glibc/support/dtotimespec.c
Adam Yi 78ab913eab 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
5fb7fc9635 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 <ayi@janestreet.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit 436a604b7d)
2023-04-28 13:21:20 +02:00

51 lines
1.6 KiB
C

/* 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
<https://www.gnu.org/licenses/>. */
/* Convert the double value SEC to a struct timespec. Round toward
positive infinity. On overflow, return an extremal value. */
#include <support/timespec.h>
#include <intprops.h>
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);
}
}