*
* 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 "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. */
* 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;
}
-#if ENABLE_FEATURE_PREFER_APPLETS
-void FAST_FUNC save_nofork_data(struct nofork_save_area *save)
+#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);
+}
+
+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)
{
memcpy(&save->die_jmp, &die_jmp, sizeof(die_jmp));
+ save->die_func = die_func;
save->applet_name = applet_name;
- save->xfunc_error_retval = xfunc_error_retval;
save->option_mask32 = option_mask32;
- save->die_sleep = die_sleep;
- save->saved = 1;
+ save->logmode = logmode;
+ save->xfunc_error_retval = xfunc_error_retval;
}
-
-void FAST_FUNC restore_nofork_data(struct nofork_save_area *save)
+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;
- xfunc_error_retval = save->xfunc_error_retval;
option_mask32 = save->option_mask32;
- die_sleep = save->die_sleep;
+ logmode = save->logmode;
+ xfunc_error_retval = save->xfunc_error_retval;
}
-int FAST_FUNC run_nofork_applet_prime(struct nofork_save_area *old, int applet_no, char **argv)
+int FAST_FUNC run_nofork_applet(int applet_no, char **argv)
{
int rc, argc;
+ struct nofork_save_area old;
- applet_name = APPLET_NAME(applet_no);
+ save_nofork_data(&old);
+ logmode = LOGMODE_STDIO;
xfunc_error_retval = EXIT_FAILURE;
-
- /* 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;
-
/* 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 */
+ GETOPT_RESET();
argc = 1;
while (argv[argc])
argc++;
+ /* 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);
-
- /* The whole reason behind nofork_save_area is that <applet>_main
- * may exit non-locally! For example, in hush Ctrl-Z tries
- * (modulo bugs) to dynamically create a child (backgrounded task)
- * if it detects that Ctrl-Z was pressed when a NOFORK was running.
- * Testcase: interactive "rm -i".
- * Don't fool yourself into thinking "and <applet>_main() returns
- * quickly here" and removing "useless" nofork_save_area code. */
-
- } else { /* xfunc died in NOFORK applet */
- /* in case they meant to return 0... */
- if (rc == -2222)
- rc = 0;
+ /* Important for shells: `which CMD` was failing */
+ fflush_all();
+ } else {
+ /* xfunc died in NOFORK applet */
}
/* Restoring some globals */
- restore_nofork_data(old);
-
+ restore_nofork_data(&old);
/* Other globals can be simply reset to defaults */
-#ifdef __GLIBC__
- optind = 0;
-#else /* BSD style */
- optind = 1;
-#endif
+ GETOPT_RESET();
return rc & 0xff; /* don't confuse people with "exitcodes" >255 */
}
-
-int FAST_FUNC run_nofork_applet(int applet_no, char **argv)
-{
- struct nofork_save_area old;
-
- /* Saving globals */
- save_nofork_data(&old);
- return run_nofork_applet_prime(&old, applet_no, argv);
-}
-#endif /* FEATURE_PREFER_APPLETS */
+#endif /* FEATURE_PREFER_APPLETS || FEATURE_SH_NOFORK */
int FAST_FUNC spawn_and_wait(char **argv)
{
int rc;
-#if ENABLE_FEATURE_PREFER_APPLETS
+#if ENABLE_FEATURE_PREFER_APPLETS && (NUM_APPLETS > 1)
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 (a >= 0) {
if (APPLET_IS_NOFORK(a))
-#endif
- {
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);
}
-#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
}
#endif /* FEATURE_PREFER_APPLETS */
rc = spawn(argv);
/* 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 */
return pid;
fd = dup(fd); /* have 0,1,2 open at least to /dev/null */
if (!(flags & DAEMON_ONLY_SANITIZE)) {
+
+ /* fflush_all(); - add it in fork_or_rexec() if necessary */
+
if (fork_or_rexec(argv))
- exit(EXIT_SUCCESS); /* parent */
- /* if daemonizing, make sure we detach from stdio & ctty */
+ _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 */
+ }
}
while (fd > 2) {
close(fd--);
projects / oweals / busybox.git / blobdiff