dd: free allocated memory if CLEANUP enabled
[oweals/busybox.git] / sysklogd / syslogd.c
index 6ecbd16f018c17498fbda581f365da5ae2d4de2f..24cab3b6c68c66954d556f9dc9d5c613dc18326a 100644 (file)
  *
  * 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.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
+/*
+ * Done in syslogd_and_logger.c:
 #include "libbb.h"
-#include <paths.h>
-#include <sys/un.h>
-
-/* SYSLOG_NAMES defined to pull prioritynames[] and facilitynames[]
- * from syslog.h. Grrrr - glibc puts those in _rwdata_! :( */
 #define SYSLOG_NAMES
-#define SYSLOG_NAMES_CONST /* uclibc is saner :) */
-#include <sys/syslog.h>
+#define SYSLOG_NAMES_CONST
+#include <syslog.h>
+*/
+
+#include <sys/un.h>
 #include <sys/uio.h>
 
 #if ENABLE_FEATURE_REMOTE_LOG
  * (semaphores are down but do_mark routine tries to down them again) */
 #undef SYSLOGD_MARK
 
-enum { MAX_READ = 256 };
+/* Write locking does not seem to be useful either */
+#undef SYSLOGD_WRLOCK
+
+enum {
+       MAX_READ = CONFIG_FEATURE_SYSLOGD_READ_BUFFER_SIZE,
+       DNS_WAIT_SEC = 2 * 60,
+};
 
 /* Semaphore operation structures */
 struct shbuf_ds {
@@ -51,6 +57,15 @@ struct shbuf_ds {
        char data[1];   /* data/messages */
 };
 
+#if ENABLE_FEATURE_REMOTE_LOG
+typedef struct {
+       int remoteFD;
+       unsigned last_dns_resolve;
+       len_and_sockaddr *remoteAddr;
+       const char *remoteHostname;
+} remoteHost_t;
+#endif
+
 /* Allows us to have smaller initializer. Ugly. */
 #define GLOBALS \
        const char *logFilePath;                \
@@ -59,7 +74,7 @@ struct shbuf_ds {
        /*int markInterval;*/                   \
        /* level of messages to be logged */    \
        int logLevel;                           \
-USE_FEATURE_ROTATE_LOGFILE( \
+IF_FEATURE_ROTATE_LOGFILE( \
        /* max size of file before rotation */  \
        unsigned logFileSize;                   \
        /* number of rotated message files */   \
@@ -67,12 +82,7 @@ USE_FEATURE_ROTATE_LOGFILE( \
        unsigned curFileSize;                   \
        smallint isRegular;                     \
 ) \
-USE_FEATURE_REMOTE_LOG( \
-       /* udp socket for remote logging */     \
-       int remoteFD;                           \
-       len_and_sockaddr* remoteAddr;           \
-) \
-USE_FEATURE_IPC_SYSLOG( \
+IF_FEATURE_IPC_SYSLOG( \
        int shmid; /* ipc shared memory id */   \
        int s_semid; /* ipc semaphore id */     \
        int shm_size;                           \
@@ -86,15 +96,19 @@ struct init_globals {
 
 struct globals {
        GLOBALS
+
+#if ENABLE_FEATURE_REMOTE_LOG
+       llist_t *remoteHosts;
+#endif
 #if ENABLE_FEATURE_IPC_SYSLOG
        struct shbuf_ds *shbuf;
 #endif
        time_t last_log_time;
-       /* localhost's name */
-       char localHostName[64];
+       /* localhost's name. We print only first 64 chars */
+       char *hostname;
 
        /* We recv into recvbuf... */
-       char recvbuf[MAX_READ];
+       char recvbuf[MAX_READ * (1 + ENABLE_FEATURE_SYSLOGD_DUP)];
        /* ...then copy to parsebuf, escaping control chars */
        /* (can grow x2 max) */
        char parsebuf[MAX_READ*2];
@@ -115,9 +129,6 @@ static const struct init_globals init_data = {
        .logFileSize = 200 * 1024,
        .logFileRotate = 1,
 #endif
-#if ENABLE_FEATURE_REMOTE_LOG
-       .remoteFD = -1,
-#endif
 #if ENABLE_FEATURE_IPC_SYSLOG
        .shmid = -1,
        .s_semid = -1,
@@ -128,6 +139,9 @@ static const struct init_globals init_data = {
 };
 
 #define G (*ptr_to_globals)
+#define INIT_G() do { \
+       SET_PTR_TO_GLOBALS(memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data))); \
+} while (0)
 
 
 /* Options */
@@ -137,39 +151,41 @@ enum {
        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
+       IF_FEATURE_ROTATE_LOGFILE(OPTBIT_filesize   ,)  // -s
+       IF_FEATURE_ROTATE_LOGFILE(OPTBIT_rotatecnt  ,)  // -b
+       IF_FEATURE_REMOTE_LOG(    OPTBIT_remotelog  ,)  // -R
+       IF_FEATURE_REMOTE_LOG(    OPTBIT_locallog   ,)  // -L
+       IF_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,)  // -C
+       IF_FEATURE_SYSLOGD_DUP(   OPTBIT_dup        ,)  // -D
 
        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,
+       OPT_filesize    = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_filesize   )) + 0,
+       OPT_rotatecnt   = IF_FEATURE_ROTATE_LOGFILE((1 << OPTBIT_rotatecnt  )) + 0,
+       OPT_remotelog   = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_remotelog  )) + 0,
+       OPT_locallog    = IF_FEATURE_REMOTE_LOG(    (1 << OPTBIT_locallog   )) + 0,
+       OPT_circularlog = IF_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
+       OPT_dup         = IF_FEATURE_SYSLOGD_DUP(   (1 << OPTBIT_dup        )) + 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::")
+       IF_FEATURE_ROTATE_LOGFILE("s:" ) \
+       IF_FEATURE_ROTATE_LOGFILE("b:" ) \
+       IF_FEATURE_REMOTE_LOG(    "R:" ) \
+       IF_FEATURE_REMOTE_LOG(    "L"  ) \
+       IF_FEATURE_IPC_SYSLOG(    "C::") \
+       IF_FEATURE_SYSLOGD_DUP(   "D"  )
 #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)
+       IF_FEATURE_ROTATE_LOGFILE(,*opt_s) \
+       IF_FEATURE_ROTATE_LOGFILE(,*opt_b) \
+       IF_FEATURE_IPC_SYSLOG(    ,*opt_C = NULL)
 #define OPTION_PARAM &opt_m, &G.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)
+       IF_FEATURE_ROTATE_LOGFILE(,&opt_s) \
+       IF_FEATURE_ROTATE_LOGFILE(,&opt_b) \
+       IF_FEATURE_REMOTE_LOG(    ,&remoteAddrList) \
+       IF_FEATURE_IPC_SYSLOG(    ,&opt_C)
 
 
 /* circular buffer variables/structures */
@@ -180,8 +196,8 @@ enum {
 #error Please check CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE
 #endif
 
-/* our shared key */
-#define KEY_ID ((long)0x414e4547) /* "GENA" */
+/* our shared key (syslogd.c and logread.c must be in sync) */
+enum { KEY_ID = 0x414e4547 }; /* "GENA" */
 
 static void ipcsyslog_cleanup(void)
 {
@@ -199,15 +215,15 @@ static void ipcsyslog_cleanup(void)
 static void ipcsyslog_init(void)
 {
        if (DEBUG)
-               printf("shmget(%lx, %d,...)\n", KEY_ID, G.shm_size);
+               printf("shmget(%x, %d,...)\n", (int)KEY_ID, G.shm_size);
 
-       G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 1023);
+       G.shmid = shmget(KEY_ID, G.shm_size, IPC_CREAT | 0644);
        if (G.shmid == -1) {
                bb_perror_msg_and_die("shmget");
        }
 
        G.shbuf = shmat(G.shmid, NULL, 0);
-       if (!G.shbuf) {
+       if (G.shbuf == (void*) -1L) { /* shmat has bizarre error return */
                bb_perror_msg_and_die("shmat");
        }
 
@@ -274,9 +290,11 @@ void log_to_shmem(const char *msg);
 
 
 /* Print a message to the log file. */
-static void log_locally(char *msg)
+static void log_locally(time_t now, char *msg)
 {
+#ifdef SYSLOGD_WRLOCK
        struct flock fl;
+#endif
        int len = strlen(msg);
 
 #if ENABLE_FEATURE_IPC_SYSLOG
@@ -286,20 +304,26 @@ static void log_locally(char *msg)
        }
 #endif
        if (G.logFD >= 0) {
-               time_t cur;
-               time(&cur);
-               if (G.last_log_time != cur) {
-                       G.last_log_time = cur; /* reopen log file every second */
+               /* Reopen log file every second. This allows admin
+                * to delete the file and not worry about restarting us.
+                * This costs almost nothing since it happens
+                * _at most_ once a second.
+                */
+               if (!now)
+                       now = time(NULL);
+               if (G.last_log_time != now) {
+                       G.last_log_time = now;
                        close(G.logFD);
                        goto reopen;
                }
        } else {
  reopen:
-               G.logFD = device_open(G.logFilePath, O_WRONLY | O_CREAT
-                                       | O_NOCTTY | O_APPEND | O_NONBLOCK);
+               G.logFD = open(G.logFilePath, O_WRONLY | O_CREAT
+                                       | O_NOCTTY | O_APPEND | O_NONBLOCK,
+                                       0666);
                if (G.logFD < 0) {
                        /* cannot open logfile? - print to /dev/console then */
-                       int fd = device_open(_PATH_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
+                       int fd = device_open(DEV_CONSOLE, O_WRONLY | O_NOCTTY | O_NONBLOCK);
                        if (fd < 0)
                                fd = 2; /* then stderr, dammit */
                        full_write(fd, msg, len);
@@ -317,11 +341,13 @@ static void log_locally(char *msg)
 #endif
        }
 
+#ifdef SYSLOGD_WRLOCK
        fl.l_whence = SEEK_SET;
        fl.l_start = 0;
        fl.l_len = 1;
        fl.l_type = F_WRLCK;
        fcntl(G.logFD, F_SETLKW, &fl);
+#endif
 
 #if ENABLE_FEATURE_ROTATE_LOGFILE
        if (G.logFileSize && G.isRegular && G.curFileSize > G.logFileSize) {
@@ -335,12 +361,15 @@ static void log_locally(char *msg)
                                sprintf(newFile, "%s.%d", G.logFilePath, i);
                                if (i == 0) break;
                                sprintf(oldFile, "%s.%d", G.logFilePath, --i);
+                               /* ignore errors - file might be missing */
                                rename(oldFile, newFile);
                        }
                        /* newFile == "f.0" now */
                        rename(G.logFilePath, newFile);
+#ifdef SYSLOGD_WRLOCK
                        fl.l_type = F_UNLCK;
                        fcntl(G.logFD, F_SETLKW, &fl);
+#endif
                        close(G.logFD);
                        goto reopen;
                }
@@ -348,9 +377,11 @@ static void log_locally(char *msg)
        }
        G.curFileSize +=
 #endif
-                       full_write(G.logFD, msg, len);
+                       full_write(G.logFD, msg, len);
+#ifdef SYSLOGD_WRLOCK
        fl.l_type = F_UNLCK;
        fcntl(G.logFD, F_SETLKW, &fl);
+#endif
 }
 
 static void parse_fac_prio_20(int pri, char *res20)
@@ -361,13 +392,15 @@ static void parse_fac_prio_20(int pri, char *res20)
                c_fac = facilitynames;
                while (c_fac->c_name) {
                        if (c_fac->c_val != (LOG_FAC(pri) << 3)) {
-                               c_fac++; continue;
+                               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;
+                                       c_pri++;
+                                       continue;
                                }
                                snprintf(res20, 20, "%s.%s",
                                                c_fac->c_name, c_pri->c_name);
@@ -381,39 +414,50 @@ static void parse_fac_prio_20(int pri, char *res20)
 }
 
 /* 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. */
+ * NB: some callers cheat and supply len==0 when they know
+ * that there is no timestamp, short-circuiting the test. */
 static void timestamp_and_log(int pri, char *msg, int len)
 {
        char *timestamp;
+       time_t now;
 
+       /* Jan 18 00:11:22 msg... */
+       /* 01234567890123456 */
        if (len < 16 || msg[3] != ' ' || msg[6] != ' '
         || msg[9] != ':' || msg[12] != ':' || msg[15] != ' '
        ) {
-               time_t now;
                time(&now);
-               timestamp = ctime(&now) + 4;
+               timestamp = ctime(&now) + 4; /* skip day of week */
        } else {
+               now = 0;
                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) < G.logLevel) {
-                       if (option_mask32 & OPT_small)
-                               sprintf(G.printbuf, "%s %s\n", timestamp, msg);
-                       else {
-                               char res[20];
-                               parse_fac_prio_20(pri, res);
-                               sprintf(G.printbuf, "%s %s %s %s\n", timestamp, G.localHostName, res, msg);
-                       }
-                       log_locally(G.printbuf);
-               }
+       if (option_mask32 & OPT_small)
+               sprintf(G.printbuf, "%s %s\n", timestamp, msg);
+       else {
+               char res[20];
+               parse_fac_prio_20(pri, res);
+               sprintf(G.printbuf, "%s %.64s %s %s\n", timestamp, G.hostname, res, msg);
        }
+
+       /* Log message locally (to file or shared mem) */
+       log_locally(now, G.printbuf);
+}
+
+static void timestamp_and_log_internal(const char *msg)
+{
+       /* -L, or no -R */
+       if (ENABLE_FEATURE_REMOTE_LOG && !(option_mask32 & OPT_locallog))
+               return;
+       timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)msg, 0);
 }
 
+/* tmpbuf[len] is a NUL byte (set by caller), but there can be other,
+ * embedded NULs. Split messages on each of these NULs, parse prio,
+ * escape control chars and log each locally. */
 static void split_escape_and_log(char *tmpbuf, int len)
 {
        char *p = tmpbuf;
@@ -427,10 +471,10 @@ static void split_escape_and_log(char *tmpbuf, int len)
                if (*p == '<') {
                        /* Parse the magic priority number */
                        pri = bb_strtou(p + 1, &p, 10);
-                       if (*p == '>') p++;
-                       if (pri & ~(LOG_FACMASK | LOG_PRIMASK)) {
+                       if (*p == '>')
+                               p++;
+                       if (pri & ~(LOG_FACMASK | LOG_PRIMASK))
                                pri = (LOG_USER | LOG_NOTICE);
-                       }
                }
 
                while ((c = *p++)) {
@@ -443,179 +487,263 @@ static void split_escape_and_log(char *tmpbuf, int len)
                        *q++ = c;
                }
                *q = '\0';
+
                /* Now log it */
-               timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
+               if (LOG_PRI(pri) < G.logLevel)
+                       timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
        }
 }
 
-static void quit_signal(int sig)
-{
-       timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)"syslogd exiting", 0);
-       puts("syslogd exiting");
-       if (ENABLE_FEATURE_IPC_SYSLOG)
-               ipcsyslog_cleanup();
-       exit(1);
-}
-
 #ifdef SYSLOGD_MARK
 static void do_mark(int sig)
 {
        if (G.markInterval) {
-               timestamp_and_log(LOG_SYSLOG | LOG_INFO, (char*)"-- MARK --", 0);
+               timestamp_and_log_internal("-- MARK --");
                alarm(G.markInterval);
        }
 }
 #endif
 
-static void do_syslogd(void) ATTRIBUTE_NORETURN;
-static void do_syslogd(void)
+/* Don't inline: prevent struct sockaddr_un to take up space on stack
+ * permanently */
+static NOINLINE int create_socket(void)
 {
        struct sockaddr_un sunx;
        int sock_fd;
-       fd_set fds;
        char *dev_log_name;
 
-       /* 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
-#ifdef SYSLOGD_MARK
-       signal(SIGALRM, do_mark);
-       alarm(G.markInterval);
+#if ENABLE_FEATURE_SYSTEMD
+       if (sd_listen_fds() == 1)
+               return SD_LISTEN_FDS_START;
 #endif
-       remove_pidfile("/var/run/syslogd.pid");
 
        memset(&sunx, 0, sizeof(sunx));
        sunx.sun_family = AF_UNIX;
-       strcpy(sunx.sun_path, "/dev/log");
 
        /* Unlink old /dev/log or object it points to. */
        /* (if it exists, bind will fail) */
-       logmode = LOGMODE_NONE;
-       dev_log_name = xmalloc_readlink_or_warn("/dev/log");
-       logmode = LOGMODE_STDIO;
+       strcpy(sunx.sun_path, "/dev/log");
+       dev_log_name = xmalloc_follow_symlinks("/dev/log");
        if (dev_log_name) {
-               int fd = xopen(".", O_NONBLOCK);
-               xchdir("/dev");
-               /* we do not check whether this is a link also */
-               unlink(dev_log_name);
-               fchdir(fd);
-               close(fd);
                safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
                free(dev_log_name);
-       } else {
-               unlink("/dev/log");
        }
+       unlink(sunx.sun_path);
 
        sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
        xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
+       chmod("/dev/log", 0666);
 
-       if (chmod("/dev/log", 0666) < 0) {
-               bb_perror_msg_and_die("cannot set permission on /dev/log");
+       return sock_fd;
+}
+
+#if ENABLE_FEATURE_REMOTE_LOG
+static int try_to_resolve_remote(remoteHost_t *rh)
+{
+       if (!rh->remoteAddr) {
+               unsigned now = monotonic_sec();
+
+               /* Don't resolve name too often - DNS timeouts can be big */
+               if ((now - rh->last_dns_resolve) < DNS_WAIT_SEC)
+                       return -1;
+               rh->last_dns_resolve = now;
+               rh->remoteAddr = host2sockaddr(rh->remoteHostname, 514);
+               if (!rh->remoteAddr)
+                       return -1;
        }
+       return xsocket(rh->remoteAddr->u.sa.sa_family, SOCK_DGRAM, 0);
+}
+#endif
+
+static void do_syslogd(void) NORETURN;
+static void do_syslogd(void)
+{
+       int sock_fd;
+#if ENABLE_FEATURE_REMOTE_LOG
+       llist_t *item;
+#endif
+#if ENABLE_FEATURE_SYSLOGD_DUP
+       int last_sz = -1;
+       char *last_buf;
+       char *recvbuf = G.recvbuf;
+#else
+#define recvbuf (G.recvbuf)
+#endif
+
+       /* Set up signal handlers (so that they interrupt read()) */
+       signal_no_SA_RESTART_empty_mask(SIGTERM, record_signo);
+       signal_no_SA_RESTART_empty_mask(SIGINT, record_signo);
+       //signal_no_SA_RESTART_empty_mask(SIGQUIT, record_signo);
+       signal(SIGHUP, SIG_IGN);
+#ifdef SYSLOGD_MARK
+       signal(SIGALRM, do_mark);
+       alarm(G.markInterval);
+#endif
+       sock_fd = create_socket();
+
        if (ENABLE_FEATURE_IPC_SYSLOG && (option_mask32 & OPT_circularlog)) {
                ipcsyslog_init();
        }
 
-       timestamp_and_log(LOG_SYSLOG | LOG_INFO,
-                       (char*)"syslogd started: BusyBox v" BB_VER, 0);
+       timestamp_and_log_internal("syslogd started: BusyBox v" BB_VER);
 
-       for (;;) {
-               FD_ZERO(&fds);
-               FD_SET(sock_fd, &fds);
+       while (!bb_got_signal) {
+               ssize_t sz;
 
-               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 ENABLE_FEATURE_SYSLOGD_DUP
+               last_buf = recvbuf;
+               if (recvbuf == G.recvbuf)
+                       recvbuf = G.recvbuf + MAX_READ;
+               else
+                       recvbuf = G.recvbuf;
+#endif
+ read_again:
+               sz = read(sock_fd, recvbuf, MAX_READ - 1);
+               if (sz < 0) {
+                       if (!bb_got_signal)
+                               bb_perror_msg("read from /dev/log");
+                       break;
                }
 
-               if (FD_ISSET(sock_fd, &fds)) {
-                       int i;
-                       i = recv(sock_fd, G.recvbuf, MAX_READ - 1, 0);
-                       if (i <= 0)
-                               bb_perror_msg_and_die("UNIX socket error");
-                       /* TODO: maybe suppress duplicates? */
+               /* Drop trailing '\n' and NULs (typically there is one NUL) */
+               while (1) {
+                       if (sz == 0)
+                               goto read_again;
+                       /* man 3 syslog says: "A trailing newline is added when needed".
+                        * However, neither glibc nor uclibc do this:
+                        * syslog(prio, "test")   sends "test\0" to /dev/log,
+                        * syslog(prio, "test\n") sends "test\n\0".
+                        * IOW: newline is passed verbatim!
+                        * I take it to mean that it's syslogd's job
+                        * to make those look identical in the log files. */
+                       if (recvbuf[sz-1] != '\0' && recvbuf[sz-1] != '\n')
+                               break;
+                       sz--;
+               }
+#if ENABLE_FEATURE_SYSLOGD_DUP
+               if ((option_mask32 & OPT_dup) && (sz == last_sz))
+                       if (memcmp(last_buf, recvbuf, sz) == 0)
+                               continue;
+               last_sz = sz;
+#endif
 #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 (G.remoteAddr) {
-                               if (-1 == G.remoteFD) {
-                                       G.remoteFD = socket(G.remoteAddr->sa.sa_family, SOCK_DGRAM, 0);
-                               }
-                               if (-1 != G.remoteFD) {
-                                       /* send message to remote logger, ignore possible error */
-                                       sendto(G.remoteFD, G.recvbuf, i, MSG_DONTWAIT,
-                                               &G.remoteAddr->sa, G.remoteAddr->len);
+               /* Stock syslogd sends it '\n'-terminated
+                * over network, mimic that */
+               recvbuf[sz] = '\n';
+
+               /* We are not modifying log messages in any way before send */
+               /* Remote site cannot trust _us_ anyway and need to do validation again */
+               for (item = G.remoteHosts; item != NULL; item = item->link) {
+                       remoteHost_t *rh = (remoteHost_t *)item->data;
+
+                       if (rh->remoteFD == -1) {
+                               rh->remoteFD = try_to_resolve_remote(rh);
+                               if (rh->remoteFD == -1)
+                                       continue;
+                       }
+
+                       /* Send message to remote logger.
+                        * On some errors, close and set remoteFD to -1
+                        * so that DNS resolution is retried.
+                        */
+                       if (sendto(rh->remoteFD, recvbuf, sz+1,
+                                       MSG_DONTWAIT | MSG_NOSIGNAL,
+                                       &(rh->remoteAddr->u.sa), rh->remoteAddr->len) == -1
+                       ) {
+                               switch (errno) {
+                               case ECONNRESET:
+                               case ENOTCONN: /* paranoia */
+                               case EPIPE:
+                                       close(rh->remoteFD);
+                                       rh->remoteFD = -1;
+                                       free(rh->remoteAddr);
+                                       rh->remoteAddr = NULL;
                                }
                        }
+               }
 #endif
-                       G.recvbuf[i] = '\0';
-                       split_escape_and_log(G.recvbuf, i);
-               } /* FD_ISSET() */
-       } /* for */
+               if (!ENABLE_FEATURE_REMOTE_LOG || (option_mask32 & OPT_locallog)) {
+                       recvbuf[sz] = '\0'; /* ensure it *is* NUL terminated */
+                       split_escape_and_log(recvbuf, sz);
+               }
+       } /* while (!bb_got_signal) */
+
+       timestamp_and_log_internal("syslogd exiting");
+       puts("syslogd exiting");
+       if (ENABLE_FEATURE_IPC_SYSLOG)
+               ipcsyslog_cleanup();
+       kill_myself_with_sig(bb_got_signal);
+#undef recvbuf
 }
 
-int syslogd_main(int argc, char **argv);
-int syslogd_main(int argc, char **argv)
+int syslogd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int syslogd_main(int argc UNUSED_PARAM, char **argv)
 {
+       int opts;
        char OPTION_DECL;
-       char *p;
+#if ENABLE_FEATURE_REMOTE_LOG
+       llist_t *remoteAddrList = NULL;
+#endif
+
+       INIT_G();
 
-       PTR_TO_GLOBALS = memcpy(xzalloc(sizeof(G)), &init_data, sizeof(init_data));
+       /* No non-option params, -R can occur multiple times */
+       opt_complementary = "=0" IF_FEATURE_REMOTE_LOG(":R::");
+       opts = getopt32(argv, OPTION_STR, OPTION_PARAM);
+#if ENABLE_FEATURE_REMOTE_LOG
+       while (remoteAddrList) {
+               remoteHost_t *rh = xzalloc(sizeof(*rh));
+               rh->remoteHostname = llist_pop(&remoteAddrList);
+               rh->remoteFD = -1;
+               rh->last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
+               llist_add_to(&G.remoteHosts, rh);
+       }
+#endif
 
-       /* do normal option parsing */
-       opt_complementary = "=0"; /* no non-option params */
-       getopt32(argc, argv, OPTION_STR, OPTION_PARAM);
 #ifdef SYSLOGD_MARK
-       if (option_mask32 & OPT_mark) // -m
+       if (opts & OPT_mark) // -m
                G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
 #endif
-       //if (option_mask32 & OPT_nofork) // -n
-       //if (option_mask32 & OPT_outfile) // -O
-       if (option_mask32 & OPT_loglevel) // -l
+       //if (opts & OPT_nofork) // -n
+       //if (opts & OPT_outfile) // -O
+       if (opts & OPT_loglevel) // -l
                G.logLevel = xatou_range(opt_l, 1, 8);
-       //if (option_mask32 & OPT_small) // -S
+       //if (opts & OPT_small) // -S
 #if ENABLE_FEATURE_ROTATE_LOGFILE
-       if (option_mask32 & OPT_filesize) // -s
+       if (opts & OPT_filesize) // -s
                G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
-       if (option_mask32 & OPT_rotatecnt) // -b
+       if (opts & OPT_rotatecnt) // -b
                G.logFileRotate = xatou_range(opt_b, 0, 99);
 #endif
-#if ENABLE_FEATURE_REMOTE_LOG
-       if (option_mask32 & OPT_remotelog) { // -R
-               G.remoteAddr = xhost2sockaddr(opt_R, 514);
-       }
-       //if (option_mask32 & OPT_locallog) // -L
-#endif
 #if ENABLE_FEATURE_IPC_SYSLOG
        if (opt_C) // -Cn
                G.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))
+       if (ENABLE_FEATURE_REMOTE_LOG && !(opts & OPT_remotelog)) // -R
                option_mask32 |= OPT_locallog;
 
        /* Store away localhost's name before the fork */
-       gethostname(G.localHostName, sizeof(G.localHostName));
-       p = strchr(G.localHostName, '.');
-       if (p) {
-               *p = '\0';
-       }
+       G.hostname = safe_gethostname();
+       *strchrnul(G.hostname, '.') = '\0';
 
-       if (!(option_mask32 & OPT_nofork)) {
+       if (!(opts & OPT_nofork)) {
                bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
        }
-       umask(0);
+       //umask(0); - why??
        write_pidfile("/var/run/syslogd.pid");
        do_syslogd();
        /* return EXIT_SUCCESS; */
 }
+
+/* Clean up. Needed because we are included from syslogd_and_logger.c */
+#undef DEBUG
+#undef SYSLOGD_MARK
+#undef SYSLOGD_WRLOCK
+#undef G
+#undef GLOBALS
+#undef INIT_G
+#undef OPTION_STR
+#undef OPTION_DECL
+#undef OPTION_PARAM