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 <libzonecfg.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 zname[ZONENAME_MAX]; 128 char zpath[PATH_MAX]; 129 const psinfo_t *pi = Ppsinfo(P); 130 131 if (try_exec(cwd, path, buf, isexec, isdata)) 132 goto found; 133 134 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 135 try_exec(cwd, p, buf, isexec, isdata)) 136 goto found; 137 138 if (getzonenamebyid(pi->pr_zoneid, zname, 139 sizeof (zname)) != -1 && strcmp(zname, "global") != 0 && 140 zone_get_zonepath(zname, zpath, sizeof (zpath)) == Z_OK) { 141 (void) strcat(zpath, "/root"); 142 if (try_exec(zpath, p, buf, isexec, isdata)) 143 goto found; 144 } 145 } 146 147 /* 148 * Third try: try using the first whitespace-separated token 149 * saved in the psinfo_t's pr_psargs (the initial value of argv[0]). 150 */ 151 if (Ppsinfo(P) != NULL) { 152 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ); 153 path[PRARGSZ] = '\0'; 154 155 if ((p = strchr(path, ' ')) != NULL) 156 *p = '\0'; 157 158 if (try_exec(cwd, path, buf, isexec, isdata)) 159 goto found; 160 161 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 162 try_exec(cwd, p, buf, isexec, isdata)) 163 goto found; 164 } 165 166 /* 167 * Fourth try: read the string pointed to by argv[0] out of the 168 * stack in the process's address space. 169 */ 170 if (P->psinfo.pr_argv != NULL && 171 Pread(P, &addr, sizeof (addr), P->psinfo.pr_argv) != -1 && 172 Pread_string(P, path, sizeof (path), (off_t)addr) > 0) { 173 174 if (try_exec(cwd, path, buf, isexec, isdata)) 175 goto found; 176 177 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 178 try_exec(cwd, p, buf, isexec, isdata)) 179 goto found; 180 } 181 182 /* 183 * Fifth try: read the process's $PATH environment variable and 184 * search each directory named there for the name matching pr_fname. 185 */ 186 if (Pgetenv(P, "PATH", cwd, sizeof (cwd)) != NULL) { 187 /* 188 * If the name from pr_psargs contains pr_fname as its 189 * leading string, then accept the name from pr_psargs 190 * because more bytes are saved there. Otherwise use 191 * pr_fname because this gives us new information. 192 */ 193 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ); 194 path[PRARGSZ] = '\0'; 195 196 if ((p = strchr(path, ' ')) != NULL) 197 *p = '\0'; 198 199 if (strchr(path, '/') != NULL || strncmp(path, 200 P->psinfo.pr_fname, strlen(P->psinfo.pr_fname)) != 0) 201 (void) strcpy(path, P->psinfo.pr_fname); 202 203 /* 204 * Now iterate over the $PATH elements, trying to form 205 * an executable pathname with each one. 206 */ 207 for (p = strtok_r(cwd, ":", &q); p != NULL; 208 p = strtok_r(NULL, ":", &q)) { 209 210 if (*p != '/') 211 continue; /* Ignore anything relative */ 212 213 if (try_exec(p, path, buf, isexec, isdata)) 214 goto found; 215 } 216 } 217 218 errno = ENOENT; 219 return (NULL); 220 221 found: 222 if ((P->execname = strdup(buf)) == NULL) 223 dprintf("failed to malloc; executable name is \"%s\"", buf); 224 225 return (P->execname); 226 } 227 228 /* 229 * Callback function for Pfindexec(). We return a match if we can stat the 230 * suggested pathname and confirm its device and inode number match our 231 * previous information about the /proc/<pid>/object/a.out file. 232 */ 233 static int 234 stat_exec(const char *path, struct stat64 *stp) 235 { 236 struct stat64 st; 237 238 return (stat64(path, &st) == 0 && S_ISREG(st.st_mode) && 239 stp->st_dev == st.st_dev && stp->st_ino == st.st_ino); 240 } 241 242 /* 243 * Return the full pathname for the executable file. If the process handle is 244 * a core file, we've already tried our best to get the executable name. 245 * Otherwise, we make an attempt using Pfindexec(). 246 */ 247 char * 248 Pexecname(struct ps_prochandle *P, char *buf, size_t buflen) 249 { 250 if (P->execname == NULL && P->state != PS_DEAD && P->state != PS_IDLE) { 251 char exec_name[PATH_MAX]; 252 char cwd[PATH_MAX]; 253 char proc_cwd[64]; 254 struct stat64 st; 255 int ret; 256 257 /* 258 * Try to get the path information first. 259 */ 260 (void) snprintf(exec_name, sizeof (exec_name), 261 "%s/%d/path/a.out", procfs_path, (int)P->pid); 262 if ((ret = readlink(exec_name, buf, buflen - 1)) > 0) { 263 buf[ret] = '\0'; 264 return (buf); 265 } 266 267 /* 268 * Stat the executable file so we can compare Pfindexec's 269 * suggestions to the actual device and inode number. 270 */ 271 (void) snprintf(exec_name, sizeof (exec_name), 272 "%s/%d/object/a.out", procfs_path, (int)P->pid); 273 274 if (stat64(exec_name, &st) != 0 || !S_ISREG(st.st_mode)) 275 return (NULL); 276 277 /* 278 * Attempt to figure out the current working directory of the 279 * target process. This only works if the target process has 280 * not changed its current directory since it was exec'd. 281 */ 282 (void) snprintf(proc_cwd, sizeof (proc_cwd), 283 "%s/%d/path/cwd", procfs_path, (int)P->pid); 284 285 if ((ret = readlink(proc_cwd, cwd, PATH_MAX - 1)) > 0) 286 cwd[ret] = '\0'; 287 288 (void) Pfindexec(P, ret > 0 ? cwd : NULL, 289 (int (*)(const char *, void *))stat_exec, &st); 290 } 291 292 if (P->execname != NULL) { 293 (void) strncpy(buf, P->execname, buflen); 294 return (buf); 295 } 296 297 return (NULL); 298 } 299