include/lttng/ust-dlfcn.h

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * dlfcn.h compatibility layer.
   7  */
   8
   9 #ifndef _LTTNG_UST_DLFCN_H
  10 #define _LTTNG_UST_DLFCN_H
  11
  12 #ifdef _DLFCN_H
  13 #error "Please include lttng/ust-dlfcn.h before dlfcn.h."
  14 #endif /* _DLFCN_H */
  15
  16 #ifdef __GLIBC__
  17 /*
  18  * glibc declares dlsym() and dlerror() with __attribute__((leaf)) (see
  19  * THROW annotation). Unfortunately, this is not in sync with reality,
  20  * as those functions call the memory allocator. Work-around this glibc
  21  * bug by declaring our own symbols.
  22  *
  23  * There has been a similar issue for dlopen() and dlclose(), as
  24  * constructors and destructors are called from these functions, so they
  25  * are clearly non-leaf. Work-around the issue for those too for older
  26  * glibc where these have not been fixed.
  27  */
  28 #define dlopen glibc_dlopen_proto_lies_about_leafness
  29 #define dlclose glibc_dlclose_proto_lies_about_leafness
  30 #define dlsym glibc_dlsym_proto_lies_about_leafness
  31 #define dlerror glibc_dlerror_proto_lies_about_leafness
  32 #define dlmopen glibc_dlmopen_proto_lies_about_leafness
  33 #define dlvsym glibc_dlvsym_proto_lies_about_leafness
  34 #include <dlfcn.h>
  35 #undef dlvsym
  36 #undef dlmopen
  37 #undef dlerror
  38 #undef dlsym
  39 #undef dlclose
  40 #undef dlopen
  41
  42 extern void *dlopen(__const char *__file, int __mode);
  43 extern int dlclose(void *__handle) __nonnull ((1));
  44 extern void *dlsym(void *__restrict __handle,
  45                 __const char *__restrict __name) __nonnull ((2));
  46 extern char *dlerror(void);
  47 #ifdef __USE_GNU
  48 extern void *dlmopen(Lmid_t __nsid, const char *__file, int __mode);
  49 extern void *dlvsym(void *__restrict __handle,
  50                 __const char *__restrict __name,
  51                 __const char *__restrict __version);
  52 #endif
  53 #else
  54 #include <dlfcn.h>
  55 #endif /* __GLIBC__ */
  56
  57 #endif /* _LTTNG_UST_DLFCN_H */