unwind-forcedunwind.c 4.6 KB

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  1. /* Copyright (C) 2003, 2005, 2006, 2009 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Jakub Jelinek <jakub@redhat.com>.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public License as
  6. published by the Free Software Foundation; either version 2.1 of the
  7. License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; see the file COPYING.LIB. If not,
  14. write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  15. Boston, MA 02111-1307, USA. */
  16. #include <dlfcn.h>
  17. #include <stdio.h>
  18. #include <unwind.h>
  19. #include <pthreadP.h>
  20. #include <sysdep.h>
  21. #include <libgcc_s.h>
  22. #define __libc_dlopen(x) dlopen(x, (RTLD_LOCAL | RTLD_LAZY))
  23. #define __libc_dlsym dlsym
  24. #define __libc_dlclose dlclose
  25. static void *libgcc_s_handle;
  26. static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
  27. static _Unwind_Reason_Code (*libgcc_s_personality)
  28. (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *,
  29. struct _Unwind_Context *);
  30. static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
  31. (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
  32. static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
  33. void
  34. __attribute_noinline__
  35. pthread_cancel_init (void)
  36. {
  37. void *resume;
  38. void *personality;
  39. void *forcedunwind;
  40. void *getcfa;
  41. void *handle;
  42. if (__builtin_expect (libgcc_s_handle != NULL, 1))
  43. {
  44. /* Force gcc to reload all values. */
  45. __asm__ volatile ("" ::: "memory");
  46. return;
  47. }
  48. handle = __libc_dlopen (LIBGCC_S_SO);
  49. if (handle == NULL
  50. || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
  51. || (personality = __libc_dlsym (handle, "__gcc_personality_v0")) == NULL
  52. || (forcedunwind = __libc_dlsym (handle, "_Unwind_ForcedUnwind"))
  53. == NULL
  54. || (getcfa = __libc_dlsym (handle, "_Unwind_GetCFA")) == NULL
  55. #ifdef ARCH_CANCEL_INIT
  56. || ARCH_CANCEL_INIT (handle)
  57. #endif
  58. )
  59. {
  60. printf (LIBGCC_S_SO " must be installed for pthread_cancel to work\n");
  61. abort();
  62. }
  63. PTR_MANGLE (resume);
  64. libgcc_s_resume = resume;
  65. PTR_MANGLE (personality);
  66. libgcc_s_personality = personality;
  67. PTR_MANGLE (forcedunwind);
  68. libgcc_s_forcedunwind = forcedunwind;
  69. PTR_MANGLE (getcfa);
  70. libgcc_s_getcfa = getcfa;
  71. /* Make sure libgcc_s_handle is written last. Otherwise,
  72. pthread_cancel_init might return early even when the pointer the
  73. caller is interested in is not initialized yet. */
  74. atomic_write_barrier ();
  75. libgcc_s_handle = handle;
  76. }
  77. void
  78. __libc_freeres_fn_section
  79. __unwind_freeres (void)
  80. {
  81. void *handle = libgcc_s_handle;
  82. if (handle != NULL)
  83. {
  84. libgcc_s_handle = NULL;
  85. __libc_dlclose (handle);
  86. }
  87. }
  88. void
  89. _Unwind_Resume (struct _Unwind_Exception *exc)
  90. {
  91. if (__builtin_expect (libgcc_s_handle == NULL, 0))
  92. pthread_cancel_init ();
  93. void (*resume) (struct _Unwind_Exception *exc) = libgcc_s_resume;
  94. PTR_DEMANGLE (resume);
  95. resume (exc);
  96. }
  97. _Unwind_Reason_Code
  98. __gcc_personality_v0 (int version, _Unwind_Action actions,
  99. _Unwind_Exception_Class exception_class,
  100. struct _Unwind_Exception *ue_header,
  101. struct _Unwind_Context *context)
  102. {
  103. if (__builtin_expect (libgcc_s_handle == NULL, 0))
  104. pthread_cancel_init ();
  105. _Unwind_Reason_Code (*personality)
  106. (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *,
  107. struct _Unwind_Context *) = libgcc_s_personality;
  108. PTR_DEMANGLE (personality);
  109. return personality (version, actions, exception_class, ue_header, context);
  110. }
  111. _Unwind_Reason_Code
  112. _Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
  113. void *stop_argument)
  114. {
  115. if (__builtin_expect (libgcc_s_handle == NULL, 0))
  116. pthread_cancel_init ();
  117. _Unwind_Reason_Code (*forcedunwind)
  118. (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *)
  119. = libgcc_s_forcedunwind;
  120. PTR_DEMANGLE (forcedunwind);
  121. return forcedunwind (exc, stop, stop_argument);
  122. }
  123. _Unwind_Word
  124. _Unwind_GetCFA (struct _Unwind_Context *context)
  125. {
  126. if (__builtin_expect (libgcc_s_handle == NULL, 0))
  127. pthread_cancel_init ();
  128. _Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa;
  129. PTR_DEMANGLE (getcfa);
  130. return getcfa (context);
  131. }