int platform_ssh_share(const char *pi_name, Conf *conf,
Plug downplug, Plug upplug, Socket *sock,
char **logtext, char **ds_err, char **us_err,
int can_upstream, int can_downstream)
{
char *dirname, *lockname, *sockname, *err;
int lockfd;
Socket retsock;
/*
* Sort out what we're going to call the directory in which we
* keep the socket. This has the side effect of potentially
* creating its top-level containing dir and/or the salt file
* within that, if they don't already exist.
*/
dirname = make_dirname(pi_name, logtext);
if (!dirname) {
return SHARE_NONE;
}
/*
* Now make sure the subdirectory exists.
*/
if ((err = make_dir_and_check_ours(dirname)) != NULL) {
*logtext = err;
sfree(dirname);
return SHARE_NONE;
}
/*
* Acquire a lock on a file in that directory.
*/
lockname = dupcat(dirname, "/lock", (char *)NULL);
lockfd = open(lockname, O_CREAT | O_RDWR | O_TRUNC, 0600);
if (lockfd < 0) {
*logtext = dupprintf("%s: open: %s", lockname, strerror(errno));
sfree(dirname);
sfree(lockname);
return SHARE_NONE;
}
if (flock(lockfd, LOCK_EX) < 0) {
*logtext = dupprintf("%s: flock(LOCK_EX): %s",
lockname, strerror(errno));
sfree(dirname);
sfree(lockname);
close(lockfd);
return SHARE_NONE;
}
sockname = dupprintf("%s/socket", dirname);
*logtext = NULL;
if (can_downstream) {
retsock = new_connection(unix_sock_addr(sockname),
"", 0, 0, 1, 0, 0, downplug, conf);
if (sk_socket_error(retsock) == NULL) {
sfree(*logtext);
*logtext = sockname;
*sock = retsock;
sfree(dirname);
sfree(lockname);
close(lockfd);
return SHARE_DOWNSTREAM;
}
sfree(*ds_err);
*ds_err = dupprintf("%s: %s", sockname, sk_socket_error(retsock));
sk_close(retsock);
}
if (can_upstream) {
retsock = new_unix_listener(unix_sock_addr(sockname), upplug);
if (sk_socket_error(retsock) == NULL) {
sfree(*logtext);
*logtext = sockname;
*sock = retsock;
sfree(dirname);
sfree(lockname);
close(lockfd);
return SHARE_UPSTREAM;
}
sfree(*us_err);
*us_err = dupprintf("%s: %s", sockname, sk_socket_error(retsock));
sk_close(retsock);
}
/* One of the above clauses ought to have happened. */
assert(*logtext || *ds_err || *us_err);
sfree(dirname);
sfree(lockname);
sfree(sockname);
close(lockfd);
return SHARE_NONE;
}
int platform_make_x11_server(Plug *plug, const char *progname, int mindisp,
const char *screen_number_suffix,
ptrlen authproto, ptrlen authdata,
Socket **sockets, Conf *conf)
{
char *tmpdir;
char *authfilename = NULL;
strbuf *authfiledata = NULL;
char *unix_path = NULL;
SockAddr *a_tcp = NULL, *a_unix = NULL;
int authfd;
FILE *authfp;
int displayno;
authfiledata = strbuf_new_nm();
int nsockets = 0;
/*
* Look for a free TCP port to run our server on.
*/
for (displayno = mindisp;; displayno++) {
const char *err;
int tcp_port = displayno + 6000;
int addrtype = ADDRTYPE_IPV4;
sockets[nsockets] = new_listener(
NULL, tcp_port, plug, false, conf, addrtype);
err = sk_socket_error(sockets[nsockets]);
if (!err) {
char *hostname = get_hostname();
if (hostname) {
char *canonicalname = NULL;
a_tcp = name_lookup(hostname, tcp_port, &canonicalname,
conf, addrtype, NULL, "");
sfree(canonicalname);
}
sfree(hostname);
nsockets++;
break; /* success! */
} else {
sk_close(sockets[nsockets]);
}
if (!strcmp(err, strerror(EADDRINUSE))) /* yuck! */
goto out;
}
if (a_tcp) {
x11_format_auth_for_authfile(
BinarySink_UPCAST(authfiledata),
a_tcp, displayno, authproto, authdata);
}
/*
* Try to establish the Unix-domain analogue. That may or may not
* work - file permissions in /tmp may prevent it, for example -
* but it's worth a try, and we don't consider it a fatal error if
* it doesn't work.
*/
unix_path = dupprintf("/tmp/.X11-unix/X%d", displayno);
a_unix = unix_sock_addr(unix_path);
sockets[nsockets] = new_unix_listener(a_unix, plug);
if (!sk_socket_error(sockets[nsockets])) {
x11_format_auth_for_authfile(
BinarySink_UPCAST(authfiledata),
a_unix, displayno, authproto, authdata);
nsockets++;
} else {
sk_close(sockets[nsockets]);
sfree(unix_path);
unix_path = NULL;
}
/*
* Decide where the authority data will be written.
*/
tmpdir = getenv("TMPDIR");
if (!tmpdir || !*tmpdir)
tmpdir = "/tmp";
authfilename = dupcat(tmpdir, "/", progname, "-Xauthority-XXXXXX", NULL);
{
int oldumask = umask(077);
authfd = mkstemp(authfilename);
umask(oldumask);
}
if (authfd < 0) {
while (nsockets-- > 0)
sk_close(sockets[nsockets]);
goto out;
}
/*
* Spawn a subprocess which will try to reliably delete our
* auth file when we terminate, in case we die unexpectedly.
*/
{
int cleanup_pipe[2];
pid_t pid;
/* Don't worry if pipe or fork fails; it's not _that_ critical. */
if (!pipe(cleanup_pipe)) {
if ((pid = fork()) == 0) {
int buf[1024];
/*
* Our parent process holds the writing end of
* this pipe, and writes nothing to it. Hence,
* we expect read() to return EOF as soon as
* that process terminates.
*/
close(0);
close(1);
close(2);
setpgid(0, 0);
close(cleanup_pipe[1]);
close(authfd);
while (read(cleanup_pipe[0], buf, sizeof(buf)) > 0);
unlink(authfilename);
if (unix_path)
unlink(unix_path);
_exit(0);
} else if (pid < 0) {
close(cleanup_pipe[0]);
close(cleanup_pipe[1]);
} else {
close(cleanup_pipe[0]);
cloexec(cleanup_pipe[1]);
}
}
}
authfp = fdopen(authfd, "wb");
fwrite(authfiledata->u, 1, authfiledata->len, authfp);
fclose(authfp);
{
char *display = dupprintf(":%d%s", displayno, screen_number_suffix);
conf_set_str_str(conf, CONF_environmt, "DISPLAY", display);
sfree(display);
}
conf_set_str_str(conf, CONF_environmt, "XAUTHORITY", authfilename);
/*
* FIXME: return at least the DISPLAY and XAUTHORITY env settings,
* and perhaps also the display number
*/
out:
if (a_tcp)
sk_addr_free(a_tcp);
/* a_unix doesn't need freeing, because new_unix_listener took it over */
sfree(authfilename);
strbuf_free(authfiledata);
sfree(unix_path);
return nsockets;
}
