From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1b9SHa-0003Ds-OY for mharc-qemu-trivial@gnu.org; Sun, 05 Jun 2016 03:15:38 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53513) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b9SHY-0003BE-3n for qemu-trivial@nongnu.org; Sun, 05 Jun 2016 03:15:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b9SHW-0005qo-4t for qemu-trivial@nongnu.org; Sun, 05 Jun 2016 03:15:35 -0400 Received: from isrv.corpit.ru ([86.62.121.231]:47178) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b9SHO-0005jV-Jt; Sun, 05 Jun 2016 03:15:26 -0400 Received: from [192.168.88.2] (mjt.vpn.tls.msk.ru [192.168.177.99]) by isrv.corpit.ru (Postfix) with ESMTP id 113F2408D7; Sun, 5 Jun 2016 10:15:08 +0300 (MSK) To: Fabien Siron , qemu-trivial@nongnu.org References: <1464790984-8123-1-git-send-email-fabien.siron@epita.fr> Cc: qemu-devel From: Michael Tokarev Openpgp: id=6EE195D1886E8FFB810D4324457CE0A0804465C5 Organization: Telecom Service, JSC Message-ID: <5753D17B.5070800@msgid.tls.msk.ru> Date: Sun, 5 Jun 2016 10:15:07 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.8.0 MIME-Version: 1.0 In-Reply-To: <1464790984-8123-1-git-send-email-fabien.siron@epita.fr> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 86.62.121.231 Subject: Re: [Qemu-trivial] [PATCH] pc: Use fstat in get_file_size() X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 05 Jun 2016 07:15:37 -0000 Please direct all patches to qemu-devel@ too, don't use ONLY qemu-trivial. Thanks. 01.06.2016 17:23, Fabien Siron wrote: > As mentioned in the comment, fstat is quite simpler than playing with > ftell() and fseek(). > > Signed-off-by: Fabien Siron > --- > hw/i386/pc.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index 99437e0..fecb067 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -801,16 +801,13 @@ static FWCfgState *bochs_bios_init(AddressSpace *as, PCMachineState *pcms) > > static long get_file_size(FILE *f) > { > - long where, size; > + struct stat stat; > + int fd; > > - /* XXX: on Unix systems, using fstat() probably makes more sense */ > + fd = fileno(f); > + fstat(fd, &stat); There's no need to introduce fd variable here, it is perfectly sane to use fstat(fileno(f), &stat) here. > - where = ftell(f); > - fseek(f, 0, SEEK_END); > - size = ftell(f); > - fseek(f, where, SEEK_SET); > - > - return size; > + return stat.st_size; Note there's no error checking in this function, neither in the original nor in the new implementation. But old function, in case of error, will most likely return -1 (error result of ftell()), while new function will return some random value. So the body should look something like: struct stat st; return fstat(fileno(f), &st) < 0 ? -1 : st.st_size; Thanks, /mjt From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53501) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b9SHV-0003B4-2s for qemu-devel@nongnu.org; Sun, 05 Jun 2016 03:15:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b9SHO-0005lE-Rm for qemu-devel@nongnu.org; Sun, 05 Jun 2016 03:15:31 -0400 References: <1464790984-8123-1-git-send-email-fabien.siron@epita.fr> From: Michael Tokarev Message-ID: <5753D17B.5070800@msgid.tls.msk.ru> Date: Sun, 5 Jun 2016 10:15:07 +0300 MIME-Version: 1.0 In-Reply-To: <1464790984-8123-1-git-send-email-fabien.siron@epita.fr> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] pc: Use fstat in get_file_size() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fabien Siron , qemu-trivial@nongnu.org Cc: qemu-devel Please direct all patches to qemu-devel@ too, don't use ONLY qemu-trivial. Thanks. 01.06.2016 17:23, Fabien Siron wrote: > As mentioned in the comment, fstat is quite simpler than playing with > ftell() and fseek(). > > Signed-off-by: Fabien Siron > --- > hw/i386/pc.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index 99437e0..fecb067 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -801,16 +801,13 @@ static FWCfgState *bochs_bios_init(AddressSpace *as, PCMachineState *pcms) > > static long get_file_size(FILE *f) > { > - long where, size; > + struct stat stat; > + int fd; > > - /* XXX: on Unix systems, using fstat() probably makes more sense */ > + fd = fileno(f); > + fstat(fd, &stat); There's no need to introduce fd variable here, it is perfectly sane to use fstat(fileno(f), &stat) here. > - where = ftell(f); > - fseek(f, 0, SEEK_END); > - size = ftell(f); > - fseek(f, where, SEEK_SET); > - > - return size; > + return stat.st_size; Note there's no error checking in this function, neither in the original nor in the new implementation. But old function, in case of error, will most likely return -1 (error result of ftell()), while new function will return some random value. So the body should look something like: struct stat st; return fstat(fileno(f), &st) < 0 ? -1 : st.st_size; Thanks, /mjt