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Code review comments from jeffpc
7029 want per-process exploit mitigation features (secflags)
7030 want basic address space layout randomization (aslr)
7031 noexec_user_stack should be a secflag
7032 want a means to forbid mappings around NULL.
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--- old/usr/src/uts/common/os/fork.c
+++ new/usr/src/uts/common/os/fork.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21
22 22 /*
23 23 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
24 24 * Copyright 2013, Joyent, Inc. All rights reserved.
25 25 */
26 26
27 27 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
28 28 /* All Rights Reserved */
29 29
30 30 #include <sys/types.h>
31 31 #include <sys/param.h>
32 32 #include <sys/sysmacros.h>
33 33 #include <sys/signal.h>
34 34 #include <sys/cred.h>
35 35 #include <sys/policy.h>
36 36 #include <sys/user.h>
37 37 #include <sys/systm.h>
38 38 #include <sys/cpuvar.h>
39 39 #include <sys/vfs.h>
40 40 #include <sys/vnode.h>
41 41 #include <sys/file.h>
42 42 #include <sys/errno.h>
43 43 #include <sys/time.h>
44 44 #include <sys/proc.h>
45 45 #include <sys/cmn_err.h>
46 46 #include <sys/acct.h>
47 47 #include <sys/tuneable.h>
48 48 #include <sys/class.h>
49 49 #include <sys/kmem.h>
50 50 #include <sys/session.h>
51 51 #include <sys/ucontext.h>
52 52 #include <sys/stack.h>
53 53 #include <sys/procfs.h>
54 54 #include <sys/prsystm.h>
55 55 #include <sys/vmsystm.h>
56 56 #include <sys/vtrace.h>
57 57 #include <sys/debug.h>
58 58 #include <sys/shm_impl.h>
59 59 #include <sys/door_data.h>
60 60 #include <vm/as.h>
61 61 #include <vm/rm.h>
62 62 #include <c2/audit.h>
63 63 #include <sys/var.h>
64 64 #include <sys/schedctl.h>
65 65 #include <sys/utrap.h>
66 66 #include <sys/task.h>
67 67 #include <sys/resource.h>
68 68 #include <sys/cyclic.h>
69 69 #include <sys/lgrp.h>
70 70 #include <sys/rctl.h>
71 71 #include <sys/contract_impl.h>
72 72 #include <sys/contract/process_impl.h>
73 73 #include <sys/list.h>
74 74 #include <sys/dtrace.h>
75 75 #include <sys/pool.h>
76 76 #include <sys/zone.h>
77 77 #include <sys/sdt.h>
78 78 #include <sys/class.h>
79 79 #include <sys/corectl.h>
80 80 #include <sys/brand.h>
81 81 #include <sys/fork.h>
82 82
83 83 static int64_t cfork(int, int, int);
84 84 static int getproc(proc_t **, pid_t, uint_t);
85 85 #define GETPROC_USER 0x0
86 86 #define GETPROC_KERNEL 0x1
87 87
88 88 static void fork_fail(proc_t *);
89 89 static void forklwp_fail(proc_t *);
90 90
91 91 int fork_fail_pending;
92 92
93 93 extern struct kmem_cache *process_cache;
94 94
95 95 /*
96 96 * The vfork() system call trap is no longer invoked by libc.
97 97 * It is retained only for the benefit of applications running
98 98 * within a solaris10 branded zone. It should be eliminated
99 99 * when we no longer support solaris10 branded zones.
100 100 */
101 101 int64_t
102 102 vfork(void)
103 103 {
104 104 curthread->t_post_sys = 1; /* so vfwait() will be called */
105 105 return (cfork(1, 1, 0));
106 106 }
107 107
108 108 /*
109 109 * forksys system call - forkx, forkallx, vforkx. This is the
110 110 * interface invoked by libc for fork1(), forkall(), and vfork()
111 111 */
112 112 int64_t
113 113 forksys(int subcode, int flags)
114 114 {
115 115 switch (subcode) {
116 116 case 0:
117 117 return (cfork(0, 1, flags)); /* forkx(flags) */
118 118 case 1:
119 119 return (cfork(0, 0, flags)); /* forkallx(flags) */
120 120 case 2:
121 121 curthread->t_post_sys = 1; /* so vfwait() will be called */
122 122 return (cfork(1, 1, flags)); /* vforkx(flags) */
123 123 default:
124 124 return ((int64_t)set_errno(EINVAL));
125 125 }
126 126 }
127 127
128 128 /* ARGSUSED */
129 129 static int64_t
130 130 cfork(int isvfork, int isfork1, int flags)
131 131 {
132 132 proc_t *p = ttoproc(curthread);
133 133 struct as *as;
134 134 proc_t *cp, **orphpp;
135 135 klwp_t *clone;
136 136 kthread_t *t;
137 137 task_t *tk;
138 138 rval_t r;
139 139 int error;
140 140 int i;
141 141 rctl_set_t *dup_set;
142 142 rctl_alloc_gp_t *dup_gp;
143 143 rctl_entity_p_t e;
144 144 lwpdir_t *ldp;
145 145 lwpent_t *lep;
146 146 lwpent_t *clep;
147 147
148 148 /*
149 149 * Allow only these two flags.
150 150 */
151 151 if ((flags & ~(FORK_NOSIGCHLD | FORK_WAITPID)) != 0) {
152 152 error = EINVAL;
153 153 atomic_inc_32(&curproc->p_zone->zone_ffmisc);
154 154 goto forkerr;
155 155 }
156 156
157 157 /*
158 158 * fork is not supported for the /proc agent lwp.
159 159 */
160 160 if (curthread == p->p_agenttp) {
161 161 error = ENOTSUP;
162 162 atomic_inc_32(&curproc->p_zone->zone_ffmisc);
163 163 goto forkerr;
164 164 }
165 165
166 166 if ((error = secpolicy_basic_fork(CRED())) != 0) {
167 167 atomic_inc_32(&p->p_zone->zone_ffmisc);
168 168 goto forkerr;
169 169 }
170 170
171 171 /*
172 172 * If the calling lwp is doing a fork1() then the
173 173 * other lwps in this process are not duplicated and
174 174 * don't need to be held where their kernel stacks can be
175 175 * cloned. If doing forkall(), the process is held with
176 176 * SHOLDFORK, so that the lwps are at a point where their
177 177 * stacks can be copied which is on entry or exit from
178 178 * the kernel.
179 179 */
180 180 if (!holdlwps(isfork1 ? SHOLDFORK1 : SHOLDFORK)) {
181 181 aston(curthread);
182 182 error = EINTR;
183 183 atomic_inc_32(&p->p_zone->zone_ffmisc);
184 184 goto forkerr;
185 185 }
186 186
187 187 #if defined(__sparc)
188 188 /*
189 189 * Ensure that the user stack is fully constructed
190 190 * before creating the child process structure.
191 191 */
192 192 (void) flush_user_windows_to_stack(NULL);
193 193 #endif
194 194
195 195 mutex_enter(&p->p_lock);
196 196 /*
197 197 * If this is vfork(), cancel any suspend request we might
198 198 * have gotten from some other thread via lwp_suspend().
199 199 * Otherwise we could end up with a deadlock on return
200 200 * from the vfork() in both the parent and the child.
201 201 */
202 202 if (isvfork)
203 203 curthread->t_proc_flag &= ~TP_HOLDLWP;
204 204 /*
205 205 * Prevent our resource set associations from being changed during fork.
206 206 */
207 207 pool_barrier_enter();
208 208 mutex_exit(&p->p_lock);
209 209
210 210 /*
211 211 * Create a child proc struct. Place a VN_HOLD on appropriate vnodes.
212 212 */
213 213 if (getproc(&cp, 0, GETPROC_USER) < 0) {
214 214 mutex_enter(&p->p_lock);
215 215 pool_barrier_exit();
216 216 continuelwps(p);
217 217 mutex_exit(&p->p_lock);
218 218 error = EAGAIN;
219 219 goto forkerr;
220 220 }
221 221
222 222 TRACE_2(TR_FAC_PROC, TR_PROC_FORK, "proc_fork:cp %p p %p", cp, p);
223 223
224 224 /*
225 225 * Assign an address space to child
226 226 */
227 227 if (isvfork) {
228 228 /*
229 229 * Clear any watched areas and remember the
230 230 * watched pages for restoring in vfwait().
231 231 */
232 232 as = p->p_as;
233 233 if (avl_numnodes(&as->a_wpage) != 0) {
234 234 AS_LOCK_ENTER(as, RW_WRITER);
235 235 as_clearwatch(as);
236 236 p->p_wpage = as->a_wpage;
237 237 avl_create(&as->a_wpage, wp_compare,
238 238 sizeof (struct watched_page),
239 239 offsetof(struct watched_page, wp_link));
240 240 AS_LOCK_EXIT(as);
241 241 }
242 242 cp->p_as = as;
243 243 cp->p_flag |= SVFORK;
244 244
245 245 /*
246 246 * Use the parent's shm segment list information for
247 247 * the child as it uses its address space till it execs.
248 248 */
249 249 cp->p_segacct = p->p_segacct;
250 250 } else {
251 251 /*
252 252 * We need to hold P_PR_LOCK until the address space has
253 253 * been duplicated and we've had a chance to remove from the
254 254 * child any DTrace probes that were in the parent. Holding
255 255 * P_PR_LOCK prevents any new probes from being added and any
256 256 * extant probes from being removed.
257 257 */
258 258 mutex_enter(&p->p_lock);
259 259 sprlock_proc(p);
260 260 p->p_flag |= SFORKING;
261 261 mutex_exit(&p->p_lock);
262 262
263 263 error = as_dup(p->p_as, cp);
264 264 if (error != 0) {
265 265 mutex_enter(&p->p_lock);
266 266 sprunlock(p);
267 267 fork_fail(cp);
268 268 mutex_enter(&pidlock);
269 269 orphpp = &p->p_orphan;
270 270 while (*orphpp != cp)
271 271 orphpp = &(*orphpp)->p_nextorph;
272 272 *orphpp = cp->p_nextorph;
273 273 if (p->p_child == cp)
274 274 p->p_child = cp->p_sibling;
275 275 if (cp->p_sibling)
276 276 cp->p_sibling->p_psibling = cp->p_psibling;
277 277 if (cp->p_psibling)
278 278 cp->p_psibling->p_sibling = cp->p_sibling;
279 279 mutex_enter(&cp->p_lock);
280 280 tk = cp->p_task;
281 281 task_detach(cp);
282 282 ASSERT(cp->p_pool->pool_ref > 0);
283 283 atomic_dec_32(&cp->p_pool->pool_ref);
284 284 mutex_exit(&cp->p_lock);
285 285 pid_exit(cp, tk);
286 286 mutex_exit(&pidlock);
287 287 task_rele(tk);
288 288
289 289 mutex_enter(&p->p_lock);
290 290 p->p_flag &= ~SFORKING;
291 291 pool_barrier_exit();
292 292 continuelwps(p);
293 293 mutex_exit(&p->p_lock);
294 294 /*
295 295 * Preserve ENOMEM error condition but
296 296 * map all others to EAGAIN.
297 297 */
298 298 error = (error == ENOMEM) ? ENOMEM : EAGAIN;
299 299 atomic_inc_32(&p->p_zone->zone_ffnomem);
300 300 goto forkerr;
301 301 }
302 302
303 303 /*
304 304 * Remove all DTrace tracepoints from the child process. We
305 305 * need to do this _before_ duplicating USDT providers since
306 306 * any associated probes may be immediately enabled.
307 307 */
308 308 if (p->p_dtrace_count > 0)
309 309 dtrace_fasttrap_fork(p, cp);
310 310
311 311 mutex_enter(&p->p_lock);
312 312 sprunlock(p);
313 313
314 314 /* Duplicate parent's shared memory */
315 315 if (p->p_segacct)
316 316 shmfork(p, cp);
317 317
318 318 /*
319 319 * Duplicate any helper actions and providers. The SFORKING
320 320 * we set above informs the code to enable USDT probes that
321 321 * sprlock() may fail because the child is being forked.
322 322 */
323 323 if (p->p_dtrace_helpers != NULL) {
324 324 ASSERT(dtrace_helpers_fork != NULL);
325 325 (*dtrace_helpers_fork)(p, cp);
326 326 }
327 327
328 328 mutex_enter(&p->p_lock);
329 329 p->p_flag &= ~SFORKING;
330 330 mutex_exit(&p->p_lock);
331 331 }
332 332
333 333 /*
334 334 * Duplicate parent's resource controls.
335 335 */
336 336 dup_set = rctl_set_create();
337 337 for (;;) {
338 338 dup_gp = rctl_set_dup_prealloc(p->p_rctls);
339 339 mutex_enter(&p->p_rctls->rcs_lock);
340 340 if (rctl_set_dup_ready(p->p_rctls, dup_gp))
341 341 break;
342 342 mutex_exit(&p->p_rctls->rcs_lock);
343 343 rctl_prealloc_destroy(dup_gp);
344 344 }
345 345 e.rcep_p.proc = cp;
346 346 e.rcep_t = RCENTITY_PROCESS;
347 347 cp->p_rctls = rctl_set_dup(p->p_rctls, p, cp, &e, dup_set, dup_gp,
348 348 RCD_DUP | RCD_CALLBACK);
349 349 mutex_exit(&p->p_rctls->rcs_lock);
350 350
351 351 rctl_prealloc_destroy(dup_gp);
352 352
353 353 /*
354 354 * Allocate the child's lwp directory and lwpid hash table.
355 355 */
356 356 if (isfork1)
357 357 cp->p_lwpdir_sz = 2;
358 358 else
359 359 cp->p_lwpdir_sz = p->p_lwpdir_sz;
360 360 cp->p_lwpdir = cp->p_lwpfree = ldp =
361 361 kmem_zalloc(cp->p_lwpdir_sz * sizeof (lwpdir_t), KM_SLEEP);
362 362 for (i = 1; i < cp->p_lwpdir_sz; i++, ldp++)
363 363 ldp->ld_next = ldp + 1;
364 364 cp->p_tidhash_sz = (cp->p_lwpdir_sz + 2) / 2;
365 365 cp->p_tidhash =
366 366 kmem_zalloc(cp->p_tidhash_sz * sizeof (tidhash_t), KM_SLEEP);
367 367
368 368 /*
369 369 * Duplicate parent's lwps.
370 370 * Mutual exclusion is not needed because the process is
371 371 * in the hold state and only the current lwp is running.
372 372 */
373 373 klgrpset_clear(cp->p_lgrpset);
374 374 if (isfork1) {
375 375 clone = forklwp(ttolwp(curthread), cp, curthread->t_tid);
376 376 if (clone == NULL)
377 377 goto forklwperr;
378 378 /*
379 379 * Inherit only the lwp_wait()able flag,
380 380 * Daemon threads should not call fork1(), but oh well...
381 381 */
382 382 lwptot(clone)->t_proc_flag |=
383 383 (curthread->t_proc_flag & TP_TWAIT);
384 384 } else {
385 385 /* this is forkall(), no one can be in lwp_wait() */
386 386 ASSERT(p->p_lwpwait == 0 && p->p_lwpdwait == 0);
387 387 /* for each entry in the parent's lwp directory... */
388 388 for (i = 0, ldp = p->p_lwpdir; i < p->p_lwpdir_sz; i++, ldp++) {
389 389 klwp_t *clwp;
390 390 kthread_t *ct;
391 391
392 392 if ((lep = ldp->ld_entry) == NULL)
393 393 continue;
394 394
395 395 if ((t = lep->le_thread) != NULL) {
396 396 clwp = forklwp(ttolwp(t), cp, t->t_tid);
397 397 if (clwp == NULL)
398 398 goto forklwperr;
399 399 ct = lwptot(clwp);
400 400 /*
401 401 * Inherit lwp_wait()able and daemon flags.
402 402 */
403 403 ct->t_proc_flag |=
404 404 (t->t_proc_flag & (TP_TWAIT|TP_DAEMON));
405 405 /*
406 406 * Keep track of the clone of curthread to
407 407 * post return values through lwp_setrval().
408 408 * Mark other threads for special treatment
409 409 * by lwp_rtt() / post_syscall().
410 410 */
411 411 if (t == curthread)
412 412 clone = clwp;
413 413 else
414 414 ct->t_flag |= T_FORKALL;
415 415 } else {
416 416 /*
417 417 * Replicate zombie lwps in the child.
418 418 */
419 419 clep = kmem_zalloc(sizeof (*clep), KM_SLEEP);
420 420 clep->le_lwpid = lep->le_lwpid;
421 421 clep->le_start = lep->le_start;
422 422 lwp_hash_in(cp, clep,
423 423 cp->p_tidhash, cp->p_tidhash_sz, 0);
424 424 }
425 425 }
426 426 }
427 427
428 428 /*
429 429 * Put new process in the parent's process contract, or put it
430 430 * in a new one if there is an active process template. Send a
431 431 * fork event (if requested) to whatever contract the child is
432 432 * a member of. Fails if the parent has been SIGKILLed.
433 433 */
434 434 if (contract_process_fork(NULL, cp, p, B_TRUE) == NULL) {
435 435 atomic_inc_32(&p->p_zone->zone_ffmisc);
436 436 goto forklwperr;
437 437 }
438 438
439 439 /*
440 440 * No fork failures occur beyond this point.
441 441 */
442 442
443 443 cp->p_lwpid = p->p_lwpid;
444 444 if (!isfork1) {
445 445 cp->p_lwpdaemon = p->p_lwpdaemon;
446 446 cp->p_zombcnt = p->p_zombcnt;
447 447 /*
448 448 * If the parent's lwp ids have wrapped around, so have the
449 449 * child's.
450 450 */
451 451 cp->p_flag |= p->p_flag & SLWPWRAP;
452 452 }
453 453
454 454 mutex_enter(&p->p_lock);
455 455 corectl_path_hold(cp->p_corefile = p->p_corefile);
456 456 corectl_content_hold(cp->p_content = p->p_content);
457 457 mutex_exit(&p->p_lock);
458 458
459 459 /*
460 460 * Duplicate process context ops, if any.
461 461 */
462 462 if (p->p_pctx)
463 463 forkpctx(p, cp);
464 464
465 465 #ifdef __sparc
466 466 utrap_dup(p, cp);
467 467 #endif
468 468 /*
469 469 * If the child process has been marked to stop on exit
470 470 * from this fork, arrange for all other lwps to stop in
471 471 * sympathy with the active lwp.
472 472 */
473 473 if (PTOU(cp)->u_systrap &&
474 474 prismember(&PTOU(cp)->u_exitmask, curthread->t_sysnum)) {
475 475 mutex_enter(&cp->p_lock);
476 476 t = cp->p_tlist;
477 477 do {
478 478 t->t_proc_flag |= TP_PRSTOP;
479 479 aston(t); /* so TP_PRSTOP will be seen */
480 480 } while ((t = t->t_forw) != cp->p_tlist);
481 481 mutex_exit(&cp->p_lock);
482 482 }
483 483 /*
484 484 * If the parent process has been marked to stop on exit
485 485 * from this fork, and its asynchronous-stop flag has not
486 486 * been set, arrange for all other lwps to stop before
487 487 * they return back to user level.
488 488 */
489 489 if (!(p->p_proc_flag & P_PR_ASYNC) && PTOU(p)->u_systrap &&
490 490 prismember(&PTOU(p)->u_exitmask, curthread->t_sysnum)) {
491 491 mutex_enter(&p->p_lock);
492 492 t = p->p_tlist;
493 493 do {
494 494 t->t_proc_flag |= TP_PRSTOP;
495 495 aston(t); /* so TP_PRSTOP will be seen */
496 496 } while ((t = t->t_forw) != p->p_tlist);
497 497 mutex_exit(&p->p_lock);
498 498 }
499 499
500 500 if (PROC_IS_BRANDED(p))
501 501 BROP(p)->b_lwp_setrval(clone, p->p_pid, 1);
502 502 else
503 503 lwp_setrval(clone, p->p_pid, 1);
504 504
505 505 /* set return values for parent */
506 506 r.r_val1 = (int)cp->p_pid;
507 507 r.r_val2 = 0;
508 508
509 509 /*
510 510 * pool_barrier_exit() can now be called because the child process has:
511 511 * - all identifying features cloned or set (p_pid, p_task, p_pool)
512 512 * - all resource sets associated (p_tlist->*->t_cpupart, p_as->a_mset)
513 513 * - any other fields set which are used in resource set binding.
514 514 */
515 515 mutex_enter(&p->p_lock);
516 516 pool_barrier_exit();
517 517 mutex_exit(&p->p_lock);
518 518
519 519 mutex_enter(&pidlock);
520 520 mutex_enter(&cp->p_lock);
521 521
522 522 /*
523 523 * Set flags telling the child what (not) to do on exit.
524 524 */
525 525 if (flags & FORK_NOSIGCHLD)
526 526 cp->p_pidflag |= CLDNOSIGCHLD;
527 527 if (flags & FORK_WAITPID)
528 528 cp->p_pidflag |= CLDWAITPID;
529 529
530 530 /*
531 531 * Now that there are lwps and threads attached, add the new
532 532 * process to the process group.
533 533 */
534 534 pgjoin(cp, p->p_pgidp);
535 535 cp->p_stat = SRUN;
536 536 /*
537 537 * We are now done with all the lwps in the child process.
538 538 */
539 539 t = cp->p_tlist;
540 540 do {
541 541 /*
542 542 * Set the lwp_suspend()ed lwps running.
543 543 * They will suspend properly at syscall exit.
544 544 */
545 545 if (t->t_proc_flag & TP_HOLDLWP)
546 546 lwp_create_done(t);
547 547 else {
548 548 /* set TS_CREATE to allow continuelwps() to work */
549 549 thread_lock(t);
550 550 ASSERT(t->t_state == TS_STOPPED &&
551 551 !(t->t_schedflag & (TS_CREATE|TS_CSTART)));
552 552 t->t_schedflag |= TS_CREATE;
553 553 thread_unlock(t);
554 554 }
555 555 } while ((t = t->t_forw) != cp->p_tlist);
556 556 mutex_exit(&cp->p_lock);
557 557
558 558 if (isvfork) {
559 559 CPU_STATS_ADDQ(CPU, sys, sysvfork, 1);
560 560 mutex_enter(&p->p_lock);
561 561 p->p_flag |= SVFWAIT;
562 562 curthread->t_flag |= T_VFPARENT;
563 563 DTRACE_PROC1(create, proc_t *, cp);
564 564 cv_broadcast(&pr_pid_cv[p->p_slot]); /* inform /proc */
565 565 mutex_exit(&p->p_lock);
566 566 /*
567 567 * Grab child's p_lock before dropping pidlock to ensure
568 568 * the process will not disappear before we set it running.
569 569 */
570 570 mutex_enter(&cp->p_lock);
571 571 mutex_exit(&pidlock);
572 572 sigdefault(cp);
573 573 continuelwps(cp);
574 574 mutex_exit(&cp->p_lock);
575 575 } else {
576 576 CPU_STATS_ADDQ(CPU, sys, sysfork, 1);
577 577 DTRACE_PROC1(create, proc_t *, cp);
578 578 /*
579 579 * It is CL_FORKRET's job to drop pidlock.
580 580 * If we do it here, the process could be set running
581 581 * and disappear before CL_FORKRET() is called.
582 582 */
583 583 CL_FORKRET(curthread, cp->p_tlist);
584 584 schedctl_set_cidpri(curthread);
585 585 ASSERT(MUTEX_NOT_HELD(&pidlock));
586 586 }
587 587
588 588 return (r.r_vals);
589 589
590 590 forklwperr:
591 591 if (isvfork) {
592 592 if (avl_numnodes(&p->p_wpage) != 0) {
593 593 /* restore watchpoints to parent */
594 594 as = p->p_as;
595 595 AS_LOCK_ENTER(as, RW_WRITER);
596 596 as->a_wpage = p->p_wpage;
597 597 avl_create(&p->p_wpage, wp_compare,
598 598 sizeof (struct watched_page),
599 599 offsetof(struct watched_page, wp_link));
600 600 as_setwatch(as);
601 601 AS_LOCK_EXIT(as);
602 602 }
603 603 } else {
604 604 if (cp->p_segacct)
605 605 shmexit(cp);
606 606 as = cp->p_as;
607 607 cp->p_as = &kas;
608 608 as_free(as);
609 609 }
610 610
611 611 if (cp->p_lwpdir) {
612 612 for (i = 0, ldp = cp->p_lwpdir; i < cp->p_lwpdir_sz; i++, ldp++)
613 613 if ((lep = ldp->ld_entry) != NULL)
614 614 kmem_free(lep, sizeof (*lep));
615 615 kmem_free(cp->p_lwpdir,
616 616 cp->p_lwpdir_sz * sizeof (*cp->p_lwpdir));
617 617 }
618 618 cp->p_lwpdir = NULL;
619 619 cp->p_lwpfree = NULL;
620 620 cp->p_lwpdir_sz = 0;
621 621
622 622 if (cp->p_tidhash)
623 623 kmem_free(cp->p_tidhash,
624 624 cp->p_tidhash_sz * sizeof (*cp->p_tidhash));
625 625 cp->p_tidhash = NULL;
626 626 cp->p_tidhash_sz = 0;
627 627
628 628 forklwp_fail(cp);
629 629 fork_fail(cp);
630 630 rctl_set_free(cp->p_rctls);
631 631 mutex_enter(&pidlock);
632 632
633 633 /*
634 634 * Detach failed child from task.
635 635 */
636 636 mutex_enter(&cp->p_lock);
637 637 tk = cp->p_task;
638 638 task_detach(cp);
639 639 ASSERT(cp->p_pool->pool_ref > 0);
640 640 atomic_dec_32(&cp->p_pool->pool_ref);
641 641 mutex_exit(&cp->p_lock);
642 642
643 643 orphpp = &p->p_orphan;
644 644 while (*orphpp != cp)
645 645 orphpp = &(*orphpp)->p_nextorph;
646 646 *orphpp = cp->p_nextorph;
647 647 if (p->p_child == cp)
648 648 p->p_child = cp->p_sibling;
649 649 if (cp->p_sibling)
650 650 cp->p_sibling->p_psibling = cp->p_psibling;
651 651 if (cp->p_psibling)
652 652 cp->p_psibling->p_sibling = cp->p_sibling;
653 653 pid_exit(cp, tk);
654 654 mutex_exit(&pidlock);
655 655
656 656 task_rele(tk);
657 657
658 658 mutex_enter(&p->p_lock);
659 659 pool_barrier_exit();
660 660 continuelwps(p);
661 661 mutex_exit(&p->p_lock);
662 662 error = EAGAIN;
663 663 forkerr:
664 664 return ((int64_t)set_errno(error));
665 665 }
666 666
667 667 /*
668 668 * Free allocated resources from getproc() if a fork failed.
669 669 */
670 670 static void
671 671 fork_fail(proc_t *cp)
672 672 {
673 673 uf_info_t *fip = P_FINFO(cp);
674 674
675 675 fcnt_add(fip, -1);
676 676 sigdelq(cp, NULL, 0);
677 677
678 678 mutex_enter(&pidlock);
679 679 upcount_dec(crgetruid(cp->p_cred), crgetzoneid(cp->p_cred));
680 680 mutex_exit(&pidlock);
681 681
682 682 /*
683 683 * single threaded, so no locking needed here
684 684 */
685 685 crfree(cp->p_cred);
686 686
687 687 kmem_free(fip->fi_list, fip->fi_nfiles * sizeof (uf_entry_t));
688 688
689 689 VN_RELE(PTOU(curproc)->u_cdir);
690 690 if (PTOU(curproc)->u_rdir)
691 691 VN_RELE(PTOU(curproc)->u_rdir);
692 692 if (cp->p_exec)
693 693 VN_RELE(cp->p_exec);
694 694 if (cp->p_execdir)
695 695 VN_RELE(cp->p_execdir);
696 696 if (PTOU(curproc)->u_cwd)
697 697 refstr_rele(PTOU(curproc)->u_cwd);
698 698 if (PROC_IS_BRANDED(cp)) {
699 699 brand_clearbrand(cp, B_TRUE);
700 700 }
701 701 }
702 702
703 703 /*
704 704 * Clean up the lwps already created for this child process.
705 705 * The fork failed while duplicating all the lwps of the parent
706 706 * and those lwps already created must be freed.
707 707 * This process is invisible to the rest of the system,
708 708 * so we don't need to hold p->p_lock to protect the list.
709 709 */
710 710 static void
711 711 forklwp_fail(proc_t *p)
712 712 {
713 713 kthread_t *t;
714 714 task_t *tk;
715 715 int branded = 0;
716 716
717 717 if (PROC_IS_BRANDED(p))
718 718 branded = 1;
719 719
720 720 while ((t = p->p_tlist) != NULL) {
721 721 /*
722 722 * First remove the lwp from the process's p_tlist.
723 723 */
724 724 if (t != t->t_forw)
725 725 p->p_tlist = t->t_forw;
726 726 else
727 727 p->p_tlist = NULL;
728 728 p->p_lwpcnt--;
729 729 t->t_forw->t_back = t->t_back;
730 730 t->t_back->t_forw = t->t_forw;
731 731
732 732 tk = p->p_task;
733 733 mutex_enter(&p->p_zone->zone_nlwps_lock);
734 734 tk->tk_nlwps--;
735 735 tk->tk_proj->kpj_nlwps--;
736 736 p->p_zone->zone_nlwps--;
737 737 mutex_exit(&p->p_zone->zone_nlwps_lock);
738 738
739 739 ASSERT(t->t_schedctl == NULL);
740 740
741 741 if (branded)
742 742 BROP(p)->b_freelwp(ttolwp(t));
743 743
744 744 if (t->t_door != NULL) {
745 745 kmem_free(t->t_door, sizeof (door_data_t));
746 746 t->t_door = NULL;
747 747 }
748 748 lwp_ctmpl_clear(ttolwp(t));
749 749
750 750 /*
751 751 * Remove the thread from the all threads list.
752 752 * We need to hold pidlock for this.
753 753 */
754 754 mutex_enter(&pidlock);
755 755 t->t_next->t_prev = t->t_prev;
756 756 t->t_prev->t_next = t->t_next;
757 757 CL_EXIT(t); /* tell the scheduler that we're exiting */
758 758 cv_broadcast(&t->t_joincv); /* tell anyone in thread_join */
759 759 mutex_exit(&pidlock);
760 760
761 761 /*
762 762 * Let the lgroup load averages know that this thread isn't
763 763 * going to show up (i.e. un-do what was done on behalf of
764 764 * this thread by the earlier lgrp_move_thread()).
765 765 */
766 766 kpreempt_disable();
767 767 lgrp_move_thread(t, NULL, 1);
768 768 kpreempt_enable();
769 769
770 770 /*
771 771 * The thread was created TS_STOPPED.
772 772 * We change it to TS_FREE to avoid an
773 773 * ASSERT() panic in thread_free().
774 774 */
775 775 t->t_state = TS_FREE;
776 776 thread_rele(t);
777 777 thread_free(t);
778 778 }
779 779 }
780 780
781 781 extern struct as kas;
782 782
783 783 /*
784 784 * fork a kernel process.
785 785 */
786 786 int
787 787 newproc(void (*pc)(), caddr_t arg, id_t cid, int pri, struct contract **ct,
788 788 pid_t pid)
789 789 {
790 790 proc_t *p;
791 791 struct user *up;
792 792 kthread_t *t;
793 793 cont_process_t *ctp = NULL;
794 794 rctl_entity_p_t e;
795 795
796 796 ASSERT(cid != sysdccid);
797 797 ASSERT(cid != syscid || ct == NULL);
798 798 if (CLASS_KERNEL(cid)) {
799 799 rctl_alloc_gp_t *init_gp;
800 800 rctl_set_t *init_set;
801 801
802 802 ASSERT(pid != 1);
803 803
804 804 if (getproc(&p, pid, GETPROC_KERNEL) < 0)
805 805 return (EAGAIN);
806 806
807 807 /*
808 808 * Release the hold on the p_exec and p_execdir, these
809 809 * were acquired in getproc()
810 810 */
811 811 if (p->p_execdir != NULL)
812 812 VN_RELE(p->p_execdir);
813 813 if (p->p_exec != NULL)
814 814 VN_RELE(p->p_exec);
815 815 p->p_flag |= SNOWAIT;
816 816 p->p_exec = NULL;
817 817 p->p_execdir = NULL;
818 818
819 819 init_set = rctl_set_create();
820 820 init_gp = rctl_set_init_prealloc(RCENTITY_PROCESS);
821 821
822 822 /*
823 823 * kernel processes do not inherit /proc tracing flags.
824 824 */
825 825 sigemptyset(&p->p_sigmask);
826 826 premptyset(&p->p_fltmask);
827 827 up = PTOU(p);
828 828 up->u_systrap = 0;
829 829 premptyset(&(up->u_entrymask));
830 830 premptyset(&(up->u_exitmask));
831 831 mutex_enter(&p->p_lock);
832 832 e.rcep_p.proc = p;
833 833 e.rcep_t = RCENTITY_PROCESS;
834 834 p->p_rctls = rctl_set_init(RCENTITY_PROCESS, p, &e, init_set,
835 835 init_gp);
836 836 mutex_exit(&p->p_lock);
837 837
838 838 rctl_prealloc_destroy(init_gp);
839 839
840 840 t = lwp_kernel_create(p, pc, arg, TS_STOPPED, pri);
841 841 } else {
842 842 rctl_alloc_gp_t *init_gp, *default_gp;
843 843 rctl_set_t *init_set;
844 844 task_t *tk, *tk_old;
845 845 klwp_t *lwp;
846 846
847 847 if (getproc(&p, pid, GETPROC_USER) < 0)
848 848 return (EAGAIN);
849 849 /*
850 850 * init creates a new task, distinct from the task
851 851 * containing kernel "processes".
852 852 */
853 853 tk = task_create(0, p->p_zone);
854 854 mutex_enter(&tk->tk_zone->zone_nlwps_lock);
855 855 tk->tk_proj->kpj_ntasks++;
856 856 tk->tk_nprocs++;
857 857 mutex_exit(&tk->tk_zone->zone_nlwps_lock);
858 858
859 859 default_gp = rctl_rlimit_set_prealloc(RLIM_NLIMITS);
860 860 init_gp = rctl_set_init_prealloc(RCENTITY_PROCESS);
861 861 init_set = rctl_set_create();
862 862
863 863 mutex_enter(&pidlock);
864 864 mutex_enter(&p->p_lock);
865 865 tk_old = p->p_task; /* switch to new task */
866 866
867 867 task_detach(p);
868 868 task_begin(tk, p);
869 869 mutex_exit(&pidlock);
870 870
871 871 mutex_enter(&tk_old->tk_zone->zone_nlwps_lock);
872 872 tk_old->tk_nprocs--;
873 873 mutex_exit(&tk_old->tk_zone->zone_nlwps_lock);
874 874
875 875 e.rcep_p.proc = p;
876 876 e.rcep_t = RCENTITY_PROCESS;
877 877 p->p_rctls = rctl_set_init(RCENTITY_PROCESS, p, &e, init_set,
878 878 init_gp);
879 879 rctlproc_default_init(p, default_gp);
880 880 mutex_exit(&p->p_lock);
881 881
882 882 task_rele(tk_old);
883 883 rctl_prealloc_destroy(default_gp);
884 884 rctl_prealloc_destroy(init_gp);
885 885
886 886 if ((lwp = lwp_create(pc, arg, 0, p, TS_STOPPED, pri,
887 887 &curthread->t_hold, cid, 1)) == NULL) {
888 888 task_t *tk;
889 889 fork_fail(p);
890 890 mutex_enter(&pidlock);
891 891 mutex_enter(&p->p_lock);
892 892 tk = p->p_task;
893 893 task_detach(p);
894 894 ASSERT(p->p_pool->pool_ref > 0);
895 895 atomic_add_32(&p->p_pool->pool_ref, -1);
896 896 mutex_exit(&p->p_lock);
897 897 pid_exit(p, tk);
898 898 mutex_exit(&pidlock);
899 899 task_rele(tk);
900 900
901 901 return (EAGAIN);
902 902 }
903 903 t = lwptot(lwp);
904 904
905 905 ctp = contract_process_fork(sys_process_tmpl, p, curproc,
906 906 B_FALSE);
907 907 ASSERT(ctp != NULL);
908 908 if (ct != NULL)
909 909 *ct = &ctp->conp_contract;
910 910 }
911 911
912 912 ASSERT3U(t->t_tid, ==, 1);
913 913 p->p_lwpid = 1;
914 914 mutex_enter(&pidlock);
915 915 pgjoin(p, p->p_parent->p_pgidp);
916 916 p->p_stat = SRUN;
917 917 mutex_enter(&p->p_lock);
918 918 t->t_proc_flag &= ~TP_HOLDLWP;
919 919 lwp_create_done(t);
920 920 mutex_exit(&p->p_lock);
921 921 mutex_exit(&pidlock);
922 922 return (0);
923 923 }
924 924
925 925 /*
926 926 * create a child proc struct.
927 927 */
928 928 static int
929 929 getproc(proc_t **cpp, pid_t pid, uint_t flags)
930 930 {
931 931 proc_t *pp, *cp;
932 932 pid_t newpid;
933 933 struct user *uarea;
934 934 extern uint_t nproc;
935 935 struct cred *cr;
936 936 uid_t ruid;
937 937 zoneid_t zoneid;
938 938 task_t *task;
939 939 kproject_t *proj;
940 940 zone_t *zone;
941 941 int rctlfail = 0;
942 942
943 943 if (zone_status_get(curproc->p_zone) >= ZONE_IS_SHUTTING_DOWN)
944 944 return (-1); /* no point in starting new processes */
945 945
946 946 pp = (flags & GETPROC_KERNEL) ? &p0 : curproc;
947 947 task = pp->p_task;
948 948 proj = task->tk_proj;
949 949 zone = pp->p_zone;
950 950
951 951 mutex_enter(&pp->p_lock);
952 952 mutex_enter(&zone->zone_nlwps_lock);
953 953 if (proj != proj0p) {
954 954 if (task->tk_nprocs >= task->tk_nprocs_ctl)
955 955 if (rctl_test(rc_task_nprocs, task->tk_rctls,
956 956 pp, 1, 0) & RCT_DENY)
957 957 rctlfail = 1;
958 958
959 959 if (proj->kpj_nprocs >= proj->kpj_nprocs_ctl)
960 960 if (rctl_test(rc_project_nprocs, proj->kpj_rctls,
961 961 pp, 1, 0) & RCT_DENY)
962 962 rctlfail = 1;
963 963
964 964 if (zone->zone_nprocs >= zone->zone_nprocs_ctl)
965 965 if (rctl_test(rc_zone_nprocs, zone->zone_rctls,
966 966 pp, 1, 0) & RCT_DENY)
967 967 rctlfail = 1;
968 968
969 969 if (rctlfail) {
970 970 mutex_exit(&zone->zone_nlwps_lock);
971 971 mutex_exit(&pp->p_lock);
972 972 atomic_inc_32(&zone->zone_ffcap);
973 973 goto punish;
974 974 }
975 975 }
976 976 task->tk_nprocs++;
977 977 proj->kpj_nprocs++;
978 978 zone->zone_nprocs++;
979 979 mutex_exit(&zone->zone_nlwps_lock);
980 980 mutex_exit(&pp->p_lock);
981 981
982 982 cp = kmem_cache_alloc(process_cache, KM_SLEEP);
983 983 bzero(cp, sizeof (proc_t));
984 984
985 985 /*
986 986 * Make proc entry for child process
987 987 */
988 988 mutex_init(&cp->p_splock, NULL, MUTEX_DEFAULT, NULL);
989 989 mutex_init(&cp->p_crlock, NULL, MUTEX_DEFAULT, NULL);
990 990 mutex_init(&cp->p_pflock, NULL, MUTEX_DEFAULT, NULL);
991 991 #if defined(__x86)
992 992 mutex_init(&cp->p_ldtlock, NULL, MUTEX_DEFAULT, NULL);
993 993 #endif
994 994 mutex_init(&cp->p_maplock, NULL, MUTEX_DEFAULT, NULL);
995 995 cp->p_stat = SIDL;
996 996 cp->p_mstart = gethrtime();
997 997 cp->p_as = &kas;
998 998 /*
999 999 * p_zone must be set before we call pid_allocate since the process
1000 1000 * will be visible after that and code such as prfind_zone will
1001 1001 * look at the p_zone field.
1002 1002 */
1003 1003 cp->p_zone = pp->p_zone;
1004 1004 cp->p_t1_lgrpid = LGRP_NONE;
1005 1005 cp->p_tr_lgrpid = LGRP_NONE;
1006 1006
1007 1007 if ((newpid = pid_allocate(cp, pid, PID_ALLOC_PROC)) == -1) {
1008 1008 if (nproc == v.v_proc) {
1009 1009 CPU_STATS_ADDQ(CPU, sys, procovf, 1);
1010 1010 cmn_err(CE_WARN, "out of processes");
1011 1011 }
1012 1012 goto bad;
1013 1013 }
1014 1014
1015 1015 mutex_enter(&pp->p_lock);
1016 1016 cp->p_exec = pp->p_exec;
1017 1017 cp->p_execdir = pp->p_execdir;
1018 1018 mutex_exit(&pp->p_lock);
1019 1019
1020 1020 if (cp->p_exec) {
1021 1021 VN_HOLD(cp->p_exec);
1022 1022 /*
1023 1023 * Each VOP_OPEN() must be paired with a corresponding
1024 1024 * VOP_CLOSE(). In this case, the executable will be
1025 1025 * closed for the child in either proc_exit() or gexec().
1026 1026 */
1027 1027 if (VOP_OPEN(&cp->p_exec, FREAD, CRED(), NULL) != 0) {
1028 1028 VN_RELE(cp->p_exec);
1029 1029 cp->p_exec = NULLVP;
1030 1030 cp->p_execdir = NULLVP;
1031 1031 goto bad;
1032 1032 }
1033 1033 }
1034 1034 if (cp->p_execdir)
1035 1035 VN_HOLD(cp->p_execdir);
1036 1036
1037 1037 /*
1038 1038 * If not privileged make sure that this user hasn't exceeded
1039 1039 * v.v_maxup processes, and that users collectively haven't
1040 1040 * exceeded v.v_maxupttl processes.
1041 1041 */
1042 1042 mutex_enter(&pidlock);
1043 1043 ASSERT(nproc < v.v_proc); /* otherwise how'd we get our pid? */
1044 1044 cr = CRED();
1045 1045 ruid = crgetruid(cr);
1046 1046 zoneid = crgetzoneid(cr);
1047 1047 if (nproc >= v.v_maxup && /* short-circuit; usually false */
1048 1048 (nproc >= v.v_maxupttl ||
1049 1049 upcount_get(ruid, zoneid) >= v.v_maxup) &&
1050 1050 secpolicy_newproc(cr) != 0) {
1051 1051 mutex_exit(&pidlock);
1052 1052 zcmn_err(zoneid, CE_NOTE,
1053 1053 "out of per-user processes for uid %d", ruid);
1054 1054 goto bad;
1055 1055 }
1056 1056
1057 1057 /*
1058 1058 * Everything is cool, put the new proc on the active process list.
1059 1059 * It is already on the pid list and in /proc.
1060 1060 * Increment the per uid process count (upcount).
1061 1061 */
1062 1062 nproc++;
1063 1063 upcount_inc(ruid, zoneid);
1064 1064
1065 1065 cp->p_next = practive;
1066 1066 practive->p_prev = cp;
1067 1067 practive = cp;
1068 1068
1069 1069 cp->p_ignore = pp->p_ignore;
1070 1070 cp->p_siginfo = pp->p_siginfo;
1071 1071 cp->p_flag = pp->p_flag & (SJCTL|SNOWAIT|SNOCD);
1072 1072 cp->p_sessp = pp->p_sessp;
1073 1073 sess_hold(pp);
1074 1074 cp->p_brand = pp->p_brand;
1075 1075 if (PROC_IS_BRANDED(pp))
1076 1076 BROP(pp)->b_copy_procdata(cp, pp);
1077 1077 cp->p_bssbase = pp->p_bssbase;
1078 1078 cp->p_brkbase = pp->p_brkbase;
1079 1079 cp->p_brksize = pp->p_brksize;
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1080 1080 cp->p_brkpageszc = pp->p_brkpageszc;
1081 1081 cp->p_stksize = pp->p_stksize;
1082 1082 cp->p_stkpageszc = pp->p_stkpageszc;
1083 1083 cp->p_stkprot = pp->p_stkprot;
1084 1084 cp->p_datprot = pp->p_datprot;
1085 1085 cp->p_usrstack = pp->p_usrstack;
1086 1086 cp->p_model = pp->p_model;
1087 1087 cp->p_ppid = pp->p_pid;
1088 1088 cp->p_ancpid = pp->p_pid;
1089 1089 cp->p_portcnt = pp->p_portcnt;
1090 + /*
1091 + * Security flags are preserved on fork, the inherited copy come into
1092 + * effect on exec
1093 + */
1094 + cp->p_secflags = pp->p_secflags;
1090 1095
1091 1096 /*
1092 1097 * Initialize watchpoint structures
1093 1098 */
1094 1099 avl_create(&cp->p_warea, wa_compare, sizeof (struct watched_area),
1095 1100 offsetof(struct watched_area, wa_link));
1096 1101
1097 1102 /*
1098 1103 * Initialize immediate resource control values.
1099 1104 */
1100 1105 cp->p_stk_ctl = pp->p_stk_ctl;
1101 1106 cp->p_fsz_ctl = pp->p_fsz_ctl;
1102 1107 cp->p_vmem_ctl = pp->p_vmem_ctl;
1103 1108 cp->p_fno_ctl = pp->p_fno_ctl;
1104 1109
1105 1110 /*
1106 1111 * Link up to parent-child-sibling chain. No need to lock
1107 1112 * in general since only a call to freeproc() (done by the
1108 1113 * same parent as newproc()) diddles with the child chain.
1109 1114 */
1110 1115 cp->p_sibling = pp->p_child;
1111 1116 if (pp->p_child)
1112 1117 pp->p_child->p_psibling = cp;
1113 1118
1114 1119 cp->p_parent = pp;
1115 1120 pp->p_child = cp;
1116 1121
1117 1122 cp->p_child_ns = NULL;
1118 1123 cp->p_sibling_ns = NULL;
1119 1124
1120 1125 cp->p_nextorph = pp->p_orphan;
1121 1126 cp->p_nextofkin = pp;
1122 1127 pp->p_orphan = cp;
1123 1128
1124 1129 /*
1125 1130 * Inherit profiling state; do not inherit REALPROF profiling state.
1126 1131 */
1127 1132 cp->p_prof = pp->p_prof;
1128 1133 cp->p_rprof_cyclic = CYCLIC_NONE;
1129 1134
1130 1135 /*
1131 1136 * Inherit pool pointer from the parent. Kernel processes are
1132 1137 * always bound to the default pool.
1133 1138 */
1134 1139 mutex_enter(&pp->p_lock);
1135 1140 if (flags & GETPROC_KERNEL) {
1136 1141 cp->p_pool = pool_default;
1137 1142 cp->p_flag |= SSYS;
1138 1143 } else {
1139 1144 cp->p_pool = pp->p_pool;
1140 1145 }
1141 1146 atomic_inc_32(&cp->p_pool->pool_ref);
1142 1147 mutex_exit(&pp->p_lock);
1143 1148
1144 1149 /*
1145 1150 * Add the child process to the current task. Kernel processes
1146 1151 * are always attached to task0.
1147 1152 */
1148 1153 mutex_enter(&cp->p_lock);
1149 1154 if (flags & GETPROC_KERNEL)
1150 1155 task_attach(task0p, cp);
1151 1156 else
1152 1157 task_attach(pp->p_task, cp);
1153 1158 mutex_exit(&cp->p_lock);
1154 1159 mutex_exit(&pidlock);
1155 1160
1156 1161 avl_create(&cp->p_ct_held, contract_compar, sizeof (contract_t),
1157 1162 offsetof(contract_t, ct_ctlist));
1158 1163
1159 1164 /*
1160 1165 * Duplicate any audit information kept in the process table
1161 1166 */
1162 1167 if (audit_active) /* copy audit data to cp */
1163 1168 audit_newproc(cp);
1164 1169
1165 1170 crhold(cp->p_cred = cr);
1166 1171
1167 1172 /*
1168 1173 * Bump up the counts on the file structures pointed at by the
1169 1174 * parent's file table since the child will point at them too.
1170 1175 */
1171 1176 fcnt_add(P_FINFO(pp), 1);
1172 1177
1173 1178 if (PTOU(pp)->u_cdir) {
1174 1179 VN_HOLD(PTOU(pp)->u_cdir);
1175 1180 } else {
1176 1181 ASSERT(pp == &p0);
1177 1182 /*
1178 1183 * We must be at or before vfs_mountroot(); it will take care of
1179 1184 * assigning our current directory.
1180 1185 */
1181 1186 }
1182 1187 if (PTOU(pp)->u_rdir)
1183 1188 VN_HOLD(PTOU(pp)->u_rdir);
1184 1189 if (PTOU(pp)->u_cwd)
1185 1190 refstr_hold(PTOU(pp)->u_cwd);
1186 1191
1187 1192 /*
1188 1193 * copy the parent's uarea.
1189 1194 */
1190 1195 uarea = PTOU(cp);
1191 1196 bcopy(PTOU(pp), uarea, sizeof (*uarea));
1192 1197 flist_fork(P_FINFO(pp), P_FINFO(cp));
1193 1198
1194 1199 gethrestime(&uarea->u_start);
1195 1200 uarea->u_ticks = ddi_get_lbolt();
1196 1201 uarea->u_mem = rm_asrss(pp->p_as);
1197 1202 uarea->u_acflag = AFORK;
1198 1203
1199 1204 /*
1200 1205 * If inherit-on-fork, copy /proc tracing flags to child.
1201 1206 */
1202 1207 if ((pp->p_proc_flag & P_PR_FORK) != 0) {
1203 1208 cp->p_proc_flag |= pp->p_proc_flag & (P_PR_TRACE|P_PR_FORK);
1204 1209 cp->p_sigmask = pp->p_sigmask;
1205 1210 cp->p_fltmask = pp->p_fltmask;
1206 1211 } else {
1207 1212 sigemptyset(&cp->p_sigmask);
1208 1213 premptyset(&cp->p_fltmask);
1209 1214 uarea->u_systrap = 0;
1210 1215 premptyset(&uarea->u_entrymask);
1211 1216 premptyset(&uarea->u_exitmask);
1212 1217 }
1213 1218 /*
1214 1219 * If microstate accounting is being inherited, mark child
1215 1220 */
1216 1221 if ((pp->p_flag & SMSFORK) != 0)
1217 1222 cp->p_flag |= pp->p_flag & (SMSFORK|SMSACCT);
1218 1223
1219 1224 /*
1220 1225 * Inherit fixalignment flag from the parent
1221 1226 */
1222 1227 cp->p_fixalignment = pp->p_fixalignment;
1223 1228
1224 1229 *cpp = cp;
1225 1230 return (0);
1226 1231
1227 1232 bad:
1228 1233 ASSERT(MUTEX_NOT_HELD(&pidlock));
1229 1234
1230 1235 mutex_destroy(&cp->p_crlock);
1231 1236 mutex_destroy(&cp->p_pflock);
1232 1237 #if defined(__x86)
1233 1238 mutex_destroy(&cp->p_ldtlock);
1234 1239 #endif
1235 1240 if (newpid != -1) {
1236 1241 proc_entry_free(cp->p_pidp);
1237 1242 (void) pid_rele(cp->p_pidp);
1238 1243 }
1239 1244 kmem_cache_free(process_cache, cp);
1240 1245
1241 1246 mutex_enter(&zone->zone_nlwps_lock);
1242 1247 task->tk_nprocs--;
1243 1248 proj->kpj_nprocs--;
1244 1249 zone->zone_nprocs--;
1245 1250 mutex_exit(&zone->zone_nlwps_lock);
1246 1251 atomic_inc_32(&zone->zone_ffnoproc);
1247 1252
1248 1253 punish:
1249 1254 /*
1250 1255 * We most likely got into this situation because some process is
1251 1256 * forking out of control. As punishment, put it to sleep for a
1252 1257 * bit so it can't eat the machine alive. Sleep interval is chosen
1253 1258 * to allow no more than one fork failure per cpu per clock tick
1254 1259 * on average (yes, I just made this up). This has two desirable
1255 1260 * properties: (1) it sets a constant limit on the fork failure
1256 1261 * rate, and (2) the busier the system is, the harsher the penalty
1257 1262 * for abusing it becomes.
1258 1263 */
1259 1264 INCR_COUNT(&fork_fail_pending, &pidlock);
1260 1265 delay(fork_fail_pending / ncpus + 1);
1261 1266 DECR_COUNT(&fork_fail_pending, &pidlock);
1262 1267
1263 1268 return (-1); /* out of memory or proc slots */
1264 1269 }
1265 1270
1266 1271 /*
1267 1272 * Release virtual memory.
1268 1273 * In the case of vfork(), the child was given exclusive access to its
1269 1274 * parent's address space. The parent is waiting in vfwait() for the
1270 1275 * child to release its exclusive claim via relvm().
1271 1276 */
1272 1277 void
1273 1278 relvm()
1274 1279 {
1275 1280 proc_t *p = curproc;
1276 1281
1277 1282 ASSERT((unsigned)p->p_lwpcnt <= 1);
1278 1283
1279 1284 prrelvm(); /* inform /proc */
1280 1285
1281 1286 if (p->p_flag & SVFORK) {
1282 1287 proc_t *pp = p->p_parent;
1283 1288 /*
1284 1289 * The child process is either exec'ing or exit'ing.
1285 1290 * The child is now separated from the parent's address
1286 1291 * space. The parent process is made dispatchable.
1287 1292 *
1288 1293 * This is a delicate locking maneuver, involving
1289 1294 * both the parent's p_lock and the child's p_lock.
1290 1295 * As soon as the SVFORK flag is turned off, the
1291 1296 * parent is free to run, but it must not run until
1292 1297 * we wake it up using its p_cv because it might
1293 1298 * exit and we would be referencing invalid memory.
1294 1299 * Therefore, we hold the parent with its p_lock
1295 1300 * while protecting our p_flags with our own p_lock.
1296 1301 */
1297 1302 try_again:
1298 1303 mutex_enter(&p->p_lock); /* grab child's lock first */
1299 1304 prbarrier(p); /* make sure /proc is blocked out */
1300 1305 mutex_enter(&pp->p_lock);
1301 1306
1302 1307 /*
1303 1308 * Check if parent is locked by /proc.
1304 1309 */
1305 1310 if (pp->p_proc_flag & P_PR_LOCK) {
1306 1311 /*
1307 1312 * Delay until /proc is done with the parent.
1308 1313 * We must drop our (the child's) p->p_lock, wait
1309 1314 * via prbarrier() on the parent, then start over.
1310 1315 */
1311 1316 mutex_exit(&p->p_lock);
1312 1317 prbarrier(pp);
1313 1318 mutex_exit(&pp->p_lock);
1314 1319 goto try_again;
1315 1320 }
1316 1321 p->p_flag &= ~SVFORK;
1317 1322 kpreempt_disable();
1318 1323 p->p_as = &kas;
1319 1324
1320 1325 /*
1321 1326 * notify hat of change in thread's address space
1322 1327 */
1323 1328 hat_thread_exit(curthread);
1324 1329 kpreempt_enable();
1325 1330
1326 1331 /*
1327 1332 * child sizes are copied back to parent because
1328 1333 * child may have grown.
1329 1334 */
1330 1335 pp->p_brkbase = p->p_brkbase;
1331 1336 pp->p_brksize = p->p_brksize;
1332 1337 pp->p_stksize = p->p_stksize;
1333 1338
1334 1339 /*
1335 1340 * Copy back the shm accounting information
1336 1341 * to the parent process.
1337 1342 */
1338 1343 pp->p_segacct = p->p_segacct;
1339 1344 p->p_segacct = NULL;
1340 1345
1341 1346 /*
1342 1347 * The parent is no longer waiting for the vfork()d child.
1343 1348 * Restore the parent's watched pages, if any. This is
1344 1349 * safe because we know the parent is not locked by /proc
1345 1350 */
1346 1351 pp->p_flag &= ~SVFWAIT;
1347 1352 if (avl_numnodes(&pp->p_wpage) != 0) {
1348 1353 pp->p_as->a_wpage = pp->p_wpage;
1349 1354 avl_create(&pp->p_wpage, wp_compare,
1350 1355 sizeof (struct watched_page),
1351 1356 offsetof(struct watched_page, wp_link));
1352 1357 }
1353 1358 cv_signal(&pp->p_cv);
1354 1359 mutex_exit(&pp->p_lock);
1355 1360 mutex_exit(&p->p_lock);
1356 1361 } else {
1357 1362 if (p->p_as != &kas) {
1358 1363 struct as *as;
1359 1364
1360 1365 if (p->p_segacct)
1361 1366 shmexit(p);
1362 1367
1363 1368 /*
1364 1369 * We grab p_lock for the benefit of /proc
1365 1370 */
1366 1371 kpreempt_disable();
1367 1372 mutex_enter(&p->p_lock);
1368 1373 prbarrier(p); /* make sure /proc is blocked out */
1369 1374 as = p->p_as;
1370 1375 p->p_as = &kas;
1371 1376 mutex_exit(&p->p_lock);
1372 1377
1373 1378 /*
1374 1379 * notify hat of change in thread's address space
1375 1380 */
1376 1381 hat_thread_exit(curthread);
1377 1382 kpreempt_enable();
1378 1383
1379 1384 as_free(as);
1380 1385 p->p_tr_lgrpid = LGRP_NONE;
1381 1386 }
1382 1387 }
1383 1388 }
1384 1389
1385 1390 /*
1386 1391 * Wait for child to exec or exit.
1387 1392 * Called by parent of vfork'ed process.
1388 1393 * See important comments in relvm(), above.
1389 1394 */
1390 1395 void
1391 1396 vfwait(pid_t pid)
1392 1397 {
1393 1398 int signalled = 0;
1394 1399 proc_t *pp = ttoproc(curthread);
1395 1400 proc_t *cp;
1396 1401
1397 1402 /*
1398 1403 * Wait for child to exec or exit.
1399 1404 */
1400 1405 for (;;) {
1401 1406 mutex_enter(&pidlock);
1402 1407 cp = prfind(pid);
1403 1408 if (cp == NULL || cp->p_parent != pp) {
1404 1409 /*
1405 1410 * Child has exit()ed.
1406 1411 */
1407 1412 mutex_exit(&pidlock);
1408 1413 break;
1409 1414 }
1410 1415 /*
1411 1416 * Grab the child's p_lock before releasing pidlock.
1412 1417 * Otherwise, the child could exit and we would be
1413 1418 * referencing invalid memory.
1414 1419 */
1415 1420 mutex_enter(&cp->p_lock);
1416 1421 mutex_exit(&pidlock);
1417 1422 if (!(cp->p_flag & SVFORK)) {
1418 1423 /*
1419 1424 * Child has exec()ed or is exit()ing.
1420 1425 */
1421 1426 mutex_exit(&cp->p_lock);
1422 1427 break;
1423 1428 }
1424 1429 mutex_enter(&pp->p_lock);
1425 1430 mutex_exit(&cp->p_lock);
1426 1431 /*
1427 1432 * We might be waked up spuriously from the cv_wait().
1428 1433 * We have to do the whole operation over again to be
1429 1434 * sure the child's SVFORK flag really is turned off.
1430 1435 * We cannot make reference to the child because it can
1431 1436 * exit before we return and we would be referencing
1432 1437 * invalid memory.
1433 1438 *
1434 1439 * Because this is potentially a very long-term wait,
1435 1440 * we call cv_wait_sig() (for its jobcontrol and /proc
1436 1441 * side-effects) unless there is a current signal, in
1437 1442 * which case we use cv_wait() because we cannot return
1438 1443 * from this function until the child has released the
1439 1444 * address space. Calling cv_wait_sig() with a current
1440 1445 * signal would lead to an indefinite loop here because
1441 1446 * cv_wait_sig() returns immediately in this case.
1442 1447 */
1443 1448 if (signalled)
1444 1449 cv_wait(&pp->p_cv, &pp->p_lock);
1445 1450 else
1446 1451 signalled = !cv_wait_sig(&pp->p_cv, &pp->p_lock);
1447 1452 mutex_exit(&pp->p_lock);
1448 1453 }
1449 1454
1450 1455 /* restore watchpoints to parent */
1451 1456 if (pr_watch_active(pp)) {
1452 1457 struct as *as = pp->p_as;
1453 1458 AS_LOCK_ENTER(as, RW_WRITER);
1454 1459 as_setwatch(as);
1455 1460 AS_LOCK_EXIT(as);
1456 1461 }
1457 1462
1458 1463 mutex_enter(&pp->p_lock);
1459 1464 prbarrier(pp); /* barrier against /proc locking */
1460 1465 continuelwps(pp);
1461 1466 mutex_exit(&pp->p_lock);
1462 1467 }
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