LXR linux/fs/proc/uptime.c

   1#include <linux/init.h>
   2#include <linux/proc_fs.h>
   3#include <linux/sched.h>
   4#include <linux/time.h>
   5#include <asm/cputime.h>
   6
   7static int proc_calc_metrics(char *page, char **start, off_t off,
   8                                 int count, int *eof, int len)
   9{
  10        if (len <= off + count)
  11                *eof = 1;
  12        *start = page + off;
  13        len -= off;
  14        if (len > count)
  15                len = count;
  16        if (len < 0)
  17                len = 0;
  18        return len;
  19}
  20
  21static int uptime_read_proc(char *page, char **start, off_t off, int count,
  22                            int *eof, void *data)
  23{
  24        struct timespec uptime;
  25        struct timespec idle;
  26        int len;
  27        cputime_t idletime = cputime_add(init_task.utime, init_task.stime);
  28
  29        do_posix_clock_monotonic_gettime(&uptime);
  30        monotonic_to_bootbased(&uptime);
  31        cputime_to_timespec(idletime, &idle);
  32        len = sprintf(page, "%lu.%02lu %lu.%02lu\n",
  33                        (unsigned long) uptime.tv_sec,
  34                        (uptime.tv_nsec / (NSEC_PER_SEC / 100)),
  35                        (unsigned long) idle.tv_sec,
  36                        (idle.tv_nsec / (NSEC_PER_SEC / 100)));
  37        return proc_calc_metrics(page, start, off, count, eof, len);
  38}
  39
  40static int __init proc_uptime_init(void)
  41{
  42        create_proc_read_entry("uptime", 0, NULL, uptime_read_proc, NULL);
  43        return 0;
  44}
  45module_init(proc_uptime_init);
  46