revert last two commits. vfork cannot be used in subroutine,

it trashes stack on return

15 files changed, 55 insertions, 50 deletions

diff --git a/archival/libunarchive/open_transformer.c b/archival/libunarchive/open_transformer.c
index 0738e3db1..a6bc62321 100644
--- a/archival/libunarchive/open_transformer.c
+++ b/archival/libunarchive/open_transformer.c
@@ -20,7 +20,16 @@ int FAST_FUNC open_transformer(int src_fd,
 
         xpiped_pair(fd_pipe);
 
-        pid = BB_MMU ? xfork() : xvfork();
+#if BB_MMU
+        pid = fork();
+        if (pid == -1)
+                bb_perror_msg_and_die("can't fork");
+#else
+        pid = vfork();
+        if (pid == -1)
+                bb_perror_msg_and_die("can't vfork");
+#endif
+
         if (pid == 0) {
                 /* child process */
                 close(fd_pipe.rd); /* We don't want to read from the parent */
diff --git a/archival/tar.c b/archival/tar.c
index 17ac6c55a..526edb69d 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -536,7 +536,9 @@ static void NOINLINE vfork_compressor(int tar_fd, int gzip)
         (void) &zip_exec;
 #endif
 
-        gzipPid = xvfork();
+        gzipPid = vfork();
+        if (gzipPid < 0)
+                bb_perror_msg_and_die("can't vfork");
 
         if (gzipPid == 0) {
                 /* child */
diff --git a/debianutils/start_stop_daemon.c b/debianutils/start_stop_daemon.c
index f10572ddf..459fb77e0 100644
--- a/debianutils/start_stop_daemon.c
+++ b/debianutils/start_stop_daemon.c
@@ -404,7 +404,9 @@ int start_stop_daemon_main(int argc ATTRIBUTE_UNUSED, char **argv)
                 /* DAEMON_DEVNULL_STDIO is superfluous -
                  * it's always done by bb_daemonize() */
 #else
-                pid_t pid = xvfork();
+                pid_t pid = vfork();
+                if (pid < 0) /* error */
+                        bb_perror_msg_and_die("vfork");
                 if (pid != 0) {
                         /* parent */
                         /* why _exit? the child may have changed the stack,
diff --git a/include/libbb.h b/include/libbb.h
index 67eef6dbb..54601f87b 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -719,11 +719,6 @@ int bb_execvp(const char *file, char *const argv[]) FAST_FUNC;
 #define BB_EXECLP(prog,cmd,...) execlp(prog,cmd, __VA_ARGS__)
 #endif
 
-#if BB_MMU
-pid_t xfork(void) FAST_FUNC;
-#endif
-pid_t xvfork(void) FAST_FUNC;
-
 /* NOMMU friendy fork+exec */
 pid_t spawn(char **argv) FAST_FUNC;
 pid_t xspawn(char **argv) FAST_FUNC;
diff --git a/libbb/Kbuild b/libbb/Kbuild
index 5ace87cad..5cbecd537 100644
--- a/libbb/Kbuild
+++ b/libbb/Kbuild
@@ -109,7 +109,6 @@ lib-y += xfunc_die.o
 lib-y += xgetcwd.o
 lib-y += xgethostbyname.o
 lib-y += xreadlink.o
-lib-y += xvfork.o
 
 # conditionally compiled objects:
 lib-$(CONFIG_FEATURE_MOUNT_LOOP) += loop.o
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index 989e9b841..37d4c274e 100644
--- a/libbb/vfork_daemon_rexec.c
+++ b/libbb/vfork_daemon_rexec.c
@@ -226,7 +226,9 @@ void FAST_FUNC forkexit_or_rexec(char **argv)
         if (re_execed)
                 return;
 
-        pid = xvfork();
+        pid = vfork();
+        if (pid < 0) /* wtf? */
+                bb_perror_msg_and_die("vfork");
         if (pid) /* parent */
                 exit(EXIT_SUCCESS);
         /* child - re-exec ourself */
@@ -238,7 +240,9 @@ void FAST_FUNC forkexit_or_rexec(char **argv)
 void FAST_FUNC forkexit_or_rexec(void)
 {
         pid_t pid;
-        pid = xfork();
+        pid = fork();
+        if (pid < 0) /* wtf? */
+                bb_perror_msg_and_die("fork");
         if (pid) /* parent */
                 exit(EXIT_SUCCESS);
         /* child */
diff --git a/libbb/xvfork.c b/libbb/xvfork.c
deleted file mode 100644
index 3fbd0c1ed..000000000
--- a/libbb/xvfork.c
+++ /dev/null
@@ -1,28 +0,0 @@
-/* vi: set sw=4 ts=4: */
-/*
- * Utility routines.
- *
- * Copyright (C) 2007 Denys Vlasenko
- *
- * Licensed under GPL version 2, see file LICENSE in this tarball for details.
- */
-
-#include "libbb.h"
-
-pid_t FAST_FUNC xvfork(void)
-{
-        pid_t pid = vfork();
-        if (pid < 0)
-                bb_perror_msg_and_die("vfork");
-        return pid;
-}
-
-#if BB_MMU
-pid_t FAST_FUNC xfork(void)
-{
-        pid_t pid = fork();
-        if (pid < 0)
-                bb_perror_msg_and_die("vfork" + 1);
-        return pid;
-}
-#endif
diff --git a/miscutils/crontab.c b/miscutils/crontab.c
index 4bba9fb44..dc3179dac 100644
--- a/miscutils/crontab.c
+++ b/miscutils/crontab.c
@@ -38,8 +38,10 @@ static void change_user(const struct passwd *pas)
 static void edit_file(const struct passwd *pas, const char *file)
 {
         const char *ptr;
-        int pid = xvfork();
+        int pid = vfork();
 
+        if (pid < 0) /* failure */
+                bb_perror_msg_and_die("vfork");
         if (pid) { /* parent */
                 wait4pid(pid);
                 return;
@@ -63,7 +65,9 @@ static int open_as_user(const struct passwd *pas, const char *file)
         pid_t pid;
         char c;
 
-        pid = xvfork();
+        pid = vfork();
+        if (pid < 0) /* ERROR */
+                bb_perror_msg_and_die("vfork");
         if (pid) { /* PARENT */
                 if (wait4pid(pid) == 0) {
                         /* exitcode 0: child says it can read */
diff --git a/miscutils/time.c b/miscutils/time.c
index 104548c23..a6d158c53 100644
--- a/miscutils/time.c
+++ b/miscutils/time.c
@@ -372,7 +372,9 @@ static void run_command(char *const *cmd, resource_t *resp)
         void (*quit_signal)(int);
 
         resp->elapsed_ms = monotonic_us() / 1000;
-        pid = xvfork();         /* Run CMD as child process.  */
+        pid = vfork();          /* Run CMD as child process.  */
+        if (pid < 0)
+                bb_error_msg_and_die("cannot fork");
         if (pid == 0) { /* If child.  */
                 /* Don't cast execvp arguments; that causes errors on some systems,
                    versus merely warnings if the cast is left off.  */
diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index 8caff3f4d..c12391863 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -1008,9 +1008,12 @@ static int popen2(FILE **in, FILE **out, char *command, char *param)
         xpiped_pair(outfd);
 
         fflush(NULL);
-        pid = xvfork();
+        pid = vfork();
 
-        if (pid == 0) { /* child */
+        switch (pid) {
+        case -1:  /* failure */
+                bb_perror_msg_and_die("vfork");
+        case 0:  /* child */
                 /* NB: close _first_, then move fds! */
                 close(infd.wr);
                 close(outfd.rd);
diff --git a/networking/inetd.c b/networking/inetd.c
index 0028078db..08c09953b 100644
--- a/networking/inetd.c
+++ b/networking/inetd.c
@@ -1303,7 +1303,7 @@ int inetd_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                         pid = vfork();
 
                                 if (pid < 0) { /* fork error */
-                                        bb_perror_msg(BB_MMU ? "vfork" + 1 : "vfork");
+                                        bb_perror_msg("fork");
                                         sleep(1);
                                         restore_sigmask(&omask);
                                         maybe_close(accepted_fd);
diff --git a/networking/sendmail.c b/networking/sendmail.c
index c195cc021..1c23ca290 100644
--- a/networking/sendmail.c
+++ b/networking/sendmail.c
@@ -120,6 +120,15 @@ static void signal_handler(int signo)
 #undef err
 }
 
+/* libbb candidate */
+static pid_t vfork_or_die(void)
+{
+        pid_t pid = vfork();
+        if (pid < 0)
+                bb_perror_msg_and_die("vfork");
+        return pid;
+}
+
 static void launch_helper(const char **argv)
 {
         // setup vanilla unidirectional pipes interchange
@@ -128,7 +137,7 @@ static void launch_helper(const char **argv)
 
         xpipe(pipes);
         xpipe(pipes+2);
-        helper_pid = xvfork();
+        helper_pid = vfork_or_die();
         idx = (!helper_pid) * 2;
         xdup2(pipes[idx], STDIN_FILENO);
         xdup2(pipes[3-idx], STDOUT_FILENO);
diff --git a/shell/hush.c b/shell/hush.c
index 27fab0d1b..72186f970 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1902,7 +1902,7 @@ static int run_pipe(struct pipe *pi)
 #endif
                 if (child->pid < 0) { /* [v]fork failed */
                         /* Clearly indicate, was it fork or vfork */
-                        bb_perror_msg(BB_MMU ? "vfork" + 1 : "vfork");
+                        bb_perror_msg(BB_MMU ? "fork" : "vfork");
                 } else {
                         pi->alive_progs++;
 #if ENABLE_HUSH_JOB
@@ -3096,7 +3096,9 @@ static FILE *generate_stream_from_list(struct pipe *head)
  * huge=`cat TESTFILE` # will block here forever
  * echo OK
  */
-        pid = BB_MMU ? xfork() : xvfork();
+        pid = BB_MMU ? fork() : vfork();
+        if (pid < 0)
+                bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork");
         if (pid == 0) { /* child */
                 if (ENABLE_HUSH_JOB)
                         die_sleep = 0; /* let nofork's xfuncs die */
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 664d24fd8..3b77af728 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -890,7 +890,6 @@ get_mountport(struct pmap *pm_mnt,
 }
 
 #if BB_MMU
-/* Unlike bb_daemonize(), parent does NOT exit here, but returns 0 */
 static int daemonize(void)
 {
         int fd;
diff --git a/util-linux/script.c b/util-linux/script.c
index a6c1ab88a..e70294e6c 100644
--- a/util-linux/script.c
+++ b/util-linux/script.c
@@ -87,7 +87,10 @@ int script_main(int argc ATTRIBUTE_UNUSED, char **argv)
 
         /* TODO: SIGWINCH? pass window size changes down to slave? */
 
-        child_pid = xvfork();
+        child_pid = vfork();
+        if (child_pid < 0) {
+                bb_perror_msg_and_die("vfork");
+        }
 
         if (child_pid) {
                 /* parent */