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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/system/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 "mojo/system/embedder/platform_handle.h" | |
17 | |
18 namespace mojo { | |
19 namespace embedder { | |
20 | |
21 namespace { | |
22 | |
23 bool IsTargetDescriptorUsed( | |
24 const base::FileHandleMappingVector& file_handle_mapping, | |
25 int target_fd) { | |
26 for (size_t i = 0; i < file_handle_mapping.size(); i++) { | |
27 if (file_handle_mapping[i].second == target_fd) | |
28 return true; | |
29 } | |
30 return false; | |
31 } | |
32 | |
33 } // namespace | |
34 | |
35 PlatformChannelPair::PlatformChannelPair() { | |
36 // Create the Unix domain socket and set the ends to nonblocking. | |
37 int fds[2]; | |
38 // TODO(vtl): Maybe fail gracefully if |socketpair()| fails. | |
39 PCHECK(socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0); | |
40 PCHECK(fcntl(fds[0], F_SETFL, O_NONBLOCK) == 0); | |
41 PCHECK(fcntl(fds[1], F_SETFL, O_NONBLOCK) == 0); | |
42 | |
43 server_handle_.reset(PlatformHandle(fds[0])); | |
44 DCHECK(server_handle_.is_valid()); | |
45 client_handle_.reset(PlatformHandle(fds[1])); | |
46 DCHECK(client_handle_.is_valid()); | |
47 } | |
48 | |
49 // static | |
50 ScopedPlatformHandle PlatformChannelPair::PassClientHandleFromParentProcess( | |
51 const CommandLine& command_line) { | |
52 std::string client_fd_string = | |
53 command_line.GetSwitchValueASCII(kMojoPlatformChannelHandleSwitch); | |
54 int client_fd = -1; | |
55 if (client_fd_string.empty() || | |
56 !base::StringToInt(client_fd_string, &client_fd) || | |
57 client_fd < base::GlobalDescriptors::kBaseDescriptor) { | |
58 LOG(ERROR) << "Missing or invalid --" << kMojoPlatformChannelHandleSwitch; | |
59 return ScopedPlatformHandle(); | |
60 } | |
61 | |
62 return ScopedPlatformHandle(PlatformHandle(client_fd)); | |
63 } | |
64 | |
65 void PlatformChannelPair::PrepareToPassClientHandleToChildProcess( | |
66 CommandLine* command_line, | |
67 base::FileHandleMappingVector* handle_passing_info) const { | |
68 DCHECK(command_line); | |
69 DCHECK(handle_passing_info); | |
70 // This is an arbitrary sanity check. (Note that this guarantees that the loop | |
71 // below will terminate sanely.) | |
72 CHECK_LT(handle_passing_info->size(), 1000u); | |
73 | |
74 DCHECK(client_handle_.is_valid()); | |
75 | |
76 // Find a suitable FD to map our client handle to in the child process. | |
77 // This has quadratic time complexity in the size of |*handle_passing_info|, | |
78 // but |*handle_passing_info| should be very small (usually/often empty). | |
79 int target_fd = base::GlobalDescriptors::kBaseDescriptor; | |
80 while (IsTargetDescriptorUsed(*handle_passing_info, target_fd)) | |
81 target_fd++; | |
82 | |
83 handle_passing_info->push_back(std::pair<int, int>(client_handle_.get().fd, | |
84 target_fd)); | |
85 // Log a warning if the command line already has the switch, but "clobber" it | |
86 // anyway, since it's reasonably likely that all the switches were just copied | |
87 // from the parent. | |
88 LOG_IF(WARNING, command_line->HasSwitch(kMojoPlatformChannelHandleSwitch)) | |
89 << "Child command line already has switch --" | |
90 << kMojoPlatformChannelHandleSwitch << "=" | |
91 << command_line->GetSwitchValueASCII(kMojoPlatformChannelHandleSwitch); | |
92 // (Any existing switch won't actually be removed from the command line, but | |
93 // the last one appended takes precedence.) | |
94 command_line->AppendSwitchASCII(kMojoPlatformChannelHandleSwitch, | |
95 base::IntToString(target_fd)); | |
96 } | |
97 | |
98 } // namespace embedder | |
99 } // namespace mojo | |
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