1 //===-- HostInfoLinux.cpp -------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "lldb/Host/linux/HostInfoLinux.h"
10 #include "lldb/Host/Config.h"
11 #include "lldb/Host/FileSystem.h"
12 #include "lldb/Utility/Log.h"
13 
14 #include "llvm/Support/Threading.h"
15 
16 #include <climits>
17 #include <cstdio>
18 #include <cstring>
19 #include <sys/utsname.h>
20 #include <unistd.h>
21 
22 #include <algorithm>
23 #include <mutex>
24 
25 using namespace lldb_private;
26 
27 namespace {
28 struct HostInfoLinuxFields {
29   llvm::once_flag m_distribution_once_flag;
30   std::string m_distribution_id;
31   llvm::once_flag m_os_version_once_flag;
32   llvm::VersionTuple m_os_version;
33 };
34 } // namespace
35 
36 static HostInfoLinuxFields *g_fields = nullptr;
37 
38 void HostInfoLinux::Initialize(SharedLibraryDirectoryHelper *helper) {
39   HostInfoPosix::Initialize(helper);
40 
41   g_fields = new HostInfoLinuxFields();
42 }
43 
44 void HostInfoLinux::Terminate() {
45   assert(g_fields && "Missing call to Initialize?");
46   delete g_fields;
47   g_fields = nullptr;
48   HostInfoBase::Terminate();
49 }
50 
51 llvm::VersionTuple HostInfoLinux::GetOSVersion() {
52   assert(g_fields && "Missing call to Initialize?");
53   llvm::call_once(g_fields->m_os_version_once_flag, []() {
54     struct utsname un;
55     if (uname(&un) != 0)
56       return;
57 
58     llvm::StringRef release = un.release;
59     // The kernel release string can include a lot of stuff (e.g.
60     // 4.9.0-6-amd64). We're only interested in the numbered prefix.
61     release = release.substr(0, release.find_first_not_of("0123456789."));
62     g_fields->m_os_version.tryParse(release);
63   });
64 
65   return g_fields->m_os_version;
66 }
67 
68 llvm::Optional<std::string> HostInfoLinux::GetOSBuildString() {
69   struct utsname un;
70   ::memset(&un, 0, sizeof(utsname));
71 
72   if (uname(&un) < 0)
73     return llvm::None;
74 
75   return std::string(un.release);
76 }
77 
78 llvm::StringRef HostInfoLinux::GetDistributionId() {
79   assert(g_fields && "Missing call to Initialize?");
80   // Try to run 'lbs_release -i', and use that response for the distribution
81   // id.
82   llvm::call_once(g_fields->m_distribution_once_flag, []() {
83     Log *log = GetLog(LLDBLog::Host);
84     LLDB_LOGF(log, "attempting to determine Linux distribution...");
85 
86     // check if the lsb_release command exists at one of the following paths
87     const char *const exe_paths[] = {"/bin/lsb_release",
88                                      "/usr/bin/lsb_release"};
89 
90     for (size_t exe_index = 0;
91          exe_index < sizeof(exe_paths) / sizeof(exe_paths[0]); ++exe_index) {
92       const char *const get_distribution_info_exe = exe_paths[exe_index];
93       if (access(get_distribution_info_exe, F_OK)) {
94         // this exe doesn't exist, move on to next exe
95         LLDB_LOGF(log, "executable doesn't exist: %s",
96                   get_distribution_info_exe);
97         continue;
98       }
99 
100       // execute the distribution-retrieval command, read output
101       std::string get_distribution_id_command(get_distribution_info_exe);
102       get_distribution_id_command += " -i";
103 
104       FILE *file = popen(get_distribution_id_command.c_str(), "r");
105       if (!file) {
106         LLDB_LOGF(log,
107                   "failed to run command: \"%s\", cannot retrieve "
108                   "platform information",
109                   get_distribution_id_command.c_str());
110         break;
111       }
112 
113       // retrieve the distribution id string.
114       char distribution_id[256] = {'\0'};
115       if (fgets(distribution_id, sizeof(distribution_id) - 1, file) !=
116           nullptr) {
117         LLDB_LOGF(log, "distribution id command returned \"%s\"",
118                   distribution_id);
119 
120         const char *const distributor_id_key = "Distributor ID:\t";
121         if (strstr(distribution_id, distributor_id_key)) {
122           // strip newlines
123           std::string id_string(distribution_id + strlen(distributor_id_key));
124           id_string.erase(std::remove(id_string.begin(), id_string.end(), '\n'),
125                           id_string.end());
126 
127           // lower case it and convert whitespace to underscores
128           std::transform(
129               id_string.begin(), id_string.end(), id_string.begin(),
130               [](char ch) { return tolower(isspace(ch) ? '_' : ch); });
131 
132           g_fields->m_distribution_id = id_string;
133           LLDB_LOGF(log, "distribution id set to \"%s\"",
134                     g_fields->m_distribution_id.c_str());
135         } else {
136           LLDB_LOGF(log, "failed to find \"%s\" field in \"%s\"",
137                     distributor_id_key, distribution_id);
138         }
139       } else {
140         LLDB_LOGF(log,
141                   "failed to retrieve distribution id, \"%s\" returned no"
142                   " lines",
143                   get_distribution_id_command.c_str());
144       }
145 
146       // clean up the file
147       pclose(file);
148     }
149   });
150 
151   return g_fields->m_distribution_id;
152 }
153 
154 FileSpec HostInfoLinux::GetProgramFileSpec() {
155   static FileSpec g_program_filespec;
156 
157   if (!g_program_filespec) {
158     char exe_path[PATH_MAX];
159     ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path) - 1);
160     if (len > 0) {
161       exe_path[len] = 0;
162       g_program_filespec.SetFile(exe_path, FileSpec::Style::native);
163     }
164   }
165 
166   return g_program_filespec;
167 }
168 
169 bool HostInfoLinux::ComputeSupportExeDirectory(FileSpec &file_spec) {
170   if (HostInfoPosix::ComputeSupportExeDirectory(file_spec) &&
171       file_spec.IsAbsolute() && FileSystem::Instance().Exists(file_spec))
172     return true;
173   file_spec.GetDirectory() = GetProgramFileSpec().GetDirectory();
174   return !file_spec.GetDirectory().IsEmpty();
175 }
176 
177 bool HostInfoLinux::ComputeSystemPluginsDirectory(FileSpec &file_spec) {
178   FileSpec temp_file("/usr/lib" LLDB_LIBDIR_SUFFIX "/lldb/plugins");
179   FileSystem::Instance().Resolve(temp_file);
180   file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
181   return true;
182 }
183 
184 bool HostInfoLinux::ComputeUserPluginsDirectory(FileSpec &file_spec) {
185   // XDG Base Directory Specification
186   // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html If
187   // XDG_DATA_HOME exists, use that, otherwise use ~/.local/share/lldb.
188   const char *xdg_data_home = getenv("XDG_DATA_HOME");
189   if (xdg_data_home && xdg_data_home[0]) {
190     std::string user_plugin_dir(xdg_data_home);
191     user_plugin_dir += "/lldb";
192     file_spec.GetDirectory().SetCString(user_plugin_dir.c_str());
193   } else
194     file_spec.GetDirectory().SetCString("~/.local/share/lldb");
195   return true;
196 }
197 
198 void HostInfoLinux::ComputeHostArchitectureSupport(ArchSpec &arch_32,
199                                                    ArchSpec &arch_64) {
200   HostInfoPosix::ComputeHostArchitectureSupport(arch_32, arch_64);
201 
202   const char *distribution_id = GetDistributionId().data();
203 
204   // On Linux, "unknown" in the vendor slot isn't what we want for the default
205   // triple.  It's probably an artifact of config.guess.
206   if (arch_32.IsValid()) {
207     arch_32.SetDistributionId(distribution_id);
208     if (arch_32.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
209       arch_32.GetTriple().setVendorName(llvm::StringRef());
210   }
211   if (arch_64.IsValid()) {
212     arch_64.SetDistributionId(distribution_id);
213     if (arch_64.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
214       arch_64.GetTriple().setVendorName(llvm::StringRef());
215   }
216 }
217