X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;f=ucw%2Fpartmap.c;h=a823d3d157fa29d1355db9c68ad5bd040b83f5c6;hb=31316f76dd68a03b803f51931d6e1fff2c60c5d1;hp=962b04bfefa00096371bec672894850a61ab906c;hpb=e938d9e3bf5c98b502178ee26d81a410890fb725;p=libucw.git

diff --git a/ucw/partmap.c b/ucw/partmap.c
index 962b04bf..a823d3d1 100644
--- a/ucw/partmap.c
+++ b/ucw/partmap.c
@@ -2,7 +2,7 @@
  *	UCW Library -- Mapping of File Parts
  *
  *	(c) 2003--2006 Martin Mares <mj@ucw.cz>
- *	(c) 2003--2005 Robert Spalek <robert@ucw.cz>
+ *	(c) 2003--2009 Robert Spalek <robert@ucw.cz>
  *
  *	This software may be freely distributed and used according to the terms
  *	of the GNU Lesser General Public License.
@@ -69,13 +69,18 @@ partmap_load(struct partmap *p, ucw_off_t start, uns size)
   ucw_off_t end = start + size;
   ucw_off_t win_start = start/CPU_PAGE_SIZE * CPU_PAGE_SIZE;
   size_t win_len = PARTMAP_WINDOW;
-  if ((ucw_off_t) (win_start+win_len) > p->file_size)
+  if (win_len > (size_t) (p->file_size - win_start))
     win_len = ALIGN_TO(p->file_size - win_start, CPU_PAGE_SIZE);
   if ((ucw_off_t) (win_start+win_len) < end)
     die("partmap_map: Window is too small for mapping %d bytes", size);
-  p->start_map = ucw_mmap(NULL, win_len, p->writeable ? (PROT_READ | PROT_WRITE) : PROT_READ, MAP_SHARED, p->fd, win_start);
-  if (p->start_map == MAP_FAILED)
-    die("mmap failed at position %lld: %m", (long long)win_start);
+  if (win_len)
+    {
+      p->start_map = ucw_mmap(NULL, win_len, p->writeable ? (PROT_READ | PROT_WRITE) : PROT_READ, MAP_SHARED, p->fd, win_start);
+      if (p->start_map == MAP_FAILED)
+	die("mmap failed at position %lld: %m", (long long)win_start);
+    }
+  else
+    p->start_map = NULL;
   p->start_off = win_start;
   p->end_off = win_start+win_len;
   madvise(p->start_map, win_len, MADV_SEQUENTIAL);