wmsupermon/stat_dev.c

   1 /* Copyright (C) 2006 Sergei Golubchik
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License version 2
   5    as published by the Free Software Foundation
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
  15
  16 /*
  17   originally based on
  18     WMgMon - Window Maker Generic Monitor
  19     by Nicolas Chauvat <nico@caesium.fr>
  20 */
  21
  22 #include <stdlib.h>
  23 #include <regex.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <errno.h>
  27 #include <unistd.h>
  28 #include <math.h>
  29 #include "expr.h"
  30 #include "stat_dev.h"
  31
  32 /******************************************************************************/
  33 /* stat_dev structure and related functions                                   */
  34 /******************************************************************************/
  35
  36 void stat_dev_init(stat_dev * st)
  37 {
  38    bzero(st, sizeof(*st));
  39    st->update_interval=1;
  40    st->hist_update_interval=5;
  41 }
  42
  43 void stat_dev_initstat (stat_dev * st)
  44 {
  45   if (st->flags & F_USED)
  46     update_stat(st); /* to get first value for DIFF */
  47   else
  48     st->next_update=~0; /* that is never */
  49 }
  50
  51 void stat_dev_update_history (stat_dev *st)
  52 {
  53   int i;
  54   for (i=0; i <= P_HIST; i++) {
  55     int j;
  56     history *hist=st->hist[i];
  57     if (!hist) continue;
  58
  59     /* history is updated more often than the value is sampled. Use previous
  60        value to avoid a gap in the history */
  61     if (hist->count == 0)
  62       hist->data[HIST_LAST]=hist->data[HIST_LAST-1];
  63
  64     /* we probably sampled several times since last time we updated,
  65        let's normalize value by dividing by the number of times we sampled */
  66     if (hist->count > 1)
  67        hist->data[HIST_LAST] /= hist->count;
  68
  69     if (i & P_LOG && hist->count)
  70       hist->data[HIST_LAST]=hist->data[HIST_LAST]*3 <= 1 ?
  71         0 : log(hist->data[HIST_LAST]*3);
  72
  73     /* shift values to the left (discard his[0]) */
  74     for (j=1; j < HIST_SIZE; j++)
  75        hist->data[j-1]=hist->data[j];
  76
  77      /* reset sample */
  78      hist->data[HIST_LAST]=0;
  79      hist->count=0;
  80   }
  81 }
  82
  83 /******************************************************************************/
  84 /* update stat functions                                                      */
  85 /******************************************************************************/
  86
  87 /* returns 1 on a match */
  88 static int do_regex(stat_dev *st, char *str) {
  89   regmatch_t pmatch[MAX_VAR];
  90   Econtext ctx={str, pmatch, st->diff_old, st->diff_new, st->sum_acc};
  91
  92   if (regexec(&st->regex, str, MAX_VAR, pmatch, 0))
  93     return 0;
  94
  95   st->value[0]=st->expr->eval(st->expr, &ctx)/st->scale;
  96   return 1;
  97 }
  98
  99 static void stat_perror(stat_dev *st, char *op)
 100 {
 101   fprintf(stderr, "[%s]: %s() failed: %s\n", st->name, op, strerror(errno));
 102 }
 103
 104 void update_stat(stat_dev *st)
 105 {
 106   char *buf;
 107   double *tmp;
 108   FILE *f;
 109   int matched=0;
 110
 111   f= (st->source[0] == '!') ?
 112       popen(st->source+1, "r") : fopen(st->source, "r");
 113
 114   if (!f) {
 115     stat_perror(st, "open");
 116     return;
 117   }
 118
 119   if (!st->expr) {
 120     double value;
 121     if (fscanf(f, "%lf", &value) == 1)
 122       st->value[0]=value/st->scale;
 123     goto done;
 124   }
 125
 126   /* ok, doing regexp */
 127   if (st->flags & F_SINGLE_LINE) {
 128     struct stat stat;
 129     if (fstat(fileno(f), &stat) < 0) { stat_perror(st, "fstat"); goto ret; }
 130     if (stat.st_size < MIN_FILE_LEN)
 131       stat.st_size=MIN_FILE_LEN; /* because /proc files may have zero length */
 132     buf=malloc(stat.st_size); /* and it'd better be small! */
 133     if (!buf) { stat_perror(st, "malloc"); goto ret; }
 134     fread(buf, stat.st_size,  1, f);
 135     matched=do_regex(st, buf);
 136     free(buf);
 137     goto done;
 138   }
 139
 140   buf=alloca(TEMP_SIZE);
 141   if (st->nsum) bzero(st->sum_acc, st->nsum*sizeof(double));
 142   while (fgets(buf, TEMP_SIZE, f)) {
 143     if ((matched|=do_regex(st, buf)) && !st->nsum)
 144       break;
 145   }
 146
 147 done:
 148   if (st->flags & F_DEBUG) {
 149     if (matched)
 150       printf("%-4s: %f\n", st->name, st->value[0]);
 151     else
 152       printf("%-4s: match failed\n", st->name);
 153   }
 154
 155   tmp=st->diff_old; st->diff_old=st->diff_new; st->diff_new=tmp;
 156
 157 ret:
 158   (st->source[0] == '!') ?  pclose(f) : fclose(f);
 159 }
 160