nspawn: mount tmpfs on /dev/shm

Most things seem to function fine without /dev/shm, but it is expected
to be there (quoting linux/Documentation/filesystems/tmpfs.txt:
glibc 2.2 and above expects tmpfs to be mounted at /dev/shm for POSIX
shared memory (shm_open, shm_unlink)).

Since /tmp/ is already mounted as tmpfs, it would be enough to mkdir
/tmp/shm and chmod it. Mounting it separately has the advantage that
it can be easily remounted to change the quota.

diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 7f084ef2d01274a4ddefca9fa6351a9fc957e95a..770019bb8a4e2740bd43cb953d51bba3322f38d8 100644 (file)
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -273,6 +273,7 @@ static int mount_all(const char *dest) {
                 { "sysfs",     "/sys",      "sysfs", NULL,       MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true  },
                 { "tmpfs",     "/dev",      "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME,     true  },
                 { "/dev/pts",  "/dev/pts",  NULL,    NULL,       MS_BIND,                      true  },
+                { "tmpfs",     "/dev/shm",  "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true  },
                 { "tmpfs",     "/run",      "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true  },
 #ifdef HAVE_SELINUX
                 { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND,                      false },  /* Bind mount first */