1 //===-- TargetList.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 // C Includes
13 // C++ Includes
14 // Other libraries and framework includes
15 // Project includes
16 #include "lldb/Core/Broadcaster.h"
17 #include "lldb/Core/Debugger.h"
18 #include "lldb/Core/Event.h"
19 #include "lldb/Core/Module.h"
20 #include "lldb/Core/ModuleSpec.h"
21 #include "lldb/Core/State.h"
22 #include "lldb/Core/Timer.h"
23 #include "lldb/Host/Host.h"
24 #include "lldb/Host/HostInfo.h"
25 #include "lldb/Interpreter/CommandInterpreter.h"
26 #include "lldb/Interpreter/OptionGroupPlatform.h"
27 #include "lldb/Symbol/ObjectFile.h"
28 #include "lldb/Target/Platform.h"
29 #include "lldb/Target/Process.h"
30 #include "lldb/Target/TargetList.h"
31 
32 #include "llvm/ADT/SmallString.h"
33 
34 using namespace lldb;
35 using namespace lldb_private;
36 
37 ConstString &
38 TargetList::GetStaticBroadcasterClass ()
39 {
40     static ConstString class_name ("lldb.targetList");
41     return class_name;
42 }
43 
44 //----------------------------------------------------------------------
45 // TargetList constructor
46 //----------------------------------------------------------------------
47 TargetList::TargetList(Debugger &debugger) :
48     Broadcaster(&debugger, TargetList::GetStaticBroadcasterClass().AsCString()),
49     m_target_list(),
50     m_target_list_mutex (Mutex::eMutexTypeRecursive),
51     m_selected_target_idx (0)
52 {
53     CheckInWithManager();
54 }
55 
56 //----------------------------------------------------------------------
57 // Destructor
58 //----------------------------------------------------------------------
59 TargetList::~TargetList()
60 {
61     Mutex::Locker locker(m_target_list_mutex);
62     m_target_list.clear();
63 }
64 
65 Error
66 TargetList::CreateTarget (Debugger &debugger,
67                           const char *user_exe_path,
68                           const char *triple_cstr,
69                           bool get_dependent_files,
70                           const OptionGroupPlatform *platform_options,
71                           TargetSP &target_sp)
72 {
73     return CreateTargetInternal (debugger,
74                                  user_exe_path,
75                                  triple_cstr,
76                                  get_dependent_files,
77                                  platform_options,
78                                  target_sp,
79                                  false);
80 }
81 
82 Error
83 TargetList::CreateTarget (Debugger &debugger,
84                           const char *user_exe_path,
85                           const ArchSpec& specified_arch,
86                           bool get_dependent_files,
87                           PlatformSP &platform_sp,
88                           TargetSP &target_sp)
89 {
90     return CreateTargetInternal (debugger,
91                                  user_exe_path,
92                                  specified_arch,
93                                  get_dependent_files,
94                                  platform_sp,
95                                  target_sp,
96                                  false);
97 }
98 
99 Error
100 TargetList::CreateTargetInternal (Debugger &debugger,
101                                   const char *user_exe_path,
102                                   const char *triple_cstr,
103                                   bool get_dependent_files,
104                                   const OptionGroupPlatform *platform_options,
105                                   TargetSP &target_sp,
106                                   bool is_dummy_target)
107 {
108     Error error;
109     PlatformSP platform_sp;
110 
111     // This is purposely left empty unless it is specified by triple_cstr.
112     // If not initialized via triple_cstr, then the currently selected platform
113     // will set the architecture correctly.
114     const ArchSpec arch(triple_cstr);
115     if (triple_cstr && triple_cstr[0])
116     {
117         if (!arch.IsValid())
118         {
119             error.SetErrorStringWithFormat("invalid triple '%s'", triple_cstr);
120             return error;
121         }
122     }
123 
124     ArchSpec platform_arch(arch);
125 
126     bool prefer_platform_arch = false;
127 
128     CommandInterpreter &interpreter = debugger.GetCommandInterpreter();
129 
130     // let's see if there is already an existing plaform before we go creating another...
131     platform_sp = debugger.GetPlatformList().GetSelectedPlatform();
132 
133     if (platform_options && platform_options->PlatformWasSpecified ())
134     {
135         // Create a new platform if it doesn't match the selected platform
136         if (!platform_options->PlatformMatches(platform_sp))
137         {
138             const bool select_platform = true;
139             platform_sp = platform_options->CreatePlatformWithOptions (interpreter,
140                                                                        arch,
141                                                                        select_platform,
142                                                                        error,
143                                                                        platform_arch);
144             if (!platform_sp)
145                 return error;
146         }
147     }
148 
149     if (user_exe_path && user_exe_path[0])
150     {
151         ModuleSpecList module_specs;
152         ModuleSpec module_spec;
153         module_spec.GetFileSpec().SetFile(user_exe_path, true);
154 
155         // Resolve the executable in case we are given a path to a application bundle
156         // like a .app bundle on MacOSX
157         Host::ResolveExecutableInBundle (module_spec.GetFileSpec());
158 
159         lldb::offset_t file_offset = 0;
160         lldb::offset_t file_size = 0;
161         const size_t num_specs = ObjectFile::GetModuleSpecifications (module_spec.GetFileSpec(), file_offset, file_size, module_specs);
162         if (num_specs > 0)
163         {
164             ModuleSpec matching_module_spec;
165 
166             if (num_specs == 1)
167             {
168                 if (module_specs.GetModuleSpecAtIndex(0, matching_module_spec))
169                 {
170                     if (platform_arch.IsValid())
171                     {
172                         if (platform_arch.IsCompatibleMatch(matching_module_spec.GetArchitecture()))
173                         {
174                             // If the OS or vendor weren't specified, then adopt the module's
175                             // architecture so that the platform matching can be more accurate
176                             if (!platform_arch.TripleOSWasSpecified() || !platform_arch.TripleVendorWasSpecified())
177                             {
178                                 prefer_platform_arch = true;
179                                 platform_arch = matching_module_spec.GetArchitecture();
180                             }
181                         }
182                         else
183                         {
184                             error.SetErrorStringWithFormat("the specified architecture '%s' is not compatible with '%s' in '%s'",
185                                                            platform_arch.GetTriple().str().c_str(),
186                                                            matching_module_spec.GetArchitecture().GetTriple().str().c_str(),
187                                                            module_spec.GetFileSpec().GetPath().c_str());
188                             return error;
189                         }
190                     }
191                     else
192                     {
193                         // Only one arch and none was specified
194                         prefer_platform_arch = true;
195                         platform_arch = matching_module_spec.GetArchitecture();
196                     }
197                 }
198             }
199             else
200             {
201                 if (arch.IsValid())
202                 {
203                     module_spec.GetArchitecture() = arch;
204                     if (module_specs.FindMatchingModuleSpec(module_spec, matching_module_spec))
205                     {
206                         prefer_platform_arch = true;
207                         platform_arch = matching_module_spec.GetArchitecture();
208                     }
209                 }
210                 else
211                 {
212                     // No architecture specified, check if there is only one platform for
213                     // all of the architectures.
214 
215                     typedef std::vector<PlatformSP> PlatformList;
216                     PlatformList platforms;
217                     PlatformSP host_platform_sp = Platform::GetHostPlatform();
218                     for (size_t i=0; i<num_specs; ++i)
219                     {
220                         ModuleSpec module_spec;
221                         if (module_specs.GetModuleSpecAtIndex(i, module_spec))
222                         {
223                             // See if there was a selected platform and check that first
224                             // since the user may have specified it.
225                             if (platform_sp)
226                             {
227                                 if (platform_sp->IsCompatibleArchitecture(module_spec.GetArchitecture(), false, NULL))
228                                 {
229                                     platforms.push_back(platform_sp);
230                                     continue;
231                                 }
232                             }
233 
234                             // Next check the host platform it if wasn't already checked above
235                             if (host_platform_sp && (!platform_sp || host_platform_sp->GetName() != platform_sp->GetName()))
236                             {
237                                 if (host_platform_sp->IsCompatibleArchitecture(module_spec.GetArchitecture(), false, NULL))
238                                 {
239                                     platforms.push_back(host_platform_sp);
240                                     continue;
241                                 }
242                             }
243 
244                             // Just find a platform that matches the architecture in the executable file
245                             platforms.push_back(Platform::GetPlatformForArchitecture(module_spec.GetArchitecture(), nullptr));
246                         }
247                     }
248 
249                     Platform *platform_ptr = NULL;
250                     for (const auto &the_platform_sp : platforms)
251                     {
252                         if (platform_ptr)
253                         {
254                             if (platform_ptr->GetName() != the_platform_sp->GetName())
255                             {
256                                 platform_ptr = NULL;
257                                 break;
258                             }
259                         }
260                         else
261                         {
262                             platform_ptr = the_platform_sp.get();
263                         }
264                     }
265 
266                     if (platform_ptr)
267                     {
268                         // All platforms for all modules in the exectuable match, so we can select this platform
269                         platform_sp = platforms.front();
270                     }
271                     else
272                     {
273                         // More than one platform claims to support this file, so the --platform option must be specified
274                         StreamString error_strm;
275                         std::set<Platform *> platform_set;
276                         error_strm.Printf ("more than one platform supports this executable (");
277                         for (const auto &the_platform_sp : platforms)
278                         {
279                             if (platform_set.find(the_platform_sp.get()) == platform_set.end())
280                             {
281                                 if (!platform_set.empty())
282                                     error_strm.PutCString(", ");
283                                 error_strm.PutCString(the_platform_sp->GetName().GetCString());
284                                 platform_set.insert(the_platform_sp.get());
285                             }
286                         }
287                         error_strm.Printf("), use the --platform option to specify a platform");
288                         error.SetErrorString(error_strm.GetString().c_str());
289                         return error;
290                     }
291                 }
292             }
293         }
294     }
295 
296     if (!platform_sp)
297     {
298         // Get the current platform and make sure it is compatible with the
299         // current architecture if we have a valid architecture.
300         platform_sp = debugger.GetPlatformList().GetSelectedPlatform ();
301 
302         if (!prefer_platform_arch && arch.IsValid())
303         {
304             if (!platform_sp->IsCompatibleArchitecture(arch, false, &platform_arch))
305             {
306                 platform_sp = Platform::GetPlatformForArchitecture(arch, &platform_arch);
307                 if (platform_sp)
308                     debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
309             }
310         }
311         else if (platform_arch.IsValid())
312         {
313             // if "arch" isn't valid, yet "platform_arch" is, it means we have an executable file with
314             // a single architecture which should be used
315             ArchSpec fixed_platform_arch;
316             if (!platform_sp->IsCompatibleArchitecture(platform_arch, false, &fixed_platform_arch))
317             {
318                 platform_sp = Platform::GetPlatformForArchitecture(platform_arch, &fixed_platform_arch);
319                 if (platform_sp)
320                     debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
321             }
322         }
323     }
324 
325     if (!platform_arch.IsValid())
326         platform_arch = arch;
327 
328     error = TargetList::CreateTargetInternal (debugger,
329                                               user_exe_path,
330                                               platform_arch,
331                                               get_dependent_files,
332                                               platform_sp,
333                                               target_sp,
334                                               is_dummy_target);
335     return error;
336 }
337 
338 lldb::TargetSP
339 TargetList::GetDummyTarget (lldb_private::Debugger &debugger)
340 {
341     // FIXME: Maybe the dummy target should be per-Debugger
342     if (!m_dummy_target_sp || !m_dummy_target_sp->IsValid())
343     {
344         ArchSpec arch(Target::GetDefaultArchitecture());
345         if (!arch.IsValid())
346             arch = HostInfo::GetArchitecture();
347         Error err = CreateDummyTarget(debugger,
348                                       arch.GetTriple().getTriple().c_str(),
349                                       m_dummy_target_sp);
350     }
351 
352     return m_dummy_target_sp;
353 }
354 
355 Error
356 TargetList::CreateDummyTarget (Debugger &debugger,
357                                const char *specified_arch_name,
358                                lldb::TargetSP &target_sp)
359 {
360     PlatformSP host_platform_sp(Platform::GetHostPlatform());
361     return CreateTargetInternal (debugger,
362                                  (const char *) nullptr,
363                                  specified_arch_name,
364                                  false,
365                                  (const OptionGroupPlatform *) nullptr,
366                                  target_sp,
367                                  true);
368 }
369 
370 Error
371 TargetList::CreateTargetInternal (Debugger &debugger,
372                                   const char *user_exe_path,
373                                   const ArchSpec& specified_arch,
374                                   bool get_dependent_files,
375                                   lldb::PlatformSP &platform_sp,
376                                   lldb::TargetSP &target_sp,
377                                   bool is_dummy_target)
378 {
379 
380     Timer scoped_timer (__PRETTY_FUNCTION__,
381                         "TargetList::CreateTarget (file = '%s', arch = '%s')",
382                         user_exe_path,
383                         specified_arch.GetArchitectureName());
384     Error error;
385 
386     ArchSpec arch(specified_arch);
387 
388     if (arch.IsValid())
389     {
390         if (!platform_sp || !platform_sp->IsCompatibleArchitecture(arch, false, NULL))
391             platform_sp = Platform::GetPlatformForArchitecture(specified_arch, &arch);
392     }
393 
394     if (!platform_sp)
395         platform_sp = debugger.GetPlatformList().GetSelectedPlatform();
396 
397     if (!arch.IsValid())
398         arch = specified_arch;
399 
400     FileSpec file (user_exe_path, false);
401     if (!file.Exists() && user_exe_path && user_exe_path[0] == '~')
402     {
403         // we want to expand the tilde but we don't want to resolve any symbolic links
404         // so we can't use the FileSpec constructor's resolve flag
405         llvm::SmallString<64> unglobbed_path(user_exe_path);
406         FileSpec::ResolveUsername(unglobbed_path);
407 
408         if (unglobbed_path.empty())
409             file = FileSpec(user_exe_path, false);
410         else
411             file = FileSpec(unglobbed_path.c_str(), false);
412     }
413 
414     bool user_exe_path_is_bundle = false;
415     char resolved_bundle_exe_path[PATH_MAX];
416     resolved_bundle_exe_path[0] = '\0';
417     if (file)
418     {
419         if (file.GetFileType() == FileSpec::eFileTypeDirectory)
420             user_exe_path_is_bundle = true;
421 
422         if (file.IsRelativeToCurrentWorkingDirectory() && user_exe_path)
423         {
424             // Ignore paths that start with "./" and "../"
425             if (!((user_exe_path[0] == '.' && user_exe_path[1] == '/') ||
426                   (user_exe_path[0] == '.' && user_exe_path[1] == '.' && user_exe_path[2] == '/')))
427             {
428                 char cwd[PATH_MAX];
429                 if (getcwd (cwd, sizeof(cwd)))
430                 {
431                     std::string cwd_user_exe_path (cwd);
432                     cwd_user_exe_path += '/';
433                     cwd_user_exe_path += user_exe_path;
434                     FileSpec cwd_file (cwd_user_exe_path.c_str(), false);
435                     if (cwd_file.Exists())
436                         file = cwd_file;
437                 }
438             }
439         }
440 
441         ModuleSP exe_module_sp;
442         if (platform_sp)
443         {
444             FileSpecList executable_search_paths (Target::GetDefaultExecutableSearchPaths());
445             ModuleSpec module_spec(file, arch);
446             error = platform_sp->ResolveExecutable (module_spec,
447                                                     exe_module_sp,
448                                                     executable_search_paths.GetSize() ? &executable_search_paths : NULL);
449         }
450 
451         if (error.Success() && exe_module_sp)
452         {
453             if (exe_module_sp->GetObjectFile() == NULL)
454             {
455                 if (arch.IsValid())
456                 {
457                     error.SetErrorStringWithFormat("\"%s\" doesn't contain architecture %s",
458                                                    file.GetPath().c_str(),
459                                                    arch.GetArchitectureName());
460                 }
461                 else
462                 {
463                     error.SetErrorStringWithFormat("unsupported file type \"%s\"",
464                                                    file.GetPath().c_str());
465                 }
466                 return error;
467             }
468             target_sp.reset(new Target(debugger, arch, platform_sp, is_dummy_target));
469             target_sp->SetExecutableModule (exe_module_sp, get_dependent_files);
470             if (user_exe_path_is_bundle)
471                 exe_module_sp->GetFileSpec().GetPath(resolved_bundle_exe_path, sizeof(resolved_bundle_exe_path));
472         }
473     }
474     else
475     {
476         // No file was specified, just create an empty target with any arch
477         // if a valid arch was specified
478         target_sp.reset(new Target(debugger, arch, platform_sp, is_dummy_target));
479     }
480 
481     if (target_sp)
482     {
483         // Set argv0 with what the user typed, unless the user specified a
484         // directory. If the user specified a directory, then it is probably a
485         // bundle that was resolved and we need to use the resolved bundle path
486         if (user_exe_path)
487         {
488             // Use exactly what the user typed as the first argument when we exec or posix_spawn
489             if (user_exe_path_is_bundle && resolved_bundle_exe_path[0])
490             {
491                 target_sp->SetArg0 (resolved_bundle_exe_path);
492             }
493             else
494             {
495                 // Use resolved path
496                 target_sp->SetArg0 (file.GetPath().c_str());
497             }
498         }
499         if (file.GetDirectory())
500         {
501             FileSpec file_dir;
502             file_dir.GetDirectory() = file.GetDirectory();
503             target_sp->GetExecutableSearchPaths ().Append (file_dir);
504         }
505 
506         // Don't put the dummy target in the target list, it's held separately.
507         if (!is_dummy_target)
508         {
509             Mutex::Locker locker(m_target_list_mutex);
510             m_selected_target_idx = m_target_list.size();
511             m_target_list.push_back(target_sp);
512             // Now prime this from the dummy target:
513             target_sp->PrimeFromDummyTarget(debugger.GetDummyTarget());
514         }
515         else
516         {
517             m_dummy_target_sp = target_sp;
518         }
519     }
520 
521     return error;
522 }
523 
524 bool
525 TargetList::DeleteTarget (TargetSP &target_sp)
526 {
527     Mutex::Locker locker(m_target_list_mutex);
528     collection::iterator pos, end = m_target_list.end();
529 
530     for (pos = m_target_list.begin(); pos != end; ++pos)
531     {
532         if (pos->get() == target_sp.get())
533         {
534             m_target_list.erase(pos);
535             return true;
536         }
537     }
538     return false;
539 }
540 
541 
542 TargetSP
543 TargetList::FindTargetWithExecutableAndArchitecture
544 (
545     const FileSpec &exe_file_spec,
546     const ArchSpec *exe_arch_ptr
547 ) const
548 {
549     Mutex::Locker locker (m_target_list_mutex);
550     TargetSP target_sp;
551     bool full_match = (bool)exe_file_spec.GetDirectory();
552 
553     collection::const_iterator pos, end = m_target_list.end();
554     for (pos = m_target_list.begin(); pos != end; ++pos)
555     {
556         Module *exe_module = (*pos)->GetExecutableModulePointer();
557 
558         if (exe_module)
559         {
560             if (FileSpec::Equal (exe_file_spec, exe_module->GetFileSpec(), full_match))
561             {
562                 if (exe_arch_ptr)
563                 {
564                     if (!exe_arch_ptr->IsCompatibleMatch(exe_module->GetArchitecture()))
565                         continue;
566                 }
567                 target_sp = *pos;
568                 break;
569             }
570         }
571     }
572     return target_sp;
573 }
574 
575 TargetSP
576 TargetList::FindTargetWithProcessID (lldb::pid_t pid) const
577 {
578     Mutex::Locker locker(m_target_list_mutex);
579     TargetSP target_sp;
580     collection::const_iterator pos, end = m_target_list.end();
581     for (pos = m_target_list.begin(); pos != end; ++pos)
582     {
583         Process* process = (*pos)->GetProcessSP().get();
584         if (process && process->GetID() == pid)
585         {
586             target_sp = *pos;
587             break;
588         }
589     }
590     return target_sp;
591 }
592 
593 
594 TargetSP
595 TargetList::FindTargetWithProcess (Process *process) const
596 {
597     TargetSP target_sp;
598     if (process)
599     {
600         Mutex::Locker locker(m_target_list_mutex);
601         collection::const_iterator pos, end = m_target_list.end();
602         for (pos = m_target_list.begin(); pos != end; ++pos)
603         {
604             if (process == (*pos)->GetProcessSP().get())
605             {
606                 target_sp = *pos;
607                 break;
608             }
609         }
610     }
611     return target_sp;
612 }
613 
614 TargetSP
615 TargetList::GetTargetSP (Target *target) const
616 {
617     TargetSP target_sp;
618     if (target)
619     {
620         Mutex::Locker locker(m_target_list_mutex);
621         collection::const_iterator pos, end = m_target_list.end();
622         for (pos = m_target_list.begin(); pos != end; ++pos)
623         {
624             if (target == (*pos).get())
625             {
626                 target_sp = *pos;
627                 break;
628             }
629         }
630     }
631     return target_sp;
632 }
633 
634 uint32_t
635 TargetList::SendAsyncInterrupt (lldb::pid_t pid)
636 {
637     uint32_t num_async_interrupts_sent = 0;
638 
639     if (pid != LLDB_INVALID_PROCESS_ID)
640     {
641         TargetSP target_sp(FindTargetWithProcessID (pid));
642         if (target_sp.get())
643         {
644             Process* process = target_sp->GetProcessSP().get();
645             if (process)
646             {
647                 process->SendAsyncInterrupt();
648                 ++num_async_interrupts_sent;
649             }
650         }
651     }
652     else
653     {
654         // We don't have a valid pid to broadcast to, so broadcast to the target
655         // list's async broadcaster...
656         BroadcastEvent (Process::eBroadcastBitInterrupt, NULL);
657     }
658 
659     return num_async_interrupts_sent;
660 }
661 
662 uint32_t
663 TargetList::SignalIfRunning (lldb::pid_t pid, int signo)
664 {
665     uint32_t num_signals_sent = 0;
666     Process *process = NULL;
667     if (pid == LLDB_INVALID_PROCESS_ID)
668     {
669         // Signal all processes with signal
670         Mutex::Locker locker(m_target_list_mutex);
671         collection::iterator pos, end = m_target_list.end();
672         for (pos = m_target_list.begin(); pos != end; ++pos)
673         {
674             process = (*pos)->GetProcessSP().get();
675             if (process)
676             {
677                 if (process->IsAlive())
678                 {
679                     ++num_signals_sent;
680                     process->Signal (signo);
681                 }
682             }
683         }
684     }
685     else
686     {
687         // Signal a specific process with signal
688         TargetSP target_sp(FindTargetWithProcessID (pid));
689         if (target_sp.get())
690         {
691             process = target_sp->GetProcessSP().get();
692             if (process)
693             {
694                 if (process->IsAlive())
695                 {
696                     ++num_signals_sent;
697                     process->Signal (signo);
698                 }
699             }
700         }
701     }
702     return num_signals_sent;
703 }
704 
705 int
706 TargetList::GetNumTargets () const
707 {
708     Mutex::Locker locker (m_target_list_mutex);
709     return m_target_list.size();
710 }
711 
712 lldb::TargetSP
713 TargetList::GetTargetAtIndex (uint32_t idx) const
714 {
715     TargetSP target_sp;
716     Mutex::Locker locker (m_target_list_mutex);
717     if (idx < m_target_list.size())
718         target_sp = m_target_list[idx];
719     return target_sp;
720 }
721 
722 uint32_t
723 TargetList::GetIndexOfTarget (lldb::TargetSP target_sp) const
724 {
725     Mutex::Locker locker (m_target_list_mutex);
726     size_t num_targets = m_target_list.size();
727     for (size_t idx = 0; idx < num_targets; idx++)
728     {
729         if (target_sp == m_target_list[idx])
730             return idx;
731     }
732     return UINT32_MAX;
733 }
734 
735 uint32_t
736 TargetList::SetSelectedTarget (Target* target)
737 {
738     Mutex::Locker locker (m_target_list_mutex);
739     collection::const_iterator pos,
740         begin = m_target_list.begin(),
741         end = m_target_list.end();
742     for (pos = begin; pos != end; ++pos)
743     {
744         if (pos->get() == target)
745         {
746             m_selected_target_idx = std::distance (begin, pos);
747             return m_selected_target_idx;
748         }
749     }
750     m_selected_target_idx = 0;
751     return m_selected_target_idx;
752 }
753 
754 lldb::TargetSP
755 TargetList::GetSelectedTarget ()
756 {
757     Mutex::Locker locker (m_target_list_mutex);
758     if (m_selected_target_idx >= m_target_list.size())
759         m_selected_target_idx = 0;
760     return GetTargetAtIndex (m_selected_target_idx);
761 }
762