1 //===-- sanitizer_libignore.h -----------------------------------*- 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 // LibIgnore allows to ignore all interceptors called from a particular set
11 // of dynamic libraries. LibIgnore can be initialized with several templates
12 // of names of libraries to be ignored. It finds code ranges for the libraries;
13 // and checks whether the provided PC value belongs to the code ranges.
14 //
15 //===----------------------------------------------------------------------===//
16 
17 #ifndef SANITIZER_LIBIGNORE_H
18 #define SANITIZER_LIBIGNORE_H
19 
20 #include "sanitizer_internal_defs.h"
21 #include "sanitizer_common.h"
22 #include "sanitizer_atomic.h"
23 #include "sanitizer_mutex.h"
24 
25 namespace __sanitizer {
26 
27 class LibIgnore {
28  public:
29   explicit LibIgnore(LinkerInitialized);
30 
31   // Must be called during initialization.
32   void AddIgnoredLibrary(const char *name_templ);
33 
34   // Must be called after a new dynamic library is loaded.
35   void OnLibraryLoaded(const char *name);
36 
37   // Must be called after a dynamic library is unloaded.
38   void OnLibraryUnloaded();
39 
40   // Checks whether the provided PC belongs to one of the ignored libraries.
41   bool IsIgnored(uptr pc) const;
42 
43  private:
44   struct Lib {
45     char *templ;
46     char *name;
47     char *real_name;  // target of symlink
48     bool loaded;
49   };
50 
51   struct LibCodeRange {
52     uptr begin;
53     uptr end;
54   };
55 
56   static const uptr kMaxLibs = 128;
57 
58   // Hot part:
59   atomic_uintptr_t loaded_count_;
60   LibCodeRange code_ranges_[kMaxLibs];
61 
62   // Cold part:
63   BlockingMutex mutex_;
64   uptr count_;
65   Lib libs_[kMaxLibs];
66 
67   // Disallow copying of LibIgnore objects.
68   LibIgnore(const LibIgnore&);  // not implemented
69   void operator = (const LibIgnore&);  // not implemented
70 };
71 
IsIgnored(uptr pc)72 inline bool LibIgnore::IsIgnored(uptr pc) const {
73   const uptr n = atomic_load(&loaded_count_, memory_order_acquire);
74   for (uptr i = 0; i < n; i++) {
75     if (pc >= code_ranges_[i].begin && pc < code_ranges_[i].end)
76       return true;
77   }
78   return false;
79 }
80 
81 }  // namespace __sanitizer
82 
83 #endif  // SANITIZER_LIBIGNORE_H
84