268 lines
8.1 KiB
C++
268 lines
8.1 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define TRACE_TAG ADB
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#include "sysdeps.h"
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <getopt.h>
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#include <sys/prctl.h>
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#include "base/logging.h"
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#include "base/stringprintf.h"
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#include "cutils/properties.h"
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#include "private/android_filesystem_config.h"
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#include "selinux/selinux.h"
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#include "adb.h"
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#include "adb_auth.h"
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#include "adb_listeners.h"
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#include "transport.h"
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static const char* root_seclabel = nullptr;
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static void drop_capabilities_bounding_set_if_needed() {
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#ifdef ALLOW_ADBD_ROOT
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char value[PROPERTY_VALUE_MAX];
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property_get("ro.debuggable", value, "");
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if (strcmp(value, "1") == 0) {
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return;
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}
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#endif
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for (int i = 0; prctl(PR_CAPBSET_READ, i, 0, 0, 0) >= 0; i++) {
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if (i == CAP_SETUID || i == CAP_SETGID) {
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// CAP_SETUID CAP_SETGID needed by /system/bin/run-as
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continue;
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}
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int err = prctl(PR_CAPBSET_DROP, i, 0, 0, 0);
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// Some kernels don't have file capabilities compiled in, and
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// prctl(PR_CAPBSET_DROP) returns EINVAL. Don't automatically
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// die when we see such misconfigured kernels.
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if ((err < 0) && (errno != EINVAL)) {
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PLOG(FATAL) << "Could not drop capabilities";
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}
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}
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}
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static bool should_drop_privileges() {
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#if defined(ALLOW_ADBD_ROOT)
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char value[PROPERTY_VALUE_MAX];
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// The properties that affect `adb root` and `adb unroot` are ro.secure and
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// ro.debuggable. In this context the names don't make the expected behavior
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// particularly obvious.
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//
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// ro.debuggable:
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// Allowed to become root, but not necessarily the default. Set to 1 on
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// eng and userdebug builds.
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//
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// ro.secure:
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// Drop privileges by default. Set to 1 on userdebug and user builds.
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property_get("ro.secure", value, "1");
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bool ro_secure = (strcmp(value, "1") == 0);
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property_get("ro.debuggable", value, "");
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bool ro_debuggable = (strcmp(value, "1") == 0);
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// Drop privileges if ro.secure is set...
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bool drop = ro_secure;
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property_get("service.adb.root", value, "");
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bool adb_root = (strcmp(value, "1") == 0);
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bool adb_unroot = (strcmp(value, "0") == 0);
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// ...except "adb root" lets you keep privileges in a debuggable build.
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if (ro_debuggable && adb_root) {
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drop = false;
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}
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// ...and "adb unroot" lets you explicitly drop privileges.
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if (adb_unroot) {
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drop = true;
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}
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return drop;
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#else
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return true; // "adb root" not allowed, always drop privileges.
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#endif // ALLOW_ADBD_ROOT
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}
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int adbd_main(int server_port) {
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umask(0);
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signal(SIGPIPE, SIG_IGN);
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init_transport_registration();
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// We need to call this even if auth isn't enabled because the file
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// descriptor will always be open.
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adbd_cloexec_auth_socket();
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if (ALLOW_ADBD_NO_AUTH && property_get_bool("ro.adb.secure", 0) == 0) {
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auth_required = false;
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}
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adbd_auth_init();
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// Our external storage path may be different than apps, since
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// we aren't able to bind mount after dropping root.
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const char* adb_external_storage = getenv("ADB_EXTERNAL_STORAGE");
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if (adb_external_storage != nullptr) {
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setenv("EXTERNAL_STORAGE", adb_external_storage, 1);
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} else {
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D("Warning: ADB_EXTERNAL_STORAGE is not set. Leaving EXTERNAL_STORAGE"
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" unchanged.\n");
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}
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// Add extra groups:
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// AID_ADB to access the USB driver
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// AID_LOG to read system logs (adb logcat)
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// AID_INPUT to diagnose input issues (getevent)
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// AID_INET to diagnose network issues (ping)
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// AID_NET_BT and AID_NET_BT_ADMIN to diagnose bluetooth (hcidump)
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// AID_SDCARD_R to allow reading from the SD card
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// AID_SDCARD_RW to allow writing to the SD card
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// AID_NET_BW_STATS to read out qtaguid statistics
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// AID_READPROC for reading /proc entries across UID boundaries
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gid_t groups[] = {AID_ADB, AID_LOG, AID_INPUT,
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AID_INET, AID_NET_BT, AID_NET_BT_ADMIN,
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AID_SDCARD_R, AID_SDCARD_RW, AID_NET_BW_STATS,
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AID_READPROC };
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if (setgroups(sizeof(groups) / sizeof(groups[0]), groups) != 0) {
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PLOG(FATAL) << "Could not set supplemental groups";
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}
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/* don't listen on a port (default 5037) if running in secure mode */
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/* don't run as root if we are running in secure mode */
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if (should_drop_privileges()) {
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drop_capabilities_bounding_set_if_needed();
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/* then switch user and group to "shell" */
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if (setgid(AID_SHELL) != 0) {
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PLOG(FATAL) << "Could not setgid";
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}
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if (setuid(AID_SHELL) != 0) {
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PLOG(FATAL) << "Could not setuid";
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}
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D("Local port disabled");
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} else {
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if (root_seclabel != nullptr) {
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if (setcon(root_seclabel) < 0) {
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LOG(FATAL) << "Could not set SELinux context";
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}
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}
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std::string error;
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std::string local_name =
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android::base::StringPrintf("tcp:%d", server_port);
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if (install_listener(local_name, "*smartsocket*", nullptr, 0,
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&error)) {
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LOG(FATAL) << "Could not install *smartsocket* listener: "
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<< error;
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}
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}
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bool is_usb = false;
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if (access(USB_ADB_PATH, F_OK) == 0 || access(USB_FFS_ADB_EP0, F_OK) == 0) {
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// Listen on USB.
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usb_init();
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is_usb = true;
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}
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// If one of these properties is set, also listen on that port.
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// If one of the properties isn't set and we couldn't listen on usb, listen
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// on the default port.
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char prop_port[PROPERTY_VALUE_MAX];
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property_get("service.adb.tcp.port", prop_port, "");
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if (prop_port[0] == '\0') {
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property_get("persist.adb.tcp.port", prop_port, "");
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}
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int port;
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if (sscanf(prop_port, "%d", &port) == 1 && port > 0) {
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D("using port=%d", port);
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// Listen on TCP port specified by service.adb.tcp.port property.
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local_init(port);
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} else if (!is_usb) {
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// Listen on default port.
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local_init(DEFAULT_ADB_LOCAL_TRANSPORT_PORT);
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}
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D("adbd_main(): pre init_jdwp()");
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init_jdwp();
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D("adbd_main(): post init_jdwp()");
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D("Event loop starting");
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fdevent_loop();
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return 0;
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}
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static void close_stdin() {
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int fd = unix_open("/dev/null", O_RDONLY);
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if (fd == -1) {
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perror("failed to open /dev/null, stdin will remain open");
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return;
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}
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dup2(fd, STDIN_FILENO);
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unix_close(fd);
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}
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int main(int argc, char** argv) {
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while (true) {
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static struct option opts[] = {
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{"root_seclabel", required_argument, nullptr, 's'},
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{"device_banner", required_argument, nullptr, 'b'},
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{"version", no_argument, nullptr, 'v'},
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};
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int option_index = 0;
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int c = getopt_long(argc, argv, "", opts, &option_index);
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if (c == -1) {
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break;
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}
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switch (c) {
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case 's':
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root_seclabel = optarg;
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break;
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case 'b':
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adb_device_banner = optarg;
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break;
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case 'v':
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printf("Android Debug Bridge Daemon version %d.%d.%d %s\n",
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ADB_VERSION_MAJOR, ADB_VERSION_MINOR, ADB_SERVER_VERSION,
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ADB_REVISION);
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return 0;
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default:
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// getopt already prints "adbd: invalid option -- %c" for us.
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return 1;
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}
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}
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close_stdin();
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adb_trace_init(argv);
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D("Handling main()");
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return adbd_main(DEFAULT_ADB_PORT);
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}
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