toolbox: Add nohup command

Change-Id: I2f7d9934b54d98886d7a6205ea122d9ce91066ec
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/toolbox/Android.mk b/toolbox/Android.mk
index 75ce53f..c5890b2 100644
--- a/toolbox/Android.mk
+++ b/toolbox/Android.mk
@@ -69,7 +69,8 @@
 	swapon \
 	swapoff \
 	mkswap \
-	readlink
+	readlink \
+	nohup
 
 ifneq (,$(filter userdebug eng,$(TARGET_BUILD_VARIANT)))
 TOOLS += r
diff --git a/toolbox/nohup.c b/toolbox/nohup.c
new file mode 100644
index 0000000..363999d
--- /dev/null
+++ b/toolbox/nohup.c
@@ -0,0 +1,26 @@
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int nohup_main(int argc, char *argv[])
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: %s [-n] program args...\n", argv[0]);
+        return EXIT_FAILURE;
+    }
+    signal(SIGHUP, SIG_IGN);
+    argv++;
+    if (strcmp(argv[0], "-n") == 0) {
+        argv++;
+        signal(SIGINT, SIG_IGN);
+        signal(SIGSTOP, SIG_IGN);
+        signal(SIGTTIN, SIG_IGN);
+        signal(SIGTTOU, SIG_IGN);
+        signal(SIGQUIT, SIG_IGN);
+        signal(SIGTERM, SIG_IGN);
+    }
+    execvp(argv[0], argv);
+    perror(argv[0]);
+    return EXIT_FAILURE;
+}