1 files changed, 37 insertions, 10 deletions

diff --git a/lockfile.c b/lockfile.c
index 6d75608693..b0d74cddde 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -2,6 +2,7 @@
  * Copyright (c) 2005, Junio C Hamano
  */
 #include "cache.h"
+#include "sigchain.h"
 
 static struct lock_file *lock_file_list;
 static const char *alternate_index_output;
@@ -15,7 +16,7 @@ static void remove_lock_file(void)
 		    lock_file_list->filename[0]) {
 			if (lock_file_list->fd >= 0)
 				close(lock_file_list->fd);
-			unlink(lock_file_list->filename);
+			unlink_or_warn(lock_file_list->filename);
 		}
 		lock_file_list = lock_file_list->next;
 	}
@@ -24,7 +25,7 @@ static void remove_lock_file(void)
 static void remove_lock_file_on_signal(int signo)
 {
 	remove_lock_file();
-	signal(signo, SIG_DFL);
+	sigchain_pop(signo);
 	raise(signo);
 }
 
@@ -108,7 +109,7 @@ static char *resolve_symlink(char *p, size_t s)
 			 * link is a relative path, so I must replace the
 			 * last element of p with it.
 			 */
-			char *r = (char*)last_path_elm(p);
+			char *r = (char *)last_path_elm(p);
 			if (r - p + link_len < s)
 				strcpy(r, link);
 			else {
@@ -136,10 +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) {
-			signal(SIGINT, remove_lock_file_on_signal);
-			signal(SIGHUP, remove_lock_file_on_signal);
-			signal(SIGTERM, remove_lock_file_on_signal);
-			signal(SIGQUIT, remove_lock_file_on_signal);
+			sigchain_push_common(remove_lock_file_on_signal);
 			atexit(remove_lock_file);
 		}
 		lk->owner = getpid();
@@ -157,11 +155,40 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
 	return lk->fd;
 }
 
+static char *unable_to_lock_message(const char *path, int err)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	if (err == EEXIST) {
+		strbuf_addf(&buf, "Unable to create '%s.lock': %s.\n\n"
+		    "If no other git process is currently running, this probably means a\n"
+		    "git process crashed in this repository earlier. Make sure no other git\n"
+		    "process is running and remove the file manually to continue.",
+			    make_nonrelative_path(path), strerror(err));
+	} else
+		strbuf_addf(&buf, "Unable to create '%s.lock': %s",
+			    make_nonrelative_path(path), strerror(err));
+	return strbuf_detach(&buf, NULL);
+}
+
+int unable_to_lock_error(const char *path, int err)
+{
+	char *msg = unable_to_lock_message(path, err);
+	error("%s", msg);
+	free(msg);
+	return -1;
+}
+
+NORETURN void unable_to_lock_index_die(const char *path, int err)
+{
+	die("%s", unable_to_lock_message(path, err));
+}
+
 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
 {
 	int fd = lock_file(lk, path, flags);
 	if (fd < 0 && (flags & LOCK_DIE_ON_ERROR))
-		die("unable to create '%s.lock': %s", path, strerror(errno));
+		unable_to_lock_index_die(path, errno);
 	return fd;
 }
 
@@ -172,7 +199,7 @@ int hold_lock_file_for_append(struct lock_file *lk, const char *path, int flags)
 	fd = lock_file(lk, path, flags);
 	if (fd < 0) {
 		if (flags & LOCK_DIE_ON_ERROR)
-			die("unable to create '%s.lock': %s", path, strerror(errno));
+			unable_to_lock_index_die(path, errno);
 		return fd;
 	}
 
@@ -247,7 +274,7 @@ void rollback_lock_file(struct lock_file *lk)
 	if (lk->filename[0]) {
 		if (lk->fd >= 0)
 			close(lk->fd);
-		unlink(lk->filename);
+		unlink_or_warn(lk->filename);
 	}
 	lk->filename[0] = 0;
 }