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 we have a valid architecture, make sure the current platform is
297     // compatible with that architecture
298     if (!prefer_platform_arch && arch.IsValid())
299     {
300         if (!platform_sp->IsCompatibleArchitecture(arch, false, &platform_arch))
301         {
302             platform_sp = Platform::GetPlatformForArchitecture(arch, &platform_arch);
303             if (!is_dummy_target && platform_sp)
304                 debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
305         }
306     }
307     else if (platform_arch.IsValid())
308     {
309         // if "arch" isn't valid, yet "platform_arch" is, it means we have an executable file with
310         // a single architecture which should be used
311         ArchSpec fixed_platform_arch;
312         if (!platform_sp->IsCompatibleArchitecture(platform_arch, false, &fixed_platform_arch))
313         {
314             platform_sp = Platform::GetPlatformForArchitecture(platform_arch, &fixed_platform_arch);
315             if (!is_dummy_target && platform_sp)
316                 debugger.GetPlatformList().SetSelectedPlatform(platform_sp);
317         }
318     }
319 
320     if (!platform_arch.IsValid())
321         platform_arch = arch;
322 
323     error = TargetList::CreateTargetInternal (debugger,
324                                               user_exe_path,
325                                               platform_arch,
326                                               get_dependent_files,
327                                               platform_sp,
328                                               target_sp,
329                                               is_dummy_target);
330     return error;
331 }
332 
333 lldb::TargetSP
334 TargetList::GetDummyTarget (lldb_private::Debugger &debugger)
335 {
336     // FIXME: Maybe the dummy target should be per-Debugger
337     if (!m_dummy_target_sp || !m_dummy_target_sp->IsValid())
338     {
339         ArchSpec arch(Target::GetDefaultArchitecture());
340         if (!arch.IsValid())
341             arch = HostInfo::GetArchitecture();
342         Error err = CreateDummyTarget(debugger,
343                                       arch.GetTriple().getTriple().c_str(),
344                                       m_dummy_target_sp);
345     }
346 
347     return m_dummy_target_sp;
348 }
349 
350 Error
351 TargetList::CreateDummyTarget (Debugger &debugger,
352                                const char *specified_arch_name,
353                                lldb::TargetSP &target_sp)
354 {
355     PlatformSP host_platform_sp(Platform::GetHostPlatform());
356     return CreateTargetInternal (debugger,
357                                  (const char *) nullptr,
358                                  specified_arch_name,
359                                  false,
360                                  (const OptionGroupPlatform *) nullptr,
361                                  target_sp,
362                                  true);
363 }
364 
365 Error
366 TargetList::CreateTargetInternal (Debugger &debugger,
367                                   const char *user_exe_path,
368                                   const ArchSpec& specified_arch,
369                                   bool get_dependent_files,
370                                   lldb::PlatformSP &platform_sp,
371                                   lldb::TargetSP &target_sp,
372                                   bool is_dummy_target)
373 {
374 
375     Timer scoped_timer (__PRETTY_FUNCTION__,
376                         "TargetList::CreateTarget (file = '%s', arch = '%s')",
377                         user_exe_path,
378                         specified_arch.GetArchitectureName());
379     Error error;
380 
381     ArchSpec arch(specified_arch);
382 
383     if (arch.IsValid())
384     {
385         if (!platform_sp || !platform_sp->IsCompatibleArchitecture(arch, false, NULL))
386             platform_sp = Platform::GetPlatformForArchitecture(specified_arch, &arch);
387     }
388 
389     if (!platform_sp)
390         platform_sp = debugger.GetPlatformList().GetSelectedPlatform();
391 
392     if (!arch.IsValid())
393         arch = specified_arch;
394 
395     FileSpec file (user_exe_path, false);
396     if (!file.Exists() && user_exe_path && user_exe_path[0] == '~')
397     {
398         // we want to expand the tilde but we don't want to resolve any symbolic links
399         // so we can't use the FileSpec constructor's resolve flag
400         llvm::SmallString<64> unglobbed_path(user_exe_path);
401         FileSpec::ResolveUsername(unglobbed_path);
402 
403         if (unglobbed_path.empty())
404             file = FileSpec(user_exe_path, false);
405         else
406             file = FileSpec(unglobbed_path.c_str(), false);
407     }
408 
409     bool user_exe_path_is_bundle = false;
410     char resolved_bundle_exe_path[PATH_MAX];
411     resolved_bundle_exe_path[0] = '\0';
412     if (file)
413     {
414         if (file.GetFileType() == FileSpec::eFileTypeDirectory)
415             user_exe_path_is_bundle = true;
416 
417         if (file.IsRelativeToCurrentWorkingDirectory() && user_exe_path)
418         {
419             // Ignore paths that start with "./" and "../"
420             if (!((user_exe_path[0] == '.' && user_exe_path[1] == '/') ||
421                   (user_exe_path[0] == '.' && user_exe_path[1] == '.' && user_exe_path[2] == '/')))
422             {
423                 char cwd[PATH_MAX];
424                 if (getcwd (cwd, sizeof(cwd)))
425                 {
426                     std::string cwd_user_exe_path (cwd);
427                     cwd_user_exe_path += '/';
428                     cwd_user_exe_path += user_exe_path;
429                     FileSpec cwd_file (cwd_user_exe_path.c_str(), false);
430                     if (cwd_file.Exists())
431                         file = cwd_file;
432                 }
433             }
434         }
435 
436         ModuleSP exe_module_sp;
437         if (platform_sp)
438         {
439             FileSpecList executable_search_paths (Target::GetDefaultExecutableSearchPaths());
440             ModuleSpec module_spec(file, arch);
441             error = platform_sp->ResolveExecutable (module_spec,
442                                                     exe_module_sp,
443                                                     executable_search_paths.GetSize() ? &executable_search_paths : NULL);
444         }
445 
446         if (error.Success() && exe_module_sp)
447         {
448             if (exe_module_sp->GetObjectFile() == NULL)
449             {
450                 if (arch.IsValid())
451                 {
452                     error.SetErrorStringWithFormat("\"%s\" doesn't contain architecture %s",
453                                                    file.GetPath().c_str(),
454                                                    arch.GetArchitectureName());
455                 }
456                 else
457                 {
458                     error.SetErrorStringWithFormat("unsupported file type \"%s\"",
459                                                    file.GetPath().c_str());
460                 }
461                 return error;
462             }
463             target_sp.reset(new Target(debugger, arch, platform_sp, is_dummy_target));
464             target_sp->SetExecutableModule (exe_module_sp, get_dependent_files);
465             if (user_exe_path_is_bundle)
466                 exe_module_sp->GetFileSpec().GetPath(resolved_bundle_exe_path, sizeof(resolved_bundle_exe_path));
467         }
468     }
469     else
470     {
471         // No file was specified, just create an empty target with any arch
472         // if a valid arch was specified
473         target_sp.reset(new Target(debugger, arch, platform_sp, is_dummy_target));
474     }
475 
476     if (target_sp)
477     {
478         // Set argv0 with what the user typed, unless the user specified a
479         // directory. If the user specified a directory, then it is probably a
480         // bundle that was resolved and we need to use the resolved bundle path
481         if (user_exe_path)
482         {
483             // Use exactly what the user typed as the first argument when we exec or posix_spawn
484             if (user_exe_path_is_bundle && resolved_bundle_exe_path[0])
485             {
486                 target_sp->SetArg0 (resolved_bundle_exe_path);
487             }
488             else
489             {
490                 // Use resolved path
491                 target_sp->SetArg0 (file.GetPath().c_str());
492             }
493         }
494         if (file.GetDirectory())
495         {
496             FileSpec file_dir;
497             file_dir.GetDirectory() = file.GetDirectory();
498             target_sp->GetExecutableSearchPaths ().Append (file_dir);
499         }
500 
501         // Don't put the dummy target in the target list, it's held separately.
502         if (!is_dummy_target)
503         {
504             Mutex::Locker locker(m_target_list_mutex);
505             m_selected_target_idx = m_target_list.size();
506             m_target_list.push_back(target_sp);
507             // Now prime this from the dummy target:
508             target_sp->PrimeFromDummyTarget(debugger.GetDummyTarget());
509         }
510         else
511         {
512             m_dummy_target_sp = target_sp;
513         }
514     }
515 
516     return error;
517 }
518 
519 bool
520 TargetList::DeleteTarget (TargetSP &target_sp)
521 {
522     Mutex::Locker locker(m_target_list_mutex);
523     collection::iterator pos, end = m_target_list.end();
524 
525     for (pos = m_target_list.begin(); pos != end; ++pos)
526     {
527         if (pos->get() == target_sp.get())
528         {
529             m_target_list.erase(pos);
530             return true;
531         }
532     }
533     return false;
534 }
535 
536 
537 TargetSP
538 TargetList::FindTargetWithExecutableAndArchitecture
539 (
540     const FileSpec &exe_file_spec,
541     const ArchSpec *exe_arch_ptr
542 ) const
543 {
544     Mutex::Locker locker (m_target_list_mutex);
545     TargetSP target_sp;
546     bool full_match = (bool)exe_file_spec.GetDirectory();
547 
548     collection::const_iterator pos, end = m_target_list.end();
549     for (pos = m_target_list.begin(); pos != end; ++pos)
550     {
551         Module *exe_module = (*pos)->GetExecutableModulePointer();
552 
553         if (exe_module)
554         {
555             if (FileSpec::Equal (exe_file_spec, exe_module->GetFileSpec(), full_match))
556             {
557                 if (exe_arch_ptr)
558                 {
559                     if (!exe_arch_ptr->IsCompatibleMatch(exe_module->GetArchitecture()))
560                         continue;
561                 }
562                 target_sp = *pos;
563                 break;
564             }
565         }
566     }
567     return target_sp;
568 }
569 
570 TargetSP
571 TargetList::FindTargetWithProcessID (lldb::pid_t pid) const
572 {
573     Mutex::Locker locker(m_target_list_mutex);
574     TargetSP target_sp;
575     collection::const_iterator pos, end = m_target_list.end();
576     for (pos = m_target_list.begin(); pos != end; ++pos)
577     {
578         Process* process = (*pos)->GetProcessSP().get();
579         if (process && process->GetID() == pid)
580         {
581             target_sp = *pos;
582             break;
583         }
584     }
585     return target_sp;
586 }
587 
588 
589 TargetSP
590 TargetList::FindTargetWithProcess (Process *process) const
591 {
592     TargetSP target_sp;
593     if (process)
594     {
595         Mutex::Locker locker(m_target_list_mutex);
596         collection::const_iterator pos, end = m_target_list.end();
597         for (pos = m_target_list.begin(); pos != end; ++pos)
598         {
599             if (process == (*pos)->GetProcessSP().get())
600             {
601                 target_sp = *pos;
602                 break;
603             }
604         }
605     }
606     return target_sp;
607 }
608 
609 TargetSP
610 TargetList::GetTargetSP (Target *target) const
611 {
612     TargetSP target_sp;
613     if (target)
614     {
615         Mutex::Locker locker(m_target_list_mutex);
616         collection::const_iterator pos, end = m_target_list.end();
617         for (pos = m_target_list.begin(); pos != end; ++pos)
618         {
619             if (target == (*pos).get())
620             {
621                 target_sp = *pos;
622                 break;
623             }
624         }
625     }
626     return target_sp;
627 }
628 
629 uint32_t
630 TargetList::SendAsyncInterrupt (lldb::pid_t pid)
631 {
632     uint32_t num_async_interrupts_sent = 0;
633 
634     if (pid != LLDB_INVALID_PROCESS_ID)
635     {
636         TargetSP target_sp(FindTargetWithProcessID (pid));
637         if (target_sp.get())
638         {
639             Process* process = target_sp->GetProcessSP().get();
640             if (process)
641             {
642                 process->SendAsyncInterrupt();
643                 ++num_async_interrupts_sent;
644             }
645         }
646     }
647     else
648     {
649         // We don't have a valid pid to broadcast to, so broadcast to the target
650         // list's async broadcaster...
651         BroadcastEvent (Process::eBroadcastBitInterrupt, NULL);
652     }
653 
654     return num_async_interrupts_sent;
655 }
656 
657 uint32_t
658 TargetList::SignalIfRunning (lldb::pid_t pid, int signo)
659 {
660     uint32_t num_signals_sent = 0;
661     Process *process = NULL;
662     if (pid == LLDB_INVALID_PROCESS_ID)
663     {
664         // Signal all processes with signal
665         Mutex::Locker locker(m_target_list_mutex);
666         collection::iterator pos, end = m_target_list.end();
667         for (pos = m_target_list.begin(); pos != end; ++pos)
668         {
669             process = (*pos)->GetProcessSP().get();
670             if (process)
671             {
672                 if (process->IsAlive())
673                 {
674                     ++num_signals_sent;
675                     process->Signal (signo);
676                 }
677             }
678         }
679     }
680     else
681     {
682         // Signal a specific process with signal
683         TargetSP target_sp(FindTargetWithProcessID (pid));
684         if (target_sp.get())
685         {
686             process = target_sp->GetProcessSP().get();
687             if (process)
688             {
689                 if (process->IsAlive())
690                 {
691                     ++num_signals_sent;
692                     process->Signal (signo);
693                 }
694             }
695         }
696     }
697     return num_signals_sent;
698 }
699 
700 int
701 TargetList::GetNumTargets () const
702 {
703     Mutex::Locker locker (m_target_list_mutex);
704     return m_target_list.size();
705 }
706 
707 lldb::TargetSP
708 TargetList::GetTargetAtIndex (uint32_t idx) const
709 {
710     TargetSP target_sp;
711     Mutex::Locker locker (m_target_list_mutex);
712     if (idx < m_target_list.size())
713         target_sp = m_target_list[idx];
714     return target_sp;
715 }
716 
717 uint32_t
718 TargetList::GetIndexOfTarget (lldb::TargetSP target_sp) const
719 {
720     Mutex::Locker locker (m_target_list_mutex);
721     size_t num_targets = m_target_list.size();
722     for (size_t idx = 0; idx < num_targets; idx++)
723     {
724         if (target_sp == m_target_list[idx])
725             return idx;
726     }
727     return UINT32_MAX;
728 }
729 
730 uint32_t
731 TargetList::SetSelectedTarget (Target* target)
732 {
733     Mutex::Locker locker (m_target_list_mutex);
734     collection::const_iterator pos,
735         begin = m_target_list.begin(),
736         end = m_target_list.end();
737     for (pos = begin; pos != end; ++pos)
738     {
739         if (pos->get() == target)
740         {
741             m_selected_target_idx = std::distance (begin, pos);
742             return m_selected_target_idx;
743         }
744     }
745     m_selected_target_idx = 0;
746     return m_selected_target_idx;
747 }
748 
749 lldb::TargetSP
750 TargetList::GetSelectedTarget ()
751 {
752     Mutex::Locker locker (m_target_list_mutex);
753     if (m_selected_target_idx >= m_target_list.size())
754         m_selected_target_idx = 0;
755     return GetTargetAtIndex (m_selected_target_idx);
756 }
757