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| 1 | +/* |
| 2 | + * Copyright (C) 2018 The Android Open Source Project |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +#include "modalias_handler.h" |
| 18 | + |
| 19 | +#include <fnmatch.h> |
| 20 | +#include <sys/syscall.h> |
| 21 | + |
| 22 | +#include <algorithm> |
| 23 | +#include <functional> |
| 24 | +#include <string> |
| 25 | +#include <vector> |
| 26 | + |
| 27 | +#include <android-base/chrono_utils.h> |
| 28 | +#include <android-base/logging.h> |
| 29 | +#include <android-base/unique_fd.h> |
| 30 | + |
| 31 | +#include "parser.h" |
| 32 | + |
| 33 | +namespace android { |
| 34 | +namespace init { |
| 35 | + |
| 36 | +Result<Success> ModaliasHandler::ParseDepCallback(std::vector<std::string>&& args) { |
| 37 | + std::vector<std::string> deps; |
| 38 | + |
| 39 | + // Set first item as our modules path |
| 40 | + std::string::size_type pos = args[0].find(':'); |
| 41 | + if (pos != std::string::npos) { |
| 42 | + deps.emplace_back(args[0].substr(0, pos)); |
| 43 | + } else { |
| 44 | + return Error() << "dependency lines must start with name followed by ':'"; |
| 45 | + } |
| 46 | + |
| 47 | + // Remaining items are dependencies of our module |
| 48 | + for (auto arg = args.begin() + 1; arg != args.end(); ++arg) { |
| 49 | + deps.push_back(*arg); |
| 50 | + } |
| 51 | + |
| 52 | + // Key is striped module name to match names in alias file |
| 53 | + std::size_t start = args[0].find_last_of("/"); |
| 54 | + std::size_t end = args[0].find(".ko:"); |
| 55 | + if ((end - start) <= 1) return Error() << "malformed dependency line"; |
| 56 | + auto mod_name = args[0].substr(start + 1, (end - start) - 1); |
| 57 | + // module names can have '-', but their file names will have '_' |
| 58 | + std::replace(mod_name.begin(), mod_name.end(), '-', '_'); |
| 59 | + this->module_deps_[mod_name] = deps; |
| 60 | + |
| 61 | + return Success(); |
| 62 | +} |
| 63 | + |
| 64 | +Result<Success> ModaliasHandler::ParseAliasCallback(std::vector<std::string>&& args) { |
| 65 | + auto it = args.begin(); |
| 66 | + const std::string& type = *it++; |
| 67 | + |
| 68 | + if (type != "alias") { |
| 69 | + return Error() << "we only handle alias lines, got: " << type; |
| 70 | + } |
| 71 | + |
| 72 | + if (args.size() != 3) { |
| 73 | + return Error() << "alias lines must have 3 entries"; |
| 74 | + } |
| 75 | + |
| 76 | + std::string& alias = *it++; |
| 77 | + std::string& module_name = *it++; |
| 78 | + this->module_aliases_.emplace_back(alias, module_name); |
| 79 | + |
| 80 | + return Success(); |
| 81 | +} |
| 82 | + |
| 83 | +ModaliasHandler::ModaliasHandler() { |
| 84 | + using namespace std::placeholders; |
| 85 | + |
| 86 | + static const std::string base_paths[] = { |
| 87 | + "/vendor/lib/modules/", |
| 88 | + "/lib/modules/", |
| 89 | + "/odm/lib/modules/", |
| 90 | + }; |
| 91 | + |
| 92 | + Parser alias_parser; |
| 93 | + auto alias_callback = std::bind(&ModaliasHandler::ParseAliasCallback, this, _1); |
| 94 | + alias_parser.AddSingleLineParser("alias", alias_callback); |
| 95 | + for (const auto& base_path : base_paths) alias_parser.ParseConfig(base_path + "modules.alias"); |
| 96 | + |
| 97 | + Parser dep_parser; |
| 98 | + auto dep_callback = std::bind(&ModaliasHandler::ParseDepCallback, this, _1); |
| 99 | + dep_parser.AddSingleLineParser("", dep_callback); |
| 100 | + for (const auto& base_path : base_paths) dep_parser.ParseConfig(base_path + "modules.dep"); |
| 101 | +} |
| 102 | + |
| 103 | +Result<Success> ModaliasHandler::Insmod(const std::string& path_name, const std::string& args) { |
| 104 | + base::unique_fd fd( |
| 105 | + TEMP_FAILURE_RETRY(open(path_name.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC))); |
| 106 | + if (fd == -1) return ErrnoError() << "Could not open module '" << path_name << "'"; |
| 107 | + |
| 108 | + int ret = syscall(__NR_finit_module, fd.get(), args.c_str(), 0); |
| 109 | + if (ret != 0) { |
| 110 | + if (errno == EEXIST) { |
| 111 | + // Module already loaded |
| 112 | + return Success(); |
| 113 | + } |
| 114 | + return ErrnoError() << "Failed to insmod '" << path_name << "' with args '" << args << "'"; |
| 115 | + } |
| 116 | + |
| 117 | + LOG(INFO) << "Loaded kernel module " << path_name; |
| 118 | + return Success(); |
| 119 | +} |
| 120 | + |
| 121 | +Result<Success> ModaliasHandler::InsmodWithDeps(const std::string& module_name, |
| 122 | + const std::string& args) { |
| 123 | + if (module_name.empty()) { |
| 124 | + return Error() << "Need valid module name"; |
| 125 | + } |
| 126 | + |
| 127 | + auto it = module_deps_.find(module_name); |
| 128 | + if (it == module_deps_.end()) { |
| 129 | + return Error() << "Module '" << module_name << "' not in dependency file"; |
| 130 | + } |
| 131 | + auto& dependencies = it->second; |
| 132 | + |
| 133 | + // load module dependencies in reverse order |
| 134 | + for (auto dep = dependencies.rbegin(); dep != dependencies.rend() - 1; ++dep) { |
| 135 | + if (auto result = Insmod(*dep, ""); !result) return result; |
| 136 | + } |
| 137 | + |
| 138 | + // load target module itself with args |
| 139 | + return Insmod(dependencies[0], args); |
| 140 | +} |
| 141 | + |
| 142 | +void ModaliasHandler::HandleModaliasEvent(const Uevent& uevent) { |
| 143 | + if (uevent.modalias.empty()) return; |
| 144 | + |
| 145 | + for (const auto& [alias, module] : module_aliases_) { |
| 146 | + if (fnmatch(alias.c_str(), uevent.modalias.c_str(), 0) != 0) continue; // Keep looking |
| 147 | + |
| 148 | + LOG(DEBUG) << "Loading kernel module '" << module << "' for alias '" << uevent.modalias |
| 149 | + << "'"; |
| 150 | + |
| 151 | + if (auto result = InsmodWithDeps(module, ""); !result) { |
| 152 | + LOG(ERROR) << "Cannot load module: " << result.error(); |
| 153 | + // try another one since there may be another match |
| 154 | + continue; |
| 155 | + } |
| 156 | + |
| 157 | + // loading was successful |
| 158 | + return; |
| 159 | + } |
| 160 | +} |
| 161 | + |
| 162 | +} // namespace init |
| 163 | +} // namespace android |
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