/* Server for the Midnight Commander Virtual File System.
   
   Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
   2004, 2005, 2006, 2007 Free Software Foundation, Inc.

   Written by: 
      Miguel de Icaza, 1995, 1997, 
      Andrej Borsenkow 1996.
   
   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.

   TODO:
   opendir instead of keeping its table of file handles could return
   the pointer and expect the client to send a proper value back each
   time :-)

   We should use syslog to register login/logout.
   
    */

/* {{{ Includes and global variables */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#    include <unistd.h>
#endif
#include <string.h>
#ifdef HAVE_LIMITS_H
#    include <limits.h>
#endif
#ifndef NGROUPS_MAX
#    include <sys/param.h>
#    ifdef NGROUPS
#        define NGROUPS_MAX NGROUPS
#    endif
#endif
#ifdef HAVE_GRP_H
#    include <grp.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <errno.h>
#include <signal.h>
#ifdef HAVE_GETOPT_H
#    include <getopt.h>
#endif

/* Network include files */
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_PMAP_SET
#    include <rpc/rpc.h>
#    include <rpc/pmap_prot.h>
#    ifdef HAVE_RPC_PMAP_CLNT_H
#        include <rpc/pmap_clnt.h>
#    endif
#endif

#if defined(HAVE_PAM)
#  if !defined(HAVE_SECURITY_PAM_MISC_H)
#    undef HAVE_PAM
#  endif
#endif

/* Authentication include files */
#include <pwd.h>
#ifdef HAVE_PAM
#    include <security/pam_misc.h>
#    ifndef PAM_ESTABLISH_CRED
#        define PAM_ESTABLISH_CRED PAM_CRED_ESTABLISH
#    endif
#else
#endif				/* !HAVE_PAM */

#ifdef HAVE_CRYPT_H
#    include <crypt.h>
#endif				/* !HAVE_CRYPT_H */

#ifdef HAVE_SHADOW_H
#    include <shadow.h>
#else
#    ifdef HAVE_SHADOW_SHADOW_H
#        include <shadow/shadow.h>
#    endif
#endif

/*
 * GNU gettext defines printf to libintl_printf on platforms that lack
 * a native printf(3) capable of all POSIX features.
 */
#undef ENABLE_NLS
#include "../src/global.h"

#include "../src/tty.h"		/* enable/disable interrupt key */
#include "utilvfs.h"
#include "vfs.h"
#include "mcfs.h"
#include "mcfsutil.h"
#include "tcputil.h"

#ifndef INADDR_NONE
#  define INADDR_NONE (0xffffffffU)
#endif

/* replacement for g_free() from glib */
#undef g_free
#define g_free(x) do {if (x) free (x);} while (0)

/* We don't care about SIGPIPE */
int got_sigpipe = 0;

/* The socket from which we accept commands */
int msock;

/* Requested version number from client */
static int clnt_version;

/* If non zero, we accept further commands */
int logged_in = 0;

/* Home directory */
char * __restrict mcs_home_dir = NULL;

char *up_dir = NULL;

/* Were we started from inetd? */
int inetd_started = 0;

/* Are we running as a daemon? */
int isDaemon = 0;

/* guess */
int verbose = 0;

/* ftp auth */
int ftp = 0;

/* port number in which we listen to connections,
 * if zero, we try to contact the portmapper to get a port, and
 * if it's not possible, then we use a hardcoded value
 */
int portnum = 0;

/* if the server will use rcmd based authentication (hosts.equiv .rhosts) */
int r_auth = 0;

#define OPENDIR_HANDLES 8

#define DO_QUIT_VOID() \
do { \
  quit_server = 1; \
  return_code = 1; \
  return; \
} while (0)

/* Only used by get_port_number */
#define DO_QUIT_NONVOID(a) \
do { \
  quit_server = 1; \
  return_code = 1; \
  return (a); \
} while (0)

char buffer[4096];
int debug = 1;
static int quit_server;
static int return_code;

/* }}} */

/* {{{ Misc routines */

static void
send_status (int status, int errno_number)
{
    rpc_send (msock, RPC_INT, status, RPC_INT, errno_number, RPC_END);
    errno = 0;
}

/* }}} */

/* {{{ File with handle operations */

static void
do_open (void)
{
    int handle, flags, mode;
    char *arg;

    rpc_get (msock, RPC_STRING, &arg, RPC_INT, &flags, RPC_INT, &mode,
	     RPC_END);

    handle = open (arg, flags, mode);
    send_status (handle, errno);
    g_free (arg);
}

static void
do_read (void)
{
    int handle, count, n;
    void *data;

    rpc_get (msock, RPC_INT, &handle, RPC_INT, &count, RPC_END);
    data = malloc (count);
    if (!data) {
	send_status (-1, ENOMEM);
	return;
    }
    if (verbose)
	printf ("count=%d\n", count);
    n = read (handle, data, count);
    if (verbose)
	printf ("result=%d\n", n);
    if (n < 0) {
	send_status (-1, errno);
	return;
    }
    send_status (n, 0);
    rpc_send (msock, RPC_BLOCK, n, data, RPC_END);

    g_free (data);
}

static void
do_write (void)
{
    int handle, count, status, written = 0;
    char buf[8192];

    rpc_get (msock, RPC_INT, &handle, RPC_INT, &count, RPC_END);
    status = 0;
    while (count) {
	int nbytes = count > 8192 ? 8192 : count;

	rpc_get (msock, RPC_BLOCK, nbytes, buf, RPC_END);
	status = write (handle, buf, nbytes);
	if (status < 0) {
	    send_status (status, errno);
	    return;
	}
	/* FIXED: amount written must be returned to caller */
	written += status;
	if (status < nbytes) {
	    send_status (written, errno);
	    return;
	}
	count -= nbytes;
    }
    send_status (written, errno);
}

static void
do_lseek (void)
{
    int handle, offset, whence, status;

    rpc_get (msock, RPC_INT, &handle, RPC_INT, &offset, RPC_INT, &whence,
	     RPC_END);
    status = lseek (handle, offset, whence);
    send_status (status, errno);
}

static void
do_close (void)
{
    int handle, status;

    rpc_get (msock, RPC_INT, &handle, RPC_END);
    status = close (handle);
    send_status (status, errno);
}

/* Stat family routines */

static void
send_time (int sock, time_t sendtime)
{
    if (clnt_version == 1) {
	char *ct;
	int month;

	ct = ctime (&sendtime);
	ct[3] = ct[10] = ct[13] = ct[16] = ct[19] = 0;

	/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
	if (ct[4] == 'J') {
	    if (ct[5] == 'a') {
		month = 0;
	    } else
		month = (ct[6] == 'n') ? 5 : 6;
	} else if (ct[4] == 'F') {
	    month = 1;
	} else if (ct[4] == 'M') {
	    month = (ct[6] == 'r') ? 2 : 5;
	} else if (ct[4] == 'A') {
	    month = (ct[5] == 'p') ? 3 : 7;
	} else if (ct[4] == 'S') {
	    month = 8;
	} else if (ct[4] == 'O') {
	    month = 9;
	} else if (ct[4] == 'N') {
	    month = 10;
	} else
	    month = 11;
	rpc_send (sock, RPC_INT, atoi (&ct[17]), /* sec */
		  RPC_INT, atoi (&ct[14]),	  /* min */
		  RPC_INT, atoi (&ct[11]),	  /* hour */
		  RPC_INT, atoi (&ct[8]),	  /* mday */
		  RPC_INT, atoi (&ct[20]),	  /* year */
		  RPC_INT, month,                 /* month */
		  RPC_END);
    } else {
	long ltime = (long) sendtime;
	char buf[BUF_SMALL];

	snprintf (buf, sizeof (buf), "%lx", ltime);
	rpc_send (sock, RPC_STRING, buf, RPC_END);
    }
}

static void
send_stat_info (struct stat *st)
{
    long mylong;
    int blocks =
#ifdef HAVE_STRUCT_STAT_ST_BLOCKS
	st->st_blocks;
#else
	st->st_size / 1024;
#endif

#ifdef HAVE_STRUCT_STAT_ST_RDEV
    mylong = st->st_rdev;
#else
    mylong = 0;
#endif
    rpc_send (msock, RPC_INT, (long) mylong, RPC_INT, (long) st->st_ino,
	      RPC_INT, (long) st->st_mode, RPC_INT, (long) st->st_nlink,
	      RPC_INT, (long) st->st_uid, RPC_INT, (long) st->st_gid,
	      RPC_INT, (long) st->st_size, RPC_INT, (long) blocks,
	      RPC_END);
    send_time (msock, st->st_atime);
    send_time (msock, st->st_mtime);
    send_time (msock, st->st_ctime);
}

static void
do_lstat (void)
{
    struct stat st;
    char *file;
    int n;

    rpc_get (msock, RPC_STRING, &file, RPC_END);
    n = lstat (file, &st);
    send_status (n, errno);
    if (n >= 0)
	send_stat_info (&st);
    g_free (file);
}

static void
do_fstat (void)
{
    int handle;
    int n;
    struct stat st;

    rpc_get (msock, RPC_INT, &handle, RPC_END);
    n = fstat (handle, &st);
    send_status (n, errno);
    if (n < 0)
	return;

    send_stat_info (&st);
}

static void
do_stat (void)
{
    struct stat st;
    int n;
    char *file;

    rpc_get (msock, RPC_STRING, &file, RPC_END);

    n = stat (file, &st);
    send_status (n, errno);
    if (n >= 0)
	send_stat_info (&st);
    g_free (file);
}

/* }}} */

/* {{{ Directory lookup operations */

static struct {
    int used;
    DIR *dirs[OPENDIR_HANDLES];
    char *names[OPENDIR_HANDLES];
} mcfs_DIR;

static void
close_handle (int handle)
{
    if (mcfs_DIR.used > 0)
	mcfs_DIR.used--;
    if (mcfs_DIR.dirs[handle])
	closedir (mcfs_DIR.dirs[handle]);
    g_free (mcfs_DIR.names[handle]);
    mcfs_DIR.dirs[handle] = 0;
    mcfs_DIR.names[handle] = 0;
}

static void
do_opendir (void)
{
    int handle, i;
    char *arg;
    DIR *p;

    rpc_get (msock, RPC_STRING, &arg, RPC_END);

    if (mcfs_DIR.used == OPENDIR_HANDLES) {
	send_status (-1, ENFILE);	/* Error */
	g_free (arg);
	return;
    }

    handle = -1;
    for (i = 0; i < OPENDIR_HANDLES; i++) {
	if (mcfs_DIR.dirs[i] == 0) {
	    handle = i;
	    break;
	}
    }

    if (handle == -1) {
	send_status (-1, EMFILE);
	g_free (arg);
	if (!inetd_started)
	    fprintf (stderr,
		     "OOPS! you have found a bug in mc - do_opendir()!\n");
	return;
    }

    if (verbose)
	printf ("handle=%d\n", handle);
    p = opendir (arg);
    if (p) {
	mcfs_DIR.dirs[handle] = p;
	mcfs_DIR.names[handle] = arg;
	mcfs_DIR.used++;

	/* Because 0 is an error value */
	rpc_send (msock, RPC_INT, handle + 1, RPC_INT, 0, RPC_END);

    } else {
	send_status (-1, errno);
	g_free (arg);
    }
}

/* Sends the complete directory listing, as well as the stat information */
static void
do_readdir (void)
{
    struct dirent *dirent;
    struct stat st;
    int handle, n;

    rpc_get (msock, RPC_INT, &handle, RPC_END);

    if (!handle) {
	rpc_send (msock, RPC_INT, 0, RPC_END);
	return;
    }

    /* We incremented it in opendir */
    handle--;

    while ((dirent = readdir (mcfs_DIR.dirs[handle]))) {
	int fname_len;
	char *fname;
	int length = NLENGTH (dirent);

	rpc_send (msock, RPC_INT, length, RPC_END);
	rpc_send (msock, RPC_BLOCK, length, dirent->d_name, RPC_END);
	fname_len =
	    strlen (mcfs_DIR.names[handle]) + strlen (dirent->d_name) + 2;
	fname = malloc (fname_len);
	snprintf (fname, fname_len, "%s/%s", mcfs_DIR.names[handle],
		  dirent->d_name);
	n = lstat (fname, &st);
	g_free (fname);
	send_status (n, errno);
	if (n >= 0)
	    send_stat_info (&st);
    }
    rpc_send (msock, RPC_INT, 0, RPC_END);
}

static void
do_closedir (void)
{
    int handle;

    rpc_get (msock, RPC_INT, &handle, RPC_END);
    close_handle (handle - 1);
}

/* }}} */

/* {{{ Operations with one and two file name argument */

static void
do_chdir (void)
{
    char *file;
    int status;

    rpc_get (msock, RPC_STRING, &file, RPC_END);

    status = chdir (file);
    send_status (status, errno);
    g_free (file);
}

static void
do_rmdir (void)
{
    char *file;
    int status;

    rpc_get (msock, RPC_STRING, &file, RPC_END);

    status = rmdir (file);
    send_status (status, errno);
    g_free (file);
}

static void
do_mkdir (void)
{
    char *file;
    int mode, status;

    rpc_get (msock, RPC_STRING, &file, RPC_INT, &mode, RPC_END);

    status = mkdir (file, mode);
    send_status (status, errno);
    g_free (file);
}

static void
do_mknod (void)
{
    char *file;
    int mode, dev, status;

    rpc_get (msock, RPC_STRING, &file, RPC_INT, &mode, RPC_INT, &dev,
	     RPC_END);

    status = mknod (file, mode, dev);
    send_status (status, errno);
    g_free (file);
}

static void
do_readlink (void)
{
    char link_buffer[2048];
    char *file;
    int n;

    rpc_get (msock, RPC_STRING, &file, RPC_END);
    errno = 0;
    n = readlink (file, link_buffer, 2048 - 1);
    send_status (n, errno);
    if (n >= 0) {
	buffer[n] = 0;
	rpc_send (msock, RPC_STRING, link_buffer, RPC_END);
    }
    g_free (file);
}

static void
do_unlink (void)
{
    char *file;
    int status;

    rpc_get (msock, RPC_STRING, &file, RPC_END);
    status = unlink (file);
    send_status (status, errno);
    g_free (file);
}

static void
do_rename (void)
{
    char *f1, *f2;
    int status;

    rpc_get (msock, RPC_STRING, &f1, RPC_STRING, &f2, RPC_END);
    status = rename (f1, f2);
    send_status (status, errno);
    g_free (f1);
    g_free (f2);
}

static void
do_symlink (void)
{
    char *f1, *f2;
    int status;

    rpc_get (msock, RPC_STRING, &f1, RPC_STRING, &f2, RPC_END);
    status = symlink (f1, f2);
    send_status (status, errno);
    g_free (f1);
    g_free (f2);
}

static void
do_link (void)
{
    char *f1, *f2;
    int status;

    rpc_get (msock, RPC_STRING, &f1, RPC_STRING, &f2, RPC_END);
    status = link (f1, f2);
    send_status (status, errno);
    g_free (f1);
    g_free (f2);
}

/* {{{ Misc commands */

static void
do_gethome (void)
{
    rpc_send (msock, RPC_STRING, (mcs_home_dir) ? mcs_home_dir : "/", RPC_END);
}

static void
do_getupdir (void)
{
    rpc_send (msock, RPC_STRING, (up_dir) ? up_dir : "/", RPC_END);
}

static void
do_chmod (void)
{
    char *file;
    int mode, status;

    rpc_get (msock, RPC_STRING, &file, RPC_INT, &mode, RPC_END);
    status = chmod (file, mode);
    send_status (status, errno);
    g_free (file);
}

static void
do_chown (void)
{
    char *file;
    int owner, group, status;

    rpc_get (msock, RPC_STRING, &file, RPC_INT, &owner, RPC_INT, &group,
	     RPC_END);
    status = chown (file, owner, group);
    send_status (status, errno);
    g_free (file);
}

static void
do_utime (void)
{
    char *file;
    int status;
    long atime;
    long mtime;
    char *as;
    char *ms;
    struct utimbuf times;

    rpc_get (msock, RPC_STRING, &file, RPC_STRING, &as, RPC_STRING, &ms,
	     RPC_END);
    sscanf (as, "%lx", &atime);
    sscanf (ms, "%lx", &mtime);
    if (verbose)
	printf ("Got a = %s, m = %s, comp a = %ld, m = %ld\n", as, ms,
		atime, mtime);
    g_free (as);
    g_free (ms);
    times.actime = (time_t) atime;
    times.modtime = (time_t) mtime;
    status = utime (file, &times);
    send_status (status, errno);
    g_free (file);
}

static void
do_quit (void)
{
    quit_server = 1;
}

#ifdef HAVE_PAM

struct user_pass {
    const char *username;
    const char *password;
};

static int
mc_pam_conversation (int messages, const struct pam_message **msg,
		     struct pam_response **resp, void *appdata_ptr)
{
    struct pam_response *r;
    struct user_pass *up = appdata_ptr;
    int status;

    r = (struct pam_response *) malloc (sizeof (struct pam_response) *
					messages);
    if (!r)
	return PAM_CONV_ERR;
    *resp = r;

    for (status = PAM_SUCCESS; messages--; msg++, r++) {
	switch ((*msg)->msg_style) {

	case PAM_PROMPT_ECHO_ON:
	    r->resp = strdup (up->username);
	    r->resp_retcode = PAM_SUCCESS;
	    break;

	case PAM_PROMPT_ECHO_OFF:
	    r->resp = strdup (up->password);
	    r->resp_retcode = PAM_SUCCESS;
	    break;

	case PAM_ERROR_MSG:
	    r->resp = NULL;
	    r->resp_retcode = PAM_SUCCESS;
	    break;

	case PAM_TEXT_INFO:
	    r->resp = NULL;
	    r->resp_retcode = PAM_SUCCESS;
	    break;
	}
    }
    return status;
}

static struct pam_conv conv = { &mc_pam_conversation, NULL };


/* Return 0 if authentication failed, 1 otherwise */
static int
mc_pam_auth (const char *username, const char *password)
{
    pam_handle_t *pamh;
    struct user_pass up;
    int status;

    up.username = username;
    up.password = password;
    conv.appdata_ptr = &up;

    if ((status =
	 pam_start ("mcserv", username, &conv, &pamh)) != PAM_SUCCESS)
	goto failed_pam;
    if ((status = pam_authenticate (pamh, 0)) != PAM_SUCCESS)
	goto failed_pam;
    if ((status = pam_acct_mgmt (pamh, 0)) != PAM_SUCCESS)
	goto failed_pam;
    if ((status = pam_setcred (pamh, PAM_ESTABLISH_CRED)) != PAM_SUCCESS)
	goto failed_pam;
    pam_end (pamh, status);
    return 0;

  failed_pam:
    pam_end (pamh, status);
    return 1;
}

#else				/* !HAVE_PAM */

/* Keep reading until we find a \n */
static int
next_line (int socket)
{
    char c;

    while (1) {
	if (read (socket, &c, 1) <= 0)
	    return 0;
	if (c == '\n')
	    return 1;
    }
}

static int
ftp_answer (int sock, const char *text)
{
    char answer[4];

    next_line (sock);
    socket_read_block (sock, answer, 3);
    answer[3] = 0;
    if (strcmp (answer, text) == 0)
	return 1;
    return 0;
}

static int
send_string (int sock, const char *string)
{
    return socket_write_block (sock, string, strlen (string));
}

static int
do_ftp_auth (const char *username, const char *password)
{
    struct sockaddr_in local_address;
    unsigned long inaddr;
    int my_socket;
    char answer[4];

    memset ((char *) &local_address, 0, sizeof (local_address));

    local_address.sin_family = AF_INET;
    /* FIXME: extract the ftp port with the proper function */
    local_address.sin_port = htons (21);

    /*  Convert localhost to usable format */
    if ((inaddr = inet_addr ("127.0.0.1")) != INADDR_NONE)
	memcpy ((char *) &local_address.sin_addr, (char *) &inaddr,
		sizeof (inaddr));

    if ((my_socket = socket (AF_INET, SOCK_STREAM, 0)) < 0) {
	if (!isDaemon)
	    fprintf (stderr, "do_auth: can't create socket\n");
	return 0;
    }
    if (connect
	(my_socket, (struct sockaddr *) &local_address,
	 sizeof (local_address)) < 0) {
	fprintf (stderr,
		 "do_auth: can't connect to ftp daemon for authentication\n");
	close (my_socket);
	return 0;
    }
    send_string (my_socket, "user ");
    send_string (my_socket, username);
    send_string (my_socket, "\r\n");
    if (!ftp_answer (my_socket, "331")) {
	send_string (my_socket, "quit\r\n");
	close (my_socket);
	return 0;
    }
    next_line (my_socket);	/* Eat all the line */
    send_string (my_socket, "pass ");
    send_string (my_socket, password);
    send_string (my_socket, "\r\n");
    socket_read_block (my_socket, answer, 3);
    answer[3] = 0;
    send_string (my_socket, "\r\n");
    send_string (my_socket, "quit\r\n");
    close (my_socket);
    if (strcmp (answer, "230") == 0)
	return 1;
    return 0;
}

#ifdef HAVE_CRYPT
static int
do_classic_auth (const char *username, const char *password)
{
    int ret = 0;
    const char *encr_pwd = NULL;
    struct passwd *pw;
#ifdef HAVE_SHADOW
    struct spwd *spw;
#endif

    if ((pw = getpwnam (username)) == 0)
	return 0;

#ifdef HAVE_SHADOW
    setspent ();

    /* Password expiration is not checked! */
    if ((spw = getspnam (username)) == NULL)
	encr_pwd = "*";
    else
	encr_pwd = spw->sp_pwdp;

    endspent ();
#else
    encr_pwd = pw->pw_passwd;
#endif

    if (strcmp (crypt (password, encr_pwd), encr_pwd) == 0)
	ret = 1;

    endpwent ();
    return ret;
}
#endif				/* HAVE_CRYPT */
#endif				/* !HAVE_PAM */

/* Try to authenticate the user based on:
   - PAM if the system has it, else it checks:
   - pwdauth if the system supports it.
   - conventional auth (check salt on /etc/passwd, crypt, and compare
   - try to contact the local ftp server and login (if -f flag used)
*/
static int
do_auth (const char *username, const char *password)
{
    int auth = 0;
    struct passwd *this;

    if (strcmp (username, "anonymous") == 0)
	username = "ftp";

#ifdef HAVE_PAM
    if (mc_pam_auth (username, password) == 0)
	auth = 1;
#else				/* if there is no pam */
#ifdef HAVE_PWDAUTH
    if (pwdauth (username, password) == 0)
	auth = 1;
    else
#endif
#ifdef HAVE_CRYPT
    if (do_classic_auth (username, password))
	auth = 1;
    else
#endif
    if (ftp)
	auth = do_ftp_auth (username, password);
#endif				/* not pam */

    if (!auth)
	return 0;

    this = getpwnam (username);
    if (this == 0)
	return 0;

    if (chdir (this->pw_dir) == -1)
	return 0;

    if (this->pw_dir[strlen (this->pw_dir) - 1] == '/')
	mcs_home_dir = strdup (this->pw_dir);
    else {
    	char *new_home_dir = malloc (strlen (this->pw_dir) + 2);
	if (new_home_dir) {
	    strcpy (new_home_dir, this->pw_dir);
	    strcat (new_home_dir, "/");
	    mcs_home_dir = new_home_dir;
	} else
	    mcs_home_dir = "/";
    }


    if (setgid (this->pw_gid) == -1)
	return 0;

#ifdef HAVE_INITGROUPS
#ifdef NGROUPS_MAX
    if (NGROUPS_MAX > 1 && initgroups (this->pw_name, this->pw_gid))
	return 0;
#endif
#endif

#if defined (HAVE_SETUID)
    if (setuid (this->pw_uid))
	return 0;
#elif defined (HAVE_SETREUID)
    if (setreuid (this->pw_uid, this->pw_uid))
	return 0;
#endif

    /* If the setuid call failed, then deny access */
    /* This should fix the problem on those machines with strange setups */
    if (getuid () != this->pw_uid)
	return 0;

    if (strcmp (username, "ftp") == 0)
	chroot (this->pw_dir);

    endpwent ();
    return auth;
}

#if 0
static int
do_rauth (int socket)
{
    struct sockaddr_in from;
    struct hostent *hp;

    if (getpeername (0, (struct sockaddr *) &from, &fromlen) < 0)
	return 0;
    from.sin_port = ntohs ((unsigned short) from.sin_port);

    /* Strange, this should not happend */
    if (from.sin_family != AF_INET)
	return 0;

    hp = gethostbyaddr ((char *) &fromp.sin_addr, sizeof (struct in_addr),
			fromp.sin_family);

}
#endif

static int
do_rauth (int m_sock _ATTRIBUTE_UNUSED_)
{
    return 0;
}

static void
login_reply (int reply_logged_in)
{
    rpc_send (msock, RPC_INT, reply_logged_in ? MC_LOGINOK : MC_INVALID_PASS,
	      RPC_END);
}

/* FIXME: Implement the anonymous login */
static void
do_login (void)
{
    char *username;
    char *password;
    int result;

    rpc_get (msock, RPC_LIMITED_STRING, &up_dir, RPC_LIMITED_STRING,
	     &username, RPC_END);
    if (verbose)
	printf ("username: %s\n", username);

    if (r_auth) {
	logged_in = do_rauth (msock);
	if (logged_in) {
	    login_reply (logged_in);
	    return;
	}
    }
    rpc_send (msock, RPC_INT, MC_NEED_PASSWORD, RPC_END);
    rpc_get (msock, RPC_INT, &result, RPC_END);
    if (result == MC_QUIT)
	DO_QUIT_VOID ();
    if (result != MC_PASS) {
	if (verbose)
	    printf ("do_login: Unknown response: %d\n", result);
	DO_QUIT_VOID ();
    }
    rpc_get (msock, RPC_LIMITED_STRING, &password, RPC_END);
    logged_in = do_auth (username, password);
    endpwent ();
    login_reply (logged_in);
}

/* }}} */

/* {{{ Server and dispatching functions */

/* This structure must be kept in synch with mcfs.h enums */

static const struct _command {
    const char *command;
    void (*callback) (void);
} commands[] = {
    {
    "open", do_open}, {
    "close", do_close}, {
    "read", do_read}, {
    "write", do_write}, {
    "opendir", do_opendir}, {
    "readdir", do_readdir}, {
    "closedir", do_closedir}, {
    "stat ", do_stat}, {
    "lstat ", do_lstat}, {
    "fstat", do_fstat}, {
    "chmod", do_chmod}, {
    "chown", do_chown}, {
    "readlink ", do_readlink}, {
    "unlink", do_unlink}, {
    "rename", do_rename}, {
    "chdir ", do_chdir}, {
    "lseek", do_lseek}, {
    "rmdir", do_rmdir}, {
    "symlink", do_symlink}, {
    "mknod", do_mknod}, {
    "mkdir", do_mkdir}, {
    "link", do_link}, {
    "gethome", do_gethome}, {
    "getupdir", do_getupdir}, {
    "login", do_login}, {
    "quit", do_quit}, {
"utime", do_utime}};

static int ncommands = sizeof (commands) / sizeof (struct _command);

static void
exec_command (int command)
{
    if (command < 0 || command >= ncommands
	|| commands[command].command == 0) {
	fprintf (stderr, "Got unknown command: %d\n", command);
	DO_QUIT_VOID ();
    }
    if (verbose)
	printf ("Command: %s\n", commands[command].command);
    (*commands[command].callback) ();
}

static void
check_version (void)
{
    int version;

    rpc_get (msock, RPC_INT, &version, RPC_END);
    if (version >= 1 && version <= RPC_PROGVER)
	rpc_send (msock, RPC_INT, MC_VERSION_OK, RPC_END);
    else
	rpc_send (msock, RPC_INT, MC_VERSION_MISMATCH, RPC_END);

    clnt_version = version;
}

/* This routine is called by rpc_get/rpc_send when the connection is closed */
void
tcp_invalidate_socket (int sock _ATTRIBUTE_UNUSED_)
{
    if (verbose)
	printf ("Connection closed\n");
    DO_QUIT_VOID ();
}

static void
server (int sock)
{
    int command;

    msock = sock;
    quit_server = 0;

    check_version ();
    do {
	if (rpc_get (sock, RPC_INT, &command, RPC_END)
	    && (logged_in || command == MC_LOGIN))
	    exec_command (command);
    } while (!quit_server);
}

/* }}} */

/* {{{ Net support code */

static const char *
get_client (int client_portnum)
{
    int sock, newsocket;
    unsigned int clilen;
    struct sockaddr_in client_address, server_address;
    int yes = 1;

    if ((sock = socket (AF_INET, SOCK_STREAM, 0)) < 0)
	return "Cannot create socket";

    /* Use this to debug: */
    if (setsockopt
	(sock, SOL_SOCKET, SO_REUSEADDR, (char *) &yes, sizeof (yes)) < 0)
	return "setsockopt failed";

    memset ((char *) &server_address, 0, sizeof (server_address));
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = htonl (INADDR_ANY);
    server_address.sin_port = htons (client_portnum);

    if (bind
	(sock, (struct sockaddr *) &server_address,
	 sizeof (server_address)) < 0)
	return "Cannot bind";

    listen (sock, 5);

    for (;;) {
	int child;

	clilen = sizeof (client_address);
	newsocket =
	    accept (sock, (struct sockaddr *) &client_address, &clilen);

	if (isDaemon && (child = fork ())) {
	    int status;

	    close (newsocket);
	    waitpid (child, &status, 0);
	    continue;
	}

	if (isDaemon && fork ())
	    exit (0);

	server (newsocket);
	close (newsocket);
	return 0;
    }
}

#ifdef HAVE_PMAP_SET
static void
signal_int_handler (int sig)
{
    (void) sig;

    pmap_unset (RPC_PROGNUM, RPC_PROGVER);
}
#endif

#ifndef IPPORT_RESERVED
#define IPPORT_RESERVED 1024
#endif

static int
get_port_number (void)
{
    int port = 0;

#ifdef HAVE_RRESVPORT
    int start_port = IPPORT_RESERVED;

    port = rresvport (&start_port);
    if (port == -1) {
	if (geteuid () == 0) {
	    fprintf (stderr,
		     "Cannot bind the server on a reserved port\n");
	    DO_QUIT_NONVOID (-1);
	}
	port = 0;
    }
#endif
    if (port)
	return port;

    port = mcserver_port;

    return port;
}

static void 
register_port (int register_portnum, int abort_if_fail)
{
#ifdef HAVE_PMAP_SET
    /* Register our service with the portmapper */
    /* protocol: pmap_set (prognum, versnum, protocol, portp) */

    if (pmap_set (RPC_PROGNUM, RPC_PROGVER, IPPROTO_TCP, register_portnum))
	signal (SIGINT, signal_int_handler);
    else {
	fprintf (stderr, "Cannot register service with portmapper\n");
	if (abort_if_fail)
	    exit (1);
    }
#else
    if (abort_if_fail) {
	fprintf (stderr,
		 "This system lacks port registration, try using the -p\n"
		 "flag to force installation at a given port");
    }
#endif
}

/* }}} */

int 
main (int argc, char *argv[])
{
    const char *result;
    int c;

    while ((c = getopt (argc, argv, "fdiqp:v")) != -1) {
	switch (c) {
	case 'd':
	    isDaemon = 1;
	    verbose = 0;
	    break;

	case 'v':
	    verbose = 1;
	    break;

	case 'f':
	    ftp = 1;
	    break;

	case 'q':
	    verbose = 0;
	    break;

	case 'p':
	    portnum = atoi (optarg);
	    break;

	case 'i':
	    inetd_started = 1;
	    break;

	case 'r':
	    r_auth = 1;
	    break;

	default:
	    fprintf (stderr,
		     "Usage is: mcserv [options] [-p portnum]\n\n"
		     "options are:\n" "-d  become a daemon (sets -q)\n"
		     "-q  quiet mode\n"
		     /*    "-r  use rhost based authentication\n" */
#ifndef HAVE_PAM
		     "-f  force ftp authentication\n"
#endif
		     "-v  verbose mode\n"
		     "-p  to specify a port number to listen\n");
	    exit (0);

	}
    }

    if (isDaemon && fork ())
	exit (0);

    if (portnum == 0)
	portnum = get_port_number ();

    if (portnum != -1) {
	register_port (portnum, 0);
	if (verbose)
	    printf ("Using port %d\n", portnum);
	if ((result = get_client (portnum)))
	    perror (result);
#ifdef HAVE_PMAP_SET
	if (!isDaemon)
	    pmap_unset (RPC_PROGNUM, RPC_PROGVER);
#endif
    }
    exit (return_code);
}

void  _ATTRIBUTE_NORETURN_
vfs_die (const char *m)
{
    fputs (m, stderr);
    exit (1);
};
