conf: move lxc_create_ttys() before pivot root

This is the last setup step that occured after pivot root.

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

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 39bcdb1ee6394c8ba1936036af97c13289b600be..9e50692396a9ed08fc2e6cc3da1d0ed397ee110a 100644 (file)
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -961,6 +961,7 @@ static int lxc_setup_ttys(struct lxc_conf *conf)
        struct lxc_rootfs *rootfs = &conf->rootfs;
        const struct lxc_tty_info *ttys = &conf->ttys;
        char *ttydir = ttys->dir;
+       char tty_source[LXC_PROC_PID_FD_LEN], tty_target[LXC_PROC_PID_FD_LEN];
 
        if (!conf->rootfs.path)
                return 0;
@@ -1002,7 +1003,15 @@ static int lxc_setup_ttys(struct lxc_conf *conf)
                                                    PROTECT_LOOKUP_BENEATH_XDEV, 0,
                                                    false);
                        } else {
-                               ret = mount(tty->name, rootfs->buf, "none", MS_BIND, 0);
+                               ret = strnprintf(tty_source, sizeof(tty_source), "/proc/self/fd/%d", tty->pty);
+                               if (ret < 0)
+                                       return ret;
+
+                               ret = strnprintf(tty_target, sizeof(tty_target), "/proc/self/fd/%d", fd_to);
+                               if (ret < 0)
+                                       return ret;
+
+                               ret = mount(tty_source, tty_target, "none", MS_BIND, 0);
                        }
                        if (ret < 0)
                                return log_error_errno(-errno, errno,
@@ -1037,11 +1046,15 @@ static int lxc_setup_ttys(struct lxc_conf *conf)
                                                    PROTECT_LOOKUP_BENEATH, 0,
                                                    false);
                        } else {
-                               ret = strnprintf(rootfs->buf, sizeof(rootfs->buf), "/dev/tty%d", i + 1);
+                               ret = strnprintf(tty_source, sizeof(tty_source), "/proc/self/fd/%d", tty->pty);
+                               if (ret < 0)
+                                       return ret;
+
+                               ret = strnprintf(tty_target, sizeof(tty_target), "/proc/self/fd/%d", fd_to);
                                if (ret < 0)
-                                       return ret_errno(-EIO);
+                                       return ret;
 
-                               ret = mount(tty->name, rootfs->buf, "none", MS_BIND, 0);
+                               ret = mount(tty_source, tty_target, "none", MS_BIND, 0);
                        }
                        if (ret < 0)
                                return log_error_errno(-errno, errno,
@@ -1076,33 +1089,12 @@ static int lxc_allocate_ttys(struct lxc_conf *conf)
        for (size_t i = 0; i < conf->ttys.max; i++) {
                struct lxc_terminal_info *tty = &ttys->tty[i];
 
-               tty->ptx = -EBADF;
-               tty->pty = -EBADF;
-               ret = openpty(&tty->ptx, &tty->pty, NULL, NULL, NULL);
+               ret = lxc_devpts_terminal(conf->devpts_fd, conf, &tty->ptx, &tty->pty, tty->name);
                if (ret < 0) {
                        conf->ttys.max = i;
-                       return log_error_errno(-ENOTTY, ENOTTY, "Failed to create tty %zu", i);
+                       return syserror_set(-ENOTTY, "Failed to create tty %zu", i);
                }
-
-               ret = ttyname_r(tty->pty, tty->name, sizeof(tty->name));
-               if (ret < 0) {
-                       conf->ttys.max = i;
-                       return log_error_errno(-ENOTTY, ENOTTY, "Failed to retrieve name of tty %zu pty", i);
-               }
-
                DEBUG("Created tty with ptx fd %d and pty fd %d", tty->ptx, tty->pty);
-
-               /* Prevent leaking the file descriptors to the container */
-               ret = fd_cloexec(tty->ptx, true);
-               if (ret < 0)
-                       SYSWARN("Failed to set FD_CLOEXEC flag on ptx fd %d of tty device \"%s\"",
-                               tty->ptx, tty->name);
-
-               ret = fd_cloexec(tty->pty, true);
-               if (ret < 0)
-                       SYSWARN("Failed to set FD_CLOEXEC flag on pty fd %d of tty device \"%s\"",
-                               tty->pty, tty->name);
-
                tty->busy = -1;
        }
 
@@ -4228,6 +4220,10 @@ int lxc_setup(struct lxc_handler *handler)
        if (ret < 0)
                return log_error(-1, "Failed to setup console");
 
+       ret = lxc_create_ttys(handler);
+       if (ret < 0)
+               return log_error(-1, "Failed to create ttys");
+
        ret = lxc_setup_dev_symlinks(&lxc_conf->rootfs);
        if (ret < 0)
                return log_error(-1, "Failed to setup \"/dev\" symlinks");
@@ -4240,10 +4236,6 @@ int lxc_setup(struct lxc_handler *handler)
        if (lxc_conf->autodev > 0)
                (void)lxc_setup_boot_id();
 
-       ret = lxc_create_ttys(handler);
-       if (ret < 0)
-               return -1;
-
        ret = setup_personality(lxc_conf->personality);
        if (ret < 0)
                return syserror("Failed to set personality");