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/* Get file-specific information about a file. Linux version.
Copyright (C) 2003, 2004 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <fcntl.h>
#include <sysdep.h>
#include <time.h>
#include <unistd.h>
static long int posix_sysconf (int name);
/* Define this first, so it can be inlined. */
#define __sysconf static posix_sysconf
#include <sysdeps/posix/sysconf.c>
/* Get the value of the system variable NAME. */
long int
__sysconf (int name)
{
switch (name)
{
#ifdef __NR_clock_getres
case _SC_MONOTONIC_CLOCK:
/* Check using the clock_getres system call. */
{
struct timespec ts;
INTERNAL_SYSCALL_DECL (err);
int r;
r = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
return INTERNAL_SYSCALL_ERROR_P (r, err) ? -1 : 1;
}
#endif
case _SC_NGROUPS_MAX:
{
/* Try to read the information from the /proc/sys/kernel/ngroups_max
file. */
int fd = __open_nocancel ("/proc/sys/kernel/ngroups_max", O_RDONLY);
if (fd != -1)
{
/* This is more than enough, the file contains a single
integer. */
char buf[32];
long int res = -1l;
ssize_t n = __read_nocancel (fd, buf, sizeof (buf) - 1);
if (n > 0)
{
/* Terminate the string. */
buf[n] = '\0';
char *endp;
res = strtol (buf, &endp, 10);
if (endp == buf || (*endp != '\0' && *endp != '\n'))
res = -1l;
}
__close_nocancel (fd);
if (res != -1)
return res;
}
}
break;
default:
break;
}
return posix_sysconf (name);
}
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