iostat.c

   1 /*
   2  * Copyright (C) 2012-2020 all contributors <cmogstored-public@yhbt.net>
   3  * License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
   4  */
   5
   6 /*
   7  * iostat(1) -> global mountlist -> each mog_dev in each mog_svc
   8  */
   9 #include "cmogstored.h"
  10
  11 /* called after a stats line for a single device is complete */
  12 void mog_iostat_line_done(struct mog_iostat *iostat)
  13 {
  14         if (iostat->dev_tip < sizeof(iostat->dev)) {
  15                 iostat->dev[iostat->dev_tip] = 0;
  16                 if (iostat->util_tip < sizeof(iostat->util)) {
  17                         iostat->util[iostat->util_tip] = 0;
  18                 } else {
  19                         iostat->util[0] = '-';
  20                         iostat->util[1] = 0;
  21                 }
  22
  23                 mog_mnt_update_util(iostat);
  24         } else {
  25                 syslog(LOG_ERR, "device name from iostat too long");
  26         }
  27 }
  28
  29 /* called every second, after stats for each device line are out */
  30 void mog_iostat_commit(void)
  31 {
  32         mog_svc_each(mog_svc_devstats_broadcast, NULL);
  33 }
  34
  35 static void iostat_close(struct mog_fd *mfd)
  36 {
  37         assert(mfd->fd_type == MOG_FD_TYPE_IOSTAT && "bad fd_type");
  38         mog_fd_put(mfd);
  39 }
  40
  41 static void iostat_reset(struct mog_iostat *iostat)
  42 {
  43         bool ready = iostat->ready;
  44         mog_iostat_init(iostat);
  45         iostat->ready = ready;
  46 }
  47
  48 void mog_iostat_queue_step(struct mog_fd *mfd)
  49 {
  50         /*
  51          * only one thread ever hits this function at once,
  52          * no point in ever running multiple iostat(1) processes
  53          */
  54         static char buf[1024];
  55         ssize_t r;
  56         struct mog_iostat *iostat = &mfd->as.iostat;
  57
  58         assert(mfd->fd >= 0 && mfd->fd_type == MOG_FD_TYPE_IOSTAT &&
  59                "bad iostat mfd");
  60 retry:
  61         r = read(mfd->fd, buf, sizeof(buf));
  62         if (r > 0) {
  63                 switch (mog_iostat_parse(iostat, buf, r)) {
  64                 case MOG_PARSER_ERROR:
  65                         syslog(LOG_ERR, "iostat parser error");
  66                         iostat_close(mfd);
  67                         return;
  68                 case MOG_PARSER_DONE:
  69                         iostat_reset(iostat);
  70                         goto retry;
  71                 case MOG_PARSER_CONTINUE:
  72                         goto retry;
  73                 }
  74         } else if (r == 0) {
  75                 /* iostat exits every 30s by default */
  76                 iostat_close(mfd);
  77         } else {
  78                 switch (errno) {
  79                 case_EAGAIN:
  80                         mog_idleq_push(iostat->queue, mfd, MOG_QEV_RD);
  81                         return;
  82                 case EINTR: goto retry;
  83                 }
  84                 syslog(LOG_ERR, "iostat read() failed: %m");
  85                 iostat_close(mfd);
  86         }
  87 }