From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11908 invoked by alias); 30 Oct 2019 20:24:52 -0000 Mailing-List: contact glibc-cvs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: , Sender: glibc-cvs-owner@sourceware.org List-Subscribe: Received: (qmail 956 invoked by uid 9943); 30 Oct 2019 20:24:37 -0000 Date: Wed, 30 Oct 2019 20:24:00 -0000 Message-ID: <20191030202437.940.qmail@sourceware.org> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Adhemerval Zanella To: glibc-cvs@sourceware.org Subject: [glibc] Use clock_gettime to implement gettimeofday. X-Act-Checkin: glibc X-Git-Author: Adhemerval Zanella X-Git-Refname: refs/heads/master X-Git-Oldrev: 40a36935fff4eac83b9676b04048990ccb3c4754 X-Git-Newrev: 5e46749c64d51f50f8511ed99c1266d7c13e182b X-SW-Source: 2019-q4/txt/msg00209.txt.bz2 https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=5e46749c64d51f50f8511ed99c1266d7c13e182b commit 5e46749c64d51f50f8511ed99c1266d7c13e182b Author: Adhemerval Zanella Date: Thu Oct 24 19:19:33 2019 +0000 Use clock_gettime to implement gettimeofday. Consolidate generic gettimeofday implementation to use clock_gettime. Linux ports that still provide gettimeofday through vDSO are not changed. Remove sysdeps/unix/clock_gettime.c, which implemented clock_gettime using gettimeofday; new OS ports must provide a real implementation of clock_gettime. Rename sysdeps/mach/gettimeofday.c to sysdeps/mach/clock_gettime.c and convert into an implementation of clock_gettime. It only supports CLOCK_REALTIME; Mach does not appear to have any support for monotonic clocks. It uses __host_get_time, which provides at best microsecond resolution. Hurd is currently using sysdeps/posix/clock_getres.c for clock_getres; its output for CLOCK_REALTIME is based on sysconf (_SC_CLK_TCK), and I do not know whether that gives the correct result. Unlike settimeofday, there are no known uses of gettimeofday's vestigial "get time zone" feature that are not bugs. (The per-process timezone support in localtime and friends is unrelated, and the programs that set the kernel's offset between the hardware clock and UTC do not need to read it back.) Therefore, this feature is dummied out. Henceforth, if gettimeofday's "struct timezone" argument is not NULL, it will write zeroes to both fields. Any program that is actually looking at this data will thus think it is running in UTC, which is probably more correct than whatever it was doing before. [__]gettimeofday no longer has any internal callers, so we can now remove its internal prototype and PLT bypass aliases. The __gettimeofday@GLIBC_2.0 export remains, in case it is used by any third-party code. It also allows to simplify the arch-specific implementation on x86 and powerpc to remove the hack to disable the internal route to non iFUNC variant for internal symbol. This patch also fixes a missing optimization on aarch64, powerpc, and x86 where the code used on static build do not use the vDSO. Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu, and aarch64-linux-gnu. Co-authored-by: Zack Weinberg Reviewed-by: Lukasz Majewski Diff: --- NEWS | 13 ++++ include/sys/time.h | 2 - sysdeps/{unix => mach}/clock_gettime.c | 37 +++++------- sysdeps/mach/gettimeofday.c | 43 -------------- sysdeps/posix/gettimeofday.c | 67 --------------------- sysdeps/unix/syscalls.list | 1 - sysdeps/unix/sysv/linux/aarch64/gettimeofday.c | 34 +++++------ .../unix/sysv/linux/{i386 => alpha}/gettimeofday.c | 25 ++------ sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c | 11 +++- sysdeps/unix/sysv/linux/alpha/tv32-compat.h | 6 ++ sysdeps/unix/sysv/linux/gettimeofday.c | 49 --------------- sysdeps/unix/sysv/linux/powerpc/gettimeofday.c | 69 ++++++---------------- sysdeps/unix/sysv/linux/x86/gettimeofday.c | 43 ++++++-------- sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c | 1 + sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list | 1 - time/gettimeofday.c | 32 ++++++---- 16 files changed, 125 insertions(+), 309 deletions(-) diff --git a/NEWS b/NEWS index 7e9d36e..75b380c 100644 --- a/NEWS +++ b/NEWS @@ -21,6 +21,19 @@ Major new features: 18661-1:2014 and TS 18661-3:2015 as amended by the resolution of Clarification Request 13 to TS 18661-3. +* The gettimeofday function will no longer report information about a + system-wide time zone, expect for aarch64, powerpc, and x86 on Linux + which still uses the vDSO symbol (when available). + + This 4.2-BSD-era feature has been deprecated for many years, as it cannot + handle the full complexity of the world's timezones, but hitherto we have + supported it on a best-effort basis. Changes required to support 64-bit + time_t on 32-bit architectures have made this no longer practical. + + As of this release, callers of gettimeofday with a non-null 'tzp' argument + will always receive a 'struct timezone' whose tz_minuteswest and + tz_dsttime fields are zero. + Deprecated and removed features, and other changes affecting compatibility: * The totalorder and totalordermag functions, and the corresponding diff --git a/include/sys/time.h b/include/sys/time.h index c0e30e7..2bf4297 100644 --- a/include/sys/time.h +++ b/include/sys/time.h @@ -22,8 +22,6 @@ # ifndef _ISOMAC extern int __gettimeofday (struct timeval *__tv, struct timezone *__tz); -libc_hidden_proto (__gettimeofday) -libc_hidden_proto (gettimeofday) extern int __settimezone (const struct timezone *__tz) attribute_hidden; extern int __adjtime (const struct timeval *__delta, diff --git a/sysdeps/unix/clock_gettime.c b/sysdeps/mach/clock_gettime.c similarity index 65% rename from sysdeps/unix/clock_gettime.c rename to sysdeps/mach/clock_gettime.c index aa74e11..0f872e5 100644 --- a/sysdeps/unix/clock_gettime.c +++ b/sysdeps/mach/clock_gettime.c @@ -1,5 +1,4 @@ -/* clock_gettime -- Get the current time from a POSIX clockid_t. Unix version. - Copyright (C) 1999-2019 Free Software Foundation, Inc. +/* Copyright (C) 1991-2019 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -18,32 +17,28 @@ #include #include -#include +#include #include -/* Get current value of CLOCK and store it in TP. */ +/* Get the current time of day, putting it into *TS. + Returns 0 on success, -1 on errors. */ int -__clock_gettime (clockid_t clock_id, struct timespec *tp) +__clock_gettime (clockid_t clock_id, struct timespec *ts) { - int retval = -1; - - switch (clock_id) + if (clock_id != CLOCK_REALTIME) { - case CLOCK_REALTIME: - { - struct timeval tv; - retval = __gettimeofday (&tv, NULL); - if (retval == 0) - TIMEVAL_TO_TIMESPEC (&tv, tp); - } - break; - - default: - __set_errno (EINVAL); - break; + errno = EINVAL; + return -1; } - return retval; + /* __host_get_time can only fail if passed an invalid host_t. + __mach_host_self could theoretically fail (producing an + invalid host_t) due to resource exhaustion, but we assume + this will never happen. */ + time_value_t tv; + __host_get_time (__mach_host_self (), &tv); + TIME_VALUE_TO_TIMESPEC (&tv, ts); + return 0; } libc_hidden_def (__clock_gettime) diff --git a/sysdeps/mach/gettimeofday.c b/sysdeps/mach/gettimeofday.c deleted file mode 100644 index f6df003..0000000 --- a/sysdeps/mach/gettimeofday.c +++ /dev/null @@ -1,43 +0,0 @@ -/* Copyright (C) 1991-2019 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include -#include -#include - -/* Get the current time of day and timezone information, - putting it into *TV and *TZ. If TZ is NULL, *TZ is not filled. - Returns 0 on success, -1 on errors. */ -int -__gettimeofday (struct timeval *tv, struct timezone *tz) -{ - kern_return_t err; - - if (tz != NULL) - *tz = (struct timezone){0, 0}; /* XXX */ - - if (err = __host_get_time (__mach_host_self (), (time_value_t *) tv)) - { - errno = err; - return -1; - } - return 0; -} -libc_hidden_def (__gettimeofday) -weak_alias (__gettimeofday, gettimeofday) -libc_hidden_weak (gettimeofday) diff --git a/sysdeps/posix/gettimeofday.c b/sysdeps/posix/gettimeofday.c deleted file mode 100644 index 6bb98cd..0000000 --- a/sysdeps/posix/gettimeofday.c +++ /dev/null @@ -1,67 +0,0 @@ -/* Copyright (C) 1991-2019 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include -#include - -/* Get the current time of day and timezone information, - putting it into *TV and *TZ. If TZ is NULL, *TZ is not filled. - Returns 0 on success, -1 on errors. */ -int -__gettimeofday (struct timeval *tv, struct timezone *tz) -{ - if (tv == NULL) - { - __set_errno (EINVAL); - return -1; - } - - tv->tv_sec = (long int) time ((time_t *) NULL); - tv->tv_usec = 0L; - - if (tz != NULL) - { - const time_t timer = tv->tv_sec; - struct tm tm; - const struct tm *tmp; - - const long int save_timezone = __timezone; - const long int save_daylight = __daylight; - char *save_tzname[2]; - save_tzname[0] = __tzname[0]; - save_tzname[1] = __tzname[1]; - - tmp = localtime_r (&timer, &tm); - - tz->tz_minuteswest = __timezone / 60; - tz->tz_dsttime = __daylight; - - __timezone = save_timezone; - __daylight = save_daylight; - __tzname[0] = save_tzname[0]; - __tzname[1] = save_tzname[1]; - - if (tmp == NULL) - return -1; - } - - return 0; -} -libc_hidden_def (__gettimeofday) -weak_alias (__gettimeofday, gettimeofday) -libc_hidden_weak (gettimeofday) diff --git a/sysdeps/unix/syscalls.list b/sysdeps/unix/syscalls.list index 5fedd57..e28e801 100644 --- a/sysdeps/unix/syscalls.list +++ b/sysdeps/unix/syscalls.list @@ -33,7 +33,6 @@ getrlimit - getrlimit i:ip __getrlimit getrlimit getrusage - getrusage i:ip __getrusage getrusage getsockname - getsockname i:ibN __getsockname getsockname getsockopt - getsockopt i:iiiBN getsockopt -gettimeofday - gettimeofday i:pP __gettimeofday gettimeofday getuid - getuid Ei: __getuid getuid ioctl - ioctl i:iiI __ioctl ioctl kill - kill i:ii __kill kill diff --git a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c index 4ff74fa..075af3d 100644 --- a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c +++ b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c @@ -20,39 +20,39 @@ putting it into *tv and *tz. If tz is null, *tz is not filled. Returns 0 on success, -1 on errors. */ -#include +#include +#include -#ifdef SHARED - -# include -# include +#ifdef HAVE_GETTIMEOFDAY_VSYSCALL +# define HAVE_VSYSCALL +#endif +#include /* Used as a fallback in the ifunc resolver if VDSO is not available and for libc.so internal __gettimeofday calls. */ - static int __gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz) { + if (__glibc_unlikely (tz != 0)) + memset (tz, 0, sizeof *tz); + return INLINE_VSYSCALL (gettimeofday, 2, tv, tz); } +#ifdef SHARED +# include +# include + # define INIT_ARCH() -libc_ifunc_hidden (__gettimeofday, __gettimeofday, - (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL) - ?: __gettimeofday_vsyscall)) -libc_hidden_def (__gettimeofday) +libc_ifunc (__gettimeofday, + (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL) + ?: __gettimeofday_vsyscall)) #else - -# include int __gettimeofday (struct timeval *tv, struct timezone *tz) { - return INLINE_SYSCALL (gettimeofday, 2, tv, tz); + return __gettimeofday_vsyscall (tv, tz); } -libc_hidden_def (__gettimeofday) - #endif - weak_alias (__gettimeofday, gettimeofday) -libc_hidden_weak (gettimeofday) diff --git a/sysdeps/unix/sysv/linux/i386/gettimeofday.c b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c similarity index 58% rename from sysdeps/unix/sysv/linux/i386/gettimeofday.c rename to sysdeps/unix/sysv/linux/alpha/gettimeofday.c index f6faecb..262a3c2 100644 --- a/sysdeps/unix/sysv/linux/i386/gettimeofday.c +++ b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c @@ -1,5 +1,5 @@ -/* gettimeofday - get the time. Linux/i386 version. - Copyright (C) 2015-2019 Free Software Foundation, Inc. +/* gettimeofday -- Get the current time of day. Linux/Alpha/tv64 version. + Copyright (C) 2019 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -16,20 +16,7 @@ License along with the GNU C Library; if not, see . */ -#ifdef SHARED -# define __gettimeofday __redirect___gettimeofday -#endif - -#include - -#ifdef SHARED -# undef __gettimeofday -# define __gettimeofday_type __redirect___gettimeofday - -# undef libc_hidden_def -# define libc_hidden_def(name) \ - __hidden_ver1 (__gettimeofday_syscall, __GI___gettimeofday, \ - __gettimeofday_syscall); -#endif - -#include +/* We can use the generic implementation, but we have to override its + default symbol version. */ +#define VERSION_gettimeofday GLIBC_2.1 +#include