/* service-thread.c -- skeleton for Cyrus service; calls the real main
 *
 * Copyright (c) 1994-2008 Carnegie Mellon University.  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. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Carnegie Mellon University
 *      Center for Technology Transfer and Enterprise Creation
 *      4615 Forbes Avenue
 *      Suite 302
 *      Pittsburgh, PA  15213
 *      (412) 268-7393, fax: (412) 268-7395
 *      innovation@andrew.cmu.edu
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * $Id: service-thread.c,v 1.21 2008/03/24 17:47:41 murch Exp $
 */

#include <config.h>

#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <syslog.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdlib.h>
#include <sysexits.h>
#include <string.h>

#include "service.h"
#include "libconfig.h"
#include "xmalloc.h"

extern int optind;
extern char *optarg;

/* number of times this service has been used */
static int use_count = 0;
static int verbose = 0;

void notify_master(int fd, int msg)
{
    struct notify_message notifymsg;
    if (verbose) syslog(LOG_DEBUG, "telling master %x", msg);
    notifymsg.message = msg;
    notifymsg.service_pid = getpid();
    if (write(fd, &notifymsg, sizeof(notifymsg)) != sizeof(notifymsg)) {
	syslog(LOG_ERR, "unable to tell master %x: %m", msg);
    }
}

#ifdef HAVE_LIBWRAP
#include <tcpd.h>

int allow_severity = LOG_DEBUG;
int deny_severity = LOG_ERR;

static void libwrap_init(struct request_info *r, char *service)
{
    request_init(r, RQ_DAEMON, service, 0);
}

static int libwrap_ask(struct request_info *r, int fd)
{
    int a;
    struct sockaddr_storage sin;
    socklen_t len = sizeof(sin);
    
    /* XXX: old FreeBSD didn't fill sockaddr correctly against AF_UNIX */
    sin.ss_family = AF_UNIX;

    /* is this a connection from the local host? */
    if (getpeername(fd, (struct sockaddr *) &sin, &len) == 0) {
	if (((struct sockaddr *)&sin)->sa_family == AF_UNIX) {
	    return 1;
	}
    }
    
    /* i hope using the sock_* functions are legal; it certainly makes
       this code very easy! */
    request_set(r, RQ_FILE, fd, 0);
    sock_host(r);

    a = hosts_access(r);
    if (!a) {
	syslog(deny_severity, "refused connection from %s", eval_client(r));
    }

    return a;
}

#else
struct request_info { int x; };

static void libwrap_init(struct request_info *r __attribute__((unused)),
			 char *service __attribute__((unused)))
{

}

static int libwrap_ask(struct request_info *r __attribute__((unused)),
		       int fd __attribute__((unused)))
{
    return 1;
}

#endif

extern void cyrus_init(const char *, const char *, unsigned);

#define ARGV_GROW 10

int main(int argc, char **argv, char **envp)
{
    int fdflags;
    int fd;
    char *p = NULL, *service;
    struct request_info request;
    int opt;
    char *alt_config = NULL;
    int call_debugger = 0;
    int newargc = 0;
    char **newargv = (char **) xmalloc(ARGV_GROW * sizeof(char *));

    opterr = 0; /* disable error reporting,
		   since we don't know about service-specific options */

    newargv[newargc++] = argv[0];

    while ((opt = getopt(argc, argv, "C:D")) != EOF) {
	switch (opt) {
	case 'C': /* alt config file */
	    alt_config = optarg;
	    break;
	case 'D':
	    call_debugger = 1;
	    break;
	default:
	    if (!((newargc+1) % ARGV_GROW)) { /* time to alloc more */
		newargv = (char **) xrealloc(newargv, (newargc + ARGV_GROW) * 
					     sizeof(char *));
	    }
	    newargv[newargc++] = argv[optind-1];

	    /* option has an argument */
	    if (optind < argc && argv[optind][0] != '-')
		newargv[newargc++] = argv[optind++];

	    break;
	}
    }
    /* grab the remaining arguments */
    for (; optind < argc; optind++) {
	if (!(newargc % ARGV_GROW)) { /* time to alloc more */
	    newargv = (char **) xrealloc(newargv, (newargc + ARGV_GROW) * 
					 sizeof(char *));
	}
	newargv[newargc++] = argv[optind];
    }

    opterr = 1; /* enable error reporting */
    optind = 1; /* reset the option index for parsing by the service */

    p = getenv("CYRUS_VERBOSE");
    if (p) verbose = atoi(p) + 1;

    if (verbose > 30) {
	syslog(LOG_DEBUG, "waiting 15 seconds for debugger");
	sleep(15);
    }

    p = getenv("CYRUS_SERVICE");
    if (p == NULL) {
	syslog(LOG_ERR, "could not getenv(CYRUS_SERVICE); exiting");
	exit(EX_SOFTWARE);
    }
    service = xstrdup(p);

    cyrus_init(alt_config, service, 0);

    if (call_debugger) {
	char debugbuf[1024];
	int ret;
	const char *debugger = config_getstring(IMAPOPT_DEBUG_COMMAND);
	if (debugger) {
	    snprintf(debugbuf, sizeof(debugbuf), debugger, 
		     argv[0], getpid(), service);
	    syslog(LOG_DEBUG, "running external debugger: %s", debugbuf);
	    ret = system(debugbuf); /* run debugger */
	    syslog(LOG_DEBUG, "debugger returned exit status: %d", ret);
	}
    }
    syslog(LOG_DEBUG, "executed");

    /* set close on exec */
    fdflags = fcntl(LISTEN_FD, F_GETFD, 0);
    if (fdflags != -1) fdflags = fcntl(LISTEN_FD, F_SETFD, 
				       fdflags | FD_CLOEXEC);
    if (fdflags == -1) {
	syslog(LOG_ERR, "unable to set close on exec: %m");
	if (MESSAGE_MASTER_ON_EXIT) 
	    notify_master(STATUS_FD, MASTER_SERVICE_UNAVAILABLE);
	return 1;
    }
    fdflags = fcntl(STATUS_FD, F_GETFD, 0);
    if (fdflags != -1) fdflags = fcntl(STATUS_FD, F_SETFD, 
				       fdflags | FD_CLOEXEC);
    if (fdflags == -1) {
	syslog(LOG_ERR, "unable to set close on exec: %m");
	if (MESSAGE_MASTER_ON_EXIT) 
	    notify_master(STATUS_FD, MASTER_SERVICE_UNAVAILABLE);
	return 1;
    }

    if (service_init(newargc, newargv, envp) != 0) {
	if (MESSAGE_MASTER_ON_EXIT) 
	    notify_master(STATUS_FD, MASTER_SERVICE_UNAVAILABLE);
	return 1;
    }

    for (;;) {
	/* ok, listen to this socket until someone talks to us */
	fd = -1;
	while (fd < 0) { /* loop until we succeed */
	    fd = accept(LISTEN_FD, NULL, NULL);
	    if (fd < 0) {
		switch (errno) {
		case ENETDOWN:
#ifdef EPROTO
		case EPROTO:
#endif
		case ENOPROTOOPT:
		case EHOSTDOWN:
#ifdef ENONET
		case ENONET:
#endif
		case EHOSTUNREACH:
		case EOPNOTSUPP:
		case ENETUNREACH:
		case EAGAIN:
		case EINTR:
		case ECONNABORTED:
		    break;
		default:
		    syslog(LOG_ERR, "accept failed: %m");
		    if (MESSAGE_MASTER_ON_EXIT) 
			notify_master(STATUS_FD, MASTER_SERVICE_UNAVAILABLE);
		    service_abort(EX_OSERR);
		}
	    }
	}
	
	libwrap_init(&request, getenv("CYRUS_SERVICE"));

	if (!libwrap_ask(&request, fd)) {
	    /* connection denied! */
	    shutdown(fd, SHUT_RDWR);
	    close(fd);
	    continue;
	}
	
	syslog(LOG_DEBUG, "accepted connection");

	use_count++;
	notify_master(STATUS_FD, MASTER_SERVICE_CONNECTION_MULTI);
	if (service_main_fd(fd, newargc, newargv, envp) < 0) {
	    break;
	}
    }

    if (MESSAGE_MASTER_ON_EXIT) 
	notify_master(STATUS_FD, MASTER_SERVICE_UNAVAILABLE);
    service_abort(0);
    return 0;
}
