/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009-2010 The FreeBSD Foundation
 * Copyright (c) 2011 Pawel Jakub Dawidek <pjd@FreeBSD.org>
 * All rights reserved.
 *
 * This software was developed by Pawel Jakub Dawidek under sponsorship from
 * the FreeBSD Foundation.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <assert.h>
#include <errno.h>
#include <libutil.h>
#include <printf.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>

#include "pjdlog.h"

#define PJDLOG_NEVER_INITIALIZED        0
#define PJDLOG_NOT_INITIALIZED          1
#define PJDLOG_INITIALIZED              2

static int pjdlog_initialized = PJDLOG_NEVER_INITIALIZED;
static int pjdlog_mode, pjdlog_debug_level;
static char pjdlog_prefix[128];

static int
pjdlog_printf_arginfo_humanized_number(const struct printf_info *pi __unused,
    size_t n, int *argt)
{

        assert(n >= 1);
        argt[0] = PA_INT | PA_FLAG_INTMAX;
        return (1);
}

static int
pjdlog_printf_render_humanized_number(struct __printf_io *io,
    const struct printf_info *pi, const void * const *arg)
{
        char buf[5];
        intmax_t num;
        int ret;

        num = *(const intmax_t *)arg[0];
        humanize_number(buf, sizeof(buf), (int64_t)num, "", HN_AUTOSCALE,
            HN_NOSPACE | HN_DECIMAL);
        ret = __printf_out(io, pi, buf, strlen(buf));
        __printf_flush(io);
        return (ret);
}

static int
pjdlog_printf_arginfo_sockaddr(const struct printf_info *pi __unused,
    size_t n, int *argt)
{

        assert(n >= 1);
        argt[0] = PA_POINTER;
        return (1);
}

static int
pjdlog_printf_render_sockaddr(struct __printf_io *io,
    const struct printf_info *pi, const void * const *arg)
{
        const struct sockaddr_storage *ss;
        char buf[64];
        int ret;

        ss = *(const struct sockaddr_storage * const *)arg[0];
        switch (ss->ss_family) {
        case AF_INET:
            {
                char addr[INET_ADDRSTRLEN];
                const struct sockaddr_in *sin;
                unsigned int port;

                sin = (const struct sockaddr_in *)ss;
                port = ntohs(sin->sin_port);
                if (inet_ntop(ss->ss_family, &sin->sin_addr, addr,
                    sizeof(addr)) == NULL) {
                        PJDLOG_ABORT("inet_ntop(AF_INET) failed: %s.",
                            strerror(errno));
                }
                snprintf(buf, sizeof(buf), "%s:%u", addr, port);
                break;
            }
        case AF_INET6:
            {
                char addr[INET6_ADDRSTRLEN];
                const struct sockaddr_in6 *sin;
                unsigned int port;

                sin = (const struct sockaddr_in6 *)ss;
                port = ntohs(sin->sin6_port);
                if (inet_ntop(ss->ss_family, &sin->sin6_addr, addr,
                    sizeof(addr)) == NULL) {
                        PJDLOG_ABORT("inet_ntop(AF_INET6) failed: %s.",
                            strerror(errno));
                }
                snprintf(buf, sizeof(buf), "[%s]:%u", addr, port);
                break;
            }
        default:
                snprintf(buf, sizeof(buf), "[unsupported family %hhu]",
                    ss->ss_family);
                break;
        }
        ret = __printf_out(io, pi, buf, strlen(buf));
        __printf_flush(io);
        return (ret);
}

void
pjdlog_init(int mode)
{
        int saved_errno;

        assert(pjdlog_initialized == PJDLOG_NEVER_INITIALIZED ||
            pjdlog_initialized == PJDLOG_NOT_INITIALIZED);
        assert(mode == PJDLOG_MODE_STD || mode == PJDLOG_MODE_SYSLOG);

        saved_errno = errno;

        if (pjdlog_initialized == PJDLOG_NEVER_INITIALIZED) {
                __use_xprintf = 1;
                register_printf_render_std("T");
                register_printf_render('N',
                    pjdlog_printf_render_humanized_number,
                    pjdlog_printf_arginfo_humanized_number);
                register_printf_render('S',
                    pjdlog_printf_render_sockaddr,
                    pjdlog_printf_arginfo_sockaddr);
        }

        if (mode == PJDLOG_MODE_SYSLOG)
                openlog(NULL, LOG_PID | LOG_NDELAY, LOG_DAEMON);
        pjdlog_mode = mode;
        pjdlog_debug_level = 0;
        bzero(pjdlog_prefix, sizeof(pjdlog_prefix));

        pjdlog_initialized = PJDLOG_INITIALIZED;

        errno = saved_errno;
}

void
pjdlog_fini(void)
{
        int saved_errno;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        saved_errno = errno;

        if (pjdlog_mode == PJDLOG_MODE_SYSLOG)
                closelog();

        pjdlog_initialized = PJDLOG_NOT_INITIALIZED;

        errno = saved_errno;
}

/*
 * Configure where the logs should go.
 * By default they are send to stdout/stderr, but after going into background
 * (eg. by calling daemon(3)) application is responsible for changing mode to
 * PJDLOG_MODE_SYSLOG, so logs will be send to syslog.
 */
void
pjdlog_mode_set(int mode)
{
        int saved_errno;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);
        assert(mode == PJDLOG_MODE_STD || mode == PJDLOG_MODE_SYSLOG);

        if (pjdlog_mode == mode)
                return;

        saved_errno = errno;

        if (mode == PJDLOG_MODE_SYSLOG)
                openlog(NULL, LOG_PID | LOG_NDELAY, LOG_DAEMON);
        else /* if (mode == PJDLOG_MODE_STD) */
                closelog();

        pjdlog_mode = mode;

        errno = saved_errno;
}

/*
 * Return current mode.
 */
int
pjdlog_mode_get(void)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        return (pjdlog_mode);
}

/*
 * Set debug level. All the logs above the level specified here will be
 * ignored.
 */
void
pjdlog_debug_set(int level)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);
        assert(level >= 0);

        pjdlog_debug_level = level;
}

/*
 * Return current debug level.
 */
int
pjdlog_debug_get(void)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        return (pjdlog_debug_level);
}

/*
 * Set prefix that will be used before each log.
 * Setting prefix to NULL will remove it.
 */
void
pjdlog_prefix_set(const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        va_start(ap, fmt);
        pjdlogv_prefix_set(fmt, ap);
        va_end(ap);
}

/*
 * Set prefix that will be used before each log.
 * Setting prefix to NULL will remove it.
 */
void
pjdlogv_prefix_set(const char *fmt, va_list ap)
{
        int saved_errno;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);
        assert(fmt != NULL);

        saved_errno = errno;

        vsnprintf(pjdlog_prefix, sizeof(pjdlog_prefix), fmt, ap);

        errno = saved_errno;
}

/*
 * Convert log level into string.
 */
static const char *
pjdlog_level_string(int loglevel)
{

        switch (loglevel) {
        case LOG_EMERG:
                return ("EMERG");
        case LOG_ALERT:
                return ("ALERT");
        case LOG_CRIT:
                return ("CRIT");
        case LOG_ERR:
                return ("ERROR");
        case LOG_WARNING:
                return ("WARNING");
        case LOG_NOTICE:
                return ("NOTICE");
        case LOG_INFO:
                return ("INFO");
        case LOG_DEBUG:
                return ("DEBUG");
        }
        assert(!"Invalid log level.");
        abort();        /* XXX: gcc */
}

/*
 * Common log routine.
 */
void
pjdlog_common(int loglevel, int debuglevel, int error, const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        va_start(ap, fmt);
        pjdlogv_common(loglevel, debuglevel, error, fmt, ap);
        va_end(ap);
}

/*
 * Common log routine, which can handle regular log level as well as debug
 * level. We decide here where to send the logs (stdout/stderr or syslog).
 */
void
pjdlogv_common(int loglevel, int debuglevel, int error, const char *fmt,
    va_list ap)
{
        int saved_errno;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);
        assert(loglevel == LOG_EMERG || loglevel == LOG_ALERT ||
            loglevel == LOG_CRIT || loglevel == LOG_ERR ||
            loglevel == LOG_WARNING || loglevel == LOG_NOTICE ||
            loglevel == LOG_INFO || loglevel == LOG_DEBUG);
        assert(loglevel != LOG_DEBUG || debuglevel > 0);
        assert(error >= -1);

        /* Ignore debug above configured level. */
        if (loglevel == LOG_DEBUG && debuglevel > pjdlog_debug_level)
                return;

        saved_errno = errno;

        switch (pjdlog_mode) {
        case PJDLOG_MODE_STD:
            {
                FILE *out;

                /*
                 * We send errors and warning to stderr and the rest to stdout.
                 */
                switch (loglevel) {
                case LOG_EMERG:
                case LOG_ALERT:
                case LOG_CRIT:
                case LOG_ERR:
                case LOG_WARNING:
                        out = stderr;
                        break;
                case LOG_NOTICE:
                case LOG_INFO:
                case LOG_DEBUG:
                        out = stdout;
                        break;
                default:
                        assert(!"Invalid loglevel.");
                        abort();        /* XXX: gcc */
                }

                fprintf(out, "[%s]", pjdlog_level_string(loglevel));
                /* Attach debuglevel if this is debug log. */
                if (loglevel == LOG_DEBUG)
                        fprintf(out, "[%d]", debuglevel);
                fprintf(out, " %s", pjdlog_prefix);
                vfprintf(out, fmt, ap);
                if (error != -1)
                        fprintf(out, ": %s.", strerror(error));
                fprintf(out, "\n");
                fflush(out);
                break;
            }
        case PJDLOG_MODE_SYSLOG:
            {
                char log[1024];
                int len;

                len = snprintf(log, sizeof(log), "%s", pjdlog_prefix);
                if ((size_t)len < sizeof(log))
                        len += vsnprintf(log + len, sizeof(log) - len, fmt, ap);
                if (error != -1 && (size_t)len < sizeof(log)) {
                        (void)snprintf(log + len, sizeof(log) - len, ": %s.",
                            strerror(error));
                }
                syslog(loglevel, "%s", log);
                break;
            }
        default:
                assert(!"Invalid mode.");
        }

        errno = saved_errno;
}

/*
 * Regular logs.
 */
void
pjdlogv(int loglevel, const char *fmt, va_list ap)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        /* LOG_DEBUG is invalid here, pjdlogv?_debug() should be used. */
        assert(loglevel == LOG_EMERG || loglevel == LOG_ALERT ||
            loglevel == LOG_CRIT || loglevel == LOG_ERR ||
            loglevel == LOG_WARNING || loglevel == LOG_NOTICE ||
            loglevel == LOG_INFO);

        pjdlogv_common(loglevel, 0, -1, fmt, ap);
}

/*
 * Regular logs.
 */
void
pjdlog(int loglevel, const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        va_start(ap, fmt);
        pjdlogv(loglevel, fmt, ap);
        va_end(ap);
}

/*
 * Debug logs.
 */
void
pjdlogv_debug(int debuglevel, const char *fmt, va_list ap)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        pjdlogv_common(LOG_DEBUG, debuglevel, -1, fmt, ap);
}

/*
 * Debug logs.
 */
void
pjdlog_debug(int debuglevel, const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        va_start(ap, fmt);
        pjdlogv_debug(debuglevel, fmt, ap);
        va_end(ap);
}

/*
 * Error logs with errno logging.
 */
void
pjdlogv_errno(int loglevel, const char *fmt, va_list ap)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        pjdlogv_common(loglevel, 0, errno, fmt, ap);
}

/*
 * Error logs with errno logging.
 */
void
pjdlog_errno(int loglevel, const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        va_start(ap, fmt);
        pjdlogv_errno(loglevel, fmt, ap);
        va_end(ap);
}

/*
 * Log error, errno and exit.
 */
void
pjdlogv_exit(int exitcode, const char *fmt, va_list ap)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        pjdlogv_errno(LOG_ERR, fmt, ap);
        exit(exitcode);
        /* NOTREACHED */
}

/*
 * Log error, errno and exit.
 */
void
pjdlog_exit(int exitcode, const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        va_start(ap, fmt);
        pjdlogv_exit(exitcode, fmt, ap);
        /* NOTREACHED */
        va_end(ap);
}

/*
 * Log error and exit.
 */
void
pjdlogv_exitx(int exitcode, const char *fmt, va_list ap)
{

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        pjdlogv(LOG_ERR, fmt, ap);
        exit(exitcode);
        /* NOTREACHED */
}

/*
 * Log error and exit.
 */
void
pjdlog_exitx(int exitcode, const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        va_start(ap, fmt);
        pjdlogv_exitx(exitcode, fmt, ap);
        /* NOTREACHED */
        va_end(ap);
}

/*
 * Log failure message and exit.
 */
void
pjdlog_abort(const char *func, const char *file, int line,
    const char *failedexpr, const char *fmt, ...)
{
        va_list ap;

        assert(pjdlog_initialized == PJDLOG_INITIALIZED);

        /*
         * When there is no message we pass __func__ as 'fmt'.
         * It would be cleaner to pass NULL or "", but gcc generates a warning
         * for both of those.
         */
        if (fmt != func) {
                va_start(ap, fmt);
                pjdlogv_critical(fmt, ap);
                va_end(ap);
        }
        if (failedexpr == NULL) {
                if (func == NULL) {
                        pjdlog_critical("Aborted at file %s, line %d.", file,
                            line);
                } else {
                        pjdlog_critical("Aborted at function %s, file %s, line %d.",
                            func, file, line);
                }
        } else {
                if (func == NULL) {
                        pjdlog_critical("Assertion failed: (%s), file %s, line %d.",
                            failedexpr, file, line);
                } else {
                        pjdlog_critical("Assertion failed: (%s), function %s, file %s, line %d.",
                            failedexpr, func, file, line);
                }
        }
        abort();
}