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 18b9392334..44c80734b7 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 b1d7f8fb32..29356d25db 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 8c86974cbe..1e4a3d9c51 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 9c9977d892..8ce898a6b0 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 dec395deed..7d5c23edc4 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 3cd57dc385..021c3375c1 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 a18d505e56..1118b99e57 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 254ebb0fa6..618083bce0 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 */