From patchwork Fri Apr 9 11:36:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 42934 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 195F1398B42E; Fri, 9 Apr 2021 11:36:49 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 195F1398B42E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1617968209; bh=yJFVhid/3Qok/PB/REbYtdq3ENEjrGsTqj0OeemII9E=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:Cc:From; b=Ho/+yM3dr+da5iNSoZqPFFDD9QokaCmsL6WBTctfANCN17NQuhnLGbjB6x1w7O9P+ V6JPYcMeIQ10k9GfhBFV5pCMfSoKLaXGgRSfZMf3bJPSrwTJxOTbxcscfWCMJp1H/v rKVUYFetg+BqWeD2T5d9lOyrxyJeU1IycjfNKBMQ= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-qk1-x72d.google.com (mail-qk1-x72d.google.com [IPv6:2607:f8b0:4864:20::72d]) by sourceware.org (Postfix) with ESMTPS id D7992385702E for ; Fri, 9 Apr 2021 11:36:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org D7992385702E Received: by mail-qk1-x72d.google.com with SMTP id o5so5482179qkb.0 for ; Fri, 09 Apr 2021 04:36:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=yJFVhid/3Qok/PB/REbYtdq3ENEjrGsTqj0OeemII9E=; b=pnO3BD8LL62SJU8r5f7WIOIoJYlxUtBGhT9ZuyELjh6sTdouGd6YtQZ/HF7+SxMYJq iCNotTJ3r/aCMVN+VRHRavKMdZlRrT9Zz//t8YIM78WOr69daocigbKRvjE3+hWGPNGb R1G4dU8EYFQFGBqI/lgRbqc8vYyS4bf8jK0p1H42hn14QjAYH9rHZfu/TZDK/k/mr/ph qtYCOBMgWwhfuQYGH8S6HEeFqCQarFjjvcEbk/3X1tlhCaYkDyvF+fu0CwsCcgkKf/i4 QDDYGU+FQaNi2AYmCqypoen1NN6JRbA+xHmtJtWR0/Q9egeBxOsvnvm9IA+6twG/+OTj /qBQ== X-Gm-Message-State: AOAM531xlyeqsbfKd9nqJuJQkfq727d+uBN4lEmUEMELJMDhP0KiE+vi b15cELrbRhbmNqcBqvlGnWrk/uvV6s2EURZT X-Google-Smtp-Source: ABdhPJyftrdh6m5sYcVV4thl8upesmfqEicGXLwixdZSG1mZdw1YbKM02Jc/9+18nEchzdelvbpN9Q== X-Received: by 2002:a37:db11:: with SMTP id e17mr1691878qki.421.1617968204705; Fri, 09 Apr 2021 04:36:44 -0700 (PDT) Received: from localhost.localdomain ([177.194.41.149]) by smtp.googlemail.com with ESMTPSA id n9sm1450226qkk.92.2021.04.09.04.36.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Apr 2021 04:36:44 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH v2 1/2] linux: Normalize and return timeout on select (BZ #27651) Date: Fri, 9 Apr 2021 08:36:38 -0300 Message-Id: <20210409113639.1124756-1-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-Spam-Status: No, score=-12.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Netto Reply-To: Adhemerval Zanella Cc: Andreas Schwab Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" The commit 2433d39b697, which added time64 support to select, changed the function to use __NR_pselect6 (or __NR_pelect6_time64) on all architectures. However, on architectures where the symbol was implemented with __NR_select the kernel normalizes the passed timeout instead of return EINVAL. For instance, the input timeval { 0, 5000000 } is interpreted as { 5, 0 }. And as indicated by BZ #27651, this semantic seems to be expected and changing it results in some performance issues (most likely the program does not check the return code and keeps issuing select with unormalized tv_usec argument). To avoid a different semantic depending whether which syscall the architecture used to issue, select now always normalize the timeout input. This is a slight change for some ABIs (for instance aarch64). Checked on x86_64-linux-gnu and i686-linux-gnu. --- include/time.h | 5 +++ misc/tst-select.c | 17 +++++++++ sunrpc/svcauth_des.c | 1 - support/Makefile | 2 ++ support/support.h | 8 +++++ support/support_select_modify_timeout.c | 29 ++++++++++++++++ support/support_select_normalize_timeout.c | 29 ++++++++++++++++ sysdeps/unix/sysv/linux/select.c | 40 ++++++++++++++++++---- 8 files changed, 123 insertions(+), 8 deletions(-) create mode 100644 support/support_select_modify_timeout.c create mode 100644 support/support_select_normalize_timeout.c diff --git a/include/time.h b/include/time.h index caf2af5e74..e0636132a6 100644 --- a/include/time.h +++ b/include/time.h @@ -502,6 +502,11 @@ time_now (void) __clock_gettime (TIME_CLOCK_GETTIME_CLOCKID, &ts); return ts.tv_sec; } + +#define NSEC_PER_SEC 1000000000L /* Nanoseconds per second. */ +#define USEC_PER_SEC 1000000L /* Microseconds per second. */ +#define NSEC_PER_USEC 1000L /* Nanoseconds per microsecond. */ + #endif #endif diff --git a/misc/tst-select.c b/misc/tst-select.c index 5ad057cd51..dc7717a7a6 100644 --- a/misc/tst-select.c +++ b/misc/tst-select.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -47,6 +48,12 @@ do_test_child (void *clousure) int r = select (args->fds[0][0] + 1, &rfds, NULL, NULL, &args->tmo); TEST_COMPARE (r, 0); + if (support_select_modify_timeout ()) + { + TEST_COMPARE (args->tmo.tv_sec, 0); + TEST_COMPARE (args->tmo.tv_usec, 0); + } + TEST_TIMESPEC_NOW_OR_AFTER (CLOCK_REALTIME, ts); xwrite (args->fds[1][1], "foo", 3); @@ -69,6 +76,16 @@ do_test (void) sc_allow_none); } + if (support_select_normalize_timeout ()) + { + /* This is handled as 1 second instead of failing with EINVAL. */ + args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 1000000 }; + struct support_capture_subprocess result; + result = support_capture_subprocess (do_test_child, &args); + support_capture_subprocess_check (&result, "tst-select-child", 0, + sc_allow_none); + } + /* Same as before, but simulating polling. */ args.tmo = (struct timeval) { .tv_sec = 0, .tv_usec = 0 }; { diff --git a/sunrpc/svcauth_des.c b/sunrpc/svcauth_des.c index 7607abc818..25a85c9097 100644 --- a/sunrpc/svcauth_des.c +++ b/sunrpc/svcauth_des.c @@ -58,7 +58,6 @@ #define debug(msg) /*printf("svcauth_des: %s\n", msg) */ -#define USEC_PER_SEC ((uint32_t) 1000000L) #define BEFORE(t1, t2) timercmp(t1, t2, <) /* diff --git a/support/Makefile b/support/Makefile index 900e17f94f..1e2fc97ee6 100644 --- a/support/Makefile +++ b/support/Makefile @@ -68,6 +68,8 @@ libsupport-routines = \ support_quote_string \ support_record_failure \ support_run_diff \ + support_select_modify_timeout \ + support_select_normalize_timeout \ support_set_small_thread_stack_size \ support_shared_allocate \ support_small_stack_thread_attribute \ diff --git a/support/support.h b/support/support.h index e023d00857..f983783d64 100644 --- a/support/support.h +++ b/support/support.h @@ -144,6 +144,14 @@ static __inline bool support_path_support_time64 (const char *path) /* Return true if stat supports nanoseconds resolution. */ extern bool support_stat_nanoseconds (const char *path); +/* Return true if select modify the timeout to reflect the amount of time + no slept. */ +extern bool support_select_modify_timeout (void); + +/* Return true if select normalize the timeout input by taking in account + tv_usec larger than 1000000. */ +extern bool support_select_normalize_timeout (void); + __END_DECLS #endif /* SUPPORT_H */ diff --git a/support/support_select_modify_timeout.c b/support/support_select_modify_timeout.c new file mode 100644 index 0000000000..d70a5a5068 --- /dev/null +++ b/support/support_select_modify_timeout.c @@ -0,0 +1,29 @@ +/* Return whether select modify the timeout. + Copyright (C) 2021 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 + +bool +support_select_modify_timeout (void) +{ +#ifdef __linux__ + return true; +#else + return false; +#endif +} diff --git a/support/support_select_normalize_timeout.c b/support/support_select_normalize_timeout.c new file mode 100644 index 0000000000..447e3ec3e3 --- /dev/null +++ b/support/support_select_normalize_timeout.c @@ -0,0 +1,29 @@ +/* Return whether select normalize the timeout. + Copyright (C) 2021 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 + +bool +support_select_normalize_timeout (void) +{ +#ifdef __linux__ + return true; +#else + return false; +#endif +} diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c index 415aa87d3c..d075270ff4 100644 --- a/sysdeps/unix/sysv/linux/select.c +++ b/sysdeps/unix/sysv/linux/select.c @@ -33,12 +33,34 @@ int __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct __timeval64 *timeout) { - struct __timespec64 ts64, *pts64 = NULL; - if (timeout != NULL) + __time64_t s = timeout != NULL ? timeout->tv_sec : 0; + int32_t us = timeout != NULL ? timeout->tv_usec : 0; + int32_t ns; + + if (s < 0 || us < 0) + return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL); + + /* Normalize the timeout, as legacy Linux __NR_select and __NR__newselect. + Different than syscall, it also handle possible overflow. */ + if (us / USEC_PER_SEC > INT64_MAX - s) { - ts64 = timeval64_to_timespec64 (*timeout); - pts64 = &ts64; + s = INT64_MAX; + ns = NSEC_PER_SEC - 1; } + else + { + s += us / USEC_PER_SEC; + us = us % USEC_PER_SEC; + ns = us * NSEC_PER_USEC; + } + + struct __timespec64 ts64, *pts64 = NULL; + if (timeout != NULL) + { + ts64.tv_sec = s; + ts64.tv_nsec = ns; + pts64 = &ts64; + } #ifndef __NR_pselect6_time64 # define __NR_pselect6_time64 __NR_pselect6 @@ -52,10 +74,13 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, (though the pselect() glibc call suppresses this behavior). Since select() on Linux has the same behavior as the pselect6 syscall, we update the timeout here. */ - if (r == 0 || errno != ENOSYS) + if (r >= 0 || errno != ENOSYS) { if (timeout != NULL) - TIMEVAL_TO_TIMESPEC (timeout, &ts64); + { + timeout->tv_sec = ts64.tv_sec; + timeout->tv_usec = ts64.tv_nsec / NSEC_PER_USEC; + } return r; } @@ -71,7 +96,8 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, __set_errno (EINVAL); return -1; } - ts32 = valid_timespec64_to_timespec (ts64); + ts32.tv_sec = s; + ts32.tv_nsec = ns; pts32 = &ts32; } # ifndef __ASSUME_PSELECT From patchwork Fri Apr 9 11:36:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 42935 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 9CC98385DC2E; Fri, 9 Apr 2021 11:36:49 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9CC98385DC2E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1617968209; bh=q03/tsUlcCjf7YhY/JPjnWbsdlsQCwvYU3X7ZUzI7WI=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=KR7etVDO//UhKWPzxA36pcNIhd3xtLvlaQs9x/oKpWfSAXp9wPw8ubGpW+V0HyfiS atEOkpfHmvOoThcStjvHe08NIjm7H77ns326Mpg5qDMlzvv67yqSs0EbRlGS38LDuS 2J+r+KNhJ2K0foCRSAb8FI4KKC4np27gvFftaMnE= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-qt1-x836.google.com (mail-qt1-x836.google.com [IPv6:2607:f8b0:4864:20::836]) by sourceware.org (Postfix) with ESMTPS id 9FECE385DC2E for ; Fri, 9 Apr 2021 11:36:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 9FECE385DC2E Received: by mail-qt1-x836.google.com with SMTP id u8so3852896qtq.12 for ; Fri, 09 Apr 2021 04:36:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=q03/tsUlcCjf7YhY/JPjnWbsdlsQCwvYU3X7ZUzI7WI=; b=QspLYHn6YMUKT6zqv50VOzZ1WG1r+QBpC3oHwCrrBpyqbaVqewcK98H2OE68gA8QR0 Sxx+g4a4Wy9gGFZBzFW62/uXumGTDP5pE/8eLBH2EwJNhR7UVnZl5apfcqVZ8rA6xhH6 c1Z4gU/pDkpKE82BQUgI9B9dBNR9UNiN9qpcbRKszR2YaZ5SNANrzd8Hh0wQZyZcZ0bx K++P9VG0hrN2RikuxRu0yUdXsZ9WKUPO0OSlToU0x3HeKWyqOtpgHlqHTfQytW/+1PjT nfJ3TxEPgi17JQxLBoG5TkSSB7g5s6SOY/ugC5HLV3nZxrNRzMDh90Z56PjuRbn4nq2P VcdA== X-Gm-Message-State: AOAM533d3qlrOB96LiqLJeIvYyOfBpuFD5SjfBDw7tPnmS9gfPMfVWqq vWPWfIlPl8wl04klDkTHmQ8EDjF78OUljqU1 X-Google-Smtp-Source: ABdhPJxRcB3jyjfDZpjBshuELtIAfw0EC14gTp9ywsU60Jk7AKEhYZkAT5JHVKWZhgr/MYgjwSdR9A== X-Received: by 2002:ac8:6a04:: with SMTP id t4mr12432210qtr.258.1617968206065; Fri, 09 Apr 2021 04:36:46 -0700 (PDT) Received: from localhost.localdomain ([177.194.41.149]) by smtp.googlemail.com with ESMTPSA id n9sm1450226qkk.92.2021.04.09.04.36.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Apr 2021 04:36:45 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH v2 2/2] linux: always update select timeout (BZ #27706) Date: Fri, 9 Apr 2021 08:36:39 -0300 Message-Id: <20210409113639.1124756-2-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210409113639.1124756-1-adhemerval.zanella@linaro.org> References: <20210409113639.1124756-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-12.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Netto Reply-To: Adhemerval Zanella Cc: Andreas Schwab Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" The timeout should be updated even on failure for time64 support. Checked on i686-linux-gnu. --- misc/tst-select.c | 30 ++++++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/select.c | 4 ++-- 2 files changed, 32 insertions(+), 2 deletions(-) diff --git a/misc/tst-select.c b/misc/tst-select.c index dc7717a7a6..9c817f4035 100644 --- a/misc/tst-select.c +++ b/misc/tst-select.c @@ -23,6 +23,7 @@ #include #include #include +#include struct child_args { @@ -30,6 +31,12 @@ struct child_args struct timeval tmo; }; +static void +alarm_handler (int signum) +{ + /* Do nothing. */ +} + static void do_test_child (void *clousure) { @@ -59,6 +66,22 @@ do_test_child (void *clousure) xwrite (args->fds[1][1], "foo", 3); } +static void +do_test_child_alarm (void *clousure) +{ + struct sigaction act = { .sa_handler = alarm_handler }; + xsigaction (SIGALRM, &act, NULL); + alarm (1); + + struct timeval tv = { .tv_sec = 10, .tv_usec = 0 }; + int r = select (0, NULL, NULL, NULL, &tv); + TEST_COMPARE (r, -1); + TEST_COMPARE (errno, EINTR); + + if (support_select_modify_timeout ()) + TEST_VERIFY (tv.tv_sec < 10); +} + static int do_test (void) { @@ -98,6 +121,13 @@ do_test (void) xclose (args.fds[0][0]); xclose (args.fds[1][1]); + { + struct support_capture_subprocess result; + result = support_capture_subprocess (do_test_child_alarm, NULL); + support_capture_subprocess_check (&result, "tst-select-child", 0, + sc_allow_none); + } + { fd_set rfds; FD_ZERO (&rfds); diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c index d075270ff4..4e426f9aed 100644 --- a/sysdeps/unix/sysv/linux/select.c +++ b/sysdeps/unix/sysv/linux/select.c @@ -110,7 +110,7 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, pts32, NULL); # endif - if (r >= 0 && timeout != NULL) + if (timeout != NULL) *timeout = valid_timespec_to_timeval64 (ts32); #endif @@ -131,7 +131,7 @@ __select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, ptv64 = &tv64; } int r = __select64 (nfds, readfds, writefds, exceptfds, ptv64); - if (r >= 0 && timeout != NULL) + if (timeout != NULL) /* The remanining timeout will be always less the input TIMEOUT. */ *timeout = valid_timeval64_to_timeval (tv64); return r;