separate console device from console log

lxc-start -c makes the named file/device the container's console, but using
this with a regular file in order to get a log of the console output does
not work very well if you also want to login on the console. This change
implements an additional option (-L) to simply log the console's output to
a file.

Both options can be used separately or together. For example to get a usable
console and log: lxc-start -n name -c /dev/tty8 -L console.log

The console state is cleaned up more when lxc_delete_console is called, and
some of the clean up paths in lxc_create_console were fixed.

The lxc_priv and lxc_unpriv macros were modified to make use of gcc's local
label feature so they can be expanded more than once in the same function.

Signed-off-by: Dwight Engen <dwight.engen@oracle.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

doc/lxc-start.sgml.in

@@ -51,7 +51,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       <command>lxc-start</command>
       <arg choice="req">-n <replaceable>name</replaceable></arg>
       <arg choice="opt">-f <replaceable>config_file</replaceable></arg>
-      <arg choice="opt">-c <replaceable>console_file</replaceable></arg>
+      <arg choice="opt">-c <replaceable>console_device</replaceable></arg>
+      <arg choice="opt">-L <replaceable>console_logfile</replaceable></arg>
       <arg choice="opt">-d</arg>
       <arg choice="opt">-p <replaceable>pid_file</replaceable></arg>
       <arg choice="opt">-s KEY=VAL</arg>
@@ -75,11 +76,6 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       If no configuration is
       defined, the default isolation is used.
     </para>
-    <para>
-      The orphan process group
-      and daemon are not supported by this command, use
-      the <command>lxc-execute</command> command instead.
-    </para>
     <para>
       If no command is specified, <command>lxc-start</command> will
       use the default
@@ -139,13 +135,25 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       <varlistentry>
 	<term>
 	  <option>-c,
-	  --console <replaceable>console_file</replaceable></option>
+	  --console <replaceable>console_device</replaceable></option>
 	</term>
 	<listitem>
 	  <para>
-	    Specify a file to output the container console. If the
+	    Specify a device to use for the container's console, for example
-	    option is not specified the output will go the terminal
+            /dev/tty8. If this option is not specified the current terminal
-	    except if the <option>-d</option> is specified.
+            will be used unless <option>-d</option> is specified.
+	  </para>
+	</listitem>
+      </varlistentry>
+
+      <varlistentry>
+	<term>
+	  <option>-L,
+	  --console-log <replaceable>console_logfile</replaceable></option>
+	</term>
+	<listitem>
+	  <para>
+	    Specify a file to log the container's console output to.
 	  </para>
 	</listitem>
       </varlistentry>

src/lxc/arguments.h

@@ -45,6 +45,7 @@ struct lxc_arguments {
 	int daemonize;
 	const char *rcfile;
 	const char *console;
+	const char *console_log;
 	const char *pidfile;
 
 	/* for lxc-checkpoint/restart */

src/lxc/caps.h

@@ -33,27 +33,29 @@ extern int lxc_caps_last_cap(void);
 
 #define lxc_priv(__lxc_function)			\
 	({						\
+		__label__ out;				\
 		int __ret, __ret2, __errno = 0;		\
 		__ret = lxc_caps_up();			\
 		if (__ret)				\
-			goto __out;			\
+			goto out;			\
 		__ret = __lxc_function;			\
 		if (__ret)				\
 			__errno = errno;		\
 		__ret2 = lxc_caps_down();		\
-	__out:	__ret ? errno = __errno,__ret : __ret2;	\
+	out:	__ret ? errno = __errno,__ret : __ret2;	\
 	})
 
 #define lxc_unpriv(__lxc_function)			\
 	({						\
+		__label__ out;				\
 		int __ret, __ret2, __errno = 0;		\
 		__ret = lxc_caps_down();		\
 		if (__ret)				\
-			goto __out;			\
+			goto out;			\
 		__ret = __lxc_function;			\
 		if (__ret)				\
 			__errno = errno;		\
 		__ret2 = lxc_caps_up();			\
-	__out:	__ret ? errno = __errno,__ret : __ret2;	\
+	out:	__ret ? errno = __errno,__ret : __ret2;	\
 	})
 #endif

src/lxc/conf.c

@@ -2005,6 +2005,8 @@ struct lxc_conf *lxc_conf_init(void)
 	memset(new, 0, sizeof(*new));
 
 	new->personality = -1;
+	new->console.log_path = NULL;
+	new->console.log_fd = -1;
 	new->console.path = NULL;
 	new->console.peer = -1;
 	new->console.master = -1;

src/lxc/conf.h

@@ -175,6 +175,8 @@ struct lxc_console {
 	int master;
 	int peer;
 	char *path;
+	char *log_path;
+	int log_fd;
 	char name[MAXPATHLEN];
 	struct termios *tios;
 };

src/lxc/console.c

@@ -195,11 +195,21 @@ int lxc_create_console(struct lxc_conf *conf)
 		goto err;
 	}
 
+	if (console->log_path) {
+		fd = lxc_unpriv(open(console->log_path, O_CLOEXEC | O_RDWR | O_CREAT | O_APPEND, 0600));
+		if (fd < 0) {
+			SYSERROR("failed to open '%s'", console->log_path);
+			goto err;
+		}
+		DEBUG("using '%s' as console log", console->log_path);
+		console->log_fd = fd;
+	}
+
 	fd = lxc_unpriv(open(console->path, O_CLOEXEC | O_RDWR | O_CREAT |
 			     O_APPEND, 0600));
 	if (fd < 0) {
 		SYSERROR("failed to open '%s'", console->path);
-		goto err;
+		goto err_close_console_log;
 	}
 
 	DEBUG("using '%s' as console", console->path);
@@ -212,7 +222,7 @@ int lxc_create_console(struct lxc_conf *conf)
 	console->tios = malloc(sizeof(tios));
 	if (!console->tios) {
 		SYSERROR("failed to allocate memory");
-		goto err;
+		goto err_close_console;
 	}
 
 	/* Get termios */
@@ -241,26 +251,54 @@ int lxc_create_console(struct lxc_conf *conf)
 
 err_free:
 	free(console->tios);
+
+err_close_console:
+	close(console->peer);
+	console->peer = -1;
+
+err_close_console_log:
+	if (console->log_fd >= 0) {
+		close(console->log_fd);
+		console->log_fd = -1;
+	}
+
 err:
 	close(console->master);
+	console->master = -1;
+
 	close(console->slave);
+	console->slave = -1;
 	return -1;
 }
 
-void lxc_delete_console(const struct lxc_console *console)
+void lxc_delete_console(struct lxc_console *console)
 {
 	if (console->tios &&
 	    tcsetattr(console->peer, TCSAFLUSH, console->tios))
 		WARN("failed to set old terminal settings");
+	free(console->tios);
+	console->tios = NULL;
+
+	close(console->peer);
+	console->peer = -1;
+
+	if (console->log_fd >= 0) {
+		close(console->log_fd);
+		console->log_fd = -1;
+	}
+
 	close(console->master);
+	console->master = -1;
+
 	close(console->slave);
+	console->slave = -1;
 }
 
 static int console_handler(int fd, void *data, struct lxc_epoll_descr *descr)
 {
 	struct lxc_console *console = (struct lxc_console *)data;
 	char buf[1024];
-	int r;
+	int r,w;
 
 	r = read(fd, buf, sizeof(buf));
 	if (r < 0) {
@@ -280,10 +318,14 @@ static int console_handler(int fd, void *data, struct lxc_epoll_descr *descr)
 		return 0;
 
 	if (console->peer == fd)
-		r = write(console->master, buf, r);
+		w = write(console->master, buf, r);
-	else
+	else {
-		r = write(console->peer, buf, r);
+		w = write(console->peer, buf, r);
-
+		if (console->log_fd > 0)
+			w = write(console->log_fd, buf, r);
+	}
+	if (w != r)
+		WARN("console short write");
 	return 0;
 }
 

src/lxc/lxc_start.c

@@ -54,10 +54,46 @@ lxc_log_define(lxc_start_ui, lxc_start);
 
 static struct lxc_list defines;
 
+static int ensure_path(char **confpath, const char *path)
+{
+	int err = -1, fd;
+	char *fullpath = NULL;
+
+	if (path) {
+		if (access(path, W_OK)) {
+			fd = creat(path, 0600);
+			if (fd < 0) {
+				SYSERROR("failed to create '%s'", path);
+				goto err;
+			}
+			close(fd);
+		}
+
+		fullpath = realpath(path, NULL);
+		if (!fullpath) {
+			SYSERROR("failed to get the real path of '%s'", path);
+			goto err;
+		}
+
+		*confpath = strdup(fullpath);
+		if (!*confpath) {
+			ERROR("failed to dup string '%s'", fullpath);
+			goto err;
+		}
+	}
+	err = 0;
+
+err:
+	if (fullpath)
+		free(fullpath);
+	return err;
+}
+
 static int my_parser(struct lxc_arguments* args, int c, char* arg)
 {
 	switch (c) {
 	case 'c': args->console = arg; break;
+	case 'L': args->console_log = arg; break;
 	case 'd': args->daemonize = 1; args->close_all_fds = 1; break;
 	case 'f': args->rcfile = arg; break;
 	case 'C': args->close_all_fds = 1; break;
@@ -72,6 +108,7 @@ static const struct option my_longopts[] = {
 	{"rcfile", required_argument, 0, 'f'},
 	{"define", required_argument, 0, 's'},
 	{"console", required_argument, 0, 'c'},
+	{"console-log", required_argument, 0, 'L'},
 	{"close-all-fds", no_argument, 0, 'C'},
 	{"pidfile", required_argument, 0, 'p'},
 	LXC_COMMON_OPTIONS
@@ -89,7 +126,8 @@ Options :\n\
   -d, --daemon           daemonize the container\n\
   -p, --pidfile=FILE     Create a file with the process id\n\
   -f, --rcfile=FILE      Load configuration file FILE\n\
-  -c, --console=FILE   Set the file output for the container console\n\
+  -c, --console=FILE     Use specified FILE for the container console\n\
+  -L, --console-log=FILE Log container console output to FILE\n\
   -C, --close-all-fds    If any fds are inherited, close them\n\
                          If not specified, exit with failure instead\n\
 		         Note: --daemon implies --close-all-fds\n\
@@ -177,37 +215,16 @@ int main(int argc, char *argv[])
 		return err;
 	}
 
-	if (my_args.console) {
+	if (ensure_path(&conf->console.path, my_args.console) < 0) {
-
+		ERROR("failed to ensure console path '%s'", my_args.console);
-		char *console, fd;
-
-		if (access(my_args.console, W_OK)) {
-
-			fd = creat(my_args.console, 0600);
-			if (fd < 0) {
-				SYSERROR("failed to touch file '%s'",
-					 my_args.console);
-				return err;
-			}
-			close(fd);
-		}
-
-		console = realpath(my_args.console, NULL);
-		if (!console) {
-			SYSERROR("failed to get the real path of '%s'",
-				 my_args.console);
 		return err;
 	}
 
-		conf->console.path = strdup(console);
+	if (ensure_path(&conf->console.log_path, my_args.console_log) < 0) {
-		if (!conf->console.path) {
+		ERROR("failed to ensure console log '%s'", my_args.console_log);
-			ERROR("failed to dup string '%s'", console);
 		return err;
 	}
 
-		free(console);
-	}
-
 	if (my_args.pidfile != NULL) {
 		pid_fp = fopen(my_args.pidfile, "w");
 		if (pid_fp == NULL) {