[PATCH v3 1/3] lockfile.c: remove PATH_MAX limitation (except in resolve_symlink)

[Nguyễn Thái Ngọc Duy]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclo...@gmail.com>
---
 cache.h    |  2 +-
 lockfile.c | 56 ++++++++++++++++++++++++++++++++------------------------
 2 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/cache.h b/cache.h
index cc46be4..0d8dce7 100644
--- a/cache.h
+++ b/cache.h
@@ -539,7 +539,7 @@ struct lock_file {
        int fd;
        pid_t owner;
        char on_list;
-       char filename[PATH_MAX];
+       char *filename;
 };
 #define LOCK_DIE_ON_ERROR 1
 #define LOCK_NODEREF 2
diff --git a/lockfile.c b/lockfile.c
index 8fbcb6a..968b28f 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -7,13 +7,19 @@
 static struct lock_file *lock_file_list;
 static const char *alternate_index_output;
 
+static void clear_filename(struct lock_file *lk)
+{
+       free(lk->filename);
+       lk->filename = NULL;
+}
+
 static void remove_lock_file(void)
 {
        pid_t me = getpid();
 
        while (lock_file_list) {
                if (lock_file_list->owner == me &&
-                   lock_file_list->filename[0]) {
+                   lock_file_list->filename) {
                        if (lock_file_list->fd >= 0)
                                close(lock_file_list->fd);
                        unlink_or_warn(lock_file_list->filename);
@@ -77,10 +83,16 @@ static char *last_path_elm(char *p)
  * Always returns p.
  */
 
-static char *resolve_symlink(char *p, size_t s)
+static char *resolve_symlink(const char *in)
 {
+       static char p[PATH_MAX];
+       size_t s = sizeof(p);
        int depth = MAXDEPTH;
 
+       if (strlen(in) >= sizeof(p))
+               return NULL;
+       strcpy(p, in);
+
        while (depth--) {
                char link[PATH_MAX];
                int link_len = readlink(p, link, sizeof(link));
@@ -124,17 +136,12 @@ static char *resolve_symlink(char *p, size_t s)
 
 static int lock_file(struct lock_file *lk, const char *path, int flags)
 {
-       /*
-        * subtract 5 from size to make sure there's room for adding
-        * ".lock" for the lock file name
-        */
-       static const size_t max_path_len = sizeof(lk->filename) - 5;
-
-       if (strlen(path) >= max_path_len)
+       int len;
+       if (!(flags & LOCK_NODEREF) && !(path = resolve_symlink(path)))
                return -1;
+       len = strlen(path) + 5; /* .lock */
+       lk->filename = xmallocz(len);
        strcpy(lk->filename, path);
-       if (!(flags & LOCK_NODEREF))
-               resolve_symlink(lk->filename, max_path_len);
        strcat(lk->filename, ".lock");
        lk->fd = open(lk->filename, O_RDWR | O_CREAT | O_EXCL, 0666);
        if (0 <= lk->fd) {
@@ -153,7 +160,7 @@ static int lock_file(struct lock_file *lk, const char 
*path, int flags)
                                     lk->filename);
        }
        else
-               lk->filename[0] = 0;
+               clear_filename(lk);
        return lk->fd;
 }
 
@@ -231,16 +238,17 @@ int close_lock_file(struct lock_file *lk)
 
 int commit_lock_file(struct lock_file *lk)
 {
-       char result_file[PATH_MAX];
-       size_t i;
-       if (lk->fd >= 0 && close_lock_file(lk))
+       char *result_file;
+       if ((lk->fd >= 0 && close_lock_file(lk)) || !lk->filename)
                return -1;
-       strcpy(result_file, lk->filename);
-       i = strlen(result_file) - 5; /* .lock */
-       result_file[i] = 0;
-       if (rename(lk->filename, result_file))
+       result_file = xmemdupz(lk->filename,
+                              strlen(lk->filename) - 5 /* .lock */);
+       if (rename(lk->filename, result_file)) {
+               free(result_file);
                return -1;
-       lk->filename[0] = 0;
+       }
+       free(result_file);
+       clear_filename(lk);
        return 0;
 }
 
@@ -260,11 +268,11 @@ void set_alternate_index_output(const char *name)
 int commit_locked_index(struct lock_file *lk)
 {
        if (alternate_index_output) {
-               if (lk->fd >= 0 && close_lock_file(lk))
+               if ((lk->fd >= 0 && close_lock_file(lk)) || !lk->filename)
                        return -1;
                if (rename(lk->filename, alternate_index_output))
                        return -1;
-               lk->filename[0] = 0;
+               clear_filename(lk);
                return 0;
        }
        else
@@ -273,10 +281,10 @@ int commit_locked_index(struct lock_file *lk)
 
 void rollback_lock_file(struct lock_file *lk)
 {
-       if (lk->filename[0]) {
+       if (lk->filename) {
                if (lk->fd >= 0)
                        close(lk->fd);
                unlink_or_warn(lk->filename);
        }
-       lk->filename[0] = 0;
+       clear_filename(lk);
 }
-- 
2.1.0.rc0.78.gc0d8480

--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html