refactor signal handling for cleanup functions

The current code is very inconsistent about which signals
are caught for doing cleanup of temporary files and lock
files. Some callsites checked only SIGINT, while others
checked a variety of death-dealing signals.

This patch factors out those signals to a single function,
and then calls it everywhere. For some sites, that means
this is a simple clean up. For others, it is an improvement
in that they will now properly clean themselves up after a
larger variety of signals.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

8 files changed, 17 insertions, 13 deletions

diff --git a/builtin-clone.c b/builtin-clone.c
index 18b939233..44c80734b 100644
--- a/builtin-clone.c
+++ b/builtin-clone.c
@@ -439,7 +439,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	}
 	junk_git_dir = git_dir;
 	atexit(remove_junk);
-	sigchain_push(SIGINT, remove_junk_on_signal);
+	sigchain_push_common(remove_junk_on_signal);
 
 	setenv(CONFIG_ENVIRONMENT, xstrdup(mkpath("%s/config", git_dir)), 1);
 
diff --git a/builtin-fetch--tool.c b/builtin-fetch--tool.c
index b1d7f8fb3..29356d25d 100644
--- a/builtin-fetch--tool.c
+++ b/builtin-fetch--tool.c
@@ -246,7 +246,7 @@ static int fetch_native_store(FILE *fp,
 	char buffer[1024];
 	int err = 0;
 
-	sigchain_push(SIGINT, remove_keep_on_signal);
+	sigchain_push_common(remove_keep_on_signal);
 	atexit(remove_keep);
 
 	while (fgets(buffer, sizeof(buffer), stdin)) {
diff --git a/builtin-fetch.c b/builtin-fetch.c
index 8c86974cb..1e4a3d9c5 100644
--- a/builtin-fetch.c
+++ b/builtin-fetch.c
@@ -673,7 +673,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		ref_nr = j;
 	}
 
-	sigchain_push(SIGINT, unlock_pack_on_signal);
+	sigchain_push_common(unlock_pack_on_signal);
 	atexit(unlock_pack);
 	exit_code = do_fetch(transport,
 			parse_fetch_refspec(ref_nr, refs), ref_nr);
diff --git a/diff.c b/diff.c
index 9c9977d89..8ce898a6b 100644
--- a/diff.c
+++ b/diff.c
@@ -1903,7 +1903,7 @@ static struct diff_tempfile *prepare_temp_file(const char *name,
 
 	if (!remove_tempfile_installed) {
 		atexit(remove_tempfile);
-		sigchain_push(SIGINT, remove_tempfile_on_signal);
+		sigchain_push_common(remove_tempfile_on_signal);
 		remove_tempfile_installed = 1;
 	}
 
diff --git a/http-push.c b/http-push.c
index dec395dee..7d5c23edc 100644
--- a/http-push.c
+++ b/http-push.c
@@ -2262,10 +2262,7 @@ int main(int argc, char **argv)
 		goto cleanup;
 	}
 
-	sigchain_push(SIGINT, remove_locks_on_signal);
-	sigchain_push(SIGHUP, remove_locks_on_signal);
-	sigchain_push(SIGQUIT, remove_locks_on_signal);
-	sigchain_push(SIGTERM, remove_locks_on_signal);
+	sigchain_push_common(remove_locks_on_signal);
 
 	/* Check whether the remote has server info files */
 	remote->can_update_info_refs = 0;
diff --git a/lockfile.c b/lockfile.c
index 3cd57dc38..021c3375c 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -137,11 +137,7 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
 	lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
 	if (0 <= lk->fd) {
 		if (!lock_file_list) {
-			sigchain_push(SIGINT, remove_lock_file_on_signal);
-			sigchain_push(SIGHUP, remove_lock_file_on_signal);
-			sigchain_push(SIGTERM, remove_lock_file_on_signal);
-			sigchain_push(SIGQUIT, remove_lock_file_on_signal);
-			sigchain_push(SIGPIPE, remove_lock_file_on_signal);
+			sigchain_push_common(remove_lock_file_on_signal);
 			atexit(remove_lock_file);
 		}
 		lk->owner = getpid();
diff --git a/sigchain.c b/sigchain.c
index a18d505e5..1118b99e5 100644
--- a/sigchain.c
+++ b/sigchain.c
@@ -41,3 +41,12 @@ int sigchain_pop(int sig)
 	s->n--;
 	return 0;
 }
+
+void sigchain_push_common(sigchain_fun f)
+{
+	sigchain_push(SIGINT, f);
+	sigchain_push(SIGHUP, f);
+	sigchain_push(SIGTERM, f);
+	sigchain_push(SIGQUIT, f);
+	sigchain_push(SIGPIPE, f);
+}
diff --git a/sigchain.h b/sigchain.h
index 254ebb0fa..618083bce 100644
--- a/sigchain.h
+++ b/sigchain.h
@@ -6,4 +6,6 @@ typedef void (*sigchain_fun)(int);
 int sigchain_push(int sig, sigchain_fun f);
 int sigchain_pop(int sig);
 
+void sigchain_push_common(sigchain_fun f);
+
 #endif /* SIGCHAIN_H */