# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1666299821 -7200
# Node ID 07dc5a5e97f8f1262c71c009bd0fe8ce3a3ef193
# Parent  fc87683fd17298a08822f68925d64b33efd54d0d
Handle possible error conditions when seeking to blocks.

diff -r fc87683fd172 -r 07dc5a5e97f8 libext2fs_blockserver/lib/src/blockserver_io.c
--- a/libext2fs_blockserver/lib/src/blockserver_io.c	Sun Oct 02 00:39:35 2022 +0200
+++ b/libext2fs_blockserver/lib/src/blockserver_io.c	Thu Oct 20 23:03:41 2022 +0200
@@ -205,13 +205,20 @@
 
   /* Perform the read at the given location. */
 
-  client_seek(data->file, block * channel->block_size, SEEK_SET);
-  read = client_read(data->file, buf, to_read);
+  if (client_seek(data->file, block * channel->block_size, SEEK_SET) != block * channel->block_size)
+  {
+    read = 0;
+    retval = EXT2_ET_LLSEEK_FAILED;
+  }
+  else
+  {
+    read = client_read(data->file, buf, to_read);
 
-  /* Check for a short read. */
+    /* Check for a short read. */
 
-  if (read < to_read)
-    retval = EXT2_ET_SHORT_READ;
+    if (read < to_read)
+      retval = EXT2_ET_SHORT_READ;
+  }
 
   /* Handle read errors generally. */
 
@@ -238,13 +245,20 @@
 
   /* Perform the write at the given location. */
 
-  client_seek(data->file, block * channel->block_size, SEEK_SET);
-  written = client_write(data->file, buf, to_write);
+  if (client_seek(data->file, block * channel->block_size, SEEK_SET) != block * channel->block_size)
+  {
+    retval = EXT2_ET_LLSEEK_FAILED;
+    written = 0;
+  }
+  else
+  {
+    written = client_write(data->file, buf, to_write);
 
-  /* Check for a short write. */
+    /* Check for a short write. */
 
-  if (written < to_write)
-    retval = EXT2_ET_SHORT_WRITE;
+    if (written < to_write)
+      retval = EXT2_ET_SHORT_WRITE;
+  }
 
   /* Handle write errors generally. */