autoassign tty number

configure.ac

@@ -19,6 +19,7 @@ AS_AC_EXPAND(LIBEXECDIR, $libexecdir)
 AS_AC_EXPAND(SYSCONFDIR, $sysconfdir)
 AS_AC_EXPAND(LOCALSTATEDIR, $localstatedir)
 AS_AC_EXPAND(LXCPATH, "${localstatedir}/lib/lxc")
+AS_AC_EXPAND(LXC_GENERATE_DATE, "$(date)")
 
 AC_CHECK_HEADERS([linux/netlink.h linux/genetlink.h], [], AC_MSG_ERROR([netlink headers not found]),
 [#include <linux/types.h>

doc/lxc-console.sgml.in

@@ -45,7 +45,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   <refsynopsisdiv>
     <cmdsynopsis>
       <command>lxc-console <replaceable>-n name</replaceable>
-	<replaceable>-t ttynum</replaceable>
+	<optional>-t ttynum</optional>
       </command>
     </cmdsynopsis>
   </refsynopsisdiv>
@@ -56,7 +56,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
     <para>
       If the tty service has been configured and is available for the
       container specified as parameter, this command will launch a
-      console allowing to log to the container.
+      console allowing to log on the container.
     </para>
 
     <para>
@@ -91,11 +91,12 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 
       <varlistentry>
 	<term>
-	  <option>-t <replaceable>ttynum</replaceable></option>
+	  <option>-t <optional>ttynum</optional></option>
 	</term>
 	<listitem>
 	  <para>
-	    Specify the tty number to connect.
+	    Specify the tty number to connect, if not specified a tty
+	    number will be automatically choosen by the container.
 	  </para>
 	</listitem>
       </varlistentry>

src/lxc/console.c

@@ -45,30 +45,34 @@ extern int lxc_console(const char *name, int ttynum, int *fd)
 	sock = lxc_af_unix_connect(addr.sun_path);
 	if (sock < 0) {
 		ERROR("failed to connect to the tty service");
-		goto out_err;
+		goto out;
 	}
 
 	ret = lxc_af_unix_send_credential(sock, &ttynum, sizeof(ttynum));
 	if (ret < 0) {
 		SYSERROR("failed to send credentials");
-		goto out_err;
+		goto out_close;
 	}
 
-	ret = lxc_af_unix_recv_fd(sock, fd, NULL, 0);
+	ret = lxc_af_unix_recv_fd(sock, fd, &ttynum, sizeof(ttynum));
 	if (ret < 0) {
 		ERROR("failed to connect to the tty");
-		goto out_err;
+		goto out_close;
 	}
 
+	INFO("tty %d allocated", ttynum);
+
 	if (!ret) {
-		ERROR("tty%d denied by '%s'", ttynum, name);
+		ERROR("console denied by '%s'", name);
 		ret = -LXC_ERROR_TTY_DENIED;
-		goto out_err;
+		goto out_close;
 	}
 
 	ret = 0;
 
-out_err:
-	close(sock);
+out:
 	return ret;
+out_close:
+	close(sock);
+	goto out;
 }

src/lxc/lxc.h

@@ -120,6 +120,8 @@ extern int lxc_monitor_close(int fd);
 /*
  * Show the console of the container.
  * @name : the name of container
+ * @tty  : the tty number
+ * @fd   : a pointer to a tty file descriptor
  * Returns 0 on sucess, < 0 otherwise
  */
 extern int lxc_console(const char *name, int ttynum, int *fd);

src/lxc/lxc_console.c

@@ -47,7 +47,7 @@ void usage(char *cmd)
 {
 	fprintf(stderr, "%s <command>\n", basename(cmd));
 	fprintf(stderr, "\t -n <name>   : name of the container\n");
-	fprintf(stderr, "\t -t <tty#>   : tty number\n");
+	fprintf(stderr, "\t [-t <tty#>] : tty number\n");
 	_exit(1);
 }
 
@@ -55,9 +55,9 @@ int main(int argc, char *argv[])
 {
 	char *name = NULL;
 	int opt;
-	int ttynum = 0;
 	int nbargs = 0;
 	int master = -1;
+	int ttynum = -1;
 	int wait4q = 0;
 	int err = LXC_ERROR_INTERNAL;
 	struct termios tios, oldtios;
@@ -67,6 +67,7 @@ int main(int argc, char *argv[])
 		case 'n':
 			name = optarg;
 			break;
+
 		case 't':
 			ttynum = atoi(optarg);
 			break;
@@ -75,7 +76,7 @@ int main(int argc, char *argv[])
 		nbargs++;
 	}
 
-	if (!name || !ttynum)
+	if (!name)
 		usage(argv[0]);
 
 	/* Get current termios */

src/lxc/start.c

@@ -197,31 +197,41 @@ static int ttyservice_handler(int fd, void *data,
 	if (lxc_af_unix_rcv_credential(conn, &ttynum, sizeof(ttynum)))
 		goto out_close;
 
-	if (ttynum <= 0 || ttynum > tty_info->nbtty)
-		goto out_close;
+	if (ttynum > 0) {
+		if (ttynum > tty_info->nbtty)
+			goto out_close;
+
+		if (tty_info->pty_info[ttynum - 1].busy)
+			goto out_close;
 
-	/* fixup index array (eg. tty1 is index 0) */
-	ttynum--;
+		goto out_send;
+	}
 
-	if (tty_info->pty_info[ttynum].busy)
+	/* fixup index tty1 => [0] */
+	for (ttynum = 1;
+	     ttynum <= tty_info->nbtty && tty_info->pty_info[ttynum - 1].busy;
+	     ttynum++);
+
+	/* we didn't find any available slot for tty */
+	if (ttynum > tty_info->nbtty)
 		goto out_close;
 
-	if (lxc_af_unix_send_fd(conn, tty_info->pty_info[ttynum].master, 
-				NULL, 0) < 0) {
+out_send:
+	if (lxc_af_unix_send_fd(conn, tty_info->pty_info[ttynum - 1].master,
+				&ttynum, sizeof(ttynum)) < 0) {
 		ERROR("failed to send tty to client");
 		goto out_close;
 	}
 
-	if (lxc_mainloop_add_handler(descr, conn, 
+	if (lxc_mainloop_add_handler(descr, conn,
 				     ttyclient_handler, tty_info)) {
 		ERROR("failed to add tty client handler");
 		goto out_close;
 	}
 
-	tty_info->pty_info[ttynum].busy = conn;
+	tty_info->pty_info[ttynum - 1].busy = conn;
 
 	ret = 0;
-
 out:
 	return ret;
 out_close: