[lxc-devel] [PATCH 23/24] create rslave chroot any time pivot_root fails with -EINVAL

Stéphane Graber stgraber at ubuntu.com
Tue Jan 8 17:03:13 UTC 2013


From: Serge Hallyn <serge.hallyn at ubuntu.com>

Note we still need the function to detect a MS_SHARED /, bc
if we detect that then we need to umount the chroot tmpfs
mount which lxc-start created, whose mount was forwarded to
the host mounts namespace.

Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
Acked-by: Stéphane Graber <stgraber at ubuntu.com>
---
 src/lxc/conf.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 945c3b8..09cfa9f 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1163,13 +1163,6 @@ static int setup_rootfs(struct lxc_conf *conf)
 		return -1;
 	}
 
-	if (detect_shared_rootfs()) {
-		if (chroot_into_slave(conf)) {
-			ERROR("Failed to chroot into slave /");
-			return -1;
-		}
-	}
-
 	if (mount_rootfs(rootfs->path, rootfs->mount)) {
 		ERROR("failed to mount rootfs");
 		return -1;
@@ -1180,17 +1173,33 @@ static int setup_rootfs(struct lxc_conf *conf)
 	return 0;
 }
 
-int setup_pivot_root(const struct lxc_rootfs *rootfs)
+static int setup_pivot_root(struct lxc_conf *conf)
 {
+	const struct lxc_rootfs *rootfs = &conf->rootfs;
+
 	if (!rootfs->path)
 		return 0;
 
-	if (setup_rootfs_pivot_root(rootfs->mount, rootfs->pivot)) {
+	if (setup_rootfs_pivot_root(rootfs->mount, rootfs->pivot) == 0)
+		return 0;
+
+	if (errno != EINVAL) {
 		ERROR("failed to setup pivot root");
 		return -1;
 	}
 
-	return 0;
+	INFO("pivot_root failed.  Trying pivot_root under custom chroot.");
+
+	if (chroot_into_slave(conf)) {
+		ERROR("Failed to chroot into slave /");
+		return -1;
+	}
+
+	if (setup_rootfs_pivot_root(rootfs->mount, rootfs->pivot) == 0)
+		return 0;
+
+	ERROR("failed to setup pivot root");
+	return -1;
 }
 
 static int setup_pts(int pts)
@@ -2649,7 +2658,7 @@ int lxc_setup(const char *name, struct lxc_conf *lxc_conf)
 	}
 #endif
 
-	if (setup_pivot_root(&lxc_conf->rootfs)) {
+	if (setup_pivot_root(lxc_conf)) {
 		ERROR("failed to set rootfs for '%s'", name);
 		return -1;
 	}
-- 
1.8.0





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