Bernhard Reutner-Fischer | 0a8812b | 2006-05-19 13:12:21 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Eric Andersen | 35e643b | 2003-07-28 07:40:39 +0000 | [diff] [blame] | 2 | /* |
Eric Andersen | aff114c | 2004-04-14 17:51:38 +0000 | [diff] [blame] | 3 | * Rexec program for system have fork() as vfork() with foreground option |
Russ Dill | a1fece2 | 2003-12-15 21:57:44 +0000 | [diff] [blame] | 4 | * |
| 5 | * Copyright (C) Vladimir N. Oleynik <dzo@simtreas.ru> |
| 6 | * Copyright (C) 2003 Russ Dill <Russ.Dill@asu.edu> |
| 7 | * |
Eric Andersen | aff114c | 2004-04-14 17:51:38 +0000 | [diff] [blame] | 8 | * daemon() portion taken from uClibc: |
Russ Dill | a1fece2 | 2003-12-15 21:57:44 +0000 | [diff] [blame] | 9 | * |
| 10 | * Copyright (c) 1991, 1993 |
| 11 | * The Regents of the University of California. All rights reserved. |
| 12 | * |
| 13 | * Modified for uClibc by Erik Andersen <andersee@debian.org> |
| 14 | * |
Bernhard Reutner-Fischer | 0a8812b | 2006-05-19 13:12:21 +0000 | [diff] [blame] | 15 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
Eric Andersen | 35e643b | 2003-07-28 07:40:39 +0000 | [diff] [blame] | 16 | */ |
| 17 | |
Russ Dill | a1fece2 | 2003-12-15 21:57:44 +0000 | [diff] [blame] | 18 | #include <paths.h> |
Denis Vlasenko | 335b63d | 2007-04-10 21:38:30 +0000 | [diff] [blame] | 19 | #include "busybox.h" /* for struct bb_applet */ |
Eric Andersen | 35e643b | 2003-07-28 07:40:39 +0000 | [diff] [blame] | 20 | |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 21 | /* This does a fork/exec in one call, using vfork(). Returns PID of new child, |
| 22 | * -1 for failure. Runs argv[0], searching path if that has no / in it. */ |
| 23 | pid_t spawn(char **argv) |
| 24 | { |
| 25 | /* Compiler should not optimize stores here */ |
| 26 | volatile int failed; |
| 27 | pid_t pid; |
| 28 | |
Denis Vlasenko | 7e754f1 | 2007-04-09 13:04:50 +0000 | [diff] [blame] | 29 | // Ain't it a good place to fflush(NULL)? |
| 30 | |
| 31 | /* Be nice to nommu machines. */ |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 32 | failed = 0; |
| 33 | pid = vfork(); |
| 34 | if (pid < 0) /* error */ |
| 35 | return pid; |
| 36 | if (!pid) { /* child */ |
Denis Vlasenko | 7e754f1 | 2007-04-09 13:04:50 +0000 | [diff] [blame] | 37 | /* This macro is ok - it doesn't do NOEXEC/NOFORK tricks */ |
| 38 | BB_EXECVP(argv[0], argv); |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 39 | |
| 40 | /* We are (maybe) sharing a stack with blocked parent, |
| 41 | * let parent know we failed and then exit to unblock parent |
| 42 | * (but don't run atexit() stuff, which would screw up parent.) |
| 43 | */ |
| 44 | failed = errno; |
Denis Vlasenko | afa7023 | 2007-03-26 17:25:33 +0000 | [diff] [blame] | 45 | _exit(111); |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 46 | } |
| 47 | /* parent */ |
Denis Vlasenko | afa7023 | 2007-03-26 17:25:33 +0000 | [diff] [blame] | 48 | /* Unfortunately, this is not reliable: according to standards |
| 49 | * vfork() can be equivalent to fork() and we won't see value |
| 50 | * of 'failed'. |
| 51 | * Interested party can wait on pid and learn exit code. |
| 52 | * If 111 - then it (most probably) failed to exec */ |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 53 | if (failed) { |
| 54 | errno = failed; |
| 55 | return -1; |
| 56 | } |
| 57 | return pid; |
| 58 | } |
| 59 | |
| 60 | /* Die with an error message if we can't spawn a child process. */ |
| 61 | pid_t xspawn(char **argv) |
| 62 | { |
| 63 | pid_t pid = spawn(argv); |
Denis Vlasenko | 53d445a | 2007-04-09 13:21:33 +0000 | [diff] [blame] | 64 | if (pid < 0) |
| 65 | bb_perror_msg_and_die("%s", *argv); |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 66 | return pid; |
| 67 | } |
| 68 | |
Denis Vlasenko | 53d445a | 2007-04-09 13:21:33 +0000 | [diff] [blame] | 69 | // Wait for the specified child PID to exit, returning child's error return. |
| 70 | int wait4pid(int pid) |
| 71 | { |
| 72 | int status; |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 73 | |
Denis Vlasenko | 53d445a | 2007-04-09 13:21:33 +0000 | [diff] [blame] | 74 | if (pid <= 0) { |
Denis Vlasenko | cd7001f | 2007-04-09 21:32:30 +0000 | [diff] [blame] | 75 | /*errno = ECHILD; -- wrong. */ |
| 76 | /* we expect errno to be already set from failed [v]fork/exec */ |
Denis Vlasenko | 53d445a | 2007-04-09 13:21:33 +0000 | [diff] [blame] | 77 | return -1; |
| 78 | } |
| 79 | if (waitpid(pid, &status, 0) == -1) |
| 80 | return -1; |
| 81 | if (WIFEXITED(status)) |
| 82 | return WEXITSTATUS(status); |
| 83 | if (WIFSIGNALED(status)) |
Denis Vlasenko | cd7001f | 2007-04-09 21:32:30 +0000 | [diff] [blame] | 84 | return WTERMSIG(status) + 1000; |
Denis Vlasenko | 53d445a | 2007-04-09 13:21:33 +0000 | [diff] [blame] | 85 | return 0; |
| 86 | } |
| 87 | |
| 88 | int wait_nohang(int *wstat) |
| 89 | { |
| 90 | return waitpid(-1, wstat, WNOHANG); |
| 91 | } |
| 92 | |
| 93 | int wait_pid(int *wstat, int pid) |
| 94 | { |
| 95 | int r; |
| 96 | |
| 97 | do |
| 98 | r = waitpid(pid, wstat, 0); |
| 99 | while ((r == -1) && (errno == EINTR)); |
| 100 | return r; |
| 101 | } |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 102 | |
Denis Vlasenko | 96f67dc | 2007-05-17 13:02:41 +0000 | [diff] [blame] | 103 | #if ENABLE_FEATURE_PREFER_APPLETS |
Denis Vlasenko | 18e19f2 | 2007-04-28 16:43:18 +0000 | [diff] [blame] | 104 | void save_nofork_data(struct nofork_save_area *save) |
| 105 | { |
Denis Vlasenko | b055001 | 2007-05-24 12:18:16 +0000 | [diff] [blame] | 106 | memcpy(&save->die_jmp, &die_jmp, sizeof(die_jmp)); |
Denis Vlasenko | 18e19f2 | 2007-04-28 16:43:18 +0000 | [diff] [blame] | 107 | save->current_applet = current_applet; |
| 108 | save->xfunc_error_retval = xfunc_error_retval; |
| 109 | save->option_mask32 = option_mask32; |
| 110 | save->die_sleep = die_sleep; |
| 111 | save->saved = 1; |
| 112 | } |
| 113 | |
| 114 | void restore_nofork_data(struct nofork_save_area *save) |
| 115 | { |
Denis Vlasenko | b055001 | 2007-05-24 12:18:16 +0000 | [diff] [blame] | 116 | memcpy(&die_jmp, &save->die_jmp, sizeof(die_jmp)); |
Denis Vlasenko | 18e19f2 | 2007-04-28 16:43:18 +0000 | [diff] [blame] | 117 | current_applet = save->current_applet; |
| 118 | xfunc_error_retval = save->xfunc_error_retval; |
| 119 | option_mask32 = save->option_mask32; |
| 120 | die_sleep = save->die_sleep; |
| 121 | |
| 122 | applet_name = current_applet->name; |
| 123 | } |
| 124 | |
| 125 | int run_nofork_applet_prime(struct nofork_save_area *old, const struct bb_applet *a, char **argv) |
Denis Vlasenko | f5294e1 | 2007-04-14 10:09:57 +0000 | [diff] [blame] | 126 | { |
| 127 | int rc, argc; |
| 128 | |
Denis Vlasenko | f5294e1 | 2007-04-14 10:09:57 +0000 | [diff] [blame] | 129 | current_applet = a; |
| 130 | applet_name = a->name; |
| 131 | xfunc_error_retval = EXIT_FAILURE; |
| 132 | /*option_mask32 = 0; - not needed */ |
| 133 | /* special flag for xfunc_die(). If xfunc will "die" |
| 134 | * in NOFORK applet, xfunc_die() sees negative |
| 135 | * die_sleep and longjmp here instead. */ |
| 136 | die_sleep = -1; |
| 137 | |
| 138 | argc = 1; |
| 139 | while (argv[argc]) |
| 140 | argc++; |
| 141 | |
| 142 | rc = setjmp(die_jmp); |
| 143 | if (!rc) { |
| 144 | /* Some callers (xargs) |
| 145 | * need argv untouched because they free argv[i]! */ |
| 146 | char *tmp_argv[argc+1]; |
| 147 | memcpy(tmp_argv, argv, (argc+1) * sizeof(tmp_argv[0])); |
| 148 | /* Finally we can call NOFORK applet's main() */ |
| 149 | rc = a->main(argc, tmp_argv); |
| 150 | } else { /* xfunc died in NOFORK applet */ |
| 151 | /* in case they meant to return 0... */ |
Denis Vlasenko | b055001 | 2007-05-24 12:18:16 +0000 | [diff] [blame] | 152 | if (rc == -2222) |
Denis Vlasenko | f5294e1 | 2007-04-14 10:09:57 +0000 | [diff] [blame] | 153 | rc = 0; |
| 154 | } |
| 155 | |
| 156 | /* Restoring globals */ |
Denis Vlasenko | 18e19f2 | 2007-04-28 16:43:18 +0000 | [diff] [blame] | 157 | restore_nofork_data(old); |
Denis Vlasenko | f5294e1 | 2007-04-14 10:09:57 +0000 | [diff] [blame] | 158 | return rc; |
| 159 | } |
| 160 | |
Denis Vlasenko | 18e19f2 | 2007-04-28 16:43:18 +0000 | [diff] [blame] | 161 | int run_nofork_applet(const struct bb_applet *a, char **argv) |
| 162 | { |
| 163 | struct nofork_save_area old; |
Denis Vlasenko | b055001 | 2007-05-24 12:18:16 +0000 | [diff] [blame] | 164 | |
Denis Vlasenko | 18e19f2 | 2007-04-28 16:43:18 +0000 | [diff] [blame] | 165 | /* Saving globals */ |
| 166 | save_nofork_data(&old); |
| 167 | return run_nofork_applet_prime(&old, a, argv); |
| 168 | } |
Denis Vlasenko | 96f67dc | 2007-05-17 13:02:41 +0000 | [diff] [blame] | 169 | #endif /* FEATURE_PREFER_APPLETS */ |
Denis Vlasenko | 18e19f2 | 2007-04-28 16:43:18 +0000 | [diff] [blame] | 170 | |
Denis Vlasenko | cd7001f | 2007-04-09 21:32:30 +0000 | [diff] [blame] | 171 | int spawn_and_wait(char **argv) |
| 172 | { |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 173 | int rc; |
Denis Vlasenko | d571c08 | 2007-04-11 07:26:56 +0000 | [diff] [blame] | 174 | #if ENABLE_FEATURE_PREFER_APPLETS |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 175 | const struct bb_applet *a = find_applet_by_name(argv[0]); |
Denis Vlasenko | 335b63d | 2007-04-10 21:38:30 +0000 | [diff] [blame] | 176 | |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 177 | if (a && (a->nofork |
Denis Vlasenko | 473dae0 | 2007-04-11 07:04:23 +0000 | [diff] [blame] | 178 | #if BB_MMU |
| 179 | || a->noexec /* NOEXEC trick needs fork() */ |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 180 | #endif |
| 181 | )) { |
Denis Vlasenko | 473dae0 | 2007-04-11 07:04:23 +0000 | [diff] [blame] | 182 | #if BB_MMU |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 183 | if (a->nofork) |
| 184 | #endif |
| 185 | { |
Denis Vlasenko | f5294e1 | 2007-04-14 10:09:57 +0000 | [diff] [blame] | 186 | return run_nofork_applet(a, argv); |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 187 | } |
Denis Vlasenko | 473dae0 | 2007-04-11 07:04:23 +0000 | [diff] [blame] | 188 | #if BB_MMU |
| 189 | /* MMU only */ |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 190 | /* a->noexec is true */ |
| 191 | rc = fork(); |
Denis Vlasenko | 473dae0 | 2007-04-11 07:04:23 +0000 | [diff] [blame] | 192 | if (rc) /* parent or error */ |
| 193 | return wait4pid(rc); |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 194 | /* child */ |
Denis Vlasenko | f1a7141 | 2007-04-10 23:32:37 +0000 | [diff] [blame] | 195 | xfunc_error_retval = EXIT_FAILURE; |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 196 | current_applet = a; |
Denis Vlasenko | f5294e1 | 2007-04-14 10:09:57 +0000 | [diff] [blame] | 197 | run_current_applet_and_exit(argv); |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 198 | #endif |
Denis Vlasenko | cd7001f | 2007-04-09 21:32:30 +0000 | [diff] [blame] | 199 | } |
Denis Vlasenko | 473dae0 | 2007-04-11 07:04:23 +0000 | [diff] [blame] | 200 | #endif /* FEATURE_PREFER_APPLETS */ |
Denis Vlasenko | cd7001f | 2007-04-09 21:32:30 +0000 | [diff] [blame] | 201 | rc = spawn(argv); |
Denis Vlasenko | cd7001f | 2007-04-09 21:32:30 +0000 | [diff] [blame] | 202 | return wait4pid(rc); |
Eric Andersen | 35e643b | 2003-07-28 07:40:39 +0000 | [diff] [blame] | 203 | } |
Denis Vlasenko | c6758a0 | 2007-04-10 21:40:19 +0000 | [diff] [blame] | 204 | |
Denis Vlasenko | 473dae0 | 2007-04-11 07:04:23 +0000 | [diff] [blame] | 205 | #if !BB_MMU |
Denis Vlasenko | 53091ec | 2007-03-26 13:35:09 +0000 | [diff] [blame] | 206 | void forkexit_or_rexec(char **argv) |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 207 | { |
| 208 | pid_t pid; |
| 209 | /* Maybe we are already re-execed and come here again? */ |
| 210 | if (re_execed) |
| 211 | return; |
| 212 | |
| 213 | pid = vfork(); |
| 214 | if (pid < 0) /* wtf? */ |
| 215 | bb_perror_msg_and_die("vfork"); |
| 216 | if (pid) /* parent */ |
| 217 | exit(0); |
| 218 | /* child - re-exec ourself */ |
| 219 | /* high-order bit of first char in argv[0] is a hidden |
| 220 | * "we have (alrealy) re-execed, don't do it again" flag */ |
| 221 | argv[0][0] |= 0x80; |
Denis Vlasenko | bdbbb7e | 2007-06-08 15:02:55 +0000 | [diff] [blame] | 222 | execv(bb_busybox_exec_path, argv); |
| 223 | bb_perror_msg_and_die("exec %s", bb_busybox_exec_path); |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 224 | } |
| 225 | #else |
Denis Vlasenko | 53091ec | 2007-03-26 13:35:09 +0000 | [diff] [blame] | 226 | /* Dance around (void)...*/ |
| 227 | #undef forkexit_or_rexec |
| 228 | void forkexit_or_rexec(void) |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 229 | { |
| 230 | pid_t pid; |
| 231 | pid = fork(); |
| 232 | if (pid < 0) /* wtf? */ |
| 233 | bb_perror_msg_and_die("fork"); |
| 234 | if (pid) /* parent */ |
| 235 | exit(0); |
| 236 | /* child */ |
| 237 | } |
Denis Vlasenko | 53091ec | 2007-03-26 13:35:09 +0000 | [diff] [blame] | 238 | #define forkexit_or_rexec(argv) forkexit_or_rexec() |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 239 | #endif |
| 240 | |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 241 | /* Due to a #define in libbb.h on MMU systems we actually have 1 argument - |
| 242 | * char **argv "vanishes" */ |
| 243 | void bb_daemonize_or_rexec(int flags, char **argv) |
| 244 | { |
| 245 | int fd; |
| 246 | |
| 247 | fd = xopen(bb_dev_null, O_RDWR); |
| 248 | |
| 249 | if (flags & DAEMON_CHDIR_ROOT) |
| 250 | xchdir("/"); |
| 251 | |
| 252 | if (flags & DAEMON_DEVNULL_STDIO) { |
| 253 | close(0); |
| 254 | close(1); |
| 255 | close(2); |
| 256 | } |
| 257 | |
| 258 | while ((unsigned)fd < 2) |
| 259 | fd = dup(fd); /* have 0,1,2 open at least to /dev/null */ |
| 260 | |
| 261 | if (!(flags & DAEMON_ONLY_SANITIZE)) { |
Denis Vlasenko | 53091ec | 2007-03-26 13:35:09 +0000 | [diff] [blame] | 262 | forkexit_or_rexec(argv); |
Denis Vlasenko | d8540f7 | 2007-06-14 07:53:06 +0000 | [diff] [blame] | 263 | /* if daemonizing, make sure we detach from stdio & ctty */ |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 264 | setsid(); |
| 265 | dup2(fd, 0); |
| 266 | dup2(fd, 1); |
| 267 | dup2(fd, 2); |
| 268 | } |
Denis Vlasenko | d8540f7 | 2007-06-14 07:53:06 +0000 | [diff] [blame] | 269 | while (fd > 2) { |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 270 | close(fd--); |
Denis Vlasenko | d8540f7 | 2007-06-14 07:53:06 +0000 | [diff] [blame] | 271 | if (!(flags & DAEMON_CLOSE_EXTRA_FDS)) |
| 272 | return; |
| 273 | /* else close everything after fd#2 */ |
| 274 | } |
Denis Vlasenko | bb7fcb4 | 2007-03-26 13:20:04 +0000 | [diff] [blame] | 275 | } |
| 276 | |
| 277 | void bb_sanitize_stdio(void) |
| 278 | { |
| 279 | bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE, NULL); |
| 280 | } |