1 // Copyright (c) 2012 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 "tools/android/common/daemon.h"
6
7 #include <errno.h>
8 #include <signal.h>
9 #include <stdio.h>
10 #include <sys/types.h>
11 #include <unistd.h>
12
13 #include "base/command_line.h"
14 #include "base/logging.h"
15
16 namespace {
17
18 const char kNoSpawnDaemon[] = "D";
19
20 int g_exit_status = 0;
21
Exit(int unused)22 void Exit(int unused) {
23 _exit(g_exit_status);
24 }
25
CloseFileDescriptor(int fd)26 void CloseFileDescriptor(int fd) {
27 int old_errno = errno;
28 close(fd);
29 errno = old_errno;
30 }
31
32 } // namespace
33
34 namespace tools {
35
HasHelpSwitch(const CommandLine & command_line)36 bool HasHelpSwitch(const CommandLine& command_line) {
37 return command_line.HasSwitch("h") || command_line.HasSwitch("help");
38 }
39
HasNoSpawnDaemonSwitch(const CommandLine & command_line)40 bool HasNoSpawnDaemonSwitch(const CommandLine& command_line) {
41 return command_line.HasSwitch(kNoSpawnDaemon);
42 }
43
ShowHelp(const char * program,const char * extra_title,const char * extra_descriptions)44 void ShowHelp(const char* program,
45 const char* extra_title,
46 const char* extra_descriptions) {
47 printf("Usage: %s [-%s] %s\n"
48 " -%s stops from spawning a daemon process\n%s",
49 program, kNoSpawnDaemon, extra_title, kNoSpawnDaemon,
50 extra_descriptions);
51 }
52
SpawnDaemon(int exit_status)53 void SpawnDaemon(int exit_status) {
54 g_exit_status = exit_status;
55 signal(SIGUSR1, Exit);
56
57 if (fork()) {
58 // In parent process.
59 sleep(10); // Wait for the child process to finish setsid().
60 NOTREACHED();
61 }
62
63 // In child process.
64 setsid(); // Detach the child process from its parent.
65 kill(getppid(), SIGUSR1); // Inform the parent process to exit.
66
67 // Close the standard input and outputs, otherwise the process may block
68 // adbd when the shell exits.
69 // Comment out these lines if you want to see outputs for debugging.
70 CloseFileDescriptor(0);
71 CloseFileDescriptor(1);
72 CloseFileDescriptor(2);
73 }
74
75 } // namespace tools
76