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#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include "cpu-top.h"
int cpu_top_update(struct cpu_top *cpu)
{
struct cpu_stat *s = &cpu->stat[cpu->count++&1];
struct cpu_stat *d = &cpu->stat[cpu->count&1];
uint64_t d_total, d_idle;
char buf[4096];
int fd, len = -1;
fd = open("/proc/stat", 0);
if (fd < 0)
return errno;
len = read(fd, buf, sizeof(buf)-1);
close(fd);
if (len < 0)
return EIO;
buf[len] = '\0';
#ifdef __x86_64__
sscanf(buf, "cpu %lu %lu %lu %lu",
&s->user, &s->nice, &s->sys, &s->idle);
#else
sscanf(buf, "cpu %llu %llu %llu %llu",
&s->user, &s->nice, &s->sys, &s->idle);
#endif
s->total = s->user + s->nice + s->sys + s->idle;
if (cpu->count == 1)
return EAGAIN;
d_total = s->total - d->total;
d_idle = s->idle - d->idle;
cpu->busy = 100 - 100 * d_idle / d_total;
return 0;
}
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