procps/proc/sysinfo.c
Jim Warner b4d21c74ac library: correct the procps_pid_length() +1 distortion
Unfortunately, reading that '/proc/sys/kernel/pid_max'
file returns a newline, which we will now account for.

[ also, we should use the existing dedicated buffer ]

Reference(s):
. original 'procps_pid_length' introduction
commit ccb6ae8de1

Signed-off-by: Jim Warner <james.warner@comcast.net>
2016-04-18 19:29:41 +10:00

227 lines
6.1 KiB
C

/*
* File for parsing top-level /proc entities.
* Copyright (C) 1992-1998 by Michael K. Johnson, johnsonm@redhat.com
* Copyright 1998-2003 Albert Cahalan
* June 2003, Fabian Frederick, slab info
*
* 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
*/
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <locale.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include "alloc.h"
#include "version.h"
#include "sysinfo.h" /* include self to verify prototypes */
#include "procps-private.h"
#define BAD_OPEN_MESSAGE \
"Error: /proc must be mounted\n" \
" To mount /proc at boot you need an /etc/fstab line like:\n" \
" proc /proc proc defaults\n" \
" In the meantime, run \"mount proc /proc -t proc\"\n"
#define LOADAVG_FILE "/proc/loadavg"
static int loadavg_fd = -1;
// As of 2.6.24 /proc/meminfo seems to need 888 on 64-bit,
// and would need 1258 if the obsolete fields were there.
// As of 3.13 /proc/vmstat needs 2623,
// and /proc/stat needs 3076.
static char buf[8192];
/* This macro opens filename only if necessary and seeks to 0 so
* that successive calls to the functions are more efficient.
* It also reads the current contents of the file into the global buf.
*/
#define FILE_TO_BUF(filename, fd) do{ \
static int local_n; \
if (fd == -1 && (fd = open(filename, O_RDONLY)) == -1) { \
fputs(BAD_OPEN_MESSAGE, stderr); \
fflush(NULL); \
_exit(102); \
} \
lseek(fd, 0L, SEEK_SET); \
if ((local_n = read(fd, buf, sizeof buf - 1)) < 0) { \
perror(filename); \
fflush(NULL); \
_exit(103); \
} \
buf[local_n] = '\0'; \
}while(0)
/* evals 'x' twice */
#define SET_IF_DESIRED(x,y) do{ if(x) *(x) = (y); }while(0)
/* return minimum of two values */
#define MIN(x,y) ((x) < (y) ? (x) : (y))
/*
* procps_hertz_get:
*
*
* 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.
*
* Returns:
* The discovered or assumed hertz value
*/
PROCPS_EXPORT long procps_hertz_get(void)
{
long hz;
#ifdef _SC_CLK_TCK
if ((hz = sysconf(_SC_CLK_TCK)) > 0)
return hz;
#endif
#ifdef HZ
return(HZ);
#endif
/* Last resort, assume 100 */
return 100;
}
/*
* 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)
{
double avg_1=0, avg_5=0, avg_15=0;
char *savelocale;
int retval=0;
FILE_TO_BUF(LOADAVG_FILE,loadavg_fd);
savelocale = strdup(setlocale(LC_NUMERIC, NULL));
setlocale(LC_NUMERIC, "C");
if (sscanf(buf, "%lf %lf %lf", &avg_1, &avg_5, &avg_15) < 3) {
retval = -ERANGE;
}
setlocale(LC_NUMERIC, savelocale);
free(savelocale);
SET_IF_DESIRED(av1, avg_1);
SET_IF_DESIRED(av5, avg_5);
SET_IF_DESIRED(av15, avg_15);
return retval;
}
static char buff[BUFFSIZE]; /* used in the procedures */
/***********************************************************************/
static void crash(const char *filename) {
perror(filename);
exit(EXIT_FAILURE);
}
/////////////////////////////////////////////////////////////////////////////
// based on Fabian Frederick's /proc/slabinfo parser
unsigned int getslabinfo (struct slab_cache **slab){
FILE* fd;
int cSlab = 0;
buff[BUFFSIZE-1] = 0;
*slab = NULL;
fd = fopen("/proc/slabinfo", "rb");
if(!fd) crash("/proc/slabinfo");
while (fgets(buff,BUFFSIZE-1,fd)){
if(!memcmp("slabinfo - version:",buff,19)) continue; // skip header
if(*buff == '#') continue; // skip comments
(*slab) = xrealloc(*slab, (cSlab+1)*sizeof(struct slab_cache));
sscanf(buff, "%47s %u %u %u %u", // allow 47; max seen is 24
(*slab)[cSlab].name,
&(*slab)[cSlab].active_objs,
&(*slab)[cSlab].num_objs,
&(*slab)[cSlab].objsize,
&(*slab)[cSlab].objperslab
) ;
cSlab++;
}
fclose(fd);
return cSlab;
}
#define PROCFS_PID_MAX "/proc/sys/kernel/pid_max"
#define DEFAULT_PID_LENGTH 5
/*
* 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];
char *endp;
unsigned long int max_pid;
static 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;
}
///////////////////////////////////////////////////////////////////////////
/* procps_cpu_count:
*
* Returns the number of CPUs that are currently online.
*
*/
long procps_cpu_count(void)
{
long cpus=1;
cpus = sysconf(_SC_NPROCESSORS_ONLN);
if (cpus < 1)
return 1;
return cpus;
}