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 "lldb/lldb-python.h"
11 
12 #include "PlatformLinux.h"
13 #include "lldb/Host/Config.h"
14 
15 // C Includes
16 #include <stdio.h>
17 #ifndef LLDB_DISABLE_POSIX
18 #include <sys/utsname.h>
19 #endif
20 
21 // C++ Includes
22 // Other libraries and framework includes
23 // Project includes
24 #include "lldb/Breakpoint/BreakpointLocation.h"
25 #include "lldb/Core/Debugger.h"
26 #include "lldb/Core/Error.h"
27 #include "lldb/Core/Log.h"
28 #include "lldb/Core/Module.h"
29 #include "lldb/Core/ModuleList.h"
30 #include "lldb/Core/ModuleSpec.h"
31 #include "lldb/Core/PluginManager.h"
32 #include "lldb/Core/State.h"
33 #include "lldb/Core/StreamString.h"
34 #include "lldb/Host/FileSpec.h"
35 #include "lldb/Host/HostInfo.h"
36 #include "lldb/Interpreter/OptionValueProperties.h"
37 #include "lldb/Interpreter/Property.h"
38 #include "lldb/Target/Target.h"
39 #include "lldb/Target/Process.h"
40 
41 #if defined(__linux__)
42 #include "../../Process/Linux/NativeProcessLinux.h"
43 #endif
44 
45 using namespace lldb;
46 using namespace lldb_private;
47 using namespace lldb_private::platform_linux;
48 
49 static uint32_t g_initialize_count = 0;
50 
51 //------------------------------------------------------------------
52 /// Code to handle the PlatformLinux settings
53 //------------------------------------------------------------------
54 
55 namespace
56 {
57     enum
58     {
59         ePropertyUseLlgsForLocal = 0,
60     };
61 
62     class PlatformLinuxProperties : public Properties
63     {
64     public:
65         static ConstString&
66         GetSettingName ();
67 
68         PlatformLinuxProperties();
69 
70         virtual
71         ~PlatformLinuxProperties() = default;
72 
73         bool
74         GetUseLlgsForLocal() const;
75 
76     private:
77         static const PropertyDefinition*
78         GetStaticPropertyDefinitions();
79     };
80 
81     typedef std::shared_ptr<PlatformLinuxProperties> PlatformLinuxPropertiesSP;
82 
83 } // anonymous namespace
84 
85 PlatformLinuxProperties::PlatformLinuxProperties() :
86     Properties ()
87 {
88     m_collection_sp.reset (new OptionValueProperties(GetSettingName ()));
89     m_collection_sp->Initialize (GetStaticPropertyDefinitions ());
90 }
91 
92 ConstString&
93 PlatformLinuxProperties::GetSettingName ()
94 {
95     static ConstString g_setting_name("linux");
96     return g_setting_name;
97 }
98 
99 bool
100 PlatformLinuxProperties::GetUseLlgsForLocal() const
101 {
102     const uint32_t idx = ePropertyUseLlgsForLocal;
103     return m_collection_sp->GetPropertyAtIndexAsBoolean (NULL, idx, GetStaticPropertyDefinitions()[idx].default_uint_value != 0);
104 }
105 
106 const PropertyDefinition*
107 PlatformLinuxProperties::GetStaticPropertyDefinitions()
108 {
109     static PropertyDefinition
110     g_properties[] =
111     {
112         { "use-llgs-for-local" , OptionValue::eTypeBoolean, true, true, NULL, NULL, "Control whether the platform uses llgs for local debug sessions." },
113         {  NULL        , OptionValue::eTypeInvalid, false, 0  , NULL, NULL, NULL  }
114     };
115 
116     // Allow environment variable to disable llgs-local.
117     if (getenv("PLATFORM_LINUX_DISABLE_LLGS_LOCAL"))
118         g_properties[ePropertyUseLlgsForLocal].default_uint_value = false;
119 
120     return g_properties;
121 }
122 
123 static const PlatformLinuxPropertiesSP &
124 GetGlobalProperties()
125 {
126     static PlatformLinuxPropertiesSP g_settings_sp;
127     if (!g_settings_sp)
128         g_settings_sp.reset (new PlatformLinuxProperties ());
129     return g_settings_sp;
130 }
131 
132 void
133 PlatformLinux::DebuggerInitialize (Debugger &debugger)
134 {
135     if (!PluginManager::GetSettingForPlatformPlugin (debugger, PlatformLinuxProperties::GetSettingName()))
136     {
137         const bool is_global_setting = true;
138         PluginManager::CreateSettingForPlatformPlugin (debugger,
139                                                        GetGlobalProperties()->GetValueProperties(),
140                                                        ConstString ("Properties for the PlatformLinux plug-in."),
141                                                        is_global_setting);
142     }
143 }
144 
145 
146 //------------------------------------------------------------------
147 
148 PlatformSP
149 PlatformLinux::CreateInstance (bool force, const ArchSpec *arch)
150 {
151     Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_PLATFORM));
152     if (log)
153     {
154         const char *arch_name;
155         if (arch && arch->GetArchitectureName ())
156             arch_name = arch->GetArchitectureName ();
157         else
158             arch_name = "<null>";
159 
160         const char *triple_cstr = arch ? arch->GetTriple ().getTriple ().c_str() : "<null>";
161 
162         log->Printf ("PlatformLinux::%s(force=%s, arch={%s,%s})", __FUNCTION__, force ? "true" : "false", arch_name, triple_cstr);
163     }
164 
165     bool create = force;
166     if (create == false && arch && arch->IsValid())
167     {
168         const llvm::Triple &triple = arch->GetTriple();
169         switch (triple.getVendor())
170         {
171             case llvm::Triple::PC:
172                 create = true;
173                 break;
174 
175 #if defined(__linux__)
176             // Only accept "unknown" for the vendor if the host is linux and
177             // it "unknown" wasn't specified (it was just returned because it
178             // was NOT specified_
179             case llvm::Triple::VendorType::UnknownVendor:
180                 create = !arch->TripleVendorWasSpecified();
181                 break;
182 #endif
183             default:
184                 break;
185         }
186 
187         if (create)
188         {
189             switch (triple.getOS())
190             {
191                 case llvm::Triple::Linux:
192                     break;
193 
194 #if defined(__linux__)
195                 // Only accept "unknown" for the OS if the host is linux and
196                 // it "unknown" wasn't specified (it was just returned because it
197                 // was NOT specified)
198                 case llvm::Triple::OSType::UnknownOS:
199                     create = !arch->TripleOSWasSpecified();
200                     break;
201 #endif
202                 default:
203                     create = false;
204                     break;
205             }
206         }
207     }
208 
209     if (create)
210     {
211         if (log)
212             log->Printf ("PlatformLinux::%s() creating remote-linux platform", __FUNCTION__);
213         return PlatformSP(new PlatformLinux(false));
214     }
215 
216     if (log)
217         log->Printf ("PlatformLinux::%s() aborting creation of remote-linux platform", __FUNCTION__);
218 
219     return PlatformSP();
220 }
221 
222 
223 ConstString
224 PlatformLinux::GetPluginNameStatic (bool is_host)
225 {
226     if (is_host)
227     {
228         static ConstString g_host_name(Platform::GetHostPlatformName ());
229         return g_host_name;
230     }
231     else
232     {
233         static ConstString g_remote_name("remote-linux");
234         return g_remote_name;
235     }
236 }
237 
238 const char *
239 PlatformLinux::GetPluginDescriptionStatic (bool is_host)
240 {
241     if (is_host)
242         return "Local Linux user platform plug-in.";
243     else
244         return "Remote Linux user platform plug-in.";
245 }
246 
247 ConstString
248 PlatformLinux::GetPluginName()
249 {
250     return GetPluginNameStatic(IsHost());
251 }
252 
253 void
254 PlatformLinux::Initialize ()
255 {
256     PlatformPOSIX::Initialize ();
257 
258     if (g_initialize_count++ == 0)
259     {
260 #if defined(__linux__) && !defined(__ANDROID__)
261         PlatformSP default_platform_sp (new PlatformLinux(true));
262         default_platform_sp->SetSystemArchitecture(HostInfo::GetArchitecture());
263         Platform::SetHostPlatform (default_platform_sp);
264 #endif
265         PluginManager::RegisterPlugin(PlatformLinux::GetPluginNameStatic(false),
266                                       PlatformLinux::GetPluginDescriptionStatic(false),
267                                       PlatformLinux::CreateInstance,
268                                       PlatformLinux::DebuggerInitialize);
269     }
270 }
271 
272 void
273 PlatformLinux::Terminate ()
274 {
275     if (g_initialize_count > 0)
276     {
277         if (--g_initialize_count == 0)
278         {
279             PluginManager::UnregisterPlugin (PlatformLinux::CreateInstance);
280         }
281     }
282 
283     PlatformPOSIX::Terminate ();
284 }
285 
286 Error
287 PlatformLinux::ResolveExecutable (const ModuleSpec &ms,
288                                   lldb::ModuleSP &exe_module_sp,
289                                   const FileSpecList *module_search_paths_ptr)
290 {
291     Error error;
292     // Nothing special to do here, just use the actual file and architecture
293 
294     char exe_path[PATH_MAX];
295     ModuleSpec resolved_module_spec (ms);
296 
297     if (IsHost())
298     {
299         // If we have "ls" as the exe_file, resolve the executable location based on
300         // the current path variables
301         if (!resolved_module_spec.GetFileSpec().Exists())
302         {
303             resolved_module_spec.GetFileSpec().GetPath(exe_path, sizeof(exe_path));
304             resolved_module_spec.GetFileSpec().SetFile(exe_path, true);
305         }
306 
307         if (!resolved_module_spec.GetFileSpec().Exists())
308             resolved_module_spec.GetFileSpec().ResolveExecutableLocation ();
309 
310         if (resolved_module_spec.GetFileSpec().Exists())
311             error.Clear();
312         else
313         {
314             error.SetErrorStringWithFormat("unable to find executable for '%s'", resolved_module_spec.GetFileSpec().GetPath().c_str());
315         }
316     }
317     else
318     {
319         if (m_remote_platform_sp)
320         {
321             error = GetCachedExecutable (resolved_module_spec, exe_module_sp, nullptr, *m_remote_platform_sp);
322         }
323         else
324         {
325             // We may connect to a process and use the provided executable (Don't use local $PATH).
326 
327             if (resolved_module_spec.GetFileSpec().Exists())
328                 error.Clear();
329             else
330                 error.SetErrorStringWithFormat("the platform is not currently connected, and '%s' doesn't exist in the system root.", exe_path);
331         }
332     }
333 
334     if (error.Success())
335     {
336         if (resolved_module_spec.GetArchitecture().IsValid())
337         {
338             error = ModuleList::GetSharedModule (resolved_module_spec,
339                                                  exe_module_sp,
340                                                  NULL,
341                                                  NULL,
342                                                  NULL);
343             if (error.Fail())
344             {
345                 // If we failed, it may be because the vendor and os aren't known. If that is the
346                 // case, try setting them to the host architecture and give it another try.
347                 llvm::Triple &module_triple = resolved_module_spec.GetArchitecture().GetTriple();
348                 bool is_vendor_specified = (module_triple.getVendor() != llvm::Triple::UnknownVendor);
349                 bool is_os_specified = (module_triple.getOS() != llvm::Triple::UnknownOS);
350                 if (!is_vendor_specified || !is_os_specified)
351                 {
352                     const llvm::Triple &host_triple = HostInfo::GetArchitecture(HostInfo::eArchKindDefault).GetTriple();
353 
354                     if (!is_vendor_specified)
355                         module_triple.setVendorName (host_triple.getVendorName());
356                     if (!is_os_specified)
357                         module_triple.setOSName (host_triple.getOSName());
358 
359                     error = ModuleList::GetSharedModule (resolved_module_spec,
360                                                          exe_module_sp,
361                                                          NULL,
362                                                          NULL,
363                                                          NULL);
364                 }
365             }
366 
367             // TODO find out why exe_module_sp might be NULL
368             if (!exe_module_sp || exe_module_sp->GetObjectFile() == NULL)
369             {
370                 exe_module_sp.reset();
371                 error.SetErrorStringWithFormat ("'%s' doesn't contain the architecture %s",
372                                                 resolved_module_spec.GetFileSpec().GetPath().c_str(),
373                                                 resolved_module_spec.GetArchitecture().GetArchitectureName());
374             }
375         }
376         else
377         {
378             // No valid architecture was specified, ask the platform for
379             // the architectures that we should be using (in the correct order)
380             // and see if we can find a match that way
381             StreamString arch_names;
382             for (uint32_t idx = 0; GetSupportedArchitectureAtIndex (idx, resolved_module_spec.GetArchitecture()); ++idx)
383             {
384                 error = ModuleList::GetSharedModule (resolved_module_spec,
385                                                      exe_module_sp,
386                                                      NULL,
387                                                      NULL,
388                                                      NULL);
389                 // Did we find an executable using one of the
390                 if (error.Success())
391                 {
392                     if (exe_module_sp && exe_module_sp->GetObjectFile())
393                         break;
394                     else
395                         error.SetErrorToGenericError();
396                 }
397 
398                 if (idx > 0)
399                     arch_names.PutCString (", ");
400                 arch_names.PutCString (resolved_module_spec.GetArchitecture().GetArchitectureName());
401             }
402 
403             if (error.Fail() || !exe_module_sp)
404             {
405                 if (resolved_module_spec.GetFileSpec().Readable())
406                 {
407                     error.SetErrorStringWithFormat ("'%s' doesn't contain any '%s' platform architectures: %s",
408                                                     resolved_module_spec.GetFileSpec().GetPath().c_str(),
409                                                     GetPluginName().GetCString(),
410                                                     arch_names.GetString().c_str());
411                 }
412                 else
413                 {
414                     error.SetErrorStringWithFormat("'%s' is not readable", resolved_module_spec.GetFileSpec().GetPath().c_str());
415                 }
416             }
417         }
418     }
419 
420     return error;
421 }
422 
423 Error
424 PlatformLinux::GetFileWithUUID (const FileSpec &platform_file,
425                                 const UUID *uuid_ptr, FileSpec &local_file)
426 {
427     if (IsRemote())
428     {
429         if (m_remote_platform_sp)
430             return m_remote_platform_sp->GetFileWithUUID (platform_file, uuid_ptr, local_file);
431     }
432 
433     // Default to the local case
434     local_file = platform_file;
435     return Error();
436 }
437 
438 
439 //------------------------------------------------------------------
440 /// Default Constructor
441 //------------------------------------------------------------------
442 PlatformLinux::PlatformLinux (bool is_host) :
443     PlatformPOSIX(is_host)  // This is the local host platform
444 {
445 }
446 
447 //------------------------------------------------------------------
448 /// Destructor.
449 ///
450 /// The destructor is virtual since this class is designed to be
451 /// inherited from by the plug-in instance.
452 //------------------------------------------------------------------
453 PlatformLinux::~PlatformLinux()
454 {
455 }
456 
457 bool
458 PlatformLinux::GetProcessInfo (lldb::pid_t pid, ProcessInstanceInfo &process_info)
459 {
460     bool success = false;
461     if (IsHost())
462     {
463         success = Platform::GetProcessInfo (pid, process_info);
464     }
465     else
466     {
467         if (m_remote_platform_sp)
468             success = m_remote_platform_sp->GetProcessInfo (pid, process_info);
469     }
470     return success;
471 }
472 
473 uint32_t
474 PlatformLinux::FindProcesses (const ProcessInstanceInfoMatch &match_info,
475                               ProcessInstanceInfoList &process_infos)
476 {
477     uint32_t match_count = 0;
478     if (IsHost())
479     {
480         // Let the base class figure out the host details
481         match_count = Platform::FindProcesses (match_info, process_infos);
482     }
483     else
484     {
485         // If we are remote, we can only return results if we are connected
486         if (m_remote_platform_sp)
487             match_count = m_remote_platform_sp->FindProcesses (match_info, process_infos);
488     }
489     return match_count;
490 }
491 
492 bool
493 PlatformLinux::GetSupportedArchitectureAtIndex (uint32_t idx, ArchSpec &arch)
494 {
495     if (idx == 0)
496     {
497         arch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
498         return arch.IsValid();
499     }
500     else if (idx == 1)
501     {
502         // If the default host architecture is 64-bit, look for a 32-bit variant
503         ArchSpec hostArch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
504         if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit())
505         {
506             arch = HostInfo::GetArchitecture(HostInfo::eArchKind32);
507             return arch.IsValid();
508         }
509     }
510     return false;
511 }
512 
513 void
514 PlatformLinux::GetStatus (Stream &strm)
515 {
516     Platform::GetStatus(strm);
517 
518 #ifndef LLDB_DISABLE_POSIX
519     // Display local kernel information only when we are running in host mode.
520     // Otherwise, we would end up printing non-Linux information (when running
521     // on Mac OS for example).
522     if (IsHost())
523     {
524         struct utsname un;
525 
526         if (uname(&un))
527             return;
528 
529         strm.Printf ("    Kernel: %s\n", un.sysname);
530         strm.Printf ("   Release: %s\n", un.release);
531         strm.Printf ("   Version: %s\n", un.version);
532     }
533 #endif
534 }
535 
536 size_t
537 PlatformLinux::GetSoftwareBreakpointTrapOpcode (Target &target,
538                                                 BreakpointSite *bp_site)
539 {
540     ArchSpec arch = target.GetArchitecture();
541     const uint8_t *trap_opcode = NULL;
542     size_t trap_opcode_size = 0;
543 
544     switch (arch.GetMachine())
545     {
546     default:
547         assert(false && "CPU type not supported!");
548         break;
549 
550     case llvm::Triple::aarch64:
551         {
552             static const uint8_t g_aarch64_opcode[] = { 0x00, 0x00, 0x20, 0xd4 };
553             trap_opcode = g_aarch64_opcode;
554             trap_opcode_size = sizeof(g_aarch64_opcode);
555         }
556         break;
557     case llvm::Triple::x86:
558     case llvm::Triple::x86_64:
559         {
560             static const uint8_t g_i386_breakpoint_opcode[] = { 0xCC };
561             trap_opcode = g_i386_breakpoint_opcode;
562             trap_opcode_size = sizeof(g_i386_breakpoint_opcode);
563         }
564         break;
565     case llvm::Triple::hexagon:
566         {
567             static const uint8_t g_hex_opcode[] = { 0x0c, 0xdb, 0x00, 0x54 };
568             trap_opcode = g_hex_opcode;
569             trap_opcode_size = sizeof(g_hex_opcode);
570         }
571         break;
572     case llvm::Triple::arm:
573         {
574             // The ARM reference recommends the use of 0xe7fddefe and 0xdefe
575             // but the linux kernel does otherwise.
576             static const uint8_t g_arm_breakpoint_opcode[] = { 0xf0, 0x01, 0xf0, 0xe7 };
577             static const uint8_t g_thumb_breakpoint_opcode[] = { 0x01, 0xde };
578 
579             lldb::BreakpointLocationSP bp_loc_sp (bp_site->GetOwnerAtIndex (0));
580             AddressClass addr_class = eAddressClassUnknown;
581 
582             if (bp_loc_sp)
583                 addr_class = bp_loc_sp->GetAddress ().GetAddressClass ();
584 
585             if (addr_class == eAddressClassCodeAlternateISA
586                 || (addr_class == eAddressClassUnknown && (bp_site->GetLoadAddress() & 1)))
587             {
588                 trap_opcode = g_thumb_breakpoint_opcode;
589                 trap_opcode_size = sizeof(g_thumb_breakpoint_opcode);
590             }
591             else
592             {
593                 trap_opcode = g_arm_breakpoint_opcode;
594                 trap_opcode_size = sizeof(g_arm_breakpoint_opcode);
595             }
596         }
597         break;
598     case llvm::Triple::mips64:
599         {
600             static const uint8_t g_hex_opcode[] = { 0x00, 0x00, 0x00, 0x0d };
601             trap_opcode = g_hex_opcode;
602             trap_opcode_size = sizeof(g_hex_opcode);
603         }
604         break;
605     case llvm::Triple::mips64el:
606         {
607             static const uint8_t g_hex_opcode[] = { 0x0d, 0x00, 0x00, 0x00 };
608             trap_opcode = g_hex_opcode;
609             trap_opcode_size = sizeof(g_hex_opcode);
610         }
611         break;
612     }
613 
614     if (bp_site->SetTrapOpcode(trap_opcode, trap_opcode_size))
615         return trap_opcode_size;
616     return 0;
617 }
618 
619 int32_t
620 PlatformLinux::GetResumeCountForLaunchInfo (ProcessLaunchInfo &launch_info)
621 {
622     int32_t resume_count = 0;
623 
624     // Always resume past the initial stop when we use eLaunchFlagDebug
625     if (launch_info.GetFlags ().Test (eLaunchFlagDebug))
626     {
627         // Resume past the stop for the final exec into the true inferior.
628         ++resume_count;
629     }
630 
631     // If we're not launching a shell, we're done.
632     const FileSpec &shell = launch_info.GetShell();
633     if (!shell)
634         return resume_count;
635 
636     std::string shell_string = shell.GetPath();
637     // We're in a shell, so for sure we have to resume past the shell exec.
638     ++resume_count;
639 
640     // Figure out what shell we're planning on using.
641     const char *shell_name = strrchr (shell_string.c_str(), '/');
642     if (shell_name == NULL)
643         shell_name = shell_string.c_str();
644     else
645         shell_name++;
646 
647     if (strcmp (shell_name, "csh") == 0
648              || strcmp (shell_name, "tcsh") == 0
649              || strcmp (shell_name, "zsh") == 0
650              || strcmp (shell_name, "sh") == 0)
651     {
652         // These shells seem to re-exec themselves.  Add another resume.
653         ++resume_count;
654     }
655 
656     return resume_count;
657 }
658 
659 bool
660 PlatformLinux::UseLlgsForLocalDebugging ()
661 {
662     PlatformLinuxPropertiesSP properties_sp = GetGlobalProperties ();
663     assert (properties_sp && "global properties shared pointer is null");
664     return properties_sp ? properties_sp->GetUseLlgsForLocal () : false;
665 }
666 
667 bool
668 PlatformLinux::CanDebugProcess ()
669 {
670     if (IsHost ())
671     {
672         // The platform only does local debugging (i.e. uses llgs) when the setting indicates we do that.
673         // Otherwise, we'll use ProcessLinux/ProcessPOSIX to handle with ProcessMonitor.
674         return UseLlgsForLocalDebugging ();
675     }
676     else
677     {
678         // If we're connected, we can debug.
679         return IsConnected ();
680     }
681 }
682 
683 // For local debugging, Linux will override the debug logic to use llgs-launch rather than
684 // lldb-launch, llgs-attach.  This differs from current lldb-launch, debugserver-attach
685 // approach on MacOSX.
686 lldb::ProcessSP
687 PlatformLinux::DebugProcess (ProcessLaunchInfo &launch_info,
688                              Debugger &debugger,
689                              Target *target,       // Can be NULL, if NULL create a new target, else use existing one
690                              Error &error)
691 {
692     Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_PLATFORM));
693     if (log)
694         log->Printf ("PlatformLinux::%s entered (target %p)", __FUNCTION__, static_cast<void*>(target));
695 
696     // If we're a remote host, use standard behavior from parent class.
697     if (!IsHost ())
698         return PlatformPOSIX::DebugProcess (launch_info, debugger, target, error);
699 
700     //
701     // For local debugging, we'll insist on having ProcessGDBRemote create the process.
702     //
703 
704     ProcessSP process_sp;
705 
706     // Ensure we're using llgs for local debugging.
707     if (!UseLlgsForLocalDebugging ())
708     {
709         assert (false && "we're trying to debug a local process but platform.plugin.linux.use-llgs-for-local is false, should never get here");
710         error.SetErrorString ("attempted to start gdb-remote-based debugging for local process but platform.plugin.linux.use-llgs-for-local is false");
711         return process_sp;
712     }
713 
714     // Make sure we stop at the entry point
715     launch_info.GetFlags ().Set (eLaunchFlagDebug);
716 
717     // We always launch the process we are going to debug in a separate process
718     // group, since then we can handle ^C interrupts ourselves w/o having to worry
719     // about the target getting them as well.
720     launch_info.SetLaunchInSeparateProcessGroup(true);
721 
722     // Ensure we have a target.
723     if (target == nullptr)
724     {
725         if (log)
726             log->Printf ("PlatformLinux::%s creating new target", __FUNCTION__);
727 
728         TargetSP new_target_sp;
729         error = debugger.GetTargetList().CreateTarget (debugger,
730                                                        nullptr,
731                                                        nullptr,
732                                                        false,
733                                                        nullptr,
734                                                        new_target_sp);
735         if (error.Fail ())
736         {
737             if (log)
738                 log->Printf ("PlatformLinux::%s failed to create new target: %s", __FUNCTION__, error.AsCString ());
739             return process_sp;
740         }
741 
742         target = new_target_sp.get();
743         if (!target)
744         {
745             error.SetErrorString ("CreateTarget() returned nullptr");
746             if (log)
747                 log->Printf ("PlatformLinux::%s failed: %s", __FUNCTION__, error.AsCString ());
748             return process_sp;
749         }
750     }
751     else
752     {
753         if (log)
754             log->Printf ("PlatformLinux::%s using provided target", __FUNCTION__);
755     }
756 
757     // Mark target as currently selected target.
758     debugger.GetTargetList().SetSelectedTarget(target);
759 
760     // Now create the gdb-remote process.
761     if (log)
762         log->Printf ("PlatformLinux::%s having target create process with gdb-remote plugin", __FUNCTION__);
763     process_sp = target->CreateProcess (launch_info.GetListenerForProcess(debugger), "gdb-remote", nullptr);
764 
765     if (!process_sp)
766     {
767         error.SetErrorString ("CreateProcess() failed for gdb-remote process");
768         if (log)
769             log->Printf ("PlatformLinux::%s failed: %s", __FUNCTION__, error.AsCString ());
770         return process_sp;
771     }
772     else
773     {
774         if (log)
775             log->Printf ("PlatformLinux::%s successfully created process", __FUNCTION__);
776     }
777 
778     // Set the unix signals properly.
779     process_sp->SetUnixSignals (Host::GetUnixSignals ());
780 
781     // Adjust launch for a hijacker.
782     ListenerSP listener_sp;
783     if (!launch_info.GetHijackListener ())
784     {
785         if (log)
786             log->Printf ("PlatformLinux::%s setting up hijacker", __FUNCTION__);
787 
788         listener_sp.reset (new Listener("lldb.PlatformLinux.DebugProcess.hijack"));
789         launch_info.SetHijackListener (listener_sp);
790         process_sp->HijackProcessEvents (listener_sp.get ());
791     }
792 
793     // Log file actions.
794     if (log)
795     {
796         log->Printf ("PlatformLinux::%s launching process with the following file actions:", __FUNCTION__);
797 
798         StreamString stream;
799         size_t i = 0;
800         const FileAction *file_action;
801         while ((file_action = launch_info.GetFileActionAtIndex (i++)) != nullptr)
802         {
803             file_action->Dump (stream);
804             log->PutCString (stream.GetString().c_str ());
805             stream.Clear();
806         }
807     }
808 
809     // Do the launch.
810     error = process_sp->Launch(launch_info);
811     if (error.Success ())
812     {
813         // Handle the hijacking of process events.
814         if (listener_sp)
815         {
816             const StateType state = process_sp->WaitForProcessToStop (NULL, NULL, false, listener_sp.get());
817 
818             if (state == eStateStopped)
819             {
820                 if (log)
821                     log->Printf ("PlatformLinux::%s pid %" PRIu64 " state %s\n",
822                                  __FUNCTION__, process_sp->GetID (), StateAsCString (state));
823             }
824             else
825             {
826                 if (log)
827                     log->Printf ("PlatformLinux::%s pid %" PRIu64 " state is not stopped - %s\n",
828                                  __FUNCTION__, process_sp->GetID (), StateAsCString (state));
829             }
830         }
831 
832         // Hook up process PTY if we have one (which we should for local debugging with llgs).
833         int pty_fd = launch_info.GetPTY().ReleaseMasterFileDescriptor();
834         if (pty_fd != lldb_utility::PseudoTerminal::invalid_fd)
835         {
836             process_sp->SetSTDIOFileDescriptor(pty_fd);
837             if (log)
838                 log->Printf ("PlatformLinux::%s pid %" PRIu64 " hooked up STDIO pty to process", __FUNCTION__, process_sp->GetID ());
839         }
840         else
841         {
842             if (log)
843                 log->Printf ("PlatformLinux::%s pid %" PRIu64 " not using process STDIO pty", __FUNCTION__, process_sp->GetID ());
844         }
845     }
846     else
847     {
848         if (log)
849             log->Printf ("PlatformLinux::%s process launch failed: %s", __FUNCTION__, error.AsCString ());
850         // FIXME figure out appropriate cleanup here.  Do we delete the target? Do we delete the process?  Does our caller do that?
851     }
852 
853     return process_sp;
854 }
855 
856 void
857 PlatformLinux::CalculateTrapHandlerSymbolNames ()
858 {
859     m_trap_handlers.push_back (ConstString ("_sigtramp"));
860 }
861 
862 Error
863 PlatformLinux::LaunchNativeProcess (ProcessLaunchInfo &launch_info,
864                                     NativeProcessProtocol::NativeDelegate &native_delegate,
865                                     NativeProcessProtocolSP &process_sp)
866 {
867 #if !defined(__linux__)
868     return Error("Only implemented on Linux hosts");
869 #else
870     if (!IsHost ())
871         return Error("PlatformLinux::%s (): cannot launch a debug process when not the host", __FUNCTION__);
872 
873     // Retrieve the exe module.
874     lldb::ModuleSP exe_module_sp;
875     ModuleSpec exe_module_spec(launch_info.GetExecutableFile(), launch_info.GetArchitecture());
876 
877     Error error = ResolveExecutable (
878         exe_module_spec,
879         exe_module_sp,
880         NULL);
881 
882     if (!error.Success ())
883         return error;
884 
885     if (!exe_module_sp)
886         return Error("exe_module_sp could not be resolved for %s", launch_info.GetExecutableFile ().GetPath ().c_str ());
887 
888     // Launch it for debugging
889     error = process_linux::NativeProcessLinux::LaunchProcess (
890         exe_module_sp.get (),
891         launch_info,
892         native_delegate,
893         process_sp);
894 
895     return error;
896 #endif
897 }
898 
899 Error
900 PlatformLinux::AttachNativeProcess (lldb::pid_t pid,
901                                     NativeProcessProtocol::NativeDelegate &native_delegate,
902                                     NativeProcessProtocolSP &process_sp)
903 {
904 #if !defined(__linux__)
905     return Error("Only implemented on Linux hosts");
906 #else
907     if (!IsHost ())
908         return Error("PlatformLinux::%s (): cannot attach to a debug process when not the host", __FUNCTION__);
909 
910     // Launch it for debugging
911     return process_linux::NativeProcessLinux::AttachToProcess (pid, native_delegate, process_sp);
912 #endif
913 }
914