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1 // Copyright 2014 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "mojo/edk/embedder/platform_channel_pair.h" | |
6 | |
7 #include <fcntl.h> | |
8 #include <sys/socket.h> | |
9 #include <sys/types.h> | |
10 #include <unistd.h> | |
11 | |
12 #include "base/command_line.h" | |
13 #include "base/logging.h" | |
14 #include "base/posix/global_descriptors.h" | |
15 #include "base/strings/string_number_conversions.h" | |
16 #include "build/build_config.h" | |
17 #include "mojo/edk/embedder/platform_handle.h" | |
18 | |
19 namespace mojo { | |
20 namespace embedder { | |
21 | |
22 namespace { | |
23 | |
24 bool IsTargetDescriptorUsed( | |
25 const base::FileHandleMappingVector& file_handle_mapping, | |
26 int target_fd) { | |
27 for (size_t i = 0; i < file_handle_mapping.size(); i++) { | |
28 if (file_handle_mapping[i].second == target_fd) | |
29 return true; | |
30 } | |
31 return false; | |
32 } | |
33 | |
34 } // namespace | |
35 | |
36 PlatformChannelPair::PlatformChannelPair() { | |
37 // Create the Unix domain socket and set the ends to nonblocking. | |
38 int fds[2]; | |
39 // TODO(vtl): Maybe fail gracefully if |socketpair()| fails. | |
40 PCHECK(socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0); | |
41 PCHECK(fcntl(fds[0], F_SETFL, O_NONBLOCK) == 0); | |
42 PCHECK(fcntl(fds[1], F_SETFL, O_NONBLOCK) == 0); | |
43 | |
44 #if defined(OS_MACOSX) | |
45 // This turns off |SIGPIPE| when writing to a closed socket (causing it to | |
46 // fail with |EPIPE| instead). On Linux, we have to use |send...()| with | |
47 // |MSG_NOSIGNAL| -- which is not supported on Mac -- instead. | |
48 int no_sigpipe = 1; | |
49 PCHECK(setsockopt(fds[0], SOL_SOCKET, SO_NOSIGPIPE, &no_sigpipe, | |
50 sizeof(no_sigpipe)) == 0); | |
51 PCHECK(setsockopt(fds[1], SOL_SOCKET, SO_NOSIGPIPE, &no_sigpipe, | |
52 sizeof(no_sigpipe)) == 0); | |
53 #endif // defined(OS_MACOSX) | |
54 | |
55 server_handle_.reset(PlatformHandle(fds[0])); | |
56 DCHECK(server_handle_.is_valid()); | |
57 client_handle_.reset(PlatformHandle(fds[1])); | |
58 DCHECK(client_handle_.is_valid()); | |
59 } | |
60 | |
61 // static | |
62 ScopedPlatformHandle PlatformChannelPair::PassClientHandleFromParentProcess( | |
63 const base::CommandLine& command_line) { | |
64 std::string client_fd_string = | |
65 command_line.GetSwitchValueASCII(kMojoPlatformChannelHandleSwitch); | |
66 int client_fd = -1; | |
67 if (client_fd_string.empty() || | |
68 !base::StringToInt(client_fd_string, &client_fd) || | |
69 client_fd < base::GlobalDescriptors::kBaseDescriptor) { | |
70 LOG(ERROR) << "Missing or invalid --" << kMojoPlatformChannelHandleSwitch; | |
71 return ScopedPlatformHandle(); | |
72 } | |
73 | |
74 return ScopedPlatformHandle(PlatformHandle(client_fd)); | |
75 } | |
76 | |
77 void PlatformChannelPair::PrepareToPassClientHandleToChildProcess( | |
78 base::CommandLine* command_line, | |
79 base::FileHandleMappingVector* handle_passing_info) const { | |
80 DCHECK(command_line); | |
81 DCHECK(handle_passing_info); | |
82 // This is an arbitrary sanity check. (Note that this guarantees that the loop | |
83 // below will terminate sanely.) | |
84 CHECK_LT(handle_passing_info->size(), 1000u); | |
85 | |
86 DCHECK(client_handle_.is_valid()); | |
87 | |
88 // Find a suitable FD to map our client handle to in the child process. | |
89 // This has quadratic time complexity in the size of |*handle_passing_info|, | |
90 // but |*handle_passing_info| should be very small (usually/often empty). | |
91 int target_fd = base::GlobalDescriptors::kBaseDescriptor; | |
92 while (IsTargetDescriptorUsed(*handle_passing_info, target_fd)) | |
93 target_fd++; | |
94 | |
95 handle_passing_info->push_back( | |
96 std::pair<int, int>(client_handle_.get().fd, target_fd)); | |
97 // Log a warning if the command line already has the switch, but "clobber" it | |
98 // anyway, since it's reasonably likely that all the switches were just copied | |
99 // from the parent. | |
100 LOG_IF(WARNING, command_line->HasSwitch(kMojoPlatformChannelHandleSwitch)) | |
101 << "Child command line already has switch --" | |
102 << kMojoPlatformChannelHandleSwitch << "=" | |
103 << command_line->GetSwitchValueASCII(kMojoPlatformChannelHandleSwitch); | |
104 // (Any existing switch won't actually be removed from the command line, but | |
105 // the last one appended takes precedence.) | |
106 command_line->AppendSwitchASCII(kMojoPlatformChannelHandleSwitch, | |
107 base::IntToString(target_fd)); | |
108 } | |
109 | |
110 } // namespace embedder | |
111 } // namespace mojo | |
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