/******************************************************************************
    (c) 1999 P.J. Caulfield               patrick@tykepenguin.cix.co.uk
    
    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
    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.
 ******************************************************************************
*/
////
// dnetd.cc
// DECnet super-server
////

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <syslog.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <pwd.h>
#include <netdnet/dn.h>
#include <netdnet/dnetdb.h>

#ifndef SDF_WILD
#warning SDF_WILD not defined. This program may not work with your kernel
#define SDF_WILD 1
#endif

#define MAX_ARGS 256

void sigchild(int s);
void sigterm(int s);
int  open_server_socket(void);

extern void task_server(int, int, int);

// Global variables.
static int verbosity = 0;
static volatile int do_shutdown = 0;
static char binary_dir[PATH_MAX];

void usage(char *prog, FILE *f)
{
    fprintf(f,"\n%s options:\n", prog);
    fprintf(f," -v        Verbose messages\n");
    fprintf(f," -h        Show this help text\n");
    fprintf(f," -d        Debug - don't do initial fork\n");
    fprintf(f," -s        Don't run scripts in users' directories\n");
    fprintf(f," -l<type>  Logging type(s:syslog, e:stderr, m:mono)\n");
    fprintf(f," -p<dir>   Path to find daemon programs\n");
    fprintf(f," -V        Show version number\n\n");
}

// Run a pre-defined daemon
void exec_daemon(int sockfd, char *daemon_name)
{
    char *argv[MAX_ARGS];
    int   argc = 0;
    char *argp;
    int   err;
    int   i;
    char  name[PATH_MAX];
	    
    // Split the daemon command into a command and its args
    argp = strtok(daemon_name, " ");
    while (argp && argc < MAX_ARGS)
    {
	argv[argc++] = argp;
	argp = strtok(NULL, " ");
    }
    argv[argc] = NULL;

    // Point stderr to /dev/null just in case
    err = open("/dev/null", O_RDWR);


    // Make STDIN & STDOUT the DECnet socket.
    dup2(sockfd, 0);
    dup2(sockfd, 1);
    if (err != 2) dup2(err, 2);
    fcntl(0, F_SETFD, 0); // Don't close on exec
    fcntl(1, F_SETFD, 0);
    fcntl(2, F_SETFD, 0);

    // Close all the others. This next line is, of course, bollocks
    for (i=3; i<256; i++) close(i);

    // Look for the daemon in $(prefix) if the name is not absolute
    if (daemon_name[0] != '/')
    {
	if (strlen(binary_dir)+strlen(daemon_name)+1 > PATH_MAX)
	{
	    DNETLOG((LOG_ERR, "Can't exec daemon %s. Name too long ", daemon_name));
	    return;
	}
	strcpy(name, binary_dir);
	strcat(name, "/");
	strcat(name, daemon_name);
    }
    else
    {
	if (strlen(daemon_name) > PATH_MAX)
	{
	    DNETLOG((LOG_ERR, "Can't exec daemon %s. Name too long ", daemon_name));
	    return;
	}
	strcpy(name, daemon_name);
    }

    // Run it...
    execvp(name, argv);
    DNETLOG((LOG_ERR, "exec of daemon %s failed: %m", name));
}

// Code for MIRROR object
void mirror(int insock)
{
    char ibuf[4097];
    char condata[] = {0x00, 0x20}; // Actually 4096 as a LE word
    int readnum;

    dnet_accept(insock, 0, condata, 2);

    while ( (readnum=read(insock,ibuf,sizeof(ibuf))) > 0)
    {
	ibuf[0]=0x01;
	if (write(insock,ibuf,readnum) < 0)
	{
	    DNETLOG((LOG_WARNING, "mirror, write failed: %m\n"));
	    close(insock);
	    break;
	}
    }
    close(insock);
}


// Start here...
int main(int argc, char *argv[])
{
    pid_t              pid;
    char               opt;
    int                fd;
    struct sockaddr_dn sockaddr;
    struct stat        st;
    int		       debug=0;
    int                status;
    int                secure=0;
    int                len = sizeof(sockaddr);
    char               log_char = 'l'; // Default to syslog(3)
    char               condata[] = {0x00, 0x20}; // Actually 4096 as a LE word

    // make default binaries directory name
    strcpy(binary_dir, BINARY_PREFIX);
    strcat(binary_dir, "/sbin");
    
    // Deal with command-line arguments. Do these before the check for root
    // so we can check the version number and get help without being root.
    opterr = 0;
    optind = 0;
    while ((opt=getopt(argc,argv,"?vVhp:sdl:")) != EOF)
    {
	switch(opt) 
	{
	case 'h': 
	    usage(argv[0], stdout);
	    exit(0);

	case '?':
	    usage(argv[0], stderr);
	    exit(0);

	case 'v':
	    verbosity++;
	    break;

	case 'd':
	    debug++;
	    break;

	case 's':
	    secure++;
	    break;

	case 'V':
	    printf("\ntaskd from dnprogs version %s\n\n", VERSION);
	    exit(1);
	    break;
	    
	case 'p':
	    if (stat(optarg, &st) < 0)
	    {
		fprintf(stderr, "%s does not exist\n", optarg);
		exit(-1);
	    }
	    if (!S_ISDIR(st.st_mode))
	    {
		fprintf(stderr, "%s is not a directory\n", optarg);
		exit(-1);
	    }
	    strcpy(binary_dir, optarg);
	    break;
	    
	case 'l':
	    if (optarg[0] != 's' &&
		optarg[0] != 'm' &&
		optarg[0] != 'e')
	    {
		usage(argv[0], stderr);
		exit(2);
	    }
	    log_char = optarg[0];
	    break;
	}
    }

    // Initialise logging
    init_daemon_logging("dnetd", log_char);

    // Needed for dnetd on Eduardo's kernel to
    // be able to do MIRROR
    dnet_set_optdata(condata, sizeof(condata));
    
    fd = dnet_daemon(0, NULL, verbosity, debug?0:1);
    if (fd > -1)
    {
	char *daemon_name = dnet_daemon_name();
	struct   sockaddr_dn  sockaddr;
	int      er;
	unsigned int namlen = sizeof(sockaddr);

	// Should we execute an external daemon ?
        // The external daemon should dnet_accept() the socket
	if (daemon_name && strcmp(daemon_name, "internal"))
	{
	    if (verbosity >1)
		DNETLOG((LOG_INFO, "Starting daemon '%s'\n", daemon_name));
	    exec_daemon(fd, daemon_name);
	    return 0;
	}
	
	// Dispatch the object internally
	// If it's a named object then run a task script
	getsockname(fd, (struct sockaddr *)&sockaddr, &namlen);
	if (sockaddr.sdn_objnamel)
	{
	    task_server(fd, verbosity, secure);
	    return 0;
	}

	// Choose a numbered object
	switch (sockaddr.sdn_objnum)
	{
	case DNOBJECT_MIRROR:
	    if (verbosity >1)
		DNETLOG((LOG_INFO, "Doing mirror\n"));
	    mirror(fd);
	    break;

	default:
	    DNETLOG((LOG_ERR, "Don't know how to handle object %d\n",
		    sockaddr.sdn_objnum));
	    dnet_reject(fd, DNSTAT_OBJECT, NULL, 0);
	    break;
	}
    }
    return 0;
}