/* 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.
 */

/*
 * Done in syslogd_and_logger.c:
#include "libbb.h"
#define SYSLOG_NAMES
#define SYSLOG_NAMES_CONST
#include <syslog.h>
*/

#include <paths.h>
#include <sys/un.h>
#include <sys/uio.h>

#if ENABLE_FEATURE_REMOTE_LOG
#include <netinet/in.h>
#endif

#if ENABLE_FEATURE_IPC_SYSLOG
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#endif


#define DEBUG 0

/* MARK code is not very useful, is bloat, and broken:
 * can deadlock if alarmed to make MARK while writing to IPC buffer
 * (semaphores are down but do_mark routine tries to down them again) */
#undef SYSLOGD_MARK

/* Write locking does not seem to be useful either */
#undef SYSLOGD_WRLOCK

enum {
        MAX_READ = 256,
        DNS_WAIT_SEC = 2 * 60,
};

/* Semaphore operation structures */
struct shbuf_ds {
        int32_t size;   /* size of data - 1 */
        int32_t tail;   /* end of message list */
        char data[1];   /* data/messages */
};

/* Allows us to have smaller initializer. Ugly. */
#define GLOBALS \
        const char *logFilePath;                \
        int logFD;                              \
        /* interval between marks in seconds */ \
        /*int markInterval;*/                   \
        /* level of messages to be logged */    \
        int logLevel;                           \
USE_FEATURE_ROTATE_LOGFILE( \
        /* max size of file before rotation */  \
        unsigned logFileSize;                   \
        /* number of rotated message files */   \
        unsigned logFileRotate;                 \
        unsigned curFileSize;                   \
        smallint isRegular;                     \
) \
USE_FEATURE_REMOTE_LOG( \
        /* udp socket for remote logging */     \
        int remoteFD;                           \
        len_and_sockaddr* remoteAddr;           \
) \
USE_FEATURE_IPC_SYSLOG( \
        int shmid; /* ipc shared memory id */   \
        int s_semid; /* ipc semaphore id */     \
        int shm_size;                           \
        struct sembuf SMwup[1];                 \
        struct sembuf SMwdn[3];                 \
)

struct init_globals {
        GLOBALS
};

struct globals {
        GLOBALS

#if ENABLE_FEATURE_REMOTE_LOG
        unsigned last_dns_resolve;
        char *remoteAddrStr;
#endif

#if ENABLE_FEATURE_IPC_SYSLOG
        struct shbuf_ds *shbuf;
#endif
        time_t last_log_time;
        /* localhost's name. We print only first 64 chars */
        char *hostname;

        /* We recv into recvbuf... */
        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];
        /* ...then sprintf into printbuf, adding timestamp (15 chars),
         * host (64), fac.prio (20) to the message */
        /* (growth by: 15 + 64 + 20 + delims = ~110) */
        char printbuf[MAX_READ*2 + 128];
};

static const struct init_globals init_data = {
        .logFilePath = "/var/log/messages",
        .logFD = -1,
#ifdef SYSLOGD_MARK
        .markInterval = 20 * 60,
#endif
        .logLevel = 8,
#if ENABLE_FEATURE_ROTATE_LOGFILE
        .logFileSize = 200 * 1024,
        .logFileRotate = 1,
#endif
#if ENABLE_FEATURE_REMOTE_LOG
        .remoteFD = -1,
#endif
#if ENABLE_FEATURE_IPC_SYSLOG
        .shmid = -1,
        .s_semid = -1,
        .shm_size = ((CONFIG_FEATURE_IPC_SYSLOG_BUFFER_SIZE)*1024), // default shm size
        .SMwup = { {1, -1, IPC_NOWAIT} },
        .SMwdn = { {0, 0}, {1, 0}, {1, +1} },
#endif
};

#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 */
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_remotelog  ,) // -R
        USE_FEATURE_REMOTE_LOG(    OPTBIT_locallog   ,) // -L
        USE_FEATURE_IPC_SYSLOG(    OPTBIT_circularlog,) // -C
        USE_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_remotelog  )) + 0,
        OPT_locallog    = USE_FEATURE_REMOTE_LOG(    (1 << OPTBIT_locallog   )) + 0,
        OPT_circularlog = USE_FEATURE_IPC_SYSLOG(    (1 << OPTBIT_circularlog)) + 0,
        OPT_dup         = USE_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::") \
        USE_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_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(    ,&G.remoteAddrStr) \
        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

/* our shared key (syslogd.c and logread.c must be in sync) */
enum { KEY_ID = 0x414e4547 }; /* "GENA" */

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

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

        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 == (void*) -1L) { /* shmat has bizarre error return */
                bb_perror_msg_and_die("shmat");
        }

        memset(G.shbuf, 0, G.shm_size);
        G.shbuf->size = G.shm_size - offsetof(struct shbuf_ds, data) - 1;
        /*G.shbuf->tail = 0;*/

        // we'll trust the OS to set initial semval to 0 (let's hope)
        G.s_semid = semget(KEY_ID, 2, IPC_CREAT | IPC_EXCL | 1023);
        if (G.s_semid == -1) {
                if (errno == EEXIST) {
                        G.s_semid = semget(KEY_ID, 2, 0);
                        if (G.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)
{
        int old_tail, new_tail;

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

        /* Circular Buffer Algorithm:
         * --------------------------
         * tail == position where to store next syslog message.
         * tail's max value is (shbuf->size - 1)
         * Last byte of buffer is never used and remains NUL.
         */
        len++; /* length with NUL included */
 again:
        old_tail = G.shbuf->tail;
        new_tail = old_tail + len;
        if (new_tail < G.shbuf->size) {
                /* store message, set new tail */
                memcpy(G.shbuf->data + old_tail, msg, len);
                G.shbuf->tail = new_tail;
        } else {
                /* k == available buffer space ahead of old tail */
                int k = G.shbuf->size - old_tail;
                /* copy what fits to the end of buffer, and repeat */
                memcpy(G.shbuf->data + old_tail, msg, k);
                msg += k;
                len -= k;
                G.shbuf->tail = 0;
                goto again;
        }
        if (semop(G.s_semid, G.SMwup, 1) == -1) {
                bb_perror_msg_and_die("SMwup");
        }
        if (DEBUG)
                printf("tail:%d\n", G.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(time_t now, char *msg)
{
#ifdef SYSLOGD_WRLOCK
        struct flock fl;
#endif
        int len = strlen(msg);

#if ENABLE_FEATURE_IPC_SYSLOG
        if ((option_mask32 & OPT_circularlog) && G.shbuf) {
                log_to_shmem(msg, len);
                return;
        }
#endif
        if (G.logFD >= 0) {
                /* 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 = 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(DEV_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;
                        G.isRegular = (fstat(G.logFD, &statf) == 0 && S_ISREG(statf.st_mode));
                        /* bug (mostly harmless): can wrap around if file > 4gb */
                        G.curFileSize = statf.st_size;
                }
#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) {
                if (G.logFileRotate) { /* always 0..99 */
                        int i = strlen(G.logFilePath) + 3 + 1;
                        char oldFile[i];
                        char newFile[i];
                        i = G.logFileRotate - 1;
                        /* rename: f.8 -> f.9; f.7 -> f.8; ... */
                        while (1) {
                                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;
                }
                ftruncate(G.logFD, 0);
        }
        G.curFileSize +=
#endif
                        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)
{
        const 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 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;

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

        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;

        tmpbuf += len;
        while (p < tmpbuf) {
                char c;
                char *q = G.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) && c != '\t') {
                                *q++ = '^';
                                c += '@'; /* ^@, ^A, ^B... */
                        }
                        *q++ = c;
                }
                *q = '\0';

                /* Now log it */
                if (LOG_PRI(pri) < G.logLevel)
                        timestamp_and_log(pri, G.parsebuf, q - G.parsebuf);
        }
}

#ifdef SYSLOGD_MARK
static void do_mark(int sig)
{
        if (G.markInterval) {
                timestamp_and_log_internal("-- MARK --");
                alarm(G.markInterval);
        }
}
#endif

/* 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;
        char *dev_log_name;

        memset(&sunx, 0, sizeof(sunx));
        sunx.sun_family = AF_UNIX;

        /* Unlink old /dev/log or object it points to. */
        /* (if it exists, bind will fail) */
        strcpy(sunx.sun_path, "/dev/log");
        dev_log_name = xmalloc_follow_symlinks("/dev/log");
        if (dev_log_name) {
                safe_strncpy(sunx.sun_path, dev_log_name, sizeof(sunx.sun_path));
                free(dev_log_name);
        }
        unlink(sunx.sun_path);

        sock_fd = xsocket(AF_UNIX, SOCK_DGRAM, 0);
        xbind(sock_fd, (struct sockaddr *) &sunx, sizeof(sunx));
        chmod("/dev/log", 0666);

        return sock_fd;
}

#if ENABLE_FEATURE_REMOTE_LOG
static int try_to_resolve_remote(void)
{
        if (!G.remoteAddr) {
                unsigned now = monotonic_sec();

                /* Don't resolve name too often - DNS timeouts can be big */
                if ((now - G.last_dns_resolve) < DNS_WAIT_SEC)
                        return -1;
                G.last_dns_resolve = now;
                G.remoteAddr = host2sockaddr(G.remoteAddrStr, 514);
                if (!G.remoteAddr)
                        return -1;
        }
        return socket(G.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_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_internal("syslogd started: BusyBox v" BB_VER);

        while (!bb_got_signal) {
                ssize_t sz;

#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;
                }

                /* 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.remoteAddrStr) {
                        if (-1 == G.remoteFD) {
                                G.remoteFD = try_to_resolve_remote();
                                if (-1 == G.remoteFD)
                                        goto no_luck;
                        }
                        /* Stock syslogd sends it '\n'-terminated
                         * over network, mimic that */
                        recvbuf[sz] = '\n';
                        /* send message to remote logger, ignore possible error */
                        /* TODO: on some errors, close and set G.remoteFD to -1
                         * so that DNS resolution and connect is retried? */
                        sendto(G.remoteFD, recvbuf, sz+1, MSG_DONTWAIT,
                                    &G.remoteAddr->u.sa, G.remoteAddr->len);
 no_luck: ;
                }
#endif
                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) MAIN_EXTERNALLY_VISIBLE;
int syslogd_main(int argc UNUSED_PARAM, char **argv)
{
        char OPTION_DECL;
        int opts;

        INIT_G();
#if ENABLE_FEATURE_REMOTE_LOG
        G.last_dns_resolve = monotonic_sec() - DNS_WAIT_SEC - 1;
#endif

        /* do normal option parsing */
        opt_complementary = "=0"; /* no non-option params */
        opts = getopt32(argv, OPTION_STR, OPTION_PARAM);
#ifdef SYSLOGD_MARK
        if (opts & OPT_mark) // -m
                G.markInterval = xatou_range(opt_m, 0, INT_MAX/60) * 60;
#endif
        //if (opts & OPT_nofork) // -n
        //if (opts & OPT_outfile) // -O
        if (opts & OPT_loglevel) // -l
                G.logLevel = xatou_range(opt_l, 1, 8);
        //if (opts & OPT_small) // -S
#if ENABLE_FEATURE_ROTATE_LOGFILE
        if (opts & OPT_filesize) // -s
                G.logFileSize = xatou_range(opt_s, 0, INT_MAX/1024) * 1024;
        if (opts & OPT_rotatecnt) // -b
                G.logFileRotate = xatou_range(opt_b, 0, 99);
#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 && !(opts & OPT_remotelog)) // -R
                option_mask32 |= OPT_locallog;

        /* Store away localhost's name before the fork */
        G.hostname = safe_gethostname();
        *strchrnul(G.hostname, '.') = '\0';

        if (!(opts & OPT_nofork)) {
                bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
        }
        umask(0);
        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