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procps/proc/sysinfo.c

352 lines
12 KiB
C
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/***********************************************************************\
* Copyright (C) 1992-1998 by Michael K. Johnson, johnsonm@redhat.com *
* *
* This file is placed under the conditions of the GNU Library *
* General Public License, version 2, or any later version. *
* See file COPYING for information on distribution conditions. *
\***********************************************************************/
/* File for parsing top-level /proc entities. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <locale.h>
#include <unistd.h>
#include <fcntl.h>
#include "version.h"
#include "sysinfo.h" /* include self to verify prototypes */
#ifndef HZ
#include <netinet/in.h> /* htons */
#endif
long smp_num_cpus; /* number of CPUs */
#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, mount /proc /proc -t proc\n"
#define STAT_FILE "/proc/stat"
static int stat_fd = -1;
#define UPTIME_FILE "/proc/uptime"
static int uptime_fd = -1;
#define LOADAVG_FILE "/proc/loadavg"
static int loadavg_fd = -1;
#define MEMINFO_FILE "/proc/meminfo"
static int meminfo_fd = -1;
static char buf[1024];
/* 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) { \
fprintf(stderr, BAD_OPEN_MESSAGE); \
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)
/***********************************************************************/
int uptime(double *uptime_secs, double *idle_secs) {
double up=0, idle=0;
char *savelocale;
FILE_TO_BUF(UPTIME_FILE,uptime_fd);
savelocale = setlocale(LC_NUMERIC, NULL);
setlocale(LC_NUMERIC,"C");
if (sscanf(buf, "%lf %lf", &up, &idle) < 2) {
setlocale(LC_NUMERIC,savelocale);
fprintf(stderr, "bad data in " UPTIME_FILE "\n");
return 0;
}
setlocale(LC_NUMERIC,savelocale);
SET_IF_DESIRED(uptime_secs, up);
SET_IF_DESIRED(idle_secs, idle);
return up; /* assume never be zero seconds in practice */
}
/***********************************************************************
* 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.
* According to Linus Torvalds, this is not true. He considers the values
* in /proc as being in architecture-dependant units that have no relation
* to the kernel clock tick rate. Examination of the kernel source code
* reveals that opinion as wishful thinking.
*
* In any case, we need the HZ constant as used in /proc. (the real HZ value
* may differ, but we don't care) There are several ways we could get HZ:
*
* 1. Include the kernel header file. If it changes, recompile this library.
* 2. Use the sysconf() function. When HZ changes, recompile the C library!
* 3. Ask the kernel. This is obviously correct...
*
* Linus Torvalds won't let us ask the kernel, because he thinks we should
* not know the HZ value. Oh well, we don't have to listen to him.
* Someone smuggled out the HZ value. :-)
*
* This code should work fine, even if Linus fixes the kernel to match his
* stated behavior. The code only fails in case of a partial conversion.
*
* Recent update: on some architectures, the 2.4 kernel provides an
* ELF note to indicate HZ. This may be for ARM or user-mode Linux
* support. This ought to be investigated. Note that sysconf() is still
* unreliable, because it doesn't return an error code when it is
* used with a kernel that doesn't support the ELF note. On some other
* architectures there may be a system call or sysctl() that will work.
*/
unsigned long long Hertz;
static void init_Hertz_value(void) __attribute__((constructor));
static void init_Hertz_value(void){
unsigned long long user_j, nice_j, sys_j, other_j; /* jiffies (clock ticks) */
double up_1, up_2, seconds;
unsigned long long jiffies;
unsigned h;
char *savelocale;
smp_num_cpus = sysconf(_SC_NPROCESSORS_CONF);
if(smp_num_cpus<1) smp_num_cpus=1;
savelocale = setlocale(LC_NUMERIC, NULL);
setlocale(LC_NUMERIC, "C");
do{
FILE_TO_BUF(UPTIME_FILE,uptime_fd); sscanf(buf, "%lf", &up_1);
/* uptime(&up_1, NULL); */
FILE_TO_BUF(STAT_FILE,stat_fd);
sscanf(buf, "cpu %Lu %Lu %Lu %Lu", &user_j, &nice_j, &sys_j, &other_j);
FILE_TO_BUF(UPTIME_FILE,uptime_fd); sscanf(buf, "%lf", &up_2);
/* uptime(&up_2, NULL); */
} while((long long)( (up_2-up_1)*1000.0/up_1 )); /* want under 0.1% error */
setlocale(LC_NUMERIC, savelocale);
jiffies = user_j + nice_j + sys_j + other_j;
seconds = (up_1 + up_2) / 2;
h = (unsigned)( (double)jiffies/seconds/smp_num_cpus );
/* actual values used by 2.4 kernels: 32 64 100 128 1000 1024 1200 */
switch(h){
case 9 ... 11 : Hertz = 10; break; /* S/390 (sometimes) */
case 18 ... 22 : Hertz = 20; break; /* user-mode Linux */
case 30 ... 34 : Hertz = 32; break; /* ia64 emulator */
case 48 ... 52 : Hertz = 50; break;
case 58 ... 61 : Hertz = 60; break;
case 62 ... 65 : Hertz = 64; break; /* StrongARM /Shark */
case 95 ... 105 : Hertz = 100; break; /* normal Linux */
case 124 ... 132 : Hertz = 128; break; /* MIPS, ARM */
case 195 ... 204 : Hertz = 200; break; /* normal << 1 */
case 253 ... 260 : Hertz = 256; break;
case 393 ... 408 : Hertz = 400; break; /* normal << 2 */
case 790 ... 808 : Hertz = 800; break; /* normal << 3 */
case 990 ... 1010 : Hertz = 1000; break; /* ARM */
case 1015 ... 1035 : Hertz = 1024; break; /* Alpha, ia64 */
case 1180 ... 1220 : Hertz = 1200; break; /* Alpha */
default:
#ifdef HZ
Hertz = (unsigned long long)HZ; /* <asm/param.h> */
#else
/* If 32-bit or big-endian (not Alpha or ia64), assume HZ is 100. */
Hertz = (sizeof(long)==sizeof(int) || htons(999)==999) ? 100UL : 1024UL;
#endif
fprintf(stderr, "Unknown HZ value! (%d) Assume %Ld.\n", h, Hertz);
}
}
/***********************************************************************
* The /proc filesystem calculates idle=jiffies-(user+nice+sys) and we
* recover jiffies by adding up the 4 numbers we are given. SMP kernels
* (as of pre-2.4 era) can report idle time going backwards, perhaps due
* to non-atomic reads and updates. There is no locking for these values.
*/
#ifndef NAN
#define NAN (-0.0)
#endif
#define JT unsigned long long
void four_cpu_numbers(double *uret, double *nret, double *sret, double *iret){
double tmp_u, tmp_n, tmp_s, tmp_i;
double scale; /* scale values to % */
static JT old_u, old_n, old_s, old_i;
JT new_u, new_n, new_s, new_i;
JT ticks_past; /* avoid div-by-0 by not calling too often :-( */
FILE_TO_BUF(STAT_FILE,stat_fd);
sscanf(buf, "cpu %Lu %Lu %Lu %Lu", &new_u, &new_n, &new_s, &new_i);
ticks_past = (new_u+new_n+new_s+new_i)-(old_u+old_n+old_s+old_i);
if(ticks_past){
scale = 100.0 / (double)ticks_past;
tmp_u = ( (double)new_u - (double)old_u ) * scale;
tmp_n = ( (double)new_n - (double)old_n ) * scale;
tmp_s = ( (double)new_s - (double)old_s ) * scale;
tmp_i = ( (double)new_i - (double)old_i ) * scale;
}else{
tmp_u = NAN;
tmp_n = NAN;
tmp_s = NAN;
tmp_i = NAN;
}
SET_IF_DESIRED(uret, tmp_u);
SET_IF_DESIRED(nret, tmp_n);
SET_IF_DESIRED(sret, tmp_s);
SET_IF_DESIRED(iret, tmp_i);
old_u=new_u;
old_n=new_n;
old_s=new_s;
old_i=new_i;
}
#undef JT
/***********************************************************************/
void loadavg(double *av1, double *av5, double *av15) {
double avg_1=0, avg_5=0, avg_15=0;
char *savelocale;
FILE_TO_BUF(LOADAVG_FILE,loadavg_fd);
savelocale = setlocale(LC_NUMERIC, NULL);
setlocale(LC_NUMERIC, "C");
if (sscanf(buf, "%lf %lf %lf", &avg_1, &avg_5, &avg_15) < 3) {
fprintf(stderr, "bad data in " LOADAVG_FILE "\n");
exit(1);
}
setlocale(LC_NUMERIC, savelocale);
SET_IF_DESIRED(av1, avg_1);
SET_IF_DESIRED(av5, avg_5);
SET_IF_DESIRED(av15, avg_15);
}
/***********************************************************************/
/*
* Copyright 1999 by Albert Cahalan; all rights reserved.
* This file may be used subject to the terms and conditions of the
* GNU Library General Public License Version 2, or any later version
* at your option, as published by the Free Software Foundation.
* This program 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 Library General Public License for more details.
*/
typedef struct mem_table_struct {
const char *name; /* memory type name */
const unsigned *slot; /* slot in return struct */
} mem_table_struct;
static int compare_mem_table_structs(const void *a, const void *b){
return strcmp(((mem_table_struct*)a)->name,((mem_table_struct*)b)->name);
}
/* example data, following junk, with comments added:
*
* MemTotal: 61768 kB old
* MemFree: 1436 kB old
* MemShared: 0 kB old (now always zero; not calculated)
* Buffers: 1312 kB old
* Cached: 20932 kB old
* Active: 12464 kB new
* Inact_dirty: 7772 kB new
* Inact_clean: 2008 kB new
* Inact_target: 0 kB new
* HighTotal: 0 kB
* HighFree: 0 kB
* LowTotal: 61768 kB
* LowFree: 1436 kB
* SwapTotal: 122580 kB old
* SwapFree: 60352 kB old
*/
/* obsolete */
unsigned kb_main_shared;
/* old but still kicking -- the important stuff */
unsigned kb_main_buffers;
unsigned kb_main_cached;
unsigned kb_main_free;
unsigned kb_main_total;
unsigned kb_swap_free;
unsigned kb_swap_total;
/* recently introduced */
unsigned kb_high_free;
unsigned kb_high_total;
unsigned kb_low_free;
unsigned kb_low_total;
/* 2.4.xx era */
unsigned kb_active;
unsigned kb_inact_dirty;
unsigned kb_inact_clean;
unsigned kb_inact_target;
unsigned kb_swap_cached; /* late 2.4 only */
/* derived values */
unsigned kb_swap_used;
unsigned kb_main_used;
void meminfo(void){
char namebuf[16]; /* big enough to hold any row name */
mem_table_struct findme = { namebuf, NULL};
mem_table_struct *found;
char *head;
char *tail;
static const mem_table_struct mem_table[] = {
{"Active", &kb_active},
{"Buffers", &kb_main_buffers},
{"Cached", &kb_main_cached},
{"HighFree", &kb_high_free},
{"HighTotal", &kb_high_total},
{"Inact_clean", &kb_inact_clean},
{"Inact_dirty", &kb_inact_dirty},
{"Inact_target", &kb_inact_target},
{"LowFree", &kb_low_free},
{"LowTotal", &kb_low_total},
{"MemFree", &kb_main_free},
{"MemShared", &kb_main_shared},
{"MemTotal", &kb_main_total},
{"SwapCached", &kb_swap_cached},
{"SwapFree", &kb_swap_free},
{"SwapTotal", &kb_swap_total}
};
const int mem_table_count = sizeof(mem_table)/sizeof(mem_table_struct);
FILE_TO_BUF(MEMINFO_FILE,meminfo_fd);
head = buf;
for(;;){
tail = strchr(head, ':');
if(!tail) break;
*tail = '\0';
if(strlen(head) >= sizeof(namebuf)){
head = tail+1;
goto nextline;
}
strcpy(namebuf,head);
found = bsearch(&findme, mem_table, mem_table_count,
sizeof(mem_table_struct), compare_mem_table_structs
);
head = tail+1;
if(!found) goto nextline;
*(found->slot) = strtoul(head,&tail,10);
nextline:
tail = strchr(head, '\n');
if(!tail) break;
head = tail+1;
}
if(!kb_low_total){ /* low==main except with large-memory support */
kb_low_total = kb_main_total;
kb_low_free = kb_main_free;
}
kb_swap_used = kb_swap_total - kb_swap_free;
kb_main_used = kb_main_total - kb_main_free;
}
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