setsid: check for setsid error directly

function                                             old     new   delta
setsid_main                                           74      66      -8

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

1 files changed, 17 insertions, 4 deletions

diff --git a/miscutils/setsid.c b/miscutils/setsid.c
index d7de1f149..fd3283e30 100644
--- 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]);