ostree: Mount boot partition from user space

In the current approach we assumed that boot/

- is on a separate boot partition
- boot partition is right before rootfs partition
- rootfs parition is provided as a *device node*
- has "ext2" filesystem (mount shell cmd tries to
  auto detect FS type, mount system call does not.)

The new approch does not assume any of the above, and
moves this logic from early user space (initramfs) to
user space. Initramfs by design should be used only to
prepare the rootfs, other tasks should be done later.

Change-Id: Idc429c8061c1fd486658e4b4d170ee487682cc91
Reviewed-by: Samuli Piippo <samuli.piippo@theqtcompany.com>

1 files changed, 43 insertions, 65 deletions

diff --git a/recipes/ostree/ostree/0004-Mount-boot-partition.patch b/recipes/ostree/ostree/0004-Mount-boot-partition.patch
index 092e142..a81f731 100644
--- a/recipes/ostree/ostree/0004-Mount-boot-partition.patch
+++ b/recipes/ostree/ostree/0004-Mount-boot-partition.patch
@@ -1,82 +1,60 @@
-From 5e9ed74a20026e5c9043eaf8a224ce84cb9cd9f0 Mon Sep 17 00:00:00 2001
+From 33642082578946fdc73ade8b78c05ba8d8521652 Mon Sep 17 00:00:00 2001
 From: Gatis Paeglis <gatis.paeglis@theqtcompany.com>
-Date: Mon, 7 Dec 2015 18:14:26 +0100
-Subject: [PATCH] Mount boot partition
+Date: Mon, 7 Mar 2016 15:17:34 +0100
+Subject: [PATCH] ostree: Mount boot partition from user space
 
-On b2qt reference images the boot partition always is
-the first partition on a device and rootfs is the second
-partition. We can get the root parition from a kernel
-command line and deduce the right boot partition from there.
+In the current approach we assumed that boot/
+
+- is on a separate boot partition
+- boot partition is right before rootfs partition
+- rootfs parition is provided as a *device node*
+- has "ext2" filesystem (mount shell cmd tries to
+  auto detect FS type, mount system call does not.)
+
+The new approch does not assume any of the above, and
+moves this logic from early user space (initramfs) to
+user space. Initramfs by design should be used only to
+prepare the rootfs, other tasks should be done later.
 ---
- src/switchroot/ostree-prepare-root.c | 23 ++++++++++++++++++-----
- 1 file changed, 18 insertions(+), 5 deletions(-)
+ src/switchroot/ostree-remount.c | 19 ++++++++++++++++++-
+ 1 file changed, 18 insertions(+), 1 deletion(-)
 
-diff --git a/src/switchroot/ostree-prepare-root.c b/src/switchroot/ostree-prepare-root.c
-index 3de137b..2637dc3 100644
---- a/src/switchroot/ostree-prepare-root.c
-+++ b/src/switchroot/ostree-prepare-root.c
-@@ -45,7 +45,7 @@
- #include "ostree-mount-util.h"
- 
- static char *
--parse_ostree_cmdline (void)
-+parse_kernel_cmdline (const char *arg)
+diff --git a/src/switchroot/ostree-remount.c b/src/switchroot/ostree-remount.c
+index b8d3a96..33f2645 100644
+--- a/src/switchroot/ostree-remount.c
++++ b/src/switchroot/ostree-remount.c
+@@ -77,7 +77,7 @@ maybe_mount_tmpfs_on_var (void)
+ int
+ main(int argc, char *argv[])
  {
-   FILE *f = fopen("/proc/cmdline", "r");
-   char *cmdline = NULL;
-@@ -75,9 +75,9 @@ parse_ostree_cmdline (void)
-       const char *next_nonspc = next;
-       while (next_nonspc && *next_nonspc == ' ')
-        next_nonspc += 1;
--      if (strncmp (iter, "ostree=", strlen ("ostree=")) == 0)
-+      if (strncmp (iter, arg, strlen (arg)) == 0)
-         {
--         const char *start = iter + strlen ("ostree=");
-+   const char *start = iter + strlen (arg);
-          if (next)
-            ret = strndup (start, next - start);
-          else
-@@ -114,10 +114,12 @@ main(int argc, char *argv[])
-   const char *readonly_bind_mounts[] = { "/usr", NULL };
-   const char *root_mountpoint = NULL;
-   char *ostree_target = NULL;
-+  char *boot_partition = NULL;
-   char *deploy_path = NULL;
-   char srcpath[PATH_MAX];
-   char destpath[PATH_MAX];
-   char newroot[PATH_MAX];
-+  char boot_mountpoint[PATH_MAX];
+-  const char *remounts[] = { "/sysroot", "/etc", "/home", "/root", "/tmp", "/var", NULL };
++  const char *remounts[] = { "/sysroot", "/etc", "/home", "/root", "/tmp", "/var", "/boot", NULL };
    struct stat stbuf;
    int i;
  
-@@ -129,7 +131,7 @@ main(int argc, char *argv[])
+@@ -117,5 +117,22 @@ main(int argc, char *argv[])
  
-   root_mountpoint = argv[1];
+   maybe_mount_tmpfs_on_var ();
  
--  ostree_target = parse_ostree_cmdline ();
-+  ostree_target = parse_kernel_cmdline ("ostree=");
-   if (!ostree_target)
-     {
-       fprintf (stderr, "No OSTree target; expected ostree=/ostree/boot.N/...\n");
-@@ -246,6 +248,17 @@ main(int argc, char *argv[])
-       perrorv ("failed to MS_MOVE %s to %s", deploy_path, root_mountpoint);
-       exit (EXIT_FAILURE);
-     }
--  
-+
-+  /* first partition always is the boot partition */
-+  boot_partition = parse_kernel_cmdline ("root=");
-+  boot_partition[strlen (boot_partition) - 1] = '1';
-+  /* mount the real boot parition over the deployment's boot directory */
-+  snprintf (boot_mountpoint, sizeof(boot_mountpoint), "%s/boot/", root_mountpoint);
-+  if (mount (boot_partition, boot_mountpoint, "ext2", 0, NULL) < 0)
++  /* ostree-prepare-root mounts boot/ if it is on the same partition as root filesystem.
++   * If boot/ is not mounted, then it must be on a different partition. Try to mount
++   * filesystem where LABEL=boot-ostree.
++   */
++  if (!(lstat ("/boot/loader", &stbuf) == 0 && S_ISLNK (stbuf.st_mode)))
 +    {
-+       perrorv ("failed to mount boot parition %s to %s", boot_partition, boot_mountpoint);
-+       exit (EXIT_FAILURE);
++      /* mount the real boot parition over the deployment's boot directory */
++      const char *mount_cmd="mount LABEL=boot-ostree /boot";
++      FILE *fp = popen (mount_cmd, "w");
++      if (fp == NULL)
++        {
++          perrorv ("popen failed for: %s", mount_cmd);
++          exit (EXIT_FAILURE);
++        }
++      pclose (fp);
 +    }
 +
    exit (EXIT_SUCCESS);
  }
 -- 
-2.1.4
+2.7.0