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/*
* Copyright (C) 2016 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "linker_logger.h"
#include <string.h>
#include <sys/prctl.h>
#include <unistd.h>
#include <string>
#include <vector>
#include <async_safe/log.h>
#include "android-base/strings.h"
#include "private/CachedProperty.h"
LinkerLogger g_linker_logger;
bool g_greylist_disabled = false;
static uint32_t ParseProperty(const std::string& value) {
if (value.empty()) {
return 0;
}
std::vector<std::string> options = android::base::Split(value, ",");
uint32_t flags = 0;
for (const auto& o : options) {
if (o == "dlerror") {
flags |= kLogErrors;
} else if (o == "dlopen") {
flags |= kLogDlopen;
} else if (o == "dlsym") {
flags |= kLogDlsym;
} else {
async_safe_format_log(ANDROID_LOG_WARN, "linker", "Ignoring unknown debug.ld option \"%s\"",
o.c_str());
}
}
return flags;
}
static void GetAppSpecificProperty(char* buffer) {
// Get process basename.
const char* process_name_start = basename(g_argv[0]);
// Remove ':' and everything after it. This is the naming convention for
// services: https://developer.android.com/guide/components/services.html
const char* process_name_end = strchr(process_name_start, ':');
std::string process_name = (process_name_end != nullptr) ?
std::string(process_name_start, (process_name_end - process_name_start)) :
std::string(process_name_start);
std::string property_name = std::string("debug.ld.app.") + process_name;
__system_property_get(property_name.c_str(), buffer);
}
void LinkerLogger::ResetState() {
// The most likely scenario app is not debuggable and
// is running on a user build, in which case logging is disabled.
if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0) {
return;
}
// This is a convenient place to check whether the greylist should be disabled for testing.
static CachedProperty greylist_disabled("debug.ld.greylist_disabled");
bool old_value = g_greylist_disabled;
g_greylist_disabled = (strcmp(greylist_disabled.Get(), "true") == 0);
if (g_greylist_disabled != old_value) {
async_safe_format_log(ANDROID_LOG_INFO, "linker", "%s greylist",
g_greylist_disabled ? "Disabling" : "Enabling");
}
flags_ = 0;
// For logging, check the flag applied to all processes first.
static CachedProperty debug_ld_all("debug.ld.all");
flags_ |= ParseProperty(debug_ld_all.Get());
// Safeguard against a NULL g_argv. Ignore processes started without argv (http://b/33276926).
if (g_argv == nullptr || g_argv[0] == nullptr) {
return;
}
// Otherwise check the app-specific property too.
// We can't easily cache the property here because argv[0] changes.
char debug_ld_app[PROP_VALUE_MAX] = {};
GetAppSpecificProperty(debug_ld_app);
flags_ |= ParseProperty(debug_ld_app);
}
void LinkerLogger::Log(uint32_t type, const char* format, ...) {
if ((flags_ & type) == 0) {
return;
}
va_list ap;
va_start(ap, format);
async_safe_format_log_va_list(ANDROID_LOG_DEBUG, "linker", format, ap);
va_end(ap);
}
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