[PATCH v9 07/19] index-helper: add --detach

[David Turner <dturner@twopensource.com>]

From: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

We detach after creating and opening the socket, because otherwise
we might return control to the shell before index-helper is ready to
accept commands.  This might lead to flaky tests.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: David Turner <dturner@twopensource.com>
---
 Documentation/git-index-helper.txt |  3 +++
 index-helper.c                     | 15 +++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-index-helper.txt b/Documentation/git-index-helper.txt
index 9c2f5eb..e144752 100644
--- a/Documentation/git-index-helper.txt
+++ b/Documentation/git-index-helper.txt
@@ -34,6 +34,9 @@ OPTIONS
 	for reading an index, but because it will happen in the
 	background, it's not noticable. `--strict` is enabled by default.
 
+--detach::
+	Detach from the shell.
+
 NOTES
 -----
 
diff --git a/index-helper.c b/index-helper.c
index 21fb431..7df7a97 100644
--- a/index-helper.c
+++ b/index-helper.c
@@ -17,7 +17,7 @@ struct shm {
 
 static struct shm shm_index;
 static struct shm shm_base_index;
-static int to_verify = 1;
+static int daemonized, to_verify = 1;
 
 static void log_warning(const char *warning, ...)
 {
@@ -59,6 +59,8 @@ static void cleanup_shm(void)
 
 static void cleanup(void)
 {
+	if (daemonized)
+		return;
 	unlink(git_path("index-helper.sock"));
 	cleanup_shm();
 }
@@ -311,7 +313,7 @@ static const char * const usage_text[] = {
 int main(int argc, char **argv)
 {
 	const char *prefix;
-	int idle_in_seconds = 600;
+	int idle_in_seconds = 600, detach = 0;
 	int fd;
 	struct strbuf socket_path = STRBUF_INIT;
 	struct option options[] = {
@@ -319,6 +321,7 @@ int main(int argc, char **argv)
 			    N_("exit if not used after some seconds")),
 		OPT_BOOL(0, "strict", &to_verify,
 			 "verify shared memory after creating"),
+		OPT_BOOL(0, "detach", &detach, "detach the process"),
 		OPT_END()
 	};
 
@@ -342,6 +345,14 @@ int main(int argc, char **argv)
 	if (fd < 0)
 		die_errno(_("could not set up index-helper socket"));
 
+	if (!freopen("/dev/null", "w", stderr))
+		die_errno("failed to redirect stderr to /dev/null");
+
+	if (!freopen("/dev/null", "w", stdout))
+		die_errno("failed to redirect stdout to /dev/null");
+
+	if (detach && daemonize(&daemonized))
+		die_errno(_("unable to detach"));
 	loop(fd, idle_in_seconds);
 
 	close(fd);
-- 
2.4.2.767.g62658d5-twtrsrc