helpers/log_daemon/file/log_file_daemon.cc

   1 #include "config.h"
   2
   3 #if HAVE_STDIO_H
   4 #include <stdio.h>
   5 #endif
   6 #if HAVE_STDLIB_H
   7 #include <stdlib.h>
   8 #endif
   9 #if HAVE_UNISTD_H
  10 #include <unistd.h>
  11 #endif
  12 #if HAVE_FCNTL_H
  13 #include <fcntl.h>
  14 #endif
  15 #if HAVE_ASSERT_H
  16 #include <assert.h>
  17 #endif
  18 #if HAVE_SYS_PARAM_H
  19 #include <sys/param.h>
  20 #endif
  21 #if HAVE_SYS_STAT_H
  22 #include <sys/stat.h>
  23 #endif
  24 #if HAVE_SIGNAL_H
  25 #include <signal.h>
  26 #endif
  27 #if HAVE_ERRNO_H
  28 #include <errno.h>
  29 #endif
  30 #if HAVE_STRING_H
  31 #include <string.h>
  32 #endif
  33 #if HAVE_PATHS_H
  34 #include <paths.h>
  35 #endif
  36
  37 #include "defines.h"
  38
  39 /* parse buffer - ie, length of longest expected line */
  40 #define LOGFILE_BUF_LEN         65536
  41
  42 static void
  43 rotate(const char *path, int rotate_count)
  44 {
  45 #ifdef S_ISREG
  46     struct stat sb;
  47 #endif
  48     int i;
  49     char from[MAXPATHLEN];
  50     char to[MAXPATHLEN];
  51     assert(path);
  52 #ifdef S_ISREG
  53     if (stat(path, &sb) == 0)
  54         if (S_ISREG(sb.st_mode) == 0)
  55             return;
  56 #endif
  57     /* Rotate numbers 0 through N up one */
  58     for (i = rotate_count; i > 1;) {
  59         i--;
  60         snprintf(from, MAXPATHLEN, "%s.%d", path, i - 1);
  61         snprintf(to, MAXPATHLEN, "%s.%d", path, i);
  62 #if defined(_SQUID_OS2_) || defined(_SQUID_WIN32_)
  63         remove(to);
  64 #endif
  65         rename(from, to);
  66     }
  67     if (rotate_count > 0) {
  68         snprintf(to, MAXPATHLEN, "%s.%d", path, 0);
  69 #if defined(_SQUID_OS2_) || defined(_SQUID_WIN32_)
  70         remove(to);
  71 #endif
  72         rename(path, to);
  73     }
  74 }
  75
  76 /**
  77  * The commands:
  78  *
  79  * L<data>\n - logfile data
  80  * R\n - rotate file
  81  * T\n - truncate file
  82  * O\n - repoen file
  83  * F\n - flush file
  84  * r<n>\n - set rotate count to <n>
  85  * b<n>\n - 1 = buffer output, 0 = don't buffer output
  86  */
  87 int
  88 main(int argc, char *argv[])
  89 {
  90     int t;
  91     FILE *fp;
  92     char buf[LOGFILE_BUF_LEN];
  93     int rotate_count = 10;
  94     int do_buffer = 1;
  95
  96     if (argc < 2) {
  97         printf("Error: usage: %s <logfile>\n", argv[0]);
  98         exit(1);
  99     }
 100     fp = fopen(argv[1], "a");
 101     if (fp == NULL) {
 102         perror("fopen");
 103         exit(1);
 104     }
 105     setbuf(stdout, NULL);
 106     close(2);
 107     t = open(_PATH_DEVNULL, O_RDWR);
 108     assert(t > -1);
 109     dup2(t, 2);
 110
 111     while (fgets(buf, LOGFILE_BUF_LEN, stdin)) {
 112         /* First byte indicates what we're logging! */
 113         switch (buf[0]) {
 114         case 'L':
 115             if (buf[1] != '\0') {
 116                 fprintf(fp, "%s", buf + 1);
 117                 /* try to detect the 32-bit file too big write error and rotate */
 118                 int err = ferror(fp);
 119                 clearerr(fp);
 120                 if (err < 0) {
 121                     /* file too big - recover by rotating the logs and starting a new one.
 122                      * out of device space - recover by rotating and hoping that rotation count drops a big one.
 123                      */
 124                     if (err == EFBIG || err == ENOSPC) {
 125                         fprintf(stderr, "WARNING: %s writing %s. Attempting to recover via a log rotation.\n",strerror(err),argv[1]);
 126                         fclose(fp);
 127                         rotate(argv[1], rotate_count);
 128                         fp = fopen(argv[1], "a");
 129                         if (fp == NULL) {
 130                             perror("fopen");
 131                             exit(1);
 132                         }
 133                         fprintf(fp, "%s", buf + 1);
 134                     } else {
 135                         perror("fprintf");
 136                         exit(1);
 137                     }
 138                 }
 139             }
 140             if (!do_buffer)
 141                 fflush(fp);
 142             break;
 143         case 'R':
 144             fclose(fp);
 145             rotate(argv[1], rotate_count);
 146             fp = fopen(argv[1], "a");
 147             if (fp == NULL) {
 148                 perror("fopen");
 149                 exit(1);
 150             }
 151             break;
 152         case 'T':
 153             break;
 154         case 'O':
 155             break;
 156         case 'r':
 157             //fprintf(fp, "SET ROTATE: %s\n", buf + 1);
 158             rotate_count = atoi(buf + 1);
 159             break;
 160         case 'b':
 161             //fprintf(fp, "SET BUFFERED: %s\n", buf + 1);
 162             do_buffer = (buf[1] == '1');
 163             break;
 164         case 'F':
 165             fflush(fp);
 166             break;
 167         default:
 168             /* Just in case .. */
 169             fprintf(fp, "%s", buf);
 170             break;
 171         }
 172     }
 173     fclose(fp);
 174     fp = NULL;
 175     exit(0);
 176 }