From: "Torsten Bögershausen" <tboegi@web.de>
To: Steffen Prohaska <prohaska@zib.de>
Cc: Junio C Hamano <gitster@pobox.com>, git@vger.kernel.org
Subject: Re: [PATCH] xread(): Fix read error when filtering >= 2GB on Mac OS X
Date: Sat, 17 Aug 2013 17:56:16 +0200 [thread overview]
Message-ID: <520F9D20.7000008@web.de> (raw)
In-Reply-To: <1376743205-12618-1-git-send-email-prohaska@zib.de>
On 2013-08-17 14.40, Steffen Prohaska wrote:
> Previously, filtering more than 2GB through an external filter (see
> test) failed on Mac OS X 10.8.4 (12E55) with:
>
> error: read from external filter cat failed
> error: cannot feed the input to external filter cat
> error: cat died of signal 13
> error: external filter cat failed 141
> error: external filter cat failed
>
> The reason is that read() immediately returns with EINVAL if len >= 2GB.
> I haven't found any information under which specific conditions this
> occurs. My suspicion is that it happens when reading from a pipe, while
> reading from a standard file should always be fine. I haven't tested
> any other version of Mac OS X, though I'd expect that other versions are
> affected as well.
>
> The problem is fixed by always reading less than 2GB in xread().
> xread() doesn't guarantee to read all the requested data at once, and
> callers are expected to gracefully handle partial reads. Slicing large
> reads into 2GB pieces should not hurt practical performance.
>
> Signed-off-by: Steffen Prohaska <prohaska@zib.de>
> ---
> t/t0021-conversion.sh | 9 +++++++++
> wrapper.c | 8 ++++++++
> 2 files changed, 17 insertions(+)
>
> diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh
> index e50f0f7..aec1253 100755
> --- a/t/t0021-conversion.sh
> +++ b/t/t0021-conversion.sh
> @@ -190,4 +190,13 @@ test_expect_success 'required filter clean failure' '
> test_must_fail git add test.fc
> '
>
> +test_expect_success 'filter large file' '
> + git config filter.largefile.smudge cat &&
> + git config filter.largefile.clean cat &&
> + dd if=/dev/zero of=2GB count=2097152 bs=1024 &&
> + echo "/2GB filter=largefile" >.gitattributes &&
> + git add 2GB 2>err &&
> + ! grep -q "error" err
> +'
> +
> test_done
> diff --git a/wrapper.c b/wrapper.c
> index 6a015de..2a2f496 100644
> --- a/wrapper.c
> +++ b/wrapper.c
> @@ -139,6 +139,14 @@ ssize_t xread(int fd, void *buf, size_t len)
> {
> ssize_t nr;
> while (1) {
> +#ifdef __APPLE__
> + const size_t twoGB = (1l << 31);
> + /* len >= 2GB immediately fails on Mac OS X with EINVAL when
> + * reading from pipe. */
> + if (len >= twoGB) {
> + len = twoGB - 1;
> + }
> +#endif
> nr = read(fd, buf, len);
> if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
> continue;
>
Thanks for the patch.
I think we can we can replace __APPLE__ define with a more generic one.
We had a similar patch for write() some time ago:
config.mak.uname
NEEDS_CLIPPED_WRITE = YesPlease
Makefile
ifdef NEEDS_CLIPPED_WRITE
BASIC_CFLAGS += -DNEEDS_CLIPPED_WRITE
COMPAT_OBJS += compat/clipped-write.o
endif
next prev parent reply other threads:[~2013-08-17 15:56 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-17 12:40 [PATCH] xread(): Fix read error when filtering >= 2GB on Mac OS X Steffen Prohaska
2013-08-17 15:27 ` John Keeping
2013-08-17 15:56 ` Torsten Bögershausen [this message]
2013-08-17 17:16 ` Johannes Sixt
2013-08-17 18:57 ` Jonathan Nieder
2013-08-17 20:25 ` Kyle J. McKay
2013-08-17 21:23 ` Jonathan Nieder
2013-08-19 6:38 ` [PATCH v2] compat: Fix read() of 2GB and more " Steffen Prohaska
2013-08-19 7:54 ` John Keeping
2013-08-19 8:20 ` Steffen Prohaska
2013-08-19 8:20 ` Johannes Sixt
2013-08-19 8:25 ` Stefan Beller
2013-08-19 8:40 ` Johannes Sixt
2013-08-19 8:28 ` Steffen Prohaska
2013-08-19 8:21 ` [PATCH v3] " Steffen Prohaska
2013-08-19 13:59 ` Eric Sunshine
2013-08-19 16:33 ` Junio C Hamano
2013-08-19 15:41 ` [PATCH v4] " Steffen Prohaska
2013-08-19 16:04 ` Linus Torvalds
2013-08-19 16:37 ` Steffen Prohaska
2013-08-19 17:24 ` Junio C Hamano
2013-08-19 17:16 ` Junio C Hamano
2013-08-19 17:28 ` Linus Torvalds
2013-08-19 21:56 ` Kyle J. McKay
2013-08-19 22:51 ` Linus Torvalds
2013-08-27 4:59 ` Junio C Hamano
2013-08-20 6:43 ` [PATCH v5 0/2] Fix IO of >=2GB on Mac OS X by limiting IO chunks Steffen Prohaska
2013-08-20 6:43 ` [PATCH v5 1/2] xread, xwrite: Limit size of IO, fixing IO of 2GB and more on Mac OS X Steffen Prohaska
2013-08-20 19:37 ` Junio C Hamano
2013-08-21 19:50 ` Torsten Bögershausen
2013-08-20 6:43 ` [PATCH v5 2/2] Revert "compate/clipped-write.c: large write(2) fails on Mac OS X/XNU" Steffen Prohaska
2013-08-21 13:46 ` [PATCH v6 0/2] Fix IO >= 2GB on Mac, fixed typo Steffen Prohaska
2013-08-21 13:46 ` [PATCH v5 1/2] xread, xwrite: Limit size of IO, fixing IO of 2GB and more on Mac OS X Steffen Prohaska
2013-08-21 13:46 ` [PATCH v5 2/2] Revert "compate/clipped-write.c: large write(2) fails on Mac OS X/XNU" Steffen Prohaska
2013-08-21 15:58 ` [PATCH v6 0/2] Fix IO >= 2GB on Mac, fixed typo Junio C Hamano
2013-08-19 8:27 ` [PATCH v2] compat: Fix read() of 2GB and more on Mac OS X Johannes Sixt
2013-08-19 14:41 ` Torsten Bögershausen
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