1 //===-- PlatformLinux.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 "PlatformLinux.h"
10 #include "lldb/Host/Config.h"
11 
12 #include <stdio.h>
13 #ifndef LLDB_DISABLE_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 static uint32_t g_initialize_count = 0;
38 
39 
40 PlatformSP PlatformLinux::CreateInstance(bool force, const ArchSpec *arch) {
41   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
42   LLDB_LOG(log, "force = {0}, arch=({1}, {2})", force,
43            arch ? arch->GetArchitectureName() : "<null>",
44            arch ? arch->GetTriple().getTriple() : "<null>");
45 
46   bool create = force;
47   if (!create && arch && arch->IsValid()) {
48     const llvm::Triple &triple = arch->GetTriple();
49     switch (triple.getOS()) {
50     case llvm::Triple::Linux:
51       create = true;
52       break;
53 
54 #if defined(__linux__)
55     // Only accept "unknown" for the OS if the host is linux and it "unknown"
56     // wasn't specified (it was just returned because it was NOT specified)
57     case llvm::Triple::OSType::UnknownOS:
58       create = !arch->TripleOSWasSpecified();
59       break;
60 #endif
61     default:
62       break;
63     }
64   }
65 
66   LLDB_LOG(log, "create = {0}", create);
67   if (create) {
68     return PlatformSP(new PlatformLinux(false));
69   }
70   return PlatformSP();
71 }
72 
73 ConstString PlatformLinux::GetPluginNameStatic(bool is_host) {
74   if (is_host) {
75     static ConstString g_host_name(Platform::GetHostPlatformName());
76     return g_host_name;
77   } else {
78     static ConstString g_remote_name("remote-linux");
79     return g_remote_name;
80   }
81 }
82 
83 const char *PlatformLinux::GetPluginDescriptionStatic(bool is_host) {
84   if (is_host)
85     return "Local Linux user platform plug-in.";
86   else
87     return "Remote Linux user platform plug-in.";
88 }
89 
90 ConstString PlatformLinux::GetPluginName() {
91   return GetPluginNameStatic(IsHost());
92 }
93 
94 void PlatformLinux::Initialize() {
95   PlatformPOSIX::Initialize();
96 
97   if (g_initialize_count++ == 0) {
98 #if defined(__linux__) && !defined(__ANDROID__)
99     PlatformSP default_platform_sp(new PlatformLinux(true));
100     default_platform_sp->SetSystemArchitecture(HostInfo::GetArchitecture());
101     Platform::SetHostPlatform(default_platform_sp);
102 #endif
103     PluginManager::RegisterPlugin(
104         PlatformLinux::GetPluginNameStatic(false),
105         PlatformLinux::GetPluginDescriptionStatic(false),
106         PlatformLinux::CreateInstance, nullptr);
107   }
108 }
109 
110 void PlatformLinux::Terminate() {
111   if (g_initialize_count > 0) {
112     if (--g_initialize_count == 0) {
113       PluginManager::UnregisterPlugin(PlatformLinux::CreateInstance);
114     }
115   }
116 
117   PlatformPOSIX::Terminate();
118 }
119 
120 /// Default Constructor
121 PlatformLinux::PlatformLinux(bool is_host)
122     : PlatformPOSIX(is_host) // This is the local host platform
123 {}
124 
125 PlatformLinux::~PlatformLinux() = default;
126 
127 bool PlatformLinux::GetSupportedArchitectureAtIndex(uint32_t idx,
128                                                     ArchSpec &arch) {
129   if (IsHost()) {
130     ArchSpec hostArch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
131     if (hostArch.GetTriple().isOSLinux()) {
132       if (idx == 0) {
133         arch = hostArch;
134         return arch.IsValid();
135       } else if (idx == 1) {
136         // If the default host architecture is 64-bit, look for a 32-bit
137         // variant
138         if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit()) {
139           arch = HostInfo::GetArchitecture(HostInfo::eArchKind32);
140           return arch.IsValid();
141         }
142       }
143     }
144   } else {
145     if (m_remote_platform_sp)
146       return m_remote_platform_sp->GetSupportedArchitectureAtIndex(idx, arch);
147 
148     llvm::Triple triple;
149     // Set the OS to linux
150     triple.setOS(llvm::Triple::Linux);
151     // Set the architecture
152     switch (idx) {
153     case 0:
154       triple.setArchName("x86_64");
155       break;
156     case 1:
157       triple.setArchName("i386");
158       break;
159     case 2:
160       triple.setArchName("arm");
161       break;
162     case 3:
163       triple.setArchName("aarch64");
164       break;
165     case 4:
166       triple.setArchName("mips64");
167       break;
168     case 5:
169       triple.setArchName("hexagon");
170       break;
171     case 6:
172       triple.setArchName("mips");
173       break;
174     case 7:
175       triple.setArchName("mips64el");
176       break;
177     case 8:
178       triple.setArchName("mipsel");
179       break;
180     case 9:
181       triple.setArchName("s390x");
182       break;
183     default:
184       return false;
185     }
186     // Leave the vendor as "llvm::Triple:UnknownVendor" and don't specify the
187     // vendor by calling triple.SetVendorName("unknown") so that it is a
188     // "unspecified unknown". This means when someone calls
189     // triple.GetVendorName() it will return an empty string which indicates
190     // that the vendor can be set when two architectures are merged
191 
192     // Now set the triple into "arch" and return true
193     arch.SetTriple(triple);
194     return true;
195   }
196   return false;
197 }
198 
199 void PlatformLinux::GetStatus(Stream &strm) {
200   Platform::GetStatus(strm);
201 
202 #ifndef LLDB_DISABLE_POSIX
203   // Display local kernel information only when we are running in host mode.
204   // Otherwise, we would end up printing non-Linux information (when running on
205   // Mac OS for example).
206   if (IsHost()) {
207     struct utsname un;
208 
209     if (uname(&un))
210       return;
211 
212     strm.Printf("    Kernel: %s\n", un.sysname);
213     strm.Printf("   Release: %s\n", un.release);
214     strm.Printf("   Version: %s\n", un.version);
215   }
216 #endif
217 }
218 
219 int32_t
220 PlatformLinux::GetResumeCountForLaunchInfo(ProcessLaunchInfo &launch_info) {
221   int32_t resume_count = 0;
222 
223   // Always resume past the initial stop when we use eLaunchFlagDebug
224   if (launch_info.GetFlags().Test(eLaunchFlagDebug)) {
225     // Resume past the stop for the final exec into the true inferior.
226     ++resume_count;
227   }
228 
229   // If we're not launching a shell, we're done.
230   const FileSpec &shell = launch_info.GetShell();
231   if (!shell)
232     return resume_count;
233 
234   std::string shell_string = shell.GetPath();
235   // We're in a shell, so for sure we have to resume past the shell exec.
236   ++resume_count;
237 
238   // Figure out what shell we're planning on using.
239   const char *shell_name = strrchr(shell_string.c_str(), '/');
240   if (shell_name == NULL)
241     shell_name = shell_string.c_str();
242   else
243     shell_name++;
244 
245   if (strcmp(shell_name, "csh") == 0 || strcmp(shell_name, "tcsh") == 0 ||
246       strcmp(shell_name, "zsh") == 0 || strcmp(shell_name, "sh") == 0) {
247     // These shells seem to re-exec themselves.  Add another resume.
248     ++resume_count;
249   }
250 
251   return resume_count;
252 }
253 
254 bool PlatformLinux::CanDebugProcess() {
255   if (IsHost()) {
256     return true;
257   } else {
258     // If we're connected, we can debug.
259     return IsConnected();
260   }
261 }
262 
263 std::vector<std::string>
264 PlatformLinux::GetSystemIncludeDirectories(lldb::LanguageType lang) {
265   std::string sys_root = GetSDKRootDirectory().AsCString("");
266   switch (lang) {
267   case lldb::eLanguageTypeC:
268   case lldb::eLanguageTypeC89:
269   case lldb::eLanguageTypeC99:
270   case lldb::eLanguageTypeC11:
271   case lldb::eLanguageTypeC_plus_plus:
272   case lldb::eLanguageTypeC_plus_plus_03:
273   case lldb::eLanguageTypeC_plus_plus_11:
274   case lldb::eLanguageTypeC_plus_plus_14:
275   case lldb::eLanguageTypeObjC_plus_plus:
276     return {sys_root + "/usr/include/"};
277   default:
278     return {};
279   }
280 }
281 
282 // For local debugging, Linux will override the debug logic to use llgs-launch
283 // rather than lldb-launch, llgs-attach.  This differs from current lldb-
284 // launch, debugserver-attach approach on MacOSX.
285 lldb::ProcessSP
286 PlatformLinux::DebugProcess(ProcessLaunchInfo &launch_info, Debugger &debugger,
287                             Target *target, // Can be NULL, if NULL create a new
288                                             // target, else use existing one
289                             Status &error) {
290   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
291   LLDB_LOG(log, "target {0}", target);
292 
293   // If we're a remote host, use standard behavior from parent class.
294   if (!IsHost())
295     return PlatformPOSIX::DebugProcess(launch_info, debugger, target, error);
296 
297   //
298   // For local debugging, we'll insist on having ProcessGDBRemote create the
299   // process.
300   //
301 
302   ProcessSP process_sp;
303 
304   // Make sure we stop at the entry point
305   launch_info.GetFlags().Set(eLaunchFlagDebug);
306 
307   // We always launch the process we are going to debug in a separate process
308   // group, since then we can handle ^C interrupts ourselves w/o having to
309   // worry about the target getting them as well.
310   launch_info.SetLaunchInSeparateProcessGroup(true);
311 
312   // Ensure we have a target.
313   if (target == nullptr) {
314     LLDB_LOG(log, "creating new target");
315     TargetSP new_target_sp;
316     error = debugger.GetTargetList().CreateTarget(
317         debugger, "", "", eLoadDependentsNo, nullptr, new_target_sp);
318     if (error.Fail()) {
319       LLDB_LOG(log, "failed to create new target: {0}", error);
320       return process_sp;
321     }
322 
323     target = new_target_sp.get();
324     if (!target) {
325       error.SetErrorString("CreateTarget() returned nullptr");
326       LLDB_LOG(log, "error: {0}", error);
327       return process_sp;
328     }
329   }
330 
331   // Mark target as currently selected target.
332   debugger.GetTargetList().SetSelectedTarget(target);
333 
334   // Now create the gdb-remote process.
335   LLDB_LOG(log, "having target create process with gdb-remote plugin");
336   process_sp =
337       target->CreateProcess(launch_info.GetListener(), "gdb-remote", nullptr);
338 
339   if (!process_sp) {
340     error.SetErrorString("CreateProcess() failed for gdb-remote process");
341     LLDB_LOG(log, "error: {0}", error);
342     return process_sp;
343   }
344 
345   LLDB_LOG(log, "successfully created process");
346   // Adjust launch for a hijacker.
347   ListenerSP listener_sp;
348   if (!launch_info.GetHijackListener()) {
349     LLDB_LOG(log, "setting up hijacker");
350     listener_sp =
351         Listener::MakeListener("lldb.PlatformLinux.DebugProcess.hijack");
352     launch_info.SetHijackListener(listener_sp);
353     process_sp->HijackProcessEvents(listener_sp);
354   }
355 
356   // Log file actions.
357   if (log) {
358     LLDB_LOG(log, "launching process with the following file actions:");
359     StreamString stream;
360     size_t i = 0;
361     const FileAction *file_action;
362     while ((file_action = launch_info.GetFileActionAtIndex(i++)) != nullptr) {
363       file_action->Dump(stream);
364       LLDB_LOG(log, "{0}", stream.GetData());
365       stream.Clear();
366     }
367   }
368 
369   // Do the launch.
370   error = process_sp->Launch(launch_info);
371   if (error.Success()) {
372     // Handle the hijacking of process events.
373     if (listener_sp) {
374       const StateType state = process_sp->WaitForProcessToStop(
375           llvm::None, NULL, false, listener_sp);
376 
377       LLDB_LOG(log, "pid {0} state {0}", process_sp->GetID(), state);
378     }
379 
380     // Hook up process PTY if we have one (which we should for local debugging
381     // with llgs).
382     int pty_fd = launch_info.GetPTY().ReleaseMasterFileDescriptor();
383     if (pty_fd != PseudoTerminal::invalid_fd) {
384       process_sp->SetSTDIOFileDescriptor(pty_fd);
385       LLDB_LOG(log, "hooked up STDIO pty to process");
386     } else
387       LLDB_LOG(log, "not using process STDIO pty");
388   } else {
389     LLDB_LOG(log, "process launch failed: {0}", error);
390     // FIXME figure out appropriate cleanup here.  Do we delete the target? Do
391     // we delete the process?  Does our caller do that?
392   }
393 
394   return process_sp;
395 }
396 
397 void PlatformLinux::CalculateTrapHandlerSymbolNames() {
398   m_trap_handlers.push_back(ConstString("_sigtramp"));
399 }
400 
401 MmapArgList PlatformLinux::GetMmapArgumentList(const ArchSpec &arch,
402                                                addr_t addr, addr_t length,
403                                                unsigned prot, unsigned flags,
404                                                addr_t fd, addr_t offset) {
405   uint64_t flags_platform = 0;
406   uint64_t map_anon = arch.IsMIPS() ? 0x800 : MAP_ANON;
407 
408   if (flags & eMmapFlagsPrivate)
409     flags_platform |= MAP_PRIVATE;
410   if (flags & eMmapFlagsAnon)
411     flags_platform |= map_anon;
412 
413   MmapArgList args({addr, length, prot, flags_platform, fd, offset});
414   return args;
415 }
416 
417