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 2006 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 #define __EXTENSIONS__ 29 #include <string.h> 30 #undef __EXTENSIONS__ 31 32 #include <libgen.h> 33 #include <limits.h> 34 #include <stdio.h> 35 #include <errno.h> 36 #include <unistd.h> 37 #include <zone.h> 38 39 #include "Pcontrol.h" 40 41 /* 42 * Pexecname.c - Way too much code to attempt to derive the full pathname of 43 * the executable file from a process handle, be it dead or alive. 44 */ 45 46 /* 47 * Once we've computed a cwd and a relative path, we use try_exec() to 48 * form an absolute path, call resolvepath() on it, and then let the 49 * caller's function do the final confirmation. 50 */ 51 static int 52 try_exec(const char *cwd, const char *path, char *buf, 53 int (*isexec)(const char *, void *), void *isdata) 54 { 55 int i; 56 57 if (path[0] != '/') 58 (void) snprintf(buf, PATH_MAX, "%s/%s", cwd, path); 59 else 60 (void) strcpy(buf, path); 61 62 dprintf("try_exec \"%s\"\n", buf); 63 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 if (P->execname) 91 return (P->execname); /* Already found */ 92 93 errno = 0; /* Set to zero so we can tell if stat() failed */ 94 95 /* 96 * First try: use the provided default value, if it is not a directory. 97 * If the aout parameter turns out to be a directory, this is 98 * interpreted as the directory to use as an alternate cwd for 99 * our subsequent attempts to locate the executable. 100 */ 101 if (aout != NULL && stat(aout, &st) == 0 && !S_ISDIR(st.st_mode)) { 102 if (try_exec(".", aout, buf, isexec, isdata)) 103 goto found; 104 else 105 aout = "."; 106 107 } else if (aout == NULL || errno != 0) 108 aout = "."; 109 110 /* 111 * At this point 'aout' is either "." or an alternate cwd. We use 112 * realpath(3c) to turn this into a full pathname free of ".", "..", 113 * and symlinks. If this fails for some reason, fall back to "." 114 */ 115 if (realpath(aout, cwd) == NULL) 116 (void) strcpy(cwd, "."); 117 118 /* 119 * Second try: read the string pointed to by the AT_SUN_EXECNAME 120 * auxv element, saved when the program was exec'd. If the full 121 * pathname try_exec() forms fails, try again using just the 122 * basename appended to our cwd. If that also fails, and the process 123 * is in a zone, try again with the zone path instead of our cwd. 124 */ 125 if ((addr = Pgetauxval(P, AT_SUN_EXECNAME)) != (uintptr_t)-1L && 126 Pread_string(P, path, sizeof (path), (off_t)addr) > 0) { 127 char zpath[PATH_MAX]; 128 const psinfo_t *pi = Ppsinfo(P); 129 130 if (try_exec(cwd, path, buf, isexec, isdata)) 131 goto found; 132 133 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 134 try_exec(cwd, p, buf, isexec, isdata)) 135 goto found; 136 137 if (getzoneid() == GLOBAL_ZONEID && 138 pi->pr_zoneid != GLOBAL_ZONEID && 139 zone_getattr(pi->pr_zoneid, ZONE_ATTR_ROOT, zpath, 140 sizeof (zpath)) != -1) { 141 /* 142 * try_exec() only combines its cwd and path arguments 143 * if path is relative; but in our case even an absolute 144 * path inside a zone is a relative path from the global 145 * zone perspective. So we turn a non-global zone's 146 * absolute path into a relative path here before 147 * calling try_exec(). 148 */ 149 p = (path[0] == '/') ? path + 1 : path; 150 if (try_exec(zpath, p, buf, isexec, isdata)) 151 goto found; 152 } 153 } 154 155 /* 156 * Third try: try using the first whitespace-separated token 157 * saved in the psinfo_t's pr_psargs (the initial value of argv[0]). 158 */ 159 if (Ppsinfo(P) != NULL) { 160 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ); 161 path[PRARGSZ] = '\0'; 162 163 if ((p = strchr(path, ' ')) != NULL) 164 *p = '\0'; 165 166 if (try_exec(cwd, path, buf, isexec, isdata)) 167 goto found; 168 169 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 170 try_exec(cwd, p, buf, isexec, isdata)) 171 goto found; 172 } 173 174 /* 175 * Fourth try: read the string pointed to by argv[0] out of the 176 * stack in the process's address space. 177 */ 178 if (P->psinfo.pr_argv != NULL && 179 Pread(P, &addr, sizeof (addr), P->psinfo.pr_argv) != -1 && 180 Pread_string(P, path, sizeof (path), (off_t)addr) > 0) { 181 182 if (try_exec(cwd, path, buf, isexec, isdata)) 183 goto found; 184 185 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 186 try_exec(cwd, p, buf, isexec, isdata)) 187 goto found; 188 } 189 190 /* 191 * Fifth try: read the process's $PATH environment variable and 192 * search each directory named there for the name matching pr_fname. 193 */ 194 if (Pgetenv(P, "PATH", cwd, sizeof (cwd)) != NULL) { 195 /* 196 * If the name from pr_psargs contains pr_fname as its 197 * leading string, then accept the name from pr_psargs 198 * because more bytes are saved there. Otherwise use 199 * pr_fname because this gives us new information. 200 */ 201 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ); 202 path[PRARGSZ] = '\0'; 203 204 if ((p = strchr(path, ' ')) != NULL) 205 *p = '\0'; 206 207 if (strchr(path, '/') != NULL || strncmp(path, 208 P->psinfo.pr_fname, strlen(P->psinfo.pr_fname)) != 0) 209 (void) strcpy(path, P->psinfo.pr_fname); 210 211 /* 212 * Now iterate over the $PATH elements, trying to form 213 * an executable pathname with each one. 214 */ 215 for (p = strtok_r(cwd, ":", &q); p != NULL; 216 p = strtok_r(NULL, ":", &q)) { 217 218 if (*p != '/') 219 continue; /* Ignore anything relative */ 220 221 if (try_exec(p, path, buf, isexec, isdata)) 222 goto found; 223 } 224 } 225 226 errno = ENOENT; 227 return (NULL); 228 229 found: 230 if ((P->execname = strdup(buf)) == NULL) 231 dprintf("failed to malloc; executable name is \"%s\"", buf); 232 233 return (P->execname); 234 } 235 236 /* 237 * Callback function for Pfindexec(). We return a match if we can stat the 238 * suggested pathname and confirm its device and inode number match our 239 * previous information about the /proc/<pid>/object/a.out file. 240 */ 241 static int 242 stat_exec(const char *path, struct stat64 *stp) 243 { 244 struct stat64 st; 245 246 return (stat64(path, &st) == 0 && S_ISREG(st.st_mode) && 247 stp->st_dev == st.st_dev && stp->st_ino == st.st_ino); 248 } 249 250 /* 251 * Return the full pathname for the executable file. If the process handle is 252 * a core file, we've already tried our best to get the executable name. 253 * Otherwise, we make an attempt using Pfindexec(). 254 */ 255 char * 256 Pexecname(struct ps_prochandle *P, char *buf, size_t buflen) 257 { 258 if (P->execname == NULL && P->state != PS_DEAD && P->state != PS_IDLE) { 259 char exec_name[PATH_MAX]; 260 char cwd[PATH_MAX]; 261 char proc_cwd[64]; 262 struct stat64 st; 263 int ret; 264 265 /* 266 * Try to get the path information first. 267 */ 268 (void) snprintf(exec_name, sizeof (exec_name), 269 "%s/%d/path/a.out", procfs_path, (int)P->pid); 270 if ((ret = readlink(exec_name, buf, buflen - 1)) > 0) { 271 buf[ret] = '\0'; 272 return (buf); 273 } 274 275 /* 276 * Stat the executable file so we can compare Pfindexec's 277 * suggestions to the actual device and inode number. 278 */ 279 (void) snprintf(exec_name, sizeof (exec_name), 280 "%s/%d/object/a.out", procfs_path, (int)P->pid); 281 282 if (stat64(exec_name, &st) != 0 || !S_ISREG(st.st_mode)) 283 return (NULL); 284 285 /* 286 * Attempt to figure out the current working directory of the 287 * target process. This only works if the target process has 288 * not changed its current directory since it was exec'd. 289 */ 290 (void) snprintf(proc_cwd, sizeof (proc_cwd), 291 "%s/%d/path/cwd", procfs_path, (int)P->pid); 292 293 if ((ret = readlink(proc_cwd, cwd, PATH_MAX - 1)) > 0) 294 cwd[ret] = '\0'; 295 296 (void) Pfindexec(P, ret > 0 ? cwd : NULL, 297 (int (*)(const char *, void *))stat_exec, &st); 298 } 299 300 if (P->execname != NULL) { 301 (void) strncpy(buf, P->execname, buflen); 302 return (buf); 303 } 304 305 return (NULL); 306 } 307