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

   1 /* darkstat 3
   2  * copyright (c) 2007-2014 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 "cdefs.h"
  13 #include "err.h"
  14 #include "daylog.h"
  15 #include "str.h"
  16 #include "now.h"
  17
  18 #include <assert.h>
  19 #include <fcntl.h>
  20 #include <stdarg.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <time.h>
  24 #include <unistd.h>
  25
  26 static const char *daylog_fn = NULL;
  27 static time_t today_real, tomorrow_real;
  28 static uint64_t bytes_in, bytes_out, pkts_in, pkts_out;
  29
  30 #define DAYLOG_DATE_LEN 26 /* strlen("1900-01-01 00:00:00 +1234") + 1 */
  31 static char datebuf[DAYLOG_DATE_LEN];
  32
  33 static char *fmt_date(time_t when) {
  34     if (strftime(datebuf,
  35                  DAYLOG_DATE_LEN,
  36                  "%Y-%m-%d %H:%M:%S %z",
  37                  localtime(&when)) == 0)
  38             errx(1, "strftime() failed in fmt_date()");
  39     return datebuf;
  40 }
  41
  42 /* Given some time today, find the first second of tomorrow. */
  43 static time_t tomorrow(time_t t_before) {
  44    time_t t_after;
  45    struct tm tm, *lt;
  46
  47    lt = localtime(&t_before);
  48    memcpy(&tm, lt, sizeof(tm));
  49    tm.tm_sec = 0;
  50    tm.tm_min = 0;
  51    tm.tm_hour = 0;
  52    tm.tm_mday = lt->tm_mday + 1; /* tomorrow */
  53    t_after = mktime(&tm);
  54    assert(t_after > t_before);
  55    return t_after;
  56 }
  57
  58 /* Warns on error. */
  59 static void daylog_write(const char *format, ...) _printflike_(1, 2);
  60 static void daylog_write(const char *format, ...) {
  61    int fd;
  62    ssize_t wr;
  63    va_list va;
  64    struct str *buf;
  65
  66    assert(daylog_fn != NULL);
  67    fd = open(daylog_fn, O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW, 0600);
  68    if (fd == -1) {
  69       warn("daylog_write: couldn't open '%s' for append", daylog_fn);
  70       return;
  71    }
  72
  73    buf = str_make();
  74    va_start(va, format);
  75    str_vappendf(buf, format, va);
  76    va_end(va);
  77
  78    wr = str_write(buf, fd);
  79    if (wr == -1)
  80       warn("daylog_write: couldn't write to '%s'", daylog_fn);
  81    else if (wr != (ssize_t)str_len(buf))
  82       warnx("daylog_write: truncated write to '%s': wrote %d of %d bytes",
  83            daylog_fn,
  84            (int)wr,
  85            (int)str_len(buf));
  86    close(fd);
  87    str_free(buf);
  88 }
  89
  90 static void daylog_emit(void) {
  91    daylog_write("%s|%qu|%qu|%qu|%qu|%qu\n",
  92                 fmt_date(today_real),
  93                 (qu)today_real,
  94                 (qu)bytes_in,
  95                 (qu)bytes_out,
  96                 (qu)pkts_in,
  97                 (qu)pkts_out);
  98 }
  99
 100 void daylog_init(const char *filename) {
 101    daylog_fn = filename;
 102    today_real = now_real();
 103    tomorrow_real = tomorrow(today_real);
 104    verbosef("today is %llu, tomorrow is %llu",
 105             (llu)today_real,
 106             (llu)tomorrow_real);
 107    bytes_in = bytes_out = pkts_in = pkts_out = 0;
 108
 109    daylog_write("# logging started at %s (%qu)\n",
 110                 fmt_date(today_real), (qu)today_real);
 111 }
 112
 113 void daylog_free(void) {
 114    today_real = now_real();
 115    daylog_emit(); /* Emit what's currently accumulated before we exit. */
 116    daylog_write("# logging stopped at %s (%qu)\n",
 117                 fmt_date(today_real), (qu)today_real);
 118 }
 119
 120 void daylog_acct(uint64_t amount, enum graph_dir dir) {
 121    if (daylog_fn == NULL)
 122       return; /* daylogging disabled */
 123
 124    /* Check if we need to update the log. */
 125    if (now_real() >= tomorrow_real) {
 126       daylog_emit();
 127
 128       today_real = now_real();
 129       tomorrow_real = tomorrow(today_real);
 130       bytes_in = bytes_out = pkts_in = pkts_out = 0;
 131       verbosef("updated daylog, tomorrow = %llu", (llu)tomorrow_real);
 132    }
 133
 134    /* Accounting. */
 135    if (dir == GRAPH_IN) {
 136       bytes_in += amount;
 137       pkts_in++;
 138    } else {
 139       assert(dir == GRAPH_OUT);
 140       bytes_out += amount;
 141       pkts_out++;
 142    }
 143 }
 144
 145 /* vim:set ts=3 sw=3 tw=78 et: */