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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/renderer_host/render_sandbox_host_linux.h"
#include <stdint.h>
#include <unistd.h>
#include <sys/uio.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include "base/eintr_wrapper.h"
#include "base/process_util.h"
#include "base/logging.h"
#include "base/message_loop.h"
#include "base/pickle.h"
#include "base/unix_domain_socket_posix.h"
#include "SkFontHost_fontconfig_direct.h"
#include "SkFontHost_fontconfig_ipc.h"
// http://code.google.com/p/chromium/wiki/LinuxSandboxIPC
// BEWARE: code in this file run across *processes* (not just threads).
// This code runs in a child process
class SandboxIPCProcess {
public:
// lifeline_fd: this is the read end of a pipe which the browser process
// holds the other end of. If the browser process dies, it's descriptors are
// closed and we will noticed an EOF on the pipe. That's our signal to exit.
// browser_socket: the 'browser's end of the sandbox IPC socketpair. From the
// point of view of the renderer's, it's talking to the browser but this
// object actually services the requests.
SandboxIPCProcess(int lifeline_fd, int browser_socket)
: lifeline_fd_(lifeline_fd),
browser_socket_(browser_socket),
font_config_(new FontConfigDirect()) {
base::InjectiveMultimap multimap;
multimap.push_back(base::InjectionArc(0, lifeline_fd, false));
multimap.push_back(base::InjectionArc(0, browser_socket, false));
base::CloseSuperfluousFds(multimap);
}
void Run() {
struct pollfd pfds[2];
pfds[0].fd = lifeline_fd_;
pfds[0].events = POLLIN;
pfds[1].fd = browser_socket_;
pfds[1].events = POLLIN;
bool failed_polls = 0;
for (;;) {
const int r = HANDLE_EINTR(poll(pfds, 2, -1));
if (r < 1) {
LOG(WARNING) << "poll errno:" << errno;
if (failed_polls++ == 3) {
LOG(FATAL) << "poll failing. Sandbox host aborting.";
return;
}
continue;
}
failed_polls = 0;
if (pfds[0].revents) {
// our parent died so we should too.
_exit(0);
}
if (pfds[1].revents) {
HandleRequestFromRenderer(browser_socket_);
}
}
}
private:
// ---------------------------------------------------------------------------
// Requests from the renderer...
void HandleRequestFromRenderer(int fd) {
std::vector<int> fds;
static const unsigned kMaxMessageLength = 2048;
char buf[kMaxMessageLength];
const ssize_t len = base::RecvMsg(fd, buf, sizeof(buf), &fds);
if (len == -1)
return;
if (fds.size() == 0)
return;
Pickle pickle(buf, len);
void* iter = NULL;
int kind;
if (!pickle.ReadInt(&iter, &kind))
goto error;
if (kind == FontConfigIPC::METHOD_MATCH) {
HandleFontMatchRequest(fd, pickle, iter, fds);
} else if (kind == FontConfigIPC::METHOD_OPEN) {
HandleFontOpenRequest(fd, pickle, iter, fds);
}
error:
for (std::vector<int>::const_iterator
i = fds.begin(); i != fds.end(); ++i) {
close(*i);
}
}
void HandleFontMatchRequest(int fd, Pickle& pickle, void* iter,
std::vector<int>& fds) {
bool fileid_valid;
uint32_t fileid;
bool is_bold, is_italic;
std::string family;
if (!pickle.ReadBool(&iter, &fileid_valid))
return;
if (fileid_valid) {
if (!pickle.ReadUInt32(&iter, &fileid))
return;
}
if (!pickle.ReadBool(&iter, &is_bold) ||
!pickle.ReadBool(&iter, &is_italic) ||
!pickle.ReadString(&iter, &family)) {
return;
}
std::string result_family;
unsigned result_fileid;
const bool r = font_config_->Match(
&result_family, &result_fileid, fileid_valid, fileid, family, is_bold,
is_italic);
Pickle reply;
if (!r) {
reply.WriteBool(false);
} else {
reply.WriteBool(true);
reply.WriteUInt32(result_fileid);
reply.WriteString(result_family);
}
SendRendererReply(fds, reply, -1);
}
void HandleFontOpenRequest(int fd, Pickle& pickle, void* iter,
std::vector<int>& fds) {
uint32_t fileid;
if (!pickle.ReadUInt32(&iter, &fileid))
return;
const int result_fd = font_config_->Open(fileid);
Pickle reply;
if (result_fd == -1) {
reply.WriteBool(false);
} else {
reply.WriteBool(true);
}
SendRendererReply(fds, reply, result_fd);
}
void SendRendererReply(const std::vector<int>& fds, const Pickle& reply,
int reply_fd) {
struct msghdr msg;
memset(&msg, 0, sizeof(msg));
struct iovec iov = {const_cast<void*>(reply.data()), reply.size()};
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
char control_buffer[CMSG_SPACE(sizeof(int))];
if (reply_fd != -1) {
struct cmsghdr *cmsg;
msg.msg_control = control_buffer;
msg.msg_controllen = sizeof(control_buffer);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
memcpy(CMSG_DATA(cmsg), &reply_fd, sizeof(int));
msg.msg_controllen = cmsg->cmsg_len;
}
HANDLE_EINTR(sendmsg(fds[0], &msg, MSG_DONTWAIT));
}
// ---------------------------------------------------------------------------
const int lifeline_fd_;
const int browser_socket_;
FontConfigDirect* const font_config_;
};
// -----------------------------------------------------------------------------
// Runs on the main thread at startup.
RenderSandboxHostLinux::RenderSandboxHostLinux() {
int fds[2];
CHECK(socketpair(AF_UNIX, SOCK_DGRAM, 0, fds) == 0);
renderer_socket_ = fds[0];
const int browser_socket = fds[1];
int pipefds[2];
CHECK(0 == pipe(pipefds));
const int child_lifeline_fd = pipefds[0];
childs_lifeline_fd_ = pipefds[1];
const pid_t child = fork();
if (child == 0) {
SandboxIPCProcess handler(child_lifeline_fd, browser_socket);
handler.Run();
_exit(0);
}
}
RenderSandboxHostLinux::~RenderSandboxHostLinux() {
HANDLE_EINTR(close(renderer_socket_));
HANDLE_EINTR(close(childs_lifeline_fd_));
}
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