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/*
* Copyright (C) 2017 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_config.h"
#include "linker_globals.h"
#include "linker_debug.h"
#include "linker_utils.h"
#include <android-base/file.h>
#include <android-base/properties.h>
#include <android-base/scopeguard.h>
#include <android-base/strings.h>
#include <async_safe/log.h>
#include <limits.h>
#include <stdlib.h>
#include <unistd.h>
#include <string>
#include <unordered_map>
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>
class ConfigParser {
public:
enum {
kPropertyAssign,
kPropertyAppend,
kSection,
kEndOfFile,
kError,
};
explicit ConfigParser(std::string&& content)
: content_(std::move(content)), p_(0), lineno_(0), was_end_of_file_(false) {}
/*
* Possible return values
* kPropertyAssign: name is set to property name and value is set to property value
* kPropertyAppend: same as kPropertyAssign, but the value should be appended
* kSection: name is set to section name.
* kEndOfFile: reached end of file.
* kError: error_msg is set.
*/
int next_token(std::string* name, std::string* value, std::string* error_msg) {
std::string line;
while(NextLine(&line)) {
size_t found = line.find('#');
line = android::base::Trim(line.substr(0, found));
if (line.empty()) {
continue;
}
if (line[0] == '[' && line.back() == ']') {
*name = line.substr(1, line.size() - 2);
return kSection;
}
size_t found_assign = line.find('=');
size_t found_append = line.find("+=");
if (found_assign != std::string::npos && found_append == std::string::npos) {
*name = android::base::Trim(line.substr(0, found_assign));
*value = android::base::Trim(line.substr(found_assign + 1));
return kPropertyAssign;
}
if (found_append != std::string::npos) {
*name = android::base::Trim(line.substr(0, found_append));
*value = android::base::Trim(line.substr(found_append + 2));
return kPropertyAppend;
}
*error_msg = std::string("invalid format: ") +
line +
", expected \"name = property\", \"name += property\", or \"[section]\"";
return kError;
}
// to avoid infinite cycles when programmer makes a mistake
CHECK(!was_end_of_file_);
was_end_of_file_ = true;
return kEndOfFile;
}
size_t lineno() const {
return lineno_;
}
private:
bool NextLine(std::string* line) {
if (p_ == std::string::npos) {
return false;
}
size_t found = content_.find('\n', p_);
if (found != std::string::npos) {
*line = content_.substr(p_, found - p_);
p_ = found + 1;
} else {
*line = content_.substr(p_);
p_ = std::string::npos;
}
lineno_++;
return true;
}
std::string content_;
size_t p_;
size_t lineno_;
bool was_end_of_file_;
DISALLOW_IMPLICIT_CONSTRUCTORS(ConfigParser);
};
class PropertyValue {
public:
PropertyValue() = default;
PropertyValue(std::string&& value, size_t lineno)
: value_(std::move(value)), lineno_(lineno) {}
const std::string& value() const {
return value_;
}
void append_value(std::string&& value) {
value_ = value_ + value;
// lineno isn't updated as we might have cases like this:
// property.x = blah
// property.y = blah
// property.x += blah
}
size_t lineno() const {
return lineno_;
}
private:
std::string value_;
size_t lineno_;
};
static std::string create_error_msg(const char* file,
size_t lineno,
const std::string& msg) {
char buf[1024];
async_safe_format_buffer(buf, sizeof(buf), "%s:%zu: error: %s", file, lineno, msg.c_str());
return std::string(buf);
}
static bool parse_config_file(const char* ld_config_file_path,
const char* binary_realpath,
std::unordered_map<std::string, PropertyValue>* properties,
std::string* error_msg) {
std::string content;
if (!android::base::ReadFileToString(ld_config_file_path, &content)) {
if (errno != ENOENT) {
*error_msg = std::string("error reading file \"") +
ld_config_file_path + "\": " + strerror(errno);
}
return false;
}
ConfigParser cp(std::move(content));
std::string section_name;
while (true) {
std::string name;
std::string value;
std::string error;
int result = cp.next_token(&name, &value, &error);
if (result == ConfigParser::kError) {
DL_WARN("%s:%zd: warning: couldn't parse %s (ignoring this line)",
ld_config_file_path,
cp.lineno(),
error.c_str());
continue;
}
if (result == ConfigParser::kSection || result == ConfigParser::kEndOfFile) {
return false;
}
if (result == ConfigParser::kPropertyAssign) {
if (!android::base::StartsWith(name, "dir.")) {
DL_WARN("%s:%zd: warning: unexpected property name \"%s\", "
"expected format dir.<section_name> (ignoring this line)",
ld_config_file_path,
cp.lineno(),
name.c_str());
continue;
}
// remove trailing '/'
while (!value.empty() && value.back() == '/') {
value.pop_back();
}
if (value.empty()) {
DL_WARN("%s:%zd: warning: property value is empty (ignoring this line)",
ld_config_file_path,
cp.lineno());
continue;
}
// If the path can be resolved, resolve it
char buf[PATH_MAX];
std::string resolved_path;
if (access(value.c_str(), R_OK) != 0) {
if (errno == ENOENT) {
// no need to test for non-existing path. skip.
continue;
}
// If not accessible, don't call realpath as it will just cause
// SELinux denial spam. Use the path unresolved.
resolved_path = value;
} else if (realpath(value.c_str(), buf)) {
resolved_path = buf;
} else {
// realpath is expected to fail with EPERM in some situations, so log
// the failure with INFO rather than DL_WARN. e.g. A binary in
// /data/local/tmp may attempt to stat /postinstall. See
// http://b/120996057.
INFO("%s:%zd: warning: path \"%s\" couldn't be resolved: %s",
ld_config_file_path,
cp.lineno(),
value.c_str(),
strerror(errno));
resolved_path = value;
}
if (file_is_under_dir(binary_realpath, resolved_path)) {
section_name = name.substr(4);
break;
}
}
}
INFO("[ Using config section \"%s\" ]", section_name.c_str());
// skip everything until we meet a correct section
while (true) {
std::string name;
std::string value;
std::string error;
int result = cp.next_token(&name, &value, &error);
if (result == ConfigParser::kSection && name == section_name) {
break;
}
if (result == ConfigParser::kEndOfFile) {
*error_msg = create_error_msg(ld_config_file_path,
cp.lineno(),
std::string("section \"") + section_name + "\" not found");
return false;
}
}
// found the section - parse it
while (true) {
std::string name;
std::string value;
std::string error;
int result = cp.next_token(&name, &value, &error);
if (result == ConfigParser::kEndOfFile || result == ConfigParser::kSection) {
break;
}
if (result == ConfigParser::kPropertyAssign) {
if (properties->find(name) != properties->end()) {
DL_WARN("%s:%zd: warning: redefining property \"%s\" (overriding previous value)",
ld_config_file_path,
cp.lineno(),
name.c_str());
}
(*properties)[name] = PropertyValue(std::move(value), cp.lineno());
} else if (result == ConfigParser::kPropertyAppend) {
if (properties->find(name) == properties->end()) {
DL_WARN("%s:%zd: warning: appending to undefined property \"%s\" (treating as assignment)",
ld_config_file_path,
cp.lineno(),
name.c_str());
(*properties)[name] = PropertyValue(std::move(value), cp.lineno());
} else {
if (android::base::EndsWith(name, ".links") ||
android::base::EndsWith(name, ".namespaces")) {
value = "," + value;
(*properties)[name].append_value(std::move(value));
} else if (android::base::EndsWith(name, ".paths") ||
android::base::EndsWith(name, ".shared_libs") ||
android::base::EndsWith(name, ".whitelisted") ||
android::base::EndsWith(name, ".allowed_libs")) {
value = ":" + value;
(*properties)[name].append_value(std::move(value));
} else {
DL_WARN("%s:%zd: warning: += isn't allowed for property \"%s\" (ignoring)",
ld_config_file_path,
cp.lineno(),
name.c_str());
}
}
}
if (result == ConfigParser::kError) {
DL_WARN("%s:%zd: warning: couldn't parse %s (ignoring this line)",
ld_config_file_path,
cp.lineno(),
error.c_str());
continue;
}
}
return true;
}
static Config g_config;
static constexpr const char* kDefaultConfigName = "default";
static constexpr const char* kPropertyAdditionalNamespaces = "additional.namespaces";
class Properties {
public:
explicit Properties(std::unordered_map<std::string, PropertyValue>&& properties)
: properties_(std::move(properties)), target_sdk_version_(__ANDROID_API__) {}
std::vector<std::string> get_strings(const std::string& name, size_t* lineno = nullptr) const {
auto it = find_property(name, lineno);
if (it == properties_.end()) {
// return empty vector
return std::vector<std::string>();
}
std::vector<std::string> strings = android::base::Split(it->second.value(), ",");
for (size_t i = 0; i < strings.size(); ++i) {
strings[i] = android::base::Trim(strings[i]);
}
return strings;
}
bool get_bool(const std::string& name, size_t* lineno = nullptr) const {
auto it = find_property(name, lineno);
if (it == properties_.end()) {
return false;
}
return it->second.value() == "true";
}
std::string get_string(const std::string& name, size_t* lineno = nullptr) const {
auto it = find_property(name, lineno);
return (it == properties_.end()) ? "" : it->second.value();
}
std::vector<std::string> get_paths(const std::string& name, bool resolve, size_t* lineno = nullptr) {
std::string paths_str = get_string(name, lineno);
std::vector<std::string> paths;
split_path(paths_str.c_str(), ":", &paths);
std::vector<std::pair<std::string, std::string>> params;
params.push_back({ "LIB", kLibPath });
if (target_sdk_version_ != 0) {
char buf[16];
async_safe_format_buffer(buf, sizeof(buf), "%d", target_sdk_version_);
params.push_back({ "SDK_VER", buf });
}
static std::string vndk_ver = Config::get_vndk_version_string('-');
params.push_back({ "VNDK_VER", vndk_ver });
static std::string vndk_apex_ver = Config::get_vndk_version_string('v');
params.push_back({ "VNDK_APEX_VER", vndk_apex_ver });
for (auto& path : paths) {
format_string(&path, params);
}
if (resolve) {
std::vector<std::string> resolved_paths;
for (const auto& path : paths) {
if (path.empty()) {
continue;
}
// this is single threaded. no need to lock
auto cached = resolved_paths_.find(path);
if (cached == resolved_paths_.end()) {
resolved_paths_[path] = resolve_path(path);
cached = resolved_paths_.find(path);
}
CHECK(cached != resolved_paths_.end());
if (cached->second.empty()) {
continue;
}
resolved_paths.push_back(cached->second);
}
return resolved_paths;
} else {
return paths;
}
}
void set_target_sdk_version(int target_sdk_version) {
target_sdk_version_ = target_sdk_version;
}
private:
std::unordered_map<std::string, PropertyValue>::const_iterator
find_property(const std::string& name, size_t* lineno) const {
auto it = properties_.find(name);
if (it != properties_.end() && lineno != nullptr) {
*lineno = it->second.lineno();
}
return it;
}
std::unordered_map<std::string, PropertyValue> properties_;
std::unordered_map<std::string, std::string> resolved_paths_;
int target_sdk_version_;
DISALLOW_IMPLICIT_CONSTRUCTORS(Properties);
};
bool Config::read_binary_config(const char* ld_config_file_path,
const char* binary_realpath,
bool is_asan,
const Config** config,
std::string* error_msg) {
g_config.clear();
std::unordered_map<std::string, PropertyValue> property_map;
if (!parse_config_file(ld_config_file_path, binary_realpath, &property_map, error_msg)) {
return false;
}
Properties properties(std::move(property_map));
auto failure_guard = android::base::make_scope_guard([] { g_config.clear(); });
std::unordered_map<std::string, NamespaceConfig*> namespace_configs;
namespace_configs[kDefaultConfigName] = g_config.create_namespace_config(kDefaultConfigName);
std::vector<std::string> additional_namespaces = properties.get_strings(kPropertyAdditionalNamespaces);
for (const auto& name : additional_namespaces) {
namespace_configs[name] = g_config.create_namespace_config(name);
}
bool versioning_enabled = properties.get_bool("enable.target.sdk.version");
int target_sdk_version = __ANDROID_API__;
if (versioning_enabled) {
std::string version_file = dirname(binary_realpath) + "/.version";
std::string content;
if (!android::base::ReadFileToString(version_file, &content)) {
if (errno != ENOENT) {
*error_msg = std::string("error reading version file \"") +
version_file + "\": " + strerror(errno);
return false;
}
} else {
content = android::base::Trim(content);
errno = 0;
char* end = nullptr;
const char* content_str = content.c_str();
int result = strtol(content_str, &end, 10);
if (errno == 0 && *end == '\0' && result > 0) {
target_sdk_version = result;
properties.set_target_sdk_version(target_sdk_version);
} else {
*error_msg = std::string("invalid version \"") + version_file + "\": \"" + content +"\"";
return false;
}
}
}
g_config.set_target_sdk_version(target_sdk_version);
for (const auto& ns_config_it : namespace_configs) {
auto& name = ns_config_it.first;
NamespaceConfig* ns_config = ns_config_it.second;
std::string property_name_prefix = std::string("namespace.") + name;
size_t lineno = 0;
std::vector<std::string> linked_namespaces =
properties.get_strings(property_name_prefix + ".links", &lineno);
for (const auto& linked_ns_name : linked_namespaces) {
if (namespace_configs.find(linked_ns_name) == namespace_configs.end()) {
*error_msg = create_error_msg(ld_config_file_path,
lineno,
std::string("undefined namespace: ") + linked_ns_name);
return false;
}
bool allow_all_shared_libs = properties.get_bool(property_name_prefix + ".link." +
linked_ns_name + ".allow_all_shared_libs");
std::string shared_libs = properties.get_string(property_name_prefix +
".link." +
linked_ns_name +
".shared_libs", &lineno);
if (!allow_all_shared_libs && shared_libs.empty()) {
*error_msg = create_error_msg(ld_config_file_path,
lineno,
std::string("list of shared_libs for ") +
name +
"->" +
linked_ns_name +
" link is not specified or is empty.");
return false;
}
if (allow_all_shared_libs && !shared_libs.empty()) {
*error_msg = create_error_msg(ld_config_file_path, lineno,
std::string("both shared_libs and allow_all_shared_libs "
"are set for ") +
name + "->" + linked_ns_name + " link.");
return false;
}
ns_config->add_namespace_link(linked_ns_name, shared_libs, allow_all_shared_libs);
}
ns_config->set_isolated(properties.get_bool(property_name_prefix + ".isolated"));
ns_config->set_visible(properties.get_bool(property_name_prefix + ".visible"));
std::string allowed_libs =
properties.get_string(property_name_prefix + ".whitelisted", &lineno);
const std::string libs = properties.get_string(property_name_prefix + ".allowed_libs", &lineno);
if (!allowed_libs.empty() && !libs.empty()) {
allowed_libs += ":";
}
allowed_libs += libs;
if (!allowed_libs.empty()) {
ns_config->set_allowed_libs(android::base::Split(allowed_libs, ":"));
}
// these are affected by is_asan flag
if (is_asan) {
property_name_prefix += ".asan";
}
// search paths are resolved (canonicalized). This is required mainly for
// the case when /vendor is a symlink to /system/vendor, which is true for
// non Treble-ized legacy devices.
ns_config->set_search_paths(properties.get_paths(property_name_prefix + ".search.paths", true));
// However, for permitted paths, we are not required to resolve the paths
// since they are only set for isolated namespaces, which implies the device
// is Treble-ized (= /vendor is not a symlink to /system/vendor).
// In fact, the resolving is causing an unexpected side effect of selinux
// denials on some executables which are not allowed to access some of the
// permitted paths.
ns_config->set_permitted_paths(properties.get_paths(property_name_prefix + ".permitted.paths", false));
}
failure_guard.Disable();
*config = &g_config;
return true;
}
std::string Config::get_vndk_version_string(const char delimiter) {
std::string version = android::base::GetProperty("ro.vndk.version", "");
if (version != "" && version != "current") {
//add the delimiter char in front of the string and return it.
return version.insert(0, 1, delimiter);
}
return "";
}
NamespaceConfig* Config::create_namespace_config(const std::string& name) {
namespace_configs_.push_back(std::unique_ptr<NamespaceConfig>(new NamespaceConfig(name)));
NamespaceConfig* ns_config_ptr = namespace_configs_.back().get();
namespace_configs_map_[name] = ns_config_ptr;
return ns_config_ptr;
}
void Config::clear() {
namespace_configs_.clear();
namespace_configs_map_.clear();
}