#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <strings.h>
#include <errno.h>
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#define BUFSIZE 4096
#define DEBUG(...)
//#define DEBUG(...) printf(__VA_ARGS__)

static char pri[8][7] = {
    "emerg", "alert", "crit", "error", "warn", "notice", "info", "debug"
};

static char fac[24][9] = {
    "kern", "user", "mail", "daemon", "auth", "syslog", "lpr", "news", "uucp",
    "cron", "authpriv", "ftp", "kern1", "kern2", "kern3", "kern4", "local0",
    "local1", "local2", "local3", "local4", "local5", "local6", "local7"
};

void failerr(char *what, int when) {
    if (when == -1) {
        perror(what);
        exit(1);
    }
}

void handle_log(char *entry) {
    char *p, c;
    int facpriv = 0;
    p = entry;
    if (*p == '<') {
        while(isdigit(*++p)) {
            facpriv = 10 * facpriv + *p -'0';
        }
        if (*p == '>') {
            ++p;
        }
    }

    printf("<%s.%s> %s\n", fac[facpriv >> 3], pri[facpriv & 7], p);
}

int main() {
    unsigned int fd_listen;
    struct sockaddr_un local;
    char buf[BUFSIZE];

    local.sun_family = AF_UNIX;
    strcpy(local.sun_path, "/dev/log");
    unlink(local.sun_path);

    failerr("socket", (fd_listen = socket(AF_UNIX, SOCK_STREAM, 0)));
    failerr("bind", bind(fd_listen, (struct sockaddr *)&local,
        strlen(local.sun_path) + sizeof(local.sun_family)));
    failerr("listen", listen(fd_listen, 5));

    for(;;) {
        int done, fd_conn, n, t;
        struct sockaddr_un remote;
        t = sizeof(remote);
        failerr("accept", (fd_conn = accept(fd_listen, (struct sockaddr *)&remote, &t)));
        DEBUG("Accepted connection\n");
        done = 0;
        do {
            n = recv(fd_conn, buf, BUFSIZE, 0);
            DEBUG("Received %d bytes of input\n", n);
            if (n <= 0) {
                if (n < 0) perror("recv");
                done = 1;
                DEBUG("Want to close\n");
            } else {
                buf[n] = '\0';
                handle_log(buf);
            }
        } while (!done);
        close(fd_conn);
        DEBUG("Closed connection\n");
    }
}