blob: 1937c2817e65e1e2afc4670f489525286aac1803 [file] [log] [blame]
/*
* 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 "sehandle.h"
#include "Utils.h"
#include "Process.h"
#include <base/logging.h>
#include <base/stringprintf.h>
#include <cutils/fs.h>
#include <private/android_filesystem_config.h>
#include <logwrap/logwrap.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/wait.h>
#ifndef UMOUNT_NOFOLLOW
#define UMOUNT_NOFOLLOW 0x00000008 /* Don't follow symlink on umount */
#endif
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;
static const char* kBlkidPath = "/system/bin/blkid";
status_t CreateDeviceNode(const std::string& path, dev_t dev) {
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) {
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;
}
PLOG(WARNING) << "Failed to unmount " << path;
sleep(5);
Process::killProcessesWithOpenFiles(cpath, SIGTERM);
if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
return OK;
}
PLOG(WARNING) << "Failed to unmount " << path;
sleep(5);
Process::killProcessesWithOpenFiles(cpath, SIGKILL);
if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
return OK;
}
PLOG(ERROR) << "Failed to unmount " << path;
return -errno;
}
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;
}
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::string cmd(StringPrintf("%s -c /dev/null %s", kBlkidPath, path.c_str()));
if (setexeccon(untrusted ? sBlkidUntrustedContext : sBlkidContext)) {
LOG(ERROR) << "Failed to setexeccon()";
return -EPERM;
}
FILE* fp = popen(cmd.c_str(), "r");
if (setexeccon(NULL)) {
abort();
}
if (!fp) {
PLOG(ERROR) << "Failed to run " << cmd;
return -errno;
}
status_t res = OK;
char line[1024];
char value[128];
if (fgets(line, sizeof(line), fp) != nullptr) {
LOG(DEBUG) << "blkid identified " << path << " as " << line;
// Extract values from blkid output, if defined
char* start = strstr(line, "TYPE=");
if (start != nullptr && sscanf(start + 5, "\"%127[^\"]\"", value) == 1) {
fsType = value;
}
start = strstr(line, "UUID=");
if (start != nullptr && sscanf(start + 5, "\"%127[^\"]\"", value) == 1) {
fsUuid = value;
}
start = strstr(line, "LABEL=");
if (start != nullptr && sscanf(start + 6, "\"%127[^\"]\"", value) == 1) {
fsLabel = value;
}
} else {
LOG(WARNING) << "blkid failed to identify " << path;
res = -ENODATA;
}
pclose(fp);
return res;
}
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, int* status,
bool ignore_int_quit, bool logwrap) {
int argc = args.size();
char** argv = (char**) calloc(argc, sizeof(char*));
for (int i = 0; i < argc; i++) {
argv[i] = (char*) args[i].c_str();
if (i == 0) {
LOG(VERBOSE) << args[i];
} else {
LOG(VERBOSE) << " " << args[i];
}
}
int res = android_fork_execvp(argc, argv, status, ignore_int_quit, logwrap);
free(argv);
return res;
}
status_t ReadRandomBytes(size_t bytes, std::string& out) {
out.clear();
int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
if (fd == -1) {
return -errno;
}
char buf[BUFSIZ];
size_t n;
while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], std::min(sizeof(buf), bytes)))) > 0) {
out.append(buf, n);
bytes -= n;
}
TEMP_FAILURE_RETRY(close(fd));
if (bytes == 0) {
return OK;
} else {
return -EIO;
}
}
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] >> 4]);
hex.push_back(kLookup[str[i] & 0x0F]);
}
return OK;
}
} // namespace vold
} // namespace android