glibc/sysdeps/mach/sleep.c
Samuel Thibault f071795d80 mach: Fix bogus negative return
One can be very unlucky to call time_now first just before a second switch,
and mach_msg sleep just a bit more enough for the second time_now call to
count one second too many (or even more if scheduling is really unlucky).

So we have to protect against returning a bogus negative value in such case.
2024-08-25 03:35:29 +02:00

52 lines
1.7 KiB
C

/* Copyright (C) 1992-2024 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
<https://www.gnu.org/licenses/>. */
#include <signal.h>
#include <time.h>
#include <unistd.h>
#include <mach.h>
#include <sysdep-cancel.h>
/* Make the process sleep for SECONDS seconds, or until a signal arrives
and is not ignored. The function returns the number of seconds less
than SECONDS which it actually slept (zero if it slept the full time).
There is no return value to indicate error, but if `sleep' returns
SECONDS, it probably didn't work. */
unsigned int
__sleep (unsigned int seconds)
{
time_t before, after;
mach_port_t recv;
int cancel_oldtype;
recv = __mach_reply_port ();
before = time_now ();
cancel_oldtype = LIBC_CANCEL_ASYNC();
(void) __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
0, 0, recv, seconds * 1000, MACH_PORT_NULL);
LIBC_CANCEL_RESET (cancel_oldtype);
after = time_now ();
__mach_port_destroy (__mach_task_self (), recv);
if (after - before > seconds)
return 0;
return seconds - (after - before);
}
weak_alias (__sleep, sleep)