/* tinyproxy - A fast light-weight HTTP proxy
 * Copyright (C) 1998 Steven Young <sdyoung@miranda.org>
 * Copyright (C) 1998-2002 Robert James Kaes <rjkaes@users.sourceforge.net>
 * Copyright (C) 2000 Chris Lightfoot <chris@ex-parrot.com>
 *
 * 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.
 */

/* The initialize routine. Basically sets up all the initial stuff (logfile,
 * listening socket, config options, etc.) and then sits there and loops
 * over the new connections until the daemon is closed. Also has additional
 * functions to handle the "user friendly" aspects of a program (usage,
 * stats, etc.) Like any good program, most of the work is actually done
 * elsewhere.
 */

#include "tinyproxy.h"

#include "anonymous.h"
#include "buffer.h"
#include "conffile.h"
#include "daemon.h"
#include "heap.h"
#include "filter.h"
#include "child.h"
#include "log.h"
#include "reqs.h"
#include "sock.h"
#include "stats.h"
#include "utils.h"

RETSIGTYPE takesig(int sig);

/*
 * Global Structures
 */
struct config_s config;
float load = 0.00;
unsigned int received_sighup = FALSE;   /* boolean */
unsigned int processed_config_file = FALSE;     /* boolean */

/*
 * Handle a signal
 */
RETSIGTYPE
takesig(int sig)
{
        pid_t pid;
        int status;

        switch (sig) {
        case SIGHUP:
                received_sighup = TRUE;
                break;

        case SIGTERM:
                config.quit = TRUE;
                break;

        case SIGCHLD:
                while ((pid = waitpid(-1, &status, WNOHANG)) > 0) ;
                break;
        }

        return;
}

/*
 * Display the version information for the user.
 */
static void
display_version(void)
{
        printf("%s %s (%s)\n", PACKAGE, VERSION, TARGET_SYSTEM);
}

/*
 * Display the copyright and license for this program.
 */
static void
display_license(void)
{
        display_version();

        printf("\
  Copyright 1998       Steven Young (sdyoung@well.com)\n\
  Copyright 1998-2002  Robert James Kaes (rjkaes@users.sourceforge.net)\n\
  Copyright 1999       George Talusan (gstalusan@uwaterloo.ca)\n\
  Copyright 2000       Chris Lightfoot (chris@ex-parrot.com)\n\
\n\
  This program is free software; you can redistribute it and/or modify\n\
  it under the terms of the GNU General Public License as published by\n\
  the Free Software Foundation; either version 2, or (at your option)\n\
  any later version.\n\
\n\
  This program is distributed in the hope that it will be useful,\n\
  but WITHOUT ANY WARRANTY; without even the implied warranty of\n\
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n\
  GNU General Public License for more details.\n\
\n\
  You should have received a copy of the GNU General Public License\n\
  along with this program; if not, write to the Free Software\n\
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.\n");
}

/*
 * Display usage to the user.
 */
static void
display_usage(void)
{
        printf("Usage: %s [options]\n", PACKAGE);
        printf("\
Options:\n\
  -d		Operate in DEBUG mode.\n\
  -c FILE	Use an alternate configuration file.\n\
  -h		Display this usage information.\n\
  -l            Display the license.\n\
  -v            Display the version number.\n");

        /* Display the modes compiled into tinyproxy */
        printf("\nFeatures compiled in:\n");
#ifdef XTINYPROXY_ENABLE
        printf("    XTinyproxy header\n");
#endif                          /* XTINYPROXY */
#ifdef FILTER_ENABLE
        printf("    Filtering\n");
#endif                          /* FILTER_ENABLE */
#ifndef NDEBUG
        printf("    Debugging code\n");
#endif                          /* NDEBUG */
#ifdef TRANSPARENT_PROXY
        printf("    Transparent proxy support\n");
#endif                          /* TRANSPARENT_PROXY */
#ifdef REVERSE_SUPPORT
        printf("    Reverse proxy support\n");
#endif                          /* REVERSE_SUPPORT */
}

static int
get_id (char *str)
{
	char *tstr;

	if (str == NULL)
		return -1;

	tstr = str;
	while (*tstr != 0) {
		if (!isdigit(*tstr))
			return -1;
		tstr++;
	}

	return atoi(str);
}

int
main(int argc, char **argv)
{
        int optch;
        unsigned int godaemon = TRUE;   /* boolean */
        struct passwd *thisuser = NULL;
        struct group *thisgroup = NULL;
        FILE *config_file;

        /*
         * Disable the creation of CORE files right up front.
         */
#if defined(HAVE_SETRLIMIT) && defined(NDEBUG)
        struct rlimit core_limit = { 0, 0 };
        if (setrlimit(RLIMIT_CORE, &core_limit) < 0) {
                fprintf(stderr, "%s: Could not set the core limit to zero.\n",
                        argv[0]);
                exit(EX_SOFTWARE);
        }
#endif                          /* HAVE_SETRLIMIT */

        /* Default configuration file location */
        config.config_file = DEFAULT_CONF_FILE;

        /*
         * Process the various options
         */
        while ((optch = getopt(argc, argv, "c:vldh")) != EOF) {
                switch (optch) {
                case 'v':
                        display_version();
                        exit(EX_OK);
                case 'l':
                        display_license();
                        exit(EX_OK);
                case 'd':
                        godaemon = FALSE;
                        break;
                case 'c':
                        config.config_file = safestrdup(optarg);
                        if (!config.config_file) {
                                fprintf(stderr,
                                        "%s: Could not allocate memory.\n",
                                        argv[0]);
                                exit(EX_SOFTWARE);
                        }
                        break;
                case 'h':
                default:
                        display_usage();
                        exit(EX_OK);
                }
        }

        log_message(LOG_INFO, "Initializing " PACKAGE " ...");

        /*
         * Make sure the HTML error pages array is NULL to begin with.
         * (FIXME: Should have a better API for all this)
         */
        config.errorpages = NULL;

        /*
         * Read in the settings from the config file.
         */
        config_file = fopen(config.config_file, "r");
        if (!config_file) {
                fprintf(stderr,
                        "%s: Could not open configuration file \"%s\".\n",
                        argv[0], config.config_file);
                exit(EX_SOFTWARE);
        }
        if (config_compile() || config_parse(&config, config_file)) {
                fprintf(stderr,
                        "Unable to parse configuration file.  Not starting.\n");
                exit(EX_SOFTWARE);
        }
        fclose(config_file);

        /*
         * Write to a user supplied log file if it's defined.  This
         * will override using the syslog even if syslog is defined.
         */
        if (config.logf_name) {
                if (open_log_file(config.logf_name) < 0) {
                        fprintf(stderr,
                                "%s: Could not create log file.\n", argv[0]);
                        exit(EX_SOFTWARE);
                }
                config.syslog = FALSE;  /* disable syslog */
        } else if (config.syslog) {
                if (godaemon == TRUE)
                        openlog("tinyproxy", LOG_PID, LOG_DAEMON);
                else
                        openlog("tinyproxy", LOG_PID, LOG_USER);
        } else {
                fprintf(stderr,
                        "%s: Either define a logfile or enable syslog logging\n",
                        argv[0]);
                exit(EX_SOFTWARE);
        }

        processed_config_file = TRUE;
        send_stored_logs();

        /*
         * Set the default values if they were not set in the config file.
         */
        if (config.port == 0) {
                fprintf(stderr,
                        "%s: You MUST set a Port in the configuration file.\n",
                        argv[0]);
                exit(EX_SOFTWARE);
        }
        if (!config.stathost) {
                log_message(LOG_INFO, "Setting stathost to \"%s\".",
                            DEFAULT_STATHOST);
                config.stathost = DEFAULT_STATHOST;
        }
        if (!config.user) {
                log_message(LOG_WARNING,
                            "You SHOULD set a UserName in the configuration file. Using current user instead.");
        }
        if (config.idletimeout == 0) {
                log_message(LOG_WARNING,
                            "Invalid idle time setting. Only values greater than zero allowed; therefore setting idle timeout to %u seconds.",
                            MAX_IDLE_TIME);
                config.idletimeout = MAX_IDLE_TIME;
        }

        init_stats();

        /*
         * If ANONYMOUS is turned on, make sure that Content-Length is
         * in the list of allowed headers, since it is required in a
         * HTTP/1.0 request. Also add the Content-Type header since it goes
         * hand in hand with Content-Length.
         *     - rjkaes
         */
        if (is_anonymous_enabled()) {
                anonymous_insert("Content-Length");
                anonymous_insert("Content-Type");
        }

        if (godaemon == TRUE)
                makedaemon();

        if (config.pidpath) {
                if (pidfile_create(config.pidpath) < 0) {
                        fprintf(stderr, "%s: Could not create PID file.\n",
                                argv[0]);
                        exit(EX_OSERR);
                }
        }

        if (set_signal_handler(SIGPIPE, SIG_IGN) == SIG_ERR) {
                fprintf(stderr, "%s: Could not set the \"SIGPIPE\" signal.\n",
                        argv[0]);
                exit(EX_OSERR);
        }
#ifdef FILTER_ENABLE
        if (config.filter)
                filter_init();
#endif                          /* FILTER_ENABLE */

        /*
         * Start listening on the selected port.
         */
        if (child_listening_sock(config.port) < 0) {
                fprintf(stderr, "%s: Could not create listening socket.\n",
                        argv[0]);
                exit(EX_OSERR);
        }

        /*
         * Switch to a different user.
         */
        if (geteuid() == 0) {
                if (config.group && strlen(config.group) > 0) {
			int gid = get_id(config.group);
			if (gid < 0) {
				thisgroup = getgrnam(config.group);
				if (!thisgroup) {
					fprintf(stderr,
						"%s: Unable to find "
						"group \"%s\".\n",
						argv[0], config.group);
					exit(EX_NOUSER);
				}
				gid = thisgroup->gr_gid;
			}
                        if (setgid(gid) < 0) {
                                fprintf(stderr,
                                        "%s: Unable to change to "
					"group \"%s\".\n",
                                        argv[0], config.group);
                                exit(EX_CANTCREAT);
                        }
                        log_message(LOG_INFO, "Now running as group \"%s\".",
                                    config.group);
                }
                if (config.user && strlen(config.user) > 0) {
			int uid = get_id(config.user);
			if (uid < 0) {
				thisuser = getpwnam(config.user);
				if (!thisuser) {
					fprintf(stderr,
						"%s: Unable to find "
						"user \"%s\".",
						argv[0], config.user);
					exit(EX_NOUSER);
				}
				uid = thisuser->pw_uid;
			}
                        if (setuid(uid) < 0) {
                                fprintf(stderr,
                                        "%s: Unable to change to user \"%s\".",
                                        argv[0], config.user);
                                exit(EX_CANTCREAT);
                        }
                        log_message(LOG_INFO, "Now running as user \"%s\".",
                                    config.user);
                }
        } else {
                log_message(LOG_WARNING,
                            "Not running as root, so not changing UID/GID.");
        }

        if (child_pool_create() < 0) {
                fprintf(stderr, "%s: Could not create the pool of children.",
                        argv[0]);
                exit(EX_SOFTWARE);
        }

        /*
         * These signals are only for the parent process.
         */
        log_message(LOG_INFO, "Setting the various signals.");
        if (set_signal_handler(SIGCHLD, takesig) == SIG_ERR) {
                fprintf(stderr, "%s: Could not set the \"SIGCHLD\" signal.\n",
                        argv[0]);
                exit(EX_OSERR);
        }
        if (set_signal_handler(SIGTERM, takesig) == SIG_ERR) {
                fprintf(stderr, "%s: Could not set the \"SIGTERM\" signal.\n",
                        argv[0]);
                exit(EX_OSERR);
        }
        if (set_signal_handler(SIGHUP, takesig) == SIG_ERR) {
                fprintf(stderr, "%s: Could not set the \"SIGHUP\" signal.\n",
                        argv[0]);
                exit(EX_OSERR);
        }

        /*
         * Start the main loop.
         */
        log_message(LOG_INFO, "Starting main loop. Accepting connections.");

        child_main_loop();

        log_message(LOG_INFO, "Shutting down.");

        child_kill_children();
        child_close_sock();

        /*
         * Remove the PID file.
         */
        if (unlink(config.pidpath) < 0) {
                log_message(LOG_WARNING,
                            "Could not remove PID file \"%s\": %s.",
                            config.pidpath, strerror(errno));
        }
#ifdef FILTER_ENABLE
        if (config.filter)
                filter_destroy();
#endif                          /* FILTER_ENABLE */

        if (config.syslog)
                closelog();
        else
                close_log_file();

        exit(EX_OK);
}