aboutsummaryrefslogtreecommitdiff
path: root/sysklogd/syslogd.c
blob: cc42c29426208bdadcd3e8f3cd2890016379cb7c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
/* vi: set sw=4 ts=4: */
/*
 * Mini syslogd implementation for busybox
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc.
 * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
 *
 * Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
 *
 * "circular buffer" Copyright (C) 2001 by Gennady Feldman <gfeldman@cachier.com>
 *
 * Maintainer: Gennady Feldman <gena01@cachier.com> as of Mar 12, 2001
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <paths.h>
#include <signal.h>
#include <stdarg.h>
#include <time.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/param.h>

#include "busybox.h"

/* SYSLOG_NAMES defined to pull some extra junk from syslog.h */
#define SYSLOG_NAMES
#include <sys/syslog.h>
#include <sys/uio.h>

/* Path for the file where all log messages are written */
#define __LOG_FILE "/var/log/messages"

/* Path to the unix socket */
static char lfile[BUFSIZ] = "";

static char *logFilePath = __LOG_FILE;

/* interval between marks in seconds */
static int MarkInterval = 20 * 60;

/* localhost's name */
static char LocalHostName[32];

#ifdef BB_FEATURE_REMOTE_LOG
#include <netinet/in.h>
/* udp socket for logging to remote host */
static int remotefd = -1;
/* where do we log? */
static char *RemoteHost;
/* what port to log to? */
static int RemotePort = 514;
/* To remote log or not to remote log, that is the question. */
static int doRemoteLog = FALSE;
static int local_logging = FALSE;
#endif

/* circular buffer variables/structures */
#ifdef BB_FEATURE_IPC_SYSLOG

#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>

/* our shared key */
static const long KEY_ID = 0x414e4547; /*"GENA"*/

// Semaphore operation structures
static struct shbuf_ds {
	int size;		// size of data written
	int head;		// start of message list
	int tail;		// end of message list
	char data[1];		// data/messages
} *buf = NULL;			// shared memory pointer

static struct sembuf SMwup[1] = {{1, -1, IPC_NOWAIT}}; // set SMwup
static struct sembuf SMwdn[3] = {{0, 0}, {1, 0}, {1, +1}}; // set SMwdn

static int 	shmid = -1;	// ipc shared memory id
static int 	s_semid = -1;	// ipc semaphore id
int	data_size = 16000; // data size
int	shm_size = 16000 + sizeof(*buf); // our buffer size
static int circular_logging = FALSE;

/*
 * sem_up - up()'s a semaphore.
 */
static inline void sem_up(int semid)
{
	if ( semop(semid, SMwup, 1) == -1 )
		perror_msg_and_die("semop[SMwup]");
}

/*
 * sem_down - down()'s a semaphore
 */
static inline void sem_down(int semid)
{
	if ( semop(semid, SMwdn, 2) == -1 )
		perror_msg_and_die("semop[SMwdn]");
}


void ipcsyslog_cleanup(void){
	printf("Exiting Syslogd!\n");
	if (shmid != -1)
		shmdt(buf);

	if (shmid != -1)
		shmctl(shmid, IPC_RMID, NULL);
	if (s_semid != -1)
		semctl(s_semid, 0, IPC_RMID, 0);
}

void ipcsyslog_init(void){
	if (buf == NULL){
	    if ((shmid = shmget(KEY_ID, shm_size, IPC_CREAT | 1023)) == -1)
		    	perror_msg_and_die("shmget");


	    if ((buf = shmat(shmid, NULL, 0)) == NULL)
    			perror_msg_and_die("shmat");


	    buf->size=data_size;
	    buf->head=buf->tail=0;

	    // we'll trust the OS to set initial semval to 0 (let's hope)
	    if ((s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023)) == -1){
	    	if (errno == EEXIST){
		   if ((s_semid = semget(KEY_ID, 2, 0)) == -1)
		    perror_msg_and_die("semget");
		}else
    			perror_msg_and_die("semget");
	    }
	}else{
		printf("Buffer already allocated just grab the semaphore?");
	}
}

/* write message to buffer */
void circ_message(const char *msg){
	int l=strlen(msg)+1; /* count the whole message w/ '\0' included */

	sem_down(s_semid);

	/*
	 * Circular Buffer Algorithm:
	 * --------------------------
	 *
	 * Start-off w/ empty buffer of specific size SHM_SIZ
	 * Start filling it up w/ messages. I use '\0' as separator to break up messages.
	 * This is also very handy since we can do printf on message.
	 *
	 * Once the buffer is full we need to get rid of the first message in buffer and
	 * insert the new message. (Note: if the message being added is >1 message then
	 * we will need to "remove" >1 old message from the buffer). The way this is done
	 * is the following:
	 *	When we reach the end of the buffer we set a mark and start from the beginning.
	 *	Now what about the beginning and end of the buffer? Well we have the "head"
	 *	index/pointer which is the starting point for the messages and we have "tail"
	 *	index/pointer which is the ending point for the messages. When we "display" the
	 *	messages we start from the beginning and continue until we reach "tail". If we
	 *	reach end of buffer, then we just start from the beginning (offset 0). "head" and
	 *	"tail" are actually offsets from the beginning of the buffer.
	 *
	 * Note: This algorithm uses Linux IPC mechanism w/ shared memory and semaphores to provide
	 * 	 a threasafe way of handling shared memory operations.
	 */
	if ( (buf->tail + l) < buf->size ){
		/* before we append the message we need to check the HEAD so that we won't
		   overwrite any of the message that we still need and adjust HEAD to point
		   to the next message! */
		if ( buf->tail < buf->head){
			if ( (buf->tail + l) >= buf->head ){
			  /* we need to move the HEAD to point to the next message
			   * Theoretically we have enough room to add the whole message to the
			   * buffer, because of the first outer IF statement, so we don't have
			   * to worry about overflows here!
			   */
			   int k= buf->tail + l - buf->head; /* we need to know how many bytes
			   					we are overwriting to make
								enough room */
			   char *c=memchr(buf->data+buf->head + k,'\0',buf->size - (buf->head + k));
			   if (c != NULL) {/* do a sanity check just in case! */
			   	buf->head = c - buf->data + 1; /* we need to convert pointer to
								  offset + skip the '\0' since
								  we need to point to the beginning
								  of the next message */
				/* Note: HEAD is only used to "retrieve" messages, it's not used
					when writing messages into our buffer */
			   }else{ /* show an error message to know we messed up? */
			   	printf("Weird! Can't find the terminator token??? \n");
			   	buf->head=0;
			   }
			}
		} /* in other cases no overflows have been done yet, so we don't care! */

		/* we should be ok to append the message now */
		strncpy(buf->data + buf->tail,msg,l); /* append our message */
		buf->tail+=l; /* count full message w/ '\0' terminating char */
	}else{
		/* we need to break up the message and "circle" it around */
		char *c;
		int k=buf->tail + l - buf->size; /* count # of bytes we don't fit */
		
		/* We need to move HEAD! This is always the case since we are going
		 * to "circle" the message.
		 */
		c=memchr(buf->data + k ,'\0', buf->size - k);
		
		if (c != NULL) /* if we don't have '\0'??? weird!!! */{
			/* move head pointer*/
			buf->head=c-buf->data+1; 
			
			/* now write the first part of the message */			
			strncpy(buf->data + buf->tail, msg, l - k - 1);
			
			/* ALWAYS terminate end of buffer w/ '\0' */
			buf->data[buf->size-1]='\0'; 
			
			/* now write out the rest of the string to the beginning of the buffer */
			strcpy(buf->data, &msg[l-k-1]);

			/* we need to place the TAIL at the end of the message */
			buf->tail = k + 1;
		}else{
			printf("Weird! Can't find the terminator token from the beginning??? \n");
			buf->head = buf->tail = 0; /* reset buffer, since it's probably corrupted */
		}
		
	}
	sem_up(s_semid);
}
#endif
/* Note: There is also a function called "message()" in init.c */
/* Print a message to the log file. */
static void message (char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
static void message (char *fmt, ...)
{
	int fd;
	struct flock fl;
	va_list arguments;

	fl.l_whence = SEEK_SET;
	fl.l_start  = 0;
	fl.l_len    = 1;

#ifdef BB_FEATURE_IPC_SYSLOG
	if ((circular_logging == TRUE) && (buf != NULL)){
			char b[1024];
			va_start (arguments, fmt);
			vsprintf (b, fmt, arguments);
			va_end (arguments);
			circ_message(b);

	}else
#endif
	if ((fd = device_open (logFilePath,
						   O_WRONLY | O_CREAT | O_NOCTTY | O_APPEND |
						   O_NONBLOCK)) >= 0) {
		fl.l_type = F_WRLCK;
		fcntl (fd, F_SETLKW, &fl);
		va_start (arguments, fmt);
		vdprintf (fd, fmt, arguments);
		va_end (arguments);
		fl.l_type = F_UNLCK;
		fcntl (fd, F_SETLKW, &fl);
		close (fd);
	} else {
		/* Always send console messages to /dev/console so people will see them. */
		if ((fd = device_open (_PATH_CONSOLE,
							   O_WRONLY | O_NOCTTY | O_NONBLOCK)) >= 0) {
			va_start (arguments, fmt);
			vdprintf (fd, fmt, arguments);
			va_end (arguments);
			close (fd);
		} else {
			fprintf (stderr, "Bummer, can't print: ");
			va_start (arguments, fmt);
			vfprintf (stderr, fmt, arguments);
			fflush (stderr);
			va_end (arguments);
		}
	}
}

static void logMessage (int pri, char *msg)
{
	time_t now;
	char *timestamp;
	static char res[20] = "";
	CODE *c_pri, *c_fac;

	if (pri != 0) {
		for (c_fac = facilitynames;
				c_fac->c_name && !(c_fac->c_val == LOG_FAC(pri) << 3); c_fac++);
		for (c_pri = prioritynames;
				c_pri->c_name && !(c_pri->c_val == LOG_PRI(pri)); c_pri++);
		if (c_fac->c_name == NULL || c_pri->c_name == NULL)
			snprintf(res, sizeof(res), "<%d>", pri);
		else
			snprintf(res, sizeof(res), "%s.%s", c_fac->c_name, c_pri->c_name);
	}

	if (strlen(msg) < 16 || msg[3] != ' ' || msg[6] != ' ' ||
			msg[9] != ':' || msg[12] != ':' || msg[15] != ' ') {
		time(&now);
		timestamp = ctime(&now) + 4;
		timestamp[15] = '\0';
	} else {
		timestamp = msg;
		timestamp[15] = '\0';
		msg += 16;
	}

	/* todo: supress duplicates */

#ifdef BB_FEATURE_REMOTE_LOG
	/* send message to remote logger */
	if ( -1 != remotefd){
static const int IOV_COUNT = 2;
		struct iovec iov[IOV_COUNT];
		struct iovec *v = iov;

		bzero(&res, sizeof(res));
		snprintf(res, sizeof(res), "<%d>", pri);
		v->iov_base = res ;
		v->iov_len = strlen(res);          
		v++;

		v->iov_base = msg;
		v->iov_len = strlen(msg);          

		if ( -1 == writev(remotefd,iov, IOV_COUNT)){
			error_msg_and_die("syslogd: cannot write to remote file handle on" 
					"%s:%d",RemoteHost,RemotePort);
		}
	}
	if (local_logging == TRUE)
#endif
		/* now spew out the message to wherever it is supposed to go */
		message("%s %s %s %s\n", timestamp, LocalHostName, res, msg);


}

static void quit_signal(int sig)
{
	logMessage(0, "System log daemon exiting.");
	unlink(lfile);
#ifdef BB_FEATURE_IPC_SYSLOG
	ipcsyslog_cleanup();
#endif

	exit(TRUE);
}

static void domark(int sig)
{
	if (MarkInterval > 0) {
		logMessage(LOG_SYSLOG | LOG_INFO, "-- MARK --");
		alarm(MarkInterval);
	}
}

static const int BUFSIZE = 1023;
static int serveConnection (int conn)
{
	RESERVE_BB_BUFFER(tmpbuf, BUFSIZE + 1);
	int    n_read;

	n_read = read (conn, tmpbuf, BUFSIZE );

	if (n_read > 0) {

		int           pri = (LOG_USER | LOG_NOTICE);
		char          line[ BUFSIZE + 1 ];
		unsigned char c;

		char *p = tmpbuf, *q = line;

		tmpbuf[ n_read - 1 ] = '\0';

		while (p && (c = *p) && q < &line[ sizeof (line) - 1 ]) {
			if (c == '<') {
			/* Parse the magic priority number. */
				pri = 0;
				while (isdigit (*(++p))) {
					pri = 10 * pri + (*p - '0');
				}
				if (pri & ~(LOG_FACMASK | LOG_PRIMASK)){
					pri = (LOG_USER | LOG_NOTICE);
				}
			} else if (c == '\n') {
				*q++ = ' ';
			} else if (iscntrl (c) && (c < 0177)) {
				*q++ = '^';
				*q++ = c ^ 0100;
			} else {
				*q++ = c;
			}
			p++;
		}
		*q = '\0';
		/* Now log it */
		logMessage (pri, line);
	}
	return n_read;
}


#ifdef BB_FEATURE_REMOTE_LOG
static void init_RemoteLog (void){

  struct sockaddr_in remoteaddr;
  struct hostent *hostinfo;
  int len = sizeof(remoteaddr);

  bzero(&remoteaddr, len);

  remotefd = socket(AF_INET, SOCK_DGRAM, 0);

  if (remotefd < 0) {
    error_msg_and_die("syslogd: cannot create socket");
  }

  hostinfo = (struct hostent *) gethostbyname(RemoteHost);

  if (!hostinfo) {
    error_msg_and_die("syslogd: cannot resolve remote host name [%s]", RemoteHost);
  }

  remoteaddr.sin_family = AF_INET;
  remoteaddr.sin_addr = *(struct in_addr *) *hostinfo->h_addr_list;
  remoteaddr.sin_port = htons(RemotePort);

  /* 
     Since we are using UDP sockets, connect just sets the default host and port 
     for future operations
  */
  if ( 0 != (connect(remotefd, (struct sockaddr *) &remoteaddr, len))){
    error_msg_and_die("syslogd: cannot connect to remote host %s:%d", RemoteHost, RemotePort);
  }

}
#endif

static void doSyslogd (void) __attribute__ ((noreturn));
static void doSyslogd (void)
{
	struct sockaddr_un sunx;
	socklen_t addrLength;


	int sock_fd;
	fd_set fds;

	/* Set up signal handlers. */
	signal (SIGINT,  quit_signal);
	signal (SIGTERM, quit_signal);
	signal (SIGQUIT, quit_signal);
	signal (SIGHUP,  SIG_IGN);
	signal (SIGCHLD,  SIG_IGN);
#ifdef SIGCLD
	signal (SIGCLD,  SIG_IGN);
#endif
	signal (SIGALRM, domark);
	alarm (MarkInterval);

	/* Create the syslog file so realpath() can work. */
	close (open (_PATH_LOG, O_RDWR | O_CREAT, 0644));
	if (realpath (_PATH_LOG, lfile) == NULL)
		perror_msg_and_die ("Could not resolve path to " _PATH_LOG);

	unlink (lfile);

	memset (&sunx, 0, sizeof (sunx));
	sunx.sun_family = AF_UNIX;
	strncpy (sunx.sun_path, lfile, sizeof (sunx.sun_path));
	if ((sock_fd = socket (AF_UNIX, SOCK_STREAM, 0)) < 0)
		perror_msg_and_die ("Couldn't obtain descriptor for socket " _PATH_LOG);

	addrLength = sizeof (sunx.sun_family) + strlen (sunx.sun_path);
	if ((bind (sock_fd, (struct sockaddr *) &sunx, addrLength)) || (listen (sock_fd, 5)))
		perror_msg_and_die ("Could not connect to socket " _PATH_LOG);

	if (chmod (lfile, 0666) < 0)
		perror_msg_and_die ("Could not set permission on " _PATH_LOG);

	FD_ZERO (&fds);
	FD_SET (sock_fd, &fds);

        #ifdef BB_FEATURE_REMOTE_LOG
        if (doRemoteLog == TRUE){
          init_RemoteLog();
        }
        #endif

	logMessage (0, "syslogd started: BusyBox v" BB_VER " (" BB_BT ")");

	for (;;) {

		fd_set readfds;
		int    n_ready;
		int    fd;

		memcpy (&readfds, &fds, sizeof (fds));

		if ((n_ready = select (FD_SETSIZE, &readfds, NULL, NULL, NULL)) < 0) {
			if (errno == EINTR) continue; /* alarm may have happened. */
			perror_msg_and_die ("select error");
		}

		for (fd = 0; (n_ready > 0) && (fd < FD_SETSIZE); fd++) {
			if (FD_ISSET (fd, &readfds)) {

				--n_ready;

				if (fd == sock_fd) {
					int   conn;

					//printf("New Connection request.\n");
					if ((conn = accept (sock_fd, (struct sockaddr *) &sunx, &addrLength)) < 0) {
						perror_msg_and_die ("accept error");
					}

					FD_SET(conn, &fds);
					//printf("conn: %i, set_size: %i\n",conn,FD_SETSIZE);
			  	} else {
					//printf("Serving connection: %i\n",fd);
					  if ( serveConnection(fd) <= 0 ) {
					    close (fd);
					    FD_CLR(fd, &fds);
            }
				} /* fd == sock_fd */
			}/* FD_ISSET() */
		}/* for */
	} /* for main loop */
}

static void daemon_init (char **argv, char *dz, void fn (void))
{
	setsid();
	chdir ("/");
	strncpy(argv[0], dz, strlen(argv[0]));
	fn();
	exit(0);
}

extern int syslogd_main(int argc, char **argv)
{
	int opt, pid;
	int doFork = TRUE;

	char *p;

	/* do normal option parsing */
	while ((opt = getopt(argc, argv, "m:nO:R:LC")) > 0) {
		switch (opt) {
			case 'm':
				MarkInterval = atoi(optarg) * 60;
				break;
			case 'n':
				doFork = FALSE;
				break;
			case 'O':
				logFilePath = strdup(optarg);
				break;
#ifdef BB_FEATURE_REMOTE_LOG
			case 'R':
				RemoteHost = strdup(optarg);
				if ( (p = strchr(RemoteHost, ':'))){
					RemotePort = atoi(p+1);
					*p = '\0';
				}
				doRemoteLog = TRUE;
				break;
			case 'L':
				local_logging = TRUE;
				break;
#endif
#ifdef BB_FEATURE_IPC_SYSLOG
			case 'C':
				circular_logging = TRUE;
				break;
#endif
			default:
				show_usage();
		}
	}

#ifdef BB_FEATURE_REMOTE_LOG
	/* If they have not specified remote logging, then log locally */
	if (doRemoteLog == FALSE)
		local_logging = TRUE;
#endif


	/* Store away localhost's name before the fork */
	gethostname(LocalHostName, sizeof(LocalHostName));
	if ((p = strchr(LocalHostName, '.'))) {
		*p++ = '\0';
	}

	umask(0);

#ifdef BB_FEATURE_IPC_SYSLOG
	if (circular_logging == TRUE ){
 	   ipcsyslog_init();
	}
#endif

	if (doFork == TRUE) {
		pid = fork();
		if (pid < 0)
			exit(pid);
		else if (pid == 0) {
			daemon_init (argv, "syslogd", doSyslogd);
		}
	} else {
		doSyslogd();
	}

	return EXIT_SUCCESS;
}

/*
Local Variables
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/