.h>.
2332 
2333 BUGS
2334        Because the old ioctl(2)-based version of /proc is currently supported
2335        for binary compatibility with old applications, the top-level directory
2336        for a process, /proc/pid, is not world-readable, but it is world-
2337        searchable. Thus, anyone can open /proc/pid/psinfo even though ls(1)
2338        applied to /proc/pid will fail for anyone but the owner or an
2339        appropriately privileged process. Support for the old ioctl(2)-based
2340        version of /proc will be dropped in a future release, at which time the
2341        top-level directory for a process will be made world-readable.
2342 
2343 
2344        On SPARC based machines, the types gregset_t and fpregset_t defined in
2345        <sys/regset.h> are similar to but not the same as the types prgregset_t
2346        and prfpregset_t defined in <procfs.h>.
2347 
2348 
2349 
2350                                 August 22, 2018                        PROC(4)