[hacktree] parallel-debian: More in progress work...

[Colin Walters <walters src gnome org>]

commit 33232117d51c8f262d74d77e17ae2184f7e63892
Author: Colin Walters <walters verbum org>
Date:   Wed Oct 19 20:54:28 2011 -0400

    parallel-debian: More in progress work...

 parallel-debian/README-testing-multiroot.md |    6 ++++
 parallel-debian/create-wheezy-image.sh      |   16 ----------
 parallel-debian/make-image-parallel.sh      |   20 -------------
 parallel-debian/ostree_switch_root.c        |   42 +++++++++++++++++++++++---
 4 files changed, 43 insertions(+), 41 deletions(-)
---
diff --git a/parallel-debian/README-testing-multiroot.md b/parallel-debian/README-testing-multiroot.md
index 4fd0a12..1eadf88 100644
--- a/parallel-debian/README-testing-multiroot.md
+++ b/parallel-debian/README-testing-multiroot.md
@@ -2,6 +2,12 @@
 Experimenting with multiple roots
 ---------------------------------
 
+	$ mkdir gnomeos-chroot 
+	$ qemu-img create gnomeos.raw 2G
+	$ mkfs.ext2 -F gnomeos.raw
+	$ mount -o loop gnomeos.raw gnomeos-chroot
+	$ debootstrap --arch=amd64 squeeze gnomeos-chroot
+
 <http://wiki.debian.org/QEMU#Setting_up_a_testing.2BAC8-unstable_system>
 
 Follow the steps for making a disk image, downloading the business
diff --git a/parallel-debian/ostree_switch_root.c b/parallel-debian/ostree_switch_root.c
index 543dcb2..67a1cc6 100644
--- a/parallel-debian/ostree_switch_root.c
+++ b/parallel-debian/ostree_switch_root.c
@@ -143,7 +143,9 @@ static int make_readonly(const char *tree)
 
 static int switchroot(const char *newroot, const char *subroot)
 {
-	const char *root_bind_mounts[] = { "/home", "/root", "/var", NULL };
+	const char *toproot_bind_mounts[] = { "/boot", NULL };
+	const char *ostree_inherit_mounts[] = { "/home", "/root", NULL };
+	const char *ostree_bind_mounts[] = { "/var", NULL };
 	const char *readonly_bind_mounts[] = { "/bin", "/etc", "/lib",
 					       "/lib32", "/lib64", "/sbin",
 					       "/usr",
@@ -151,13 +153,23 @@ static int switchroot(const char *newroot, const char *subroot)
 	int i;
 	int orig_cfd;
 	int new_cfd;
+	int subroot_cfd;
 	pid_t pid;
+	char subroot_path[PATH_MAX];
 	char srcpath[PATH_MAX];
 	char destpath[PATH_MAX];
+	struct stat stbuf;
 
 	orig_cfd = open("/", O_RDONLY);
 	new_cfd = open(newroot, O_RDONLY);
 
+	snprintf(subroot_path, sizeof(subroot_path), "%s/ostree/%s", newroot, subroot);
+	subroot_cfd = open(subroot_path, O_RDONLY);
+	if (subroot_cfd < 0) {
+		perrorv("failed to open subroot %s", subroot_path);
+		return -1;
+	}
+
 	/* For now just remount the rootfs r/w.  Should definitely
 	 * handle this better later... (famous last words)
 	 */
@@ -166,11 +178,31 @@ static int switchroot(const char *newroot, const char *subroot)
 		return -1;
 	}
 
-	for (i = 0; root_bind_mounts[i] != NULL; i++) {
-		snprintf(srcpath, sizeof(srcpath), "%s%s", newroot, root_bind_mounts[i]);
-		snprintf(destpath, sizeof(destpath), "%s/%s%s", newroot, subroot, root_bind_mounts[i]);
+	for (i = 0; toproot_bind_mounts[i] != NULL; i++) {
+		snprintf(srcpath, sizeof(srcpath), "%s%s", newroot, toproot_bind_mounts[i]);
+		snprintf(destpath, sizeof(destpath), "%s/%s", subroot_path, toproot_bind_mounts[i]);
+		if (mount(srcpath, destpath, NULL, MS_BIND & ~MS_RDONLY, NULL) < 0) {
+			perrorv("failed to bind mount (class:toproot) %s to %s", srcpath, destpath);
+			return -1;
+		}
+	}
+
+	for (i = 0; ostree_inherit_mounts[i] != NULL; i++) {
+		snprintf(srcpath, sizeof(srcpath), "%s%s", newroot, ostree_inherit_mounts[i]);
+		if (stat (srcpath, &stbuf) < 0)
+			snprintf(srcpath, sizeof(srcpath), "%s/ostree%s", newroot, ostree_inherit_mounts[i]);
+		snprintf(destpath, sizeof(destpath), "%s%s", subroot_path, ostree_inherit_mounts[i]);
+		if (mount(srcpath, destpath, NULL, MS_BIND & ~MS_RDONLY, NULL) < 0) {
+			perrorv("failed to bind mount (class:inherit) %s to %s", srcpath, destpath);
+			return -1;
+		}
+	}
+
+	for (i = 0; ostree_bind_mounts[i] != NULL; i++) {
+		snprintf(srcpath, sizeof(srcpath), "%s/ostree%s", newroot, ostree_bind_mounts[i]);
+		snprintf(destpath, sizeof(destpath), "%s%s", subroot_path, ostree_bind_mounts[i]);
 		if (mount(srcpath, destpath, NULL, MS_BIND & ~MS_RDONLY, NULL) < 0) {
-			perrorv("failed to bind mount %s to %s", srcpath, destpath);
+			perrorv("failed to bind mount (class:bind) %s to %s", srcpath, destpath);
 			return -1;
 		}
 	}