*
* 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 <paths.h>
-#include "libbb.h"
+#include "busybox.h" /* uses applet tables */
+#include "NUM_APPLETS.h"
/* 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 spawn(char **argv)
+pid_t FAST_FUNC spawn(char **argv)
{
/* Compiler should not optimize stores here */
volatile int failed;
pid_t pid;
-// Ain't it a good place to fflush(NULL)?
+ fflush_all();
/* Be nice to nommu machines. */
failed = 0;
* (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 */
* 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;
}
}
/* Die with an error message if we can't spawn a child process. */
-pid_t xspawn(char **argv)
+pid_t FAST_FUNC xspawn(char **argv)
{
pid_t pid = spawn(argv);
- if (pid < 0) bb_perror_msg_and_die("%s", *argv);
+ if (pid < 0)
+ bb_simple_perror_msg_and_die(*argv);
return pid;
}
+#if ENABLE_FEATURE_PREFER_APPLETS \
+ || ENABLE_FEATURE_SH_NOFORK
+static jmp_buf die_jmp;
+static void jump(void)
+{
+ /* Special case. We arrive here if NOFORK applet
+ * calls xfunc, which then decides to die.
+ * We don't die, but jump instead back to caller.
+ * NOFORK applets still cannot carelessly call xfuncs:
+ * p = xmalloc(10);
+ * q = xmalloc(10); // BUG! if this dies, we leak p!
+ */
+ /* | 0x100 allows to pass zero exitcode (longjmp can't pass 0).
+ * This works because exitcodes are bytes,
+ * run_nofork_applet() ensures that by "& 0xff" */
+ longjmp(die_jmp, xfunc_error_retval | 0x100);
+}
-
-#if 0 //ndef BB_NOMMU
-// Die with an error message if we can't daemonize.
-void xdaemon(int nochdir, int noclose)
+struct nofork_save_area {
+ jmp_buf die_jmp;
+ void (*die_func)(void);
+ const char *applet_name;
+ uint32_t option_mask32;
+ smallint logmode;
+ uint8_t xfunc_error_retval;
+};
+static void save_nofork_data(struct nofork_save_area *save)
{
- if (daemon(nochdir, noclose))
- bb_perror_msg_and_die("daemon");
+ memcpy(&save->die_jmp, &die_jmp, sizeof(die_jmp));
+ save->die_func = die_func;
+ save->applet_name = applet_name;
+ save->option_mask32 = option_mask32;
+ save->logmode = logmode;
+ save->xfunc_error_retval = xfunc_error_retval;
+}
+static void restore_nofork_data(struct nofork_save_area *save)
+{
+ memcpy(&die_jmp, &save->die_jmp, sizeof(die_jmp));
+ die_func = save->die_func;
+ applet_name = save->applet_name;
+ option_mask32 = save->option_mask32;
+ logmode = save->logmode;
+ xfunc_error_retval = save->xfunc_error_retval;
}
-#endif
-#if 0 // def BB_NOMMU
-void vfork_daemon_rexec(int nochdir, int noclose, char **argv)
+int FAST_FUNC run_nofork_applet(int applet_no, char **argv)
{
- int fd;
+ int rc, argc;
+ struct nofork_save_area old;
- /* Maybe we are already re-execed and come here again? */
- if (re_execed)
- return;
+ save_nofork_data(&old);
- setsid();
+ logmode = LOGMODE_STDIO;
+ xfunc_error_retval = EXIT_FAILURE;
+ /* In case getopt() or getopt32() was already called:
+ * reset the libc getopt() function, which keeps internal state.
+ */
+ GETOPT_RESET();
- if (!nochdir)
- xchdir("/");
+ argc = 1;
+ while (argv[argc])
+ argc++;
- if (!noclose) {
- /* if "/dev/null" doesn't exist, bail out! */
- fd = xopen(bb_dev_null, O_RDWR);
- dup2(fd, STDIN_FILENO);
- dup2(fd, STDOUT_FILENO);
- dup2(fd, STDERR_FILENO);
- while (fd > 2)
- close(fd--);
+ /* If xfunc "dies" in NOFORK applet, die_func longjmp's here instead */
+ die_func = jump;
+ 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]));
+ applet_name = tmp_argv[0];
+ /* Finally we can call NOFORK applet's main() */
+ rc = applet_main[applet_no](argc, tmp_argv);
+ /* Important for shells: `which CMD` was failing */
+ fflush_all();
+ } else {
+ /* xfunc died in NOFORK applet */
}
- 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);
- /* High-order bit of first char in argv[0] is a hidden
- * "we have (alrealy) re-execed, don't do it again" flag */
- argv[0][0] |= 0x80;
- execv(CONFIG_BUSYBOX_EXEC_PATH, argv);
- bb_perror_msg_and_die("exec %s", CONFIG_BUSYBOX_EXEC_PATH);
- case -1: /* error */
- bb_perror_msg_and_die("vfork");
- default: /* parent */
- exit(0);
- }
+ /* Restoring some globals */
+ restore_nofork_data(&old);
+ /* Other globals can be simply reset to defaults */
+ GETOPT_RESET();
+
+ return rc & 0xff; /* don't confuse people with "exitcodes" >255 */
}
-#endif /* BB_NOMMU */
+#endif /* FEATURE_PREFER_APPLETS || FEATURE_SH_NOFORK */
-#ifdef BB_NOMMU
-void forkexit_or_rexec(char **argv)
+int FAST_FUNC spawn_and_wait(char **argv)
{
- pid_t pid;
- /* Maybe we are already re-execed and come here again? */
- if (re_execed)
- return;
+ int rc;
+#if ENABLE_FEATURE_PREFER_APPLETS && (NUM_APPLETS > 1)
+ int a = find_applet_by_name(argv[0]);
- pid = vfork();
- if (pid < 0) /* wtf? */
- bb_perror_msg_and_die("vfork");
- if (pid) /* parent */
- exit(0);
- /* child - re-exec ourself */
+ if (a >= 0) {
+ if (APPLET_IS_NOFORK(a))
+ return run_nofork_applet(a, argv);
+# if BB_MMU /* NOEXEC needs fork(), thus this is done only on MMU machines: */
+ if (APPLET_IS_NOEXEC(a)) {
+ fflush_all();
+ rc = fork();
+ if (rc) /* parent or error */
+ return wait4pid(rc);
+
+ /* child */
+//TODO: prctl(PR_SET_NAME, (long)argv[0], 0, 0, 0);? [think pidof, pgrep, pkill]
+//Rewrite /proc/PID/cmdline? (need to save argv0 and length at init for this to work!)
+ /* reset some state and run without execing */
+
+ /* msg_eol = "\n"; - no caller needs this reinited yet */
+ logmode = LOGMODE_STDIO;
+ /* die_func = NULL; - needed if the caller is a shell,
+ * init, or a NOFORK applet. But none of those call us
+ * as of yet (and that should probably always stay true).
+ */
+ /* xfunc_error_retval and applet_name are init by: */
+ run_applet_no_and_exit(a, argv[0], 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 (alrealy) re-execed, don't do it again" flag */
+ * "we have (already) re-execed, don't do it again" flag */
argv[0][0] |= 0x80;
- execv(CONFIG_BUSYBOX_EXEC_PATH, argv);
- bb_perror_msg_and_die("exec %s", CONFIG_BUSYBOX_EXEC_PATH);
+ execv(bb_busybox_exec_path, argv);
+ bb_perror_msg_and_die("can't execute '%s'", bb_busybox_exec_path);
}
-#else
-/* Dance around (void)...*/
-#undef forkexit_or_rexec
-void forkexit_or_rexec(void)
+
+pid_t FAST_FUNC fork_or_rexec(char **argv)
{
pid_t pid;
- pid = fork();
- if (pid < 0) /* wtf? */
- bb_perror_msg_and_die("fork");
+ /* Maybe we are already re-execed and come here again? */
+ if (re_execed)
+ return 0;
+
+ /* fflush_all(); ? - so far all callers had no buffered output to flush */
+
+ pid = xvfork();
if (pid) /* parent */
- exit(0);
- /* child */
+ return pid;
+ /* child - re-exec ourself */
+ re_exec(argv);
}
-#define forkexit_or_rexec(argv) forkexit_or_rexec()
#endif
-
/* Due to a #define in libbb.h on MMU systems we actually have 1 argument -
* char **argv "vanishes" */
-void bb_daemonize_or_rexec(int flags, char **argv)
+void FAST_FUNC bb_daemonize_or_rexec(int flags, char **argv)
{
int fd;
- fd = xopen(bb_dev_null, O_RDWR);
-
if (flags & DAEMON_CHDIR_ROOT)
xchdir("/");
close(2);
}
+ 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 */
+ }
+
while ((unsigned)fd < 2)
fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
if (!(flags & DAEMON_ONLY_SANITIZE)) {
- forkexit_or_rexec(argv);
- /* if daemonizing, make sure we detach from stdio */
+
+ /* fflush_all(); - add it in fork_or_rexec() if necessary */
+
+ 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 */
+ }
}
- if (fd > 2)
+ while (fd > 2) {
close(fd--);
- if (flags & DAEMON_CLOSE_EXTRA_FDS)
- while (fd > 2)
- close(fd--); /* close everything after fd#2 */
+ if (!(flags & DAEMON_CLOSE_EXTRA_FDS))
+ return;
+ /* else close everything after fd#2 */
+ }
}
-void bb_sanitize_stdio(void)
+void FAST_FUNC bb_sanitize_stdio(void)
{
bb_daemonize_or_rexec(DAEMON_ONLY_SANITIZE, NULL);
}
projects / oweals / busybox.git / blobdiff