/* tinyproxy - A fast light-weight HTTP proxy
 * Copyright (C) 1998 Steven Young <sdyoung@miranda.org>
 * Copyright (C) 1999 Robert James Kaes <rjkaes@users.sourceforge.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/* Logs the various messages which tinyproxy produces to either a log file
 * or the syslog daemon. Not much to it...
 */

#include "main.h"

#include "heap.h"
#include "log.h"
#include "utils.h"
#include "vector.h"

static const char *syslog_level[] = {
        NULL,
        NULL,
        "CRITICAL",
        "ERROR",
        "WARNING",
        "NOTICE",
        "INFO",
        "DEBUG",
        "CONNECT"
};

#define TIME_LENGTH 16
#define STRING_LENGTH 800

/*
 * Global file descriptor for the log file
 */
int log_file_fd = -1;

/*
 * Store the log level setting.
 */
static int log_level = LOG_INFO;

/*
 * Hold a listing of log messages which need to be sent once the log
 * file has been established.
 * The key is the actual messages (already filled in full), and the value
 * is the log level.
 */
static vector_t log_message_storage;

/*
 * Open the log file and store the file descriptor in a global location.
 */
int open_log_file (const char *log_file_name)
{
        log_file_fd = create_file_safely (log_file_name, FALSE);
        return log_file_fd;
}

/*
 * Close the log file
 */
void close_log_file (void)
{
        close (log_file_fd);
}

/*
 * Truncate log file to a zero length.
 */
void truncate_log_file (void)
{
        lseek (log_file_fd, 0, SEEK_SET);
        if (ftruncate (log_file_fd, 0) != 0) {
                log_message (LOG_WARNING,
                             "Unable to truncate log file to zero length");
	}
}

/*
 * Set the log level for writing to the log file.
 */
void set_log_level (int level)
{
        log_level = level;
}

/*
 * This routine logs messages to either the log file or the syslog function.
 */
void log_message (int level, const char *fmt, ...)
{
        va_list args;
        time_t nowtime;

        char time_string[TIME_LENGTH];
        char str[STRING_LENGTH];

        ssize_t ret;

#ifdef NDEBUG
        /*
         * Figure out if we should write the message or not.
         */
        if (log_level == LOG_CONN) {
                if (level == LOG_INFO)
                        return;
        } else if (log_level == LOG_INFO) {
                if (level > LOG_INFO && level != LOG_CONN)
                        return;
        } else if (level > log_level)
                return;
#endif

#ifdef HAVE_SYSLOG_H
        if (config.syslog && level == LOG_CONN)
                level = LOG_INFO;
#endif

        va_start (args, fmt);

        /*
         * If the config file hasn't been processed, then we need to store
         * the messages for later processing.
         */
        if (!processed_config_file) {
                char *entry_buffer;

                if (!log_message_storage) {
                        log_message_storage = vector_create ();
                        if (!log_message_storage)
                                goto out;
                }

                vsnprintf (str, STRING_LENGTH, fmt, args);

                entry_buffer = (char *) safemalloc (strlen (str) + 6);
                if (!entry_buffer)
                        goto out;

                sprintf (entry_buffer, "%d %s", level, str);
                vector_append (log_message_storage, entry_buffer,
                               strlen (entry_buffer) + 1);

                safefree (entry_buffer);
                goto out;
        }
#ifdef HAVE_SYSLOG_H
        if (config.syslog) {
#  ifdef HAVE_VSYSLOG_H
                vsyslog (level, fmt, args);
#  else
                vsnprintf (str, STRING_LENGTH, fmt, args);
                syslog (level, "%s", str);
#  endif
        } else {
#endif
                nowtime = time (NULL);
                /* Format is month day hour:minute:second (24 time) */
                strftime (time_string, TIME_LENGTH, "%b %d %H:%M:%S",
                          localtime (&nowtime));

                snprintf (str, STRING_LENGTH, "%-9s %s [%ld]: ",
                          syslog_level[level], time_string,
                          (long int) getpid ());

                assert (log_file_fd >= 0);

                ret = write (log_file_fd, str, strlen (str));
                if (ret == -1) {
                        log_message (LOG_WARNING,
                                     "Could not write to log file");
                }

                vsnprintf (str, STRING_LENGTH, fmt, args);
                ret = write (log_file_fd, str, strlen (str));
                if (ret == -1) {
                        log_message (LOG_WARNING,
                                     "Could not write to log file");
                }

                ret = write (log_file_fd, "\n", 1);
                if (ret == -1) {
                        log_message (LOG_WARNING,
                                     "Could not write to log file");
                }

                fsync (log_file_fd);

#ifdef HAVE_SYSLOG_H
        }
#endif

out:
        va_end (args);
}

/*
 * This needs to send any stored log messages.
 */
void send_stored_logs (void)
{
        char *string;
        char *ptr;

        int level;

        size_t i;

        for (i = 0; (ssize_t) i != vector_length (log_message_storage); ++i) {
                string =
                    (char *) vector_getentry (log_message_storage, i, NULL);

                ptr = strchr (string, ' ') + 1;
                level = atoi (string);

#ifdef NDEBUG
                if (log_level == LOG_CONN && level == LOG_INFO)
                        continue;
                else if (log_level == LOG_INFO) {
                        if (level > LOG_INFO && level != LOG_CONN)
                                continue;
                } else if (level > log_level)
                        continue;
#endif

                log_message (level, ptr);
        }

        vector_delete (log_message_storage);
        log_message_storage = NULL;
}