blob: a6e8998d3a5e1b856d325d513906e334618f3a48 [file] [log] [blame]
/*
* Copyright (C) 2018 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 "adb_install.h"
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include "adb.h"
#include "adb_client.h"
#include "adb_unique_fd.h"
#include "adb_utils.h"
#include "client/file_sync_client.h"
#include "commandline.h"
#include "fastdeploy.h"
#if defined(ENABLE_FASTDEPLOY)
static constexpr int kFastDeployMinApi = 24;
#endif
namespace {
enum InstallMode {
INSTALL_DEFAULT,
INSTALL_PUSH,
INSTALL_STREAM,
};
}
static bool can_use_feature(const char* feature) {
FeatureSet features;
std::string error;
if (!adb_get_feature_set(&features, &error)) {
fprintf(stderr, "error: %s\n", error.c_str());
return false;
}
return CanUseFeature(features, feature);
}
static InstallMode best_install_mode() {
if (can_use_feature(kFeatureCmd)) {
return INSTALL_STREAM;
}
return INSTALL_PUSH;
}
static bool is_apex_supported() {
return can_use_feature(kFeatureApex);
}
static int pm_command(int argc, const char** argv) {
std::string cmd = "pm";
while (argc-- > 0) {
cmd += " " + escape_arg(*argv++);
}
return send_shell_command(cmd);
}
static int uninstall_app_streamed(int argc, const char** argv) {
// 'adb uninstall' takes the same arguments as 'cmd package uninstall' on device
std::string cmd = "cmd package";
while (argc-- > 0) {
// deny the '-k' option until the remaining data/cache can be removed with adb/UI
if (strcmp(*argv, "-k") == 0) {
printf("The -k option uninstalls the application while retaining the "
"data/cache.\n"
"At the moment, there is no way to remove the remaining data.\n"
"You will have to reinstall the application with the same "
"signature, and fully "
"uninstall it.\n"
"If you truly wish to continue, execute 'adb shell cmd package "
"uninstall -k'.\n");
return EXIT_FAILURE;
}
cmd += " " + escape_arg(*argv++);
}
return send_shell_command(cmd);
}
static int uninstall_app_legacy(int argc, const char** argv) {
/* if the user choose the -k option, we refuse to do it until devices are
out with the option to uninstall the remaining data somehow (adb/ui) */
for (int i = 1; i < argc; i++) {
if (!strcmp(argv[i], "-k")) {
printf("The -k option uninstalls the application while retaining the "
"data/cache.\n"
"At the moment, there is no way to remove the remaining data.\n"
"You will have to reinstall the application with the same "
"signature, and fully "
"uninstall it.\n"
"If you truly wish to continue, execute 'adb shell pm uninstall "
"-k'\n.");
return EXIT_FAILURE;
}
}
/* 'adb uninstall' takes the same arguments as 'pm uninstall' on device */
return pm_command(argc, argv);
}
int uninstall_app(int argc, const char** argv) {
if (best_install_mode() == INSTALL_PUSH) {
return uninstall_app_legacy(argc, argv);
}
return uninstall_app_streamed(argc, argv);
}
static void read_status_line(int fd, char* buf, size_t count) {
count--;
while (count > 0) {
int len = adb_read(fd, buf, count);
if (len <= 0) {
break;
}
buf += len;
count -= len;
}
*buf = '\0';
}
#if defined(ENABLE_FASTDEPLOY)
static int delete_device_patch_file(const char* apkPath) {
std::string patchDevicePath = get_patch_path(apkPath);
return delete_device_file(patchDevicePath);
}
#endif
static int install_app_streamed(int argc, const char** argv, bool use_fastdeploy,
bool use_localagent) {
printf("Performing Streamed Install\n");
// The last argument must be the APK file
const char* file = argv[argc - 1];
if (!android::base::EndsWithIgnoreCase(file, ".apk") &&
!android::base::EndsWithIgnoreCase(file, ".apex")) {
error_exit("filename doesn't end .apk or .apex: %s", file);
}
bool is_apex = false;
if (android::base::EndsWithIgnoreCase(file, ".apex")) {
is_apex = true;
}
if (is_apex && !is_apex_supported()) {
error_exit(".apex is not supported on the target device");
}
if (is_apex && use_fastdeploy) {
error_exit("--fastdeploy doesn't support .apex files");
}
if (use_fastdeploy == true) {
#if defined(ENABLE_FASTDEPLOY)
TemporaryFile metadataTmpFile;
std::string patchTmpFilePath;
{
TemporaryFile patchTmpFile;
patchTmpFile.DoNotRemove();
patchTmpFilePath = patchTmpFile.path;
}
FILE* metadataFile = fopen(metadataTmpFile.path, "wb");
extract_metadata(file, metadataFile);
fclose(metadataFile);
create_patch(file, metadataTmpFile.path, patchTmpFilePath.c_str());
// pass all but 1st (command) and last (apk path) parameters through to pm for
// session creation
std::vector<const char*> pm_args{argv + 1, argv + argc - 1};
install_patch(file, patchTmpFilePath.c_str(), pm_args.size(), pm_args.data());
adb_unlink(patchTmpFilePath.c_str());
delete_device_patch_file(file);
return 0;
#else
error_exit("fastdeploy is disabled");
#endif
} else {
struct stat sb;
if (stat(file, &sb) == -1) {
fprintf(stderr, "adb: failed to stat %s: %s\n", file, strerror(errno));
return 1;
}
unique_fd local_fd(adb_open(file, O_RDONLY | O_CLOEXEC));
if (local_fd < 0) {
fprintf(stderr, "adb: failed to open %s: %s\n", file, strerror(errno));
return 1;
}
#ifdef __linux__
posix_fadvise(local_fd.get(), 0, 0, POSIX_FADV_SEQUENTIAL | POSIX_FADV_NOREUSE);
#endif
const bool use_abb = can_use_feature(kFeatureAbb);
std::string error;
std::vector<std::string> cmd_args = {use_abb ? "package" : "exec:cmd package"};
cmd_args.reserve(argc + 3);
// don't copy the APK name, but, copy the rest of the arguments as-is
while (argc-- > 1) {
if (use_abb) {
cmd_args.push_back(*argv++);
} else {
cmd_args.push_back(escape_arg(*argv++));
}
}
// add size parameter [required for streaming installs]
// do last to override any user specified value
cmd_args.push_back("-S");
cmd_args.push_back(
android::base::StringPrintf("%" PRIu64, static_cast<uint64_t>(sb.st_size)));
if (is_apex) {
cmd_args.push_back("--apex");
}
unique_fd remote_fd;
if (use_abb) {
remote_fd = send_abb_exec_command(cmd_args, &error);
} else {
remote_fd.reset(adb_connect(android::base::Join(cmd_args, " "), &error));
}
if (remote_fd < 0) {
fprintf(stderr, "adb: connect error for write: %s\n", error.c_str());
return 1;
}
copy_to_file(local_fd.get(), remote_fd.get());
char buf[BUFSIZ];
read_status_line(remote_fd.get(), buf, sizeof(buf));
if (!strncmp("Success", buf, 7)) {
fputs(buf, stdout);
return 0;
}
fprintf(stderr, "adb: failed to install %s: %s", file, buf);
return 1;
}
}
static int install_app_legacy(int argc, const char** argv, bool use_fastdeploy,
bool use_localagent) {
printf("Performing Push Install\n");
// Find last APK argument.
// All other arguments passed through verbatim.
int last_apk = -1;
for (int i = argc - 1; i >= 0; i--) {
if (android::base::EndsWithIgnoreCase(argv[i], ".apex")) {
error_exit("APEX packages are only compatible with Streamed Install");
}
if (android::base::EndsWithIgnoreCase(argv[i], ".apk")) {
last_apk = i;
break;
}
}
if (last_apk == -1) error_exit("need APK file on command line");
int result = -1;
std::vector<const char*> apk_file = {argv[last_apk]};
std::string apk_dest = "/data/local/tmp/" + android::base::Basename(argv[last_apk]);
if (use_fastdeploy == true) {
#if defined(ENABLE_FASTDEPLOY)
TemporaryFile metadataTmpFile;
TemporaryFile patchTmpFile;
FILE* metadataFile = fopen(metadataTmpFile.path, "wb");
extract_metadata(apk_file[0], metadataFile);
fclose(metadataFile);
create_patch(apk_file[0], metadataTmpFile.path, patchTmpFile.path);
apply_patch_on_device(apk_file[0], patchTmpFile.path, apk_dest.c_str());
#else
error_exit("fastdeploy is disabled");
#endif
} else {
if (!do_sync_push(apk_file, apk_dest.c_str(), false)) goto cleanup_apk;
}
argv[last_apk] = apk_dest.c_str(); /* destination name, not source location */
result = pm_command(argc, argv);
cleanup_apk:
if (use_fastdeploy == true) {
#if defined(ENABLE_FASTDEPLOY)
delete_device_patch_file(apk_file[0]);
#endif
}
delete_device_file(apk_dest);
return result;
}
int install_app(int argc, const char** argv) {
std::vector<int> processedArgIndicies;
InstallMode installMode = INSTALL_DEFAULT;
bool use_fastdeploy = false;
bool is_reinstall = false;
bool use_localagent = false;
FastDeploy_AgentUpdateStrategy agent_update_strategy = FastDeploy_AgentUpdateDifferentVersion;
for (int i = 1; i < argc; i++) {
if (!strcmp(argv[i], "--streaming")) {
processedArgIndicies.push_back(i);
installMode = INSTALL_STREAM;
} else if (!strcmp(argv[i], "--no-streaming")) {
processedArgIndicies.push_back(i);
installMode = INSTALL_PUSH;
} else if (!strcmp(argv[i], "-r")) {
// Note that this argument is not added to processedArgIndicies because it
// must be passed through to pm
is_reinstall = true;
} else if (!strcmp(argv[i], "--fastdeploy")) {
processedArgIndicies.push_back(i);
use_fastdeploy = true;
} else if (!strcmp(argv[i], "--no-fastdeploy")) {
processedArgIndicies.push_back(i);
use_fastdeploy = false;
} else if (!strcmp(argv[i], "--force-agent")) {
processedArgIndicies.push_back(i);
agent_update_strategy = FastDeploy_AgentUpdateAlways;
} else if (!strcmp(argv[i], "--date-check-agent")) {
processedArgIndicies.push_back(i);
agent_update_strategy = FastDeploy_AgentUpdateNewerTimeStamp;
} else if (!strcmp(argv[i], "--version-check-agent")) {
processedArgIndicies.push_back(i);
agent_update_strategy = FastDeploy_AgentUpdateDifferentVersion;
#ifndef _WIN32
} else if (!strcmp(argv[i], "--local-agent")) {
processedArgIndicies.push_back(i);
use_localagent = true;
#endif
}
}
if (installMode == INSTALL_DEFAULT) {
installMode = best_install_mode();
}
if (installMode == INSTALL_STREAM && best_install_mode() == INSTALL_PUSH) {
error_exit("Attempting to use streaming install on unsupported device");
}
#if defined(ENABLE_FASTDEPLOY)
if (use_fastdeploy == true && get_device_api_level() < kFastDeployMinApi) {
printf("Fast Deploy is only compatible with devices of API version %d or higher, "
"ignoring.\n",
kFastDeployMinApi);
use_fastdeploy = false;
}
#endif
std::vector<const char*> passthrough_argv;
for (int i = 0; i < argc; i++) {
if (std::find(processedArgIndicies.begin(), processedArgIndicies.end(), i) ==
processedArgIndicies.end()) {
passthrough_argv.push_back(argv[i]);
}
}
if (passthrough_argv.size() < 2) {
error_exit("install requires an apk argument");
}
if (use_fastdeploy == true) {
#if defined(ENABLE_FASTDEPLOY)
fastdeploy_set_local_agent(use_localagent);
update_agent(agent_update_strategy);
// The last argument must be the APK file
const char* file = passthrough_argv.back();
use_fastdeploy = find_package(file);
#else
error_exit("fastdeploy is disabled");
#endif
}
switch (installMode) {
case INSTALL_PUSH:
return install_app_legacy(passthrough_argv.size(), passthrough_argv.data(),
use_fastdeploy, use_localagent);
case INSTALL_STREAM:
return install_app_streamed(passthrough_argv.size(), passthrough_argv.data(),
use_fastdeploy, use_localagent);
case INSTALL_DEFAULT:
default:
return 1;
}
}
int install_multiple_app(int argc, const char** argv) {
// Find all APK arguments starting at end.
// All other arguments passed through verbatim.
int first_apk = -1;
uint64_t total_size = 0;
for (int i = argc - 1; i >= 0; i--) {
const char* file = argv[i];
if (android::base::EndsWithIgnoreCase(argv[i], ".apex")) {
error_exit("APEX packages are not compatible with install-multiple");
}
if (android::base::EndsWithIgnoreCase(file, ".apk") ||
android::base::EndsWithIgnoreCase(file, ".dm") ||
android::base::EndsWithIgnoreCase(file, ".fsv_sig")) {
struct stat sb;
if (stat(file, &sb) == -1) perror_exit("failed to stat \"%s\"", file);
total_size += sb.st_size;
first_apk = i;
} else {
break;
}
}
if (first_apk == -1) error_exit("need APK file on command line");
std::string install_cmd;
if (best_install_mode() == INSTALL_PUSH) {
install_cmd = "exec:pm";
} else {
install_cmd = "exec:cmd package";
}
std::string cmd = android::base::StringPrintf("%s install-create -S %" PRIu64,
install_cmd.c_str(), total_size);
for (int i = 1; i < first_apk; i++) {
cmd += " " + escape_arg(argv[i]);
}
// Create install session
std::string error;
char buf[BUFSIZ];
{
unique_fd fd(adb_connect(cmd, &error));
if (fd < 0) {
fprintf(stderr, "adb: connect error for create: %s\n", error.c_str());
return EXIT_FAILURE;
}
read_status_line(fd.get(), buf, sizeof(buf));
}
int session_id = -1;
if (!strncmp("Success", buf, 7)) {
char* start = strrchr(buf, '[');
char* end = strrchr(buf, ']');
if (start && end) {
*end = '\0';
session_id = strtol(start + 1, nullptr, 10);
}
}
if (session_id < 0) {
fprintf(stderr, "adb: failed to create session\n");
fputs(buf, stderr);
return EXIT_FAILURE;
}
// Valid session, now stream the APKs
bool success = true;
for (int i = first_apk; i < argc; i++) {
const char* file = argv[i];
struct stat sb;
if (stat(file, &sb) == -1) {
fprintf(stderr, "adb: failed to stat \"%s\": %s\n", file, strerror(errno));
success = false;
goto finalize_session;
}
std::string cmd =
android::base::StringPrintf("%s install-write -S %" PRIu64 " %d %s -",
install_cmd.c_str(), static_cast<uint64_t>(sb.st_size),
session_id, android::base::Basename(file).c_str());
unique_fd local_fd(adb_open(file, O_RDONLY | O_CLOEXEC));
if (local_fd < 0) {
fprintf(stderr, "adb: failed to open \"%s\": %s\n", file, strerror(errno));
success = false;
goto finalize_session;
}
std::string error;
unique_fd remote_fd(adb_connect(cmd, &error));
if (remote_fd < 0) {
fprintf(stderr, "adb: connect error for write: %s\n", error.c_str());
success = false;
goto finalize_session;
}
copy_to_file(local_fd.get(), remote_fd.get());
read_status_line(remote_fd.get(), buf, sizeof(buf));
if (strncmp("Success", buf, 7)) {
fprintf(stderr, "adb: failed to write \"%s\"\n", file);
fputs(buf, stderr);
success = false;
goto finalize_session;
}
}
finalize_session:
// Commit session if we streamed everything okay; otherwise abandon.
std::string service = android::base::StringPrintf("%s install-%s %d", install_cmd.c_str(),
success ? "commit" : "abandon", session_id);
{
unique_fd fd(adb_connect(service, &error));
if (fd < 0) {
fprintf(stderr, "adb: connect error for finalize: %s\n", error.c_str());
return EXIT_FAILURE;
}
read_status_line(fd.get(), buf, sizeof(buf));
}
if (!success) return EXIT_FAILURE;
if (strncmp("Success", buf, 7)) {
fprintf(stderr, "adb: failed to finalize session\n");
fputs(buf, stderr);
return EXIT_FAILURE;
}
fputs(buf, stdout);
return EXIT_SUCCESS;
}
int install_multi_package(int argc, const char** argv) {
// Find all APK arguments starting at end.
// All other arguments passed through verbatim.
bool apex_found = false;
int first_package = -1;
for (int i = argc - 1; i >= 0; i--) {
const char* file = argv[i];
if (android::base::EndsWithIgnoreCase(file, ".apk") ||
android::base::EndsWithIgnoreCase(file, ".apex")) {
first_package = i;
if (android::base::EndsWithIgnoreCase(file, ".apex")) {
apex_found = true;
}
} else {
break;
}
}
if (first_package == -1) error_exit("need APK or APEX files on command line");
if (best_install_mode() == INSTALL_PUSH) {
fprintf(stderr, "adb: multi-package install is not supported on this device\n");
return EXIT_FAILURE;
}
std::string install_cmd = "exec:cmd package";
std::string multi_package_cmd =
android::base::StringPrintf("%s install-create --multi-package", install_cmd.c_str());
for (int i = 1; i < first_package; i++) {
multi_package_cmd += " " + escape_arg(argv[i]);
}
if (apex_found) {
multi_package_cmd += " --staged";
}
// Create multi-package install session
std::string error;
char buf[BUFSIZ];
{
unique_fd fd(adb_connect(multi_package_cmd, &error));
if (fd < 0) {
fprintf(stderr, "adb: connect error for create multi-package: %s\n", error.c_str());
return EXIT_FAILURE;
}
read_status_line(fd.get(), buf, sizeof(buf));
}
int parent_session_id = -1;
if (!strncmp("Success", buf, 7)) {
char* start = strrchr(buf, '[');
char* end = strrchr(buf, ']');
if (start && end) {
*end = '\0';
parent_session_id = strtol(start + 1, nullptr, 10);
}
}
if (parent_session_id < 0) {
fprintf(stderr, "adb: failed to create multi-package session\n");
fputs(buf, stderr);
return EXIT_FAILURE;
}
fprintf(stdout, "Created parent session ID %d.\n", parent_session_id);
std::vector<int> session_ids;
// Valid session, now create the individual sessions and stream the APKs
int success = EXIT_FAILURE;
std::string individual_cmd =
android::base::StringPrintf("%s install-create", install_cmd.c_str());
std::string all_session_ids = "";
for (int i = 1; i < first_package; i++) {
individual_cmd += " " + escape_arg(argv[i]);
}
if (apex_found) {
individual_cmd += " --staged";
}
std::string individual_apex_cmd = individual_cmd + " --apex";
std::string cmd = "";
for (int i = first_package; i < argc; i++) {
const char* file = argv[i];
char buf[BUFSIZ];
{
unique_fd fd;
// Create individual install session
if (android::base::EndsWithIgnoreCase(file, ".apex")) {
fd.reset(adb_connect(individual_apex_cmd, &error));
} else {
fd.reset(adb_connect(individual_cmd, &error));
}
if (fd < 0) {
fprintf(stderr, "adb: connect error for create: %s\n", error.c_str());
goto finalize_multi_package_session;
}
read_status_line(fd.get(), buf, sizeof(buf));
}
int session_id = -1;
if (!strncmp("Success", buf, 7)) {
char* start = strrchr(buf, '[');
char* end = strrchr(buf, ']');
if (start && end) {
*end = '\0';
session_id = strtol(start + 1, nullptr, 10);
}
}
if (session_id < 0) {
fprintf(stderr, "adb: failed to create multi-package session\n");
fputs(buf, stderr);
goto finalize_multi_package_session;
}
fprintf(stdout, "Created child session ID %d.\n", session_id);
session_ids.push_back(session_id);
// Support splitAPKs by allowing the notation split1.apk:split2.apk:split3.apk as argument.
std::vector<std::string> splits = android::base::Split(file, ":");
for (const std::string& split : splits) {
struct stat sb;
if (stat(split.c_str(), &sb) == -1) {
fprintf(stderr, "adb: failed to stat %s: %s\n", split.c_str(), strerror(errno));
goto finalize_multi_package_session;
}
std::string cmd = android::base::StringPrintf(
"%s install-write -S %" PRIu64 " %d %d_%s -", install_cmd.c_str(),
static_cast<uint64_t>(sb.st_size), session_id, i,
android::base::Basename(split).c_str());
unique_fd local_fd(adb_open(split.c_str(), O_RDONLY | O_CLOEXEC));
if (local_fd < 0) {
fprintf(stderr, "adb: failed to open %s: %s\n", split.c_str(), strerror(errno));
goto finalize_multi_package_session;
}
std::string error;
unique_fd remote_fd(adb_connect(cmd, &error));
if (remote_fd < 0) {
fprintf(stderr, "adb: connect error for write: %s\n", error.c_str());
goto finalize_multi_package_session;
}
copy_to_file(local_fd.get(), remote_fd.get());
read_status_line(remote_fd.get(), buf, sizeof(buf));
if (strncmp("Success", buf, 7)) {
fprintf(stderr, "adb: failed to write %s\n", split.c_str());
fputs(buf, stderr);
goto finalize_multi_package_session;
}
}
all_session_ids += android::base::StringPrintf(" %d", session_id);
}
cmd = android::base::StringPrintf("%s install-add-session %d%s", install_cmd.c_str(),
parent_session_id, all_session_ids.c_str());
{
unique_fd fd(adb_connect(cmd, &error));
if (fd < 0) {
fprintf(stderr, "adb: connect error for install-add-session: %s\n", error.c_str());
goto finalize_multi_package_session;
}
read_status_line(fd.get(), buf, sizeof(buf));
}
if (strncmp("Success", buf, 7)) {
fprintf(stderr, "adb: failed to link sessions (%s)\n", cmd.c_str());
fputs(buf, stderr);
goto finalize_multi_package_session;
}
// no failures means we can proceed with the assumption of success
success = 0;
finalize_multi_package_session:
// Commit session if we streamed everything okay; otherwise abandon
std::string service =
android::base::StringPrintf("%s install-%s %d", install_cmd.c_str(),
success == 0 ? "commit" : "abandon", parent_session_id);
{
unique_fd fd(adb_connect(service, &error));
if (fd < 0) {
fprintf(stderr, "adb: connect error for finalize: %s\n", error.c_str());
return EXIT_FAILURE;
}
read_status_line(fd.get(), buf, sizeof(buf));
}
if (!strncmp("Success", buf, 7)) {
fputs(buf, stdout);
if (success == 0) {
return 0;
}
} else {
fprintf(stderr, "adb: failed to finalize session\n");
fputs(buf, stderr);
}
session_ids.push_back(parent_session_id);
// try to abandon all remaining sessions
for (std::size_t i = 0; i < session_ids.size(); i++) {
service = android::base::StringPrintf("%s install-abandon %d", install_cmd.c_str(),
session_ids[i]);
fprintf(stderr, "Attempting to abandon session ID %d\n", session_ids[i]);
unique_fd fd(adb_connect(service, &error));
if (fd < 0) {
fprintf(stderr, "adb: connect error for finalize: %s\n", error.c_str());
continue;
}
read_status_line(fd.get(), buf, sizeof(buf));
}
return EXIT_FAILURE;
}
int delete_device_file(const std::string& filename) {
// http://b/17339227 "Sideloading a Readonly File Results in a Prompt to
// Delete" caused us to add `-f` here, to avoid the equivalent of the `-i`
// prompt that you get from BSD rm (used in Android 5) if you have a
// non-writable file and stdin is a tty (which is true for old versions of
// adbd).
//
// Unfortunately, `rm -f` requires Android 4.3, so that workaround broke
// earlier Android releases. This was reported as http://b/37704384 "adb
// install -r passes invalid argument to rm on Android 4.1" and
// http://b/37035817 "ADB Fails: rm failed for -f, No such file or
// directory".
//
// Testing on a variety of devices and emulators shows that redirecting
// stdin is sufficient to avoid the pseudo-`-i`, and works on toolbox,
// BSD, and toybox versions of rm.
return send_shell_command("rm " + escape_arg(filename) + " </dev/null");
}