1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #define __EXTENSIONS__
27 #include <string.h>
28 #undef __EXTENSIONS__
29
30 #include <libgen.h>
31 #include <limits.h>
32 #include <stdio.h>
33 #include <errno.h>
34 #include <unistd.h>
35 #include <zone.h>
36
37 #include "libproc.h"
38 #include "Pcontrol.h"
39
40 /*
41 * Pexecname.c - Way too much code to attempt to derive the full pathname of
42 * the executable file from a process handle, be it dead or alive.
43 */
44
45 /*
46 * Once we've computed a cwd and a relative path, we use try_exec() to
47 * form an absolute path, call resolvepath() on it, and then let the
48 * caller's function do the final confirmation.
49 */
50 static int
51 try_exec(struct ps_prochandle *P, const char *cwd, const char *path, char *buf,
52 int (*isexec)(const char *, void *), void *isdata)
53 {
54 int i;
55
56 if (path[0] != '/')
57 (void) snprintf(buf, PATH_MAX, "%s/%s", cwd, path);
58 else
59 (void) strcpy(buf, path);
60
61 dprintf("try_exec \"%s\"\n", buf);
62
63 (void) Pfindobj(P, buf, buf, PATH_MAX);
64 if ((i = resolvepath(buf, buf, PATH_MAX)) > 0) {
65 buf[i] = '\0';
66 return (isexec(buf, isdata));
67 }
68
69 return (0); /* resolvepath failed */
70 }
71
72 /*
73 * The Pfindexec function contains the logic for the executable name dance.
74 * The caller provides a possible executable name or likely directory (the
75 * aout parameter), and a function which is responsible for doing any
76 * final confirmation on the executable pathname once a possible full
77 * pathname has been chosen.
78 */
79 char *
80 Pfindexec(struct ps_prochandle *P, const char *aout,
81 int (*isexec)(const char *, void *), void *isdata)
82 {
83 char cwd[PATH_MAX * 2];
84 char path[PATH_MAX];
85 char buf[PATH_MAX];
86 struct stat st;
87 uintptr_t addr;
88 char *p = path, *q;
89
90 dprintf("Pfindexec '%s'\n", aout);
91
92 if (P->execname)
93 return (P->execname); /* Already found */
94
95 errno = 0; /* Set to zero so we can tell if stat() failed */
96
97 /*
98 * First try: use the provided default value, if it is not a directory.
99 * If the aout parameter turns out to be a directory, this is
100 * interpreted as the directory to use as an alternate cwd for
101 * our subsequent attempts to locate the executable.
102 */
103 if (aout != NULL && stat(aout, &st) == 0 && !S_ISDIR(st.st_mode)) {
104 if (try_exec(P, ".", aout, buf, isexec, isdata))
105 goto found;
106 else
107 aout = ".";
108
109 } else if (aout == NULL || errno != 0)
110 aout = ".";
111
112 /*
113 * At this point 'aout' is either "." or an alternate cwd. We use
114 * realpath(3c) to turn this into a full pathname free of ".", "..",
115 * and symlinks. If this fails for some reason, fall back to "."
116 */
117 if (realpath(aout, cwd) == NULL)
118 (void) strcpy(cwd, ".");
119
120 /*
121 * Second try: read the string pointed to by the AT_SUN_EXECNAME
122 * auxv element, saved when the program was exec'd. If the full
123 * pathname try_exec() forms fails, try again using just the
124 * basename appended to our cwd. If that also fails, and the process
125 * is in a zone, try again with the zone path instead of our cwd.
126 */
127 if ((addr = Pgetauxval(P, AT_SUN_EXECNAME)) != (uintptr_t)-1L &&
128 Pread_string(P, path, sizeof (path), (off_t)addr) > 0) {
129 char zpath[PATH_MAX];
130 const psinfo_t *pi = Ppsinfo(P);
131
132 if (try_exec(P, cwd, path, buf, isexec, isdata))
133 goto found;
134
135 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL &&
136 try_exec(P, cwd, p, buf, isexec, isdata))
137 goto found;
138
139 if (getzoneid() == GLOBAL_ZONEID &&
140 pi->pr_zoneid != GLOBAL_ZONEID &&
141 zone_getattr(pi->pr_zoneid, ZONE_ATTR_ROOT, zpath,
142 sizeof (zpath)) != -1) {
143 /*
144 * try_exec() only combines its cwd and path arguments
145 * if path is relative; but in our case even an absolute
146 * path inside a zone is a relative path from the global
147 * zone perspective. So we turn a non-global zone's
148 * absolute path into a relative path here before
149 * calling try_exec().
150 */
151 p = (path[0] == '/') ? path + 1 : path;
152 if (try_exec(P, zpath, p, buf, isexec, isdata))
153 goto found;
154 }
155 }
156
157 /*
158 * Third try: try using the first whitespace-separated token
159 * saved in the psinfo_t's pr_psargs (the initial value of argv[0]).
160 */
161 if (Ppsinfo(P) != NULL) {
162 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ);
163 path[PRARGSZ] = '\0';
164
165 if ((p = strchr(path, ' ')) != NULL)
166 *p = '\0';
167
168 if (try_exec(P, cwd, path, buf, isexec, isdata))
169 goto found;
170
171 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL &&
172 try_exec(P, cwd, p, buf, isexec, isdata))
173 goto found;
174 }
175
176 /*
177 * Fourth try: read the string pointed to by argv[0] out of the
178 * stack in the process's address space.
179 */
180 if (P->psinfo.pr_argv != NULL &&
181 Pread(P, &addr, sizeof (addr), P->psinfo.pr_argv) != -1 &&
182 Pread_string(P, path, sizeof (path), (off_t)addr) > 0) {
183
184 if (try_exec(P, cwd, path, buf, isexec, isdata))
185 goto found;
186
187 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL &&
188 try_exec(P, cwd, p, buf, isexec, isdata))
189 goto found;
190 }
191
192 /*
193 * Fifth try: read the process's $PATH environment variable and
194 * search each directory named there for the name matching pr_fname.
195 */
196 if (Pgetenv(P, "PATH", cwd, sizeof (cwd)) != NULL) {
197 /*
198 * If the name from pr_psargs contains pr_fname as its
199 * leading string, then accept the name from pr_psargs
200 * because more bytes are saved there. Otherwise use
201 * pr_fname because this gives us new information.
202 */
203 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ);
204 path[PRARGSZ] = '\0';
205
206 if ((p = strchr(path, ' ')) != NULL)
207 *p = '\0';
208
209 if (strchr(path, '/') != NULL || strncmp(path,
210 P->psinfo.pr_fname, strlen(P->psinfo.pr_fname)) != 0)
211 (void) strcpy(path, P->psinfo.pr_fname);
212
213 /*
214 * Now iterate over the $PATH elements, trying to form
215 * an executable pathname with each one.
216 */
217 for (p = strtok_r(cwd, ":", &q); p != NULL;
218 p = strtok_r(NULL, ":", &q)) {
219
220 if (*p != '/')
221 continue; /* Ignore anything relative */
222
223 if (try_exec(P, p, path, buf, isexec, isdata))
224 goto found;
225 }
226 }
227
228 errno = ENOENT;
229 return (NULL);
230
231 found:
232 if ((P->execname = strdup(buf)) == NULL)
233 dprintf("failed to malloc; executable name is \"%s\"", buf);
234
235 return (P->execname);
236 }
237
238 /*
239 * Callback function for Pfindexec(). We return a match if we can stat the
240 * suggested pathname and confirm its device and inode number match our
241 * previous information about the /proc/<pid>/object/a.out file.
242 */
243 static int
244 stat_exec(const char *path, struct stat64 *stp)
245 {
246 struct stat64 st;
247
248 return (stat64(path, &st) == 0 && S_ISREG(st.st_mode) &&
249 stp->st_dev == st.st_dev && stp->st_ino == st.st_ino);
250 }
251
252 /*
253 * Return the full pathname for the executable file. If the process handle is
254 * a core file, we've already tried our best to get the executable name.
255 * Otherwise, we make an attempt using Pfindexec().
256 */
257 char *
258 Pexecname(struct ps_prochandle *P, char *buf, size_t buflen)
259 {
260 if (P->execname != NULL) {
261 (void) strncpy(buf, P->execname, buflen);
262 return (buf);
263 }
264
265 if (P->state != PS_DEAD && P->state != PS_IDLE) {
266 char exec_name[PATH_MAX];
267 char cwd[PATH_MAX];
268 char proc_cwd[64];
269 struct stat64 st;
270 int ret;
271
272 /*
273 * Try to get the path information first.
274 */
275 (void) snprintf(exec_name, sizeof (exec_name),
276 "%s/%d/path/a.out", procfs_path, (int)P->pid);
277 if ((ret = readlink(exec_name, buf, buflen - 1)) > 0) {
278 buf[ret] = '\0';
279 (void) Pfindobj(P, buf, buf, buflen);
280 return (buf);
281 }
282
283 /*
284 * Stat the executable file so we can compare Pfindexec's
285 * suggestions to the actual device and inode number.
286 */
287 (void) snprintf(exec_name, sizeof (exec_name),
288 "%s/%d/object/a.out", procfs_path, (int)P->pid);
289
290 if (stat64(exec_name, &st) != 0 || !S_ISREG(st.st_mode))
291 return (NULL);
292
293 /*
294 * Attempt to figure out the current working directory of the
295 * target process. This only works if the target process has
296 * not changed its current directory since it was exec'd.
297 */
298 (void) snprintf(proc_cwd, sizeof (proc_cwd),
299 "%s/%d/path/cwd", procfs_path, (int)P->pid);
300
301 if ((ret = readlink(proc_cwd, cwd, PATH_MAX - 1)) > 0)
302 cwd[ret] = '\0';
303
304 (void) Pfindexec(P, ret > 0 ? cwd : NULL,
305 (int (*)(const char *, void *))stat_exec, &st);
306 }
307
308 return (NULL);
309 }