cache.c: make all io-related functions return errno on error

We'll need proper return-values from these functions to make the cache
behave correctly (which includes giving proper error messages).

Noticed-by: Jim Meyering <jim@meyering.net>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

diff --git a/cache.c b/cache.c
index add647ef4661648f922ed246141c216e80b2150f..68472029e2e314f7d0f11f0f07c37fb6d0565deb 100644 (file)
--- a/cache.c
+++ b/cache.c
@@ -66,12 +66,16 @@ static int open_slot(struct cache_slot *slot)
 }
 
 /* Close the active cache slot */
-static void close_slot(struct cache_slot *slot)
+static int close_slot(struct cache_slot *slot)
 {
+       int err = 0;
        if (slot->cache_fd > 0) {
-               close(slot->cache_fd);
-               slot->cache_fd = -1;
+               if (close(slot->cache_fd))
+                       err = errno;
+               else
+                       slot->cache_fd = -1;
        }
+       return err;
 }
 
 /* Print the content of the active cache slot (but skip the key). */
@@ -116,12 +120,16 @@ static int is_modified(struct cache_slot *slot)
 }
 
 /* Close an open lockfile */
-static void close_lock(struct cache_slot *slot)
+static int close_lock(struct cache_slot *slot)
 {
+       int err = 0;
        if (slot->lock_fd > 0) {
-               close(slot->lock_fd);
-               slot->lock_fd = -1;
+               if (close(slot->lock_fd))
+                       err = errno;
+               else
+                       slot->lock_fd = -1;
        }
+       return err;
 }
 
 /* Create a lockfile used to store the generated content for a cache
@@ -134,7 +142,8 @@ static int lock_slot(struct cache_slot *slot)
                             S_IRUSR|S_IWUSR);
        if (slot->lock_fd == -1)
                return errno;
-       write(slot->lock_fd, slot->key, slot->keylen + 1);
+       if (write(slot->lock_fd, slot->key, slot->keylen + 1) < 0)
+               return errno;
        return 0;
 }
 
@@ -150,7 +159,11 @@ static int unlock_slot(struct cache_slot *slot, int replace_old_slot)
                err = rename(slot->lock_name, slot->cache_name);
        else
                err = unlink(slot->lock_name);
-       return err;
+
+       if (err)
+               return errno;
+
+       return 0;
 }
 
 /* Generate the content for the current cache slot by redirecting
@@ -177,7 +190,9 @@ static int fill_slot(struct cache_slot *slot)
                return errno;
 
        /* Close the temporary filedescriptor */
-       close(tmp);
+       if (close(tmp))
+               return errno;
+
        return 0;
 }