setsid: implement -c

function                                             old     new   delta
setsid_main                                           53      96     +43
packed_usage                                       30846   30833     -13

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

1 files changed, 13 insertions, 6 deletions

diff --git a/miscutils/setsid.c b/miscutils/setsid.c
index 637081b6c..1b27377b2 100644
--- a/miscutils/setsid.c
+++ b/miscutils/setsid.c
@@ -15,19 +15,22 @@
  */
 
 //usage:#define setsid_trivial_usage
-//usage:       "PROG ARGS"
+//usage:       "[-c] PROG ARGS"
 //usage:#define setsid_full_usage "\n\n"
 //usage:       "Run PROG in a new session. PROG will have no controlling terminal\n"
-//usage:       "and will not be affected by keyboard signals (Ctrl-C etc).\n"
-//usage:       "See setsid(2) for details."
+//usage:       "and will not be affected by keyboard signals (^C etc).\n"
+//usage:     "\n        -c      Set controlling terminal to stdin"
 
 #include "libbb.h"
 
 int setsid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int setsid_main(int argc UNUSED_PARAM, char **argv)
 {
-        if (!argv[1])
-                bb_show_usage();
+        unsigned opt;
+
+        opt_complementary = "-1"; /* at least one arg */
+        opt = getopt32(argv, "c");
+        argv += optind;
 
         /* setsid() is allowed only when we are not a process group leader.
          * Otherwise our PID serves as PGID of some existing process group
@@ -61,6 +64,10 @@ int setsid_main(int argc UNUSED_PARAM, char **argv)
                 setsid();
         }
 
-        argv++;
+        if (opt) {
+                /* -c: set (with stealing) controlling tty */
+                ioctl(0, TIOCSCTTY, 1);
+        }
+
         BB_EXECVP_or_die(argv);
 }