From: Johannes Sixt <j6t@xxxxxxxx>
On POSIX, rename() can replace files that are not writable. On Windows,
however, read-only files cannot be replaced without additional efforts:
We have to make the destination writable first.
Since the situations where the destination is read-only are rare, we do not
make the destination writable on every invocation, but only if the first
try to rename a file failed with an "access denied" error.
Signed-off-by: Johannes Sixt <j6t@xxxxxxxx>
---
Johannes Sixt schrieb:
> Nicolas Pitre schrieb:
>> On Wed, 19 Nov 2008, Johannes Sixt wrote:
>>> The unusual case is where you do this:
>>>
>>> $ git rev-list -10 HEAD | git pack-objects foobar
>>>
>>> twice in a row: In this case the second invocation fails on Windows
>>> because the destination pack file already exists *and* is open. But not
>>> even git-repack does this even if it is called twice. OTOH, the test case
>>> *does* exactly this.
>> OK.... Well, despite my earlier assertion, I think the above should be a
>> valid operation.
Would you please clarify which operation you exactly mean? As is written
above, or with .git/objects/pack/foobar instead like in the test case?
>> I'm looking at it now. I'm therefore revoking my earlier ACK as well
>> (better keep that test case alive).
>
> Hold on a moment: When I tested the above sequence, I was fooled by a flaw
> in mingw_rename() (it doesn't replace read-only files). With that fixed...
Here is this fix.
-- Hannes
compat/mingw.c | 15 ++++++++++++---
1 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c
index b534a8a..3dbe6a7 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -819,6 +819,8 @@ int mingw_connect(int sockfd, struct sockaddr *sa, size_t sz)
#undef rename
int mingw_rename(const char *pold, const char *pnew)
{
+ DWORD attrs;
+
/*
* Try native rename() first to get errno right.
* It is based on MoveFile(), which cannot overwrite existing files.
@@ -830,12 +832,19 @@ int mingw_rename(const char *pold, const char *pnew)
if (MoveFileEx(pold, pnew, MOVEFILE_REPLACE_EXISTING))
return 0;
/* TODO: translate more errors */
- if (GetLastError() == ERROR_ACCESS_DENIED) {
- DWORD attrs = GetFileAttributes(pnew);
- if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
+ if (GetLastError() == ERROR_ACCESS_DENIED &&
+ (attrs = GetFileAttributes(pnew)) != INVALID_FILE_ATTRIBUTES) {
+ if (attrs & FILE_ATTRIBUTE_DIRECTORY) {
errno = EISDIR;
return -1;
}
+ if ((attrs & FILE_ATTRIBUTE_READONLY) &&
+ SetFileAttributes(pnew, attrs & ~FILE_ATTRIBUTE_READONLY)) {
+ if (MoveFileEx(pold, pnew, MOVEFILE_REPLACE_EXISTING))
+ return 0;
+ /* revert file attributes on failure */
+ SetFileAttributes(pnew, attrs);
+ }
}
errno = EACCES;
return -1;
--
1.6.0.4.1694.g07ac
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