[libvirt] [PATCH] lxc: Bind mount container TTYs

[Martin Kletzander]

On Tue, Jun 23, 2015 at 04:38:57PM +0200, Richard Weinberger wrote:
>Instead of creating symlinks, bind mount the devices to
>/dev/pts/XY.
>Using bind mounts it is no longer needed to add pts devices
>to files like /dev/securetty.
>
>Signed-off-by: Richard Weinberger <richard at nod.at>
>---
> src/lxc/lxc_container.c | 38 +++++++++++++++++++++-----------------
> 1 file changed, 21 insertions(+), 17 deletions(-)
>

I spent ridiculously excessive time on this not working for me, but I
just figured out that simple check whether that file is a symlink or
not (inside the container) is enough.  Ant it works.

ACK then, sorry for wasting your time with this as well.

>diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
>index 7d531e2..ea76370 100644
>--- a/src/lxc/lxc_container.c
>+++ b/src/lxc/lxc_container.c
>@@ -1141,6 +1141,20 @@ static int lxcContainerMountFSDevPTS(virDomainDefPtr def,
>     return ret;
> }
>
>+static int lxcContainerBindMountDevice(const char *src, const char *dst)
>+{
>+    if (virFileTouch(dst, 0666) < 0)
>+        return -1;
>+
>+    if (mount(src, dst, "none", MS_BIND, NULL) < 0) {
>+        virReportSystemError(errno, _("Failed to bind %s on to %s"), src,
>+                             dst);
>+        return -1;
>+    }
>+
>+    return 0;
>+}
>+
> static int lxcContainerSetupDevices(char **ttyPaths, size_t nttyPaths)
> {
>     size_t i;
>@@ -1164,34 +1178,24 @@ static int lxcContainerSetupDevices(char **ttyPaths, size_t nttyPaths)
>     }
>
>     /* We have private devpts capability, so bind that */
>-    if (virFileTouch("/dev/ptmx", 0666) < 0)
>+    if (lxcContainerBindMountDevice("/dev/pts/ptmx", "/dev/ptmx") < 0)
>         return -1;
>
>-    if (mount("/dev/pts/ptmx", "/dev/ptmx", "ptmx", MS_BIND, NULL) < 0) {
>-        virReportSystemError(errno, "%s",
>-                             _("Failed to bind /dev/pts/ptmx on to /dev/ptmx"));
>-        return -1;
>-    }
>-
>     for (i = 0; i < nttyPaths; i++) {
>         char *tty;
>         if (virAsprintf(&tty, "/dev/tty%zu", i+1) < 0)
>             return -1;
>-        if (symlink(ttyPaths[i], tty) < 0) {
>-            virReportSystemError(errno,
>-                                 _("Failed to symlink %s to %s"),
>-                                 ttyPaths[i], tty);
>-            VIR_FREE(tty);
>+
>+        if (lxcContainerBindMountDevice(ttyPaths[i], tty) < 0) {
>             return -1;
>+            VIR_FREE(tty);
>         }
>+
>         VIR_FREE(tty);
>+
>         if (i == 0 &&
>-            symlink(ttyPaths[i], "/dev/console") < 0) {
>-            virReportSystemError(errno,
>-                                 _("Failed to symlink %s to /dev/console"),
>-                                 ttyPaths[i]);
>+            lxcContainerBindMountDevice(ttyPaths[i], "/dev/console") < 0)
>             return -1;
>-        }
>     }
>     return 0;
> }
>--
>2.4.2
>
>--
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