INSTALL: explain info installation and dependencies.

diff --git a/config.c b/config.c
index f89a61191591c1242ba8fb3ac5b03330cdb1c06b..dd2de6e38e8d68d8622ad542e5c73cbcffeceeac 100644 (file)
--- a/config.c
+++ b/config.c
@@ -715,7 +715,7 @@ int git_config_set_multivar(const char* key, const char* value,
        int fd = -1, in_fd;
        int ret;
        char* config_filename;
-       char* lock_file;
+       struct lock_file *lock = NULL;
        const char* last_dot = strrchr(key, '.');
 
        config_filename = getenv(CONFIG_ENVIRONMENT);
@@ -725,7 +725,6 @@ int git_config_set_multivar(const char* key, const char* value,
                        config_filename  = git_path("config");
        }
        config_filename = xstrdup(config_filename);
-       lock_file = xstrdup(mkpath("%s.lock", config_filename));
 
        /*
         * Since "key" actually contains the section name and the real
@@ -770,11 +769,12 @@ int git_config_set_multivar(const char* key, const char* value,
        store.key[i] = 0;
 
        /*
-        * The lock_file serves a purpose in addition to locking: the new
+        * The lock serves a purpose in addition to locking: the new
         * contents of .git/config will be written into it.
         */
-       fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
-       if (fd < 0 || adjust_shared_perm(lock_file)) {
+       lock = xcalloc(sizeof(struct lock_file), 1);
+       fd = hold_lock_file_for_update(lock, config_filename, 0);
+       if (fd < 0) {
                fprintf(stderr, "could not lock config file\n");
                free(store.key);
                ret = -1;
@@ -914,25 +914,31 @@ int git_config_set_multivar(const char* key, const char* value,
                                goto write_err_out;
 
                munmap(contents, contents_sz);
-               unlink(config_filename);
        }
 
-       if (rename(lock_file, config_filename) < 0) {
-               fprintf(stderr, "Could not rename the lock file?\n");
+       if (close(fd) || commit_lock_file(lock) < 0) {
+               fprintf(stderr, "Cannot commit config file!\n");
                ret = 4;
                goto out_free;
        }
 
+       /* fd is closed, so don't try to close it below. */
+       fd = -1;
+       /*
+        * lock is committed, so don't try to roll it back below.
+        * NOTE: Since lockfile.c keeps a linked list of all created
+        * lock_file structures, it isn't safe to free(lock).  It's
+        * better to just leave it hanging around.
+        */
+       lock = NULL;
        ret = 0;
 
 out_free:
        if (0 <= fd)
                close(fd);
+       if (lock)
+               rollback_lock_file(lock);
        free(config_filename);
-       if (lock_file) {
-               unlink(lock_file);
-               free(lock_file);
-       }
        return ret;
 
 write_err_out: