/*
* Copyright (C) 2007 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.
*/
#define TRACE_TAG SYNC
#include "sysdeps.h"
#include "file_sync_service.h"
#include <dirent.h>
#include <errno.h>
#include <log/log.h>
#include <selinux/android.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <utime.h>
#include "adb.h"
#include "adb_io.h"
#include "adb_utils.h"
#include "private/android_filesystem_config.h"
#include "security_log_tags.h"
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
static bool should_use_fs_config(const std::string& path) {
// TODO: use fs_config to configure permissions on /data.
return android::base::StartsWith(path, "/system/") ||
android::base::StartsWith(path, "/vendor/") ||
android::base::StartsWith(path, "/oem/");
}
static bool secure_mkdirs(const std::string& path) {
uid_t uid = -1;
gid_t gid = -1;
unsigned int mode = 0775;
uint64_t cap = 0;
if (path[0] != '/') return false;
std::vector<std::string> path_components = android::base::Split(path, "/");
std::string partial_path;
for (const auto& path_component : path_components) {
if (partial_path.back() != OS_PATH_SEPARATOR) partial_path += OS_PATH_SEPARATOR;
partial_path += path_component;
if (should_use_fs_config(partial_path)) {
fs_config(partial_path.c_str(), 1, nullptr, &uid, &gid, &mode, &cap);
}
if (adb_mkdir(partial_path.c_str(), mode) == -1) {
if (errno != EEXIST) {
return false;
}
} else {
if (chown(partial_path.c_str(), uid, gid) == -1) {
return false;
}
// Not all filesystems support setting SELinux labels. http://b/23530370.
selinux_android_restorecon(partial_path.c_str(), 0);
}
}
return true;
}
static bool do_stat(int s, const char* path) {
syncmsg msg;
msg.stat.id = ID_STAT;
struct stat st;
memset(&st, 0, sizeof(st));
// TODO: add a way to report that the stat failed!
lstat(path, &st);
msg.stat.mode = st.st_mode;
msg.stat.size = st.st_size;
msg.stat.time = st.st_mtime;
return WriteFdExactly(s, &msg.stat, sizeof(msg.stat));
}
static bool do_list(int s, const char* path) {
dirent* de;
syncmsg msg;
msg.dent.id = ID_DENT;
std::unique_ptr<DIR, int(*)(DIR*)> d(opendir(path), closedir);
if (!d) goto done;
while ((de = readdir(d.get()))) {
std::string filename(android::base::StringPrintf("%s/%s", path, de->d_name));
struct stat st;
if (lstat(filename.c_str(), &st) == 0) {
size_t d_name_length = strlen(de->d_name);
msg.dent.mode = st.st_mode;
msg.dent.size = st.st_size;
msg.dent.time = st.st_mtime;
msg.dent.namelen = d_name_length;
if (!WriteFdExactly(s, &msg.dent, sizeof(msg.dent)) ||
!WriteFdExactly(s, de->d_name, d_name_length)) {
return false;
}
}
}
done:
msg.dent.id = ID_DONE;
msg.dent.mode = 0;
msg.dent.size = 0;
msg.dent.time = 0;
msg.dent.namelen = 0;
return WriteFdExactly(s, &msg.dent, sizeof(msg.dent));
}
// Make sure that SendFail from adb_io.cpp isn't accidentally used in this file.
#pragma GCC poison SendFail
static bool SendSyncFail(int fd, const std::string& reason) {
D("sync: failure: %s", reason.c_str());
syncmsg msg;
msg.data.id = ID_FAIL;
msg.data.size = reason.size();
return WriteFdExactly(fd, &msg.data, sizeof(msg.data)) && WriteFdExactly(fd, reason);
}
static bool SendSyncFailErrno(int fd, const std::string& reason) {
return SendSyncFail(fd, android::base::StringPrintf("%s: %s", reason.c_str(), strerror(errno)));
}
static bool handle_send_file(int s, const char* path, uid_t uid,
gid_t gid, mode_t mode, std::vector<char>& buffer, bool do_unlink) {
syncmsg msg;
unsigned int timestamp = 0;
__android_log_security_bswrite(SEC_TAG_ADB_SEND_FILE, path);
int fd = adb_open_mode(path, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, mode);
if (fd < 0 && errno == ENOENT) {
if (!secure_mkdirs(adb_dirname(path))) {
SendSyncFailErrno(s, "secure_mkdirs failed");
goto fail;
}
fd = adb_open_mode(path, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, mode);
}
if (fd < 0 && errno == EEXIST) {
fd = adb_open_mode(path, O_WRONLY | O_CLOEXEC, mode);
}
if (fd < 0) {
SendSyncFailErrno(s, "couldn't create file");
goto fail;
} else {
if (fchown(fd, uid, gid) == -1) {
SendSyncFailErrno(s, "fchown failed");
goto fail;
}
// Not all filesystems support setting SELinux labels. http://b/23530370.
selinux_android_restorecon(path, 0);
// fchown clears the setuid bit - restore it if present.
// Ignore the result of calling fchmod. It's not supported
// by all filesystems. b/12441485
fchmod(fd, mode);
}
while (true) {
if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) goto fail;
if (msg.data.id != ID_DATA) {
if (msg.data.id == ID_DONE) {
timestamp = msg.data.size;
break;
}
SendSyncFail(s, "invalid data message");
goto abort;
}
if (msg.data.size > buffer.size()) { // TODO: resize buffer?
SendSyncFail(s, "oversize data message");
goto abort;
}
if (!ReadFdExactly(s, &buffer[0], msg.data.size)) goto abort;
if (!WriteFdExactly(fd, &buffer[0], msg.data.size)) {
SendSyncFailErrno(s, "write failed");
goto fail;
}
}
adb_close(fd);
utimbuf u;
u.actime = timestamp;
u.modtime = timestamp;
utime(path, &u);
msg.status.id = ID_OKAY;
msg.status.msglen = 0;
return WriteFdExactly(s, &msg.status, sizeof(msg.status));
fail:
// If there's a problem on the device, we'll send an ID_FAIL message and
// close the socket. Unfortunately the kernel will sometimes throw that
// data away if the other end keeps writing without reading (which is
// the case with old versions of adb). To maintain compatibility, keep
// reading and throwing away ID_DATA packets until the other side notices
// that we've reported an error.
while (true) {
if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) goto fail;
if (msg.data.id == ID_DONE) {
goto abort;
} else if (msg.data.id != ID_DATA) {
char id[5];
memcpy(id, &msg.data.id, sizeof(msg.data.id));
id[4] = '\0';
D("handle_send_fail received unexpected id '%s' during failure", id);
goto abort;
}
if (msg.data.size > buffer.size()) {
D("handle_send_fail received oversized packet of length '%u' during failure",
msg.data.size);
goto abort;
}
if (!ReadFdExactly(s, &buffer[0], msg.data.size)) goto abort;
}
abort:
if (fd >= 0) adb_close(fd);
if (do_unlink) adb_unlink(path);
return false;
}
#if defined(_WIN32)
extern bool handle_send_link(int s, const std::string& path, std::vector<char>& buffer) __attribute__((error("no symlinks on Windows")));
#else
static bool handle_send_link(int s, const std::string& path, std::vector<char>& buffer) {
syncmsg msg;
unsigned int len;
int ret;
if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) return false;
if (msg.data.id != ID_DATA) {
SendSyncFail(s, "invalid data message: expected ID_DATA");
return false;
}
len = msg.data.size;
if (len > buffer.size()) { // TODO: resize buffer?
SendSyncFail(s, "oversize data message");
return false;
}
if (!ReadFdExactly(s, &buffer[0], len)) return false;
ret = symlink(&buffer[0], path.c_str());
if (ret && errno == ENOENT) {
if (!secure_mkdirs(adb_dirname(path))) {
SendSyncFailErrno(s, "secure_mkdirs failed");
return false;
}
ret = symlink(&buffer[0], path.c_str());
}
if (ret) {
SendSyncFailErrno(s, "symlink failed");
return false;
}
if (!ReadFdExactly(s, &msg.data, sizeof(msg.data))) return false;
if (msg.data.id == ID_DONE) {
msg.status.id = ID_OKAY;
msg.status.msglen = 0;
if (!WriteFdExactly(s, &msg.status, sizeof(msg.status))) return false;
} else {
SendSyncFail(s, "invalid data message: expected ID_DONE");
return false;
}
return true;
}
#endif
static bool do_send(int s, const std::string& spec, std::vector<char>& buffer) {
// 'spec' is of the form "/some/path,0755". Break it up.
size_t comma = spec.find_last_of(',');
if (comma == std::string::npos) {
SendSyncFail(s, "missing , in ID_SEND");
return false;
}
std::string path = spec.substr(0, comma);
errno = 0;
mode_t mode = strtoul(spec.substr(comma + 1).c_str(), nullptr, 0);
if (errno != 0) {
SendSyncFail(s, "bad mode");
return false;
}
// Don't delete files before copying if they are not "regular" or symlinks.
struct stat st;
bool do_unlink = (lstat(path.c_str(), &st) == -1) || S_ISREG(st.st_mode) || S_ISLNK(st.st_mode);
if (do_unlink) {
adb_unlink(path.c_str());
}
if (S_ISLNK(mode)) {
return handle_send_link(s, path.c_str(), buffer);
}
// Copy user permission bits to "group" and "other" permissions.
mode &= 0777;
mode |= ((mode >> 3) & 0070);
mode |= ((mode >> 3) & 0007);
uid_t uid = -1;
gid_t gid = -1;
uint64_t cap = 0;
if (should_use_fs_config(path)) {
unsigned int broken_api_hack = mode;
fs_config(path.c_str(), 0, nullptr, &uid, &gid, &broken_api_hack, &cap);
mode = broken_api_hack;
}
return handle_send_file(s, path.c_str(), uid, gid, mode, buffer, do_unlink);
}
static bool do_recv(int s, const char* path, std::vector<char>& buffer) {
__android_log_security_bswrite(SEC_TAG_ADB_RECV_FILE, path);
int fd = adb_open(path, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
SendSyncFailErrno(s, "open failed");
return false;
}
syncmsg msg;
msg.data.id = ID_DATA;
while (true) {
int r = adb_read(fd, &buffer[0], buffer.size());
if (r <= 0) {
if (r == 0) break;
SendSyncFailErrno(s, "read failed");
adb_close(fd);
return false;
}
msg.data.size = r;
if (!WriteFdExactly(s, &msg.data, sizeof(msg.data)) || !WriteFdExactly(s, &buffer[0], r)) {
adb_close(fd);
return false;
}
}
adb_close(fd);
msg.data.id = ID_DONE;
msg.data.size = 0;
return WriteFdExactly(s, &msg.data, sizeof(msg.data));
}
static bool handle_sync_command(int fd, std::vector<char>& buffer) {
D("sync: waiting for request");
SyncRequest request;
if (!ReadFdExactly(fd, &request, sizeof(request))) {
SendSyncFail(fd, "command read failure");
return false;
}
size_t path_length = request.path_length;
if (path_length > 1024) {
SendSyncFail(fd, "path too long");
return false;
}
char name[1025];
if (!ReadFdExactly(fd, name, path_length)) {
SendSyncFail(fd, "filename read failure");
return false;
}
name[path_length] = 0;
const char* id = reinterpret_cast<const char*>(&request.id);
D("sync: '%.4s' '%s'", id, name);
switch (request.id) {
case ID_STAT:
if (!do_stat(fd, name)) return false;
break;
case ID_LIST:
if (!do_list(fd, name)) return false;
break;
case ID_SEND:
if (!do_send(fd, name, buffer)) return false;
break;
case ID_RECV:
if (!do_recv(fd, name, buffer)) return false;
break;
case ID_QUIT:
return false;
default:
SendSyncFail(fd, android::base::StringPrintf("unknown command '%.4s' (%08x)",
id, request.id));
return false;
}
return true;
}
void file_sync_service(int fd, void* cookie) {
std::vector<char> buffer(SYNC_DATA_MAX);
while (handle_sync_command(fd, buffer)) {
}
D("sync: done");
adb_close(fd);
}