Changeset 14147

Timestamp:

Jul 27, 2013, 4:18:12 PM (10 years ago)

Author:

jordan

Message:

(trunk, libt) #4147 'bad file descriptor': in cached_file_open(), ensure the file is always opened with writable permissions if we need to call ftruncate() to resize it. Large credit to karamanolev for tracking this down with strace.

File:

• trunk/libtransmission/fdlimit.c (modified) (3 diffs)

trunk/libtransmission/fdlimit.c

@@ -336 +336 @@
   int flags;
   struct stat sb;
-  bool alreadyExisted;
+  bool already_existed;
+  bool resize_needed;
 
   /* create subfolders, if any */
@@ -352 +353 @@
     }
 
-  alreadyExisted = !stat (filename, &sb) && S_ISREG (sb.st_mode);
-
-  if (writable && !alreadyExisted && (allocation == TR_PREALLOCATE_FULL))
+  already_existed = !stat (filename, &sb) && S_ISREG (sb.st_mode);
+
+  if (writable && !already_existed && (allocation == TR_PREALLOCATE_FULL))
     if (preallocate_file_full (filename, file_size))
       tr_logAddDebug ("Preallocated file \"%s\"", filename);
+
+  /* we can't resize the file w/o write permissions */
+  resize_needed = already_existed && (file_size < (uint64_t)sb.st_size);
+  writable |= resize_needed;
 
   /* open the file */
@@ -376 +381 @@
    * https://bugs.launchpad.net/ubuntu/+source/transmission/+bug/318249
    */
-  if (alreadyExisted && (file_size < (uint64_t)sb.st_size))
-    {
-      if (ftruncate (o->fd, file_size) == -1)
-        {
-          const int err = errno;
-          tr_logAddError (_("Couldn't truncate \"%1$s\": %2$s"), filename, tr_strerror (err));
-          return err;
-        }
-    }
-
-  if (writable && !alreadyExisted && (allocation == TR_PREALLOCATE_SPARSE))
+  if (resize_needed && (ftruncate (o->fd, file_size) == -1))
+    {
+      const int err = errno;
+      tr_logAddError (_("Couldn't truncate \"%1$s\": %2$s"), filename, tr_strerror (err));
+      return err;
+    }
+
+  if (writable && !already_existed && (allocation == TR_PREALLOCATE_SPARSE))
     preallocate_file_sparse (o->fd, file_size);