探索platform.xml
前言：最近工作涉及到platform.xml的修改，其中涉及的條目還是挺多的，就着週末有時間梳理一下。
擴展閱讀：
1.doze模式： https://developer.android.com/training/monitoring-device-state/doze-standby?hl=zh-cn
2. https://blog.csdn.net/licaomengRICE/article/details/48735957
1. platform.xml存放位置
platform.xml其實是將aosp中的配置文件直接拷貝到手機目錄中
1.1 手機存放位置
如下所示，手機中所存放的位置是位於/system/etc/permissions下
1.2 aosp中位置
在aosp中是放在framework/base/data/etc/下的
2. platform.xml內容
摘自小米mix 2:
<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2008 The Android Open Source Project
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- This file is used to define the mappings between lower-level system
user and group IDs and the higher-level permission names managed
by the platform.
Be VERY careful when editing this file! Mistakes made here can open
big security holes.
-->
<permissions>
<!-- ================================================================== -->
<!-- ================================================================== -->
<!-- ================================================================== -->
<!-- The following tags are associating low-level group IDs with
permission names. By specifying such a mapping, you are saying
that any application process granted the given permission will
also be running with the given group ID attached to its process,
so it can perform any filesystem (read, write, execute) operations
allowed for that group. -->
<permission name="android.permission.BLUETOOTH_ADMIN" >
<group gid="net_bt_admin" />
</permission>
<permission name="android.permission.BLUETOOTH" >
<group gid="net_bt" />
</permission>
<permission name="android.permission.BLUETOOTH_STACK" >
<group gid="bluetooth" />
<group gid="wakelock" />
</permission>
<permission name="android.permission.NET_TUNNELING" >
<group gid="vpn" />
</permission>
<permission name="android.permission.INTERNET" >
<group gid="inet" />
</permission>
<permission name="android.permission.READ_LOGS" >
<group gid="log" />
</permission>
<permission name="android.permission.WRITE_MEDIA_STORAGE" >
<group gid="media_rw" />
<group gid="sdcard_rw" />
</permission>
<permission name="android.permission.ACCESS_MTP" >
<group gid="mtp" />
</permission>
<permission name="android.permission.NET_ADMIN" >
<group gid="net_admin" />
</permission>
<!-- The group that /cache belongs to, linked to the permission
set on the applications that can access /cache -->
<permission name="android.permission.ACCESS_CACHE_FILESYSTEM" >
<group gid="cache" />
</permission>
<!-- RW permissions to any system resources owned by group 'diag'.
This is for carrier and manufacture diagnostics tools that must be
installable from the framework. Be careful. -->
<permission name="android.permission.DIAGNOSTIC" >
<group gid="input" />
<group gid="diag" />
</permission>
<!-- Group that can read detailed network usage statistics -->
<permission name="android.permission.READ_NETWORK_USAGE_HISTORY">
<group gid="net_bw_stats" />
</permission>
<!-- Group that can modify how network statistics are accounted -->
<permission name="android.permission.MODIFY_NETWORK_ACCOUNTING">
<group gid="net_bw_acct" />
</permission>
<permission name="android.permission.LOOP_RADIO" >
<group gid="loop_radio" />
</permission>
<!-- Hotword training apps sometimes need a GID to talk with low-level
hardware; give them audio for now until full HAL support is added. -->
<permission name="android.permission.MANAGE_VOICE_KEYPHRASES">
<group gid="audio" />
</permission>
<permission name="android.permission.ACCESS_FM_RADIO" >
<!-- /dev/fm is gid media, not audio -->
<group gid="media" />
</permission>
<!-- These are permissions that were mapped to gids but we need
to keep them here until an upgrade from L to the current
version is to be supported. These permissions are built-in
and in L were not stored in packages.xml as a result if they
are not defined here while parsing packages.xml we would
ignore these permissions being granted to apps and not
propagate the granted state. From N we are storing the
built-in permissions in packages.xml as the saved storage
is negligible (one tag with the permission) compared to
the fragility as one can remove a built-in permission which
no longer needs to be mapped to gids and break grant propagation. -->
<permission name="android.permission.READ_EXTERNAL_STORAGE" />
<permission name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!-- ================================================================== -->
<!-- ================================================================== -->
<!-- ================================================================== -->
<!-- The following tags are assigning high-level permissions to specific
user IDs. These are used to allow specific core system users to
perform the given operations with the higher-level framework. For
example, we give a wide variety of permissions to the shell user
since that is the user the adb shell runs under and developers and
others should have a fairly open environment in which to
interact with the system. -->
<assign-permission name="android.permission.MODIFY_AUDIO_SETTINGS" uid="media" />
<assign-permission name="android.permission.ACCESS_SURFACE_FLINGER" uid="media" />
<assign-permission name="android.permission.WAKE_LOCK" uid="media" />
<assign-permission name="android.permission.UPDATE_DEVICE_STATS" uid="media" />
<assign-permission name="android.permission.UPDATE_APP_OPS_STATS" uid="media" />
<assign-permission name="android.permission.GET_PROCESS_STATE_AND_OOM_SCORE" uid="media" />
<assign-permission name="android.permission.MODIFY_AUDIO_SETTINGS" uid="audioserver" />
<assign-permission name="android.permission.ACCESS_SURFACE_FLINGER" uid="audioserver" />
<assign-permission name="android.permission.WAKE_LOCK" uid="audioserver" />
<assign-permission name="android.permission.UPDATE_DEVICE_STATS" uid="audioserver" />
<assign-permission name="android.permission.UPDATE_APP_OPS_STATS" uid="audioserver" />
<assign-permission name="android.permission.MODIFY_AUDIO_SETTINGS" uid="cameraserver" />
<assign-permission name="android.permission.ACCESS_SURFACE_FLINGER" uid="cameraserver" />
<assign-permission name="android.permission.WAKE_LOCK" uid="cameraserver" />
<assign-permission name="android.permission.UPDATE_DEVICE_STATS" uid="cameraserver" />
<assign-permission name="android.permission.UPDATE_APP_OPS_STATS" uid="cameraserver" />
<assign-permission name="android.permission.GET_PROCESS_STATE_AND_OOM_SCORE" uid="cameraserver" />
<assign-permission name="android.permission.ACCESS_SURFACE_FLINGER" uid="graphics" />
<!-- MIUI ADD -->
<!-- for bootaudio setVolumeIndex-->
<assign-permission name="android.permission.MODIFY_AUDIO_SETTINGS" uid="graphics" />
<!-- This is a list of all the libraries available for application
code to link against. -->
<library name="android.test.runner"
file="/system/framework/android.test.runner.jar" />
<library name="javax.obex"
file="/system/framework/javax.obex.jar" />
<library name="org.apache.http.legacy"
file="/system/framework/org.apache.http.legacy.jar" />
<!-- These are the standard packages that are white-listed to always have internet
access while in power save mode, even if they aren't in the foreground. -->
<allow-in-power-save package="com.android.providers.downloads" />
<!-- These are the standard packages that are white-listed to always have internet
access while in data mode, even if they aren't in the foreground. -->
<allow-in-data-usage-save package="com.android.providers.downloads" />
<!-- This is a core platform component that needs to freely run in the background -->
<allow-in-power-save package="com.android.cellbroadcastreceiver" />
<allow-in-power-save package="com.android.shell" />
<!-- These are the packages that are white-listed to be able to run as system user -->
<system-user-whitelisted-app package="com.android.settings" />
<!-- These are the packages that shouldn't run as system user -->
<system-user-blacklisted-app package="com.android.wallpaper.livepicker" />
</permissions>
3. platform.xml內容梳理
關鍵tag:
<permission>
<assign-permission>
<library>
<allow-in-power-save>
<allow-in-data-usage-save>
<system-user-whitelisted-app>
<system-user-blacklisted-app>
3.1 警告部分
說明這個文件是處理普通用戶和系統權限之間映射的，如果擅自改動，會造成大的安全漏洞。
<!-- This file is used to define the mappings between lower-level system
user and group IDs and the higher-level permission names managed
by the platform.
Be VERY careful when editing this file! Mistakes made here can open
big security holes.
-->
3.2 權限映射
<permission>將低等級的groups id和權限名稱相關聯。通過指定這樣的映射，表明了一個授予了給定權限的應用進程將附帶這所給的group id運行，因此它可以執行這個羣組所允許的讀寫和執行操作。
<!-- The following tags are associating low-level group IDs with
permission names. By specifying such a mapping, you are saying
that any application process granted the given permission will
also be running with the given group ID attached to its process,
so it can perform any filesystem (read, write, execute) operations
allowed for that group. -->
<permission name="android.permission.BLUETOOTH_ADMIN" >
<group gid="net_bt_admin" />
</permission>
有個例外：
<!-- These are permissions that were mapped to gids but we need
to keep them here until an upgrade from L to the current
version is to be supported. These permissions are built-in
and in L were not stored in packages.xml as a result if they
are not defined here while parsing packages.xml we would
ignore these permissions being granted to apps and not
propagate the granted state. From N we are storing the
built-in permissions in packages.xml as the saved storage
is negligible (one tag with the permission) compared to
the fragility as one can remove a built-in permission which
no longer needs to be mapped to gids and break grant propagation. -->
<permission name="android.permission.READ_EXTERNAL_STORAGE" />
<permission name="android.permission.WRITE_EXTERNAL_STORAGE" />
3.3 分配權限
<assign-permission>:有些用戶比較特殊，它們是系統核心用戶，Android會分配特定的高級權限來允許它們來完成一些高級的操作。比如，shell用戶有很多權限，這是因爲開發者需要比較開放的環境來和system進行交互。
shell用戶的權限有時候需要adb root/adb remount才能享受，對應的需要userdebug或者root版本，user版本下shell命令還是有所限制的。
<!-- The following tags are assigning high-level permissions to specific
user IDs. These are used to allow specific core system users to
perform the given operations with the higher-level framework. For
example, we give a wide variety of permissions to the shell user
since that is the user the adb shell runs under and developers and
others should have a fairly open environment in which to
interact with the system. -->
<assign-permission name="android.permission.MODIFY_AUDIO_SETTINGS" uid="media" />
<assign-permission name="android.permission.ACCESS_SURFACE_FLINGER" uid="media" />
3.4 庫
<library>:應用可以鏈接到的庫，可以理解爲應用可以調用到的jar？
<!-- This is a list of all the libraries available for application
code to link against. -->
<library name="android.test.runner"
file="/system/framework/android.test.runner.jar" />
<library name="javax.obex"
file="/system/framework/javax.obex.jar" />
<library name="org.apache.http.legacy"
file="/system/framework/org.apache.http.legacy.jar" />
3.5 省電優化白名單
<allow-in-power-save>: 這個對應於手機中的省電優化設置，用這個tag配置在這張表中就代表該應用不受省電優化顯示，可以在後臺訪問網絡。對應應用在原生設置中的電源菜單也是灰顯，不可設置優化的。
<!-- These are the standard packages that are white-listed to always have internet
access while in power save mode, even if they aren't in the foreground. -->
<allow-in-power-save package="com.android.providers.downloads" />
<!-- This is a core platform component that needs to freely run in the background -->
<allow-in-power-save package="com.android.cellbroadcastreceiver" />
<allow-in-power-save package="com.android.shell" />
這個tag也和doze mode有些關係
可以使用命令查看：adb shell dumpsys deviceidle whitelist
chiron:/system/etc/permissions $ dumpsys deviceidle whitelist
system-excidle,com.android.providers.downloads,10012
system-excidle,com.qualcomm.qti.telephonyservice,1001
system-excidle,com.qualcomm.qti.radioconfiginterface,1001
system-excidle,com.android.cellbroadcastreceiver,10007
system-excidle,com.qualcomm.qti.ims,1001
system-excidle,com.android.shell,2000
system,com.android.providers.downloads,10012
system,com.qualcomm.qti.telephonyservice,1001
system,com.qualcomm.qti.radioconfiginterface,1001
system,com.android.cellbroadcastreceiver,10007
system,com.qualcomm.qti.ims,1001
system,com.android.shell,2000
user,com.android.cts.priv.ctsshim,10009
user,com.qualcomm.qti.auth.sampleextauthservice,10077
user,com.miui.contentextension,10113
user,com.unionpay.tsmservice.mi,10086
3.6 數據白名單
<!-- These are the standard packages that are white-listed to always have internet
access while in data mode, even if they aren't in the foreground. -->
<allow-in-data-usage-save package="com.android.providers.downloads" />
3.7 系統應用白名單
<!-- These are the packages that are white-listed to be able to run as system user -->
<system-user-whitelisted-app package="com.android.settings" />
設置是系統應用，可以看它的AndroidManifest.xml：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:androidprv="http://schemas.android.com/apk/prv/res/android"
package="com.android.settings"
coreApp="true"
android:sharedUserId="android.uid.system">
這表明了設置uid是1000，並且是核心應用。
3.8 系統應用黑名單
<!-- These are the packages that shouldn't run as system user -->
<system-user-blacklisted-app package="com.android.wallpaper.livepicker" />
4. platform.xml對應的解析代碼
xml肯定是需要解析才能用的，/frameworks/core/java/com/android/server/SystemConfig.java 這個SystemConfig就是來解析platform.xml，然後供一個個系統接口用作返回值的依據。
void readPermissions(File libraryDir, int permissionFlag) {
// Read permissions from given directory.
if (!libraryDir.exists() || !libraryDir.isDirectory()) {
if (permissionFlag == ALLOW_ALL) {
Slog.w(TAG, "No directory " + libraryDir + ", skipping");
}
return;
}
if (!libraryDir.canRead()) {
Slog.w(TAG, "Directory " + libraryDir + " cannot be read");
return;
}
// Iterate over the files in the directory and scan .xml files
File platformFile = null;
for (File f : libraryDir.listFiles()) {
// We'll read platform.xml last
if (f.getPath().endsWith("etc/permissions/platform.xml")) {
platformFile = f;
continue;
}
if (!f.getPath().endsWith(".xml")) {
Slog.i(TAG, "Non-xml file " + f + " in " + libraryDir + " directory, ignoring");
continue;
}
if (!f.canRead()) {
Slog.w(TAG, "Permissions library file " + f + " cannot be read");
continue;
}
readPermissionsFromXml(f, permissionFlag);
}
// Read platform permissions last so it will take precedence
if (platformFile != null) {
readPermissionsFromXml(platformFile, permissionFlag);
}
}
private void readPermissionsFromXml(File permFile, int permissionFlag) {
FileReader permReader = null;
try {
permReader = new FileReader(permFile);
} catch (FileNotFoundException e) {
Slog.w(TAG, "Couldn't find or open permissions file " + permFile);
return;
}
final boolean lowRam = ActivityManager.isLowRamDeviceStatic();
try {
XmlPullParser parser = Xml.newPullParser();
parser.setInput(permReader);
int type;
while ((type=parser.next()) != parser.START_TAG
&& type != parser.END_DOCUMENT) {
;
}
if (type != parser.START_TAG) {
throw new XmlPullParserException("No start tag found");
}
if (!parser.getName().equals("permissions") && !parser.getName().equals("config")) {
throw new XmlPullParserException("Unexpected start tag in " + permFile
+ ": found " + parser.getName() + ", expected 'permissions' or 'config'");
}
boolean allowAll = permissionFlag == ALLOW_ALL;
boolean allowLibs = (permissionFlag & ALLOW_LIBS) != 0;
boolean allowFeatures = (permissionFlag & ALLOW_FEATURES) != 0;
boolean allowPermissions = (permissionFlag & ALLOW_PERMISSIONS) != 0;
boolean allowAppConfigs = (permissionFlag & ALLOW_APP_CONFIGS) != 0;
boolean allowPrivappPermissions = (permissionFlag & ALLOW_PRIVAPP_PERMISSIONS) != 0;
boolean allowApiWhitelisting = (permissionFlag & ALLOW_HIDDENAPI_WHITELISTING) != 0;
while (true) {
XmlUtils.nextElement(parser);
if (parser.getEventType() == XmlPullParser.END_DOCUMENT) {
break;
}
String name = parser.getName();
if ("group".equals(name) && allowAll) {
String gidStr = parser.getAttributeValue(null, "gid");
if (gidStr != null) {
int gid = android.os.Process.getGidForName(gidStr);
mGlobalGids = appendInt(mGlobalGids, gid);
} else {
Slog.w(TAG, "<group> without gid in " + permFile + " at "
+ parser.getPositionDescription());
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("permission".equals(name) && allowPermissions) {
String perm = parser.getAttributeValue(null, "name");
if (perm == null) {
Slog.w(TAG, "<permission> without name in " + permFile + " at "
+ parser.getPositionDescription());
XmlUtils.skipCurrentTag(parser);
continue;
}
perm = perm.intern();
readPermission(parser, perm);
} else if ("assign-permission".equals(name) && allowPermissions) {
String perm = parser.getAttributeValue(null, "name");
if (perm == null) {
Slog.w(TAG, "<assign-permission> without name in " + permFile + " at "
+ parser.getPositionDescription());
XmlUtils.skipCurrentTag(parser);
continue;
}
String uidStr = parser.getAttributeValue(null, "uid");
if (uidStr == null) {
Slog.w(TAG, "<assign-permission> without uid in " + permFile + " at "
+ parser.getPositionDescription());
XmlUtils.skipCurrentTag(parser);
continue;
}
int uid = Process.getUidForName(uidStr);
if (uid < 0) {
Slog.w(TAG, "<assign-permission> with unknown uid \""
+ uidStr + " in " + permFile + " at "
+ parser.getPositionDescription());
XmlUtils.skipCurrentTag(parser);
continue;
}
perm = perm.intern();
ArraySet<String> perms = mSystemPermissions.get(uid);
if (perms == null) {
perms = new ArraySet<String>();
mSystemPermissions.put(uid, perms);
}
perms.add(perm);
XmlUtils.skipCurrentTag(parser);
} else if ("library".equals(name) && allowLibs) {
String lname = parser.getAttributeValue(null, "name");
String lfile = parser.getAttributeValue(null, "file");
if (lname == null) {
Slog.w(TAG, "<library> without name in " + permFile + " at "
+ parser.getPositionDescription());
} else if (lfile == null) {
Slog.w(TAG, "<library> without file in " + permFile + " at "
+ parser.getPositionDescription());
} else {
//Log.i(TAG, "Got library " + lname + " in " + lfile);
mSharedLibraries.put(lname, lfile);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("feature".equals(name) && allowFeatures) {
String fname = parser.getAttributeValue(null, "name");
int fversion = XmlUtils.readIntAttribute(parser, "version", 0);
boolean allowed;
if (!lowRam) {
allowed = true;
} else {
String notLowRam = parser.getAttributeValue(null, "notLowRam");
allowed = !"true".equals(notLowRam);
}
if (fname == null) {
Slog.w(TAG, "<feature> without name in " + permFile + " at "
+ parser.getPositionDescription());
} else if (allowed) {
addFeature(fname, fversion);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("unavailable-feature".equals(name) && allowFeatures) {
String fname = parser.getAttributeValue(null, "name");
if (fname == null) {
Slog.w(TAG, "<unavailable-feature> without name in " + permFile + " at "
+ parser.getPositionDescription());
} else {
mUnavailableFeatures.add(fname);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("allow-in-power-save-except-idle".equals(name) && allowAll) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<allow-in-power-save-except-idle> without package in "
+ permFile + " at " + parser.getPositionDescription());
} else {
mAllowInPowerSaveExceptIdle.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("allow-in-power-save".equals(name) && allowAll) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<allow-in-power-save> without package in " + permFile + " at "
+ parser.getPositionDescription());
} else {
mAllowInPowerSave.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("allow-in-data-usage-save".equals(name) && allowAll) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<allow-in-data-usage-save> without package in " + permFile
+ " at " + parser.getPositionDescription());
} else {
mAllowInDataUsageSave.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("allow-unthrottled-location".equals(name) && allowAll) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<allow-unthrottled-location> without package in "
+ permFile + " at " + parser.getPositionDescription());
} else {
mAllowUnthrottledLocation.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("allow-implicit-broadcast".equals(name) && allowAll) {
String action = parser.getAttributeValue(null, "action");
if (action == null) {
Slog.w(TAG, "<allow-implicit-broadcast> without action in " + permFile
+ " at " + parser.getPositionDescription());
} else {
mAllowImplicitBroadcasts.add(action);
}
XmlUtils.skipCurrentTag(parser);
continue;
} else if ("app-link".equals(name) && allowAppConfigs) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<app-link> without package in " + permFile + " at "
+ parser.getPositionDescription());
} else {
mLinkedApps.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
} else if ("system-user-whitelisted-app".equals(name) && allowAppConfigs) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<system-user-whitelisted-app> without package in " + permFile
+ " at " + parser.getPositionDescription());
} else {
mSystemUserWhitelistedApps.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
} else if ("system-user-blacklisted-app".equals(name) && allowAppConfigs) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<system-user-blacklisted-app without package in " + permFile
+ " at " + parser.getPositionDescription());
} else {
mSystemUserBlacklistedApps.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
} else if ("default-enabled-vr-app".equals(name) && allowAppConfigs) {
String pkgname = parser.getAttributeValue(null, "package");
String clsname = parser.getAttributeValue(null, "class");
if (pkgname == null) {
Slog.w(TAG, "<default-enabled-vr-app without package in " + permFile
+ " at " + parser.getPositionDescription());
} else if (clsname == null) {
Slog.w(TAG, "<default-enabled-vr-app without class in " + permFile
+ " at " + parser.getPositionDescription());
} else {
mDefaultVrComponents.add(new ComponentName(pkgname, clsname));
}
XmlUtils.skipCurrentTag(parser);
} else if ("backup-transport-whitelisted-service".equals(name) && allowFeatures) {
String serviceName = parser.getAttributeValue(null, "service");
if (serviceName == null) {
Slog.w(TAG, "<backup-transport-whitelisted-service> without service in "
+ permFile + " at " + parser.getPositionDescription());
} else {
ComponentName cn = ComponentName.unflattenFromString(serviceName);
if (cn == null) {
Slog.w(TAG,
"<backup-transport-whitelisted-service> with invalid service name "
+ serviceName + " in "+ permFile
+ " at " + parser.getPositionDescription());
} else {
mBackupTransportWhitelist.add(cn);
}
}
XmlUtils.skipCurrentTag(parser);
} else if ("disabled-until-used-preinstalled-carrier-associated-app".equals(name)
&& allowAppConfigs) {
String pkgname = parser.getAttributeValue(null, "package");
String carrierPkgname = parser.getAttributeValue(null, "carrierAppPackage");
if (pkgname == null || carrierPkgname == null) {
Slog.w(TAG, "<disabled-until-used-preinstalled-carrier-associated-app"
+ " without package or carrierAppPackage in " + permFile + " at "
+ parser.getPositionDescription());
} else {
List<String> associatedPkgs =
mDisabledUntilUsedPreinstalledCarrierAssociatedApps.get(
carrierPkgname);
if (associatedPkgs == null) {
associatedPkgs = new ArrayList<>();
mDisabledUntilUsedPreinstalledCarrierAssociatedApps.put(
carrierPkgname, associatedPkgs);
}
associatedPkgs.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
} else if ("privapp-permissions".equals(name) && allowPrivappPermissions) {
readPrivAppPermissions(parser);
} else if ("hidden-api-whitelisted-app".equals(name) && allowApiWhitelisting) {
String pkgname = parser.getAttributeValue(null, "package");
if (pkgname == null) {
Slog.w(TAG, "<hidden-api-whitelisted-app> without package in " + permFile
+ " at " + parser.getPositionDescription());
} else {
mHiddenApiPackageWhitelist.add(pkgname);
}
XmlUtils.skipCurrentTag(parser);
} else {
XmlUtils.skipCurrentTag(parser);
continue;
}
}
} catch (XmlPullParserException e) {
Slog.w(TAG, "Got exception parsing permissions.", e);
} catch (IOException e) {
Slog.w(TAG, "Got exception parsing permissions.", e);
} finally {
IoUtils.closeQuietly(permReader);
}
// Some devices can be field-converted to FBE, so offer to splice in
// those features if not already defined by the static config
if (StorageManager.isFileEncryptedNativeOnly()) {
addFeature(PackageManager.FEATURE_FILE_BASED_ENCRYPTION, 0);
addFeature(PackageManager.FEATURE_SECURELY_REMOVES_USERS, 0);
}
if (ActivityManager.isLowRamDeviceStatic()) {
addFeature(PackageManager.FEATURE_RAM_LOW, 0);
} else {
addFeature(PackageManager.FEATURE_RAM_NORMAL, 0);
}
for (String featureName : mUnavailableFeatures) {
removeFeature(featureName);
}
}
private void addFeature(String name, int version) {
FeatureInfo fi = mAvailableFeatures.get(name);
if (fi == null) {
fi = new FeatureInfo();
fi.name = name;
fi.version = version;
mAvailableFeatures.put(name, fi);
} else {
fi.version = Math.max(fi.version, version);
}
}
private void removeFeature(String name) {
if (mAvailableFeatures.remove(name) != null) {
Slog.d(TAG, "Removed unavailable feature " + name);
}
}
void readPermission(XmlPullParser parser, String name)
throws IOException, XmlPullParserException {
if (mPermissions.containsKey(name)) {
throw new IllegalStateException("Duplicate permission definition for " + name);
}
final boolean perUser = XmlUtils.readBooleanAttribute(parser, "perUser", false);
final PermissionEntry perm = new PermissionEntry(name, perUser);
mPermissions.put(name, perm);
int outerDepth = parser.getDepth();
int type;
while ((type=parser.next()) != XmlPullParser.END_DOCUMENT
&& (type != XmlPullParser.END_TAG
|| parser.getDepth() > outerDepth)) {
if (type == XmlPullParser.END_TAG
|| type == XmlPullParser.TEXT) {
continue;
}
String tagName = parser.getName();
if ("group".equals(tagName)) {
String gidStr = parser.getAttributeValue(null, "gid");
if (gidStr != null) {
int gid = Process.getGidForName(gidStr);
perm.gids = appendInt(perm.gids, gid);
} else {
Slog.w(TAG, "<group> without gid at "
+ parser.getPositionDescription());
}
}
XmlUtils.skipCurrentTag(parser);
}
}
5. 總結
整篇博客其實對platform.xml的分析還是比較膚淺的，<allow-in-power-save>瞭解的稍微好一點，後續接着對應的系統調用看下配置各項屬性真正的作用纔算真正的對這個xml有所瞭解吧。