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/*
* Copyright (C) 2016 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 LOG_TAG "dumpstate"
#include "DumpstateInternal.h"
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <sys/capability.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <cstdint>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <cutils/log.h>
#include <private/android_filesystem_config.h>
uint64_t Nanotime() {
timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return static_cast<uint64_t>(ts.tv_sec * NANOS_PER_SEC + ts.tv_nsec);
}
// Switches to non-root user and group.
bool DropRootUser() {
if (getgid() == AID_SHELL && getuid() == AID_SHELL) {
MYLOGD("drop_root_user(): already running as Shell\n");
return true;
}
/* ensure we will keep capabilities when we drop root */
if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
MYLOGE("prctl(PR_SET_KEEPCAPS) failed: %s\n", strerror(errno));
return false;
}
gid_t groups[] = {AID_LOG, AID_SDCARD_R, AID_SDCARD_RW, AID_MOUNT,
AID_INET, AID_NET_BW_STATS, AID_READPROC, AID_BLUETOOTH};
if (setgroups(sizeof(groups) / sizeof(groups[0]), groups) != 0) {
MYLOGE("Unable to setgroups, aborting: %s\n", strerror(errno));
return false;
}
if (setgid(AID_SHELL) != 0) {
MYLOGE("Unable to setgid, aborting: %s\n", strerror(errno));
return false;
}
if (setuid(AID_SHELL) != 0) {
MYLOGE("Unable to setuid, aborting: %s\n", strerror(errno));
return false;
}
struct __user_cap_header_struct capheader;
struct __user_cap_data_struct capdata[2];
memset(&capheader, 0, sizeof(capheader));
memset(&capdata, 0, sizeof(capdata));
capheader.version = _LINUX_CAPABILITY_VERSION_3;
capheader.pid = 0;
capdata[CAP_TO_INDEX(CAP_SYSLOG)].permitted = CAP_TO_MASK(CAP_SYSLOG);
capdata[CAP_TO_INDEX(CAP_SYSLOG)].effective = CAP_TO_MASK(CAP_SYSLOG);
capdata[0].inheritable = 0;
capdata[1].inheritable = 0;
if (capset(&capheader, &capdata[0]) < 0) {
MYLOGE("capset failed: %s\n", strerror(errno));
return false;
}
return true;
}
int DumpFileFromFdToFd(const std::string& title, const std::string& path_string, int fd, int out_fd,
bool dry_run) {
const char* path = path_string.c_str();
if (!title.empty()) {
dprintf(out_fd, "------ %s (%s", title.c_str(), path);
struct stat st;
// Only show the modification time of non-device files.
size_t path_len = strlen(path);
if ((path_len < 6 || memcmp(path, "/proc/", 6)) &&
(path_len < 5 || memcmp(path, "/sys/", 5)) &&
(path_len < 3 || memcmp(path, "/d/", 3)) && !fstat(fd, &st)) {
char stamp[80];
time_t mtime = st.st_mtime;
strftime(stamp, sizeof(stamp), "%Y-%m-%d %H:%M:%S", localtime(&mtime));
dprintf(out_fd, ": %s", stamp);
}
dprintf(out_fd, ") ------\n");
fsync(out_fd);
}
if (dry_run) {
if (out_fd != STDOUT_FILENO) {
// There is no title, but we should still print a dry-run message
dprintf(out_fd, "%s: skipped on dry run\n", path);
} else if (!title.empty()) {
dprintf(out_fd, "\t(skipped on dry run)\n");
}
fsync(out_fd);
return 0;
}
bool newline = false;
fd_set read_set;
timeval tm;
while (true) {
FD_ZERO(&read_set);
FD_SET(fd, &read_set);
/* Timeout if no data is read for 30 seconds. */
tm.tv_sec = 30;
tm.tv_usec = 0;
uint64_t elapsed = Nanotime();
int ret = TEMP_FAILURE_RETRY(select(fd + 1, &read_set, nullptr, nullptr, &tm));
if (ret == -1) {
dprintf(out_fd, "*** %s: select failed: %s\n", path, strerror(errno));
newline = true;
break;
} else if (ret == 0) {
elapsed = Nanotime() - elapsed;
dprintf(out_fd, "*** %s: Timed out after %.3fs\n", path, (float)elapsed / NANOS_PER_SEC);
newline = true;
break;
} else {
char buffer[65536];
ssize_t bytes_read = TEMP_FAILURE_RETRY(read(fd, buffer, sizeof(buffer)));
if (bytes_read > 0) {
android::base::WriteFully(out_fd, buffer, bytes_read);
newline = (buffer[bytes_read - 1] == '\n');
} else {
if (bytes_read == -1) {
dprintf(out_fd, "*** %s: Failed to read from fd: %s", path, strerror(errno));
newline = true;
}
break;
}
}
}
close(fd);
if (!newline) dprintf(out_fd, "\n");
if (!title.empty()) dprintf(out_fd, "\n");
return 0;
}
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