1 // Copyright 2015 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 #ifndef SERVICES_SERVICE_MANAGER_ZYGOTE_HOST_ZYGOTE_COMMUNICATION_LINUX_H_
6 #define SERVICES_SERVICE_MANAGER_ZYGOTE_HOST_ZYGOTE_COMMUNICATION_LINUX_H_
7
8 #include <memory>
9 #include <set>
10 #include <string>
11 #include <vector>
12
13 #include <sys/types.h>
14
15 #include "base/callback.h"
16 #include "base/component_export.h"
17 #include "base/files/scoped_file.h"
18 #include "base/process/kill.h"
19 #include "base/process/launch.h"
20 #include "base/process/process_handle.h"
21 #include "base/synchronization/lock.h"
22
23 namespace base {
24 class Pickle;
25 } // namespace base
26
27 namespace service_manager {
28
29 // Handles interprocess communication with the Linux zygote process. The zygote
30 // does not use standard Chrome IPC or mojo, see:
31 // https://chromium.googlesource.com/chromium/src/+/master/docs/linux/sandbox_ipc.md
COMPONENT_EXPORT(SERVICE_MANAGER_ZYGOTE)32 class COMPONENT_EXPORT(SERVICE_MANAGER_ZYGOTE) ZygoteCommunication {
33 public:
34 enum class ZygoteType { kSandboxed, kUnsandboxed };
35 explicit ZygoteCommunication(ZygoteType type);
36 ~ZygoteCommunication();
37
38 void Init(
39 base::OnceCallback<pid_t(base::CommandLine*, base::ScopedFD*)> launcher);
40
41 // Tries to start a process of type indicated by process_type.
42 // Returns its pid on success, otherwise base::kNullProcessHandle;
43 pid_t ForkRequest(const std::vector<std::string>& command_line,
44 const base::FileHandleMappingVector& mapping,
45 const std::string& process_type);
46
47 void EnsureProcessTerminated(pid_t process);
48
49 // Should be called every time a Zygote child died.
50 void ZygoteChildDied(pid_t process);
51
52 // Get the termination status (and, optionally, the exit code) of
53 // the process. |exit_code| is set to the exit code of the child
54 // process. (|exit_code| may be NULL.)
55 // Unfortunately the Zygote can not accurately figure out if a process
56 // is already dead without waiting synchronously for it.
57 // |known_dead| should be set to true when we already know that the process
58 // is dead. When |known_dead| is false, processes could be seen as
59 // still running, even when they're not. When |known_dead| is true, the
60 // process will be SIGKILL-ed first (which should have no effect if it was
61 // really dead). This is to prevent a waiting waitpid() from blocking in
62 // a single-threaded Zygote. See https://crbug.com/157458.
63 base::TerminationStatus GetTerminationStatus(base::ProcessHandle handle,
64 bool known_dead,
65 int* exit_code);
66
67 // Returns the sandbox status of this zygote.
68 int GetSandboxStatus();
69
70 private:
71 // Should be called every time a Zygote child is born.
72 void ZygoteChildBorn(pid_t process);
73
74 // Read the reply from the zygote.
75 ssize_t ReadReply(void* buf, size_t buf_len);
76
77 // Sends |data| to the zygote via |control_fd_|. If |fds| is non-NULL, the
78 // included file descriptors will also be passed. The caller is responsible
79 // for acquiring |control_lock_|.
80 bool SendMessage(const base::Pickle& data, const std::vector<int>* fds);
81
82 // Get the sandbox status from the zygote.
83 ssize_t ReadSandboxStatus();
84
85 // Indicates whether the Zygote starts unsandboxed or not.
86 const ZygoteType type_;
87
88 base::ScopedFD control_fd_; // the socket to the zygote.
89 // A lock protecting all communication with the zygote. This lock must be
90 // acquired before sending a command and released after the result has been
91 // received.
92 base::Lock control_lock_;
93 // The pid of the zygote.
94 pid_t pid_;
95 // The list of running zygote children.
96 std::set<pid_t> list_of_running_zygote_children_;
97 // The lock to guard the list of running zygote children.
98 base::Lock child_tracking_lock_;
99 int sandbox_status_;
100 bool have_read_sandbox_status_word_;
101 // Set to true when the zygote is initialized successfully.
102 bool init_;
103 };
104
105 } // namespace service_manager
106
107 #endif // SERVICES_SERVICE_MANAGER_ZYGOTE_HOST_ZYGOTE_COMMUNICATION_LINUX_H_
108