platform_system_vold/fs/Exfat.cpp
Paul Crowley de2d6201ab Refactor ForkExecvp to improve locking behaviour
Do our own fork/exec rather than using a library. This leads to
many improvements:

- unite the output recording path with the other path
- never concatenate arguments with spaces
- never use the shell
- move setexeccon after fork, so we don't need to take the lock
- general code refactor while we're there

My tests:
- Ensure Marlin device boots and vold_prepare_subdirs is called
successfully
- Try adb shell sm set-virtual-disk true, see that eg sgdisk output is
logged.

weilongping@huawei.com's tests:
- unlock a user's de and ce directory;
- connect to a OTG storage device or a sdcard and ensure the mount logic be successful

Bug: 26735063
Bug: 113796163
Test: details in commit
Change-Id: I0976413529d7cbeebf5b8649660a385f9b036f04
2018-12-06 09:37:02 -08:00

97 lines
2.7 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/mount.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <logwrap/logwrap.h>
#include "Exfat.h"
#include "Utils.h"
using android::base::StringPrintf;
namespace android {
namespace vold {
namespace exfat {
static const char* kMkfsPath = "/system/bin/mkfs.exfat";
static const char* kFsckPath = "/system/bin/fsck.exfat";
bool IsSupported() {
return access(kMkfsPath, X_OK) == 0 && access(kFsckPath, X_OK) == 0 &&
IsFilesystemSupported("exfat");
}
status_t Check(const std::string& source) {
std::vector<std::string> cmd;
cmd.push_back(kFsckPath);
cmd.push_back(source);
int rc = ForkExecvp(cmd, nullptr, sFsckUntrustedContext);
if (rc == 0) {
LOG(INFO) << "Check OK";
return 0;
} else {
LOG(ERROR) << "Check failed (code " << rc << ")";
errno = EIO;
return -1;
}
}
status_t Mount(const std::string& source, const std::string& target, int ownerUid, int ownerGid,
int permMask) {
int mountFlags = MS_NODEV | MS_NOSUID | MS_DIRSYNC | MS_NOATIME | MS_NOEXEC;
auto mountData = android::base::StringPrintf("uid=%d,gid=%d,fmask=%o,dmask=%o", ownerUid,
ownerGid, permMask, permMask);
if (mount(source.c_str(), target.c_str(), "exfat", mountFlags, mountData.c_str()) == 0) {
return 0;
}
PLOG(ERROR) << "Mount failed; attempting read-only";
mountFlags |= MS_RDONLY;
if (mount(source.c_str(), target.c_str(), "exfat", mountFlags, mountData.c_str()) == 0) {
return 0;
}
return -1;
}
status_t Format(const std::string& source) {
std::vector<std::string> cmd;
cmd.push_back(kMkfsPath);
cmd.push_back("-n");
cmd.push_back("android");
cmd.push_back(source);
int rc = ForkExecvp(cmd);
if (rc == 0) {
LOG(INFO) << "Format OK";
return 0;
} else {
LOG(ERROR) << "Format failed (code " << rc << ")";
errno = EIO;
return -1;
}
return 0;
}
} // namespace exfat
} // namespace vold
} // namespace android