*: code shrink and better "died from signal" reporting from wait4pid

function                                             old     new   delta
parse                                                964     967      +3
udhcp_run_script                                     670     665      -5
singlemount                                          911     906      -5
mount_it_now                                         360     355      -5
inotifyd_main                                        521     516      -5
xspawn                                                21       -     -21
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/4 up/down: 3/-41)             Total: -38 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

12 files changed, 24 insertions, 30 deletions

diff --git a/debianutils/run_parts.c b/debianutils/run_parts.c
index 2854a539c..37e8487e1 100644
--- a/debianutils/run_parts.c
+++ b/debianutils/run_parts.c
@@ -159,14 +159,14 @@ int run_parts_main(int argc UNUSED_PARAM, char **argv)
                         continue;
                 }
                 cmd[0] = name;
-                ret = wait4pid(spawn(cmd));
+                ret = spawn_and_wait(cmd);
                 if (ret == 0)
                         continue;
                 n = 1;
                 if (ret < 0)
                         bb_perror_msg("can't execute '%s'", name);
                 else /* ret > 0 */
-                        bb_error_msg("%s exited with code %d", name, ret);
+                        bb_error_msg("%s exited with code %d", name, ret & 0xff);
         }
 
         return n;
diff --git a/findutils/xargs.c b/findutils/xargs.c
index c7117771c..f5dbc7825 100644
--- a/findutils/xargs.c
+++ b/findutils/xargs.c
@@ -64,16 +64,9 @@ static int xargs_exec(char **args)
                 bb_error_msg("%s: exited with status 255; aborting", args[0]);
                 return 124;
         }
-/* Huh? I think we won't see this, ever. We don't wait with WUNTRACED!
-        if (WIFSTOPPED(status)) {
-                bb_error_msg("%s: stopped by signal %d",
-                        args[0], WSTOPSIG(status));
-                return 125;
-        }
-*/
-        if (status >= 1000) {
+        if (status >= 0x180) {
                 bb_error_msg("%s: terminated by signal %d",
-                        args[0], status - 1000);
+                        args[0], status - 0x180);
                 return 125;
         }
         if (status)
diff --git a/include/libbb.h b/include/libbb.h
index 044d09047..72d6c7dc8 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -812,21 +812,22 @@ int bb_execvp(const char *file, char *const argv[]) FAST_FUNC;
 #define BB_EXECLP(prog,cmd,...) execlp(prog,cmd, __VA_ARGS__)
 #endif
 
-/* NOMMU friendy fork+exec */
+/* NOMMU friendy fork+exec: */
 pid_t spawn(char **argv) FAST_FUNC;
 pid_t xspawn(char **argv) FAST_FUNC;
 
 pid_t safe_waitpid(pid_t pid, int *wstat, int options) FAST_FUNC;
-/* Unlike waitpid, waits ONLY for one process.
+pid_t wait_any_nohang(int *wstat) FAST_FUNC;
+/* wait4pid: unlike waitpid, waits ONLY for one process.
+ * Returns sig + 0x180 if child is killed by signal.
  * It's safe to pass negative 'pids' from failed [v]fork -
  * wait4pid will return -1 (and will not clobber [v]fork's errno).
  * IOW: rc = wait4pid(spawn(argv));
  *      if (rc < 0) bb_perror_msg("%s", argv[0]);
- *      if (rc > 0) bb_error_msg("exit code: %d", rc);
+ *      if (rc > 0) bb_error_msg("exit code: %d", rc & 0xff);
  */
 int wait4pid(pid_t pid) FAST_FUNC;
-pid_t wait_any_nohang(int *wstat) FAST_FUNC;
-/* wait4pid(spawn(argv)) + NOFORK/NOEXEC (if configured) */
+/* Same as wait4pid(spawn(argv)), but with NOFORK/NOEXEC if configured: */
 int spawn_and_wait(char **argv) FAST_FUNC;
 struct nofork_save_area {
         jmp_buf die_jmp;
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index 9be901722..07024f5f0 100644
--- a/libbb/vfork_daemon_rexec.c
+++ b/libbb/vfork_daemon_rexec.c
@@ -97,7 +97,7 @@ int FAST_FUNC wait4pid(pid_t pid)
         if (WIFEXITED(status))
                 return WEXITSTATUS(status);
         if (WIFSIGNALED(status))
-                return WTERMSIG(status) + 1000;
+                return WTERMSIG(status) + 0x180;
         return 0;
 }
 
diff --git a/mailutils/mime.c b/mailutils/mime.c
index 125ca01dd..ee147802e 100644
--- a/mailutils/mime.c
+++ b/mailutils/mime.c
@@ -357,7 +357,7 @@ static int parse(const char *boundary, char **argv)
                         if (opts & OPT_X) {
                                 signal(SIGPIPE, SIG_DFL);
                                 // exit if helper exited >0
-                                rc = wait4pid(pid);
+                                rc = (wait4pid(pid) & 0xff);
                                 if (rc)
                                         return rc+20;
                         }
diff --git a/miscutils/devfsd.c b/miscutils/devfsd.c
index 62f5de8b6..4ccb76d95 100644
--- a/miscutils/devfsd.c
+++ b/miscutils/devfsd.c
@@ -751,7 +751,7 @@ static void action_modload(const struct devfsd_notify_struct *info,
         argv[4] = concat_path_file("/dev", info->devname); /* device */
         argv[5] = NULL;
 
-        wait4pid(xspawn(argv));
+        spawn_and_wait(argv);
         free(argv[4]);
 }  /*  End Function action_modload  */
 
@@ -783,7 +783,7 @@ static void action_execute(const struct devfsd_notify_struct *info,
                 argv[count] = largv[count];
         }
         argv[count] = NULL;
-        wait4pid(spawn(argv));
+        spawn_and_wait(argv);
 }   /*  End Function action_execute  */
 
 
diff --git a/miscutils/inotifyd.c b/miscutils/inotifyd.c
index 999b5e309..271f3ade1 100644
--- a/miscutils/inotifyd.c
+++ b/miscutils/inotifyd.c
@@ -155,7 +155,7 @@ int inotifyd_main(int argc, char **argv)
                                 args[1] = events;
                                 args[2] = watches[ie->wd];
                                 args[3] = ie->len ? ie->name : NULL;
-                                wait4pid(xspawn((char **)args));
+                                spawn_and_wait((char **)args);
                                 // we are done if all files got final x event
                                 if (ie->mask & 0x8000) {
                                         if (--argc <= 0)
diff --git a/networking/ifplugd.c b/networking/ifplugd.c
index ac6607c91..62b135524 100644
--- a/networking/ifplugd.c
+++ b/networking/ifplugd.c
@@ -132,10 +132,10 @@ static int run_script(const char *action)
         argv[3] = (char*) G.extra_arg;
         argv[4] = NULL;
 
-        /* r < 0 - can't exec, 0 <= r < 1000 - exited, >1000 - killed by sig (r-1000) */
-        r = wait4pid(spawn(argv));
+        /* r < 0 - can't exec, 0 <= r < 0x180 - exited, >=0x180 - killed by sig (r-0x180) */
+        r = spawn_and_wait(argv);
 
-        bb_error_msg("exit code: %d", r);
+        bb_error_msg("exit code: %d", r & 0xff);
         return (option_mask32 & FLAG_IGNORE_RETVAL) ? 0 : r;
 
 #else /* insanity */
diff --git a/networking/ntpd.c b/networking/ntpd.c
index 04df3fa7f..6d9183a4b 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -772,7 +772,7 @@ static void run_script(const char *action, double offset)
 
         /* Don't want to wait: it may run hwclock --systohc, and that
          * may take some time (seconds): */
-        /*wait4pid(spawn(argv));*/
+        /*spawn_and_wait(argv);*/
         spawn(argv);
 
         unsetenv("stratum");
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
index 574c74f45..a74697c90 100644
--- a/networking/udhcp/script.c
+++ b/networking/udhcp/script.c
@@ -271,7 +271,7 @@ void FAST_FUNC udhcp_run_script(struct dhcp_packet *packet, const char *name)
         argv[0] = (char*) client_config.script;
         argv[1] = (char*) name;
         argv[2] = NULL;
-        wait4pid(spawn(argv));
+        spawn_and_wait(argv);
 
         for (curr = envp; *curr; curr++) {
                 log2(" %s", *curr);
diff --git a/networking/zcip.c b/networking/zcip.c
index db10d0a26..6b0b1c491 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -160,13 +160,13 @@ static int run(char *argv[3], const char *param, struct in_addr *ip)
         }
         bb_info_msg(fmt, argv[2], argv[0], addr);
 
-        status = wait4pid(spawn(argv + 1));
+        status = spawn_and_wait(argv + 1);
         if (status < 0) {
                 bb_perror_msg("%s %s %s" + 3, argv[2], argv[0]);
                 return -errno;
         }
         if (status != 0)
-                bb_error_msg("script %s %s failed, exitcode=%d", argv[1], argv[2], status);
+                bb_error_msg("script %s %s failed, exitcode=%d", argv[1], argv[2], status & 0xff);
         return status;
 }
 
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 620b14667..e24fc4024 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -456,7 +456,7 @@ static int mount_it_now(struct mntent *mp, long vfsflags, char *filteropts)
                                 args[rc++] = filteropts;
                         }
                         args[rc] = NULL;
-                        rc = wait4pid(spawn(args));
+                        rc = spawn_and_wait(args);
                         free(args[0]);
                         if (!rc)
                                 break;
@@ -1633,7 +1633,7 @@ static int singlemount(struct mntent *mp, int ignore_busy)
                 }
                 args[n++] = mp->mnt_dir;
                 args[n] = NULL;
-                rc = wait4pid(xspawn(args));
+                rc = spawn_and_wait(args);
                 goto report_error;
         }