glibc/sysdeps/unix/sysv/linux/times.c

61 lines
2.1 KiB
C

/* Copyright (C) 2008-2016 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
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <sys/times.h>
#include <sysdep.h>
clock_t
__times (struct tms *buf)
{
INTERNAL_SYSCALL_DECL (err);
clock_t ret = INTERNAL_SYSCALL (times, err, 1, buf);
if (INTERNAL_SYSCALL_ERROR_P (ret, err)
&& __builtin_expect (INTERNAL_SYSCALL_ERRNO (ret, err) == EFAULT, 0)
&& buf)
{
/* This might be an error or not. For architectures which have
no separate return value and error indicators we cannot
distinguish a return value of -1 from an error. Do it the
hard way. We crash applications which pass in an invalid
non-NULL BUF pointer. Linux allows BUF to be NULL. */
#define touch(v) \
do { \
clock_t temp = v; \
asm volatile ("" : "+r" (temp)); \
v = temp; \
} while (0)
touch (buf->tms_utime);
touch (buf->tms_stime);
touch (buf->tms_cutime);
touch (buf->tms_cstime);
/* If we come here the memory is valid (or BUF is NULL, which is
a valid condition for the kernel syscall) and the kernel did not
return an EFAULT error. Return the value given by the kernel. */
}
/* Return value (clock_t) -1 signals an error, but if there wasn't any,
return the following value. */
if (ret == (clock_t) -1)
return (clock_t) 0;
return ret;
}
weak_alias (__times, times)