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 "base/linux_util.h"
6
7 #include <dirent.h>
8 #include <errno.h>
9 #include <fcntl.h>
10 #include <stdlib.h>
11 #include <sys/stat.h>
12 #include <sys/types.h>
13 #include <unistd.h>
14
15 #include <vector>
16
17 #include "base/command_line.h"
18 #include "base/file_util.h"
19 #include "base/memory/scoped_ptr.h"
20 #include "base/memory/singleton.h"
21 #include "base/path_service.h"
22 #include "base/process/launch.h"
23 #include "base/strings/string_util.h"
24 #include "base/synchronization/lock.h"
25
26 namespace {
27
28 // Not needed for OS_CHROMEOS.
29 #if defined(OS_LINUX)
30 enum LinuxDistroState {
31 STATE_DID_NOT_CHECK = 0,
32 STATE_CHECK_STARTED = 1,
33 STATE_CHECK_FINISHED = 2,
34 };
35
36 // Helper class for GetLinuxDistro().
37 class LinuxDistroHelper {
38 public:
39 // Retrieves the Singleton.
GetInstance()40 static LinuxDistroHelper* GetInstance() {
41 return Singleton<LinuxDistroHelper>::get();
42 }
43
44 // The simple state machine goes from:
45 // STATE_DID_NOT_CHECK -> STATE_CHECK_STARTED -> STATE_CHECK_FINISHED.
LinuxDistroHelper()46 LinuxDistroHelper() : state_(STATE_DID_NOT_CHECK) {}
~LinuxDistroHelper()47 ~LinuxDistroHelper() {}
48
49 // Retrieve the current state, if we're in STATE_DID_NOT_CHECK,
50 // we automatically move to STATE_CHECK_STARTED so nobody else will
51 // do the check.
State()52 LinuxDistroState State() {
53 base::AutoLock scoped_lock(lock_);
54 if (STATE_DID_NOT_CHECK == state_) {
55 state_ = STATE_CHECK_STARTED;
56 return STATE_DID_NOT_CHECK;
57 }
58 return state_;
59 }
60
61 // Indicate the check finished, move to STATE_CHECK_FINISHED.
CheckFinished()62 void CheckFinished() {
63 base::AutoLock scoped_lock(lock_);
64 DCHECK_EQ(STATE_CHECK_STARTED, state_);
65 state_ = STATE_CHECK_FINISHED;
66 }
67
68 private:
69 base::Lock lock_;
70 LinuxDistroState state_;
71 };
72 #endif // if defined(OS_LINUX)
73
74 } // namespace
75
76 namespace base {
77
78 // Account for the terminating null character.
79 static const int kDistroSize = 128 + 1;
80
81 // We use this static string to hold the Linux distro info. If we
82 // crash, the crash handler code will send this in the crash dump.
83 char g_linux_distro[kDistroSize] =
84 #if defined(OS_CHROMEOS)
85 "CrOS";
86 #elif defined(OS_ANDROID)
87 "Android";
88 #else // if defined(OS_LINUX)
89 "Unknown";
90 #endif
91
GetLinuxDistro()92 std::string GetLinuxDistro() {
93 #if defined(OS_CHROMEOS) || defined(OS_ANDROID)
94 return g_linux_distro;
95 #elif defined(OS_LINUX)
96 LinuxDistroHelper* distro_state_singleton = LinuxDistroHelper::GetInstance();
97 LinuxDistroState state = distro_state_singleton->State();
98 if (STATE_CHECK_FINISHED == state)
99 return g_linux_distro;
100 if (STATE_CHECK_STARTED == state)
101 return "Unknown"; // Don't wait for other thread to finish.
102 DCHECK_EQ(state, STATE_DID_NOT_CHECK);
103 // We do this check only once per process. If it fails, there's
104 // little reason to believe it will work if we attempt to run
105 // lsb_release again.
106 std::vector<std::string> argv;
107 argv.push_back("lsb_release");
108 argv.push_back("-d");
109 std::string output;
110 base::GetAppOutput(CommandLine(argv), &output);
111 if (output.length() > 0) {
112 // lsb_release -d should return: Description:<tab>Distro Info
113 const char field[] = "Description:\t";
114 if (output.compare(0, strlen(field), field) == 0) {
115 SetLinuxDistro(output.substr(strlen(field)));
116 }
117 }
118 distro_state_singleton->CheckFinished();
119 return g_linux_distro;
120 #else
121 NOTIMPLEMENTED();
122 return "Unknown";
123 #endif
124 }
125
SetLinuxDistro(const std::string & distro)126 void SetLinuxDistro(const std::string& distro) {
127 std::string trimmed_distro;
128 base::TrimWhitespaceASCII(distro, base::TRIM_ALL, &trimmed_distro);
129 base::strlcpy(g_linux_distro, trimmed_distro.c_str(), kDistroSize);
130 }
131
FindThreadIDWithSyscall(pid_t pid,const std::string & expected_data,bool * syscall_supported)132 pid_t FindThreadIDWithSyscall(pid_t pid, const std::string& expected_data,
133 bool* syscall_supported) {
134 char buf[256];
135 snprintf(buf, sizeof(buf), "/proc/%d/task", pid);
136
137 if (syscall_supported != NULL)
138 *syscall_supported = false;
139
140 DIR* task = opendir(buf);
141 if (!task) {
142 DLOG(WARNING) << "Cannot open " << buf;
143 return -1;
144 }
145
146 std::vector<pid_t> tids;
147 struct dirent* dent;
148 while ((dent = readdir(task))) {
149 char* endptr;
150 const unsigned long int tid_ul = strtoul(dent->d_name, &endptr, 10);
151 if (tid_ul == ULONG_MAX || *endptr)
152 continue;
153 tids.push_back(tid_ul);
154 }
155 closedir(task);
156
157 scoped_ptr<char[]> syscall_data(new char[expected_data.length()]);
158 for (std::vector<pid_t>::const_iterator
159 i = tids.begin(); i != tids.end(); ++i) {
160 const pid_t current_tid = *i;
161 snprintf(buf, sizeof(buf), "/proc/%d/task/%d/syscall", pid, current_tid);
162 int fd = open(buf, O_RDONLY);
163 if (fd < 0)
164 continue;
165 if (syscall_supported != NULL)
166 *syscall_supported = true;
167 bool read_ret = ReadFromFD(fd, syscall_data.get(), expected_data.length());
168 close(fd);
169 if (!read_ret)
170 continue;
171
172 if (0 == strncmp(expected_data.c_str(), syscall_data.get(),
173 expected_data.length())) {
174 return current_tid;
175 }
176 }
177 return -1;
178 }
179
180 } // namespace base
181