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// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/zygote_host_linux.h"
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "base/command_line.h"
#include "base/eintr_wrapper.h"
#include "base/linux_util.h"
#include "base/logging.h"
#include "base/path_service.h"
#include "base/pickle.h"
#include "base/process_util.h"
#include "base/string_util.h"
#include "base/unix_domain_socket_posix.h"
#include "chrome/browser/renderer_host/render_sandbox_host_linux.h"
#include "chrome/common/chrome_constants.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/process_watcher.h"
ZygoteHost::ZygoteHost()
: pid_(-1),
init_(false),
using_suid_sandbox_(false) {
}
ZygoteHost::~ZygoteHost() {
if (init_)
close(control_fd_);
}
void ZygoteHost::Init(const std::string& sandbox_cmd) {
DCHECK(!init_);
init_ = true;
FilePath chrome_path;
CHECK(PathService::Get(base::FILE_EXE, &chrome_path));
CommandLine cmd_line(chrome_path);
cmd_line.AppendSwitchWithValue(switches::kProcessType,
switches::kZygoteProcess);
int fds[2];
CHECK(socketpair(PF_UNIX, SOCK_SEQPACKET, 0, fds) == 0);
base::file_handle_mapping_vector fds_to_map;
fds_to_map.push_back(std::make_pair(fds[1], 3));
const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
if (browser_command_line.HasSwitch(switches::kZygoteCmdPrefix)) {
const std::wstring prefix =
browser_command_line.GetSwitchValue(switches::kZygoteCmdPrefix);
cmd_line.PrependWrapper(prefix);
}
// Append any switches from the browser process that need to be forwarded on
// to the zygote/renderers.
// Should this list be obtained from browser_render_process_host.cc?
if (browser_command_line.HasSwitch(switches::kAllowSandboxDebugging)) {
cmd_line.AppendSwitch(switches::kAllowSandboxDebugging);
}
if (browser_command_line.HasSwitch(switches::kLoggingLevel)) {
cmd_line.AppendSwitchWithValue(switches::kLoggingLevel,
browser_command_line.GetSwitchValueASCII(
switches::kLoggingLevel));
}
if (browser_command_line.HasSwitch(switches::kEnableLogging)) {
// Append with value to support --enable-logging=stderr.
cmd_line.AppendSwitchWithValue(switches::kEnableLogging,
browser_command_line.GetSwitchValueASCII(
switches::kEnableLogging));
}
if (browser_command_line.HasSwitch(switches::kDisableSeccompSandbox)) {
cmd_line.AppendSwitch(switches::kDisableSeccompSandbox);
}
sandbox_binary_ = sandbox_cmd.c_str();
// Start up the sandbox host process and get the file descriptor for the
// renderers to talk to it.
const int sfd = Singleton<RenderSandboxHostLinux>()->GetRendererSocket();
fds_to_map.push_back(std::make_pair(sfd, 5));
int dummy_fd = -1;
if (using_suid_sandbox_) {
dummy_fd = socket(PF_UNIX, SOCK_DGRAM, 0);
CHECK(dummy_fd >= 0);
fds_to_map.push_back(std::make_pair(dummy_fd, 7));
}
base::ProcessHandle process;
base::LaunchApp(cmd_line.argv(), fds_to_map, false, &process);
CHECK(process != -1) << "Failed to launch zygote process";
if (using_suid_sandbox_) {
// In the SUID sandbox, the real zygote is forked from the sandbox.
// We need to look for it.
// But first, wait for the zygote to tell us it's running.
// The sending code is in chrome/browser/zygote_main_linux.cc.
std::vector<int> fds_vec;
const int kExpectedLength = sizeof(kZygoteMagic);
char buf[kExpectedLength];
const ssize_t len = base::RecvMsg(fds[0], buf, sizeof(buf), &fds_vec);
CHECK(len == kExpectedLength) << "Incorrect zygote magic length";
CHECK(0 == strcmp(buf, kZygoteMagic)) << "Incorrect zygote magic";
std::string inode_output;
ino_t inode = 0;
// Figure out the inode for |dummy_fd|, close |dummy_fd| on our end,
// and find the zygote process holding |dummy_fd|.
if (base::FileDescriptorGetInode(&inode, dummy_fd)) {
close(dummy_fd);
std::vector<std::string> get_inode_cmdline;
get_inode_cmdline.push_back(sandbox_binary_);
get_inode_cmdline.push_back(base::kFindInodeSwitch);
get_inode_cmdline.push_back(Int64ToString(inode));
CommandLine get_inode_cmd(get_inode_cmdline);
if (base::GetAppOutput(get_inode_cmd, &inode_output)) {
StringToInt(inode_output, &pid_);
}
}
CHECK(pid_ > 0) << "Did not find zygote process (using sandbox binary "
<< sandbox_binary_ << ")";
if (process != pid_) {
// Reap the sandbox.
ProcessWatcher::EnsureProcessGetsReaped(process);
}
} else {
// Not using the SUID sandbox.
pid_ = process;
}
close(fds[1]);
control_fd_ = fds[0];
}
pid_t ZygoteHost::ForkRenderer(
const std::vector<std::string>& argv,
const base::GlobalDescriptors::Mapping& mapping) {
DCHECK(init_);
Pickle pickle;
pickle.WriteInt(kCmdFork);
pickle.WriteInt(argv.size());
for (std::vector<std::string>::const_iterator
i = argv.begin(); i != argv.end(); ++i)
pickle.WriteString(*i);
pickle.WriteInt(mapping.size());
std::vector<int> fds;
for (base::GlobalDescriptors::Mapping::const_iterator
i = mapping.begin(); i != mapping.end(); ++i) {
pickle.WriteUInt32(i->first);
fds.push_back(i->second);
}
if (!base::SendMsg(control_fd_, pickle.data(), pickle.size(), fds))
return base::kNullProcessHandle;
pid_t pid;
if (HANDLE_EINTR(read(control_fd_, &pid, sizeof(pid))) != sizeof(pid))
return base::kNullProcessHandle;
const int kRendererScore = 5;
if (using_suid_sandbox_) {
base::ProcessHandle sandbox_helper_process;
base::file_handle_mapping_vector dummy_map;
std::vector<std::string> adj_oom_score_cmdline;
adj_oom_score_cmdline.push_back(sandbox_binary_);
adj_oom_score_cmdline.push_back(base::kAdjustOOMScoreSwitch);
adj_oom_score_cmdline.push_back(Int64ToString(pid));
adj_oom_score_cmdline.push_back(IntToString(kRendererScore));
CommandLine adj_oom_score_cmd(adj_oom_score_cmdline);
if (base::LaunchApp(adj_oom_score_cmdline, dummy_map, false,
&sandbox_helper_process)) {
ProcessWatcher::EnsureProcessGetsReaped(sandbox_helper_process);
}
} else {
base::AdjustOOMScore(pid, kRendererScore);
}
return pid;
}
void ZygoteHost::EnsureProcessTerminated(pid_t process) {
DCHECK(init_);
Pickle pickle;
pickle.WriteInt(kCmdReap);
pickle.WriteInt(process);
HANDLE_EINTR(write(control_fd_, pickle.data(), pickle.size()));
}
bool ZygoteHost::DidProcessCrash(base::ProcessHandle handle,
bool* child_exited) {
DCHECK(init_);
Pickle pickle;
pickle.WriteInt(kCmdDidProcessCrash);
pickle.WriteInt(handle);
HANDLE_EINTR(write(control_fd_, pickle.data(), pickle.size()));
static const unsigned kMaxMessageLength = 128;
char buf[kMaxMessageLength];
const ssize_t len = HANDLE_EINTR(read(control_fd_, buf, sizeof(buf)));
if (len == -1) {
LOG(WARNING) << "Error reading message from zygote: " << errno;
return false;
} else if (len == 0) {
LOG(WARNING) << "Socket closed prematurely.";
return false;
}
Pickle read_pickle(buf, len);
bool did_crash, tmp_child_exited;
void* iter = NULL;
if (!read_pickle.ReadBool(&iter, &did_crash) ||
!read_pickle.ReadBool(&iter, &tmp_child_exited)) {
LOG(WARNING) << "Error parsing DidProcessCrash response from zygote.";
return false;
}
if (child_exited)
*child_exited = tmp_child_exited;
return did_crash;
}
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