/*
 * Copyright (c) 2004, Nate Nielsen
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *     * Redistributions of source code must retain the above
 *       copyright notice, this list of conditions and the
 *       following disclaimer.
 *     * 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.
 *     * The names of contributors to this software may not be
 *       used to endorse or promote products derived from this
 *       software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
 * COPYRIGHT OWNER 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.
 *
 *
 * CONTRIBUTORS
 *  Nate Nielsen <nielsen@memberwebs.com>
 *  Yamamoto Takao <takao@oakat.org>
 */

#include <paths.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <err.h>
#include <pthread.h>
#include <syslog.h>

#include "usuals.h"
#include "compat.h"
#include "clamsmtpd.h"
#include "util.h"

/* -----------------------------------------------------------------------
 *  DIRECTIONS FOR ADDING A CONFIGURATION OPTION
 *
 * - Add field to clstate_t structure in clamsmtpd.h
 * - Add default and set in clstate_init (below)
 * - Add config keyword (below)
 * - Parsing of option in clstate_parse_config (below)
 * - Validation of option in clstate_validate (below)
 * - Document in the sample doc/clamsmtpd.conf
 * - Document in doc/clamsmtpd.conf.5
 */

/* -----------------------------------------------------------------------
 *  DEFAULT SETTINGS
 */

#define DEFAULT_SOCKET  "10025"
#define DEFAULT_PORT    10025
#define DEFAULT_CLAMAV  "/var/run/clamav/clamd"
#define DEFAULT_MAXTHREADS  64
#define DEFAULT_TIMEOUT	180
#define DEFAULT_HEADER  "X-AV-Checked: ClamAV using ClamSMTP"

/* -----------------------------------------------------------------------
 *  CONFIG KEYWORDS
 */

#define CFG_MAXTHREADS  "MaxConnections"
#define CFG_TIMEOUT     "TimeOut"
#define CFG_OUTADDR     "OutAddress"
#define CFG_LISTENADDR  "Listen"
#define CFG_CLAMADDR    "ClamAddress"
#define CFG_HEADER      "ScanHeader"
#define CFG_DIRECTORY   "TempDirectory"
#define CFG_BOUNCE      "Bounce"
#define CFG_QUARANTINE  "Quarantine"
#define CFG_DEBUGFILES  "DebugFiles"
#define CFG_TRANSPARENT "TransparentProxy"

/* The set of delimiters that can be present between config and value */
#define CFG_DELIMS      ": \t"

/* -----------------------------------------------------------------------
 *  CODE
 */

/* String to bool helper function */
static int strtob(const char* str)
{
    if(strcasecmp(str, "0") == 0 ||
       strcasecmp(str, "no") == 0 ||
       strcasecmp(str, "false") == 0 ||
       strcasecmp(str, "f") == 0 ||
       strcasecmp(str, "off") == 0)
        return 0;

    if(strcasecmp(str, "1") == 0 ||
       strcasecmp(str, "yes") == 0 ||
       strcasecmp(str, "true") == 0 ||
       strcasecmp(str, "t") == 0 ||
       strcasecmp(str, "on") == 0)
        return 1;

    return -1;
}

void clstate_init(clstate_t* state)
{
    ASSERT(state);
	memset(state, 0, sizeof(*state));

	/* Setup the defaults */
	state->debug_level = -1;
	state->max_threads = DEFAULT_MAXTHREADS;
	state->timeout.tv_sec = DEFAULT_TIMEOUT;
    state->clamname = DEFAULT_CLAMAV;
    state->listenname = DEFAULT_SOCKET;
    state->header = DEFAULT_HEADER;
    state->directory = _PATH_TMP;

    /* Create the main mutex and condition variable */
    if(pthread_mutexattr_init(&(state->_mtxattr)) != 0 ||
       pthread_mutexattr_settype(&(state->_mtxattr), MUTEX_TYPE) ||
       pthread_mutex_init(&(state->mutex), &(state->_mtxattr)) != 0)
        errx(1, "threading problem. can't create mutex or condition var");
}

int clstate_parse_config(clstate_t* state, const char* configfile)
{
    FILE* f = NULL;
    long len;
    int r;
    char* p;
    char* t;
    char* n;

    ASSERT(state);
    ASSERT(configfile);
    ASSERT(!state->_p);

    f = fopen(configfile, "r");
    if(f == NULL)
    {
        /* Soft errors when default config file and not found */
        if((errno == ENOENT || errno == ENOTDIR))
            return -1;
        else
            err(1, "couldn't open config file: %s", configfile);
    }

    if(fseek(f, 0, SEEK_END) == -1 || (len = ftell(f)) == -1 || fseek(f, 0, SEEK_SET) == -1)
        err(1, "couldn't seek config file: %s", configfile);

    if((state->_p = (char*)malloc(len + 2)) == NULL)
        errx(1, "out of memory");

    if(fread(state->_p, 1, len, f) != len)
        err(1, "couldn't read config file: %s", configfile);

    fclose(f);
    messagex(NULL, LOG_DEBUG, "opened config file: %s", configfile);

    /* Double null terminate the data */
    p = state->_p;
    p[len] = 0;
    p[len + 1] = 0;

    n = state->_p;

    /* Go through lines and process them */
    while((t = strchr(n, '\n')) != NULL)
    {
        *t = 0;
        p = n; /* Do this before cleaning below */
        n = t + 1;

        p = trim_space(p);

        /* Comments and empty lines */
        if(*p == 0 || *p == '#')
            continue;

        /* Save some code typing below */
        #define PARSE(o) \
            (r = check_first_word(p, (o), KL(o), CFG_DELIMS))
        #define VAL \
            (p + r)

        /*
         * Note that we don't validate here. If something's wrong
         * set it to an invalid value.
         */

        if(PARSE(CFG_MAXTHREADS))
        {
            state->max_threads = strtol(VAL, &t, 10);
            if(*t) /* parse failed */
                state->max_threads = -1;
        }

        else if(PARSE(CFG_TIMEOUT))
        {
            state->timeout.tv_sec = strtol(VAL, &t, 10);
            if(*t) /* parse failed */
                state->timeout.tv_sec = -1;
        }

        else if(PARSE(CFG_OUTADDR))
            state->outname = VAL;

        else if(PARSE(CFG_LISTENADDR))
            state->listenname = VAL;

        else if(PARSE(CFG_CLAMADDR))
            state->clamname = VAL;

        else if(PARSE(CFG_HEADER))
            state->header = VAL;

        else if(PARSE(CFG_DIRECTORY))
            state->directory = VAL;

        else if(PARSE(CFG_BOUNCE))
            state->bounce = strtob(VAL);

        else if(PARSE(CFG_QUARANTINE))
            state->quarantine = strtob(VAL);

        else if(PARSE(CFG_DEBUGFILES))
            state->debug_files = strtob(VAL);

        else if(PARSE(CFG_TRANSPARENT))
            state->transparent = strtob(VAL);

        /* Unrecognized option */
        else
            errx(2, "invalid config line: %s", p);

        messagex(NULL, LOG_DEBUG, "parsed line: %s", p);
    }

    return 0;
}

void clstate_validate(clstate_t* state)
{
    ASSERT(state);
    messagex(NULL, LOG_DEBUG, "validating configuration options");

    if(!(state->debug_level == -1 || state->debug_level <= LOG_DEBUG))
        errx(2, "invalid debug log level (must be between 1 and 4)");

    if(state->max_threads <= 1 || state->max_threads >= 1024)
        errx(2, "invalid setting: " CFG_MAXTHREADS " (must be between 1 and 1024)");

    if(state->timeout.tv_sec <= 0)
        errx(2, "invalid setting: " CFG_TIMEOUT);

    if(state->bounce == -1)
        errx(2, "invalid value for " CFG_BOUNCE);
    if(state->quarantine == -1)
        errx(2, "invalid value for " CFG_QUARANTINE);
    if(state->debug_files == -1)
        errx(2, "invalid value for " CFG_DEBUGFILES);

    /* This option has no default, but is required */
    if(state->outname == NULL && !state->transparent)
        errx(2, "no " CFG_OUTADDR " specified.");

    /* Parse all the addresses */
    if(state->outname != NULL)
    {
        if(state->transparent)
            warnx("the " CFG_OUTADDR " option will be ignored when " CFG_TRANSPARENT " is enabled");
        else
            if(sock_any_pton(state->outname, &(state->outaddr), SANY_OPT_DEFPORT(25)) == -1)
                errx(2, "invalid " CFG_OUTADDR " socket name or ip: %s", state->outname);
    }

    if(sock_any_pton(state->listenname, &(state->listenaddr), SANY_OPT_DEFANY | SANY_OPT_DEFPORT(DEFAULT_PORT)) == -1)
        errx(2, "invalid " CFG_LISTENADDR " socket name or ip: %s", state->listenname);
    if(sock_any_pton(state->clamname, &(state->clamaddr), SANY_OPT_DEFLOCAL) == -1)
        errx(2, "invalid " CFG_CLAMADDR " socket name: %s", state->clamname);

    if(strlen(state->directory) == 0)
        errx(2, "invalid setting: " CFG_DIRECTORY);

    if(state->header)
    {
        /*
         * This is for when it comes from the command-line.
         * Once command line args are phased out this can be removed
         */
        state->header = (const char*)trim_space((char*)state->header);

        if(strlen(state->header) == 0)
            state->header = NULL;
    }
}

void clstate_cleanup(clstate_t* state)
{
    /* Close the mutex */
    pthread_mutex_destroy(&(state->mutex));
    pthread_mutexattr_destroy(&(state->_mtxattr));

    if(state->_p)
        free(state->_p);

    memset(state, 0, sizeof(*state));
}