setsid: check for setsid error directly

function                                             old     new   delta
setsid_main                                           74      66      -8

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

diff --git a/miscutils/setsid.c b/miscutils/setsid.c
index d7de1f149726b179753f6cbf15595a9936a7baa0..fd3283e30def9d2ae0a98396fab42f62bf7a1505 100644 (file)
--- a/miscutils/setsid.c
+++ b/miscutils/setsid.c
@@ -25,11 +25,24 @@ int setsid_main(int argc UNUSED_PARAM, char **argv)
        /* setsid() is allowed only when we are not a process group leader.
         * Otherwise our PID serves as PGID of some existing process group
         * and cannot be used as PGID of a new process group. */
-       if (getpgrp() == getpid())
-               if (fork_or_rexec(argv))
-                       exit(EXIT_SUCCESS); /* parent */
+       if (setsid() < 0) {
+               pid_t pid = fork_or_rexec(argv);
+               if (pid != 0) {
+                       /* parent */
+                       /* TODO:
+                        * we can waitpid(pid, &status, 0) and then even
+                        * emulate exitcode, making the behavior consistent
+                        * in both forked and non forked cases.
+                        * However, the code is larger and upstream
+                        * does not do such trick.
+                        */
+                       exit(EXIT_SUCCESS);
+               }
 
-       setsid();  /* no error possible */
+               /* child */
+               /* now there should be no error: */
+               setsid();
+       }
 
        BB_EXECVP(argv[1], argv + 1);
        bb_simple_perror_msg_and_die(argv[1]);