[PATCH] fix hang in git fetch if pointed at a 0 length bundle

git-repo if interupted at the exact wrong time will generate zero
length bundles- literal empty files.  git-repo is wrong here, but
git fetch shouldn't effectively spin loop if pointed at a zero
length bundle.

Signed-off-by: Brian Harring <redacted>
---
 bundle.c          |    2 +-
 t/t5704-bundle.sh |   10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/bundle.c b/bundle.c
index 4742f27..ac9cc20 100644
--- a/bundle.c
+++ b/bundle.c

@@ -31,7 +31,7 @@ static int strbuf_readline_fd(struct strbuf *sb, int fd)
 	while (1) {
 		char ch;
 		ssize_t len = xread(fd, &ch, 1);
-		if (len < 0)
+		if (len <= 0)
 			return -1;
 		strbuf_addch(sb, ch);
 		if (ch == '\n')

diff --git a/t/t5704-bundle.sh b/t/t5704-bundle.sh
index 728ccd8..75ce5b8 100755
--- a/t/t5704-bundle.sh
+++ b/t/t5704-bundle.sh

@@ -53,4 +53,14 @@ test_expect_failure 'bundle --stdin <rev-list options>' '
 
 '
 
+test_expect_success 'die if bundle file is empty' '
+
+   echo -n > empty-bundle
+   timeout 5 git fetch empty-bundle
+   ret=$?
+   [ $ret == 128 ] && return 0
+   return $ret
+
+'
+
 test_done

-- 
1.7.8.2

Am 03.01.2012 02:13, schrieb Brian Harring:

git-repo if interupted at the exact wrong time will generate zero
length bundles- literal empty files.  git-repo is wrong here, but
git fetch shouldn't effectively spin loop if pointed at a zero
length bundle.

Adding a test case is very much appreciated.

+test_expect_success 'die if bundle file is empty' '

How about 'empty bundle file is rejected'?

+
+   echo -n > empty-bundle

'echo -n' is not portable; use simply

	>empty-bundle &&

(note the style: no blank after >). Also chain commands using &&.

+   timeout 5 git fetch empty-bundle

Yes, there was an infinite loop. But we do not specifically protect our
git invocations in the test suite against this sort of failure. Just write

	test_must_fail git fetch empty-bundle

and end the test case here.

+   ret=$?
+   [ $ret == 128 ] && return 0
+   return $ret
+
+'

Furthermore, indentation should be one tabstop, not blanks.

-- Hannes

On Tue, Jan 3, 2012 at 8:13 AM, Brian Harring [off-list ref] wrote:

I think it should return 0 when len == 0 because strictly speaking eof
is not a fault. It's not really important though because the two
callers in this file work fine either way.

FWIW I went through all xread call sites. All seem to handle return
value <= 0 correctly.
-- 
Duy

git-repo if interupted at the exact wrong time will generate zero
length bundles- literal empty files.  git-repo is wrong here, but
git fetch shouldn't effectively spin loop if pointed at a zero
length bundle.

Signed-off-by: Brian Harring <redacted>
---
 bundle.c          |    4 ++--
 t/t5704-bundle.sh |    6 ++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/bundle.c b/bundle.c
index 4742f27..b8acf3c 100644
--- a/bundle.c
+++ b/bundle.c

@@ -31,8 +31,8 @@ static int strbuf_readline_fd(struct strbuf *sb, int fd)
 	while (1) {
 		char ch;
 		ssize_t len = xread(fd, &ch, 1);
-		if (len < 0)
-			return -1;
+		if (len <= 0)
+			return len;
 		strbuf_addch(sb, ch);
 		if (ch == '\n')
 			break;

diff --git a/t/t5704-bundle.sh b/t/t5704-bundle.sh
index 728ccd8..4ae127d 100755
--- a/t/t5704-bundle.sh
+++ b/t/t5704-bundle.sh

@@ -53,4 +53,10 @@ test_expect_failure 'bundle --stdin <rev-list options>' '
 
 '
 
+test_expect_success 'empty bundle file is rejected' '
+
+    >empty-bundle && test_must_fail git fetch empty-bundle
+
+'
+
 test_done

-- 
1.7.8.2