busybox/sysklogd/syslogd.c

/* vi: set sw=4 ts=4: */
/*
 * Mini syslogd implementation for busybox
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 *
 * Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
 *
 * "circular buffer" Copyright (C) 2001 by Gennady Feldman <gfeldman@gena01.com>
 *
 * Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "busybox.h"
#include <paths.h>
#include <sys/un.h>

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

#define DEBUG 0

/* Path to the unix socket */
static char *dev_log_name;

/* Path for the file where all log messages are written */
static const char *logFilePath = "/var/log/messages";
static int logFD = -1;

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

/* level of messages to be locally logged */
static int logLevel = 8;

/* localhost's name */
static char localHostName[64];

#if ENABLE_FEATURE_ROTATE_LOGFILE
/* max size of message file before being rotated */
static unsigned logFileSize = 200 * 1024;
/* number of rotated message files */
static unsigned logFileRotate = 1;
static unsigned curFileSize;
static smallint isRegular;
#endif

#if ENABLE_FEATURE_REMOTE_LOG
#include <netinet/in.h>
/* udp socket for logging to remote host */
static int remoteFD = -1;
static len_and_sockaddr* remoteAddr;
#endif

/* We are using bb_common_bufsiz1 for buffering: */
enum { MAX_READ = (BUFSIZ/6) & ~0xf };
/* We recv into RECVBUF... (size: MAX_READ ~== BUFSIZ/6) */
#define RECVBUF  bb_common_bufsiz1
/* ...then copy to PARSEBUF, escaping control chars */
/* (can grow x2 max ~== BUFSIZ/3) */
#define PARSEBUF (bb_common_bufsiz1 + MAX_READ)
/* ...then sprintf into PRINTBUF, adding timestamp (15 chars),
 * host (64), fac.prio (20) to the message */
/* (growth by: 15 + 64 + 20 + delims = ~110) */
#define PRINTBUF (bb_common_bufsiz1 + 3*MAX_READ)
/* totals: BUFSIZ == BUFSIZ/6 + BUFSIZ/3 + (BUFSIZ/3+BUFSIZ/6)
 * -- we have BUFSIZ/6 extra at the ent of PRINTBUF
 * which covers needed ~110 extra bytes (and much more) */


/* Options */
enum {
	OPTBIT_mark = 0, // -m
	OPTBIT_nofork, // -n
	OPTBIT_outfile, // -O
	OPTBIT_loglevel, // -l
	OPTBIT_small, // -S
	USE_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,)	// -s
	USE_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,)	// -b
	USE_FEATURE_REMOTE_LOG(    OPTBIT_remote     ,)	// -R
	USE_FEATURE_REMOTE_LOG(    OPTBIT_localtoo   ,)	// -L
	USE_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,)	// -C

	OPT_mark        = 1 << OPTBIT_mark    ,
	OPT_nofork      = 1 << OPTBIT_nofork  ,
	OPT_outfile     = 1 << OPTBIT_outfile ,
	OPT_loglevel    = 1 << OPTBIT_loglevel,
	OPT_small       = 1 << OPTBIT_small   ,
	OPT_filesize    = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
	OPT_rotatecnt   = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
	OPT_remotelog   = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remote     )) + 0,
	OPT_locallog    = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_localtoo   )) + 0,
	OPT_circularlog = USE_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
};
#define OPTION_STR "m:nO:l:S" \
	USE_FEATURE_ROTATE_LOGFILE("s:" ) \
	USE_FEATURE_ROTATE_LOGFILE("b:" ) \
	USE_FEATURE_REMOTE_LOG(    "R:" ) \
	USE_FEATURE_REMOTE_LOG(    "L"  ) \
	USE_FEATURE_IPC_SYSLOG(    "C::")
#define OPTION_DECL *opt_m, *opt_l \
	USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
	USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
	USE_FEATURE_REMOTE_LOG(    ,*opt_R) \
	USE_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL)
#define OPTION_PARAM &opt_m, &logFilePath, &opt_l \
	USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
	USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
	USE_FEATURE_REMOTE_LOG(    ,&opt_R) \
	USE_FEATURE_IPC_SYSLOG(    ,&opt_C)


/* circular buffer variables/structures */
#if ENABLE_FEATURE_IPC_SYSLOG


#if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
#error Sorry, you must set the syslogd buffer size to at least 4KB.
#error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
#endif

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

/* our shared key */
#define KEY_ID ((long)0x414e4547) /* "GENA" */

// Semaphore operation structures
static struct shbuf_ds {
	int32_t size;   // size of data written
	int32_t head;   // start of message list
	int32_t tail;   // end of message list
	char data[1];   // data/messages
} *shbuf;               // shared memory pointer

static int shmid = -1;   // ipc shared memory id
static int s_semid = -1; // ipc semaphore id
static int shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024);	// default shm size

static void ipcsyslog_cleanup(void)
{
	if (shmid != -1) {
		shmdt(shbuf);
	}
	if (shmid != -1) {
		shmctl(shmid, IPC_RMID, NULL);
	}
	if (s_semid != -1) {
		semctl(s_semid, 0, IPC_RMID, 0);
	}
}

static void ipcsyslog_init(void)
{
	if (DEBUG)
		printf("shmget(%lx, %d,...)\n", KEY_ID, shm_size);

	shmid = shmget(KEY_ID, shm_size, IPC_CREAT | 1023);
	if (shmid == -1) {
		bb_perror_msg_and_die("shmget");
	}

	shbuf = shmat(shmid, NULL, 0);
	if (!shbuf) {
		bb_perror_msg_and_die("shmat");
	}

	shbuf->size = shm_size - offsetof(struct shbuf_ds, data);
	shbuf->head = shbuf->tail = 0;

	// we'll trust the OS to set initial semval to 0 (let's hope)
	s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
	if (s_semid == -1) {
		if (errno == EEXIST) {
			s_semid = semget(KEY_ID, 2, 0);
			if (s_semid != -1)
				return;
		}
		bb_perror_msg_and_die("semget");
	}
}

/* Write message to shared mem buffer */
static void log_to_shmem(const char *msg, int len)
{
	/* Why libc insists on these being rw? */
	static struct sembuf SMwup[1] = { {1, -1, IPC_NOWAIT} };
	static struct sembuf SMwdn[3] = { {0, 0}, {1, 0}, {1, +1} };

	int old_tail, new_tail;
	char *c;

	if (semop(s_semid, SMwdn, 3) == -1) {
		bb_perror_msg_and_die("SMwdn");
	}

	/* Circular Buffer Algorithm:
	 * --------------------------
	 * tail == position where to store next syslog message.
	 * head == position of next message to retrieve ("print").
	 * if head == tail, there is no "unprinted" messages left.
	 * head is typically advanced by separate "reader" program,
	 * but if there isn't one, we have to do it ourself.
	 * messages are NUL-separated.
	 */
	len++; /* length with NUL included */
 again:
	old_tail = shbuf->tail;
	new_tail = old_tail + len;
	if (new_tail < shbuf->size) {
		/* No need to move head if shbuf->head <= old_tail,
		 * else... */
		if (old_tail < shbuf->head && shbuf->head <= new_tail) {
			/* ...need to move head forward */
			c = memchr(shbuf->data + new_tail, '\0',
					   shbuf->size - new_tail);
			if (!c) /* no NUL ahead of us, wrap around */
				c = memchr(shbuf->data, '\0', old_tail);
			if (!c) { /* still nothing? point to this msg... */
				shbuf->head = old_tail;
			} else {
				/* convert pointer to offset + skip NUL */
				shbuf->head = c - shbuf->data + 1;
			}
		}
		/* store message, set new tail */
		memcpy(shbuf->data + old_tail, msg, len);
		shbuf->tail = new_tail;
	} else {
		/* we need to break up the message and wrap it around */
		/* k == available buffer space ahead of old tail */
		int k = shbuf->size - old_tail - 1;
		if (shbuf->head > old_tail) {
			/* we are going to overwrite head, need to
			 * move it out of the way */
			c = memchr(shbuf->data, '\0', old_tail);
			if (!c) { /* nothing? point to this msg... */
				shbuf->head = old_tail;
			} else { /* convert pointer to offset + skip NUL */
				shbuf->head = c - shbuf->data + 1;
			}
		}
		/* copy what fits to the end of buffer, and repeat */
		memcpy(shbuf->data + old_tail, msg, k);
		msg += k;
		len -= k;
		shbuf->tail = 0;
		goto again;
	}
	if (semop(s_semid, SMwup, 1) == -1) {
		bb_perror_msg_and_die("SMwup");
	}
	if (DEBUG)
		printf("head:%d tail:%d\n", shbuf->head, shbuf->tail);
}
#else
void ipcsyslog_cleanup(void);
void ipcsyslog_init(void);
void log_to_shmem(const char *msg);
#endif /* FEATURE_IPC_SYSLOG */


/* Print a message to the log file. */
static void log_locally(char *msg)
{
	static time_t last;
	struct flock fl;
	int len = strlen(msg);

#if ENABLE_FEATURE_IPC_SYSLOG
	if ((option_mask32 & OPT_circularlog) && shbuf) {
		log_to_shmem(msg, len);
		return;
	}
#endif
	if (logFD >= 0) {
		time_t cur;
		time(&cur);
		if (last != cur) {
			last = cur; /* reopen log file every second */
			close(logFD);
			goto reopen;
		}
	} else {
 reopen:
		logFD = device_open(logFilePath, O_WRONLY | O_CREAT
					| O_NOCTTY | O_APPEND | O_NONBLOCK);
		if (logFD < 0) {
			/* cannot open logfile? - print to /dev/console then */
			int fd = device_open(_PATH_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
			if (fd < 0)
				fd = 2; /* then stderr, dammit */
			full_write(fd, msg, len);
			if (fd != 2)
				close(fd);
			return;
		}
#if ENABLE_FEATURE_ROTATE_LOGFILE
		{
		struct stat statf;

		isRegular = (fstat(logFD, &statf) == 0 && (statf.st_mode & S_IFREG));
		/* bug (mostly harmless): can wrap around if file > 4gb */
		curFileSize = statf.st_size;
		}
#endif
	}

	fl.l_whence = SEEK_SET;
	fl.l_start = 0;
	fl.l_len = 1;
	fl.l_type = F_WRLCK;
	fcntl(logFD, F_SETLKW, &fl);

#if ENABLE_FEATURE_ROTATE_LOGFILE
	if (logFileSize && isRegular && curFileSize > logFileSize) {
		if (logFileRotate) { /* always 0..99 */
			int i = strlen(logFilePath) + 3 + 1;
			char oldFile[i];
			char newFile[i];
			i = logFileRotate - 1;
			/* rename: f.8 -> f.9; f.7 -> f.8; ... */
			while (1) {
				sprintf(newFile, "%s.%d", logFilePath, i);
				if (i == 0) break;
				sprintf(oldFile, "%s.%d", logFilePath, --i);
				rename(oldFile, newFile);
			}
			/* newFile == "f.0" now */
			rename(logFilePath, newFile);
			fl.l_type = F_UNLCK;
			fcntl(logFD, F_SETLKW, &fl);
			close(logFD);
			goto reopen;
		}
		ftruncate(logFD, 0);
	}
	curFileSize +=
#endif
	                full_write(logFD, msg, len);
	fl.l_type = F_UNLCK;
	fcntl(logFD, F_SETLKW, &fl);
}

static void parse_fac_prio_20(int pri, char *res20)
{
	CODE *c_pri, *c_fac;

	if (pri != 0) {
		c_fac = facilitynames;
		while (c_fac->c_name) {
			if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
				c_fac++; continue;
			}
			/* facility is found, look for prio */
			c_pri = prioritynames;
			while (c_pri->c_name) {
				if (c_pri->c_val != LOG_PRI(pri)) {
					c_pri++; continue;
				}
				snprintf(res20, 20, "%s.%s",
						c_fac->c_name, c_pri->c_name);
				return;
			}
			/* prio not found, bail out */
			break;
		}
		snprintf(res20, 20, "<%d>", pri);
	}
}

/* len parameter is used only for "is there a timestamp?" check.
 * NB: some callers cheat and supply 0 when they know
 * that there is no timestamp, short-cutting the test. */
static void timestamp_and_log(int pri, char *msg, int len)
{
	char *timestamp;

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

	/* Log message locally (to file or shared mem) */
	if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
		if (LOG_PRI(pri) < logLevel) {
			if (option_mask32 & OPT_small)
				sprintf(PRINTBUF, "%s %s\n", timestamp, msg);
			else {
				char res[20];
				parse_fac_prio_20(pri, res);
				sprintf(PRINTBUF, "%s %s %s %s\n", timestamp, localHostName, res, msg);
			}
			log_locally(PRINTBUF);
		}
	}
}

static void split_escape_and_log(char *tmpbuf, int len)
{
	char *p = tmpbuf;

	tmpbuf += len;
	while (p < tmpbuf) {
		char c;
		char *q = PARSEBUF;
		int pri = (LOG_USER | LOG_NOTICE);

		if (*p == '<') {
			/* Parse the magic priority number */
			pri = bb_strtou(p + 1, &p, 10);
			if (*p == '>') p++;
			if (pri & ~(LOG_FACMASK | LOG_PRIMASK)) {
				pri = (LOG_USER | LOG_NOTICE);
			}
		}

		while ((c = *p++)) {
			if (c == '\n')
				c = ' ';
			if (!(c & ~0x1f)) {
				*q++ = '^';
				c += '@'; /* ^@, ^A, ^B... */
			}
			*q++ = c;
		}
		*q = '\0';
		/* Now log it */
		timestamp_and_log(pri, PARSEBUF, q - PARSEBUF);
	}
}

static void quit_signal(int sig)
{
	timestamp_and_log(LOG_SYSLOG | LOG_INFO, "syslogd exiting", 0);
	puts("syslogd exiting");
	unlink(dev_log_name);
	if (ENABLE_FEATURE_IPC_SYSLOG)
		ipcsyslog_cleanup();
	exit(1);
}

static void do_mark(int sig)
{
	if (markInterval) {
		timestamp_and_log(LOG_SYSLOG | LOG_INFO, "-- MARK --", 0);
		alarm(markInterval);
	}
}

static void do_syslogd(void) ATTRIBUTE_NORETURN;
static void do_syslogd(void)
{
	struct sockaddr_un sunx;
	socklen_t addr_len;
	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, do_mark);
	alarm(markInterval);

	dev_log_name = xmalloc_realpath(_PATH_LOG);
	if (!dev_log_name)
		dev_log_name = _PATH_LOG;

	/* Unlink old /dev/log (or object it points to) */
	unlink(dev_log_name);

	memset(&sunx, 0, sizeof(sunx));
	sunx.sun_family = AF_UNIX;
	strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
	sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
	addr_len = sizeof(sunx.sun_family) + strlen(sunx.sun_path);
	xbind(sock_fd, (struct sockaddr *) &sunx, addr_len);

	if (chmod(dev_log_name, 0666) < 0) {
		bb_perror_msg_and_die("cannot set permission on %s", dev_log_name);
	}
	if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
		ipcsyslog_init();
	}

	timestamp_and_log(LOG_SYSLOG | LOG_INFO, "syslogd started: BusyBox v" BB_VER, 0);

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

		if (select(sock_fd + 1, &fds, NULL, NULL, NULL) < 0) {
			if (errno == EINTR) {
				/* alarm may have happened */
				continue;
			}
			bb_perror_msg_and_die("select");
		}

		if (FD_ISSET(sock_fd, &fds)) {
			int i;
			i = recv(sock_fd, RECVBUF, MAX_READ - 1, 0);
			if (i <= 0)
				bb_perror_msg_and_die("UNIX socket error");
			/* TODO: maybe suppress duplicates? */
#if ENABLE_FEATURE_REMOTE_LOG
			/* We are not modifying log messages in any way before send */
			/* Remote site cannot trust _us_ anyway and need to do validation again */
			if (remoteAddr) {
				if (-1 == remoteFD) {
					remoteFD = socket(remoteAddr->sa.sa_family, SOCK_DGRAM, 0);
				}
				if (-1 != remoteFD) {
					/* send message to remote logger, ignore possible error */
					sendto(remoteFD, RECVBUF, i, MSG_DONTWAIT,
						&remoteAddr->sa, remoteAddr->len);
				}
			}
#endif
			RECVBUF[i] = '\0';
			split_escape_and_log(RECVBUF, i);
		} /* FD_ISSET() */
	} /* for */
}

int syslogd_main(int argc, char **argv)
{
	char OPTION_DECL;
	char *p;

	/* do normal option parsing */
	opt_complementary = "=0"; /* no non-option params */
	getopt32(argc, argv, OPTION_STR, OPTION_PARAM);
	if (option_mask32 & OPT_mark) // -m
		markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
	//if (option_mask32 & OPT_nofork) // -n
	//if (option_mask32 & OPT_outfile) // -O
	if (option_mask32 & OPT_loglevel) // -l
		logLevel = xatou_range(opt_l, 1, 8);
	//if (option_mask32 & OPT_small) // -S
#if ENABLE_FEATURE_ROTATE_LOGFILE
	if (option_mask32 & OPT_filesize) // -s
		logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
	if (option_mask32 & OPT_rotatecnt) // -b
		logFileRotate = xatou_range(opt_b, 0, 99);
#endif
#if ENABLE_FEATURE_REMOTE_LOG
	if (option_mask32 & OPT_remotelog) { // -R
		remoteAddr = host2sockaddr(opt_R, 514);
	}
	//if (option_mask32 & OPT_locallog) // -L
#endif
#if ENABLE_FEATURE_IPC_SYSLOG
	if (opt_C) // -Cn
		shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
#endif

	/* If they have not specified remote logging, then log locally */
	if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_remotelog))
		option_mask32 |= OPT_locallog;

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

	if (!(option_mask32 & OPT_nofork)) {
#ifdef BB_NOMMU
		vfork_daemon_rexec(0, 1, argc, argv, "-n");
#else
		bb_daemonize();
#endif
	}
	umask(0);
	do_syslogd();
	/* return EXIT_SUCCESS; */
}
1	/* vi: set sw=4 ts=4: */
2	/*
3	* Mini syslogd implementation for busybox
4	*
5	* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
6	*
7	* Copyright (C) 2000 by Karl M. Hegbloom <karlheg@debian.org>
8	*
9	* "circular buffer" Copyright (C) 2001 by Gennady Feldman <gfeldman@gena01.com>
10	*
11	* Maintainer: Gennady Feldman <gfeldman@gena01.com> as of Mar 12, 2001
12	*
13	* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
14	*/
15
16	#include "busybox.h"
17	#include <paths.h>
18	#include <sys/un.h>
19
20	/* SYSLOG_NAMES defined to pull some extra junk from syslog.h */
21	#define SYSLOG_NAMES
22	#include <sys/syslog.h>
23	#include <sys/uio.h>
24
25	#define DEBUG 0
26
27	/* Path to the unix socket */
28	static char *dev_log_name;
29
30	/* Path for the file where all log messages are written */
31	static const char *logFilePath = "/var/log/messages";
32	static int logFD = -1;
33
34	/* interval between marks in seconds */
35	static int markInterval = 20 * 60;
36
37	/* level of messages to be locally logged */
38	static int logLevel = 8;
39
40	/* localhost's name */
41	static char localHostName[64];
42
43	#if ENABLE_FEATURE_ROTATE_LOGFILE
44	/* max size of message file before being rotated */
45	static unsigned logFileSize = 200 * 1024;
46	/* number of rotated message files */
47	static unsigned logFileRotate = 1;
48	static unsigned curFileSize;
49	static smallint isRegular;
50	#endif
51
52	#if ENABLE_FEATURE_REMOTE_LOG
53	#include <netinet/in.h>
54	/* udp socket for logging to remote host */
55	static int remoteFD = -1;
56	static len_and_sockaddr* remoteAddr;
57	#endif
58
59	/* We are using bb_common_bufsiz1 for buffering: */
60	enum { MAX_READ = (BUFSIZ/6) & ~0xf };
61	/* We recv into RECVBUF... (size: MAX_READ ~== BUFSIZ/6) */
62	#define RECVBUF bb_common_bufsiz1
63	/* ...then copy to PARSEBUF, escaping control chars */
64	/* (can grow x2 max ~== BUFSIZ/3) */
65	#define PARSEBUF (bb_common_bufsiz1 + MAX_READ)
66	/* ...then sprintf into PRINTBUF, adding timestamp (15 chars),
67	* host (64), fac.prio (20) to the message */
68	/* (growth by: 15 + 64 + 20 + delims = ~110) */
69	#define PRINTBUF (bb_common_bufsiz1 + 3*MAX_READ)
70	/* totals: BUFSIZ == BUFSIZ/6 + BUFSIZ/3 + (BUFSIZ/3+BUFSIZ/6)
71	* -- we have BUFSIZ/6 extra at the ent of PRINTBUF
72	* which covers needed ~110 extra bytes (and much more) */
73
74
75	/* Options */
76	enum {
77	OPTBIT_mark = 0, // -m
78	OPTBIT_nofork, // -n
79	OPTBIT_outfile, // -O
80	OPTBIT_loglevel, // -l
81	OPTBIT_small, // -S
82	USE_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize ,) // -s
83	USE_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt ,) // -b
84	USE_FEATURE_REMOTE_LOG( OPTBIT_remote ,) // -R
85	USE_FEATURE_REMOTE_LOG( OPTBIT_localtoo ,) // -L
86	USE_FEATURE_IPC_SYSLOG( OPTBIT_circularlog,) // -C
87
88	OPT_mark = 1 << OPTBIT_mark ,
89	OPT_nofork = 1 << OPTBIT_nofork ,
90	OPT_outfile = 1 << OPTBIT_outfile ,
91	OPT_loglevel = 1 << OPTBIT_loglevel,
92	OPT_small = 1 << OPTBIT_small ,
93	OPT_filesize = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize )) + 0,
94	OPT_rotatecnt = USE_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt )) + 0,
95	OPT_remotelog = USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_remote )) + 0,
96	OPT_locallog = USE_FEATURE_REMOTE_LOG( (1 << OPTBIT_localtoo )) + 0,
97	OPT_circularlog = USE_FEATURE_IPC_SYSLOG( (1 << OPTBIT_circularlog)) + 0,
98	};
99	#define OPTION_STR "m:nO:l:S" \
100	USE_FEATURE_ROTATE_LOGFILE("s:" ) \
101	USE_FEATURE_ROTATE_LOGFILE("b:" ) \
102	USE_FEATURE_REMOTE_LOG( "R:" ) \
103	USE_FEATURE_REMOTE_LOG( "L" ) \
104	USE_FEATURE_IPC_SYSLOG( "C::")
105	#define OPTION_DECL opt_m, opt_l \
106	USE_FEATURE_ROTATE_LOGFILE(,*opt_s) \
107	USE_FEATURE_ROTATE_LOGFILE(,*opt_b) \
108	USE_FEATURE_REMOTE_LOG( ,*opt_R) \
109	USE_FEATURE_IPC_SYSLOG( ,*opt_C = NULL)
110	#define OPTION_PARAM &opt_m, &logFilePath, &opt_l \
111	USE_FEATURE_ROTATE_LOGFILE(,&opt_s) \
112	USE_FEATURE_ROTATE_LOGFILE(,&opt_b) \
113	USE_FEATURE_REMOTE_LOG( ,&opt_R) \
114	USE_FEATURE_IPC_SYSLOG( ,&opt_C)
115
116
117	/* circular buffer variables/structures */
118	#if ENABLE_FEATURE_IPC_SYSLOG
119
120
121	#if CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE < 4
122	#error Sorry, you must set the syslogd buffer size to at least 4KB.
123	#error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
124	#endif
125
126	#include <sys/ipc.h>
127	#include <sys/sem.h>
128	#include <sys/shm.h>
129
130	/* our shared key */
131	#define KEY_ID ((long)0x414e4547) /* "GENA" */
132
133	// Semaphore operation structures
134	static struct shbuf_ds {
135	int32_t size; // size of data written
136	int32_t head; // start of message list
137	int32_t tail; // end of message list
138	char data[1]; // data/messages
139	} *shbuf; // shared memory pointer
140
141	static int shmid = -1; // ipc shared memory id
142	static int s_semid = -1; // ipc semaphore id
143	static int shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024); // default shm size
144
145	static void ipcsyslog_cleanup(void)
146	{
147	if (shmid != -1) {
148	shmdt(shbuf);
149	}
150	if (shmid != -1) {
151	shmctl(shmid, IPC_RMID, NULL);
152	}
153	if (s_semid != -1) {
154	semctl(s_semid, 0, IPC_RMID, 0);
155	}
156	}
157
158	static void ipcsyslog_init(void)
159	{
160	if (DEBUG)
161	printf("shmget(%lx, %d,...)\n", KEY_ID, shm_size);
162
163	shmid = shmget(KEY_ID, shm_size, IPC_CREAT \| 1023);
164	if (shmid == -1) {
165	bb_perror_msg_and_die("shmget");
166	}
167
168	shbuf = shmat(shmid, NULL, 0);
169	if (!shbuf) {
170	bb_perror_msg_and_die("shmat");
171	}
172
173	shbuf->size = shm_size - offsetof(struct shbuf_ds, data);
174	shbuf->head = shbuf->tail = 0;
175
176	// we'll trust the OS to set initial semval to 0 (let's hope)
177	s_semid = semget(KEY_ID, 2, IPC_CREAT \| IPC_EXCL \| 1023);
178	if (s_semid == -1) {
179	if (errno == EEXIST) {
180	s_semid = semget(KEY_ID, 2, 0);
181	if (s_semid != -1)
182	return;
183	}
184	bb_perror_msg_and_die("semget");
185	}
186	}
187
188	/* Write message to shared mem buffer */
189	static void log_to_shmem(const char *msg, int len)
190	{
191	/* Why libc insists on these being rw? */
192	static struct sembuf SMwup[1] = { {1, -1, IPC_NOWAIT} };
193	static struct sembuf SMwdn[3] = { {0, 0}, {1, 0}, {1, +1} };
194
195	int old_tail, new_tail;
196	char *c;
197
198	if (semop(s_semid, SMwdn, 3) == -1) {
199	bb_perror_msg_and_die("SMwdn");
200	}
201
202	/* Circular Buffer Algorithm:
203	* --------------------------
204	* tail == position where to store next syslog message.
205	* head == position of next message to retrieve ("print").
206	* if head == tail, there is no "unprinted" messages left.
207	* head is typically advanced by separate "reader" program,
208	* but if there isn't one, we have to do it ourself.
209	* messages are NUL-separated.
210	*/
211	len++; /* length with NUL included */
212	again:
213	old_tail = shbuf->tail;
214	new_tail = old_tail + len;
215	if (new_tail < shbuf->size) {
216	/* No need to move head if shbuf->head <= old_tail,
217	* else... */
218	if (old_tail < shbuf->head && shbuf->head <= new_tail) {
219	/* ...need to move head forward */
220	c = memchr(shbuf->data + new_tail, '\0',
221	shbuf->size - new_tail);
222	if (!c) /* no NUL ahead of us, wrap around */
223	c = memchr(shbuf->data, '\0', old_tail);
224	if (!c) { /* still nothing? point to this msg... */
225	shbuf->head = old_tail;
226	} else {
227	/* convert pointer to offset + skip NUL */
228	shbuf->head = c - shbuf->data + 1;
229	}
230	}
231	/* store message, set new tail */
232	memcpy(shbuf->data + old_tail, msg, len);
233	shbuf->tail = new_tail;
234	} else {
235	/* we need to break up the message and wrap it around */
236	/* k == available buffer space ahead of old tail */
237	int k = shbuf->size - old_tail - 1;
238	if (shbuf->head > old_tail) {
239	/* we are going to overwrite head, need to
240	* move it out of the way */
241	c = memchr(shbuf->data, '\0', old_tail);
242	if (!c) { /* nothing? point to this msg... */
243	shbuf->head = old_tail;
244	} else { /* convert pointer to offset + skip NUL */
245	shbuf->head = c - shbuf->data + 1;
246	}
247	}
248	/* copy what fits to the end of buffer, and repeat */
249	memcpy(shbuf->data + old_tail, msg, k);
250	msg += k;
251	len -= k;
252	shbuf->tail = 0;
253	goto again;
254	}
255	if (semop(s_semid, SMwup, 1) == -1) {
256	bb_perror_msg_and_die("SMwup");
257	}
258	if (DEBUG)
259	printf("head:%d tail:%d\n", shbuf->head, shbuf->tail);
260	}
261	#else
262	void ipcsyslog_cleanup(void);
263	void ipcsyslog_init(void);
264	void log_to_shmem(const char *msg);
265	#endif /* FEATURE_IPC_SYSLOG */
266
267
268	/* Print a message to the log file. */
269	static void log_locally(char *msg)
270	{
271	static time_t last;
272	struct flock fl;
273	int len = strlen(msg);
274
275	#if ENABLE_FEATURE_IPC_SYSLOG
276	if ((option_mask32 & OPT_circularlog) && shbuf) {
277	log_to_shmem(msg, len);
278	return;
279	}
280	#endif
281	if (logFD >= 0) {
282	time_t cur;
283	time(&cur);
284	if (last != cur) {
285	last = cur; /* reopen log file every second */
286	close(logFD);
287	goto reopen;
288	}
289	} else {
290	reopen:
291	logFD = device_open(logFilePath, O_WRONLY \| O_CREAT
292	\| O_NOCTTY \| O_APPEND \| O_NONBLOCK);
293	if (logFD < 0) {
294	/* cannot open logfile? - print to /dev/console then */
295	int fd = device_open(_PATH_CONSOLE, O_WRONLY \| O_NOCTTY \| O_NONBLOCK);
296	if (fd < 0)
297	fd = 2; /* then stderr, dammit */
298	full_write(fd, msg, len);
299	if (fd != 2)
300	close(fd);
301	return;
302	}
303	#if ENABLE_FEATURE_ROTATE_LOGFILE
304	{
305	struct stat statf;
306
307	isRegular = (fstat(logFD, &statf) == 0 && (statf.st_mode & S_IFREG));
308	/* bug (mostly harmless): can wrap around if file > 4gb */
309	curFileSize = statf.st_size;
310	}
311	#endif
312	}
313
314	fl.l_whence = SEEK_SET;
315	fl.l_start = 0;
316	fl.l_len = 1;
317	fl.l_type = F_WRLCK;
318	fcntl(logFD, F_SETLKW, &fl);
319
320	#if ENABLE_FEATURE_ROTATE_LOGFILE
321	if (logFileSize && isRegular && curFileSize > logFileSize) {
322	if (logFileRotate) { /* always 0..99 */
323	int i = strlen(logFilePath) + 3 + 1;
324	char oldFile[i];
325	char newFile[i];
326	i = logFileRotate - 1;
327	/* rename: f.8 -> f.9; f.7 -> f.8; ... */
328	while (1) {
329	sprintf(newFile, "%s.%d", logFilePath, i);
330	if (i == 0) break;
331	sprintf(oldFile, "%s.%d", logFilePath, --i);
332	rename(oldFile, newFile);
333	}
334	/* newFile == "f.0" now */
335	rename(logFilePath, newFile);
336	fl.l_type = F_UNLCK;
337	fcntl(logFD, F_SETLKW, &fl);
338	close(logFD);
339	goto reopen;
340	}
341	ftruncate(logFD, 0);
342	}
343	curFileSize +=
344	#endif
345	full_write(logFD, msg, len);
346	fl.l_type = F_UNLCK;
347	fcntl(logFD, F_SETLKW, &fl);
348	}
349
350	static void parse_fac_prio_20(int pri, char *res20)
351	{
352	CODE c_pri, c_fac;
353
354	if (pri != 0) {
355	c_fac = facilitynames;
356	while (c_fac->c_name) {
357	if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
358	c_fac++; continue;
359	}
360	/* facility is found, look for prio */
361	c_pri = prioritynames;
362	while (c_pri->c_name) {
363	if (c_pri->c_val != LOG_PRI(pri)) {
364	c_pri++; continue;
365	}
366	snprintf(res20, 20, "%s.%s",
367	c_fac->c_name, c_pri->c_name);
368	return;
369	}
370	/* prio not found, bail out */
371	break;
372	}
373	snprintf(res20, 20, "<%d>", pri);
374	}
375	}
376
377	/* len parameter is used only for "is there a timestamp?" check.
378	* NB: some callers cheat and supply 0 when they know
379	* that there is no timestamp, short-cutting the test. */
380	static void timestamp_and_log(int pri, char *msg, int len)
381	{
382	char *timestamp;
383
384	if (len < 16 \|\| msg[3] != ' ' \|\| msg[6] != ' '
385	\|\| msg[9] != ':' \|\| msg[12] != ':' \|\| msg[15] != ' '
386	) {
387	time_t now;
388	time(&now);
389	timestamp = ctime(&now) + 4;
390	} else {
391	timestamp = msg;
392	msg += 16;
393	}
394	timestamp[15] = '\0';
395
396	/* Log message locally (to file or shared mem) */
397	if (!ENABLE_FEATURE_REMOTE_LOG \|\| (option_mask32 & OPT_locallog)) {
398	if (LOG_PRI(pri) < logLevel) {
399	if (option_mask32 & OPT_small)
400	sprintf(PRINTBUF, "%s %s\n", timestamp, msg);
401	else {
402	char res[20];
403	parse_fac_prio_20(pri, res);
404	sprintf(PRINTBUF, "%s %s %s %s\n", timestamp, localHostName, res, msg);
405	}
406	log_locally(PRINTBUF);
407	}
408	}
409	}
410
411	static void split_escape_and_log(char *tmpbuf, int len)
412	{
413	char *p = tmpbuf;
414
415	tmpbuf += len;
416	while (p < tmpbuf) {
417	char c;
418	char *q = PARSEBUF;
419	int pri = (LOG_USER \| LOG_NOTICE);
420
421	if (*p == '<') {
422	/* Parse the magic priority number */
423	pri = bb_strtou(p + 1, &p, 10);
424	if (*p == '>') p++;
425	if (pri & ~(LOG_FACMASK \| LOG_PRIMASK)) {
426	pri = (LOG_USER \| LOG_NOTICE);
427	}
428	}
429
430	while ((c = *p++)) {
431	if (c == '\n')
432	c = ' ';
433	if (!(c & ~0x1f)) {
434	*q++ = '^';
435	c += '@'; /* ^@, ^A, ^B... */
436	}
437	*q++ = c;
438	}
439	*q = '\0';
440	/* Now log it */
441	timestamp_and_log(pri, PARSEBUF, q - PARSEBUF);
442	}
443	}
444
445	static void quit_signal(int sig)
446	{
447	timestamp_and_log(LOG_SYSLOG \| LOG_INFO, "syslogd exiting", 0);
448	puts("syslogd exiting");
449	unlink(dev_log_name);
450	if (ENABLE_FEATURE_IPC_SYSLOG)
451	ipcsyslog_cleanup();
452	exit(1);
453	}
454
455	static void do_mark(int sig)
456	{
457	if (markInterval) {
458	timestamp_and_log(LOG_SYSLOG \| LOG_INFO, "-- MARK --", 0);
459	alarm(markInterval);
460	}
461	}
462
463	static void do_syslogd(void) ATTRIBUTE_NORETURN;
464	static void do_syslogd(void)
465	{
466	struct sockaddr_un sunx;
467	socklen_t addr_len;
468	int sock_fd;
469	fd_set fds;
470
471	/* Set up signal handlers */
472	signal(SIGINT, quit_signal);
473	signal(SIGTERM, quit_signal);
474	signal(SIGQUIT, quit_signal);
475	signal(SIGHUP, SIG_IGN);
476	signal(SIGCHLD, SIG_IGN);
477	#ifdef SIGCLD
478	signal(SIGCLD, SIG_IGN);
479	#endif
480	signal(SIGALRM, do_mark);
481	alarm(markInterval);
482
483	dev_log_name = xmalloc_realpath(_PATH_LOG);
484	if (!dev_log_name)
485	dev_log_name = _PATH_LOG;
486
487	/* Unlink old /dev/log (or object it points to) */
488	unlink(dev_log_name);
489
490	memset(&sunx, 0, sizeof(sunx));
491	sunx.sun_family = AF_UNIX;
492	strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
493	sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
494	addr_len = sizeof(sunx.sun_family) + strlen(sunx.sun_path);
495	xbind(sock_fd, (struct sockaddr *) &sunx, addr_len);
496
497	if (chmod(dev_log_name, 0666) < 0) {
498	bb_perror_msg_and_die("cannot set permission on %s", dev_log_name);
499	}
500	if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
501	ipcsyslog_init();
502	}
503
504	timestamp_and_log(LOG_SYSLOG \| LOG_INFO, "syslogd started: BusyBox v" BB_VER, 0);
505
506	for (;;) {
507	FD_ZERO(&fds);
508	FD_SET(sock_fd, &fds);
509
510	if (select(sock_fd + 1, &fds, NULL, NULL, NULL) < 0) {
511	if (errno == EINTR) {
512	/* alarm may have happened */
513	continue;
514	}
515	bb_perror_msg_and_die("select");
516	}
517
518	if (FD_ISSET(sock_fd, &fds)) {
519	int i;
520	i = recv(sock_fd, RECVBUF, MAX_READ - 1, 0);
521	if (i <= 0)
522	bb_perror_msg_and_die("UNIX socket error");
523	/* TODO: maybe suppress duplicates? */
524	#if ENABLE_FEATURE_REMOTE_LOG
525	/* We are not modifying log messages in any way before send */
526	/* Remote site cannot trust _us_ anyway and need to do validation again */
527	if (remoteAddr) {
528	if (-1 == remoteFD) {
529	remoteFD = socket(remoteAddr->sa.sa_family, SOCK_DGRAM, 0);
530	}
531	if (-1 != remoteFD) {
532	/* send message to remote logger, ignore possible error */
533	sendto(remoteFD, RECVBUF, i, MSG_DONTWAIT,
534	&remoteAddr->sa, remoteAddr->len);
535	}
536	}
537	#endif
538	RECVBUF[i] = '\0';
539	split_escape_and_log(RECVBUF, i);
540	} /* FD_ISSET() */
541	} /* for */
542	}
543
544	int syslogd_main(int argc, char **argv)
545	{
546	char OPTION_DECL;
547	char *p;
548
549	/* do normal option parsing */
550	opt_complementary = "=0"; /* no non-option params */
551	getopt32(argc, argv, OPTION_STR, OPTION_PARAM);
552	if (option_mask32 & OPT_mark) // -m
553	markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
554	//if (option_mask32 & OPT_nofork) // -n
555	//if (option_mask32 & OPT_outfile) // -O
556	if (option_mask32 & OPT_loglevel) // -l
557	logLevel = xatou_range(opt_l, 1, 8);
558	//if (option_mask32 & OPT_small) // -S
559	#if ENABLE_FEATURE_ROTATE_LOGFILE
560	if (option_mask32 & OPT_filesize) // -s
561	logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
562	if (option_mask32 & OPT_rotatecnt) // -b
563	logFileRotate = xatou_range(opt_b, 0, 99);
564	#endif
565	#if ENABLE_FEATURE_REMOTE_LOG
566	if (option_mask32 & OPT_remotelog) { // -R
567	remoteAddr = host2sockaddr(opt_R, 514);
568	}
569	//if (option_mask32 & OPT_locallog) // -L
570	#endif
571	#if ENABLE_FEATURE_IPC_SYSLOG
572	if (opt_C) // -Cn
573	shm_size = xatoul_range(opt_C, 4, INT_MAX/1024) * 1024;
574	#endif
575
576	/* If they have not specified remote logging, then log locally */
577	if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_remotelog))
578	option_mask32 \|= OPT_locallog;
579
580	/* Store away localhost's name before the fork */
581	gethostname(localHostName, sizeof(localHostName));
582	p = strchr(localHostName, '.');
583	if (p) {
584	*p = '\0';
585	}
586
587	if (!(option_mask32 & OPT_nofork)) {
588	#ifdef BB_NOMMU
589	vfork_daemon_rexec(0, 1, argc, argv, "-n");
590	#else
591	bb_daemonize();
592	#endif
593	}
594	umask(0);
595	do_syslogd();
596	/* return EXIT_SUCCESS; */
597	}