From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MGvA8-0004N0-QR for qemu-devel@nongnu.org; Wed, 17 Jun 2009 09:26:48 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MGvA4-0004Ka-1o for qemu-devel@nongnu.org; Wed, 17 Jun 2009 09:26:48 -0400 Received: from [199.232.76.173] (port=57600 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MGvA3-0004KV-Qx for qemu-devel@nongnu.org; Wed, 17 Jun 2009 09:26:43 -0400 Received: from mail-qy0-f191.google.com ([209.85.221.191]:45123) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1MGvA3-0001dm-Dw for qemu-devel@nongnu.org; Wed, 17 Jun 2009 09:26:43 -0400 Received: by qyk29 with SMTP id 29so353869qyk.4 for ; Wed, 17 Jun 2009 06:26:41 -0700 (PDT) Message-ID: <4A38EF0D.30804@codemonkey.ws> Date: Wed, 17 Jun 2009 08:26:37 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH v3] avoid compilation warning/errors on up to date compilers/glibc References: <200906170803.49389.jcd@tribudubois.net> In-Reply-To: <200906170803.49389.jcd@tribudubois.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jean-Christophe Dubois Cc: qemu-devel@nongnu.org Jean-Christophe Dubois wrote: > Some system calls are now requiring to have their return value checked. > > Without this a warning is emitted and in the case a qemu an error is > triggered as qemu is considering warnings as errors. > > For example: > > block/cow.c: In function ‘cow_create’: > block/cow.c:251: error: ignoring return value of ‘write’, declared with > attribute warn_unused_result > block/cow.c:253: error: ignoring return value of ‘ftruncate’, declared > with attribute warn_unused_result > > This is an attempt at removing all these warnings to allow a clean > compilation with up to date compilers/distributions. > > The second version fixes an error detected by Stuart Brady as well > as some coding style issues. Note however that some of the > modified files don't follow the qemu coding style (using tabs > instead of spaces). > > The Third version add one ftruncate() system call error handling that > was missing from V2 (in block/vvfat.c). > > Signed-off-by: Jean-Christophe DUBOIS > > --- > block.c | 3 ++- > block/bochs.c | 3 ++- > block/cow.c | 12 ++++++++++-- > block/qcow.c | 22 ++++++++++++++++------ > block/qcow2.c | 37 +++++++++++++++++++++++++++++-------- > block/raw-posix.c | 9 ++++++--- > block/vmdk.c | 38 ++++++++++++++++++++++++++++---------- > block/vvfat.c | 24 +++++++++++++++++------- > linux-user/mmap.c | 7 +++++-- > linux-user/path.c | 6 +++++- > osdep.c | 5 ++++- > slirp/misc.c | 3 ++- > usb-linux.c | 3 +-- > vl.c | 14 ++++++++++---- > 14 files changed, 137 insertions(+), 49 deletions(-) > > diff --git a/block.c b/block.c > index aca5a6d..c78d66a 100644 > --- a/block.c > +++ b/block.c > @@ -371,7 +371,8 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags, > snprintf(backing_filename, sizeof(backing_filename), > "%s", filename); > else > - realpath(filename, backing_filename); > + if (!realpath(filename, backing_filename)) > + return -1; > > bdrv_qcow2 = bdrv_find_format("qcow2"); > options = parse_option_parameters("", bdrv_qcow2->create_options, NULL); > diff --git a/block/bochs.c b/block/bochs.c > index bac81c4..0d614eb 100644 > --- a/block/bochs.c > +++ b/block/bochs.c > @@ -199,7 +199,8 @@ static inline int seek_to_sector(BlockDriverState *bs, int64_t sector_num) > // read in bitmap for current extent > lseek(s->fd, bitmap_offset + (extent_offset / 8), SEEK_SET); > > - read(s->fd, &bitmap_entry, 1); > + if (read(s->fd, &bitmap_entry, 1) != 1) > + return -1; // not allocated > This is no more correct than before. read() can return EINTR and that should be handled appropriately. Elsewhere, read() can return partial results and we ought to handle that properly. Using -D_FORTIFY_SOURCES=0 will eliminate these warnings. If we're going to fix these things, we should fix them properly. Regards, Anthony Liguori