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77b6f55347
The Linux 3.2 clock_getres kernel code (kernel/posix-cpu-timers.c) issued for clock_getres CLOCK_PROCESS_CPUTIME_ID (process_cpu_clock_getres) and CLOCK_THREAD_CPUTIME_ID (thread_cpu_clock_getres) call posix_cpu_clock_getres. And it fails on check_clock only if an invalid clock is used (not the case) or if we pass an invalid the pid/tid in 29 msb of clock_id (not the case either). This patch assumes that clock_getres syscall always support CLOCK_PROCESS_CPUTIME_ID and CLOCK_THREAD_CPUTIME_ID, so there is no need to fallback to hp-timing support for _SC_MONOTONIC_CLOCK neither to issue the syscall to certify the clock_id is supported bt the kernel. This allows simplify the sysconf support to always use the syscall. it also removes ia64 itc drift check and assume kernel handles it correctly. Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. * sysdeps/unix/sysv/linux/ia64/has_cpuclock.c: Remove file. * sysdeps/unix/sysv/linux/ia64/sysconf.c: Likewise. * sysdeps/unix/sysv/linux/sysconf.c (has_cpuclock): Remove function. (__sysconf): Assume kernel support for _SC_MONOTONIC_CLOCK, _SC_CPUTIME, and _SC_THREAD_CPUTIME.
113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
/* Get file-specific information about a file. Linux version.
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Copyright (C) 2003-2019 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <sysdep.h>
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#include <time.h>
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#include <unistd.h>
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#include <sys/resource.h>
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#include <sys/param.h>
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#include <not-cancel.h>
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#include <ldsodefs.h>
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/* Legacy value of ARG_MAX. The macro is now not defined since the
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actual value varies based on the stack size. */
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#define legacy_ARG_MAX 131072
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static long int posix_sysconf (int name);
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/* Get the value of the system variable NAME. */
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long int
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__sysconf (int name)
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{
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const char *procfname = NULL;
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switch (name)
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{
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case _SC_MONOTONIC_CLOCK:
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case _SC_CPUTIME:
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case _SC_THREAD_CPUTIME:
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return _POSIX_VERSION;
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case _SC_ARG_MAX:
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{
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struct rlimit rlimit;
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/* Use getrlimit to get the stack limit. */
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if (__getrlimit (RLIMIT_STACK, &rlimit) == 0)
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return MAX (legacy_ARG_MAX, rlimit.rlim_cur / 4);
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return legacy_ARG_MAX;
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}
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case _SC_NGROUPS_MAX:
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/* Try to read the information from the /proc/sys/kernel/ngroups_max
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file. */
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procfname = "/proc/sys/kernel/ngroups_max";
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break;
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case _SC_SIGQUEUE_MAX:
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{
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struct rlimit rlimit;
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if (__getrlimit (RLIMIT_SIGPENDING, &rlimit) == 0)
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return rlimit.rlim_cur;
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/* The /proc/sys/kernel/rtsig-max file contains the answer. */
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procfname = "/proc/sys/kernel/rtsig-max";
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}
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break;
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default:
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break;
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}
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if (procfname != NULL)
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{
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int fd = __open_nocancel (procfname, O_RDONLY);
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if (fd != -1)
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{
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/* This is more than enough, the file contains a single integer. */
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char buf[32];
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ssize_t n;
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n = TEMP_FAILURE_RETRY (__read_nocancel (fd, buf, sizeof (buf) - 1));
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__close_nocancel_nostatus (fd);
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if (n > 0)
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{
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/* Terminate the string. */
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buf[n] = '\0';
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char *endp;
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long int res = strtol (buf, &endp, 10);
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if (endp != buf && (*endp == '\0' || *endp == '\n'))
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return res;
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}
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}
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}
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return posix_sysconf (name);
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}
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/* Now the POSIX version. */
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#undef __sysconf
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#define __sysconf static posix_sysconf
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#include <sysdeps/posix/sysconf.c>
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