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/*
* 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 "common/libs/utils/users.h"
#include <cerrno>
#include <cstring>
#include <sys/types.h>
#include <unistd.h>
#include <grp.h>
#include <algorithm>
#include <vector>
#include <android-base/logging.h>
namespace {
gid_t GroupIdFromName(const std::string& group_name) {
struct group grp{};
struct group* grp_p{};
std::vector<char> buffer(100);
int result = 0;
while(true) {
result = getgrnam_r(group_name.c_str(), &grp, buffer.data(), buffer.size(),
&grp_p);
if (result != ERANGE) {
break;
}
buffer.resize(2*buffer.size());
}
if (result == 0) {
if (grp_p != nullptr) {
return grp.gr_gid;
} else {
LOG(ERROR) << "Group " << group_name << " does not exist";
return -1;
}
} else {
LOG(ERROR) << "Unable to get group id for group " << group_name << ": "
<< std::strerror(result);
return -1;
}
}
std::vector<gid_t> GetSuplementaryGroups() {
int num_groups = getgroups(0, nullptr);
if (num_groups < 0) {
LOG(ERROR) << "Unable to get number of suplementary groups: "
<< std::strerror(errno);
return {};
}
std::vector<gid_t> groups(num_groups + 1);
int retval = getgroups(groups.size(), groups.data());
if (retval < 0) {
LOG(ERROR) << "Error obtaining list of suplementary groups (list size: "
<< groups.size() << "): " << std::strerror(errno);
return {};
}
return groups;
}
} // namespace
bool cvd::InGroup(const std::string& group) {
auto gid = GroupIdFromName(group);
if (gid == static_cast<gid_t>(-1)) {
return false;
}
if (gid == getegid()) {
return true;
}
auto groups = GetSuplementaryGroups();
if (std::find(groups.cbegin(), groups.cend(), gid) != groups.cend()) {
return true;
}
return false;
}
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