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 bool HostInfoLinux::GetOSKernelDescription(std::string &s) {
79   struct utsname un;
80 
81   ::memset(&un, 0, sizeof(utsname));
82   s.clear();
83 
84   if (uname(&un) < 0)
85     return false;
86 
87   s.assign(un.version);
88   return true;
89 }
90 
91 llvm::StringRef HostInfoLinux::GetDistributionId() {
92   assert(g_fields && "Missing call to Initialize?");
93   // Try to run 'lbs_release -i', and use that response for the distribution
94   // id.
95   llvm::call_once(g_fields->m_distribution_once_flag, []() {
96 
97     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST));
98     LLDB_LOGF(log, "attempting to determine Linux distribution...");
99 
100     // check if the lsb_release command exists at one of the following paths
101     const char *const exe_paths[] = {"/bin/lsb_release",
102                                      "/usr/bin/lsb_release"};
103 
104     for (size_t exe_index = 0;
105          exe_index < sizeof(exe_paths) / sizeof(exe_paths[0]); ++exe_index) {
106       const char *const get_distribution_info_exe = exe_paths[exe_index];
107       if (access(get_distribution_info_exe, F_OK)) {
108         // this exe doesn't exist, move on to next exe
109         LLDB_LOGF(log, "executable doesn't exist: %s",
110                   get_distribution_info_exe);
111         continue;
112       }
113 
114       // execute the distribution-retrieval command, read output
115       std::string get_distribution_id_command(get_distribution_info_exe);
116       get_distribution_id_command += " -i";
117 
118       FILE *file = popen(get_distribution_id_command.c_str(), "r");
119       if (!file) {
120         LLDB_LOGF(log,
121                   "failed to run command: \"%s\", cannot retrieve "
122                   "platform information",
123                   get_distribution_id_command.c_str());
124         break;
125       }
126 
127       // retrieve the distribution id string.
128       char distribution_id[256] = {'\0'};
129       if (fgets(distribution_id, sizeof(distribution_id) - 1, file) !=
130           nullptr) {
131         LLDB_LOGF(log, "distribution id command returned \"%s\"",
132                   distribution_id);
133 
134         const char *const distributor_id_key = "Distributor ID:\t";
135         if (strstr(distribution_id, distributor_id_key)) {
136           // strip newlines
137           std::string id_string(distribution_id + strlen(distributor_id_key));
138           id_string.erase(std::remove(id_string.begin(), id_string.end(), '\n'),
139                           id_string.end());
140 
141           // lower case it and convert whitespace to underscores
142           std::transform(
143               id_string.begin(), id_string.end(), id_string.begin(),
144               [](char ch) { return tolower(isspace(ch) ? '_' : ch); });
145 
146           g_fields->m_distribution_id = id_string;
147           LLDB_LOGF(log, "distribution id set to \"%s\"",
148                     g_fields->m_distribution_id.c_str());
149         } else {
150           LLDB_LOGF(log, "failed to find \"%s\" field in \"%s\"",
151                     distributor_id_key, distribution_id);
152         }
153       } else {
154         LLDB_LOGF(log,
155                   "failed to retrieve distribution id, \"%s\" returned no"
156                   " lines",
157                   get_distribution_id_command.c_str());
158       }
159 
160       // clean up the file
161       pclose(file);
162     }
163   });
164 
165   return g_fields->m_distribution_id;
166 }
167 
168 FileSpec HostInfoLinux::GetProgramFileSpec() {
169   static FileSpec g_program_filespec;
170 
171   if (!g_program_filespec) {
172     char exe_path[PATH_MAX];
173     ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path) - 1);
174     if (len > 0) {
175       exe_path[len] = 0;
176       g_program_filespec.SetFile(exe_path, FileSpec::Style::native);
177     }
178   }
179 
180   return g_program_filespec;
181 }
182 
183 bool HostInfoLinux::ComputeSupportExeDirectory(FileSpec &file_spec) {
184   if (HostInfoPosix::ComputeSupportExeDirectory(file_spec) &&
185       file_spec.IsAbsolute() && FileSystem::Instance().Exists(file_spec))
186     return true;
187   file_spec.GetDirectory() = GetProgramFileSpec().GetDirectory();
188   return !file_spec.GetDirectory().IsEmpty();
189 }
190 
191 bool HostInfoLinux::ComputeSystemPluginsDirectory(FileSpec &file_spec) {
192   FileSpec temp_file("/usr/lib" LLDB_LIBDIR_SUFFIX "/lldb/plugins");
193   FileSystem::Instance().Resolve(temp_file);
194   file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
195   return true;
196 }
197 
198 bool HostInfoLinux::ComputeUserPluginsDirectory(FileSpec &file_spec) {
199   // XDG Base Directory Specification
200   // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html If
201   // XDG_DATA_HOME exists, use that, otherwise use ~/.local/share/lldb.
202   const char *xdg_data_home = getenv("XDG_DATA_HOME");
203   if (xdg_data_home && xdg_data_home[0]) {
204     std::string user_plugin_dir(xdg_data_home);
205     user_plugin_dir += "/lldb";
206     file_spec.GetDirectory().SetCString(user_plugin_dir.c_str());
207   } else
208     file_spec.GetDirectory().SetCString("~/.local/share/lldb");
209   return true;
210 }
211 
212 void HostInfoLinux::ComputeHostArchitectureSupport(ArchSpec &arch_32,
213                                                    ArchSpec &arch_64) {
214   HostInfoPosix::ComputeHostArchitectureSupport(arch_32, arch_64);
215 
216   const char *distribution_id = GetDistributionId().data();
217 
218   // On Linux, "unknown" in the vendor slot isn't what we want for the default
219   // triple.  It's probably an artifact of config.guess.
220   if (arch_32.IsValid()) {
221     arch_32.SetDistributionId(distribution_id);
222     if (arch_32.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
223       arch_32.GetTriple().setVendorName(llvm::StringRef());
224   }
225   if (arch_64.IsValid()) {
226     arch_64.SetDistributionId(distribution_id);
227     if (arch_64.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
228       arch_64.GetTriple().setVendorName(llvm::StringRef());
229   }
230 }
231