/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/capsicum.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <capsicum_helpers.h>
#include <ctype.h>
#include <err.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <libcasper.h>
#include <casper/cap_syslog.h>

#define SYSLOG_NAMES
#include <syslog.h>

#define sstosa(ss)      ((struct sockaddr *)(void *)ss)

struct socks {
        int sk_sock;
        int sk_addrlen;
        struct sockaddr_storage sk_addr;
};

static int      decode(char *, const CODE *);
static int      pencode(char *);
static ssize_t  socksetup(const char *, const char *, const char *,
                    struct socks **);
static void     logmessage(int, const char *, const char *, const char *,
                    struct socks *, ssize_t, const char *);
static void     usage(void);

static cap_channel_t *capsyslog;
#ifdef INET6
static int family = PF_UNSPEC;  /* protocol family (IPv4, IPv6 or both) */
#else
static int family = PF_INET;    /* protocol family (IPv4 only) */
#endif
static int send_to_all = 0;     /* send message to all IPv4/IPv6 addresses */

/*
 * logger -- read and log utility
 *
 *      Reads from an input and arranges to write the result on the system
 *      log.
 */
int
main(int argc, char *argv[])
{
        cap_channel_t *capcas;
        struct socks *socks;
        ssize_t nsock;
        time_t now;
        int ch, logflags, pri;
        char *tag, *host, buf[1024], *timestamp, tbuf[26],
            *hostname, hbuf[MAXHOSTNAMELEN], *pristr;
        const char *svcname, *src;

        tag = NULL;
        host = NULL;
        hostname = NULL;
        svcname = "syslog";
        src = NULL;
        socks = NULL;
        pri = LOG_USER | LOG_NOTICE;
        pristr = NULL;
        logflags = 0;
        unsetenv("TZ");
        while ((ch = getopt(argc, argv, "46Af:H:h:iP:p:S:st:")) != -1)
                switch((char)ch) {
                case '4':
                        family = PF_INET;
                        break;
#ifdef INET6
                case '6':
                        family = PF_INET6;
                        break;
#endif
                case 'A':
                        send_to_all++;
                        break;
                case 'f':               /* file to log */
                        if (freopen(optarg, "r", stdin) == NULL)
                                err(1, "%s", optarg);
                        setvbuf(stdin, 0, _IONBF, 0);
                        break;
                case 'H':               /* hostname to set in message header */
                        hostname = optarg;
                        break;
                case 'h':               /* hostname to deliver to */
                        host = optarg;
                        break;
                case 'i':               /* log process id also */
                        logflags |= LOG_PID;
                        break;
                case 'P':               /* service name or port number */
                        svcname = optarg;
                        break;
                case 'p':               /* priority */
                        pristr = optarg;
                        break;
                case 's':               /* log to standard error */
                        logflags |= LOG_PERROR;
                        break;
                case 'S':               /* source address */
                        src = optarg;
                        break;
                case 't':               /* tag */
                        tag = optarg;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (host) {
                nsock = socksetup(src, host, svcname, &socks);
                if (nsock <= 0)
                        errx(1, "socket");
        } else {
                if (src)
                        errx(1, "-h option is missing.");
                nsock = 0;
        }

        capcas = cap_init();
        if (capcas == NULL)
                err(1, "Unable to contact Casper");
        caph_cache_catpages();
        caph_cache_tzdata();
        if (nsock == 0) {
                if (caph_enter_casper() < 0)
                        err(1, "Unable to enter capability mode");
        }
        capsyslog = cap_service_open(capcas, "system.syslog");
        if (capsyslog == NULL)
                err(1, "Unable to open system.syslog service");
        cap_close(capcas);

        if (pristr != NULL)
                pri = pencode(pristr);
        if (tag == NULL)
                tag = getlogin();
        /* setup for logging */
        if (host == NULL)
                cap_openlog(capsyslog, tag, logflags, 0);

        if (hostname == NULL) {
                hostname = hbuf;
                (void )gethostname(hbuf, MAXHOSTNAMELEN);
                *strchrnul(hostname, '.') = '\0';
        }

        timestamp = tbuf + 4;

        /* log input line if appropriate */
        if (argc > 0) {
                char *p, *endp;
                size_t len;

                (void )time(&now);
                (void )ctime_r(&now, tbuf);
                tbuf[19] = '\0';

                for (p = buf, endp = buf + sizeof(buf) - 2; *argv;) {
                        len = strlen(*argv);
                        if (p + len > endp && p > buf) {
                                logmessage(pri, timestamp, hostname, tag,
                                    socks, nsock, buf);
                                p = buf;
                        }
                        if (len > sizeof(buf) - 1)
                                logmessage(pri, timestamp, hostname, tag,
                                    socks, nsock, *argv++);
                        else {
                                if (p != buf)
                                        *p++ = ' ';
                                bcopy(*argv++, p, len);
                                *(p += len) = '\0';
                        }
                }
                if (p != buf)
                        logmessage(pri, timestamp, hostname, tag, socks, nsock,
                            buf);
        } else
                while (fgets(buf, sizeof(buf), stdin) != NULL) {
                        (void )time(&now);
                        (void )ctime_r(&now, tbuf);
                        tbuf[19] = '\0';

                        logmessage(pri, timestamp, hostname, tag, socks, nsock,
                            buf);
                }
        exit(0);
}

static ssize_t
socksetup(const char *src, const char *dst, const char *svcname,
        struct socks **socks)
{
        struct addrinfo hints, *res, *res0;
        struct sockaddr_storage *ss_src[AF_MAX];
        struct socks *sk;
        ssize_t nsock = 0;
        int error, maxs;

        memset(&ss_src[0], 0, sizeof(ss_src));
        if (src) {
                char *p, *p0, *hs, *hbuf, *sbuf;

                hbuf = sbuf = NULL;
                p0 = p = strdup(src);
                if (p0 == NULL)
                        err(1, "strdup failed");
                hs = p0;        /* point to search ":" */ 
#ifdef INET6
                /* -S option supports IPv6 addr in "[2001:db8::1]:service". */
                if (*p0 == '[') {
                        p = strchr(p0, ']');
                        if (p == NULL)
                                errx(1, "\"]\" not found in src addr");
                        *p = '\0';
                        /* hs points just after ']' (':' or '\0'). */
                        hs = p + 1;
                        /*
                         * p points just after '[' while it points hs
                         * in the case of [].
                         */
                        p = ((p0 + 1) == (hs - 1)) ? hs : p0 + 1;
                }
#endif
                if (*p != '\0') {
                        /* (p == hs) means ":514" or "[]:514". */
                        hbuf = (p == hs && *p == ':') ? NULL : p;
                        p = strchr(hs, ':');
                        if (p != NULL) {
                                *p = '\0';
                                sbuf = (*(p + 1) != '\0') ? p + 1 : NULL;
                        }
                }
                hints = (struct addrinfo){
                        .ai_family = family,
                        .ai_socktype = SOCK_DGRAM,
                        .ai_flags = AI_PASSIVE
                };
                error = getaddrinfo(hbuf, sbuf, &hints, &res0);
                if (error)
                        errx(1, "%s: %s", gai_strerror(error), src);
                for (res = res0; res; res = res->ai_next) {
                        switch (res->ai_family) {
                        case AF_INET:
#ifdef INET6
                        case AF_INET6:
#endif
                                if (ss_src[res->ai_family] != NULL)
                                        continue;
                                ss_src[res->ai_family] =
                                    malloc(sizeof(struct sockaddr_storage));
                                if (ss_src[res->ai_family] == NULL)
                                        err(1, "malloc failed");
                                memcpy(ss_src[res->ai_family], res->ai_addr,
                                    res->ai_addrlen);
                        }
                }
                freeaddrinfo(res0);
                free(p0);
        }

        /* resolve hostname */
        hints = (struct addrinfo){
                .ai_family = family,
                .ai_socktype = SOCK_DGRAM
        };
        error = getaddrinfo(dst, svcname, &hints, &res0);
        if (error == EAI_SERVICE) {
                warnx("%s/udp: unknown service", svcname);
                error = getaddrinfo(dst, "514", &hints, &res0);
        }       
        if (error)
                errx(1, "%s: %s", gai_strerror(error), dst);
        /* count max number of sockets we may open */
        maxs = 0;
        for (res = res0; res; res = res->ai_next)
                maxs++;
        sk = calloc(maxs, sizeof(*sk));
        if (sk == NULL)
                errx(1, "couldn't allocate memory for sockets");
        for (res = res0; res; res = res->ai_next) {
                int s;

                s = socket(res->ai_family, res->ai_socktype,
                    res->ai_protocol);
                if (s < 0)
                        continue;
                if (src && ss_src[res->ai_family] == NULL)
                        errx(1, "address family mismatch");
                        
                if (ss_src[res->ai_family]) {
                        error = bind(s, sstosa(ss_src[res->ai_family]),
                                    ss_src[res->ai_family]->ss_len);
                        if (error < 0)
                                err(1, "bind");
                }
                sk[nsock] = (struct socks){
                        .sk_addrlen = res->ai_addrlen,
                        .sk_sock = s
                };
                memcpy(&sk[nsock].sk_addr, res->ai_addr, res->ai_addrlen);
                nsock++;
        }
        freeaddrinfo(res0);

        *socks = sk;
        return (nsock);
}

/*
 *  Send the message to syslog, either on the local host, or on a remote host
 */
static void
logmessage(int pri, const char *timestamp, const char *hostname,
    const char *tag, struct socks *sk, ssize_t nsock, const char *buf)
{
        char *line;
        int len, i, lsent;

        if (nsock == 0) {
                cap_syslog(capsyslog, pri, "%s", buf);
                return;
        }
        if ((len = asprintf(&line, "<%d>%s %s %s: %s", pri, timestamp,
            hostname, tag, buf)) == -1)
                errx(1, "asprintf");

        lsent = -1;
        for (i = 0; i < nsock; i++) {
                lsent = sendto(sk[i].sk_sock, line, len, 0,
                               sstosa(&sk[i].sk_addr), sk[i].sk_addrlen);
                if (lsent == len && !send_to_all)
                        break;
        }
        if (lsent != len) {
                if (lsent == -1)
                        warn("sendto");
                else
                        warnx("sendto: short send - %d bytes", lsent);
        }

        free(line);
}

/*
 *  Decode a symbolic name to a numeric value
 */
static int
pencode(char *s)
{
        char *save;
        int fac, lev;

        for (save = s; *s && *s != '.'; ++s);
        if (*s) {
                *s = '\0';
                fac = decode(save, facilitynames);
                if (fac < 0)
                        errx(1, "unknown facility name: %s", save);
                *s++ = '.';
        }
        else {
                fac = 0;
                s = save;
        }
        lev = decode(s, prioritynames);
        if (lev < 0)
                errx(1, "unknown priority name: %s", save);
        return ((lev & LOG_PRIMASK) | (fac & LOG_FACMASK));
}

static int
decode(char *name, const CODE *codetab)
{
        const CODE *c;

        if (isdigit(*name))
                return (atoi(name));

        for (c = codetab; c->c_name; c++)
                if (!strcasecmp(name, c->c_name))
                        return (c->c_val);

        return (-1);
}

static void
usage(void)
{
        (void)fprintf(stderr, "usage: %s\n",
            "logger [-46Ais] [-f file] [-h host] [-P port] [-p pri] [-t tag]\n"
            "              [-S addr:port] [message ...]"
            );
        exit(1);
}