From mboxrd@z Thu Jan 1 00:00:00 1970 From: Junio C Hamano Subject: Re: write() _will_ fail on Mac OS X/XNU if nbytes > INT_MAX Date: Fri, 10 May 2013 16:05:02 -0700 Message-ID: <7va9o2zba9.fsf@alter.siamese.dyndns.org> References: <7v4nffpbct.fsf@alter.siamese.dyndns.org> <7vbo8j600q.fsf@alter.siamese.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org To: Filipe Cabecinhas X-From: git-owner@vger.kernel.org Sat May 11 01:05:15 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1UawNH-00058m-15 for gcvg-git-2@plane.gmane.org; Sat, 11 May 2013 01:05:15 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755095Ab3EJXFI (ORCPT ); Fri, 10 May 2013 19:05:08 -0400 Received: from b-pb-sasl-quonix.pobox.com ([208.72.237.35]:48288 "EHLO smtp.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754825Ab3EJXFH (ORCPT ); Fri, 10 May 2013 19:05:07 -0400 Received: from smtp.pobox.com (unknown [127.0.0.1]) by b-sasl-quonix.pobox.com (Postfix) with ESMTP id 757061E1C8; Fri, 10 May 2013 23:05:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=05emjP89KuAiw7gvx4OTOHTblxA=; b=sLAnHU PxvU5dDcnJKiXFNFPGnQqGy3C/Z+Gt1sSvgk4zpv8jJHZIoLxDw9iNRGkfzdny5l N0FMJZPruT2SoDFyvZUbYCuhXkoJtWH5KJjP02Fo9P2kweKSP1vcbHfZc97Q7hm3 2yf+i/Ie5zxg3gnMJSC3bfqDK9BfNolN7JsXI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=W0PKnoqi/xGGBBP0lUpzb9dpGPfR5r6X 5DI6A8n3sYXguIVcVMj2uPumYl59MkRSVoUs0yZSENdUlNUoU38vSk0d7TomdjQC x1PzByFBuR/LN8MsDGTvXwYm8+Jip2dzomI6V+vVUfzA4nMMjQzmgyhbgxdwgIM8 uU8YDw2Xu2I= Received: from b-pb-sasl-quonix.pobox.com (unknown [127.0.0.1]) by b-sasl-quonix.pobox.com (Postfix) with ESMTP id 6D2FC1E1C6; Fri, 10 May 2013 23:05:05 +0000 (UTC) Received: from pobox.com (unknown [50.152.208.16]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by b-sasl-quonix.pobox.com (Postfix) with ESMTPSA id A82AD1E1C5; Fri, 10 May 2013 23:05:04 +0000 (UTC) In-Reply-To: (Filipe Cabecinhas's message of "Fri, 10 May 2013 15:24:57 -0700") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) X-Pobox-Relay-ID: 0CFB6E20-B9C6-11E2-87DA-E56BAAC0D69C-77302942!b-pb-sasl-quonix.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Filipe Cabecinhas writes: > Due to a bug in the Darwin kernel, write() calls have a maximum size of > INT_MAX bytes. > > This patch introduces a new compat function: clipped_write > This function behaves the same as write() but will write, at most, INT_MAX > characters. > It may be necessary to include this function on Windows, too. > > Signed-off-by: Filipe Cabecinhas > --- Somehow your MUA seems to have lost _all_ tabs, not just in the new lines in your patch but also in the existing context lines. > diff --git a/Makefile b/Makefile > index 0f931a2..ccb8f3f 100644 > --- a/Makefile > +++ b/Makefile > @@ -1466,6 +1466,11 @@ ifndef NO_MSGFMT_EXTENDED_OPTIONS > MSGFMT += --check --statistics > endif > > +ifdef NEEDS_CLIPPED_WRITE > + BASIC_CFLAGS += -DNEEDS_CLIPPED_WRITE > + COMPAT_OBJS += compat/clipped-write.o > +endif > + > ... Here is what I resurrected and queued. I _think_ I did not make any silly mistake while transcribing from your whitespace-mangled patch, but please double check; I do not have any Darwin, so this hasn't even been compile tested. Also I have a small suggestion I'd like you to try on top of it, which I'll be sending in a separate message. Thanks. -- >8 -- From: Filipe Cabecinhas Date: Fri, 10 May 2013 15:24:57 -0700 Subject: [PATCH] compate/clipped-write.c: large write(2) fails on Mac OS X/XNU Due to a bug in the Darwin kernel, write(2) calls have a maximum size of INT_MAX bytes. Introduce a new compat function, clipped_write(), that only writes at most INT_MAX bytes and returns the number of bytes written, as a substitute for write(2), and allow platforms that need this to enable it from the build mechanism with NEEDS_CLIPPED_WRITE. Set it for Mac OS X by default. It may be necessary to include this function on Windows, too. Signed-off-by: Filipe Cabecinhas Signed-off-by: Junio C Hamano --- Makefile | 5 +++++ compat/clipped-write.c | 13 +++++++++++++ config.mak.uname | 1 + git-compat-util.h | 5 +++++ 4 files changed, 24 insertions(+) create mode 100644 compat/clipped-write.c diff --git a/Makefile b/Makefile index 26d3332..7076b15 100644 --- a/Makefile +++ b/Makefile @@ -1463,6 +1463,11 @@ ifndef NO_MSGFMT_EXTENDED_OPTIONS MSGFMT += --check --statistics endif +ifdef NEEDS_CLIPPED_WRITE + BASIC_CFLAGS += -DNEEDS_CLIPPED_WRITE + COMPAT_OBJS += compat/clipped-write.o +endif + ifneq (,$(XDL_FAST_HASH)) BASIC_CFLAGS += -DXDL_FAST_HASH endif diff --git a/compat/clipped-write.c b/compat/clipped-write.c new file mode 100644 index 0000000..9183698 --- /dev/null +++ b/compat/clipped-write.c @@ -0,0 +1,13 @@ +#include +#include + +/* + * Version of write that will write at most INT_MAX bytes. + * Workaround a xnu bug on Mac OS X + */ +ssize_t clipped_write(int fildes, const void *buf, size_t nbyte) +{ + if (nbyte > INT_MAX) + nbyte = INT_MAX; + return write(fildes, buf, nbyte); +} diff --git a/config.mak.uname b/config.mak.uname index e09af8f..e689a9a 100644 --- a/config.mak.uname +++ b/config.mak.uname @@ -95,6 +95,7 @@ ifeq ($(uname_S),Darwin) NO_MEMMEM = YesPlease USE_ST_TIMESPEC = YesPlease HAVE_DEV_TTY = YesPlease + NEEDS_CLIPPED_WRITE = YesPlease COMPAT_OBJS += compat/precompose_utf8.o BASIC_CFLAGS += -DPRECOMPOSE_UNICODE endif diff --git a/git-compat-util.h b/git-compat-util.h index b636e0d..3144b8d 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -181,6 +181,11 @@ typedef unsigned long uintptr_t; #define probe_utf8_pathname_composition(a,b) #endif +#ifdef NEEDS_CLIPPED_WRITE +ssize_t clipped_write(int fildes, const void *buf, size_t nbyte); +#define write(x,y,z) clipped_write((x),(y),(z)) +#endif + #ifdef MKDIR_WO_TRAILING_SLASH #define mkdir(a,b) compat_mkdir_wo_trailing_slash((a),(b)) extern int compat_mkdir_wo_trailing_slash(const char*, mode_t); -- 1.8.3-rc1-268-g30389da