1/* syslogd.c - a system logging utility.
2 *
3 * Copyright 2013 Madhur Verma <mad.flexi@gmail.com>
4 * Copyright 2013 Kyungwan Han <asura321@gmail.com>
5 *
6 * No Standard
7
8USE_SYSLOGD(NEWTOY(syslogd,">0l#<1>8=8R:b#<0>99=1s#<0=200m#<0>71582787=20O:p:f:a:nSKLD", TOYFLAG_SBIN|TOYFLAG_STAYROOT))
9
10config SYSLOGD
11  bool "syslogd"
12  default n
13  help
14  usage: syslogd  [-a socket] [-O logfile] [-f config file] [-m interval]
15                  [-p socket] [-s SIZE] [-b N] [-R HOST] [-l N] [-nSLKD]
16
17  System logging utility
18
19  -a      Extra unix socket for listen
20  -O FILE Default log file <DEFAULT: /var/log/messages>
21  -f FILE Config file <DEFAULT: /etc/syslog.conf>
22  -p      Alternative unix domain socket <DEFAULT : /dev/log>
23  -n      Avoid auto-backgrounding
24  -S      Smaller output
25  -m MARK interval <DEFAULT: 20 minutes> (RANGE: 0 to 71582787)
26  -R HOST Log to IP or hostname on PORT (default PORT=514/UDP)"
27  -L      Log locally and via network (default is network only if -R)"
28  -s SIZE Max size (KB) before rotation (default:200KB, 0=off)
29  -b N    rotated logs to keep (default:1, max=99, 0=purge)
30  -K      Log to kernel printk buffer (use dmesg to read it)
31  -l N    Log only messages more urgent than prio(default:8 max:8 min:1)
32  -D      Drop duplicates
33*/
34
35#define FOR_syslogd
36#include "toys.h"
37
38// UNIX Sockets for listening
39struct unsocks {
40  struct unsocks *next;
41  char *path;
42  struct sockaddr_un sdu;
43  int sd;
44};
45
46// Log file entry to log into.
47struct logfile {
48  struct logfile *next;
49  char *filename;
50  uint32_t facility[8];
51  uint8_t level[LOG_NFACILITIES];
52  int logfd;
53  struct sockaddr_in saddr;
54};
55
56GLOBALS(
57  char *socket;
58  char *config_file;
59  char *unix_socket;
60  char *logfile;
61  long interval;
62  long rot_size;
63  long rot_count;
64  char *remote_log;
65  long log_prio;
66
67  struct unsocks *lsocks;  // list of listen sockets
68  struct logfile *lfiles;  // list of write logfiles
69  int sigfd[2];
70)
71
72// Lookup numerical code from name
73// Also used in logger
74int logger_lookup(int where, char *key)
75{
76  CODE *w = ((CODE *[]){facilitynames, prioritynames})[where];
77
78  for (; w->c_name; w++)
79    if (!strcasecmp(key, w->c_name)) return w->c_val;
80
81  return -1;
82}
83
84//search the given name and return its value
85static char *dec(int val, CODE *clist, char *buf)
86{
87  for (; clist->c_name; clist++)
88    if (val == clist->c_val) return clist->c_name;
89  sprintf(buf, "%u", val);
90
91  return buf;
92}
93
94/*
95 * recurses the logfile list and resolves config
96 * for evry file and updates facilty and log level bits.
97 */
98static int resolve_config(struct logfile *file, char *config)
99{
100  char *tk;
101
102  for (tk = strtok(config, "; \0"); tk; tk = strtok(NULL, "; \0")) {
103    char *fac = tk, *lvl;
104    int i = 0;
105    unsigned facval = 0;
106    uint8_t set, levval, bits = 0;
107
108    tk = strchr(fac, '.');
109    if (!tk) return -1;
110    *tk = '\0';
111    lvl = tk + 1;
112
113    for (;;) {
114      char *nfac = strchr(fac, ',');
115
116      if (nfac) *nfac = '\0';
117      if (*fac == '*') {
118        facval = 0xFFFFFFFF;
119        if (fac[1]) return -1;
120      } else {
121        if ((i = logger_lookup(0, fac)) == -1) return -1;
122        facval |= (1 << LOG_FAC(i));
123      }
124      if (nfac) fac = nfac + 1;
125      else break;
126    }
127
128    levval = 0;
129    for (tk = "!=*"; *tk; tk++, bits <<= 1) {
130      if (*lvl == *tk) {
131        bits++;
132        lvl++;
133      }
134    }
135    if (bits & 2) levval = 0xff;
136    if (*lvl) {
137      if ((i = logger_lookup(1, lvl)) == -1) return -1;
138      levval |= (bits & 4) ? LOG_MASK(i) : LOG_UPTO(i);
139      if (bits & 8) levval = ~levval;
140    }
141
142    for (i = 0, set = levval; set; set >>= 1, i++)
143      if (set & 0x1) file->facility[i] |= ~facval;
144    for (i = 0; i < LOG_NFACILITIES; facval >>= 1, i++)
145      if (facval & 0x1) file->level[i] |= ~levval;
146  }
147
148  return 0;
149}
150
151// Parse config file and update the log file list.
152static int parse_config_file(void)
153{
154  struct logfile *file;
155  FILE *fp;
156  char *confline, *tk[2];
157  int len, lineno = 0;
158  size_t linelen;
159  /*
160   * if -K then open only /dev/kmsg
161   * all other log files are neglected
162   * thus no need to open config either.
163   */
164  if (toys.optflags & FLAG_K) {
165    file = xzalloc(sizeof(struct logfile));
166    file->filename = xstrdup("/dev/kmsg");
167    TT.lfiles = file;
168    return 0;
169  }
170  /*
171   * if -R then add remote host to log list
172   * if -L is not provided all other log
173   * files are neglected thus no need to
174   * open config either so just return.
175   */
176  if (toys.optflags & FLAG_R) {
177    file = xzalloc(sizeof(struct logfile));
178    file->filename = xmprintf("@%s",TT.remote_log);
179    TT.lfiles = file;
180    if (!(toys.optflags & FLAG_L)) return 0;
181  }
182  /*
183   * Read config file and add logfiles to the list
184   * with their configuration.
185   */
186  if (!(fp = fopen(TT.config_file, "r")) && (toys.optflags & FLAG_f))
187    perror_exit("can't open '%s'", TT.config_file);
188
189  for (linelen = 0; fp;) {
190    confline = NULL;
191    len = getline(&confline, &linelen, fp);
192    if (len <= 0) break;
193    lineno++;
194    for (; *confline == ' '; confline++, len--) ;
195    if ((confline[0] == '#') || (confline[0] == '\n')) continue;
196    tk[0] = confline;
197    for (; len && !(*tk[0]==' ' || *tk[0]=='\t'); tk[0]++, len--);
198    for (tk[1] = tk[0]; len && (*tk[1]==' ' || *tk[1]=='\t'); tk[1]++, len--);
199    if (!len || (len == 1 && *tk[1] == '\n')) {
200      error_msg("error in '%s' at line %d", TT.config_file, lineno);
201      return -1;
202    }
203    else if (*(tk[1] + len - 1) == '\n') *(tk[1] + len - 1) = '\0';
204    *tk[0] = '\0';
205    if (*tk[1] != '*') {
206      file = TT.lfiles;
207      while (file && strcmp(file->filename, tk[1])) file = file->next;
208      if (!file) {
209        file = xzalloc(sizeof(struct logfile));
210        file->filename = xstrdup(tk[1]);
211        file->next = TT.lfiles;
212        TT.lfiles = file;
213      }
214      if (resolve_config(file, confline) == -1) {
215        error_msg("error in '%s' at line %d", TT.config_file, lineno);
216        return -1;
217      }
218    }
219    free(confline);
220  }
221  /*
222   * Can't open config file or support is not enabled
223   * adding default logfile to the head of list.
224   */
225  if (!fp){
226    file = xzalloc(sizeof(struct logfile));
227    file->filename = xstrdup((toys.optflags & FLAG_O) ?
228                     TT.logfile : "/var/log/messages"); //DEFLOGFILE
229    file->next = TT.lfiles;
230    TT.lfiles = file;
231  } else fclose(fp);
232  return 0;
233}
234
235// open every log file in list.
236static void open_logfiles(void)
237{
238  struct logfile *tfd;
239
240  for (tfd = TT.lfiles; tfd; tfd = tfd->next) {
241    char *p, *tmpfile;
242    long port = 514;
243
244    if (*tfd->filename == '@') { // network
245      struct addrinfo *info, rp;
246
247      tmpfile = xstrdup(tfd->filename + 1);
248      if ((p = strchr(tmpfile, ':'))) {
249        char *endptr;
250
251        *p = '\0';
252        port = strtol(++p, &endptr, 10);
253        if (*endptr || endptr == p || port < 0 || port > 65535)
254          error_exit("bad port in %s", tfd->filename);
255      }
256      memset(&rp, 0, sizeof(rp));
257      rp.ai_family = AF_INET;
258      rp.ai_socktype = SOCK_DGRAM;
259      rp.ai_protocol = IPPROTO_UDP;
260
261      if (getaddrinfo(tmpfile, NULL, &rp, &info) || !info)
262        perror_exit("BAD ADDRESS: can't find : %s ", tmpfile);
263      ((struct sockaddr_in*)info->ai_addr)->sin_port = htons(port);
264      memcpy(&tfd->saddr, info->ai_addr, info->ai_addrlen);
265      freeaddrinfo(info);
266
267      tfd->logfd = xsocket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
268      free(tmpfile);
269    } else tfd->logfd = open(tfd->filename, O_CREAT | O_WRONLY | O_APPEND, 0666);
270    if (tfd->logfd < 0) {
271      tfd->filename = "/dev/console";
272      tfd->logfd = open(tfd->filename, O_APPEND);
273    }
274  }
275}
276
277//write to file with rotation
278static int write_rotate(struct logfile *tf, int len)
279{
280  int size, isreg;
281  struct stat statf;
282  isreg = (!fstat(tf->logfd, &statf) && S_ISREG(statf.st_mode));
283  size = statf.st_size;
284
285  if ((toys.optflags & FLAG_s) || (toys.optflags & FLAG_b)) {
286    if (TT.rot_size && isreg && (size + len) > (TT.rot_size*1024)) {
287      if (TT.rot_count) { /* always 0..99 */
288        int i = strlen(tf->filename) + 3 + 1;
289        char old_file[i];
290        char new_file[i];
291        i = TT.rot_count - 1;
292        while (1) {
293          sprintf(new_file, "%s.%d", tf->filename, i);
294          if (!i) break;
295          sprintf(old_file, "%s.%d", tf->filename, --i);
296          rename(old_file, new_file);
297        }
298        rename(tf->filename, new_file);
299        unlink(tf->filename);
300        close(tf->logfd);
301        tf->logfd = open(tf->filename, O_CREAT | O_WRONLY | O_APPEND, 0666);
302        if (tf->logfd < 0) {
303          perror_msg("can't open %s", tf->filename);
304          return -1;
305        }
306      }
307      ftruncate(tf->logfd, 0);
308    }
309  }
310  return write(tf->logfd, toybuf, len);
311}
312
313//Parse messege and write to file.
314static void logmsg(char *msg, int len)
315{
316  time_t now;
317  char *p, *ts, *lvlstr, *facstr;
318  struct utsname uts;
319  int pri = 0;
320  struct logfile *tf = TT.lfiles;
321
322  char *omsg = msg;
323  int olen = len, fac, lvl;
324
325  if (*msg == '<') { // Extract the priority no.
326    pri = (int) strtoul(msg + 1, &p, 10);
327    if (*p == '>') msg = p + 1;
328  }
329  /* Jan 18 00:11:22 msg...
330   * 01234567890123456
331   */
332  if (len < 16 || msg[3] != ' ' || msg[6] != ' ' || msg[9] != ':'
333      || msg[12] != ':' || msg[15] != ' ') {
334    time(&now);
335    ts = ctime(&now) + 4; /* skip day of week */
336  } else {
337    now = 0;
338    ts = msg;
339    msg += 16;
340  }
341  ts[15] = '\0';
342  fac = LOG_FAC(pri);
343  lvl = LOG_PRI(pri);
344
345  if (toys.optflags & FLAG_K) len = sprintf(toybuf, "<%d> %s\n", pri, msg);
346  else {
347    char facbuf[12], pribuf[12];
348
349    facstr = dec(pri & LOG_FACMASK, facilitynames, facbuf);
350    lvlstr = dec(LOG_PRI(pri), prioritynames, pribuf);
351
352    p = "local";
353    if (!uname(&uts)) p = uts.nodename;
354    if (toys.optflags & FLAG_S) len = sprintf(toybuf, "%s %s\n", ts, msg);
355    else len = sprintf(toybuf, "%s %s %s.%s %s\n", ts, p, facstr, lvlstr, msg);
356  }
357  if (lvl >= TT.log_prio) return;
358
359  for (; tf; tf = tf->next) {
360    if (tf->logfd > 0) {
361      if (!((tf->facility[lvl] & (1 << fac)) || (tf->level[fac] & (1<<lvl)))) {
362        int wlen, isNetwork = *tf->filename == '@';
363        if (isNetwork)
364          wlen = sendto(tf->logfd, omsg, olen, 0, (struct sockaddr*)&tf->saddr, sizeof(tf->saddr));
365        else wlen = write_rotate(tf, len);
366        if (wlen < 0) perror_msg("write failed file : %s ", tf->filename + isNetwork);
367      }
368    }
369  }
370}
371
372/*
373 * closes all read and write fds
374 * and frees all nodes and lists
375 */
376static void cleanup(void)
377{
378  while (TT.lsocks) {
379    struct unsocks *fnode = TT.lsocks;
380
381    if (fnode->sd >= 0) {
382      close(fnode->sd);
383      unlink(fnode->path);
384    }
385    TT.lsocks = fnode->next;
386    free(fnode);
387  }
388
389  while (TT.lfiles) {
390    struct logfile *fnode = TT.lfiles;
391
392    free(fnode->filename);
393    if (fnode->logfd >= 0) close(fnode->logfd);
394    TT.lfiles = fnode->next;
395    free(fnode);
396  }
397}
398
399static void signal_handler(int sig)
400{
401  unsigned char ch = sig;
402  if (write(TT.sigfd[1], &ch, 1) != 1) error_msg("can't send signal");
403}
404
405void syslogd_main(void)
406{
407  struct unsocks *tsd;
408  int nfds, retval, last_len=0;
409  struct timeval tv;
410  fd_set rfds;        // fds for reading
411  char *temp, *buffer = (toybuf +2048), *last_buf = (toybuf + 3072); //these two buffs are of 1K each
412
413  if ((toys.optflags & FLAG_p) && (strlen(TT.unix_socket) > 108))
414    error_exit("Socket path should not be more than 108");
415
416  TT.config_file = (toys.optflags & FLAG_f) ?
417                   TT.config_file : "/etc/syslog.conf"; //DEFCONFFILE
418init_jumpin:
419  tsd = xzalloc(sizeof(struct unsocks));
420
421  tsd->path = (toys.optflags & FLAG_p) ? TT.unix_socket : "/dev/log"; // DEFLOGSOCK
422  TT.lsocks = tsd;
423
424  if (toys.optflags & FLAG_a) {
425    for (temp = strtok(TT.socket, ":"); temp; temp = strtok(NULL, ":")) {
426      if (strlen(temp) > 107) temp[108] = '\0';
427      tsd = xzalloc(sizeof(struct unsocks));
428      tsd->path = temp;
429      tsd->next = TT.lsocks;
430      TT.lsocks = tsd;
431    }
432  }
433  /*
434   * initializes unsock_t structure
435   * and opens socket for reading
436   * and adds to global lsock list.
437  */
438  nfds = 0;
439  for (tsd = TT.lsocks; tsd; tsd = tsd->next) {
440    tsd->sdu.sun_family = AF_UNIX;
441    strcpy(tsd->sdu.sun_path, tsd->path);
442    tsd->sd = socket(AF_UNIX, SOCK_DGRAM, 0);
443    if (tsd->sd < 0) {
444      perror_msg("OPEN SOCKS : failed");
445      continue;
446    }
447    unlink(tsd->sdu.sun_path);
448    if (bind(tsd->sd, (struct sockaddr *) &tsd->sdu, sizeof(tsd->sdu))) {
449      perror_msg("BIND SOCKS : failed sock : %s", tsd->sdu.sun_path);
450      close(tsd->sd);
451      continue;
452    }
453    chmod(tsd->path, 0777);
454    nfds++;
455  }
456  if (!nfds) {
457    error_msg("Can't open single socket for listenning.");
458    goto clean_and_exit;
459  }
460
461  // Setup signals
462  xpipe(TT.sigfd);
463
464  fcntl(TT.sigfd[1] , F_SETFD, FD_CLOEXEC);
465  fcntl(TT.sigfd[0] , F_SETFD, FD_CLOEXEC);
466  int flags = fcntl(TT.sigfd[1], F_GETFL);
467  fcntl(TT.sigfd[1], F_SETFL, flags | O_NONBLOCK);
468  signal(SIGHUP, signal_handler);
469  signal(SIGTERM, signal_handler);
470  signal(SIGINT, signal_handler);
471  signal(SIGQUIT, signal_handler);
472
473  if (parse_config_file() == -1) goto clean_and_exit;
474  open_logfiles();
475  if (!(toys.optflags & FLAG_n)) {
476    daemon(0, 0);
477    //don't daemonize again if SIGHUP received.
478    toys.optflags |= FLAG_n;
479  }
480  xpidfile("syslogd");
481
482  logmsg("<46>Toybox: syslogd started", 27); //27 : the length of message
483  for (;;) {
484    // Add opened socks to rfds for select()
485    FD_ZERO(&rfds);
486    for (tsd = TT.lsocks; tsd; tsd = tsd->next) FD_SET(tsd->sd, &rfds);
487    FD_SET(TT.sigfd[0], &rfds);
488    tv.tv_usec = 0;
489    tv.tv_sec = TT.interval*60;
490
491    retval = select(TT.sigfd[0] + 1, &rfds, NULL, NULL, (TT.interval)?&tv:NULL);
492    if (retval < 0) {
493      if (errno != EINTR) perror_msg("Error in select ");
494    }
495    else if (!retval) logmsg("<46>-- MARK --", 14);
496    else if (FD_ISSET(TT.sigfd[0], &rfds)) { /* May be a signal */
497      unsigned char sig;
498
499      if (read(TT.sigfd[0], &sig, 1) != 1) {
500        error_msg("signal read failed.\n");
501        continue;
502      }
503      switch(sig) {
504        case SIGTERM:    /* FALLTHROUGH */
505        case SIGINT:     /* FALLTHROUGH */
506        case SIGQUIT:
507          logmsg("<46>syslogd exiting", 19);
508          if (CFG_TOYBOX_FREE ) cleanup();
509          signal(sig, SIG_DFL);
510          sigset_t ss;
511          sigemptyset(&ss);
512          sigaddset(&ss, sig);
513          sigprocmask(SIG_UNBLOCK, &ss, NULL);
514          raise(sig);
515          _exit(1);  /* Should not reach it */
516          break;
517        case SIGHUP:
518          logmsg("<46>syslogd exiting", 19);
519          cleanup(); //cleanup is done, as we restart syslog.
520          goto init_jumpin;
521        default: break;
522      }
523    } else { /* Some activity on listen sockets. */
524      for (tsd = TT.lsocks; tsd; tsd = tsd->next) {
525        int sd = tsd->sd;
526        if (FD_ISSET(sd, &rfds)) {
527          int len = read(sd, buffer, 1023); //buffer is of 1K, hence readingonly 1023 bytes, 1 for NUL
528          if (len > 0) {
529            buffer[len] = '\0';
530            if((toys.optflags & FLAG_D) && (len == last_len))
531              if (!memcmp(last_buf, buffer, len)) break;
532
533            memcpy(last_buf, buffer, len);
534            last_len = len;
535            logmsg(buffer, len);
536          }
537          break;
538        }
539      }
540    }
541  }
542clean_and_exit:
543  logmsg("<46>syslogd exiting", 19);
544  if (CFG_TOYBOX_FREE ) cleanup();
545}
546