From 436a604b7dc741fc76b5a6704c6cd8bb178518e7 Mon Sep 17 00:00:00 2001 From: Adam Yi Date: Tue, 7 Mar 2023 07:30:02 -0500 Subject: posix: Fix system blocks SIGCHLD erroneously [BZ #30163] Fix bug that SIGCHLD is erroneously blocked forever in the following scenario: 1. Thread A calls system but hasn't returned yet 2. Thread B calls another system but returns SIGCHLD would be blocked forever in thread B after its system() returns, even after the system() in thread A returns. Although POSIX does not require, glibc system implementation aims to be thread and cancellation safe. This bug was introduced in 5fb7fc96350575c9adb1316833e48ca11553be49 when we moved reverting signal mask to happen when the last concurrently running system returns, despite that signal mask is per thread. This commit reverts this logic and adds a test. Signed-off-by: Adam Yi Reviewed-by: Adhemerval Zanella --- support/Makefile | 2 ++ support/dtotimespec-time64.c | 27 ++++++++++++++++++++++++ support/dtotimespec.c | 50 ++++++++++++++++++++++++++++++++++++++++++++ support/shell-container.c | 28 +++++++++++++++++++++++++ support/timespec.h | 4 ++++ 5 files changed, 111 insertions(+) create mode 100644 support/dtotimespec-time64.c create mode 100644 support/dtotimespec.c (limited to 'support') diff --git a/support/Makefile b/support/Makefile index d52c472755..05b31159ea 100644 --- a/support/Makefile +++ b/support/Makefile @@ -32,6 +32,8 @@ libsupport-routines = \ check_hostent \ check_netent \ delayed_exit \ + dtotimespec \ + dtotimespec-time64 \ ignore_stderr \ next_to_fault \ oom_error \ diff --git a/support/dtotimespec-time64.c b/support/dtotimespec-time64.c new file mode 100644 index 0000000000..b3d5e351e3 --- /dev/null +++ b/support/dtotimespec-time64.c @@ -0,0 +1,27 @@ +/* Convert double to timespec. 64-bit time support. + Copyright (C) 2011-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library and is also part of gnulib. + Patches to this file should be submitted to both projects. + + 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 + +#if __TIMESIZE != 64 +# define timespec __timespec64 +# define time_t __time64_t +# define dtotimespec dtotimespec_time64 +# include "dtotimespec.c" +#endif diff --git a/support/dtotimespec.c b/support/dtotimespec.c new file mode 100644 index 0000000000..cde5b4d74c --- /dev/null +++ b/support/dtotimespec.c @@ -0,0 +1,50 @@ +/* Convert double to timespec. + Copyright (C) 2011-2023 Free Software Foundation, Inc. + This file is part of the GNU C Library and is also part of gnulib. + Patches to this file should be submitted to both projects. + + 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 + . */ + +/* Convert the double value SEC to a struct timespec. Round toward + positive infinity. On overflow, return an extremal value. */ + +#include +#include + +struct timespec +dtotimespec (double sec) +{ + if (sec <= TYPE_MINIMUM (time_t)) + return make_timespec (TYPE_MINIMUM (time_t), 0); + else if (sec >= 1.0 + TYPE_MAXIMUM (time_t)) + return make_timespec (TYPE_MAXIMUM (time_t), TIMESPEC_HZ - 1); + else + { + time_t s = sec; + double frac = TIMESPEC_HZ * (sec - s); + long ns = frac; + ns += ns < frac; + s += ns / TIMESPEC_HZ; + ns %= TIMESPEC_HZ; + + if (ns < 0) + { + s--; + ns += TIMESPEC_HZ; + } + + return make_timespec (s, ns); + } +} diff --git a/support/shell-container.c b/support/shell-container.c index ffa3378b5e..b1f9e793c1 100644 --- a/support/shell-container.c +++ b/support/shell-container.c @@ -37,6 +37,7 @@ #include #include +#include /* Design considerations @@ -169,6 +170,32 @@ kill_func (char **argv) return 0; } +/* Emulate the "/bin/sleep" command. No suffix support. Options are + ignored. */ +static int +sleep_func (char **argv) +{ + if (argv[0] == NULL) + { + fprintf (stderr, "sleep: missing operand\n"); + return 1; + } + char *endptr = NULL; + double sec = strtod (argv[0], &endptr); + if (endptr == argv[0] || errno == ERANGE || sec < 0) + { + fprintf (stderr, "sleep: invalid time interval '%s'\n", argv[0]); + return 1; + } + struct timespec ts = dtotimespec (sec); + if (nanosleep (&ts, NULL) < 0) + { + fprintf (stderr, "sleep: failed to nanosleep: %s\n", strerror (errno)); + return 1; + } + return 0; +} + /* This is a list of all the built-in commands we understand. */ static struct { const char *name; @@ -179,6 +206,7 @@ static struct { { "cp", copy_func }, { "exit", exit_func }, { "kill", kill_func }, + { "sleep", sleep_func }, { NULL, NULL } }; diff --git a/support/timespec.h b/support/timespec.h index 77b1e4e8d6..9559836d4c 100644 --- a/support/timespec.h +++ b/support/timespec.h @@ -57,6 +57,8 @@ int support_timespec_check_in_range (struct timespec expected, struct timespec observed, double lower_bound, double upper_bound); +struct timespec dtotimespec (double sec) __attribute__((const)); + #else struct timespec __REDIRECT (timespec_add, (struct timespec, struct timespec), timespec_add_time64); @@ -82,6 +84,8 @@ int __REDIRECT (support_timespec_check_in_range, (struct timespec expected, double lower_bound, double upper_bound), support_timespec_check_in_range_time64); + +struct timespec __REDIRECT (dtotimespec, (double sec), dtotimespec_time64); #endif /* Check that the timespec on the left represents a time before the -- cgit 1.4.1