diff options
Diffstat (limited to 'REORG.TODO/sysdeps/unix/sysv/linux/sysconf.c')
| -rw-r--r-- | REORG.TODO/sysdeps/unix/sysv/linux/sysconf.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/sysconf.c b/REORG.TODO/sysdeps/unix/sysv/linux/sysconf.c new file mode 100644 index 0000000000..db20977cb8 --- /dev/null +++ b/REORG.TODO/sysdeps/unix/sysv/linux/sysconf.c @@ -0,0 +1,146 @@ +/* Get file-specific information about a file. Linux version. + Copyright (C) 2003-2017 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 <fcntl.h> +#include <stdlib.h> +#include <sysdep.h> +#include <time.h> +#include <unistd.h> +#include <sys/resource.h> +#include <sys/param.h> +#include <not-cancel.h> +#include <ldsodefs.h> + +/* Legacy value of ARG_MAX. The macro is now not defined since the + actual value varies based on the stack size. */ +#define legacy_ARG_MAX 131072 + + +static long int posix_sysconf (int name); + + +#ifndef HAS_CPUCLOCK +static long int +has_cpuclock (int name) +{ +# if defined __NR_clock_getres || HP_TIMING_AVAIL + /* If we have HP_TIMING, we will fall back on that if the system + call does not work, so we support it either way. */ +# if !HP_TIMING_AVAIL + /* Check using the clock_getres system call. */ + struct timespec ts; + INTERNAL_SYSCALL_DECL (err); + int r = INTERNAL_SYSCALL (clock_getres, err, 2, + (name == _SC_CPUTIME + ? CLOCK_PROCESS_CPUTIME_ID + : CLOCK_THREAD_CPUTIME_ID), + &ts); + if (INTERNAL_SYSCALL_ERROR_P (r, err)) + return -1; +# endif + return _POSIX_VERSION; +# else + return -1; +# endif +} +# define HAS_CPUCLOCK(name) has_cpuclock (name) +#endif + + +/* Get the value of the system variable NAME. */ +long int +__sysconf (int name) +{ + const char *procfname = NULL; + + switch (name) + { + struct rlimit rlimit; +#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 : _POSIX_VERSION; + } +#endif + + case _SC_CPUTIME: + case _SC_THREAD_CPUTIME: + return HAS_CPUCLOCK (name); + + case _SC_ARG_MAX: + /* Use getrlimit to get the stack limit. */ + if (__getrlimit (RLIMIT_STACK, &rlimit) == 0) + return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4); + + return legacy_ARG_MAX; + + case _SC_NGROUPS_MAX: + /* Try to read the information from the /proc/sys/kernel/ngroups_max + file. */ + procfname = "/proc/sys/kernel/ngroups_max"; + break; + + case _SC_SIGQUEUE_MAX: + if (__getrlimit (RLIMIT_SIGPENDING, &rlimit) == 0) + return rlimit.rlim_cur; + + /* The /proc/sys/kernel/rtsig-max file contains the answer. */ + procfname = "/proc/sys/kernel/rtsig-max"; + break; + + default: + break; + } + + if (procfname != NULL) + { + int fd = open_not_cancel_2 (procfname, O_RDONLY); + if (fd != -1) + { + /* This is more than enough, the file contains a single integer. */ + char buf[32]; + ssize_t n; + n = TEMP_FAILURE_RETRY (read_not_cancel (fd, buf, sizeof (buf) - 1)); + close_not_cancel_no_status (fd); + + if (n > 0) + { + /* Terminate the string. */ + buf[n] = '\0'; + + char *endp; + long int res = strtol (buf, &endp, 10); + if (endp != buf && (*endp == '\0' || *endp == '\n')) + return res; + } + } + } + + return posix_sysconf (name); +} + +/* Now the POSIX version. */ +#undef __sysconf +#define __sysconf static posix_sysconf +#include <sysdeps/posix/sysconf.c> |