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