[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit

Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/app/busybox/src/miscutils/setsid.c b/ap/app/busybox/src/miscutils/setsid.c
new file mode 100644
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+++ b/ap/app/busybox/src/miscutils/setsid.c
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+/* vi: set sw=4 ts=4: */
+/*
+ * setsid.c -- execute a command in a new session
+ * Rick Sladkey <jrs@world.std.com>
+ * In the public domain.
+ *
+ * 1999-02-22 Arkadiusz Mickiewicz <misiek@pld.ORG.PL>
+ * - added Native Language Support
+ *
+ * 2001-01-18 John Fremlin <vii@penguinpowered.com>
+ * - fork in case we are process group leader
+ *
+ * 2004-11-12 Paul Fox
+ * - busyboxed
+ */
+
+//usage:#define setsid_trivial_usage
+//usage:       "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."
+
+#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();
+
+	/* 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 (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);
+		}
+
+		/* child */
+		/* now there should be no error: */
+		setsid();
+	}
+
+	argv++;
+	BB_EXECVP_or_die(argv);
+}