/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Entrypoint and utility functions
   Copyright (C) Matthew Chapman 1999-2003

   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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <stdarg.h>		/* va_list va_start va_end */
#include <unistd.h>		/* read close getuid getgid getpid getppid gethostname */
#include <fcntl.h>		/* open */
#include <pwd.h>		/* getpwuid */
#include <termios.h>		/* tcgetattr tcsetattr */
#include <sys/stat.h>		/* stat */
#include <sys/time.h>		/* gettimeofday */
#include <sys/times.h>		/* times */
#include <ctype.h>		/* toupper */
#include <errno.h>
#include "rdesktop.h"

#ifdef EGD_SOCKET
#include <sys/socket.h>		/* socket connect */
#include <sys/un.h>		/* sockaddr_un */
#endif

#ifdef WITH_OPENSSL
#include <openssl/md5.h>
#else
#include "crypto/md5.h"
#endif

char g_title[64] = "";
char g_username[64];
char hostname[16];
char keymapname[16];
int keylayout = 0x409;		/* Defaults to US keyboard layout */

int g_width = 800;		/* width is special: If 0, the
				   geometry will be fetched from
				   _NET_WORKAREA. If negative,
				   absolute value specifies the
				   percent of the whole screen. */
int g_height = 600;
int tcp_port_rdp = TCP_PORT_RDP;
int g_server_bpp = 8;
int g_win_button_size = 0;	/* If zero, disable single app mode */
BOOL g_bitmap_compression = True;
BOOL g_sendmotion = True;
BOOL g_orders = True;
BOOL g_encryption = True;
BOOL packet_encryption = True;
BOOL g_desktop_save = True;
BOOL g_fullscreen = False;
BOOL g_grab_keyboard = True;
BOOL g_hide_decorations = False;
BOOL g_use_rdp5 = True;
BOOL g_console_session = False;
BOOL g_numlock_sync = False;
extern BOOL g_owncolmap;
extern BOOL g_ownbackstore;
extern uint32 g_embed_wnd;
uint32 g_rdp5_performanceflags = RDP5_NO_WALLPAPER | RDP5_NO_FULLWINDOWDRAG | RDP5_NO_MENUANIMATIONS;

#ifdef WITH_RDPSND
BOOL g_rdpsnd = False;
#endif

extern RDPDR_DEVICE g_rdpdr_device[];
extern uint32 g_num_devices;
extern char * g_rdpdr_clientname;

#ifdef RDP2VNC
extern int rfb_port;
extern int defer_time;
void
rdp2vnc_connect(char *server, uint32 flags, char *domain, char *password,
		char *shell, char *directory);
#endif
/* Display usage information */
static void
usage(char *program)
{
	fprintf(stderr, "rdesktop: A Remote Desktop Protocol client.\n");
	fprintf(stderr, "Version " VERSION ". Copyright (C) 1999-2003 Matt Chapman.\n");
	fprintf(stderr, "See http://www.rdesktop.org/ for more information.\n\n");

	fprintf(stderr, "Usage: %s [options] server[:port]\n", program);
#ifdef RDP2VNC
	fprintf(stderr, "   -V: vnc port\n");
	fprintf(stderr, "   -Q: defer time (ms)\n");
#endif
	fprintf(stderr, "   -u: user name\n");
	fprintf(stderr, "   -d: domain\n");
	fprintf(stderr, "   -s: shell\n");
	fprintf(stderr, "   -c: working directory\n");
	fprintf(stderr, "   -p: password (- to prompt)\n");
	fprintf(stderr, "   -n: client hostname\n");
	fprintf(stderr, "   -k: keyboard layout on server (en-us, de, sv, etc.)\n");
	fprintf(stderr, "   -g: desktop geometry (WxH)\n");
	fprintf(stderr, "   -f: full-screen mode\n");
	fprintf(stderr, "   -b: force bitmap updates\n");
	fprintf(stderr, "   -B: use BackingStore of X-server (if available)\n");
	fprintf(stderr, "   -e: disable encryption (French TS)\n");
	fprintf(stderr, "   -E: disable encryption from client to server\n");
	fprintf(stderr, "   -m: do not send motion events\n");
	fprintf(stderr, "   -C: use private colour map\n");
	fprintf(stderr, "   -D: hide window manager decorations\n");
	fprintf(stderr, "   -K: keep window manager key bindings\n");
	fprintf(stderr, "   -S: caption button size (single application mode)\n");
	fprintf(stderr, "   -T: window title\n");
	fprintf(stderr, "   -N: enable numlock syncronization\n");
	fprintf(stderr, "   -X: embed into another window with a given id.\n");
	fprintf(stderr, "   -a: connection colour depth\n");
	fprintf(stderr, "   -x: RDP5 experience (m[odem 28.8], b[roadband], l[an] or hex number)\n");
	fprintf(stderr, "   -r: enable specified device redirection (this flag can be repeated)\n");
	fprintf(stderr,
		"         '-r comport:COM1=/dev/ttyS0': enable serial redirection of /dev/ttyS0 to COM1\n");
	fprintf(stderr, "             or      COM1=/dev/ttyS0,COM2=/dev/ttyS1\n");
	fprintf(stderr,
		"         '-r disk:A=/mnt/floppy': enable redirection of /mnt/floppy to A:\n");
	fprintf(stderr, "             or   A=/mnt/floppy,D=/mnt/cdrom'\n");
	fprintf(stderr, "         '-r clientname=<client name>': Set the client name displayed\n");
	fprintf(stderr, "             for redirected disks\n");
	fprintf(stderr,
		"         '-r lptport:LPT1=/dev/lp0': enable parallel redirection of /dev/lp0 to LPT1\n");
	fprintf(stderr, "             or      LPT1=/dev/lp0,LPT2=/dev/lp1\n");
	fprintf(stderr, "         '-r printer:mydeskjet': enable printer redirection\n");
	fprintf(stderr,
		"             or      mydeskjet=\"HP LaserJet IIIP\" to enter server driver as well\n");
	fprintf(stderr, "         '-r sound:[local|off|remote]': enable sound redirection\n");
	fprintf(stderr, "                     remote would leave sound on server\n");
	fprintf(stderr, "   -0: attach to console\n");
	fprintf(stderr, "   -4: use RDP version 4\n");
	fprintf(stderr, "   -5: use RDP version 5 (default)\n");
}

static BOOL
read_password(char *password, int size)
{
	struct termios tios;
	BOOL ret = False;
	int istty = 0;
	char *p;

	if (tcgetattr(STDIN_FILENO, &tios) == 0)
	{
		fprintf(stderr, "Password: ");
		tios.c_lflag &= ~ECHO;
		tcsetattr(STDIN_FILENO, TCSANOW, &tios);
		istty = 1;
	}

	if (fgets(password, size, stdin) != NULL)
	{
		ret = True;

		/* strip final newline */
		p = strchr(password, '\n');
		if (p != NULL)
			*p = 0;
	}

	if (istty)
	{
		tios.c_lflag |= ECHO;
		tcsetattr(STDIN_FILENO, TCSANOW, &tios);
		fprintf(stderr, "\n");
	}

	return ret;
}

static void
parse_server_and_port(char *server)
{
	char *p;
#ifdef IPv6
	int addr_colons;
#endif

#ifdef IPv6
	p = server;
	addr_colons = 0;
	while (*p)
		if (*p++ == ':')
			addr_colons++;
	if (addr_colons >= 2)
	{
		/* numeric IPv6 style address format - [1:2:3::4]:port */
		p = strchr(server, ']');
		if (*server == '[' && p != NULL)
		{
			if (*(p + 1) == ':' && *(p + 2) != '\0')
				tcp_port_rdp = strtol(p + 2, NULL, 10);
			/* remove the port number and brackets from the address */
			*p = '\0';
			strncpy(server, server + 1, strlen(server));
		}
	}
	else
	{
		/* dns name or IPv4 style address format - server.example.com:port or 1.2.3.4:port */
		p = strchr(server, ':');
		if (p != NULL)
		{
			tcp_port_rdp = strtol(p + 1, NULL, 10);
			*p = 0;
		}
	}
#else /* no IPv6 support */
	p = strchr(server, ':');
	if (p != NULL)
	{
		tcp_port_rdp = strtol(p + 1, NULL, 10);
		*p = 0;
	}
#endif /* IPv6 */

}

/* Client program */
int
main(int argc, char *argv[])
{
	char server[64];
	char fullhostname[64];
	char domain[16];
	char password[64];
	char shell[128];
	char directory[32];
	BOOL prompt_password, rdp_retval = False;
	struct passwd *pw;
	uint32 flags;
	char *p;
	int c;

	int username_option = 0;

	flags = RDP_LOGON_NORMAL;
	prompt_password = False;
	domain[0] = password[0] = shell[0] = directory[0] = 0;
	strcpy(keymapname, "en-us");
	g_embed_wnd = 0;

	g_num_devices = 0;

#ifdef RDP2VNC
#define VNCOPT "V:Q:"
#else
#define VNCOPT
#endif

	while ((c = getopt(argc, argv, VNCOPT "u:d:s:c:p:n:k:g:fbBeEmCDKS:T:NX:a:x:r:045h?")) != -1)
	{
		switch (c)
		{
#ifdef RDP2VNC
			case 'V':
				rfb_port = strtol(optarg, NULL, 10);
				if (rfb_port < 100)
					rfb_port += 5900;
				break;

			case 'Q':
				defer_time = strtol(optarg, NULL, 10);
				if (defer_time < 0)
					defer_time = 0;
				break;
#endif

			case 'u':
				STRNCPY(g_username, optarg, sizeof(g_username));
				username_option = 1;
				break;

			case 'd':
				STRNCPY(domain, optarg, sizeof(domain));
				break;

			case 's':
				STRNCPY(shell, optarg, sizeof(shell));
				break;

			case 'c':
				STRNCPY(directory, optarg, sizeof(directory));
				break;

			case 'p':
				if ((optarg[0] == '-') && (optarg[1] == 0))
				{
					prompt_password = True;
					break;
				}

				STRNCPY(password, optarg, sizeof(password));
				flags |= RDP_LOGON_AUTO;

				/* try to overwrite argument so it won't appear in ps */
				p = optarg;
				while (*p)
					*(p++) = 'X';
				break;

			case 'n':
				STRNCPY(hostname, optarg, sizeof(hostname));
				break;

			case 'k':
				STRNCPY(keymapname, optarg, sizeof(keymapname));
				break;

			case 'g':
				g_fullscreen = False;
				if (!strcmp(optarg, "workarea"))
				{
					g_width = g_height = 0;
					break;
				}

				g_width = strtol(optarg, &p, 10);
				if (g_width <= 0)
				{
					error("invalid geometry\n");
					return 1;
				}

				if (*p == 'x')
					g_height = strtol(p + 1, NULL, 10);

				if (g_height <= 0)
				{
					error("invalid geometry\n");
					return 1;
				}

				if (*p == '%')
					g_width = -g_width;

				break;

			case 'f':
				g_fullscreen = True;
				break;

			case 'b':
				g_orders = False;
				break;

			case 'B':
				g_ownbackstore = False;
				break;

			case 'e':
				g_encryption = False;
				break;
			case 'E':
				packet_encryption = False;
				break;
			case 'm':
				g_sendmotion = False;
				break;

			case 'C':
				g_owncolmap = True;
				break;

			case 'D':
				g_hide_decorations = True;
				break;

			case 'K':
				g_grab_keyboard = False;
				break;

			case 'S':
				if (!strcmp(optarg, "standard"))
				{
					g_win_button_size = 18;
					break;
				}

				g_win_button_size = strtol(optarg, &p, 10);

				if (*p)
				{
					error("invalid button size\n");
					return 1;
				}

				break;

			case 'T':
				STRNCPY(g_title, optarg, sizeof(g_title));
				break;

			case 'N':
				g_numlock_sync = True;
				break;

			case 'X':
				g_embed_wnd = strtol(optarg, NULL, 10);
				break;
				
			case 'a':
				g_server_bpp = strtol(optarg, NULL, 10);
				if (g_server_bpp != 8 && g_server_bpp != 16 && g_server_bpp != 15
				    && g_server_bpp != 24)
				{
					error("invalid server bpp\n");
					return 1;
				}
				break;

			case 'x':
				
				if (strncmp("modem", optarg, 1) == 0)
				{
					g_rdp5_performanceflags = RDP5_NO_WALLPAPER | RDP5_NO_FULLWINDOWDRAG | RDP5_NO_MENUANIMATIONS | RDP5_NO_THEMING;
				}
				else if (strncmp("broadband", optarg, 1) == 0)
				{
					g_rdp5_performanceflags = RDP5_NO_WALLPAPER;
				}
				else if (strncmp("lan", optarg, 1) == 0)
				{
					g_rdp5_performanceflags = RDP5_DISABLE_NOTHING;
				}
				else
				{
					g_rdp5_performanceflags = strtol(optarg, NULL, 16);
				}
				break;
				
			case 'r':

				if (strncmp("sound", optarg, 5) == 0)
				{
					optarg += 5;

					if (*optarg == ':')
					{
						*optarg++;
						while ((p = next_arg(optarg, ',')))
						{
							if (strncmp("remote", optarg, 6) == 0)
								flags |= RDP_LOGON_LEAVE_AUDIO;

							if (strncmp("local", optarg, 5) == 0)
#ifdef WITH_RDPSND
								g_rdpsnd = True;
#else
								warning("Not compiled with sound support");
#endif

							if (strncmp("off", optarg, 3) == 0)
								g_rdpsnd = False;

							optarg = p;
						}
					}
					else
					{
#ifdef WITH_RDPSND
						g_rdpsnd = True;
#else
						warning("Not compiled with sound support");
#endif
					}
				}
				else if (strncmp("disk", optarg, 4) == 0)
				{
					/* -r disk:h:=/mnt/floppy */
					disk_enum_devices(&g_num_devices, optarg + 4);
				}
				else if (strncmp("comport", optarg, 7) == 0)
				{
					serial_enum_devices(&g_num_devices, optarg + 7);
				}
				else if (strncmp("lptport", optarg, 7) == 0)
				{
					parallel_enum_devices(&g_num_devices, optarg + 7);
				}
				else if (strncmp("printer", optarg, 7) == 0)
				{
					printer_enum_devices(&g_num_devices, optarg + 7);
				}
				else if (strncmp("clientname", optarg, 7) == 0)
				{
					g_rdpdr_clientname = xmalloc(strlen(optarg+11)+1);
					strcpy(g_rdpdr_clientname, optarg + 11);
				}
				else
				{
					warning("Unknown -r argument\n\n\tPossible arguments are: comport, disk, lptport, printer, sound\n");
				}
				break;

			case '0':
				g_console_session = True;
				break;

			case '4':
				g_use_rdp5 = False;
				break;

			case '5':
				g_use_rdp5 = True;
				break;

			case 'h':
			case '?':
			default:
				usage(argv[0]);
				return 1;
		}
	}

	if (argc - optind != 1)
	{
		usage(argv[0]);
		return 1;
	}

	STRNCPY(server, argv[optind], sizeof(server));
	parse_server_and_port(server);

	if (!username_option)
	{
		pw = getpwuid(getuid());
		if ((pw == NULL) || (pw->pw_name == NULL))
		{
			error("could not determine username, use -u\n");
			return 1;
		}

		STRNCPY(g_username, pw->pw_name, sizeof(g_username));
	}

	if (hostname[0] == 0)
	{
		if (gethostname(fullhostname, sizeof(fullhostname)) == -1)
		{
			error("could not determine local hostname, use -n\n");
			return 1;
		}

		p = strchr(fullhostname, '.');
		if (p != NULL)
			*p = 0;

		STRNCPY(hostname, fullhostname, sizeof(hostname));
	}

	if (prompt_password && read_password(password, sizeof(password)))
		flags |= RDP_LOGON_AUTO;

	if (g_title[0] == 0)
	{
		strcpy(g_title, "rdesktop - ");
		strncat(g_title, server, sizeof(g_title) - sizeof("rdesktop - "));
	}

#ifdef RDP2VNC
	rdp2vnc_connect(server, flags, domain, password, shell, directory);
	return 0;
#else

	if (!ui_init())
		return 1;

#ifdef WITH_RDPSND
	if (g_rdpsnd)
		rdpsnd_init();
#endif
	rdpdr_init();

	if (!rdp_connect(server, flags, domain, password, shell, directory))
		return 1;

	/* By setting encryption to False here, we have an encrypted login 
	   packet but unencrypted transfer of other packets */
	if (!packet_encryption)
		g_encryption = False;


	DEBUG(("Connection successful.\n"));
	memset(password, 0, sizeof(password));

	if (ui_create_window())
	{
		rdp_retval = rdp_main_loop();
		ui_destroy_window();
	}

	DEBUG(("Disconnecting...\n"));
	rdp_disconnect();
	ui_deinit();

	if (True == rdp_retval)
		return 0;
	else
		return 2;

#endif

}

#ifdef EGD_SOCKET
/* Read 32 random bytes from PRNGD or EGD socket (based on OpenSSL RAND_egd) */
static BOOL
generate_random_egd(uint8 * buf)
{
	struct sockaddr_un addr;
	BOOL ret = False;
	int fd;

	fd = socket(AF_UNIX, SOCK_STREAM, 0);
	if (fd == -1)
		return False;

	addr.sun_family = AF_UNIX;
	memcpy(addr.sun_path, EGD_SOCKET, sizeof(EGD_SOCKET));
	if (connect(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1)
		goto err;

	/* PRNGD and EGD use a simple communications protocol */
	buf[0] = 1;		/* Non-blocking (similar to /dev/urandom) */
	buf[1] = 32;		/* Number of requested random bytes */
	if (write(fd, buf, 2) != 2)
		goto err;

	if ((read(fd, buf, 1) != 1) || (buf[0] == 0))	/* Available? */
		goto err;

	if (read(fd, buf, 32) != 32)
		goto err;

	ret = True;

      err:
	close(fd);
	return ret;
}
#endif

/* Generate a 32-byte random for the secure transport code. */
void
generate_random(uint8 * random)
{
	struct stat st;
	struct tms tmsbuf;
	MD5_CTX md5;
	uint32 *r;
	int fd, n;

	/* If we have a kernel random device, try that first */
	if (((fd = open("/dev/urandom", O_RDONLY)) != -1)
	    || ((fd = open("/dev/random", O_RDONLY)) != -1))
	{
		n = read(fd, random, 32);
		close(fd);
		if (n == 32)
			return;
	}

#ifdef EGD_SOCKET
	/* As a second preference use an EGD */
	if (generate_random_egd(random))
		return;
#endif

	/* Otherwise use whatever entropy we can gather - ideas welcome. */
	r = (uint32 *) random;
	r[0] = (getpid()) | (getppid() << 16);
	r[1] = (getuid()) | (getgid() << 16);
	r[2] = times(&tmsbuf);	/* system uptime (clocks) */
	gettimeofday((struct timeval *) &r[3], NULL);	/* sec and usec */
	stat("/tmp", &st);
	r[5] = st.st_atime;
	r[6] = st.st_mtime;
	r[7] = st.st_ctime;

	/* Hash both halves with MD5 to obscure possible patterns */
	MD5_Init(&md5);
	MD5_Update(&md5, random, 16);
	MD5_Final(random, &md5);
	MD5_Update(&md5, random + 16, 16);
	MD5_Final(random + 16, &md5);
}

/* malloc; exit if out of memory */
void *
xmalloc(int size)
{
	void *mem = malloc(size);
	if (mem == NULL)
	{
		error("xmalloc %d\n", size);
		exit(1);
	}
	return mem;
}

/* realloc; exit if out of memory */
void *
xrealloc(void *oldmem, int size)
{
	void *mem = realloc(oldmem, size);
	if (mem == NULL)
	{
		error("xrealloc %d\n", size);
		exit(1);
	}
	return mem;
}

/* free */
void
xfree(void *mem)
{
	free(mem);
}

/* report an error */
void
error(char *format, ...)
{
	va_list ap;

	fprintf(stderr, "ERROR: ");

	va_start(ap, format);
	vfprintf(stderr, format, ap);
	va_end(ap);
}

/* report a warning */
void
warning(char *format, ...)
{
	va_list ap;

	fprintf(stderr, "WARNING: ");

	va_start(ap, format);
	vfprintf(stderr, format, ap);
	va_end(ap);
}

/* report an unimplemented protocol feature */
void
unimpl(char *format, ...)
{
	va_list ap;

	fprintf(stderr, "NOT IMPLEMENTED: ");

	va_start(ap, format);
	vfprintf(stderr, format, ap);
	va_end(ap);
}

/* produce a hex dump */
void
hexdump(unsigned char *p, unsigned int len)
{
	unsigned char *line = p;
	int i, thisline, offset = 0;

	while (offset < len)
	{
		printf("%04x ", offset);
		thisline = len - offset;
		if (thisline > 16)
			thisline = 16;

		for (i = 0; i < thisline; i++)
			printf("%02x ", line[i]);

		for (; i < 16; i++)
			printf("   ");

		for (i = 0; i < thisline; i++)
			printf("%c", (line[i] >= 0x20 && line[i] < 0x7f) ? line[i] : '.');

		printf("\n");
		offset += thisline;
		line += thisline;
	}
}

/*
  input: src is the string we look in for needle.
  	 Needle may be escaped by a backslash, in
	 that case we ignore that particular needle.
  return value: returns next src pointer, for
  	succesive executions, like in a while loop
	if retval is 0, then there are no more args.
  pitfalls:
  	src is modified. 0x00 chars are inserted to
	terminate strings.
	return val, points on the next val chr after ins
	0x00

	example usage:
	while( (pos = next_arg( optarg, ',')) ){
		printf("%s\n",optarg);
		optarg=pos;
	}

*/
char *
next_arg(char *src, char needle)
{
	char *nextval;
	char *p;
	char *mvp = 0;

	/* EOS */
	if (*src == (char) 0x00)
		return 0;

	p = src;
	/*  skip escaped needles */
	while ((nextval = strchr(p, needle)))
	{
		mvp = nextval - 1;
		/* found backslashed needle */
		if (*mvp == '\\' && (mvp > src))
		{
			/* move string one to the left */
			while (*(mvp + 1) != (char) 0x00)
			{
				*mvp = *(mvp + 1);
				*mvp++;
			}
			*mvp = (char) 0x00;
			p = nextval;
		}
		else
		{
			p = nextval + 1;
			break;
		}

	}

	/* more args available */
	if (nextval)
	{
		*nextval = (char) 0x00;
		return ++nextval;
	}

	/* no more args after this, jump to EOS */
	nextval = src + strlen(src);
	return nextval;
}


void
toupper_str(char *p)
{
	while (*p)
	{
		if ((*p >= 'a') && (*p <= 'z'))
			*p = toupper((int) *p);
		p++;
	}
}


/* not all clibs got ltoa */
#define LTOA_BUFSIZE (sizeof(long) * 8 + 1)

char *
l_to_a(long N, int base)
{
	static char ret[LTOA_BUFSIZE];

	char *head = ret, buf[LTOA_BUFSIZE], *tail = buf + sizeof(buf);

	register int divrem;

	if (base < 36 || 2 > base)
		base = 10;

	if (N < 0)
	{
		*head++ = '-';
		N = -N;
	}

	tail = buf + sizeof(buf);
	*--tail = 0;

	do
	{
		divrem = N % base;
		*--tail = (divrem <= 9) ? divrem + '0' : divrem + 'a' - 10;
		N /= base;
	}
	while (N);

	strcpy(head, tail);
	return ret;
}


int
load_licence(unsigned char **data)
{
	char *home, *path;
	struct stat st;
	int fd, length;

	home = getenv("HOME");
	if (home == NULL)
		return -1;

	path = (char *) xmalloc(strlen(home) + strlen(hostname) + sizeof("/.rdesktop/licence."));
	sprintf(path, "%s/.rdesktop/licence.%s", home, hostname);

	fd = open(path, O_RDONLY);
	if (fd == -1)
		return -1;

	if (fstat(fd, &st))
		return -1;

	*data = (uint8 *) xmalloc(st.st_size);
	length = read(fd, *data, st.st_size);
	close(fd);
	xfree(path);
	return length;
}

void
save_licence(unsigned char *data, int length)
{
	char *home, *path, *tmppath;
	int fd;

	home = getenv("HOME");
	if (home == NULL)
		return;

	path = (char *) xmalloc(strlen(home) + strlen(hostname) + sizeof("/.rdesktop/licence."));

	sprintf(path, "%s/.rdesktop", home);
	if ((mkdir(path, 0700) == -1) && errno != EEXIST)
	{
		perror(path);
		return;
	}

	/* write licence to licence.hostname.new, then atomically rename to licence.hostname */

	sprintf(path, "%s/.rdesktop/licence.%s", home, hostname);
	tmppath = (char *) xmalloc(strlen(path) + sizeof(".new"));
	strcpy(tmppath, path);
	strcat(tmppath, ".new");

	fd = open(tmppath, O_WRONLY | O_CREAT | O_TRUNC, 0600);
	if (fd == -1)
	{
		perror(tmppath);
		return;
	}

	if (write(fd, data, length) != length)
	{
		perror(tmppath);
		unlink(tmppath);
	}
	else if (rename(tmppath, path) == -1)
	{
		perror(path);
		unlink(tmppath);
	}

	close(fd);
	xfree(tmppath);
	xfree(path);
}