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 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(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 if ((i = resolvepath(buf, buf, PATH_MAX)) > 0) { 64 buf[i] = '\0'; 65 return (isexec(buf, isdata)); 66 } 67 68 return (0); /* resolvepath failed */ 69 } 70 71 /* 72 * The Pfindexec function contains the logic for the executable name dance. 73 * The caller provides a possible executable name or likely directory (the 74 * aout parameter), and a function which is responsible for doing any 75 * final confirmation on the executable pathname once a possible full 76 * pathname has been chosen. 77 */ 78 char * 79 Pfindexec(struct ps_prochandle *P, const char *aout, 80 int (*isexec)(const char *, void *), void *isdata) 81 { 82 char cwd[PATH_MAX * 2]; 83 char path[PATH_MAX]; 84 char buf[PATH_MAX]; 85 struct stat st; 86 uintptr_t addr; 87 char *p, *q; 88 89 if (P->execname) 90 return (P->execname); /* Already found */ 91 92 errno = 0; /* Set to zero so we can tell if stat() failed */ 93 94 /* 95 * First try: use the provided default value, if it is not a directory. 96 * If the aout parameter turns out to be a directory, this is 97 * interpreted as the directory to use as an alternate cwd for 98 * our subsequent attempts to locate the executable. 99 */ 100 if (aout != NULL && stat(aout, &st) == 0 && !S_ISDIR(st.st_mode)) { 101 if (try_exec(".", aout, buf, isexec, isdata)) 102 goto found; 103 else 104 aout = "."; 105 106 } else if (aout == NULL || errno != 0) 107 aout = "."; 108 109 /* 110 * At this point 'aout' is either "." or an alternate cwd. We use 111 * realpath(3c) to turn this into a full pathname free of ".", "..", 112 * and symlinks. If this fails for some reason, fall back to "." 113 */ 114 if (realpath(aout, cwd) == NULL) 115 (void) strcpy(cwd, "."); 116 117 /* 118 * Second try: read the string pointed to by the AT_SUN_EXECNAME 119 * auxv element, saved when the program was exec'd. If the full 120 * pathname try_exec() forms fails, try again using just the 121 * basename appended to our cwd. 122 */ 123 if ((addr = Pgetauxval(P, AT_SUN_EXECNAME)) != (uintptr_t)-1L && 124 Pread_string(P, path, sizeof (path), (off_t)addr) > 0) { 125 126 if (try_exec(cwd, path, buf, isexec, isdata)) 127 goto found; 128 129 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 130 try_exec(cwd, p, buf, isexec, isdata)) 131 goto found; 132 } 133 134 /* 135 * Third try: try using the first whitespace-separated token 136 * saved in the psinfo_t's pr_psargs (the initial value of argv[0]). 137 */ 138 if (Ppsinfo(P) != NULL) { 139 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ); 140 path[PRARGSZ] = '\0'; 141 142 if ((p = strchr(path, ' ')) != NULL) 143 *p = '\0'; 144 145 if (try_exec(cwd, path, buf, isexec, isdata)) 146 goto found; 147 148 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 149 try_exec(cwd, p, buf, isexec, isdata)) 150 goto found; 151 } 152 153 /* 154 * Fourth try: read the string pointed to by argv[0] out of the 155 * stack in the process's address space. 156 */ 157 if (P->psinfo.pr_argv != NULL && 158 Pread(P, &addr, sizeof (addr), P->psinfo.pr_argv) != -1 && 159 Pread_string(P, path, sizeof (path), (off_t)addr) > 0) { 160 161 if (try_exec(cwd, path, buf, isexec, isdata)) 162 goto found; 163 164 if (strchr(path, '/') != NULL && (p = basename(path)) != NULL && 165 try_exec(cwd, p, buf, isexec, isdata)) 166 goto found; 167 } 168 169 /* 170 * Fifth try: read the process's $PATH environment variable and 171 * search each directory named there for the name matching pr_fname. 172 */ 173 if (Pgetenv(P, "PATH", cwd, sizeof (cwd)) != NULL) { 174 /* 175 * If the name from pr_psargs contains pr_fname as its 176 * leading string, then accept the name from pr_psargs 177 * because more bytes are saved there. Otherwise use 178 * pr_fname because this gives us new information. 179 */ 180 (void) strncpy(path, P->psinfo.pr_psargs, PRARGSZ); 181 path[PRARGSZ] = '\0'; 182 183 if ((p = strchr(path, ' ')) != NULL) 184 *p = '\0'; 185 186 if (strchr(path, '/') != NULL || strncmp(path, 187 P->psinfo.pr_fname, strlen(P->psinfo.pr_fname)) != 0) 188 (void) strcpy(path, P->psinfo.pr_fname); 189 190 /* 191 * Now iterate over the $PATH elements, trying to form 192 * an executable pathname with each one. 193 */ 194 for (p = strtok_r(cwd, ":", &q); p != NULL; 195 p = strtok_r(NULL, ":", &q)) { 196 197 if (*p != '/') 198 continue; /* Ignore anything relative */ 199 200 if (try_exec(p, path, buf, isexec, isdata)) 201 goto found; 202 } 203 } 204 205 errno = ENOENT; 206 return (NULL); 207 208 found: 209 if ((P->execname = strdup(buf)) == NULL) 210 dprintf("failed to malloc; executable name is \"%s\"", buf); 211 212 return (P->execname); 213 } 214 215 /* 216 * Callback function for Pfindexec(). We return a match if we can stat the 217 * suggested pathname and confirm its device and inode number match our 218 * previous information about the /proc/<pid>/object/a.out file. 219 */ 220 static int 221 stat_exec(const char *path, struct stat64 *stp) 222 { 223 struct stat64 st; 224 225 return (stat64(path, &st) == 0 && S_ISREG(st.st_mode) && 226 stp->st_dev == st.st_dev && stp->st_ino == st.st_ino); 227 } 228 229 /* 230 * Return the full pathname for the executable file. If the process handle is 231 * a core file, we've already tried our best to get the executable name. 232 * Otherwise, we make an attempt using Pfindexec(). 233 */ 234 char * 235 Pexecname(struct ps_prochandle *P, char *buf, size_t buflen) 236 { 237 if (P->execname == NULL && P->state != PS_DEAD && P->state != PS_IDLE) { 238 char exec_name[PATH_MAX]; 239 char cwd[PATH_MAX]; 240 char proc_cwd[64]; 241 struct stat64 st; 242 int ret; 243 244 /* 245 * Try to get the path information first. 246 */ 247 (void) snprintf(exec_name, sizeof (exec_name), 248 "/proc/%d/path/a.out", (int)P->pid); 249 if ((ret = readlink(exec_name, buf, buflen - 1)) > 0) { 250 buf[ret] = '\0'; 251 return (buf); 252 } 253 254 /* 255 * Stat the executable file so we can compare Pfindexec's 256 * suggestions to the actual device and inode number. 257 */ 258 (void) snprintf(exec_name, sizeof (exec_name), 259 "/proc/%d/object/a.out", (int)P->pid); 260 261 if (stat64(exec_name, &st) != 0 || !S_ISREG(st.st_mode)) 262 return (NULL); 263 264 /* 265 * Attempt to figure out the current working directory of the 266 * target process. This only works if the target process has 267 * not changed its current directory since it was exec'd. 268 */ 269 (void) snprintf(proc_cwd, sizeof (proc_cwd), 270 "/proc/%d/path/cwd", (int)P->pid); 271 272 if ((ret = readlink(proc_cwd, cwd, PATH_MAX - 1)) > 0) 273 cwd[ret] = '\0'; 274 275 (void) Pfindexec(P, ret > 0 ? cwd : NULL, 276 (int (*)(const char *, void *))stat_exec, &st); 277 } 278 279 if (P->execname != NULL) { 280 (void) strncpy(buf, P->execname, buflen); 281 return (buf); 282 } 283 284 return (NULL); 285 } 286