generator: Fixes for Android Boot environment

In Android Boot environment we do not parse ostree= karg to determine
what directory to boot into, alternatively we do this based on the
androidboot.slot_suffix= karg. But we do set ostree=true karg to denote
that we are indeed booting an ostree environment (required for some
systemd unit files). This change accounts for this approach in the
systemd generator. In this case androidboot.slot_suffix= points you to
/ostree/root.[a|b] and then that points you to the directory to boot
into in /ostree/deploy... Here is what a cmdline may look like in this
type of environment:

androidboot.slot_suffix=_a androidboot.bootdevice=*.ufshc root=PARTLABEL=system_a root=UUID=76a22bf4-f153-4541-b6c7-0332c0dfaeac rw ostree=true loglevel=4 acpi=off console=ttyAMA0 systemd.show_status=auto libahci.ignore_sss=1 slub_debug=FPZ fsck.mode=skip rcupdate.rcu_normal_after_boot=0 rcupdate.rcu_expedited=1

Signed-off-by: Eric Curtin <[email protected]>

src/libostree/ostree-impl-system-generator.c

@@ -128,8 +128,8 @@ require_internal_units (const char *normal_dir, const char *early_dir, const cha
 
 /* Generate var.mount */
 static gboolean
-fstab_generator (const char *ostree_cmdline, const char *normal_dir, const char *early_dir,
-                 const char *late_dir, GError **error)
+fstab_generator (const char *ostree_target, const bool is_aboot, const char *normal_dir,
+                 const char *early_dir, const char *late_dir, GError **error)
 {
 #ifdef HAVE_LIBMOUNT
   /* Not currently cancellable, but define a var in case we care later */
@@ -144,7 +144,8 @@ fstab_generator (const char *ostree_cmdline, const char *normal_dir, const char
    * mounted yet.
    */
   g_autofree char *stateroot = NULL;
-  if (!_ostree_sysroot_parse_bootlink (ostree_cmdline, NULL, &stateroot, NULL, NULL, error))
+  if (!_ostree_sysroot_parse_bootlink (ostree_target, is_aboot, NULL, &stateroot, NULL, NULL,
+                                       error))
     return glnx_prefix_error (error, "Parsing stateroot");
 
   /* Load /etc/fstab if it exists, and look for a /var mount */
@@ -261,17 +262,19 @@ _ostree_impl_system_generator (const char *normal_dir, const char *early_dir, co
   if (!cmdline)
     return glnx_throw (error, "Failed to read /proc/cmdline");
 
-  g_autofree char *ostree_cmdline = otcore_find_proc_cmdline_key (cmdline, "ostree");
-
+  g_autoptr (GError) otcore_get_ostree_target_error = NULL;
+  g_autofree char *ostree_target = NULL;
+  bool is_aboot = false;
   /* This could happen in CoreOS live environments, where we hackily mock
    * the `ostree=` karg for `ostree-prepare-root.service` specifically, but
    * otherwise that karg doesn't exist on the real command-line. */
-  if (!ostree_cmdline)
+  if (!otcore_get_ostree_target (cmdline, &is_aboot, &ostree_target,
+                                 &otcore_get_ostree_target_error))
     return TRUE;
 
   if (!require_internal_units (normal_dir, early_dir, late_dir, error))
     return FALSE;
-  if (!fstab_generator (ostree_cmdline, normal_dir, early_dir, late_dir, error))
+  if (!fstab_generator (ostree_target, is_aboot, normal_dir, early_dir, late_dir, error))
     return FALSE;
 
   return TRUE;

src/libostree/ostree-sysroot-private.h

@@ -19,6 +19,8 @@
 
 #pragma once
 
+#include <stdbool.h>
+
 #include "libglnx.h"
 #include "ostree-bootloader.h"
 #include "ostree.h"
@@ -177,8 +179,9 @@ gboolean _ostree_sysroot_parse_bootdir_name (const char *name, char **out_osname
 gboolean _ostree_sysroot_list_all_boot_directories (OstreeSysroot *self, char ***out_bootdirs,
                                                     GCancellable *cancellable, GError **error);
 
-gboolean _ostree_sysroot_parse_bootlink (const char *bootlink, int *out_entry_bootversion,
-                                         char **out_osname, char **out_bootcsum,
-                                         int *out_treebootserial, GError **error);
+gboolean _ostree_sysroot_parse_bootlink (const char *bootlink, const bool is_aboot,
+                                         int *out_entry_bootversion, char **out_osname,
+                                         char **out_bootcsum, int *out_treebootserial,
+                                         GError **error);
 
 G_END_DECLS

src/libostree/ostree-sysroot.c

@@ -724,24 +724,37 @@ load_origin (OstreeSysroot *self, OstreeDeployment *deployment, GCancellable *ca
 
 // Parse the kernel argument ostree=
 gboolean
-_ostree_sysroot_parse_bootlink (const char *bootlink, int *out_entry_bootversion, char **out_osname,
-                                char **out_bootcsum, int *out_treebootserial, GError **error)
+_ostree_sysroot_parse_bootlink (const char *bootlink, const bool is_aboot,
+                                int *out_entry_bootversion, char **out_osname, char **out_bootcsum,
+                                int *out_treebootserial, GError **error)
 {
   static gsize regex_initialized;
   static GRegex *regex;
+  const char *to_parse = bootlink;
+  g_autofree char *symlink_val = NULL;
+  if (is_aboot)
+    {
+      symlink_val = glnx_readlinkat_malloc (-1, bootlink, NULL, error);
+      if (!symlink_val)
+        return glnx_throw (error, "Failed to read '%s' symlink", bootlink);
+
+      to_parse = symlink_val;
+    }
+
   if (g_once_init_enter (&regex_initialized))
     {
-      regex = g_regex_new ("^/ostree/boot.([01])/([^/]+)/([^/]+)/([0-9]+)$", 0, 0, NULL);
+      regex
+          = g_regex_new (is_aboot ? "^deploy/([^/]+)/" : "^/ostree/boot.[01]/([^/]+)/", 0, 0, NULL);
       g_assert (regex);
       g_once_init_leave (&regex_initialized, 1);
     }
 
   g_autoptr (GMatchInfo) match = NULL;
-  if (!g_regex_match (regex, bootlink, 0, &match))
+  if (!g_regex_match (regex, to_parse, 0, &match))
     return glnx_throw (error,
                        "Invalid ostree= argument '%s', expected "
-                       "ostree=/ostree/boot.BOOTVERSION/OSNAME/BOOTCSUM/TREESERIAL",
-                       bootlink);
+                       "ostree=/ostree/boot.BOOTVERSION/OSNAME/BOOTCSUM/TREESERIAL or aboot method",
+                       to_parse);
 
   g_autofree char *bootversion_str = g_match_info_fetch (match, 1);
   g_autofree char *treebootserial_str = g_match_info_fetch (match, 4);
@@ -775,7 +788,10 @@ parse_deployment (OstreeSysroot *self, const char *boot_link, OstreeDeployment *
   g_autofree char *osname = NULL;
   g_autofree char *bootcsum = NULL;
   int treebootserial = -1;
-  if (!_ostree_sysroot_parse_bootlink (boot_link, &entry_boot_version, &osname, &bootcsum,
+
+  // Note is_boot should always be false here, this boot_link is taken from BLS file, not
+  // /proc/cmdline, BLS files are present in aboot images
+  if (!_ostree_sysroot_parse_bootlink (boot_link, false, &entry_boot_version, &osname, &bootcsum,
                                        &treebootserial, error))
     return FALSE;
 

src/libotcore/otcore-prepare-root.c

@@ -75,7 +75,7 @@ otcore_find_proc_cmdline_key (const char *cmdline, const char *key)
 //
 // If invalid data is found, @error will be set.
 gboolean
-otcore_get_ostree_target (const char *cmdline, char **out_target, GError **error)
+otcore_get_ostree_target (const char *cmdline, bool *is_aboot, char **out_target, GError **error)
 {
   g_assert (cmdline);
   g_assert (out_target && *out_target == NULL);
@@ -84,8 +84,10 @@ otcore_get_ostree_target (const char *cmdline, char **out_target, GError **error
 
   // First, handle the Android boot case
   g_autofree char *slot_suffix = otcore_find_proc_cmdline_key (cmdline, "androidboot.slot_suffix");
+  *is_aboot = false;
   if (slot_suffix)
     {
+      *is_aboot = true;
       if (strcmp (slot_suffix, "_a") == 0)
         {
           *out_target = g_strdup (slot_a);

src/libotcore/otcore.h

@@ -44,7 +44,8 @@ gboolean otcore_validate_ed25519_signature (GBytes *data, GBytes *pubkey, GBytes
                                             bool *out_valid, GError **error);
 
 char *otcore_find_proc_cmdline_key (const char *cmdline, const char *key);
-gboolean otcore_get_ostree_target (const char *cmdline, char **out_target, GError **error);
+gboolean otcore_get_ostree_target (const char *cmdline, bool *is_aboot, char **out_target,
+                                   GError **error);
 
 GKeyFile *otcore_load_config (int rootfs, const char *filename, GError **error);
 

src/switchroot/ostree-prepare-root.c

@@ -124,7 +124,8 @@ resolve_deploy_path (const char *root_mountpoint)
 
   g_autoptr (GError) error = NULL;
   g_autofree char *ostree_target = NULL;
-  if (!otcore_get_ostree_target (kernel_cmdline, &ostree_target, &error))
+  bool is_aboot = false;
+  if (!otcore_get_ostree_target (kernel_cmdline, &is_aboot, &ostree_target, &error))
     errx (EXIT_FAILURE, "Failed to determine ostree target: %s", error->message);
   if (!ostree_target)
     errx (EXIT_FAILURE, "No ostree target found");

tests/test-otcore.c

@@ -36,46 +36,48 @@ test_prepare_root_cmdline (void)
 {
   g_autoptr (GError) error = NULL;
   g_autofree char *target = NULL;
+  bool is_aboot = false;
 
   static const char *notfound_cases[]
       = { "", "foo", "foo=bar baz  sometest", "xostree foo", "xostree=blah bar", NULL };
   for (const char **iter = notfound_cases; iter && *iter; iter++)
     {
       const char *tcase = *iter;
-      g_assert (otcore_get_ostree_target (tcase, &target, &error));
+      g_assert (otcore_get_ostree_target (tcase, &is_aboot, &target, &error));
       g_assert_no_error (error);
       g_assert (target == NULL);
     }
 
   // Test the default ostree=
-  g_assert (otcore_get_ostree_target ("blah baz=blah ostree=/foo/bar somearg", &target, &error));
+  g_assert (otcore_get_ostree_target ("blah baz=blah ostree=/foo/bar somearg", &is_aboot, &target,
+                                      &error));
   g_assert_no_error (error);
   g_assert_cmpstr (target, ==, "/foo/bar");
   free (g_steal_pointer (&target));
 
   // Test android boot
-  g_assert (otcore_get_ostree_target ("blah baz=blah androidboot.slot_suffix=_b somearg", &target,
-                                      &error));
+  g_assert (otcore_get_ostree_target ("blah baz=blah androidboot.slot_suffix=_b somearg", &is_aboot,
+                                      &target, &error));
   g_assert_no_error (error);
   g_assert_cmpstr (target, ==, "/ostree/root.b");
   free (g_steal_pointer (&target));
 
-  g_assert (otcore_get_ostree_target ("blah baz=blah androidboot.slot_suffix=_a somearg", &target,
-                                      &error));
+  g_assert (otcore_get_ostree_target ("blah baz=blah androidboot.slot_suffix=_a somearg", &is_aboot,
+                                      &target, &error));
   g_assert_no_error (error);
   g_assert_cmpstr (target, ==, "/ostree/root.a");
   free (g_steal_pointer (&target));
 
   // And an expected failure to parse a "c" suffix
-  g_assert (!otcore_get_ostree_target ("blah baz=blah androidboot.slot_suffix=_c somearg", &target,
-                                       &error));
+  g_assert (!otcore_get_ostree_target ("blah baz=blah androidboot.slot_suffix=_c somearg",
+                                       &is_aboot, &target, &error));
   g_assert (error);
   g_assert (target == NULL);
   g_clear_error (&error);
 
   // And non-A/B androidboot
-  g_assert (otcore_get_ostree_target ("blah baz=blah androidboot.somethingelse somearg", &target,
-                                      &error));
+  g_assert (otcore_get_ostree_target ("blah baz=blah androidboot.somethingelse somearg", &is_aboot,
+                                      &target, &error));
   g_assert_no_error (error);
   g_assert_cmpstr (target, ==, "/ostree/root.a");
   free (g_steal_pointer (&target));