1 //===-- PlatformLinux.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 "PlatformLinux.h"
10 #include "lldb/Host/Config.h"
11 
12 #include <cstdio>
13 #if LLDB_ENABLE_POSIX
14 #include <sys/utsname.h>
15 #endif
16 
17 #include "lldb/Core/Debugger.h"
18 #include "lldb/Core/PluginManager.h"
19 #include "lldb/Host/HostInfo.h"
20 #include "lldb/Target/Process.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Utility/FileSpec.h"
23 #include "lldb/Utility/Log.h"
24 #include "lldb/Utility/State.h"
25 #include "lldb/Utility/Status.h"
26 #include "lldb/Utility/StreamString.h"
27 
28 // Define these constants from Linux mman.h for use when targeting remote linux
29 // systems even when host has different values.
30 #define MAP_PRIVATE 2
31 #define MAP_ANON 0x20
32 
33 using namespace lldb;
34 using namespace lldb_private;
35 using namespace lldb_private::platform_linux;
36 
37 LLDB_PLUGIN_DEFINE(PlatformLinux)
38 
39 static uint32_t g_initialize_count = 0;
40 
41 
42 PlatformSP PlatformLinux::CreateInstance(bool force, const ArchSpec *arch) {
43   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
44   LLDB_LOG(log, "force = {0}, arch=({1}, {2})", force,
45            arch ? arch->GetArchitectureName() : "<null>",
46            arch ? arch->GetTriple().getTriple() : "<null>");
47 
48   bool create = force;
49   if (!create && arch && arch->IsValid()) {
50     const llvm::Triple &triple = arch->GetTriple();
51     switch (triple.getOS()) {
52     case llvm::Triple::Linux:
53       create = true;
54       break;
55 
56 #if defined(__linux__)
57     // Only accept "unknown" for the OS if the host is linux and it "unknown"
58     // wasn't specified (it was just returned because it was NOT specified)
59     case llvm::Triple::OSType::UnknownOS:
60       create = !arch->TripleOSWasSpecified();
61       break;
62 #endif
63     default:
64       break;
65     }
66   }
67 
68   LLDB_LOG(log, "create = {0}", create);
69   if (create) {
70     return PlatformSP(new PlatformLinux(false));
71   }
72   return PlatformSP();
73 }
74 
75 llvm::StringRef PlatformLinux::GetPluginDescriptionStatic(bool is_host) {
76   if (is_host)
77     return "Local Linux user platform plug-in.";
78   return "Remote Linux user platform plug-in.";
79 }
80 
81 void PlatformLinux::Initialize() {
82   PlatformPOSIX::Initialize();
83 
84   if (g_initialize_count++ == 0) {
85 #if defined(__linux__) && !defined(__ANDROID__)
86     PlatformSP default_platform_sp(new PlatformLinux(true));
87     default_platform_sp->SetSystemArchitecture(HostInfo::GetArchitecture());
88     Platform::SetHostPlatform(default_platform_sp);
89 #endif
90     PluginManager::RegisterPlugin(
91         PlatformLinux::GetPluginNameStatic(false),
92         PlatformLinux::GetPluginDescriptionStatic(false),
93         PlatformLinux::CreateInstance, nullptr);
94   }
95 }
96 
97 void PlatformLinux::Terminate() {
98   if (g_initialize_count > 0) {
99     if (--g_initialize_count == 0) {
100       PluginManager::UnregisterPlugin(PlatformLinux::CreateInstance);
101     }
102   }
103 
104   PlatformPOSIX::Terminate();
105 }
106 
107 /// Default Constructor
108 PlatformLinux::PlatformLinux(bool is_host)
109     : PlatformPOSIX(is_host) // This is the local host platform
110 {}
111 
112 bool PlatformLinux::GetSupportedArchitectureAtIndex(uint32_t idx,
113                                                     ArchSpec &arch) {
114   if (IsHost()) {
115     ArchSpec hostArch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
116     if (hostArch.GetTriple().isOSLinux()) {
117       if (idx == 0) {
118         arch = hostArch;
119         return arch.IsValid();
120       } else if (idx == 1) {
121         // If the default host architecture is 64-bit, look for a 32-bit
122         // variant
123         if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit()) {
124           arch = HostInfo::GetArchitecture(HostInfo::eArchKind32);
125           return arch.IsValid();
126         }
127       }
128     }
129   } else {
130     if (m_remote_platform_sp)
131       return m_remote_platform_sp->GetSupportedArchitectureAtIndex(idx, arch);
132 
133     llvm::Triple triple;
134     // Set the OS to linux
135     triple.setOS(llvm::Triple::Linux);
136     // Set the architecture
137     switch (idx) {
138     case 0:
139       triple.setArchName("x86_64");
140       break;
141     case 1:
142       triple.setArchName("i386");
143       break;
144     case 2:
145       triple.setArchName("arm");
146       break;
147     case 3:
148       triple.setArchName("aarch64");
149       break;
150     case 4:
151       triple.setArchName("mips64");
152       break;
153     case 5:
154       triple.setArchName("hexagon");
155       break;
156     case 6:
157       triple.setArchName("mips");
158       break;
159     case 7:
160       triple.setArchName("mips64el");
161       break;
162     case 8:
163       triple.setArchName("mipsel");
164       break;
165     case 9:
166       triple.setArchName("s390x");
167       break;
168     default:
169       return false;
170     }
171     // Leave the vendor as "llvm::Triple:UnknownVendor" and don't specify the
172     // vendor by calling triple.SetVendorName("unknown") so that it is a
173     // "unspecified unknown". This means when someone calls
174     // triple.GetVendorName() it will return an empty string which indicates
175     // that the vendor can be set when two architectures are merged
176 
177     // Now set the triple into "arch" and return true
178     arch.SetTriple(triple);
179     return true;
180   }
181   return false;
182 }
183 
184 void PlatformLinux::GetStatus(Stream &strm) {
185   Platform::GetStatus(strm);
186 
187 #if LLDB_ENABLE_POSIX
188   // Display local kernel information only when we are running in host mode.
189   // Otherwise, we would end up printing non-Linux information (when running on
190   // Mac OS for example).
191   if (IsHost()) {
192     struct utsname un;
193 
194     if (uname(&un))
195       return;
196 
197     strm.Printf("    Kernel: %s\n", un.sysname);
198     strm.Printf("   Release: %s\n", un.release);
199     strm.Printf("   Version: %s\n", un.version);
200   }
201 #endif
202 }
203 
204 uint32_t
205 PlatformLinux::GetResumeCountForLaunchInfo(ProcessLaunchInfo &launch_info) {
206   uint32_t resume_count = 0;
207 
208   // Always resume past the initial stop when we use eLaunchFlagDebug
209   if (launch_info.GetFlags().Test(eLaunchFlagDebug)) {
210     // Resume past the stop for the final exec into the true inferior.
211     ++resume_count;
212   }
213 
214   // If we're not launching a shell, we're done.
215   const FileSpec &shell = launch_info.GetShell();
216   if (!shell)
217     return resume_count;
218 
219   std::string shell_string = shell.GetPath();
220   // We're in a shell, so for sure we have to resume past the shell exec.
221   ++resume_count;
222 
223   // Figure out what shell we're planning on using.
224   const char *shell_name = strrchr(shell_string.c_str(), '/');
225   if (shell_name == nullptr)
226     shell_name = shell_string.c_str();
227   else
228     shell_name++;
229 
230   if (strcmp(shell_name, "csh") == 0 || strcmp(shell_name, "tcsh") == 0 ||
231       strcmp(shell_name, "zsh") == 0 || strcmp(shell_name, "sh") == 0) {
232     // These shells seem to re-exec themselves.  Add another resume.
233     ++resume_count;
234   }
235 
236   return resume_count;
237 }
238 
239 bool PlatformLinux::CanDebugProcess() {
240   if (IsHost()) {
241     return true;
242   } else {
243     // If we're connected, we can debug.
244     return IsConnected();
245   }
246 }
247 
248 void PlatformLinux::CalculateTrapHandlerSymbolNames() {
249   m_trap_handlers.push_back(ConstString("_sigtramp"));
250   m_trap_handlers.push_back(ConstString("__kernel_rt_sigreturn"));
251   m_trap_handlers.push_back(ConstString("__restore_rt"));
252 }
253 
254 MmapArgList PlatformLinux::GetMmapArgumentList(const ArchSpec &arch,
255                                                addr_t addr, addr_t length,
256                                                unsigned prot, unsigned flags,
257                                                addr_t fd, addr_t offset) {
258   uint64_t flags_platform = 0;
259   uint64_t map_anon = arch.IsMIPS() ? 0x800 : MAP_ANON;
260 
261   if (flags & eMmapFlagsPrivate)
262     flags_platform |= MAP_PRIVATE;
263   if (flags & eMmapFlagsAnon)
264     flags_platform |= map_anon;
265 
266   MmapArgList args({addr, length, prot, flags_platform, fd, offset});
267   return args;
268 }
269 
270