/*
* Copyright (C) 2015 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 "Utils.h"
#include "Process.h"
#include "sehandle.h"
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/strings.h>
#include <android-base/stringprintf.h>
#include <cutils/fs.h>
#include <logwrap/logwrap.h>
#include <private/android_filesystem_config.h>
#include <mutex>
#include <dirent.h>
#include <fcntl.h>
#include <linux/fs.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/wait.h>
#include <sys/statvfs.h>
#ifndef UMOUNT_NOFOLLOW
#define UMOUNT_NOFOLLOW 0x00000008 /* Don't follow symlink on umount */
#endif
using android::base::ReadFileToString;
using android::base::StringPrintf;
namespace android {
namespace vold {
security_context_t sBlkidContext = nullptr;
security_context_t sBlkidUntrustedContext = nullptr;
security_context_t sFsckContext = nullptr;
security_context_t sFsckUntrustedContext = nullptr;
bool sSleepOnUnmount = true;
static const char* kBlkidPath = "/system/bin/blkid";
static const char* kKeyPath = "/data/misc/vold";
static const char* kProcFilesystems = "/proc/filesystems";
// Lock used to protect process-level SELinux changes from racing with each
// other between multiple threads.
static std::mutex kSecurityLock;
status_t CreateDeviceNode(const std::string& path, dev_t dev) {
std::lock_guard<std::mutex> lock(kSecurityLock);
const char* cpath = path.c_str();
status_t res = 0;
char* secontext = nullptr;
if (sehandle) {
if (!selabel_lookup(sehandle, &secontext, cpath, S_IFBLK)) {
setfscreatecon(secontext);
}
}
mode_t mode = 0660 | S_IFBLK;
if (mknod(cpath, mode, dev) < 0) {
if (errno != EEXIST) {
PLOG(ERROR) << "Failed to create device node for " << major(dev)
<< ":" << minor(dev) << " at " << path;
res = -errno;
}
}
if (secontext) {
setfscreatecon(nullptr);
freecon(secontext);
}
return res;
}
status_t DestroyDeviceNode(const std::string& path) {
const char* cpath = path.c_str();
if (TEMP_FAILURE_RETRY(unlink(cpath))) {
return -errno;
} else {
return OK;
}
}
status_t PrepareDir(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
std::lock_guard<std::mutex> lock(kSecurityLock);
const char* cpath = path.c_str();
char* secontext = nullptr;
if (sehandle) {
if (!selabel_lookup(sehandle, &secontext, cpath, S_IFDIR)) {
setfscreatecon(secontext);
}
}
int res = fs_prepare_dir(cpath, mode, uid, gid);
if (secontext) {
setfscreatecon(nullptr);
freecon(secontext);
}
if (res == 0) {
return OK;
} else {
return -errno;
}
}
status_t ForceUnmount(const std::string& path) {
const char* cpath = path.c_str();
if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
return OK;
}
// Apps might still be handling eject request, so wait before
// we start sending signals
if (sSleepOnUnmount) sleep(5);
KillProcessesWithOpenFiles(path, SIGINT);
if (sSleepOnUnmount) sleep(5);
if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
return OK;
}
KillProcessesWithOpenFiles(path, SIGTERM);
if (sSleepOnUnmount) sleep(5);
if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
return OK;
}
KillProcessesWithOpenFiles(path, SIGKILL);
if (sSleepOnUnmount) sleep(5);
if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
return OK;
}
return -errno;
}
status_t KillProcessesUsingPath(const std::string& path) {
if (KillProcessesWithOpenFiles(path, SIGINT) == 0) {
return OK;
}
if (sSleepOnUnmount) sleep(5);
if (KillProcessesWithOpenFiles(path, SIGTERM) == 0) {
return OK;
}
if (sSleepOnUnmount) sleep(5);
if (KillProcessesWithOpenFiles(path, SIGKILL) == 0) {
return OK;
}
if (sSleepOnUnmount) sleep(5);
// Send SIGKILL a second time to determine if we've
// actually killed everyone with open files
if (KillProcessesWithOpenFiles(path, SIGKILL) == 0) {
return OK;
}
PLOG(ERROR) << "Failed to kill processes using " << path;
return -EBUSY;
}
status_t BindMount(const std::string& source, const std::string& target) {
if (::mount(source.c_str(), target.c_str(), "", MS_BIND, NULL)) {
PLOG(ERROR) << "Failed to bind mount " << source << " to " << target;
return -errno;
}
return OK;
}
bool FindValue(const std::string& raw, const std::string& key, std::string* value) {
auto qual = key + "=\"";
auto start = raw.find(qual);
if (start > 0 && raw[start - 1] != ' ') {
start = raw.find(qual, start + 1);
}
if (start == std::string::npos) return false;
start += qual.length();
auto end = raw.find("\"", start);
if (end == std::string::npos) return false;
*value = raw.substr(start, end - start);
return true;
}
static status_t readMetadata(const std::string& path, std::string* fsType,
std::string* fsUuid, std::string* fsLabel, bool untrusted) {
fsType->clear();
fsUuid->clear();
fsLabel->clear();
std::vector<std::string> cmd;
cmd.push_back(kBlkidPath);
cmd.push_back("-c");
cmd.push_back("/dev/null");
cmd.push_back("-s");
cmd.push_back("TYPE");
cmd.push_back("-s");
cmd.push_back("UUID");
cmd.push_back("-s");
cmd.push_back("LABEL");
cmd.push_back(path);
std::vector<std::string> output;
status_t res = ForkExecvp(cmd, output, untrusted ? sBlkidUntrustedContext : sBlkidContext);
if (res != OK) {
LOG(WARNING) << "blkid failed to identify " << path;
return res;
}
for (const auto& line : output) {
// Extract values from blkid output, if defined
FindValue(line, "TYPE", fsType);
FindValue(line, "UUID", fsUuid);
FindValue(line, "LABEL", fsLabel);
}
return OK;
}
status_t ReadMetadata(const std::string& path, std::string* fsType,
std::string* fsUuid, std::string* fsLabel) {
return readMetadata(path, fsType, fsUuid, fsLabel, false);
}
status_t ReadMetadataUntrusted(const std::string& path, std::string* fsType,
std::string* fsUuid, std::string* fsLabel) {
return readMetadata(path, fsType, fsUuid, fsLabel, true);
}
status_t ForkExecvp(const std::vector<std::string>& args) {
return ForkExecvp(args, nullptr);
}
status_t ForkExecvp(const std::vector<std::string>& args, security_context_t context) {
std::lock_guard<std::mutex> lock(kSecurityLock);
size_t argc = args.size();
char** argv = (char**) calloc(argc, sizeof(char*));
for (size_t i = 0; i < argc; i++) {
argv[i] = (char*) args[i].c_str();
if (i == 0) {
LOG(VERBOSE) << args[i];
} else {
LOG(VERBOSE) << " " << args[i];
}
}
if (context) {
if (setexeccon(context)) {
LOG(ERROR) << "Failed to setexeccon";
abort();
}
}
status_t res = android_fork_execvp(argc, argv, NULL, false, true);
if (context) {
if (setexeccon(nullptr)) {
LOG(ERROR) << "Failed to setexeccon";
abort();
}
}
free(argv);
return res;
}
status_t ForkExecvp(const std::vector<std::string>& args,
std::vector<std::string>& output) {
return ForkExecvp(args, output, nullptr);
}
status_t ForkExecvp(const std::vector<std::string>& args,
std::vector<std::string>& output, security_context_t context) {
std::lock_guard<std::mutex> lock(kSecurityLock);
std::string cmd;
for (size_t i = 0; i < args.size(); i++) {
cmd += args[i] + " ";
if (i == 0) {
LOG(VERBOSE) << args[i];
} else {
LOG(VERBOSE) << " " << args[i];
}
}
output.clear();
if (context) {
if (setexeccon(context)) {
LOG(ERROR) << "Failed to setexeccon";
abort();
}
}
FILE* fp = popen(cmd.c_str(), "r"); // NOLINT
if (context) {
if (setexeccon(nullptr)) {
LOG(ERROR) << "Failed to setexeccon";
abort();
}
}
if (!fp) {
PLOG(ERROR) << "Failed to popen " << cmd;
return -errno;
}
char line[1024];
while (fgets(line, sizeof(line), fp) != nullptr) {
LOG(VERBOSE) << line;
output.push_back(std::string(line));
}
if (pclose(fp) != 0) {
PLOG(ERROR) << "Failed to pclose " << cmd;
return -errno;
}
return OK;
}
pid_t ForkExecvpAsync(const std::vector<std::string>& args) {
size_t argc = args.size();
char** argv = (char**) calloc(argc + 1, sizeof(char*));
for (size_t i = 0; i < argc; i++) {
argv[i] = (char*) args[i].c_str();
if (i == 0) {
LOG(VERBOSE) << args[i];
} else {
LOG(VERBOSE) << " " << args[i];
}
}
pid_t pid = fork();
if (pid == 0) {
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
if (execvp(argv[0], argv)) {
PLOG(ERROR) << "Failed to exec";
}
_exit(1);
}
if (pid == -1) {
PLOG(ERROR) << "Failed to exec";
}
free(argv);
return pid;
}
status_t ReadRandomBytes(size_t bytes, std::string& out) {
out.resize(bytes);
return ReadRandomBytes(bytes, &out[0]);
}
status_t ReadRandomBytes(size_t bytes, char* buf) {
int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
if (fd == -1) {
return -errno;
}
size_t n;
while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], bytes))) > 0) {
bytes -= n;
buf += n;
}
close(fd);
if (bytes == 0) {
return OK;
} else {
return -EIO;
}
}
status_t GenerateRandomUuid(std::string& out) {
status_t res = ReadRandomBytes(16, out);
if (res == OK) {
out[6] &= 0x0f; /* clear version */
out[6] |= 0x40; /* set to version 4 */
out[8] &= 0x3f; /* clear variant */
out[8] |= 0x80; /* set to IETF variant */
}
return res;
}
status_t HexToStr(const std::string& hex, std::string& str) {
str.clear();
bool even = true;
char cur = 0;
for (size_t i = 0; i < hex.size(); i++) {
int val = 0;
switch (hex[i]) {
case ' ': case '-': case ':': continue;
case 'f': case 'F': val = 15; break;
case 'e': case 'E': val = 14; break;
case 'd': case 'D': val = 13; break;
case 'c': case 'C': val = 12; break;
case 'b': case 'B': val = 11; break;
case 'a': case 'A': val = 10; break;
case '9': val = 9; break;
case '8': val = 8; break;
case '7': val = 7; break;
case '6': val = 6; break;
case '5': val = 5; break;
case '4': val = 4; break;
case '3': val = 3; break;
case '2': val = 2; break;
case '1': val = 1; break;
case '0': val = 0; break;
default: return -EINVAL;
}
if (even) {
cur = val << 4;
} else {
cur += val;
str.push_back(cur);
cur = 0;
}
even = !even;
}
return even ? OK : -EINVAL;
}
static const char* kLookup = "0123456789abcdef";
status_t StrToHex(const std::string& str, std::string& hex) {
hex.clear();
for (size_t i = 0; i < str.size(); i++) {
hex.push_back(kLookup[(str[i] & 0xF0) >> 4]);
hex.push_back(kLookup[str[i] & 0x0F]);
}
return OK;
}
status_t StrToHex(const KeyBuffer& str, KeyBuffer& hex) {
hex.clear();
for (size_t i = 0; i < str.size(); i++) {
hex.push_back(kLookup[(str.data()[i] & 0xF0) >> 4]);
hex.push_back(kLookup[str.data()[i] & 0x0F]);
}
return OK;
}
status_t NormalizeHex(const std::string& in, std::string& out) {
std::string tmp;
if (HexToStr(in, tmp)) {
return -EINVAL;
}
return StrToHex(tmp, out);
}
uint64_t GetFreeBytes(const std::string& path) {
struct statvfs sb;
if (statvfs(path.c_str(), &sb) == 0) {
return (uint64_t) sb.f_bavail * sb.f_frsize;
} else {
return -1;
}
}
// TODO: borrowed from frameworks/native/libs/diskusage/ which should
// eventually be migrated into system/
static int64_t stat_size(struct stat *s) {
int64_t blksize = s->st_blksize;
// count actual blocks used instead of nominal file size
int64_t size = s->st_blocks * 512;
if (blksize) {
/* round up to filesystem block size */
size = (size + blksize - 1) & (~(blksize - 1));
}
return size;
}
// TODO: borrowed from frameworks/native/libs/diskusage/ which should
// eventually be migrated into system/
int64_t calculate_dir_size(int dfd) {
int64_t size = 0;
struct stat s;
DIR *d;
struct dirent *de;
d = fdopendir(dfd);
if (d == NULL) {
close(dfd);
return 0;
}
while ((de = readdir(d))) {
const char *name = de->d_name;
if (fstatat(dfd, name, &s, AT_SYMLINK_NOFOLLOW) == 0) {
size += stat_size(&s);
}
if (de->d_type == DT_DIR) {
int subfd;
/* always skip "." and ".." */
if (name[0] == '.') {
if (name[1] == 0)
continue;
if ((name[1] == '.') && (name[2] == 0))
continue;
}
subfd = openat(dfd, name, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
if (subfd >= 0) {
size += calculate_dir_size(subfd);
}
}
}
closedir(d);
return size;
}
uint64_t GetTreeBytes(const std::string& path) {
int dirfd = open(path.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
if (dirfd < 0) {
PLOG(WARNING) << "Failed to open " << path;
return -1;
} else {
uint64_t res = calculate_dir_size(dirfd);
close(dirfd);
return res;
}
}
bool IsFilesystemSupported(const std::string& fsType) {
std::string supported;
if (!ReadFileToString(kProcFilesystems, &supported)) {
PLOG(ERROR) << "Failed to read supported filesystems";
return false;
}
return supported.find(fsType + "\n") != std::string::npos;
}
status_t WipeBlockDevice(const std::string& path) {
status_t res = -1;
const char* c_path = path.c_str();
unsigned long nr_sec = 0;
unsigned long long range[2];
int fd = TEMP_FAILURE_RETRY(open(c_path, O_RDWR | O_CLOEXEC));
if (fd == -1) {
PLOG(ERROR) << "Failed to open " << path;
goto done;
}
if ((ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) {
PLOG(ERROR) << "Failed to determine size of " << path;
goto done;
}
range[0] = 0;
range[1] = (unsigned long long) nr_sec * 512;
LOG(INFO) << "About to discard " << range[1] << " on " << path;
if (ioctl(fd, BLKDISCARD, &range) == 0) {
LOG(INFO) << "Discard success on " << path;
res = 0;
} else {
PLOG(ERROR) << "Discard failure on " << path;
}
done:
close(fd);
return res;
}
static bool isValidFilename(const std::string& name) {
if (name.empty() || (name == ".") || (name == "..")
|| (name.find('/') != std::string::npos)) {
return false;
} else {
return true;
}
}
std::string BuildKeyPath(const std::string& partGuid) {
return StringPrintf("%s/expand_%s.key", kKeyPath, partGuid.c_str());
}
std::string BuildDataSystemLegacyPath(userid_t userId) {
return StringPrintf("%s/system/users/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataSystemCePath(userid_t userId) {
return StringPrintf("%s/system_ce/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataSystemDePath(userid_t userId) {
return StringPrintf("%s/system_de/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataMiscLegacyPath(userid_t userId) {
return StringPrintf("%s/misc/user/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataMiscCePath(userid_t userId) {
return StringPrintf("%s/misc_ce/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataMiscDePath(userid_t userId) {
return StringPrintf("%s/misc_de/%u", BuildDataPath("").c_str(), userId);
}
// Keep in sync with installd (frameworks/native/cmds/installd/utils.h)
std::string BuildDataProfilesDePath(userid_t userId) {
return StringPrintf("%s/misc/profiles/cur/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataVendorCePath(userid_t userId) {
return StringPrintf("%s/vendor_ce/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataVendorDePath(userid_t userId) {
return StringPrintf("%s/vendor_de/%u", BuildDataPath("").c_str(), userId);
}
std::string BuildDataPath(const std::string& volumeUuid) {
// TODO: unify with installd path generation logic
if (volumeUuid.empty()) {
return "/data";
} else {
CHECK(isValidFilename(volumeUuid));
return StringPrintf("/mnt/expand/%s", volumeUuid.c_str());
}
}
std::string BuildDataMediaCePath(const std::string& volumeUuid, userid_t userId) {
// TODO: unify with installd path generation logic
std::string data(BuildDataPath(volumeUuid));
return StringPrintf("%s/media/%u", data.c_str(), userId);
}
std::string BuildDataUserCePath(const std::string& volumeUuid, userid_t userId) {
// TODO: unify with installd path generation logic
std::string data(BuildDataPath(volumeUuid));
if (volumeUuid.empty() && userId == 0) {
std::string legacy = StringPrintf("%s/data", data.c_str());
struct stat sb;
if (lstat(legacy.c_str(), &sb) == 0 && S_ISDIR(sb.st_mode)) {
/* /data/data is dir, return /data/data for legacy system */
return legacy;
}
}
return StringPrintf("%s/user/%u", data.c_str(), userId);
}
std::string BuildDataUserDePath(const std::string& volumeUuid, userid_t userId) {
// TODO: unify with installd path generation logic
std::string data(BuildDataPath(volumeUuid));
return StringPrintf("%s/user_de/%u", data.c_str(), userId);
}
dev_t GetDevice(const std::string& path) {
struct stat sb;
if (stat(path.c_str(), &sb)) {
PLOG(WARNING) << "Failed to stat " << path;
return 0;
} else {
return sb.st_dev;
}
}
status_t RestoreconRecursive(const std::string& path) {
LOG(VERBOSE) << "Starting restorecon of " << path;
static constexpr const char* kRestoreconString = "selinux.restorecon_recursive";
android::base::SetProperty(kRestoreconString, "");
android::base::SetProperty(kRestoreconString, path);
android::base::WaitForProperty(kRestoreconString, path);
LOG(VERBOSE) << "Finished restorecon of " << path;
return OK;
}
bool Readlinkat(int dirfd, const std::string& path, std::string* result) {
// Shamelessly borrowed from android::base::Readlink()
result->clear();
// Most Linux file systems (ext2 and ext4, say) limit symbolic links to
// 4095 bytes. Since we'll copy out into the string anyway, it doesn't
// waste memory to just start there. We add 1 so that we can recognize
// whether it actually fit (rather than being truncated to 4095).
std::vector<char> buf(4095 + 1);
while (true) {
ssize_t size = readlinkat(dirfd, path.c_str(), &buf[0], buf.size());
// Unrecoverable error?
if (size == -1)
return false;
// It fit! (If size == buf.size(), it may have been truncated.)
if (static_cast<size_t>(size) < buf.size()) {
result->assign(&buf[0], size);
return true;
}
// Double our buffer and try again.
buf.resize(buf.size() * 2);
}
}
bool IsRunningInEmulator() {
return android::base::GetBoolProperty("ro.kernel.qemu", false);
}
} // namespace vold
} // namespace android