298 lines
8.6 KiB
C
298 lines
8.6 KiB
C
/* Determine various system internal values, Linux version.
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Copyright (C) 1996,1997,1998,1999,2000,2001 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <alloca.h>
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#include <assert.h>
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#include <errno.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 <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 <atomicity.h>
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/* The default value for the /proc filesystem mount point. */
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static const char path_proc[] = "/proc";
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/* Actual mount point of /proc filesystem. */
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static char *mount_proc;
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/* Determine the path to the /proc filesystem if available. */
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static const char *
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internal_function
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get_proc_path (char *buffer, size_t bufsize)
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{
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struct mntent mount_point;
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struct mntent *entry;
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char *result = NULL;
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char *copy_result;
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FILE *fp;
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/* First find the mount point of the proc filesystem. */
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fp = __setmntent (_PATH_MOUNTED, "r");
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if (fp == NULL)
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fp = __setmntent (_PATH_MNTTAB, "r");
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if (fp != NULL)
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{
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while ((entry = __getmntent_r (fp, &mount_point, buffer, bufsize))
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!= NULL)
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if (strcmp (mount_point.mnt_type, "proc") == 0)
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{
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result = mount_point.mnt_dir;
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break;
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}
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__endmntent (fp);
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}
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/* If we haven't found anything this is generally a bad sign but we
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handle it gracefully. We return what is hopefully the right
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answer (/proc) but we don't remember this. This will enable
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programs which started before the system is fully running to
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adjust themselves. */
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if (result == NULL)
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return path_proc;
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/* Make a copy we can keep around. */
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copy_result = __strdup (result);
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if (copy_result == NULL)
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return result;
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/* Now store the copied value. But do it atomically. */
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assert (sizeof (long int) == sizeof (void *__unbounded));
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if (compare_and_swap ((long int *) &mount_proc, (long int) 0,
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(long int) copy_result) == 0)
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/* Replacing the value failed. This means another thread was
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faster and we don't need the copy anymore. */
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free (copy_result);
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#if __BOUNDED_POINTERS__
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else
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{
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/* compare_and_swap only copied the pointer value, so we must
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now copy the bounds as well. */
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__ptrlow (mount_proc) = __ptrlow (copy_result);
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__ptrhigh (mount_proc) = __ptrhigh (copy_result);
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}
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#endif
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return mount_proc;
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}
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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(FP, BUFFER, 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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while (fgets_unlocked (BUFFER, sizeof (BUFFER), FP) != NULL) \
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if (strncmp (BUFFER, "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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int
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__get_nprocs ()
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{
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FILE *fp;
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char buffer[8192];
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const char *proc_path;
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int result = 1;
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/* XXX Here will come a test for the new system call. */
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/* Get mount point of proc filesystem. */
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proc_path = get_proc_path (buffer, sizeof buffer);
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/* If we haven't found an appropriate entry return 1. */
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if (proc_path != NULL)
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{
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char *proc_cpuinfo = alloca (strlen (proc_path) + sizeof ("/cpuinfo"));
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__stpcpy (__stpcpy (proc_cpuinfo, proc_path), "/cpuinfo");
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fp = fopen (proc_cpuinfo, "r");
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if (fp != NULL)
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{
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GET_NPROCS_PARSER (fp, buffer, result);
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fclose (fp);
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}
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}
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return result;
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}
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weak_alias (__get_nprocs, get_nprocs)
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#ifdef GET_NPROCS_CONF_PARSER
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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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FILE *fp;
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char buffer[8192];
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const char *proc_path;
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int result = 1;
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/* XXX Here will come a test for the new system call. */
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/* Get mount point of proc filesystem. */
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proc_path = get_proc_path (buffer, sizeof buffer);
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/* If we haven't found an appropriate entry return 1. */
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if (proc_path != NULL)
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{
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char *proc_cpuinfo = alloca (strlen (proc_path) + sizeof ("/cpuinfo"));
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__stpcpy (__stpcpy (proc_cpuinfo, proc_path), "/cpuinfo");
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fp = fopen (proc_cpuinfo, "r");
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if (fp != NULL)
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{
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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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}
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return result;
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}
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#else
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/* As far as I know Linux has no separate numbers for configured and
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available processors. So make the `get_nprocs_conf' function an
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alias. */
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strong_alias (__get_nprocs, __get_nprocs_conf)
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#endif
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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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FILE *fp;
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char buffer[8192];
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const char *proc_path;
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long int result = -1;
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/* Get mount point of proc filesystem. */
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proc_path = get_proc_path (buffer, sizeof buffer);
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/* If we haven't found an appropriate entry return 1. */
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if (proc_path != NULL)
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{
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char *proc_meminfo = alloca (strlen (proc_path) + sizeof ("/meminfo"));
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__stpcpy (__stpcpy (proc_meminfo, proc_path), "/meminfo");
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fp = fopen (proc_meminfo, "r");
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if (fp != NULL)
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{
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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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}
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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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static void
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free_mem (void)
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{
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free (mount_proc);
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}
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text_set_element (__libc_subfreeres, free_mem);
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