Anonymous committed 0a3881d

Seek back to current filepos when mmap()ing with NO_MMAP

"git-index-pack --fix-thin" relies on mmap() not changing the current
file position (otherwise the pack will be corrupted when writing the
final SHA1). Meet that expectation.

Signed-off-by: Johannes Schindelin <>
Signed-off-by: Junio C Hamano <>

Comments (0)

Files changed (1)

 void *gitfakemmap(void *start, size_t length, int prot , int flags, int fd, off_t offset)
 	int n = 0;
+	off_t current_offset = lseek(fd, 0, SEEK_CUR);
 	if (start != NULL || !(flags & MAP_PRIVATE))
 		die("Invalid usage of gitfakemmap.");
 		n += count;
+	if (current_offset != lseek(fd, current_offset, SEEK_SET)) {
+		errno = EINVAL;
+		return MAP_FAILED;
+	}
 	return start;
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