Changeset 3621 in MondoRescue for branches/3.3/mindi-busybox/miscutils/setsid.c

Timestamp:

Dec 20, 2016, 4:07:32 PM (7 years ago)

Author:

Bruno Cornec

Message:

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.

Location:

branches/3.3

Files:

• . (copied) (copied from branches/3.2 )
• mindi-busybox/miscutils/setsid.c (modified) (4 diffs)

branches/3.3/mindi-busybox/miscutils/setsid.c

@@ -16 +16 @@
 
 //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"
@@ -27 +27 @@
 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"); /* +: stop on first non-opt */
+    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
-     * and cannot be used as PGID of a new process group. */
+     * and cannot be used as PGID of a new process group.
+     *
+     * Example: setsid() below fails when run alone in interactive shell:
+     *  $ setsid PROG
+     * because shell's child (setsid) is put in a new process group.
+     * But doesn't fail if shell is not interactive
+     * (and therefore doesn't create process groups for pipes),
+     * or if setsid is not the first process in the process group:
+     *  $ true | setsid PROG
+     * or if setsid is executed in backquotes (`setsid PROG`)...
+     */
     if (setsid() < 0) {
         pid_t pid = fork_or_rexec(argv);
@@ -44 +57 @@
              * does not do such trick.
              */
-            exit(EXIT_SUCCESS);
+            return EXIT_SUCCESS;
         }
 
@@ -52 +65 @@
     }
 
-    argv++;
+    if (opt) {
+        /* -c: set (with stealing) controlling tty */
+        ioctl(0, TIOCSCTTY, 1);
+    }
+
     BB_EXECVP_or_die(argv);
 }