platform_system_core/libmodprobe/libmodprobe_ext.cpp
Steve Muckle 8bafa9e28e add libmodprobe api to query the number of modules loaded
In the short term this will be used to help implement support for
multiple kernel module directories but it may be useful in other
contexts as well.

Bug: 157645635
Change-Id: I15a252b6e9394292c8f3557ed65112c935830441
Merged-In: I15a252b6e9394292c8f3557ed65112c935830441
2020-06-03 12:11:15 -07:00

101 lines
3.3 KiB
C++

/*
* Copyright (C) 2018 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.
*/
#include <sys/stat.h>
#include <sys/syscall.h>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/unique_fd.h>
#include <modprobe/modprobe.h>
std::string Modprobe::GetKernelCmdline(void) {
std::string cmdline;
if (!android::base::ReadFileToString("/proc/cmdline", &cmdline)) {
return "";
}
return cmdline;
}
bool Modprobe::Insmod(const std::string& path_name, const std::string& parameters) {
android::base::unique_fd fd(
TEMP_FAILURE_RETRY(open(path_name.c_str(), O_RDONLY | O_NOFOLLOW | O_CLOEXEC)));
if (fd == -1) {
LOG(ERROR) << "Could not open module '" << path_name << "'";
return false;
}
auto canonical_name = MakeCanonical(path_name);
std::string options = "";
auto options_iter = module_options_.find(canonical_name);
if (options_iter != module_options_.end()) {
options = options_iter->second;
}
if (!parameters.empty()) {
options = options + " " + parameters;
}
LOG(INFO) << "Loading module " << path_name << " with args \"" << options << "\"";
int ret = syscall(__NR_finit_module, fd.get(), options.c_str(), 0);
if (ret != 0) {
if (errno == EEXIST) {
// Module already loaded
module_loaded_.emplace(canonical_name);
return true;
}
LOG(ERROR) << "Failed to insmod '" << path_name << "' with args '" << options << "'";
return false;
}
LOG(INFO) << "Loaded kernel module " << path_name;
module_loaded_.emplace(canonical_name);
module_count_++;
return true;
}
bool Modprobe::Rmmod(const std::string& module_name) {
auto canonical_name = MakeCanonical(module_name);
int ret = syscall(__NR_delete_module, canonical_name.c_str(), O_NONBLOCK);
if (ret != 0) {
PLOG(ERROR) << "Failed to remove module '" << module_name << "'";
return false;
}
module_loaded_.erase(canonical_name);
return true;
}
bool Modprobe::ModuleExists(const std::string& module_name) {
struct stat fileStat;
if (blacklist_enabled && module_blacklist_.count(module_name)) {
LOG(INFO) << "module " << module_name << " is blacklisted";
return false;
}
auto deps = GetDependencies(module_name);
if (deps.empty()) {
// missing deps can happen in the case of an alias
return false;
}
if (stat(deps.front().c_str(), &fileStat)) {
LOG(INFO) << "module " << module_name << " does not exist";
return false;
}
if (!S_ISREG(fileStat.st_mode)) {
LOG(INFO) << "module " << module_name << " is not a regular file";
return false;
}
return true;
}