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
  29 #include <libubox/uloop.h>
  30 #include <libubox/usock.h>
  31 #include <libubox/ustream.h>
  32
  33 #include "syslog.h"
  34
  35 #define LOG_DEFAULT_SIZE        (16 * 1024)
  36 #define LOG_DEFAULT_SOCKET      "/dev/log"
  37 #define LOG_LINE_LEN            256
  38 #define SYSLOG_PADDING          16
  39
  40 #define KLOG_DEFAULT_PROC       "/proc/kmsg"
  41
  42 #define PAD(x) (x % 4) ? (((x) - (x % 4)) + 4) : (x)
  43
  44 static char *log_dev = LOG_DEFAULT_SOCKET;
  45 static int log_size = LOG_DEFAULT_SIZE;
  46 static struct log_head *log, *log_end, *oldest, *newest;
  47 static int current_id = 0;
  48 static regex_t pat_prio;
  49 static regex_t pat_tstamp;
  50
  51 static struct log_head*
  52 log_next(struct log_head *h, int size)
  53 {
  54         struct log_head *n = (struct log_head *) &h->data[PAD(sizeof(struct log_head) + size)];
  55
  56         return (n >= log_end) ? (log) : (n);
  57 }
  58
  59 void
  60 log_add(char *buf, int size, int source)
  61 {
  62         regmatch_t matches[4];
  63         struct log_head *next;
  64         int priority = 0;
  65         int ret;
  66
  67         /* bounce out if we don't have init'ed yet (regmatch etc will blow) */
  68         if (!log) {
  69                 fprintf(stderr, buf);
  70                 return;
  71         }
  72
  73         /* strip trailing newline */
  74         if (buf[size - 2] == '\n') {
  75                 buf[size - 2] = '\0';
  76                 size -= 1;
  77         }
  78
  79         /* strip the priority */
  80         ret = regexec(&pat_prio, buf, 3, matches, 0);
  81         if (!ret) {
  82                 priority = atoi(&buf[matches[1].rm_so]);
  83                 size -= matches[2].rm_so;
  84                 buf += matches[2].rm_so;
  85         }
  86
  87 #if 0
  88         /* strip kernel timestamp */
  89         ret = regexec(&pat_tstamp,buf, 4, matches, 0);
  90         if ((source == SOURCE_KLOG) && !ret) {
  91                 size -= matches[3].rm_so;
  92                 buf += matches[3].rm_so;
  93         }
  94 #endif
  95
  96         /* strip syslog timestamp */
  97         if ((source == SOURCE_SYSLOG) && (size > SYSLOG_PADDING) && (buf[SYSLOG_PADDING - 1] == ' ')) {
  98                 size -= SYSLOG_PADDING;
  99                 buf += SYSLOG_PADDING;
 100         }
 101
 102         //fprintf(stderr, "-> %d - %s\n", priority, buf);
 103
 104         /* find new oldest entry */
 105         next = log_next(newest, size);
 106         if (next > newest) {
 107                 while ((oldest > newest) && (oldest <= next) && (oldest != log))
 108                         oldest = log_next(oldest, oldest->size);
 109         } else {
 110                 //fprintf(stderr, "Log wrap\n");
 111                 newest->size = 0;
 112                 next = log_next(log, size);
 113                 for (oldest = log; oldest <= next; oldest = log_next(oldest, oldest->size))
 114                         ;
 115                 newest = log;
 116         }
 117
 118         /* add the log message */
 119         newest->size = size;
 120         newest->id = current_id++;
 121         newest->priority = priority;
 122         newest->source = source;
 123         clock_gettime(CLOCK_REALTIME, &newest->ts);
 124         strcpy(newest->data, buf);
 125
 126         ubus_notify_log(newest);
 127
 128         newest = next;
 129 }
 130
 131 static void
 132 slog_cb(struct ustream *s, int bytes)
 133 {
 134         struct ustream_buf *buf = s->r.head;
 135         char *str;
 136         int len;
 137
 138         do {
 139                 str = ustream_get_read_buf(s, NULL);
 140                 if (!str)
 141                         break;
 142                 len = strlen(buf->data);
 143                 if (!len) {
 144                         bytes -= 1;
 145                         ustream_consume(s, 1);
 146                         continue;
 147                 }
 148                 log_add(buf->data, len + 1, SOURCE_SYSLOG);
 149                 ustream_consume(s, len);
 150                 bytes -= len;
 151         } while (bytes > 0);
 152 }
 153
 154 static void
 155 klog_cb(struct ustream *s, int bytes)
 156 {
 157         struct ustream_buf *buf = s->r.head;
 158         char *newline, *str;
 159         int len;
 160
 161         do {
 162                 str = ustream_get_read_buf(s, NULL);
 163                 if (!str)
 164                         break;
 165                 newline = strchr(buf->data, '\n');
 166                 if (!newline)
 167                         break;
 168                 *newline = 0;
 169                 len = newline + 1 - str;
 170                 log_add(buf->data, len, SOURCE_KLOG);
 171                 ustream_consume(s, len);
 172         } while (1);
 173 }
 174
 175 struct ustream_fd slog = {
 176         .stream.string_data = true,
 177         .stream.notify_read = slog_cb,
 178 };
 179
 180 struct ustream_fd klog = {
 181         .stream.string_data = true,
 182         .stream.notify_read = klog_cb,
 183 };
 184
 185 static int
 186 klog_open(void)
 187 {
 188         int fd;
 189
 190         fd = open(KLOG_DEFAULT_PROC, O_RDONLY | O_NONBLOCK);
 191         if (fd < 0) {
 192                 fprintf(stderr, "Failed to open %s\n", KLOG_DEFAULT_PROC);
 193                 return -1;
 194         }
 195         fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
 196         ustream_fd_init(&klog, fd);
 197         return 0;
 198 }
 199
 200 static int
 201 syslog_open(void)
 202 {
 203         int fd;
 204
 205         unlink(log_dev);
 206         fd = usock(USOCK_UNIX | USOCK_UDP |  USOCK_SERVER | USOCK_NONBLOCK, log_dev, NULL);
 207         if (fd < 0) {
 208                 fprintf(stderr,"Failed to open %s\n", log_dev);
 209                 return -1;
 210         }
 211         chmod(log_dev, 0666);
 212         ustream_fd_init(&slog, fd);
 213         return 0;
 214 }
 215
 216 struct log_head*
 217 log_list(int count, struct log_head *h)
 218 {
 219         unsigned int min = count;
 220
 221         if (count)
 222                 min = (count < current_id) ? (current_id - count) : (0);
 223         if (!h && oldest->id >= min)
 224                 return oldest;
 225         if (!h)
 226                 h = oldest;
 227
 228         while (h != newest) {
 229                 h = log_next(h, h->size);
 230                 if (!h->size && (h > newest))
 231                         h = log;
 232                 if (h->id >= min && (h != newest))
 233                         return h;
 234         }
 235
 236         return NULL;
 237 }
 238
 239 int
 240 log_buffer_init(int size)
 241 {
 242         struct log_head *_log = malloc(size);
 243
 244         if (!_log) {
 245                 fprintf(stderr, "Failed to initialize log buffer with size %d\n", log_size);
 246                 return -1;
 247         }
 248
 249         memset(_log, 0, size);
 250
 251         if (log && ((log_size + sizeof(struct log_head)) < size)) {
 252                 struct log_head *start = _log;
 253                 struct log_head *end = ((void*) _log) + size;
 254                 struct log_head *l;
 255
 256                 l = log_list(0, NULL);
 257                 while ((start < end) && l && l->size) {
 258                         memcpy(start, l, PAD(sizeof(struct log_head) + l->size));
 259                         start = (struct log_head *) &l->data[PAD(l->size)];
 260                         l = log_list(0, l);
 261                 }
 262                 free(log);
 263                 newest = start;
 264                 newest->size = 0;
 265                 oldest = log = _log;
 266                 log_end = ((void*) log) + size;
 267         } else {
 268                 oldest = newest = log = _log;
 269                 log_end = ((void*) log) + size;
 270         }
 271         log_size = size;
 272
 273         return 0;
 274 }
 275
 276 void
 277 log_init(void)
 278 {
 279         regcomp(&pat_prio, "^<([0-9]*)>(.*)", REG_EXTENDED);
 280         regcomp(&pat_tstamp, "^\[[ 0]*([0-9]*).([0-9]*)] (.*)", REG_EXTENDED);
 281
 282         if (log_buffer_init(log_size)) {
 283                 fprintf(stderr, "Failed to allocate log memory\n");
 284                 exit(-1);
 285         }
 286
 287         syslog_open();
 288         klog_open();
 289         openlog("sysinit", LOG_CONS, LOG_DAEMON);
 290 }
 291
 292 void
 293 log_shutdown(void)
 294 {
 295         ustream_free(&slog.stream);
 296         ustream_free(&klog.stream);
 297         close(slog.fd.fd);
 298         close(klog.fd.fd);
 299 }