EGL renderer override: use symlinks instead of properties to specify overrides.

This fixes the character limit on app names, and reduces risk of privacy leaks.
This commit is contained in:
JeremyRand 2019-08-15 21:04:28 +02:00 committed by Joonas Kylmälä
parent d145013da2
commit 1346c0d7f5
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GPG Key ID: 132DEBCE65522635
1 changed files with 27 additions and 33 deletions

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@ -125,14 +125,11 @@ static char const * getProcessCmdline() {
* Used when running multiple (usually software) renderers on a single device. * Used when running multiple (usually software) renderers on a single device.
* Requires ro.zygote.disable_gl_preload to be enabled! * Requires ro.zygote.disable_gl_preload to be enabled!
* *
* It looks for these properties in this preferred order: * It looks for libraries in the filesystem in this preferred order:
* persist.egl._uid_<application UID> * /data/data/<application name>/os_override/libGLES_impl.so
* persist.egl.<application name> (limited to 31 characters in length) * /system/etc/os_override/<application name>/libGLES_impl.so
* *
* The UID is prefered since it works with multiple users or long names. * Usually, libGLES.so would be a symlink to a GLES implementation.
* Using the application name is useful for shipping pre-configured setups.
*
* The property value can either be a search path or a single GLES library.
* *
* MatchFile::find() does the heavy lifting of using the value. * MatchFile::find() does the heavy lifting of using the value.
* As of writing it searches for the value '/system/lib/libGLES_mesa.so' * As of writing it searches for the value '/system/lib/libGLES_mesa.so'
@ -149,26 +146,32 @@ static char* getOverridePath(void) {
// otherwise overrides only happen once, to zygote // otherwise overrides only happen once, to zygote
if (!property_get_bool("ro.zygote.disable_gl_preload", 0)) { if (!property_get_bool("ro.zygote.disable_gl_preload", 0)) {
ALOGD("ro.zygote.disable_gl_preload not set," ALOGD("ro.zygote.disable_gl_preload not set,"
" persist.egl.* overrides disabled"); " EGL overrides disabled");
return 0; return 0;
} }
static char prop[PROPERTY_VALUE_MAX]; String8 data_override_path("/data/data/");
String8 prop_prefix("persist.egl."); data_override_path.appendFormat("%s", getProcessCmdline());
String8 prop_uid(prop_prefix); data_override_path.appendFormat("%s", "/os_override/libGLES_impl.so");
String8 prop_name(prop_prefix);
prop_uid.appendFormat("_uid_%i", getuid());
prop_name.appendFormat("%s", getProcessCmdline());
char* prop_name_trunc = prop_name.lockBuffer(PROPERTY_KEY_MAX);
prop_name_trunc[PROPERTY_KEY_MAX - 1] = '\0';
ALOGD("checking %s then %s for overrides...", ALOGD("checking %s for override...",
prop_uid.string(), prop_name_trunc); data_override_path.string());
if (property_get(prop_uid.string(),prop,NULL) || if (access( data_override_path.string(), R_OK ) ) {
property_get(prop_name_trunc,prop,NULL)) { ALOGD("override found: %s", data_override_path.string());
ALOGD("override found: %s", prop); return data_override_path.string();
return prop; }
String8 system_override_path("/system/etc/os_override/");
system_override_path.appendFormat("%s", getProcessCmdline());
system_override_path.appendFormat("%s", "/libGLES_impl.so");
ALOGD("checking %s for override...",
system_override_path.string());
if (access( system_override_path.string(), R_OK ) ) {
ALOGD("override found: %s", system_override_path.string());
return system_override_path.string();
} }
ALOGD("no override found"); ALOGD("no override found");
@ -340,17 +343,8 @@ void *Loader::load_driver(const char* kind,
// check for overrides first // check for overrides first
char* overridePath = getOverridePath(); char* overridePath = getOverridePath();
if (overridePath) { if (overridePath) {
// search the path in case its a directory result.setTo(overridePath);
// this ignores the software renderer return result;
if (search_path(kind, overridePath, result)) {
return result;
} else if (!access(overridePath, R_OK)) {
// not a directory but accessible so probably a file?
result.setTo(overridePath);
return result;
} else {
ALOGD("override not a file or search path, ignoring...");
}
} }
// in the emulator case, we just return the hardcoded name // in the emulator case, we just return the hardcoded name