console: fail when we cannot allocate peer tty

There's really no reason not to if it's requested.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/console.c b/src/lxc/console.c
index 0cfc9ab84e41777ade1615bcb8a154748c955551..3baaed49844199df3b8bb62489b62ce3afe07b2b 100644 (file)
--- a/src/lxc/console.c
+++ b/src/lxc/console.c
@@ -415,16 +415,17 @@ void lxc_console_free(struct lxc_conf *conf, int fd)
        }
 }
 
-static void lxc_console_peer_default(struct lxc_console *console)
+static int lxc_console_peer_default(struct lxc_console *console)
 {
        struct lxc_tty_state *ts;
        const char *path = console->path;
+       int fd;
+       int ret = 0;
 
-       /* if no console was given, try current controlling terminal, there
-        * won't be one if we were started as a daemon (-d)
+       /* If no console was given, try current controlling terminal, there
+        * won't be one if we were started as a daemon (-d).
         */
        if (!path && !access("/dev/tty", F_OK)) {
-               int fd;
                fd = open("/dev/tty", O_RDWR);
                if (fd >= 0) {
                        close(fd);
@@ -432,25 +433,29 @@ static void lxc_console_peer_default(struct lxc_console *console)
                }
        }
 
-       if (!path)
-               goto out;
-
-       DEBUG("opening %s for console peer", path);
-       console->peer = lxc_unpriv(open(path, O_CLOEXEC | O_RDWR | O_CREAT |
-                                       O_APPEND, 0600));
-       if (console->peer < 0)
+       if (!path) {
+               errno = ENOTTY;
+               DEBUG("process does not have a controlling terminal");
                goto out;
+       }
 
-       DEBUG("using '%s' as console", path);
+       console->peer = lxc_unpriv(open(path, O_CLOEXEC | O_RDWR | O_CREAT | O_APPEND, 0600));
+       if (console->peer < 0) {
+               ERROR("failed to open \"%s\"", path);
+               return -ENOTTY;
+       }
+       DEBUG("using \"%s\" as peer tty device", path);
 
-       if (!isatty(console->peer))
-               goto err1;
+       if (!isatty(console->peer)) {
+               ERROR("file descriptor for file \"%s\" does not refer to a tty device", path);
+               goto on_error1;
+       }
 
        ts = lxc_console_sigwinch_init(console->peer, console->master);
        console->tty_state = ts;
        if (!ts) {
-               WARN("Unable to install SIGWINCH");
-               goto err1;
+               WARN("unable to install SIGWINCH handler");
+               goto on_error1;
        }
 
        lxc_console_winsz(console->peer, console->master);
@@ -458,23 +463,27 @@ static void lxc_console_peer_default(struct lxc_console *console)
        console->tios = malloc(sizeof(*console->tios));
        if (!console->tios) {
                SYSERROR("failed to allocate memory");
-               goto err1;
+               ret = -ENOMEM;
+               goto on_error1;
        }
 
        if (lxc_setup_tios(console->peer, console->tios) < 0)
-               goto err2;
-
-       return;
+               goto on_error2;
+       else
+               goto out;
 
-err2:
+on_error2:
        free(console->tios);
        console->tios = NULL;
-err1:
+       ret = -ENOTTY;
+
+on_error1:
        close(console->peer);
        console->peer = -1;
+       ret = -ENOTTY;
+
 out:
-       DEBUG("no console peer");
-       return;
+       return ret;
 }
 
 void lxc_console_delete(struct lxc_console *console)
@@ -503,21 +512,24 @@ int lxc_console_create(struct lxc_conf *conf)
        int ret;
 
        if (conf->is_execute) {
-               INFO("no console for lxc-execute.");
+               INFO("not allocating a console device for lxc-execute.");
                return 0;
        }
 
-       if (!conf->rootfs.path)
+       if (!conf->rootfs.path) {
+               INFO("container does not have a rootfs, console device will be shared with the host");
                return 0;
+       }
 
-       if (console->path && !strcmp(console->path, "none"))
+       if (console->path && !strcmp(console->path, "none")) {
+               INFO("no console requested");
                return 0;
+       }
 
        process_lock();
-       ret = openpty(&console->master, &console->slave,
-                   console->name, NULL, NULL);
+       ret = openpty(&console->master, &console->slave, console->name, NULL, NULL);
        process_unlock();
-       if (ret) {
+       if (ret < 0) {
                SYSERROR("failed to allocate a pty");
                return -1;
        }
@@ -532,17 +544,19 @@ int lxc_console_create(struct lxc_conf *conf)
                goto err;
        }
 
-       lxc_console_peer_default(console);
+       ret = lxc_console_peer_default(console);
+       if (ret < 0) {
+               ERROR("failed to allocate peer tty device");
+               goto err;
+       }
 
        if (console->log_path) {
-               console->log_fd = lxc_unpriv(open(console->log_path,
-                                                 O_CLOEXEC | O_RDWR |
-                                                 O_CREAT | O_APPEND, 0600));
+               console->log_fd = lxc_unpriv(open(console->log_path, O_CLOEXEC | O_RDWR | O_CREAT | O_APPEND, 0600));
                if (console->log_fd < 0) {
-                       SYSERROR("failed to open '%s'", console->log_path);
+                       SYSERROR("failed to open console log file \"%s\"", console->log_path);
                        goto err;
                }
-               DEBUG("using '%s' as console log", console->log_path);
+               DEBUG("using \"%s\" as console log file", console->log_path);
        }
 
        return 0;