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364 lines
9.1 KiB
C
364 lines
9.1 KiB
C
/* Determine various system internal values, Linux version.
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Copyright (C) 1996-2003,2006,2007,2009,2010,2011 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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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 <alloca.h>
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#include <assert.h>
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#include <ctype.h>
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <mntent.h>
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#include <paths.h>
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#include <stdio.h>
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#include <stdio_ext.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/sysinfo.h>
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#include <atomic.h>
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#include <not-cancel.h>
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#include <kernel-features.h>
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/* How we can determine the number of available processors depends on
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the configuration. There is currently (as of version 2.0.21) no
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system call to determine the number. It is planned for the 2.1.x
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series to add this, though.
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One possibility to implement it for systems using Linux 2.0 is to
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examine the pseudo file /proc/cpuinfo. Here we have one entry for
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each processor.
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But not all systems have support for the /proc filesystem. If it
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is not available we simply return 1 since there is no way. */
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/* Other architectures use different formats for /proc/cpuinfo. This
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provides a hook for alternative parsers. */
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#ifndef GET_NPROCS_PARSER
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# define GET_NPROCS_PARSER(FD, BUFFER, CP, RE, BUFFER_END, RESULT) \
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do \
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{ \
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(RESULT) = 0; \
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/* Read all lines and count the lines starting with the string \
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"processor". We don't have to fear extremely long lines since \
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the kernel will not generate them. 8192 bytes are really \
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enough. */ \
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char *l; \
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while ((l = next_line (FD, BUFFER, &CP, &RE, BUFFER_END)) != NULL) \
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if (strncmp (l, "processor", 9) == 0) \
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++(RESULT); \
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} \
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while (0)
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#endif
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static char *
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next_line (int fd, char *const buffer, char **cp, char **re,
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char *const buffer_end)
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{
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char *res = *cp;
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char *nl = memchr (*cp, '\n', *re - *cp);
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if (nl == NULL)
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{
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if (*cp != buffer)
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{
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if (*re == buffer_end)
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{
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memmove (buffer, *cp, *re - *cp);
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*re = buffer + (*re - *cp);
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*cp = buffer;
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ssize_t n = read_not_cancel (fd, *re, buffer_end - *re);
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if (n < 0)
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return NULL;
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*re += n;
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nl = memchr (*cp, '\n', *re - *cp);
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while (nl == NULL && *re == buffer_end)
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{
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/* Truncate too long lines. */
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*re = buffer + 3 * (buffer_end - buffer) / 4;
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n = read_not_cancel (fd, *re, buffer_end - *re);
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if (n < 0)
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return NULL;
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nl = memchr (*re, '\n', n);
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**re = '\n';
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*re += n;
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}
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}
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else
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nl = memchr (*cp, '\n', *re - *cp);
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res = *cp;
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}
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if (nl == NULL)
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nl = *re - 1;
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}
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*cp = nl + 1;
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assert (*cp <= *re);
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return res == *re ? NULL : res;
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}
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int
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__get_nprocs ()
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{
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static int cached_result;
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static time_t timestamp;
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time_t now = time (NULL);
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time_t prev = timestamp;
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atomic_read_barrier ();
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if (now == prev)
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return cached_result;
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/* XXX Here will come a test for the new system call. */
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const size_t buffer_size = __libc_use_alloca (8192) ? 8192 : 512;
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char *buffer = alloca (buffer_size);
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char *buffer_end = buffer + buffer_size;
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char *cp = buffer_end;
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char *re = buffer_end;
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#ifdef O_CLOEXEC
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const int flags = O_RDONLY | O_CLOEXEC;
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#else
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const int flags = O_RDONLY;
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#endif
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int fd = open_not_cancel_2 ("/sys/devices/system/cpu/online", flags);
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char *l;
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int result = 0;
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if (fd != -1)
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{
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l = next_line (fd, buffer, &cp, &re, buffer_end);
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if (l != NULL)
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do
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{
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char *endp;
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unsigned long int n = strtoul (l, &endp, 10);
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if (l == endp)
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{
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result = 0;
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break;
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}
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unsigned long int m = n;
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if (*endp == '-')
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{
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l = endp + 1;
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m = strtoul (l, &endp, 10);
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if (l == endp)
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{
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result = 0;
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break;
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}
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}
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result += m - n + 1;
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l = endp;
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while (l < re && isspace (*l))
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++l;
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}
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while (l < re);
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close_not_cancel_no_status (fd);
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if (result > 0)
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goto out;
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}
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cp = buffer_end;
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re = buffer_end;
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result = 1;
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/* The /proc/stat format is more uniform, use it by default. */
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fd = open_not_cancel_2 ("/proc/stat", flags);
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if (fd != -1)
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{
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result = 0;
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while ((l = next_line (fd, buffer, &cp, &re, buffer_end)) != NULL)
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/* The current format of /proc/stat has all the cpu* entries
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at the front. We assume here that stays this way. */
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if (strncmp (l, "cpu", 3) != 0)
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break;
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else if (isdigit (l[3]))
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++result;
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close_not_cancel_no_status (fd);
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}
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else
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{
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fd = open_not_cancel_2 ("/proc/cpuinfo", flags);
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if (fd != -1)
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{
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GET_NPROCS_PARSER (fd, buffer, cp, re, buffer_end, result);
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close_not_cancel_no_status (fd);
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}
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}
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out:
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cached_result = result;
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atomic_write_barrier ();
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timestamp = now;
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return result;
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}
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weak_alias (__get_nprocs, get_nprocs)
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/* On some architectures it is possible to distinguish between configured
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and active cpus. */
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int
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__get_nprocs_conf ()
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{
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/* XXX Here will come a test for the new system call. */
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/* Try to use the sysfs filesystem. It has actual information about
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online processors. */
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DIR *dir = __opendir ("/sys/devices/system/cpu");
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if (dir != NULL)
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{
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int count = 0;
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struct dirent64 *d;
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while ((d = __readdir64 (dir)) != NULL)
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/* NB: the sysfs has d_type support. */
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if (d->d_type == DT_DIR && strncmp (d->d_name, "cpu", 3) == 0)
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{
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char *endp;
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unsigned long int nr = strtoul (d->d_name + 3, &endp, 10);
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if (nr != ULONG_MAX && endp != d->d_name + 3 && *endp == '\0')
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++count;
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}
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__closedir (dir);
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return count;
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}
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int result = 1;
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#ifdef GET_NPROCS_CONF_PARSER
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/* If we haven't found an appropriate entry return 1. */
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FILE *fp = fopen ("/proc/cpuinfo", "rce");
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if (fp != NULL)
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{
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char buffer[8192];
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/* No threads use this stream. */
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__fsetlocking (fp, FSETLOCKING_BYCALLER);
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GET_NPROCS_CONF_PARSER (fp, buffer, result);
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fclose (fp);
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}
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#else
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result = __get_nprocs ();
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#endif
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return result;
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}
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weak_alias (__get_nprocs_conf, get_nprocs_conf)
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/* General function to get information about memory status from proc
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filesystem. */
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static long int
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internal_function
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phys_pages_info (const char *format)
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{
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char buffer[8192];
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long int result = -1;
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/* If we haven't found an appropriate entry return 1. */
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FILE *fp = fopen ("/proc/meminfo", "rce");
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if (fp != NULL)
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{
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/* No threads use this stream. */
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__fsetlocking (fp, FSETLOCKING_BYCALLER);
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result = 0;
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/* Read all lines and count the lines starting with the
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string "processor". We don't have to fear extremely long
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lines since the kernel will not generate them. 8192
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bytes are really enough. */
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while (fgets_unlocked (buffer, sizeof buffer, fp) != NULL)
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if (sscanf (buffer, format, &result) == 1)
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{
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result /= (__getpagesize () / 1024);
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break;
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}
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fclose (fp);
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}
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if (result == -1)
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/* We cannot get the needed value: signal an error. */
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__set_errno (ENOSYS);
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return result;
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}
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/* Return the number of pages of physical memory in the system. There
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is currently (as of version 2.0.21) no system call to determine the
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number. It is planned for the 2.1.x series to add this, though.
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One possibility to implement it for systems using Linux 2.0 is to
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examine the pseudo file /proc/cpuinfo. Here we have one entry for
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each processor.
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But not all systems have support for the /proc filesystem. If it
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is not available we return -1 as an error signal. */
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long int
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__get_phys_pages ()
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{
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/* XXX Here will come a test for the new system call. */
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return phys_pages_info ("MemTotal: %ld kB");
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}
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weak_alias (__get_phys_pages, get_phys_pages)
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/* Return the number of available pages of physical memory in the
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system. There is currently (as of version 2.0.21) no system call
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to determine the number. It is planned for the 2.1.x series to add
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this, though.
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One possibility to implement it for systems using Linux 2.0 is to
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examine the pseudo file /proc/cpuinfo. Here we have one entry for
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each processor.
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But not all systems have support for the /proc filesystem. If it
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is not available we return -1 as an error signal. */
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long int
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__get_avphys_pages ()
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{
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/* XXX Here will come a test for the new system call. */
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return phys_pages_info ("MemFree: %ld kB");
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}
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weak_alias (__get_avphys_pages, get_avphys_pages)
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