From: Tom Clegg <tom@curoverse.com>
Date: Tue, 22 Sep 2015 16:01:25 +0000 (-0400)
Subject: 7329: Fix infinite loop in Compare when reading an empty file.
X-Git-Tag: 1.1.0~1349
X-Git-Url: https://git.arvados.org/arvados.git/commitdiff_plain/783a6278efb607b201df2781942a0b1c6a385929

7329: Fix infinite loop in Compare when reading an empty file.

refs #7329
---

diff --git a/services/keepstore/volume_unix.go b/services/keepstore/volume_unix.go
index afae2796bc..6c0f5c4e97 100644
--- a/services/keepstore/volume_unix.go
+++ b/services/keepstore/volume_unix.go
@@ -122,6 +122,13 @@ func (v *UnixVolume) Compare(loc string, expect []byte) error {
 	bufLen := 1 << 20
 	if int64(bufLen) > stat.Size() {
 		bufLen = int(stat.Size())
+		if bufLen < 1 {
+			// len(buf)==0 would prevent us from handling
+			// empty files the same way as non-empty
+			// files, because reading 0 bytes at a time
+			// never reaches EOF.
+			bufLen = 1
+		}
 	}
 	cmp := expect
 	buf := make([]byte, bufLen)