*
* Modified for uClibc by Erik Andersen <andersee@debian.org>
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-#include <unistd.h>
-#include <stdio.h>
-#include <fcntl.h>
-#include <paths.h>
-#include "libbb.h"
+#include "busybox.h" /* uses applet tables */
+/* This does a fork/exec in one call, using vfork(). Returns PID of new child,
+ * -1 for failure. Runs argv[0], searching path if that has no / in it. */
+pid_t FAST_FUNC spawn(char **argv)
+{
+ /* Compiler should not optimize stores here */
+ volatile int failed;
+ pid_t pid;
+
+ fflush_all();
+
+ /* Be nice to nommu machines. */
+ failed = 0;
+ pid = vfork();
+ if (pid < 0) /* error */
+ return pid;
+ if (!pid) { /* child */
+ /* This macro is ok - it doesn't do NOEXEC/NOFORK tricks */
+ BB_EXECVP(argv[0], argv);
+
+ /* We are (maybe) sharing a stack with blocked parent,
+ * let parent know we failed and then exit to unblock parent
+ * (but don't run atexit() stuff, which would screw up parent.)
+ */
+ failed = errno;
+ /* mount, for example, does not want the message */
+ /*bb_perror_msg("can't execute '%s'", argv[0]);*/
+ _exit(111);
+ }
+ /* parent */
+ /* Unfortunately, this is not reliable: according to standards
+ * vfork() can be equivalent to fork() and we won't see value
+ * of 'failed'.
+ * Interested party can wait on pid and learn exit code.
+ * If 111 - then it (most probably) failed to exec */
+ if (failed) {
+ safe_waitpid(pid, NULL, 0); /* prevent zombie */
+ errno = failed;
+ return -1;
+ }
+ return pid;
+}
+
+/* Die with an error message if we can't spawn a child process. */
+pid_t FAST_FUNC xspawn(char **argv)
+{
+ pid_t pid = spawn(argv);
+ if (pid < 0)
+ bb_simple_perror_msg_and_die(*argv);
+ return pid;
+}
-#ifdef BB_NOMMU
-void vfork_daemon_rexec(int nochdir, int noclose,
- int argc, char **argv, char *foreground_opt)
+#if ENABLE_FEATURE_PREFER_APPLETS
+struct nofork_save_area {
+ jmp_buf die_jmp;
+ const char *applet_name;
+ uint32_t option_mask32;
+ int die_sleep;
+ uint8_t xfunc_error_retval;
+};
+static void save_nofork_data(struct nofork_save_area *save)
+{
+ memcpy(&save->die_jmp, &die_jmp, sizeof(die_jmp));
+ save->applet_name = applet_name;
+ save->xfunc_error_retval = xfunc_error_retval;
+ save->option_mask32 = option_mask32;
+ save->die_sleep = die_sleep;
+}
+static void restore_nofork_data(struct nofork_save_area *save)
+{
+ memcpy(&die_jmp, &save->die_jmp, sizeof(die_jmp));
+ applet_name = save->applet_name;
+ xfunc_error_retval = save->xfunc_error_retval;
+ option_mask32 = save->option_mask32;
+ die_sleep = save->die_sleep;
+}
+
+int FAST_FUNC run_nofork_applet(int applet_no, char **argv)
+{
+ int rc, argc;
+ struct nofork_save_area old;
+
+ save_nofork_data(&old);
+
+ applet_name = APPLET_NAME(applet_no);
+
+ xfunc_error_retval = EXIT_FAILURE;
+
+ /* In case getopt() or getopt32() was already called:
+ * reset the libc getopt() function, which keeps internal state.
+ *
+ * BSD-derived getopt() functions require that optind be set to 1 in
+ * order to reset getopt() state. This used to be generally accepted
+ * way of resetting getopt(). However, glibc's getopt()
+ * has additional getopt() state beyond optind, and requires that
+ * optind be set to zero to reset its state. So the unfortunate state of
+ * affairs is that BSD-derived versions of getopt() misbehave if
+ * optind is set to 0 in order to reset getopt(), and glibc's getopt()
+ * will core dump if optind is set 1 in order to reset getopt().
+ *
+ * More modern versions of BSD require that optreset be set to 1 in
+ * order to reset getopt(). Sigh. Standards, anyone?
+ */
+#ifdef __GLIBC__
+ optind = 0;
+#else /* BSD style */
+ optind = 1;
+ /* optreset = 1; */
+#endif
+ /* optarg = NULL; opterr = 1; optopt = 63; - do we need this too? */
+ /* (values above are what they initialized to in glibc and uclibc) */
+ /* option_mask32 = 0; - not needed, no applet depends on it being 0 */
+
+ argc = 1;
+ while (argv[argc])
+ argc++;
+
+ /* Special flag for xfunc_die(). If xfunc will "die"
+ * in NOFORK applet, xfunc_die() sees negative
+ * die_sleep and longjmp here instead. */
+ die_sleep = -1;
+
+ rc = setjmp(die_jmp);
+ if (!rc) {
+ /* Some callers (xargs)
+ * need argv untouched because they free argv[i]! */
+ char *tmp_argv[argc+1];
+ memcpy(tmp_argv, argv, (argc+1) * sizeof(tmp_argv[0]));
+ /* Finally we can call NOFORK applet's main() */
+ rc = applet_main[applet_no](argc, tmp_argv);
+ } else { /* xfunc died in NOFORK applet */
+ /* in case they meant to return 0... */
+ if (rc == -2222)
+ rc = 0;
+ }
+
+ /* Restoring some globals */
+ restore_nofork_data(&old);
+
+ /* Other globals can be simply reset to defaults */
+#ifdef __GLIBC__
+ optind = 0;
+#else /* BSD style */
+ optind = 1;
+#endif
+
+ return rc & 0xff; /* don't confuse people with "exitcodes" >255 */
+}
+#endif /* FEATURE_PREFER_APPLETS */
+
+int FAST_FUNC spawn_and_wait(char **argv)
+{
+ int rc;
+#if ENABLE_FEATURE_PREFER_APPLETS
+ int a = find_applet_by_name(argv[0]);
+
+ if (a >= 0 && (APPLET_IS_NOFORK(a)
+# if BB_MMU
+ || APPLET_IS_NOEXEC(a) /* NOEXEC trick needs fork() */
+# endif
+ )) {
+# if BB_MMU
+ if (APPLET_IS_NOFORK(a))
+# endif
+ {
+ return run_nofork_applet(a, argv);
+ }
+# if BB_MMU
+ /* MMU only */
+ /* a->noexec is true */
+ rc = fork();
+ if (rc) /* parent or error */
+ return wait4pid(rc);
+ /* child */
+ xfunc_error_retval = EXIT_FAILURE;
+ run_applet_no_and_exit(a, argv);
+# endif
+ }
+#endif /* FEATURE_PREFER_APPLETS */
+ rc = spawn(argv);
+ return wait4pid(rc);
+}
+
+#if !BB_MMU
+void FAST_FUNC re_exec(char **argv)
+{
+ /* high-order bit of first char in argv[0] is a hidden
+ * "we have (already) re-execed, don't do it again" flag */
+ argv[0][0] |= 0x80;
+ execv(bb_busybox_exec_path, argv);
+ bb_perror_msg_and_die("can't execute '%s'", bb_busybox_exec_path);
+}
+
+pid_t FAST_FUNC fork_or_rexec(char **argv)
+{
+ pid_t pid;
+ /* Maybe we are already re-execed and come here again? */
+ if (re_execed)
+ return 0;
+ pid = xvfork();
+ if (pid) /* parent */
+ return pid;
+ /* child - re-exec ourself */
+ re_exec(argv);
+}
+#endif
+
+/* Due to a #define in libbb.h on MMU systems we actually have 1 argument -
+ * char **argv "vanishes" */
+void FAST_FUNC bb_daemonize_or_rexec(int flags, char **argv)
{
int fd;
- char **vfork_args;
- int a = 0;
- setsid();
+ if (flags & DAEMON_CHDIR_ROOT)
+ xchdir("/");
- if (!nochdir)
- chdir("/");
+ if (flags & DAEMON_DEVNULL_STDIO) {
+ close(0);
+ close(1);
+ close(2);
+ }
- if (!noclose && (fd = open(bb_dev_null, O_RDWR, 0)) != -1) {
- dup2(fd, STDIN_FILENO);
- dup2(fd, STDOUT_FILENO);
- dup2(fd, STDERR_FILENO);
- if (fd > 2)
- close(fd);
+ fd = open(bb_dev_null, O_RDWR);
+ if (fd < 0) {
+ /* NB: we can be called as bb_sanitize_stdio() from init
+ * or mdev, and there /dev/null may legitimately not (yet) exist!
+ * Do not use xopen above, but obtain _ANY_ open descriptor,
+ * even bogus one as below. */
+ fd = xopen("/", O_RDONLY); /* don't believe this can fail */
}
- vfork_args = xcalloc(sizeof(char *), argc + 3);
- vfork_args[a++] = "/bin/busybox";
- while(*argv) {
- vfork_args[a++] = *argv;
- argv++;
+ while ((unsigned)fd < 2)
+ fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
+
+ if (!(flags & DAEMON_ONLY_SANITIZE)) {
+ if (fork_or_rexec(argv))
+ exit(EXIT_SUCCESS); /* parent */
+ /* if daemonizing, detach from stdio & ctty */
+ setsid();
+ dup2(fd, 0);
+ dup2(fd, 1);
+ dup2(fd, 2);
+ if (flags & DAEMON_DOUBLE_FORK) {
+ /* On Linux, session leader can acquire ctty
+ * unknowingly, by opening a tty.
+ * Prevent this: stop being a session leader.
+ */
+ if (fork_or_rexec(argv))
+ exit(EXIT_SUCCESS); /* parent */
+ }
}
- vfork_args[a] = foreground_opt;
- switch (vfork()) {
- case 0: /* child */
- /* Make certain we are not a session leader, or else we
- * might reacquire a controlling terminal */
- if (vfork())
- _exit(0);
- execv(vfork_args[0], vfork_args);
- bb_perror_msg_and_die("execv %s", vfork_args[0]);
- case -1: /* error */
- bb_perror_msg_and_die("vfork");
- default: /* parent */
- exit(0);
+ while (fd > 2) {
+ close(fd--);
+ if (!(flags & DAEMON_CLOSE_EXTRA_FDS))
+ return;
+ /* else close everything after fd#2 */
}
}
-#endif /* BB_NOMMU */
+
+void FAST_FUNC bb_sanitize_stdio(void)
+{
+ bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE, NULL);
+}
projects / platform / upstream / busybox.git / blobdiff