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busybox/sysklogd/syslogd.c

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/* 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 struct sockaddr_in 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, "System log daemon exiting", 0);
puts("System log daemon 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 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, 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);
addrLength = sizeof(sunx.sun_family) + strlen(sunx.sun_path);
xbind(sock_fd, (struct sockaddr *) &sunx, addrLength);
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 (option_mask32 & OPT_remotelog) {
if (-1 == remoteFD) {
remoteFD = socket(AF_INET, SOCK_DGRAM, 0);
}
if (-1 != remoteFD) {
/* send message to remote logger, ignore possible error */
sendto(remoteFD, RECVBUF, i, MSG_DONTWAIT,
(struct sockaddr *) &remoteAddr,
sizeof(remoteAddr));
}
}
#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
int port = 514;
p = strchr(opt_R, ':');
if (p) {
*p++ = '\0';
port = xatou16(p);
}
/* FIXME: looks ip4-specific. need to do better */
bb_lookup_host(&remoteAddr, opt_R);
remoteAddr.sin_port = bb_lookup_port(port, "udp", port);
}
//if (option_mask32 & OPT_locallog) // -L
#endif
#if ENABLE_FEATURE_IPC_SYSLOG
if ((option_mask32 & OPT_circularlog) && opt_C) // -C
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
xdaemon(0, 1);
#endif
}
umask(0);
do_syslogd();
/* return EXIT_SUCCESS; */
}
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