procps/proc/vmstat.c
Craig Small ca4a09c432 library: memory and vmstat API changes
Created new set of functions for meminfo related calls. Liked the
format of that better so changed vmstat around so the look similar.
Missed the makefile change for uptime so added it in now.
2015-06-26 22:37:28 +10:00

156 lines
3.1 KiB
C

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <proc/vmstat.h>
#include "procps-private.h"
#define VMSTAT_FILE "/proc/vmstat"
#define ROW_NAME_LEN 32
struct vmstat_data {
unsigned long pgpgin;
unsigned long pgpgout;
unsigned long pswpin;
unsigned long pswpout;
};
struct mem_table_struct {
const char *name;
unsigned long *slot;
};
struct procps_vmstat {
int refcount;
int vmstat_fd;
struct vmstat_data data;
};
/*
* procps_vmstat_new:
*
* Create a new container to hold the vmstat information
*
* The initial refcount is 1, and needs to be decremented
* to release the resources of the structure.
*
* Returns: a new procps_vmstat container
*/
PROCPS_EXPORT int procps_vmstat_new(struct procps_vmstat **info)
{
struct procps_vmstat *v;
v = calloc(1, sizeof(struct procps_vmstat));
if (!v)
return -ENOMEM;
v->refcount = 1;
v->vmstat_fd = -1;
*info = v;
return 0;
}
/*
* procps_vmstat_read:
*
* Read the data out of /proc/vmstat putting the information
* into the supplied info structure
*
* Returns: 0 on success, negative on error
*/
PROCPS_EXPORT int procps_vmstat_read(struct procps_vmstat *info)
{
char buf[8192];
char *head, *tail;
int size;
unsigned long *valptr;
if (info == NULL)
return -1;
memset(&(info->data), 0, sizeof(struct vmstat_data));
/* read in the data */
if (-1 == info->vmstat_fd && (info->vmstat_fd = open(VMSTAT_FILE, O_RDONLY)) == -1) {
return -errno;
}
if (lseek(info->vmstat_fd, 0L, SEEK_SET) == -1) {
return -errno;
}
if ((size = read(info->vmstat_fd, buf, sizeof(buf)-1)) < 0) {
return -1;
}
buf[size] = '\0';
/* Scan the file */
head = buf;
do {
tail = strchr(head, ' ');
if (!tail)
break;
*tail = '\0';
valptr = NULL;
if (0 == strcmp(head, "pgpgin")) {
valptr = &(info->data.pgpgin);
}else if (0 == strcmp(head, "pgpgout")) {
valptr = &(info->data.pgpgout);
}else if (0 == strcmp(head, "pswpin")) {
valptr = &(info->data.pswpin);
}else if (0 == strcmp(head, "pswpout")) {
valptr = &(info->data.pswpout);
}
head = tail+1;
if (valptr) {
*valptr = strtoul(head, &tail, 10);
}
tail = strchr(head, '\n');
if (!tail)
break;
head = tail + 1;
} while(tail);
return 0;
}
PROCPS_EXPORT struct procps_vmstat *procps_vmstat_ref(struct procps_vmstat *info)
{
if (info == NULL)
return NULL;
info->refcount++;
return info;
}
PROCPS_EXPORT struct procps_vmstat *procps_vmstat_unref(struct procps_vmstat *info)
{
if (info == NULL)
return NULL;
info->refcount--;
if (info->refcount > 0)
return NULL;
free(info);
return NULL;
}
/* Accessor functions */
PROCPS_EXPORT unsigned long procps_vmstat_get(
struct procps_vmstat *info,
enum vmstat_item item)
{
switch(item) {
case PROCPS_VMSTAT_PGPGIN:
return info->data.pgpgin;
case PROCPS_VMSTAT_PGPGOUT:
return info->data.pgpgout;
case PROCPS_VMSTAT_PSWPIN:
return info->data.pswpin;
case PROCPS_VMSTAT_PSWPOUT:
return info->data.pswpout;
}
return 0;
}