libtdevnc/x11vnc/avahi.c

/* -- avahi.c -- */

#include "x11vnc.h"
#include "connections.h"
#include "cleanup.h"

void avahi_initialise(void);
void avahi_advertise(const char *name, const char *host, const uint16_t port);
void avahi_reset(void);
void avahi_cleanup(void);

static pid_t avahi_pid = 0;

static void kill_avahi_pid(void) {
	if (avahi_pid != 0) {
		kill(avahi_pid, SIGTERM);
		avahi_pid = 0;
	}
}

static int try_avahi_helper(const char *name, const char *host, const uint16_t port) {
#if LIBVNCSERVER_HAVE_FORK
	char *cmd, *p, *path = getenv("PATH"), portstr[32];
	int i;

	if (!name || !host || !port) {}

	/* avahi-publish */
	if (no_external_cmds || !cmd_ok("zeroconf")) {
		return 0;
	}

	if (!path) {
		return 0;
	}

	path = strdup(path); 
	cmd = (char *) malloc(strlen(path) + 100);
	sprintf(portstr, "%d", (int) port);

	p = strtok(path, ":");
	while (p) {
		struct stat sbuf;

		sprintf(cmd, "%s/avahi-publish", p);
		if (stat(cmd, &sbuf) == 0) {
			break;
		}
		sprintf(cmd, "%s/dns-sd", p);
		if (stat(cmd, &sbuf) == 0) {
			break;
		}
		sprintf(cmd, "%s/mDNS", p);
		if (stat(cmd, &sbuf) == 0) {
			break;
		}
		cmd[0] = '\0';

		p = strtok(NULL, ":");
	}
	free(path);

	if (!strcmp(cmd, "")) {
		free(cmd);
		rfbLog("Could not find an external avahi/zeroconf helper program.\n");
		return 0;
	}

	avahi_pid = fork();

	if (avahi_pid < 0) {
		rfbLogPerror("fork");
		avahi_pid = 0;
		free(cmd);
		return 0;
	}

	if (avahi_pid != 0) {
		int status;

		usleep(500 * 1000);
		waitpid(avahi_pid, &status, WNOHANG); 
		if (kill(avahi_pid, 0) != 0) {
			waitpid(avahi_pid, &status, WNOHANG); 
			avahi_pid = 0;
			free(cmd);
			return 0;
		}
		if (! quiet) {
			rfbLog("%s helper pid is: %d\n", cmd, (int) avahi_pid);
		}
		free(cmd);
		return 1;
	}

	for (i=3; i<256; i++) {
		close(i);
	}

	if (strstr(cmd, "/avahi-publish")) {
		execlp(cmd, cmd, "-s", name, "_rfb._tcp", portstr, (char *) NULL);
	} else {
		execlp(cmd, cmd, "-R", name, "_rfb._tcp", ".", portstr, (char *) NULL);
	}
	exit(1);
#else
	if (!name || !host || !port) {}
	return 0;
#endif
}

#if !defined(LIBVNCSERVER_HAVE_AVAHI) || !defined(LIBVNCSERVER_HAVE_LIBPTHREAD)
void avahi_initialise(void) {
	rfbLog("avahi_initialise: no Avahi support at buildtime.\n");
}

void avahi_advertise(const char *name, const char *host, const uint16_t port) {
	if (!try_avahi_helper(name, host, port)) {
		rfbLog("avahi_advertise:  no Avahi support at buildtime.\n");
		avahi = 0;
	}
}

void avahi_reset(void) {
	kill_avahi_pid();
	rfbLog("avahi_reset: no Avahi support at buildtime.\n");
}

void avahi_cleanup(void) {
	kill_avahi_pid();
	rfbLog("avahi_cleanup: no Avahi support at buildtime.\n");
}
#else

#include <avahi-common/thread-watch.h>
#include <avahi-common/alternative.h>
#include <avahi-client/client.h>
#include <avahi-client/publish.h>

#include <avahi-common/malloc.h>
#include <avahi-common/error.h>


static AvahiThreadedPoll *_poll = NULL;
static AvahiClient *_client = NULL;
static AvahiEntryGroup *_group = NULL;

static int db = 0;

typedef struct {
	const char *name;
	const char *host;
	uint16_t port;
} avahi_service_t;

typedef struct {
	char *name;
	char *host;
	uint16_t port;
} avahi_reg_t;

#define NREG 16
static avahi_reg_t registered[NREG];

void avahi_initialise(void) {
	int ret;
	static int first = 1;

	if (getenv("AVAHI_DEBUG")) {
		db = 1;
	}
	if (first) {
		int i;
		for (i=0; i<NREG; i++) {
			registered[i].name = NULL;
			registered[i].host = NULL;
		}
		first = 0;
	}

if (db) fprintf(stderr, "in  avahi_initialise\n");
	if (_poll) {
if (db) fprintf(stderr, "    avahi_initialise: poll not null\n");
		return;
	}

	if (! (_poll = avahi_threaded_poll_new()) ) {
		rfbLog("warning: unable to open Avahi poll.\n");
		return;
	}

	_client = avahi_client_new(avahi_threaded_poll_get(_poll),
	    0, NULL, NULL, &ret);
	if (! _client) {
		rfbLog("warning: unable to open Avahi client: %s\n",
		    avahi_strerror(ret));

		avahi_threaded_poll_free(_poll);
		_poll = NULL;
		return;
	}

	if (avahi_threaded_poll_start(_poll) < 0) {
		rfbLog("warning: unable to start Avahi poll.\n");
		avahi_client_free(_client);
		_client = NULL;
		avahi_threaded_poll_free(_poll);
		_poll = NULL;
		return;
	}
if (db) fprintf(stderr, "out avahi_initialise\n");
}

static void _avahi_create_services(const char *name, const char *host,
    const uint16_t port);

static void _avahi_entry_group_callback(AvahiEntryGroup *g,
    AvahiEntryGroupState state, void *userdata) {
	char *new_name;
	avahi_service_t *svc = (avahi_service_t *)userdata;

if (db) fprintf(stderr, "in  _avahi_entry_group_callback %d 0x%p\n", state, svc);
	if (g != _group && _group != NULL) {
		rfbLog("avahi_entry_group_callback fatal error (group).\n");
		clean_up_exit(1);
	}
	if (userdata == NULL) {
		rfbLog("avahi_entry_group_callback fatal error (userdata).\n");
		clean_up_exit(1);
	}

	switch(state) {
	case AVAHI_ENTRY_GROUP_ESTABLISHED:
		rfbLog("Avahi group %s established.\n", svc->name);
#if 0		/* is this the segv problem? */
		free(svc);
#endif
		break;
	case AVAHI_ENTRY_GROUP_COLLISION:
		new_name = avahi_alternative_service_name(svc->name);
		_avahi_create_services(new_name, svc->host, svc->port);
		rfbLog("Avahi Entry group collision\n");
		avahi_free(new_name);
		break;
	case AVAHI_ENTRY_GROUP_FAILURE:
		rfbLog("Avahi Entry group failure: %s\n",
		    avahi_strerror(avahi_client_errno(
		    avahi_entry_group_get_client(g))));
		break;
	default:
		break;
	}
if (db) fprintf(stderr, "out _avahi_entry_group_callback\n");
}

static void _avahi_create_services(const char *name, const char *host,
    const uint16_t port) {
	avahi_service_t *svc = (avahi_service_t *)malloc(sizeof(avahi_service_t));
	int ret = 0;

if (db) fprintf(stderr, "in  _avahi_create_services  %s %s %d\n", name, host, port);
	svc->name = name;
	svc->host = host;
	svc->port = port;

	if (!_group) {
if (db) fprintf(stderr, "    _avahi_create_services create group\n");
		_group = avahi_entry_group_new(_client,
		    _avahi_entry_group_callback, svc);
	}
	if (!_group) {
		rfbLog("avahi_entry_group_new() failed: %s\n",
		    avahi_strerror(avahi_client_errno(_client)));
		return;
	}

	ret = avahi_entry_group_add_service(_group, AVAHI_IF_UNSPEC,
	    AVAHI_PROTO_UNSPEC, 0, name, "_rfb._tcp", NULL, NULL, port, NULL);
	if (ret < 0) {
		rfbLog("Failed to add _rfb._tcp service: %s\n",
		    avahi_strerror(ret));
		return;
	}

	ret = avahi_entry_group_commit(_group);
	if (ret < 0) {
		rfbLog("Failed to commit entry_group:: %s\n",
		    avahi_strerror(ret));
		return;
	}
if (db) fprintf(stderr, "out _avahi_create_services\n");
}

void avahi_advertise(const char *name, const char *host, const uint16_t port) {
	int i;
if (db) fprintf(stderr, "in  avahi_advertise: %s %s %d\n", name, host, port);
	if (!_client) {
if (db) fprintf(stderr, "    avahi_advertise client null\n");
		return;
	}
	if (_poll == NULL) {
		rfbLog("Avahi poll not initialized.\n");
		return;
	}
	/* well, we just track it ourselves... */
	for (i=0; i<NREG; i++) {
		if (!registered[i].name) {
			continue;
		}
		if (strcmp(registered[i].name, name)) {
			continue;
		}
		if (strcmp(registered[i].host, host)) {
			continue;
		}
		if (registered[i].port != port) {
			continue;
		}
if (db) fprintf(stderr, "    avahi_advertise already did this one\n");
		return;
	}
	for (i=0; i<NREG; i++) {
		if (!registered[i].name) {
			registered[i].name = strdup(name);
			registered[i].host = strdup(host);
			registered[i].port = port;
			break;
		}
	}

	avahi_threaded_poll_lock(_poll);
	_avahi_create_services(name, host, port >= 5900 ? port : 5900+port);
	avahi_threaded_poll_unlock(_poll);
if (db) fprintf(stderr, "out avahi_advertise\n");
}

void avahi_reset(void) {
	int i;
if (db) fprintf(stderr, "in  avahi_reset\n");
	for (i=0; i<NREG; i++) {
		if (registered[i].name) {
			free(registered[i].name);
			registered[i].name = NULL;
		}
		if (registered[i].host) {
			free(registered[i].host);
			registered[i].host = NULL;
		}
	}
	if (!_client || !_group) {
if (db) fprintf(stderr, "    avahi_reset client/group null\n");
		return;
	}
	avahi_entry_group_reset(_group);
	rfbLog("Avahi resetting group.\n");
if (db) fprintf(stderr, "out avahi_reset\n");
}

void avahi_cleanup(void) {
if (db) fprintf(stderr, "in  avahi_cleanup\n");
	if (!_client) {
if (db) fprintf(stderr, "    avahi_cleanup client null\n");
		return;
	}
	avahi_threaded_poll_lock(_poll);
	avahi_threaded_poll_stop(_poll);

	avahi_client_free(_client);
	_client = NULL;

	avahi_threaded_poll_free(_poll);
	_poll = NULL;
if (db) fprintf(stderr, "out avahi_cleanup\n");
}

#endif