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/LLDBLog.h"
13 #include "lldb/Utility/Log.h"
14 
15 #include "llvm/Support/Threading.h"
16 
17 #include <climits>
18 #include <cstdio>
19 #include <cstring>
20 #include <sys/utsname.h>
21 #include <unistd.h>
22 
23 #include <algorithm>
24 #include <mutex>
25 
26 using namespace lldb_private;
27 
28 namespace {
29 struct HostInfoLinuxFields {
30   llvm::once_flag m_distribution_once_flag;
31   std::string m_distribution_id;
32   llvm::once_flag m_os_version_once_flag;
33   llvm::VersionTuple m_os_version;
34 };
35 } // namespace
36 
37 static HostInfoLinuxFields *g_fields = nullptr;
38 
39 void HostInfoLinux::Initialize(SharedLibraryDirectoryHelper *helper) {
40   HostInfoPosix::Initialize(helper);
41 
42   g_fields = new HostInfoLinuxFields();
43 }
44 
45 void HostInfoLinux::Terminate() {
46   assert(g_fields && "Missing call to Initialize?");
47   delete g_fields;
48   g_fields = nullptr;
49   HostInfoBase::Terminate();
50 }
51 
52 llvm::VersionTuple HostInfoLinux::GetOSVersion() {
53   assert(g_fields && "Missing call to Initialize?");
54   llvm::call_once(g_fields->m_os_version_once_flag, []() {
55     struct utsname un;
56     if (uname(&un) != 0)
57       return;
58 
59     llvm::StringRef release = un.release;
60     // The kernel release string can include a lot of stuff (e.g.
61     // 4.9.0-6-amd64). We're only interested in the numbered prefix.
62     release = release.substr(0, release.find_first_not_of("0123456789."));
63     g_fields->m_os_version.tryParse(release);
64   });
65 
66   return g_fields->m_os_version;
67 }
68 
69 llvm::Optional<std::string> HostInfoLinux::GetOSBuildString() {
70   struct utsname un;
71   ::memset(&un, 0, sizeof(utsname));
72 
73   if (uname(&un) < 0)
74     return llvm::None;
75 
76   return std::string(un.release);
77 }
78 
79 llvm::StringRef HostInfoLinux::GetDistributionId() {
80   assert(g_fields && "Missing call to Initialize?");
81   // Try to run 'lbs_release -i', and use that response for the distribution
82   // id.
83   llvm::call_once(g_fields->m_distribution_once_flag, []() {
84     Log *log = GetLog(LLDBLog::Host);
85     LLDB_LOGF(log, "attempting to determine Linux distribution...");
86 
87     // check if the lsb_release command exists at one of the following paths
88     const char *const exe_paths[] = {"/bin/lsb_release",
89                                      "/usr/bin/lsb_release"};
90 
91     for (size_t exe_index = 0;
92          exe_index < sizeof(exe_paths) / sizeof(exe_paths[0]); ++exe_index) {
93       const char *const get_distribution_info_exe = exe_paths[exe_index];
94       if (access(get_distribution_info_exe, F_OK)) {
95         // this exe doesn't exist, move on to next exe
96         LLDB_LOGF(log, "executable doesn't exist: %s",
97                   get_distribution_info_exe);
98         continue;
99       }
100 
101       // execute the distribution-retrieval command, read output
102       std::string get_distribution_id_command(get_distribution_info_exe);
103       get_distribution_id_command += " -i";
104 
105       FILE *file = popen(get_distribution_id_command.c_str(), "r");
106       if (!file) {
107         LLDB_LOGF(log,
108                   "failed to run command: \"%s\", cannot retrieve "
109                   "platform information",
110                   get_distribution_id_command.c_str());
111         break;
112       }
113 
114       // retrieve the distribution id string.
115       char distribution_id[256] = {'\0'};
116       if (fgets(distribution_id, sizeof(distribution_id) - 1, file) !=
117           nullptr) {
118         LLDB_LOGF(log, "distribution id command returned \"%s\"",
119                   distribution_id);
120 
121         const char *const distributor_id_key = "Distributor ID:\t";
122         if (strstr(distribution_id, distributor_id_key)) {
123           // strip newlines
124           std::string id_string(distribution_id + strlen(distributor_id_key));
125           id_string.erase(std::remove(id_string.begin(), id_string.end(), '\n'),
126                           id_string.end());
127 
128           // lower case it and convert whitespace to underscores
129           std::transform(
130               id_string.begin(), id_string.end(), id_string.begin(),
131               [](char ch) { return tolower(isspace(ch) ? '_' : ch); });
132 
133           g_fields->m_distribution_id = id_string;
134           LLDB_LOGF(log, "distribution id set to \"%s\"",
135                     g_fields->m_distribution_id.c_str());
136         } else {
137           LLDB_LOGF(log, "failed to find \"%s\" field in \"%s\"",
138                     distributor_id_key, distribution_id);
139         }
140       } else {
141         LLDB_LOGF(log,
142                   "failed to retrieve distribution id, \"%s\" returned no"
143                   " lines",
144                   get_distribution_id_command.c_str());
145       }
146 
147       // clean up the file
148       pclose(file);
149     }
150   });
151 
152   return g_fields->m_distribution_id;
153 }
154 
155 FileSpec HostInfoLinux::GetProgramFileSpec() {
156   static FileSpec g_program_filespec;
157 
158   if (!g_program_filespec) {
159     char exe_path[PATH_MAX];
160     ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path) - 1);
161     if (len > 0) {
162       exe_path[len] = 0;
163       g_program_filespec.SetFile(exe_path, FileSpec::Style::native);
164     }
165   }
166 
167   return g_program_filespec;
168 }
169 
170 bool HostInfoLinux::ComputeSupportExeDirectory(FileSpec &file_spec) {
171   if (HostInfoPosix::ComputeSupportExeDirectory(file_spec) &&
172       file_spec.IsAbsolute() && FileSystem::Instance().Exists(file_spec))
173     return true;
174   file_spec.GetDirectory() = GetProgramFileSpec().GetDirectory();
175   return !file_spec.GetDirectory().IsEmpty();
176 }
177 
178 bool HostInfoLinux::ComputeSystemPluginsDirectory(FileSpec &file_spec) {
179   FileSpec temp_file("/usr/lib" LLDB_LIBDIR_SUFFIX "/lldb/plugins");
180   FileSystem::Instance().Resolve(temp_file);
181   file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
182   return true;
183 }
184 
185 bool HostInfoLinux::ComputeUserPluginsDirectory(FileSpec &file_spec) {
186   // XDG Base Directory Specification
187   // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html If
188   // XDG_DATA_HOME exists, use that, otherwise use ~/.local/share/lldb.
189   const char *xdg_data_home = getenv("XDG_DATA_HOME");
190   if (xdg_data_home && xdg_data_home[0]) {
191     std::string user_plugin_dir(xdg_data_home);
192     user_plugin_dir += "/lldb";
193     file_spec.GetDirectory().SetCString(user_plugin_dir.c_str());
194   } else
195     file_spec.GetDirectory().SetCString("~/.local/share/lldb");
196   return true;
197 }
198 
199 void HostInfoLinux::ComputeHostArchitectureSupport(ArchSpec &arch_32,
200                                                    ArchSpec &arch_64) {
201   HostInfoPosix::ComputeHostArchitectureSupport(arch_32, arch_64);
202 
203   const char *distribution_id = GetDistributionId().data();
204 
205   // On Linux, "unknown" in the vendor slot isn't what we want for the default
206   // triple.  It's probably an artifact of config.guess.
207   if (arch_32.IsValid()) {
208     arch_32.SetDistributionId(distribution_id);
209     if (arch_32.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
210       arch_32.GetTriple().setVendorName(llvm::StringRef());
211   }
212   if (arch_64.IsValid()) {
213     arch_64.SetDistributionId(distribution_id);
214     if (arch_64.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
215       arch_64.GetTriple().setVendorName(llvm::StringRef());
216   }
217 }
218