procps/library/sysinfo.c

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/*
* File for parsing top-level /proc entities.
*
* Copyright © 2011-2023 Jim Warner <james.warner@comcast.net>
* Copyright © 2011-2023 Craig Small <csmall@dropbear.xyz>
* Copyright © 1998-2008 Albert Cahalan
* Copyright © 1992-1998 Michael K. Johnson <johnsonm@redhat.com>
*
* This 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.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
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#include <stdbool.h>
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <locale.h>
#include <errno.h>
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#include <unistd.h>
#include <fcntl.h>
#ifdef __CYGWIN__
#include <sys/param.h>
#endif
#include "misc.h"
#include "procps-private.h"
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#define LOADAVG_FILE "/proc/loadavg"
/* evals 'x' twice */
#define SET_IF_DESIRED(x,y) do{ if(x) *(x) = (y); }while(0)
/* return minimum of two values */
#ifndef __CYGWIN__
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#endif
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/*
* procps_hertz_get:
*
*
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* Some values in /proc are expressed in units of 1/HZ seconds, where HZ
* is the kernel clock tick rate. One of these units is called a jiffy.
* The HZ value used in the kernel may vary according to hacker desire.
*
* On some architectures, the kernel provides an ELF note to indicate
* HZ.
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*
* Returns:
* The discovered or assumed hertz value
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*/
PROCPS_EXPORT long procps_hertz_get(void)
{
long hz;
#ifdef _SC_CLK_TCK
if ((hz = sysconf(_SC_CLK_TCK)) > 0)
return hz;
#endif
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#ifdef HZ
return(HZ);
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#endif
/* Last resort, assume 100 */
return 100;
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}
/*
* procps_loadavg:
* @av1: location to store 1 minute load average
* @av5: location to store 5 minute load average
* @av15: location to store 15 minute load average
*
* Find the 1,5 and 15 minute load average of the system
*
* Returns: 0 on success <0 on error
*/
PROCPS_EXPORT int procps_loadavg(
double *restrict av1,
double *restrict av5,
double *restrict av15)
{
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double avg_1=0, avg_5=0, avg_15=0;
locale_t tmplocale;
int retval=0;
FILE *fp;
if ((fp = fopen(LOADAVG_FILE, "r")) == NULL)
return -errno;
tmplocale = newlocale(LC_NUMERIC_MASK, "C", (locale_t)0);
uselocale(tmplocale);
if (fscanf(fp, "%lf %lf %lf", &avg_1, &avg_5, &avg_15) < 3)
retval = -ERANGE;
fclose(fp);
uselocale(LC_GLOBAL_LOCALE);
freelocale(tmplocale);
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SET_IF_DESIRED(av1, avg_1);
SET_IF_DESIRED(av5, avg_5);
SET_IF_DESIRED(av15, avg_15);
return retval;
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}
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/////////////////////////////////////////////////////////////////////////////
#define PROCFS_PID_MAX "/proc/sys/kernel/pid_max"
#define DEFAULT_PID_LENGTH 5
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/*
* procps_pid_length
*
* Return the length of the maximum possible pid.
*
* Returns either the strlen of PROCFS_PID_MAX or the
* best-guess DEFAULT_PID_LENGTH
*/
PROCPS_EXPORT unsigned int procps_pid_length(void)
{
FILE *fp;
char pidbuf[24];
static __thread int pid_length=0;
if (pid_length)
return pid_length;
pid_length = DEFAULT_PID_LENGTH;
if ((fp = fopen(PROCFS_PID_MAX, "r")) != NULL) {
if (fgets(pidbuf, sizeof(pidbuf), fp) != NULL) {
pid_length = strlen(pidbuf);
if (pidbuf[pid_length-1] == '\n')
--pid_length;
}
fclose(fp);
}
return pid_length;
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}
///////////////////////////////////////////////////////////////////////////
/* procps_cpu_count:
*
* Returns the number of CPUs that are currently online.
*
*/
long procps_cpu_count(void)
{
long cpus;
cpus = sysconf(_SC_NPROCESSORS_ONLN);
if (cpus < 1)
return 1;
return cpus;
}