1 //===-- PlatformLinux.cpp ---------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "PlatformLinux.h"
11 #include "lldb/Host/Config.h"
12 
13 #include <stdio.h>
14 #ifndef LLDB_DISABLE_POSIX
15 #include <sys/utsname.h>
16 #endif
17 
18 #include "lldb/Core/Debugger.h"
19 #include "lldb/Core/PluginManager.h"
20 #include "lldb/Host/HostInfo.h"
21 #include "lldb/Target/Process.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Utility/FileSpec.h"
24 #include "lldb/Utility/Log.h"
25 #include "lldb/Utility/State.h"
26 #include "lldb/Utility/Status.h"
27 #include "lldb/Utility/StreamString.h"
28 
29 // Define these constants from Linux mman.h for use when targeting remote linux
30 // systems even when host has different values.
31 #define MAP_PRIVATE 2
32 #define MAP_ANON 0x20
33 
34 using namespace lldb;
35 using namespace lldb_private;
36 using namespace lldb_private::platform_linux;
37 
38 static uint32_t g_initialize_count = 0;
39 
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 ConstString PlatformLinux::GetPluginNameStatic(bool is_host) {
76   if (is_host) {
77     static ConstString g_host_name(Platform::GetHostPlatformName());
78     return g_host_name;
79   } else {
80     static ConstString g_remote_name("remote-linux");
81     return g_remote_name;
82   }
83 }
84 
85 const char *PlatformLinux::GetPluginDescriptionStatic(bool is_host) {
86   if (is_host)
87     return "Local Linux user platform plug-in.";
88   else
89     return "Remote Linux user platform plug-in.";
90 }
91 
92 ConstString PlatformLinux::GetPluginName() {
93   return GetPluginNameStatic(IsHost());
94 }
95 
96 void PlatformLinux::Initialize() {
97   PlatformPOSIX::Initialize();
98 
99   if (g_initialize_count++ == 0) {
100 #if defined(__linux__) && !defined(__ANDROID__)
101     PlatformSP default_platform_sp(new PlatformLinux(true));
102     default_platform_sp->SetSystemArchitecture(HostInfo::GetArchitecture());
103     Platform::SetHostPlatform(default_platform_sp);
104 #endif
105     PluginManager::RegisterPlugin(
106         PlatformLinux::GetPluginNameStatic(false),
107         PlatformLinux::GetPluginDescriptionStatic(false),
108         PlatformLinux::CreateInstance, nullptr);
109   }
110 }
111 
112 void PlatformLinux::Terminate() {
113   if (g_initialize_count > 0) {
114     if (--g_initialize_count == 0) {
115       PluginManager::UnregisterPlugin(PlatformLinux::CreateInstance);
116     }
117   }
118 
119   PlatformPOSIX::Terminate();
120 }
121 
122 //------------------------------------------------------------------
123 /// Default Constructor
124 //------------------------------------------------------------------
125 PlatformLinux::PlatformLinux(bool is_host)
126     : PlatformPOSIX(is_host) // This is the local host platform
127 {}
128 
129 PlatformLinux::~PlatformLinux() = default;
130 
131 bool PlatformLinux::GetSupportedArchitectureAtIndex(uint32_t idx,
132                                                     ArchSpec &arch) {
133   if (IsHost()) {
134     ArchSpec hostArch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
135     if (hostArch.GetTriple().isOSLinux()) {
136       if (idx == 0) {
137         arch = hostArch;
138         return arch.IsValid();
139       } else if (idx == 1) {
140         // If the default host architecture is 64-bit, look for a 32-bit
141         // variant
142         if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit()) {
143           arch = HostInfo::GetArchitecture(HostInfo::eArchKind32);
144           return arch.IsValid();
145         }
146       }
147     }
148   } else {
149     if (m_remote_platform_sp)
150       return m_remote_platform_sp->GetSupportedArchitectureAtIndex(idx, arch);
151 
152     llvm::Triple triple;
153     // Set the OS to linux
154     triple.setOS(llvm::Triple::Linux);
155     // Set the architecture
156     switch (idx) {
157     case 0:
158       triple.setArchName("x86_64");
159       break;
160     case 1:
161       triple.setArchName("i386");
162       break;
163     case 2:
164       triple.setArchName("arm");
165       break;
166     case 3:
167       triple.setArchName("aarch64");
168       break;
169     case 4:
170       triple.setArchName("mips64");
171       break;
172     case 5:
173       triple.setArchName("hexagon");
174       break;
175     case 6:
176       triple.setArchName("mips");
177       break;
178     case 7:
179       triple.setArchName("mips64el");
180       break;
181     case 8:
182       triple.setArchName("mipsel");
183       break;
184     case 9:
185       triple.setArchName("s390x");
186       break;
187     default:
188       return false;
189     }
190     // Leave the vendor as "llvm::Triple:UnknownVendor" and don't specify the
191     // vendor by calling triple.SetVendorName("unknown") so that it is a
192     // "unspecified unknown". This means when someone calls
193     // triple.GetVendorName() it will return an empty string which indicates
194     // that the vendor can be set when two architectures are merged
195 
196     // Now set the triple into "arch" and return true
197     arch.SetTriple(triple);
198     return true;
199   }
200   return false;
201 }
202 
203 void PlatformLinux::GetStatus(Stream &strm) {
204   Platform::GetStatus(strm);
205 
206 #ifndef LLDB_DISABLE_POSIX
207   // Display local kernel information only when we are running in host mode.
208   // Otherwise, we would end up printing non-Linux information (when running on
209   // Mac OS for example).
210   if (IsHost()) {
211     struct utsname un;
212 
213     if (uname(&un))
214       return;
215 
216     strm.Printf("    Kernel: %s\n", un.sysname);
217     strm.Printf("   Release: %s\n", un.release);
218     strm.Printf("   Version: %s\n", un.version);
219   }
220 #endif
221 }
222 
223 int32_t
224 PlatformLinux::GetResumeCountForLaunchInfo(ProcessLaunchInfo &launch_info) {
225   int32_t resume_count = 0;
226 
227   // Always resume past the initial stop when we use eLaunchFlagDebug
228   if (launch_info.GetFlags().Test(eLaunchFlagDebug)) {
229     // Resume past the stop for the final exec into the true inferior.
230     ++resume_count;
231   }
232 
233   // If we're not launching a shell, we're done.
234   const FileSpec &shell = launch_info.GetShell();
235   if (!shell)
236     return resume_count;
237 
238   std::string shell_string = shell.GetPath();
239   // We're in a shell, so for sure we have to resume past the shell exec.
240   ++resume_count;
241 
242   // Figure out what shell we're planning on using.
243   const char *shell_name = strrchr(shell_string.c_str(), '/');
244   if (shell_name == NULL)
245     shell_name = shell_string.c_str();
246   else
247     shell_name++;
248 
249   if (strcmp(shell_name, "csh") == 0 || strcmp(shell_name, "tcsh") == 0 ||
250       strcmp(shell_name, "zsh") == 0 || strcmp(shell_name, "sh") == 0) {
251     // These shells seem to re-exec themselves.  Add another resume.
252     ++resume_count;
253   }
254 
255   return resume_count;
256 }
257 
258 bool PlatformLinux::CanDebugProcess() {
259   if (IsHost()) {
260     return true;
261   } else {
262     // If we're connected, we can debug.
263     return IsConnected();
264   }
265 }
266 
267 // For local debugging, Linux will override the debug logic to use llgs-launch
268 // rather than lldb-launch, llgs-attach.  This differs from current lldb-
269 // launch, debugserver-attach approach on MacOSX.
270 lldb::ProcessSP
271 PlatformLinux::DebugProcess(ProcessLaunchInfo &launch_info, Debugger &debugger,
272                             Target *target, // Can be NULL, if NULL create a new
273                                             // target, else use existing one
274                             Status &error) {
275   Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PLATFORM));
276   LLDB_LOG(log, "target {0}", target);
277 
278   // If we're a remote host, use standard behavior from parent class.
279   if (!IsHost())
280     return PlatformPOSIX::DebugProcess(launch_info, debugger, target, error);
281 
282   //
283   // For local debugging, we'll insist on having ProcessGDBRemote create the
284   // process.
285   //
286 
287   ProcessSP process_sp;
288 
289   // Make sure we stop at the entry point
290   launch_info.GetFlags().Set(eLaunchFlagDebug);
291 
292   // We always launch the process we are going to debug in a separate process
293   // group, since then we can handle ^C interrupts ourselves w/o having to
294   // worry about the target getting them as well.
295   launch_info.SetLaunchInSeparateProcessGroup(true);
296 
297   // Ensure we have a target.
298   if (target == nullptr) {
299     LLDB_LOG(log, "creating new target");
300     TargetSP new_target_sp;
301     error = debugger.GetTargetList().CreateTarget(
302         debugger, "", "", eLoadDependentsNo, nullptr, new_target_sp);
303     if (error.Fail()) {
304       LLDB_LOG(log, "failed to create new target: {0}", error);
305       return process_sp;
306     }
307 
308     target = new_target_sp.get();
309     if (!target) {
310       error.SetErrorString("CreateTarget() returned nullptr");
311       LLDB_LOG(log, "error: {0}", error);
312       return process_sp;
313     }
314   }
315 
316   // Mark target as currently selected target.
317   debugger.GetTargetList().SetSelectedTarget(target);
318 
319   // Now create the gdb-remote process.
320   LLDB_LOG(log, "having target create process with gdb-remote plugin");
321   process_sp = target->CreateProcess(
322       launch_info.GetListenerForProcess(debugger), "gdb-remote", nullptr);
323 
324   if (!process_sp) {
325     error.SetErrorString("CreateProcess() failed for gdb-remote process");
326     LLDB_LOG(log, "error: {0}", error);
327     return process_sp;
328   }
329 
330   LLDB_LOG(log, "successfully created process");
331   // Adjust launch for a hijacker.
332   ListenerSP listener_sp;
333   if (!launch_info.GetHijackListener()) {
334     LLDB_LOG(log, "setting up hijacker");
335     listener_sp =
336         Listener::MakeListener("lldb.PlatformLinux.DebugProcess.hijack");
337     launch_info.SetHijackListener(listener_sp);
338     process_sp->HijackProcessEvents(listener_sp);
339   }
340 
341   // Log file actions.
342   if (log) {
343     LLDB_LOG(log, "launching process with the following file actions:");
344     StreamString stream;
345     size_t i = 0;
346     const FileAction *file_action;
347     while ((file_action = launch_info.GetFileActionAtIndex(i++)) != nullptr) {
348       file_action->Dump(stream);
349       LLDB_LOG(log, "{0}", stream.GetData());
350       stream.Clear();
351     }
352   }
353 
354   // Do the launch.
355   error = process_sp->Launch(launch_info);
356   if (error.Success()) {
357     // Handle the hijacking of process events.
358     if (listener_sp) {
359       const StateType state = process_sp->WaitForProcessToStop(
360           llvm::None, NULL, false, listener_sp);
361 
362       LLDB_LOG(log, "pid {0} state {0}", process_sp->GetID(), state);
363     }
364 
365     // Hook up process PTY if we have one (which we should for local debugging
366     // with llgs).
367     int pty_fd = launch_info.GetPTY().ReleaseMasterFileDescriptor();
368     if (pty_fd != PseudoTerminal::invalid_fd) {
369       process_sp->SetSTDIOFileDescriptor(pty_fd);
370       LLDB_LOG(log, "hooked up STDIO pty to process");
371     } else
372       LLDB_LOG(log, "not using process STDIO pty");
373   } else {
374     LLDB_LOG(log, "process launch failed: {0}", error);
375     // FIXME figure out appropriate cleanup here.  Do we delete the target? Do
376     // we delete the process?  Does our caller do that?
377   }
378 
379   return process_sp;
380 }
381 
382 void PlatformLinux::CalculateTrapHandlerSymbolNames() {
383   m_trap_handlers.push_back(ConstString("_sigtramp"));
384 }
385 
386 MmapArgList PlatformLinux::GetMmapArgumentList(const ArchSpec &arch,
387                                                addr_t addr, addr_t length,
388                                                unsigned prot, unsigned flags,
389                                                addr_t fd, addr_t offset) {
390   uint64_t flags_platform = 0;
391   uint64_t map_anon = MAP_ANON;
392 
393   // To get correct flags for MIPS Architecture
394   if (arch.GetTriple().getArch() == llvm::Triple::mips64 ||
395       arch.GetTriple().getArch() == llvm::Triple::mips64el ||
396       arch.GetTriple().getArch() == llvm::Triple::mips ||
397       arch.GetTriple().getArch() == llvm::Triple::mipsel)
398     map_anon = 0x800;
399 
400   if (flags & eMmapFlagsPrivate)
401     flags_platform |= MAP_PRIVATE;
402   if (flags & eMmapFlagsAnon)
403     flags_platform |= map_anon;
404 
405   MmapArgList args({addr, length, prot, flags_platform, fd, offset});
406   return args;
407 }
408 
409