unix4lyfe git - darkstat-debian/blob - daylog.c

   1 /* darkstat 3
   2  * copyright (c) 2007-2011 Emil Mikulic.
   3  *
   4  * daylog.c: daily usage log
   5  *
   6  * You may use, modify and redistribute this file under the terms of the
   7  * GNU General Public License version 2. (see COPYING.GPL)
   8  */
   9
  10 #define _GNU_SOURCE 1 /* for O_NOFOLLOW on Linux */
  11
  12 #include "err.h"
  13 #include "daylog.h"
  14 #include "str.h"
  15 #include "now.h"
  16
  17 #include <assert.h>
  18 #include <fcntl.h>
  19 #include <stdarg.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <time.h>
  23 #include <unistd.h>
  24
  25 static const char *daylog_fn = NULL;
  26 static long today_real, tomorrow_real;
  27 static uint64_t bytes_in, bytes_out, pkts_in, pkts_out;
  28
  29 #define DAYLOG_DATE_LEN 26 /* strlen("1900-01-01 00:00:00 +1234") + 1 */
  30 static char datebuf[DAYLOG_DATE_LEN];
  31
  32 static char *fmt_date(time_t when) {
  33     if (strftime(datebuf,
  34                  DAYLOG_DATE_LEN,
  35                  "%Y-%m-%d %H:%M:%S %z",
  36                  localtime(&when)) == 0)
  37             errx(1, "strftime() failed in fmt_date()");
  38     return datebuf;
  39 }
  40
  41 /* Given some time today, find the first second of tomorrow. */
  42 static time_t tomorrow(time_t t_before) {
  43    time_t t_after;
  44    struct tm tm, *lt;
  45
  46    lt = localtime(&t_before);
  47    memcpy(&tm, lt, sizeof(tm));
  48    tm.tm_sec = 0;
  49    tm.tm_min = 0;
  50    tm.tm_hour = 0;
  51    tm.tm_mday = lt->tm_mday + 1; /* tomorrow */
  52    t_after = mktime(&tm);
  53    assert(t_after > t_before);
  54    return t_after;
  55 }
  56
  57 /* Warns on error. */
  58 static void daylog_write(const char *format, ...) {
  59    int fd;
  60    ssize_t wr;
  61    va_list va;
  62    struct str *buf;
  63
  64    assert(daylog_fn != NULL);
  65    fd = open(daylog_fn, O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW, 0600);
  66    if (fd == -1) {
  67       warn("daylog_write: couldn't open '%s' for append", daylog_fn);
  68       return;
  69    }
  70
  71    buf = str_make();
  72    va_start(va, format);
  73    str_vappendf(buf, format, va);
  74    va_end(va);
  75
  76    wr = str_write(buf, fd);
  77    if (wr == -1)
  78       warn("daylog_write: couldn't write to '%s'", daylog_fn);
  79    else if (wr != (ssize_t)str_len(buf))
  80       warnx("daylog_write: truncated write to '%s': wrote %d of %d bytes",
  81            daylog_fn,
  82            (int)wr,
  83            (int)str_len(buf));
  84    close(fd);
  85    str_free(buf);
  86 }
  87
  88 static void daylog_emit(void) {
  89    daylog_write("%s|%qu|%qu|%qu|%qu|%qu\n",
  90                 fmt_date(today_real), (uint64_t)today_real,
  91                 bytes_in, bytes_out, pkts_in, pkts_out);
  92 }
  93
  94 void daylog_init(const char *filename) {
  95    daylog_fn = filename;
  96    today_real = now_real();
  97    tomorrow_real = tomorrow(today_real);
  98    verbosef("today is %ld, tomorrow is %ld",
  99             (long)today_real, (long)tomorrow_real);
 100    bytes_in = bytes_out = pkts_in = pkts_out = 0;
 101
 102    daylog_write("# logging started at %s (%qu)\n",
 103                 fmt_date(today_real), (uint64_t)today_real);
 104 }
 105
 106 void daylog_free(void) {
 107    today_real = now_real();
 108    daylog_emit(); /* Emit what's currently accumulated before we exit. */
 109    daylog_write("# logging stopped at %s (%qu)\n",
 110                 fmt_date(today_real), (uint64_t)today_real);
 111 }
 112
 113 void daylog_acct(uint64_t amount, enum graph_dir dir) {
 114    if (daylog_fn == NULL)
 115       return; /* daylogging disabled */
 116
 117    /* Check if we need to update the log. */
 118    if (now_real() >= tomorrow_real) {
 119       daylog_emit();
 120
 121       today_real = now_real();
 122       tomorrow_real = tomorrow(today_real);
 123       bytes_in = bytes_out = pkts_in = pkts_out = 0;
 124       verbosef("updated daylog, tomorrow = %ld", (long)tomorrow_real);
 125    }
 126
 127    /* Accounting. */
 128    if (dir == GRAPH_IN) {
 129       bytes_in += amount;
 130       pkts_in++;
 131    } else {
 132       assert(dir == GRAPH_OUT);
 133       bytes_out += amount;
 134       pkts_out++;
 135    }
 136 }
 137
 138 /* vim:set ts=3 sw=3 tw=78 et: */