1 /* vi: set sw=4 ts=4: */
3 * Rexec program for system have fork() as vfork() with foreground option
5 * Copyright (C) Vladimir N. Oleynik <dzo@simtreas.ru>
6 * Copyright (C) 2003 Russ Dill <Russ.Dill@asu.edu>
8 * daemon() portion taken from uClibc:
10 * Copyright (c) 1991, 1993
11 * The Regents of the University of California. All rights reserved.
13 * Modified for uClibc by Erik Andersen <andersee@debian.org>
15 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
19 #include "busybox.h" /* for struct bb_applet */
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)
25 /* Compiler should not optimize stores here */
29 // Ain't it a good place to fflush(NULL)?
31 /* Be nice to nommu machines. */
34 if (pid < 0) /* error */
36 if (!pid) { /* child */
37 /* This macro is ok - it doesn't do NOEXEC/NOFORK tricks */
38 BB_EXECVP(argv[0], argv);
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.)
48 /* Unfortunately, this is not reliable: according to standards
49 * vfork() can be equivalent to fork() and we won't see value
51 * Interested party can wait on pid and learn exit code.
52 * If 111 - then it (most probably) failed to exec */
60 /* Die with an error message if we can't spawn a child process. */
61 pid_t xspawn(char **argv)
63 pid_t pid = spawn(argv);
65 bb_perror_msg_and_die("%s", *argv);
69 // Wait for the specified child PID to exit, returning child's error return.
75 /*errno = ECHILD; -- wrong. */
76 /* we expect errno to be already set from failed [v]fork/exec */
79 if (waitpid(pid, &status, 0) == -1)
81 if (WIFEXITED(status))
82 return WEXITSTATUS(status);
83 if (WIFSIGNALED(status))
84 return WTERMSIG(status) + 1000;
88 int wait_nohang(int *wstat)
90 return waitpid(-1, wstat, WNOHANG);
93 int wait_pid(int *wstat, int pid)
98 r = waitpid(pid, wstat, 0);
99 while ((r == -1) && (errno == EINTR));
103 int spawn_and_wait(char **argv)
107 #if ENABLE_FEATURE_EXEC_PREFER_APPLETS
109 const struct bb_applet *a = find_applet_by_name(argv[0]);
112 || a->noexec /* NOEXEC cannot be used on NOMMU */
123 int old_sleep = die_sleep;
124 int old_x = xfunc_error_retval;
125 die_sleep = -1; /* special flag */
126 /* xfunc_die() checks for it */
128 rc = setjmp(die_jmp);
130 const struct bb_applet *old_a = current_applet;
132 applet_name = a->name;
133 // what else should we save/restore?
134 rc = a->main(argc, argv);
135 current_applet = old_a;
136 applet_name = old_a->name;
138 /* xfunc died in NOFORK applet */
143 die_sleep = old_sleep;
144 xfunc_error_retval = old_x;
147 #ifndef BB_NOMMU /* MMU only */
148 /* a->noexec is true */
154 run_current_applet_and_exit(argc, argv);
161 #else /* !FEATURE_EXEC_PREFER_APPLETS */
163 #endif /* FEATURE_EXEC_PREFER_APPLETS */
168 #if 0 //ndef BB_NOMMU
169 // Die with an error message if we can't daemonize.
170 void xdaemon(int nochdir, int noclose)
172 if (daemon(nochdir, noclose))
173 bb_perror_msg_and_die("daemon");
177 #if 0 // def BB_NOMMU
178 void vfork_daemon_rexec(int nochdir, int noclose, char **argv)
182 /* Maybe we are already re-execed and come here again? */
192 /* if "/dev/null" doesn't exist, bail out! */
193 fd = xopen(bb_dev_null, O_RDWR);
194 dup2(fd, STDIN_FILENO);
195 dup2(fd, STDOUT_FILENO);
196 dup2(fd, STDERR_FILENO);
203 /* Make certain we are not a session leader, or else we
204 * might reacquire a controlling terminal */
207 /* High-order bit of first char in argv[0] is a hidden
208 * "we have (alrealy) re-execed, don't do it again" flag */
210 execv(CONFIG_BUSYBOX_EXEC_PATH, argv);
211 bb_perror_msg_and_die("exec %s", CONFIG_BUSYBOX_EXEC_PATH);
213 bb_perror_msg_and_die("vfork");
214 default: /* parent */
218 #endif /* BB_NOMMU */
221 void forkexit_or_rexec(char **argv)
224 /* Maybe we are already re-execed and come here again? */
229 if (pid < 0) /* wtf? */
230 bb_perror_msg_and_die("vfork");
231 if (pid) /* parent */
233 /* child - re-exec ourself */
234 /* high-order bit of first char in argv[0] is a hidden
235 * "we have (alrealy) re-execed, don't do it again" flag */
237 execv(CONFIG_BUSYBOX_EXEC_PATH, argv);
238 bb_perror_msg_and_die("exec %s", CONFIG_BUSYBOX_EXEC_PATH);
241 /* Dance around (void)...*/
242 #undef forkexit_or_rexec
243 void forkexit_or_rexec(void)
247 if (pid < 0) /* wtf? */
248 bb_perror_msg_and_die("fork");
249 if (pid) /* parent */
253 #define forkexit_or_rexec(argv) forkexit_or_rexec()
257 /* Due to a #define in libbb.h on MMU systems we actually have 1 argument -
258 * char **argv "vanishes" */
259 void bb_daemonize_or_rexec(int flags, char **argv)
263 fd = xopen(bb_dev_null, O_RDWR);
265 if (flags & DAEMON_CHDIR_ROOT)
268 if (flags & DAEMON_DEVNULL_STDIO) {
274 while ((unsigned)fd < 2)
275 fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
277 if (!(flags & DAEMON_ONLY_SANITIZE)) {
278 forkexit_or_rexec(argv);
279 /* if daemonizing, make sure we detach from stdio */
287 if (flags & DAEMON_CLOSE_EXTRA_FDS)
289 close(fd--); /* close everything after fd#2 */
292 void bb_sanitize_stdio(void)
294 bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE, NULL);