From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from eggs.gnu.org (eggs.gnu.org [IPv6:2001:470:142:3::10]) by sourceware.org (Postfix) with ESMTPS id 6F7DB3858D32 for ; Sun, 12 Feb 2023 14:55:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 6F7DB3858D32 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gnu.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gnu.org Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pRDlB-00037Z-0N; Sun, 12 Feb 2023 09:55:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=In-Reply-To:MIME-Version:References:Subject:To:From: Date; bh=niBxeomgak0SZBBOR99iD46e0oIugaiXWKXdKmZqagw=; b=M/DtkaTj04BpTUtOBoyi fPAmr2qDLFtk1vEMrcmCJ9jX9MTlpJK3Xevo/bR42lLwLBLViWaV2y4S+h2+tq/pu/kkgx8AnVX5V wJhguyOU/nJx62qtGRwoVicf/u0/WzfjH4fZEmOEbfjiUnWpO9ynoKTW7qUMCxyLGN0G5XiOi405+ tjx5+SOGQ3vaAyL0y30XYn/PapePbC40UpDdOe/rCLvQ6+b6ZtnYKuU0PVjYz3cTah/If7O2JhFHQ dws6nmawtv6jKnK5hMYmPPiWg61sl8gM6iE1S0xkXWGzjEmCTopVtM2Ck6sE1ktwkAI6LOk57ObFV gpo3baerOaqbhg==; Received: from lfbn-bor-1-1163-184.w92-158.abo.wanadoo.fr ([92.158.138.184] helo=begin) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pRDlA-0001A8-Jj; Sun, 12 Feb 2023 09:55:20 -0500 Received: from samy by begin with local (Exim 4.96) (envelope-from ) id 1pRDl8-004nV9-0x; Sun, 12 Feb 2023 15:55:18 +0100 Date: Sun, 12 Feb 2023 15:55:18 +0100 From: Samuel Thibault To: Sergey Bugaev Cc: bug-hurd@gnu.org, libc-alpha@sourceware.org, =?utf-8?Q?Fl=C3=A1vio?= Cruz Subject: Re: [RFC PATCH glibc 3/12] mach, hurd: Cast through uintptr_t Message-ID: <20230212145518.kr7tora7x5edlcbn@begin> Mail-Followup-To: Sergey Bugaev , bug-hurd@gnu.org, libc-alpha@sourceware.org, =?utf-8?Q?Fl=C3=A1vio?= Cruz References: <20230212111044.610942-1-bugaevc@gmail.com> <20230212111044.610942-4-bugaevc@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230212111044.610942-4-bugaevc@gmail.com> Organization: I am not organized User-Agent: NeoMutt/20170609 (1.8.3) X-Spam-Status: No, score=-11.7 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Applied, thanks! Sergey Bugaev, le dim. 12 févr. 2023 14:10:34 +0300, a ecrit: > When casting between a pointer and an integer of a different size, GCC > emits a warning (which is escalated to a build failure by -Werror). > Indeed, if what you start with is a pointer, which you then cast to a > shorter integer and then back again, you're going to cut off some bits > of the pointer. > > But if you start with an integer (such as mach_port_t), then cast it to > a longer pointer (void *), and then back to a shorter integer, you are > fine. To keep GCC happy, cast through an intermediary uintptr_t, which > is always the same size as a pointer. > > Signed-off-by: Sergey Bugaev > --- > htl/cthreads-compat.c | 5 +++-- > hurd/fopenport.c | 15 ++++++++++----- > hurd/hurd/port.h | 2 +- > hurd/port-cleanup.c | 3 ++- > hurd/vpprintf.c | 6 ++++-- > mach/devstream.c | 9 +++++---- > 6 files changed, 25 insertions(+), 15 deletions(-) > > diff --git a/htl/cthreads-compat.c b/htl/cthreads-compat.c > index 55043a8b..2a0a95b6 100644 > --- a/htl/cthreads-compat.c > +++ b/htl/cthreads-compat.c > @@ -25,8 +25,9 @@ void > __cthread_detach (__cthread_t thread) > { > int err; > + pthread_t pthread = (pthread_t) (uintptr_t) thread; > > - err = __pthread_detach ((pthread_t) thread); > + err = __pthread_detach (pthread); > assert_perror (err); > } > weak_alias (__cthread_detach, cthread_detach) > @@ -40,7 +41,7 @@ __cthread_fork (__cthread_fn_t func, void *arg) > err = __pthread_create (&thread, NULL, func, arg); > assert_perror (err); > > - return (__cthread_t) thread; > + return (__cthread_t) (uintptr_t) thread; > } > weak_alias (__cthread_fork, cthread_fork) > > diff --git a/hurd/fopenport.c b/hurd/fopenport.c > index 60afb445..be6aa30c 100644 > --- a/hurd/fopenport.c > +++ b/hurd/fopenport.c > @@ -28,9 +28,10 @@ readio (void *cookie, char *buf, size_t n) > mach_msg_type_number_t nread; > error_t err; > char *bufp = buf; > + io_t io = (io_t) (uintptr_t) cookie; > > nread = n; > - if (err = __io_read ((io_t) cookie, &bufp, &nread, -1, n)) > + if (err = __io_read (io, &bufp, &nread, -1, n)) > return __hurd_fail (err); > > if (bufp != buf) > @@ -50,8 +51,9 @@ writeio (void *cookie, const char *buf, size_t n) > { > vm_size_t wrote; > error_t err; > + io_t io = (io_t) (uintptr_t) cookie; > > - if (err = __io_write ((io_t) cookie, buf, n, -1, &wrote)) > + if (err = __io_write (io, buf, n, -1, &wrote)) > return __hurd_fail (err); > > return wrote; > @@ -65,7 +67,8 @@ seekio (void *cookie, > off64_t *pos, > int whence) > { > - error_t err = __io_seek ((file_t) cookie, *pos, whence, pos); > + io_t io = (io_t) (uintptr_t) cookie; > + error_t err = __io_seek (io, *pos, whence, pos); > return err ? __hurd_fail (err) : 0; > } > > @@ -74,8 +77,9 @@ seekio (void *cookie, > static int > closeio (void *cookie) > { > + io_t io = (io_t) (uintptr_t) cookie; > error_t error = __mach_port_deallocate (__mach_task_self (), > - (mach_port_t) cookie); > + io); > if (error) > return __hurd_fail (error); > return 0; > @@ -127,6 +131,7 @@ __fopenport (mach_port_t port, const char *mode) > return NULL; > } > > - return fopencookie ((void *) port, mode, funcsio); > + return fopencookie ((void *) (uintptr_t) port, > + mode, funcsio); > } > weak_alias (__fopenport, fopenport) > diff --git a/hurd/hurd/port.h b/hurd/hurd/port.h > index fdba8db5..1e473978 100644 > --- a/hurd/hurd/port.h > +++ b/hurd/hurd/port.h > @@ -96,7 +96,7 @@ _hurd_port_locked_get (struct hurd_port *port, > if (result != MACH_PORT_NULL) > { > link->cleanup = &_hurd_port_cleanup; > - link->cleanup_data = (void *) result; > + link->cleanup_data = (void *) (uintptr_t) result; > _hurd_userlink_link (&port->users, link); > } > __spin_unlock (&port->lock); > diff --git a/hurd/port-cleanup.c b/hurd/port-cleanup.c > index 08ab3d47..ad43b830 100644 > --- a/hurd/port-cleanup.c > +++ b/hurd/port-cleanup.c > @@ -26,7 +26,8 @@ > void > _hurd_port_cleanup (void *cleanup_data, jmp_buf env, int val) > { > - __mach_port_deallocate (__mach_task_self (), (mach_port_t) cleanup_data); > + mach_port_t port = (mach_port_t) (uintptr_t) cleanup_data; > + __mach_port_deallocate (__mach_task_self (), port); > } > > /* We were cancelled while using a port, and called from the cleanup unwinding. > diff --git a/hurd/vpprintf.c b/hurd/vpprintf.c > index fe734946..010f04ca 100644 > --- a/hurd/vpprintf.c > +++ b/hurd/vpprintf.c > @@ -25,8 +25,9 @@ > static ssize_t > do_write (void *cookie, const char *buf, size_t n) > { > + io_t io = (io_t) (uintptr_t) cookie; > vm_size_t amount = n; > - error_t error = __io_write ((io_t) cookie, buf, n, -1, &amount); > + error_t error = __io_write (io, buf, n, -1, &amount); > if (error) > return __hurd_fail (error); > return n; > @@ -51,7 +52,8 @@ vpprintf (io_t port, const char *format, va_list arg) > #endif > > _IO_cookie_init (&temp_f.cfile, _IO_NO_READS, > - (void *) port, (cookie_io_functions_t) { write: do_write }); > + (void *) (uintptr_t) port, > + (cookie_io_functions_t) { write: do_write }); > > done = __vfprintf_internal (&temp_f.cfile.__fp.file, format, arg, 0); > > diff --git a/mach/devstream.c b/mach/devstream.c > index 09272d10..cfa9a4f4 100644 > --- a/mach/devstream.c > +++ b/mach/devstream.c > @@ -28,7 +28,7 @@ > static ssize_t > devstream_write (void *cookie, const char *buffer, size_t n) > { > - const device_t dev = (device_t) cookie; > + const device_t dev = (device_t) (uintptr_t) cookie; > > int write_some (const char *p, size_t to_write) > { > @@ -83,7 +83,7 @@ devstream_write (void *cookie, const char *buffer, size_t n) > static ssize_t > devstream_read (void *cookie, char *buffer, size_t to_read) > { > - const device_t dev = (device_t) cookie; > + const device_t dev = (device_t) (uintptr_t) cookie; > > kern_return_t err; > mach_msg_type_number_t nread = to_read; > @@ -112,7 +112,8 @@ devstream_read (void *cookie, char *buffer, size_t to_read) > static int > dealloc_ref (void *cookie) > { > - if (__mach_port_deallocate (mach_task_self (), (mach_port_t) cookie)) > + const device_t dev = (device_t) (uintptr_t) cookie; > + if (__mach_port_deallocate (mach_task_self (), dev)) > { > errno = EINVAL; > return -1; > @@ -131,7 +132,7 @@ mach_open_devstream (mach_port_t dev, const char *mode) > return NULL; > } > > - stream = _IO_fopencookie ((void *) dev, mode, > + stream = _IO_fopencookie ((void *) (uintptr_t) dev, mode, > (cookie_io_functions_t) { write: devstream_write, > read: devstream_read, > close: dealloc_ref }); > -- > 2.39.1 > > -- Samuel --- Pour une évaluation indépendante, transparente et rigoureuse ! Je soutiens la Commission d'Évaluation de l'Inria.