Changeset 730 for soft/giet_vm/giet_fat32

Timestamp:

Nov 21, 2015, 2:57:45 PM (9 years ago)

Author:

alain

Message:

Improve seek overflow checking.

File:

• soft/giet_vm/giet_fat32/fat32.c (modified) (3 diffs)

soft/giet_vm/giet_fat32/fat32.c

@@ -3198 +3198 @@
 /////////////////////////////////////////////////////////////////////////////////
 // Returns the number of bytes actually transfered on success.
-// Returns 0 if EOF is encountered (offset + count > file_size). 
 // Returns a negative value on error:
 //   GIET_FAT32_NOT_INITIALIZED,
@@ -3249 +3248 @@
     _spin_lock_acquire( &_fat.fat_lock );
     _atomic_or( &psched->context[ltid].slot[CTX_LOCKS_ID] , LOCKS_MASK_FAT ); 
-
            
     // get file inode pointer and offset
@@ -3255 +3253 @@
     unsigned int seek   = _fat.fd[fd_id].seek;
 
-    // check count & seek versus file size
-    if ( count + seek > inode->size && !inode->is_dir )
+    // check seek versus file size
+    if ( (seek >= inode->size) && !inode->is_dir )
     {
         _spin_lock_release( &_fat.fat_lock );
         _atomic_and( &psched->context[ltid].slot[CTX_LOCKS_ID] , ~LOCKS_MASK_FAT ); 
 
-        _printf("\n[FAT ERROR] _fat_read(): file too small"
-                " / seek = %x / count = %x / file_size = %x\n",
-                seek , count , inode->size );
-        return 0;
-    }
+        _printf("\n[FAT ERROR] _fat_read(): seek larger than file size"
+                " / seek = %x / file_size = %x\n",
+                seek , inode->size );
+        return GIET_FAT32_IO_ERROR;
+    }
+
+    // check and ajust count argument
+    if ( count > (inode->size - seek) ) count = inode->size - seek;
 
     // compute first_cluster_id and first_byte_to_move