Create DE_sys APEX data directories.

This creates the directory /data/misc/apexdata, at the same time as other
directories under /data/misc. Then, when apexd has finished activating
APEXes, a directory is created under /data/misc/apexdata for every
APEX, with the same name as the APEX module name.

See go/apex-data-directories.

APEXes are discovered by scanning the /apex directory. It may be better
to delegate this process to a library, but it is proposed to defer that
change to a future CL.

Bug: 141148175
Test: Built and flashed, checked directories were created.
Change-Id: I639d6f490ae0b97f116ce38ff3ac348bd73aa20e

1 files changed, 68 insertions, 25 deletions

diff --git a/init/builtins.cpp b/init/builtins.cpp
index 6bf399778..62a19abc5 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -360,57 +360,61 @@ static Result<void> do_interface_stop(const BuiltinArguments& args) {
     return {};
 }
 
-// mkdir <path> [mode] [owner] [group] [<option> ...]
-static Result<void> do_mkdir(const BuiltinArguments& args) {
-    auto options = ParseMkdir(args.args);
-    if (!options) return options.error();
+static Result<void> make_dir_with_options(const MkdirOptions& options) {
     std::string ref_basename;
-    if (options->ref_option == "ref") {
+    if (options.ref_option == "ref") {
         ref_basename = fscrypt_key_ref;
-    } else if (options->ref_option == "per_boot_ref") {
+    } else if (options.ref_option == "per_boot_ref") {
         ref_basename = fscrypt_key_per_boot_ref;
     } else {
-        return Error() << "Unknown key option: '" << options->ref_option << "'";
+        return Error() << "Unknown key option: '" << options.ref_option << "'";
     }
 
     struct stat mstat;
-    if (lstat(options->target.c_str(), &mstat) != 0) {
+    if (lstat(options.target.c_str(), &mstat) != 0) {
         if (errno != ENOENT) {
-            return ErrnoError() << "lstat() failed on " << options->target;
+            return ErrnoError() << "lstat() failed on " << options.target;
         }
-        if (!make_dir(options->target, options->mode)) {
-            return ErrnoErrorIgnoreEnoent() << "mkdir() failed on " << options->target;
+        if (!make_dir(options.target, options.mode)) {
+            return ErrnoErrorIgnoreEnoent() << "mkdir() failed on " << options.target;
         }
-        if (lstat(options->target.c_str(), &mstat) != 0) {
-            return ErrnoError() << "lstat() failed on new " << options->target;
+        if (lstat(options.target.c_str(), &mstat) != 0) {
+            return ErrnoError() << "lstat() failed on new " << options.target;
         }
     }
     if (!S_ISDIR(mstat.st_mode)) {
-        return Error() << "Not a directory on " << options->target;
+        return Error() << "Not a directory on " << options.target;
     }
-    bool needs_chmod = (mstat.st_mode & ~S_IFMT) != options->mode;
-    if ((options->uid != static_cast<uid_t>(-1) && options->uid != mstat.st_uid) ||
-        (options->gid != static_cast<gid_t>(-1) && options->gid != mstat.st_gid)) {
-        if (lchown(options->target.c_str(), options->uid, options->gid) == -1) {
-            return ErrnoError() << "lchown failed on " << options->target;
+    bool needs_chmod = (mstat.st_mode & ~S_IFMT) != options.mode;
+    if ((options.uid != static_cast<uid_t>(-1) && options.uid != mstat.st_uid) ||
+        (options.gid != static_cast<gid_t>(-1) && options.gid != mstat.st_gid)) {
+        if (lchown(options.target.c_str(), options.uid, options.gid) == -1) {
+            return ErrnoError() << "lchown failed on " << options.target;
         }
         // chown may have cleared S_ISUID and S_ISGID, chmod again
         needs_chmod = true;
     }
     if (needs_chmod) {
-        if (fchmodat(AT_FDCWD, options->target.c_str(), options->mode, AT_SYMLINK_NOFOLLOW) == -1) {
-            return ErrnoError() << "fchmodat() failed on " << options->target;
+        if (fchmodat(AT_FDCWD, options.target.c_str(), options.mode, AT_SYMLINK_NOFOLLOW) == -1) {
+            return ErrnoError() << "fchmodat() failed on " << options.target;
         }
     }
     if (fscrypt_is_native()) {
-        if (!FscryptSetDirectoryPolicy(ref_basename, options->fscrypt_action, options->target)) {
+        if (!FscryptSetDirectoryPolicy(ref_basename, options.fscrypt_action, options.target)) {
             return reboot_into_recovery(
-                    {"--prompt_and_wipe_data", "--reason=set_policy_failed:"s + options->target});
+                    {"--prompt_and_wipe_data", "--reason=set_policy_failed:"s + options.target});
         }
     }
     return {};
 }
 
+// mkdir <path> [mode] [owner] [group] [<option> ...]
+static Result<void> do_mkdir(const BuiltinArguments& args) {
+    auto options = ParseMkdir(args.args);
+    if (!options) return options.error();
+    return make_dir_with_options(*options);
+}
+
 /* umount <path> */
 static Result<void> do_umount(const BuiltinArguments& args) {
     if (umount(args[1].c_str()) < 0) {
@@ -1172,7 +1176,7 @@ static Result<void> do_mark_post_data(const BuiltinArguments& args) {
     return {};
 }
 
-static Result<void> do_parse_apex_configs(const BuiltinArguments& args) {
+static Result<void> parse_apex_configs() {
     glob_t glob_result;
     static constexpr char glob_pattern[] = "/apex/*/etc/*.rc";
     const int ret = glob(glob_pattern, GLOB_MARK, nullptr, &glob_result);
@@ -1211,6 +1215,45 @@ static Result<void> do_parse_apex_configs(const BuiltinArguments& args) {
     }
 }
 
+/*
+ * Creates a directory under /data/misc/apexdata/ for each APEX.
+ */
+static Result<void> create_apex_data_dirs() {
+    auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/apex"), closedir);
+    if (!dirp) {
+        return ErrnoError() << "Unable to open apex directory";
+    }
+    struct dirent* entry;
+    while ((entry = readdir(dirp.get())) != nullptr) {
+        if (entry->d_type != DT_DIR) continue;
+
+        const char* name = entry->d_name;
+        // skip any starting with "."
+        if (name[0] == '.') continue;
+
+        if (strchr(name, '@') != nullptr) continue;
+
+        auto path = "/data/misc/apexdata/" + std::string(name);
+        auto system_uid = DecodeUid("system");
+        auto options =
+                MkdirOptions{path, 0700, *system_uid, *system_uid, FscryptAction::kNone, "ref"};
+        make_dir_with_options(options);
+    }
+    return {};
+}
+
+static Result<void> do_perform_apex_config(const BuiltinArguments& args) {
+    auto create_dirs = create_apex_data_dirs();
+    if (!create_dirs) {
+        return create_dirs.error();
+    }
+    auto parse_configs = parse_apex_configs();
+    if (!parse_configs) {
+        return parse_configs.error();
+    }
+    return {};
+}
+
 static Result<void> do_enter_default_mount_ns(const BuiltinArguments& args) {
     if (SwitchToDefaultMountNamespace()) {
         return {};
@@ -1271,7 +1314,7 @@ const BuiltinFunctionMap& GetBuiltinFunctionMap() {
         // mount and umount are run in the same context as mount_all for symmetry.
         {"mount_all",               {1,     kMax, {false,  do_mount_all}}},
         {"mount",                   {3,     kMax, {false,  do_mount}}},
-        {"parse_apex_configs",      {0,     0,    {false,  do_parse_apex_configs}}},
+        {"perform_apex_config",     {0,     0,    {false,  do_perform_apex_config}}},
         {"umount",                  {1,     1,    {false,  do_umount}}},
         {"umount_all",              {1,     1,    {false,  do_umount_all}}},
         {"readahead",               {1,     2,    {true,   do_readahead}}},