| [2] | 1 | /* Data structure for communication from the run-time dynamic linker for |
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| 2 | loaded ELF shared objects. |
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| 3 | Copyright (C) 1995-1999, 2000, 2001 Free Software Foundation, Inc. |
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| 4 | This file is part of the GNU C Library. |
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| 5 | |
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| 6 | The GNU C Library is free software; you can redistribute it and/or |
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| 7 | modify it under the terms of the GNU Lesser General Public |
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| 8 | License as published by the Free Software Foundation; either |
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| 9 | version 2.1 of the License, or (at your option) any later version. |
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| 10 | |
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| 11 | The GNU C Library is distributed in the hope that it will be useful, |
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 14 | Lesser General Public License for more details. |
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| 15 | |
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| 16 | You should have received a copy of the GNU Lesser General Public |
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| 17 | License along with the GNU C Library; if not, write to the Free |
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| 18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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| 19 | 02111-1307 USA. */ |
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| 20 | |
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| 21 | #ifndef _LINK_H |
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| 22 | #define _LINK_H 1 |
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| 23 | |
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| 24 | #include <features.h> |
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| 25 | #include <elf.h> |
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| 26 | #include <dlfcn.h> |
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| 27 | #include <sys/types.h> |
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| 28 | |
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| 29 | /* We use this macro to refer to ELF types independent of the native wordsize. |
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| 30 | `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */ |
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| 31 | #define ElfW(type) _ElfW (Elf, __ELF_NATIVE_CLASS, type) |
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| 32 | #define _ElfW(e,w,t) _ElfW_1 (e, w, _##t) |
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| 33 | #define _ElfW_1(e,w,t) e##w##t |
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| 34 | |
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| 35 | #include <bits/elfclass.h> /* Defines __ELF_NATIVE_CLASS. */ |
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| 36 | |
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| 37 | /* Rendezvous structure used by the run-time dynamic linker to communicate |
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| 38 | details of shared object loading to the debugger. If the executable's |
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| 39 | dynamic section has a DT_DEBUG element, the run-time linker sets that |
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| 40 | element's value to the address where this structure can be found. */ |
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| 41 | |
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| 42 | struct r_debug |
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| 43 | { |
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| 44 | int r_version; /* Version number for this protocol. */ |
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| 45 | |
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| 46 | struct link_map *r_map; /* Head of the chain of loaded objects. */ |
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| 47 | |
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| 48 | /* This is the address of a function internal to the run-time linker, |
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| 49 | that will always be called when the linker begins to map in a |
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| 50 | library or unmap it, and again when the mapping change is complete. |
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| 51 | The debugger can set a breakpoint at this address if it wants to |
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| 52 | notice shared object mapping changes. */ |
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| 53 | ElfW(Addr) r_brk; |
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| 54 | enum |
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| 55 | { |
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| 56 | /* This state value describes the mapping change taking place when |
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| 57 | the `r_brk' address is called. */ |
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| 58 | RT_CONSISTENT, /* Mapping change is complete. */ |
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| 59 | RT_ADD, /* Beginning to add a new object. */ |
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| 60 | RT_DELETE /* Beginning to remove an object mapping. */ |
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| 61 | } r_state; |
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| 62 | |
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| 63 | ElfW(Addr) r_ldbase; /* Base address the linker is loaded at. */ |
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| 64 | }; |
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| 65 | |
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| 66 | /* This is the instance of that structure used by the dynamic linker. */ |
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| 67 | extern struct r_debug _r_debug; |
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| 68 | |
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| 69 | /* This symbol refers to the "dynamic structure" in the `.dynamic' section |
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| 70 | of whatever module refers to `_DYNAMIC'. So, to find its own |
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| 71 | `struct r_debug', a program could do: |
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| 72 | for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn) |
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| 73 | if (dyn->d_tag == DT_DEBUG) |
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| 74 | r_debug = (struct r_debug *) dyn->d_un.d_ptr; |
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| 75 | */ |
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| 76 | extern ElfW(Dyn) _DYNAMIC[]; |
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| 77 | |
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| 78 | /* Structure describing a loaded shared object. The `l_next' and `l_prev' |
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| 79 | members form a chain of all the shared objects loaded at startup. |
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| 80 | |
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| 81 | These data structures exist in space used by the run-time dynamic linker; |
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| 82 | modifying them may have disastrous results. */ |
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| 83 | |
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| 84 | struct link_map |
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| 85 | { |
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| 86 | /* These first few members are part of the protocol with the debugger. |
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| 87 | This is the same format used in SVR4. */ |
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| 88 | |
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| 89 | ElfW(Addr) l_addr; /* Base address shared object is loaded at. */ |
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| 90 | char *l_name; /* Absolute file name object was found in. */ |
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| 91 | ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */ |
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| 92 | struct link_map *l_next, *l_prev; /* Chain of loaded objects. */ |
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| 93 | }; |
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| 94 | |
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| 95 | #ifdef __USE_GNU |
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| 96 | |
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| 97 | struct dl_phdr_info |
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| 98 | { |
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| 99 | ElfW(Addr) dlpi_addr; |
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| 100 | const char *dlpi_name; |
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| 101 | const ElfW(Phdr) *dlpi_phdr; |
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| 102 | ElfW(Half) dlpi_phnum; |
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| 103 | }; |
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| 104 | |
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| 105 | __BEGIN_DECLS |
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| 106 | |
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| 107 | extern int dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info, |
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| 108 | size_t size, void *data), |
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| 109 | void *data) __THROW; |
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| 110 | |
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| 111 | __END_DECLS |
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| 112 | |
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| 113 | #endif |
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| 114 | |
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| 115 | #endif /* link.h */ |
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