1 files changed, 57 insertions, 0 deletions
diff --git a/lockfile.c b/lockfile.c
new file mode 100644
index 0000000000..9bc60837aa
--- /dev/null
+++ b/lockfile.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2005, Junio C Hamano
+ */
+#include <signal.h>
+#include "cache.h"
+
+static struct lock_file *lock_file_list;
+
+static void remove_lock_file(void)
+{
+	while (lock_file_list) {
+		if (lock_file_list->filename[0])
+			unlink(lock_file_list->filename);
+		lock_file_list = lock_file_list->next;
+	}
+}
+
+static void remove_lock_file_on_signal(int signo)
+{
+	remove_lock_file();
+	signal(SIGINT, SIG_DFL);
+	raise(signo);
+}
+
+int hold_lock_file_for_update(struct lock_file *lk, const char *path)
+{
+	int fd;
+	sprintf(lk->filename, "%s.lock", path);
+	fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
+	if (fd >=0 && !lk->next) {
+		lk->next = lock_file_list;
+		lock_file_list = lk;
+		signal(SIGINT, remove_lock_file_on_signal);
+		atexit(remove_lock_file);
+	}
+	return fd;
+}
+
+int commit_lock_file(struct lock_file *lk)
+{
+	char result_file[PATH_MAX];
+	int i;
+	strcpy(result_file, lk->filename);
+	i = strlen(result_file) - 5; /* .lock */
+	result_file[i] = 0;
+	i = rename(lk->filename, result_file);
+	lk->filename[0] = 0;
+	return i;
+}
+
+void rollback_lock_file(struct lock_file *lk)
+{
+	if (lk->filename[0])
+		unlink(lk->filename);
+	lk->filename[0] = 0;
+}
+