1 /* Get file-specific information about a file. Linux version.
2 Copyright (C) 2003-2014 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
25 #include <sys/resource.h>
26 #include <not-cancel.h>
29 /* Legacy value of ARG_MAX. The macro is now not defined since the
30 actual value varies based on the stack size. */
31 #define legacy_ARG_MAX 131072
34 static long int posix_sysconf (int name);
39 has_cpuclock (int name)
41 # if defined __NR_clock_getres || HP_TIMING_AVAIL
42 /* If we have HP_TIMING, we will fall back on that if the system
43 call does not work, so we support it either way. */
45 /* Check using the clock_getres system call. */
47 INTERNAL_SYSCALL_DECL (err);
48 int r = INTERNAL_SYSCALL (clock_getres, err, 2,
50 ? CLOCK_PROCESS_CPUTIME_ID
51 : CLOCK_THREAD_CPUTIME_ID),
53 if (INTERNAL_SYSCALL_ERROR_P (r, err))
56 return _POSIX_VERSION;
61 # define HAS_CPUCLOCK(name) has_cpuclock (name)
65 /* Get the value of the system variable NAME. */
69 const char *procfname = NULL;
74 #ifdef __NR_clock_getres
75 case _SC_MONOTONIC_CLOCK:
76 /* Check using the clock_getres system call. */
79 INTERNAL_SYSCALL_DECL (err);
81 r = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
82 return INTERNAL_SYSCALL_ERROR_P (r, err) ? -1 : _POSIX_VERSION;
87 case _SC_THREAD_CPUTIME:
88 return HAS_CPUCLOCK (name);
91 /* Use getrlimit to get the stack limit. */
92 if (__getrlimit (RLIMIT_STACK, &rlimit) == 0)
93 return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4);
95 return legacy_ARG_MAX;
98 /* Try to read the information from the /proc/sys/kernel/ngroups_max
100 procfname = "/proc/sys/kernel/ngroups_max";
103 case _SC_SIGQUEUE_MAX:
104 if (__getrlimit (RLIMIT_SIGPENDING, &rlimit) == 0)
105 return rlimit.rlim_cur;
107 /* The /proc/sys/kernel/rtsig-max file contains the answer. */
108 procfname = "/proc/sys/kernel/rtsig-max";
115 if (procfname != NULL)
117 int fd = open_not_cancel_2 (procfname, O_RDONLY);
120 /* This is more than enough, the file contains a single integer. */
123 n = TEMP_FAILURE_RETRY (read_not_cancel (fd, buf, sizeof (buf) - 1));
124 close_not_cancel_no_status (fd);
128 /* Terminate the string. */
132 long int res = strtol (buf, &endp, 10);
133 if (endp != buf && (*endp == '\0' || *endp == '\n'))
139 return posix_sysconf (name);
142 /* Now the POSIX version. */
144 #define __sysconf static posix_sysconf
145 #include <sysdeps/posix/sysconf.c>