dvd-sector-copy.c (recovery_read_sectors): Cross-check POS and OFF.

diff --git a/dvd-sector-copy.c b/dvd-sector-copy.c
index abab0b3..ef099b7 100644 (file)
--- a/dvd-sector-copy.c
+++ b/dvd-sector-copy.c
@@ -457,6 +457,7 @@ static ssize_t recovery_read_sectors(struct recoverybuf *r,
   ssize_t n;
 
   assert(off <= r->sz); assert(want <= r->sz - off);
+  assert(pos == r->pos + off);
   n = read_sectors(pos, r->buf + off*SECTORSZ, want);
   return (n);
 }