Merge "Allow the use of a custom Android DT directory" am: 6fa0884188

am: 8b2e0e03d4

Change-Id: I5c5f80c6c55ff8d7bae1f52593dec3ef6efa9908

fs_mgr/fs_mgr_boot_config.cpp

@@ -23,19 +23,11 @@
 
 #include "fs_mgr_priv.h"
 
-// Tries to get the boot config value in properties, kernel cmdline and
-// device tree (in that order).  returns 'true' if successfully found, 'false'
-// otherwise
-bool fs_mgr_get_boot_config(const std::string& key, std::string* out_val) {
+// Tries to get the given boot config value from kernel cmdline.
+// Returns true if successfully found, false otherwise.
+bool fs_mgr_get_boot_config_from_kernel_cmdline(const std::string& key, std::string* out_val) {
     FS_MGR_CHECK(out_val != nullptr);
 
-    // first check if we have "ro.boot" property already
-    *out_val = android::base::GetProperty("ro.boot." + key, "");
-    if (!out_val->empty()) {
-        return true;
-    }
-
-    // fallback to kernel cmdline, properties may not be ready yet
     std::string cmdline;
     std::string cmdline_key("androidboot." + key);
     if (android::base::ReadFileToString("/proc/cmdline", &cmdline)) {
@@ -50,9 +42,29 @@ bool fs_mgr_get_boot_config(const std::string& key, std::string* out_val) {
         }
     }
 
+    return false;
+}
+
+// Tries to get the boot config value in properties, kernel cmdline and
+// device tree (in that order).  returns 'true' if successfully found, 'false'
+// otherwise
+bool fs_mgr_get_boot_config(const std::string& key, std::string* out_val) {
+    FS_MGR_CHECK(out_val != nullptr);
+
+    // first check if we have "ro.boot" property already
+    *out_val = android::base::GetProperty("ro.boot." + key, "");
+    if (!out_val->empty()) {
+        return true;
+    }
+
+    // fallback to kernel cmdline, properties may not be ready yet
+    if (fs_mgr_get_boot_config_from_kernel_cmdline(key, out_val)) {
+        return true;
+    }
+
     // lastly, check the device tree
     if (is_dt_compatible()) {
-        std::string file_name = kAndroidDtDir + "/" + key;
+        std::string file_name = get_android_dt_dir() + "/" + key;
         if (android::base::ReadFileToString(file_name, out_val)) {
             if (!out_val->empty()) {
                 out_val->pop_back();  // Trims the trailing '\0' out.

fs_mgr/fs_mgr_fstab.cpp

@@ -29,6 +29,8 @@
 
 #include "fs_mgr_priv.h"
 
+const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android");
+
 struct fs_mgr_flag_values {
     char *key_loc;
     char *verity_loc;
@@ -358,9 +360,26 @@ static int parse_flags(char *flags, struct flag_list *fl,
     return f;
 }
 
+static std::string init_android_dt_dir() {
+    std::string android_dt_dir;
+    // The platform may specify a custom Android DT path in kernel cmdline
+    if (!fs_mgr_get_boot_config_from_kernel_cmdline("android_dt_dir", &android_dt_dir)) {
+        // Fall back to the standard procfs-based path
+        android_dt_dir = kDefaultAndroidDtDir;
+    }
+    return android_dt_dir;
+}
+
+// FIXME: The same logic is duplicated in system/core/init/
+const std::string& get_android_dt_dir() {
+    // Set once and saves time for subsequent calls to this function
+    static const std::string kAndroidDtDir = init_android_dt_dir();
+    return kAndroidDtDir;
+}
+
 static bool is_dt_fstab_compatible() {
     std::string dt_value;
-    std::string file_name = kAndroidDtDir + "/fstab/compatible";
+    std::string file_name = get_android_dt_dir() + "/fstab/compatible";
     if (read_dt_file(file_name, &dt_value)) {
         if (dt_value == "android,fstab") {
             return true;
@@ -376,7 +395,7 @@ static std::string read_fstab_from_dt() {
         return fstab;
     }
 
-    std::string fstabdir_name = kAndroidDtDir + "/fstab";
+    std::string fstabdir_name = get_android_dt_dir() + "/fstab";
     std::unique_ptr<DIR, int (*)(DIR*)> fstabdir(opendir(fstabdir_name.c_str()), closedir);
     if (!fstabdir) return fstab;
 
@@ -439,7 +458,7 @@ static std::string read_fstab_from_dt() {
 }
 
 bool is_dt_compatible() {
-    std::string file_name = kAndroidDtDir + "/compatible";
+    std::string file_name = get_android_dt_dir() + "/compatible";
     std::string dt_value;
     if (read_dt_file(file_name, &dt_value)) {
         if (dt_value == "android,firmware") {

fs_mgr/fs_mgr_priv.h

@@ -119,6 +119,7 @@ bool fs_mgr_wait_for_file(const std::string& filename,
                           const std::chrono::milliseconds relative_timeout);
 bool fs_mgr_update_for_slotselect(struct fstab *fstab);
 bool fs_mgr_is_device_unlocked();
+const std::string& get_android_dt_dir();
 bool is_dt_compatible();
 bool is_device_secure();
 int load_verity_state(struct fstab_rec* fstab, int* mode);

fs_mgr/fs_mgr_priv_boot_config.h

@@ -20,8 +20,7 @@
 #include <sys/cdefs.h>
 #include <string>
 
-const std::string kAndroidDtDir("/proc/device-tree/firmware/android");
-
+bool fs_mgr_get_boot_config_from_kernel_cmdline(const std::string& key, std::string* out_val);
 bool fs_mgr_get_boot_config(const std::string& key, std::string* out_val);
 
 #endif /* __CORE_FS_MGR_PRIV_BOOTCONFIG_H */

init/init.cpp

@@ -543,7 +543,7 @@ static void process_kernel_dt() {
         return;
     }
 
-    std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(kAndroidDtDir.c_str()), closedir);
+    std::unique_ptr<DIR, int (*)(DIR*)> dir(opendir(get_android_dt_dir().c_str()), closedir);
     if (!dir) return;
 
     std::string dt_file;
@@ -553,7 +553,7 @@ static void process_kernel_dt() {
             continue;
         }
 
-        std::string file_name = kAndroidDtDir + dp->d_name;
+        std::string file_name = get_android_dt_dir() + dp->d_name;
 
         android::base::ReadFileToString(file_name, &dt_file);
         std::replace(dt_file.begin(), dt_file.end(), ',', '.');

init/util.cpp

@@ -53,6 +53,8 @@ using namespace std::literals::string_literals;
 namespace android {
 namespace init {
 
+const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android/");
+
 // DecodeUid() - decodes and returns the given string, which can be either the
 // numeric or name representation, into the integer uid or gid. Returns
 // UINT_MAX on error.
@@ -374,10 +376,31 @@ void panic() {
     DoReboot(ANDROID_RB_RESTART2, "reboot", "bootloader", false);
 }
 
-// Reads the content of device tree file under kAndroidDtDir directory.
+static std::string init_android_dt_dir() {
+    // Use the standard procfs-based path by default
+    std::string android_dt_dir = kDefaultAndroidDtDir;
+    // The platform may specify a custom Android DT path in kernel cmdline
+    import_kernel_cmdline(false,
+                          [&](const std::string& key, const std::string& value, bool in_qemu) {
+                              if (key == "androidboot.android_dt_dir") {
+                                  android_dt_dir = value;
+                              }
+                          });
+    LOG(INFO) << "Using Android DT directory " << android_dt_dir;
+    return android_dt_dir;
+}
+
+// FIXME: The same logic is duplicated in system/core/fs_mgr/
+const std::string& get_android_dt_dir() {
+    // Set once and saves time for subsequent calls to this function
+    static const std::string kAndroidDtDir = init_android_dt_dir();
+    return kAndroidDtDir;
+}
+
+// Reads the content of device tree file under the platform's Android DT directory.
 // Returns true if the read is success, false otherwise.
 bool read_android_dt_file(const std::string& sub_path, std::string* dt_content) {
-    const std::string file_name = kAndroidDtDir + sub_path;
+    const std::string file_name = get_android_dt_dir() + sub_path;
     if (android::base::ReadFileToString(file_name, dt_content)) {
         if (!dt_content->empty()) {
             dt_content->pop_back();  // Trims the trailing '\0' out.

init/util.h

@@ -30,8 +30,6 @@
 
 #define COLDBOOT_DONE "/dev/.coldboot_done"
 
-const std::string kAndroidDtDir("/proc/device-tree/firmware/android/");
-
 using android::base::boot_clock;
 using namespace std::chrono_literals;
 
@@ -57,7 +55,10 @@ bool expand_props(const std::string& src, std::string* dst);
 
 void panic() __attribute__((__noreturn__));
 
-// Reads or compares the content of device tree file under kAndroidDtDir directory.
+// Returns the platform's Android DT directory as specified in the kernel cmdline.
+// If the platform does not configure a custom DT path, returns the standard one (based in procfs).
+const std::string& get_android_dt_dir();
+// Reads or compares the content of device tree file under the platform's Android DT directory.
 bool read_android_dt_file(const std::string& sub_path, std::string* dt_content);
 bool is_android_dt_value_expected(const std::string& sub_path, const std::string& expected_content);