1 //===-- HostInfoLinux.cpp ---------------------------------------*- C++ -*-===//
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 <limits.h>
17 #include <stdio.h>
18 #include <string.h>
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   std::string m_distribution_id;
30   llvm::VersionTuple m_os_version;
31 };
32 
33 HostInfoLinuxFields *g_fields = nullptr;
34 }
35 
36 void HostInfoLinux::Initialize() {
37   HostInfoPosix::Initialize();
38 
39   g_fields = new HostInfoLinuxFields();
40 }
41 
42 llvm::VersionTuple HostInfoLinux::GetOSVersion() {
43   static llvm::once_flag g_once_flag;
44   llvm::call_once(g_once_flag, []() {
45     struct utsname un;
46     if (uname(&un) != 0)
47       return;
48 
49     llvm::StringRef release = un.release;
50     // The kernel release string can include a lot of stuff (e.g.
51     // 4.9.0-6-amd64). We're only interested in the numbered prefix.
52     release = release.substr(0, release.find_first_not_of("0123456789."));
53     g_fields->m_os_version.tryParse(release);
54   });
55 
56   return g_fields->m_os_version;
57 }
58 
59 bool HostInfoLinux::GetOSBuildString(std::string &s) {
60   struct utsname un;
61   ::memset(&un, 0, sizeof(utsname));
62   s.clear();
63 
64   if (uname(&un) < 0)
65     return false;
66 
67   s.assign(un.release);
68   return true;
69 }
70 
71 bool HostInfoLinux::GetOSKernelDescription(std::string &s) {
72   struct utsname un;
73 
74   ::memset(&un, 0, sizeof(utsname));
75   s.clear();
76 
77   if (uname(&un) < 0)
78     return false;
79 
80   s.assign(un.version);
81   return true;
82 }
83 
84 llvm::StringRef HostInfoLinux::GetDistributionId() {
85   // Try to run 'lbs_release -i', and use that response for the distribution
86   // id.
87   static llvm::once_flag g_once_flag;
88   llvm::call_once(g_once_flag, []() {
89 
90     Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_HOST));
91     if (log)
92       log->Printf("attempting to determine Linux distribution...");
93 
94     // check if the lsb_release command exists at one of the following paths
95     const char *const exe_paths[] = {"/bin/lsb_release",
96                                      "/usr/bin/lsb_release"};
97 
98     for (size_t exe_index = 0;
99          exe_index < sizeof(exe_paths) / sizeof(exe_paths[0]); ++exe_index) {
100       const char *const get_distribution_info_exe = exe_paths[exe_index];
101       if (access(get_distribution_info_exe, F_OK)) {
102         // this exe doesn't exist, move on to next exe
103         if (log)
104           log->Printf("executable doesn't exist: %s",
105                       get_distribution_info_exe);
106         continue;
107       }
108 
109       // execute the distribution-retrieval command, read output
110       std::string get_distribution_id_command(get_distribution_info_exe);
111       get_distribution_id_command += " -i";
112 
113       FILE *file = popen(get_distribution_id_command.c_str(), "r");
114       if (!file) {
115         if (log)
116           log->Printf("failed to run command: \"%s\", cannot retrieve "
117                       "platform information",
118                       get_distribution_id_command.c_str());
119         break;
120       }
121 
122       // retrieve the distribution id string.
123       char distribution_id[256] = {'\0'};
124       if (fgets(distribution_id, sizeof(distribution_id) - 1, file) !=
125           nullptr) {
126         if (log)
127           log->Printf("distribution id command returned \"%s\"",
128                       distribution_id);
129 
130         const char *const distributor_id_key = "Distributor ID:\t";
131         if (strstr(distribution_id, distributor_id_key)) {
132           // strip newlines
133           std::string id_string(distribution_id + strlen(distributor_id_key));
134           id_string.erase(std::remove(id_string.begin(), id_string.end(), '\n'),
135                           id_string.end());
136 
137           // lower case it and convert whitespace to underscores
138           std::transform(
139               id_string.begin(), id_string.end(), id_string.begin(),
140               [](char ch) { return tolower(isspace(ch) ? '_' : ch); });
141 
142           g_fields->m_distribution_id = id_string;
143           if (log)
144             log->Printf("distribution id set to \"%s\"",
145                         g_fields->m_distribution_id.c_str());
146         } else {
147           if (log)
148             log->Printf("failed to find \"%s\" field in \"%s\"",
149                         distributor_id_key, distribution_id);
150         }
151       } else {
152         if (log)
153           log->Printf("failed to retrieve distribution id, \"%s\" returned no"
154                       " lines",
155                       get_distribution_id_command.c_str());
156       }
157 
158       // clean up the file
159       pclose(file);
160     }
161   });
162 
163   return g_fields->m_distribution_id;
164 }
165 
166 FileSpec HostInfoLinux::GetProgramFileSpec() {
167   static FileSpec g_program_filespec;
168 
169   if (!g_program_filespec) {
170     char exe_path[PATH_MAX];
171     ssize_t len = readlink("/proc/self/exe", exe_path, sizeof(exe_path) - 1);
172     if (len > 0) {
173       exe_path[len] = 0;
174       g_program_filespec.SetFile(exe_path, FileSpec::Style::native);
175     }
176   }
177 
178   return g_program_filespec;
179 }
180 
181 bool HostInfoLinux::ComputeSupportExeDirectory(FileSpec &file_spec) {
182   if (HostInfoPosix::ComputeSupportExeDirectory(file_spec) &&
183       file_spec.IsAbsolute() && FileSystem::Instance().Exists(file_spec))
184     return true;
185   file_spec.GetDirectory() = GetProgramFileSpec().GetDirectory();
186   return !file_spec.GetDirectory().IsEmpty();
187 }
188 
189 bool HostInfoLinux::ComputeSystemPluginsDirectory(FileSpec &file_spec) {
190   FileSpec temp_file("/usr/lib" LLDB_LIBDIR_SUFFIX "/lldb/plugins");
191   FileSystem::Instance().Resolve(temp_file);
192   file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
193   return true;
194 }
195 
196 bool HostInfoLinux::ComputeUserPluginsDirectory(FileSpec &file_spec) {
197   // XDG Base Directory Specification
198   // http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html If
199   // XDG_DATA_HOME exists, use that, otherwise use ~/.local/share/lldb.
200   const char *xdg_data_home = getenv("XDG_DATA_HOME");
201   if (xdg_data_home && xdg_data_home[0]) {
202     std::string user_plugin_dir(xdg_data_home);
203     user_plugin_dir += "/lldb";
204     file_spec.GetDirectory().SetCString(user_plugin_dir.c_str());
205   } else
206     file_spec.GetDirectory().SetCString("~/.local/share/lldb");
207   return true;
208 }
209 
210 void HostInfoLinux::ComputeHostArchitectureSupport(ArchSpec &arch_32,
211                                                    ArchSpec &arch_64) {
212   HostInfoPosix::ComputeHostArchitectureSupport(arch_32, arch_64);
213 
214   const char *distribution_id = GetDistributionId().data();
215 
216   // On Linux, "unknown" in the vendor slot isn't what we want for the default
217   // triple.  It's probably an artifact of config.guess.
218   if (arch_32.IsValid()) {
219     arch_32.SetDistributionId(distribution_id);
220     if (arch_32.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
221       arch_32.GetTriple().setVendorName(llvm::StringRef());
222   }
223   if (arch_64.IsValid()) {
224     arch_64.SetDistributionId(distribution_id);
225     if (arch_64.GetTriple().getVendor() == llvm::Triple::UnknownVendor)
226       arch_64.GetTriple().setVendorName(llvm::StringRef());
227   }
228 }
229