log/syslog.c

   1 /*
   2  * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/un.h>
  15
  16 #include <sys/types.h>
  17 #include <sys/socket.h>
  18 #include <sys/stat.h>
  19
  20 #include <fcntl.h>
  21 #include <regex.h>
  22 #include <time.h>
  23 #include <unistd.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27 #include <syslog.h>
  28 #include <errno.h>
  29
  30 #include <libubox/uloop.h>
  31 #include <libubox/usock.h>
  32 #include <libubox/ustream.h>
  33
  34 #include "syslog.h"
  35
  36 #define LOG_DEFAULT_SIZE        (16 * 1024)
  37 #define LOG_DEFAULT_SOCKET      "/dev/log"
  38 #define SYSLOG_PADDING          16
  39
  40 #define MAXLINE                 1024
  41
  42 #define KLOG_DEFAULT_PROC       "/proc/kmsg"
  43
  44 #define PAD(x) (x % 4) ? (((x) - (x % 4)) + 4) : (x)
  45
  46 static char *log_dev = LOG_DEFAULT_SOCKET;
  47 static int log_size = LOG_DEFAULT_SIZE;
  48 static struct log_head *log, *log_end, *oldest, *newest;
  49 static int current_id = 0;
  50 static regex_t pat_prio;
  51 static regex_t pat_tstamp;
  52
  53 static struct log_head*
  54 log_next(struct log_head *h, int size)
  55 {
  56         struct log_head *n = (struct log_head *) &h->data[PAD(size)];
  57
  58         return (n >= log_end) ? (log) : (n);
  59 }
  60
  61 void
  62 log_add(char *buf, int size, int source)
  63 {
  64         regmatch_t matches[4];
  65         struct log_head *next;
  66         int priority = 0;
  67         int ret;
  68
  69         /* bounce out if we don't have init'ed yet (regmatch etc will blow) */
  70         if (!log) {
  71                 fprintf(stderr, "%s", buf);
  72                 return;
  73         }
  74
  75         /* strip trailing newline */
  76         if (buf[size - 2] == '\n') {
  77                 buf[size - 2] = '\0';
  78                 size -= 1;
  79         }
  80
  81         /* strip the priority */
  82         ret = regexec(&pat_prio, buf, 3, matches, 0);
  83         if (!ret) {
  84                 priority = atoi(&buf[matches[1].rm_so]);
  85                 size -= matches[2].rm_so;
  86                 buf += matches[2].rm_so;
  87         }
  88
  89 #if 0
  90         /* strip kernel timestamp */
  91         ret = regexec(&pat_tstamp,buf, 4, matches, 0);
  92         if ((source == SOURCE_KLOG) && !ret) {
  93                 size -= matches[3].rm_so;
  94                 buf += matches[3].rm_so;
  95         }
  96 #endif
  97
  98         /* strip syslog timestamp */
  99         if ((source == SOURCE_SYSLOG) && (size > SYSLOG_PADDING) && (buf[SYSLOG_PADDING - 1] == ' ')) {
 100                 size -= SYSLOG_PADDING;
 101                 buf += SYSLOG_PADDING;
 102         }
 103
 104         //fprintf(stderr, "-> %d - %s\n", priority, buf);
 105
 106         /* find new oldest entry */
 107         next = log_next(newest, size);
 108         if (next > newest) {
 109                 while ((oldest > newest) && (oldest <= next) && (oldest != log))
 110                         oldest = log_next(oldest, oldest->size);
 111         } else {
 112                 //fprintf(stderr, "Log wrap\n");
 113                 newest->size = 0;
 114                 next = log_next(log, size);
 115                 for (oldest = log; oldest <= next; oldest = log_next(oldest, oldest->size))
 116                         ;
 117                 newest = log;
 118         }
 119
 120         /* add the log message */
 121         newest->size = size;
 122         newest->id = current_id++;
 123         newest->priority = priority;
 124         newest->source = source;
 125         clock_gettime(CLOCK_REALTIME, &newest->ts);
 126         strcpy(newest->data, buf);
 127
 128         ubus_notify_log(newest);
 129
 130         newest = next;
 131 }
 132
 133 static void
 134 syslog_handle_fd(struct uloop_fd *fd, unsigned int events)
 135 {
 136         static char buf[MAXLINE];
 137         int len;
 138
 139         while (1) {
 140                 char *c;
 141
 142                 len = recv(fd->fd, buf, MAXLINE - 1, 0);
 143                 if (len < 0) {
 144                         if (errno == EINTR)
 145                                 continue;
 146
 147                         break;
 148                 }
 149                 if (!len)
 150                         break;
 151
 152                 buf[len] = 0;
 153                 for (c = buf; *c; c++) {
 154                     if (*c == '\n')
 155                         *c = ' ';
 156                 }
 157
 158                 log_add(buf, c - buf + 1, SOURCE_SYSLOG);
 159         }
 160 }
 161
 162 static void
 163 klog_cb(struct ustream *s, int bytes)
 164 {
 165         struct ustream_buf *buf = s->r.head;
 166         char *newline, *str;
 167         int len;
 168
 169         do {
 170                 str = ustream_get_read_buf(s, NULL);
 171                 if (!str)
 172                         break;
 173                 newline = strchr(buf->data, '\n');
 174                 if (!newline)
 175                         break;
 176                 *newline = 0;
 177                 len = newline + 1 - str;
 178                 log_add(buf->data, len, SOURCE_KLOG);
 179                 ustream_consume(s, len);
 180         } while (1);
 181 }
 182
 183 static struct uloop_fd syslog_fd = {
 184         .cb = syslog_handle_fd
 185 };
 186
 187 static struct ustream_fd klog = {
 188         .stream.string_data = true,
 189         .stream.notify_read = klog_cb,
 190 };
 191
 192 static int
 193 klog_open(void)
 194 {
 195         int fd;
 196
 197         fd = open(KLOG_DEFAULT_PROC, O_RDONLY | O_NONBLOCK);
 198         if (fd < 0) {
 199                 fprintf(stderr, "Failed to open %s\n", KLOG_DEFAULT_PROC);
 200                 return -1;
 201         }
 202         fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
 203         ustream_fd_init(&klog, fd);
 204         return 0;
 205 }
 206
 207 static int
 208 syslog_open(void)
 209 {
 210         unlink(log_dev);
 211         syslog_fd.fd = usock(USOCK_UNIX | USOCK_UDP | USOCK_SERVER | USOCK_NONBLOCK, log_dev, NULL);
 212         if (syslog_fd.fd < 0) {
 213                 fprintf(stderr,"Failed to open %s\n", log_dev);
 214                 return -1;
 215         }
 216         chmod(log_dev, 0666);
 217         uloop_fd_add(&syslog_fd, ULOOP_READ | ULOOP_EDGE_TRIGGER);
 218
 219         return 0;
 220 }
 221
 222 struct log_head*
 223 log_list(int count, struct log_head *h)
 224 {
 225         unsigned int min = count;
 226
 227         if (count)
 228                 min = (count < current_id) ? (current_id - count) : (0);
 229         if (!h && oldest->id >= min)
 230                 return oldest;
 231         if (!h)
 232                 h = oldest;
 233
 234         while (h != newest) {
 235                 h = log_next(h, h->size);
 236                 if (!h->size && (h > newest))
 237                         h = log;
 238                 if (h->id >= min && (h != newest))
 239                         return h;
 240         }
 241
 242         return NULL;
 243 }
 244
 245 int
 246 log_buffer_init(int size)
 247 {
 248         struct log_head *_log = malloc(size);
 249
 250         if (!_log) {
 251                 fprintf(stderr, "Failed to initialize log buffer with size %d\n", log_size);
 252                 return -1;
 253         }
 254
 255         memset(_log, 0, size);
 256
 257         if (log && ((log_size + sizeof(struct log_head)) < size)) {
 258                 struct log_head *start = _log;
 259                 struct log_head *end = ((void*) _log) + size;
 260                 struct log_head *l;
 261
 262                 l = log_list(0, NULL);
 263                 while ((start < end) && l && l->size) {
 264                         memcpy(start, l, PAD(sizeof(struct log_head) + l->size));
 265                         start = (struct log_head *) &l->data[PAD(l->size)];
 266                         l = log_list(0, l);
 267                 }
 268                 free(log);
 269                 newest = start;
 270                 newest->size = 0;
 271                 oldest = log = _log;
 272                 log_end = ((void*) log) + size;
 273         } else {
 274                 oldest = newest = log = _log;
 275                 log_end = ((void*) log) + size;
 276         }
 277         log_size = size;
 278
 279         return 0;
 280 }
 281
 282 void
 283 log_init(int _log_size)
 284 {
 285         if (_log_size > 0)
 286                 log_size = _log_size;
 287
 288         regcomp(&pat_prio, "^<([0-9]*)>(.*)", REG_EXTENDED);
 289         regcomp(&pat_tstamp, "^\[[ 0]*([0-9]*).([0-9]*)] (.*)", REG_EXTENDED);
 290
 291         if (log_buffer_init(log_size)) {
 292                 fprintf(stderr, "Failed to allocate log memory\n");
 293                 exit(-1);
 294         }
 295
 296         syslog_open();
 297         klog_open();
 298         openlog("sysinit", LOG_CONS, LOG_DAEMON);
 299 }
 300
 301 void
 302 log_shutdown(void)
 303 {
 304         if (syslog_fd.registered) {
 305                 uloop_fd_delete(&syslog_fd);
 306                 close(syslog_fd.fd);
 307         }
 308
 309         ustream_free(&klog.stream);
 310         close(klog.fd.fd);
 311         free(log);
 312         regfree(&pat_prio);
 313         regfree(&pat_tstamp);
 314 }