mergetools/meld: make usage of `--output` configurable and more robust

diff --git a/lockfile.c b/lockfile.c
index b7066143494bcfa3e629dd718daf8959af6c4b86..2564a7f5447b904585f629f0d1233c8a59483a40 100644 (file)
--- a/lockfile.c
+++ b/lockfile.c
@@ -120,7 +120,7 @@ static char *resolve_symlink(char *p, size_t s)
        return p;
 }
 
-
+/* Make sure errno contains a meaningful value on error */
 static int lock_file(struct lock_file *lk, const char *path, int flags)
 {
        /*
@@ -129,8 +129,10 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
         */
        static const size_t max_path_len = sizeof(lk->filename) - 5;
 
-       if (strlen(path) >= max_path_len)
+       if (strlen(path) >= max_path_len) {
+               errno = ENAMETOOLONG;
                return -1;
+       }
        strcpy(lk->filename, path);
        if (!(flags & LOCK_NODEREF))
                resolve_symlink(lk->filename, max_path_len);
@@ -147,44 +149,51 @@ static int lock_file(struct lock_file *lk, const char *path, int flags)
                        lock_file_list = lk;
                        lk->on_list = 1;
                }
-               if (adjust_shared_perm(lk->filename))
-                       return error("cannot fix permission bits on %s",
-                                    lk->filename);
+               if (adjust_shared_perm(lk->filename)) {
+                       int save_errno = errno;
+                       error("cannot fix permission bits on %s",
+                             lk->filename);
+                       errno = save_errno;
+                       return -1;
+               }
        }
        else
                lk->filename[0] = 0;
        return lk->fd;
 }
 
-static char *unable_to_lock_message(const char *path, int err)
+void unable_to_lock_message(const char *path, int err, struct strbuf *buf)
 {
-       struct strbuf buf = STRBUF_INIT;
-
        if (err == EEXIST) {
-               strbuf_addf(&buf, "Unable to create '%s.lock': %s.\n\n"
+               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.",
                            absolute_path(path), strerror(err));
        } else
-               strbuf_addf(&buf, "Unable to create '%s.lock': %s",
+               strbuf_addf(buf, "Unable to create '%s.lock': %s",
                            absolute_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);
+       struct strbuf buf = STRBUF_INIT;
+
+       unable_to_lock_message(path, err, &buf);
+       error("%s", buf.buf);
+       strbuf_release(&buf);
        return -1;
 }
 
 NORETURN void unable_to_lock_index_die(const char *path, int err)
 {
-       die("%s", unable_to_lock_message(path, err));
+       struct strbuf buf = STRBUF_INIT;
+
+       unable_to_lock_message(path, err, &buf);
+       die("%s", buf.buf);
 }
 
+/* This should return a meaningful errno on failure */
 int hold_lock_file_for_update(struct lock_file *lk, const char *path, int flags)
 {
        int fd = lock_file(lk, path, flags);