| /* Data structure for communication from the run-time dynamic linker for |
| loaded ELF shared objects. |
| Copyright (C) 1995-2021 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <https://www.gnu.org/licenses/>. */ |
| |
| #ifndef _LINK_H |
| #define _LINK_H 1 |
| |
| #include <features.h> |
| #include <elf.h> |
| #include <dlfcn.h> |
| #include <sys/types.h> |
| |
| /* We use this macro to refer to ELF types independent of the native wordsize. |
| `ElfW(TYPE)' is used in place of `Elf32_TYPE' or `Elf64_TYPE'. */ |
| #define ElfW(type) _ElfW (Elf, __ELF_NATIVE_CLASS, type) |
| #define _ElfW(e,w,t) _ElfW_1 (e, w, _##t) |
| #define _ElfW_1(e,w,t) e##w##t |
| |
| #include <bits/elfclass.h> /* Defines __ELF_NATIVE_CLASS. */ |
| #include <bits/link.h> |
| |
| /* Rendezvous structure used by the run-time dynamic linker to communicate |
| details of shared object loading to the debugger. If the executable's |
| dynamic section has a DT_DEBUG element, the run-time linker sets that |
| element's value to the address where this structure can be found. */ |
| |
| struct r_debug |
| { |
| int r_version; /* Version number for this protocol. */ |
| |
| struct link_map *r_map; /* Head of the chain of loaded objects. */ |
| |
| /* This is the address of a function internal to the run-time linker, |
| that will always be called when the linker begins to map in a |
| library or unmap it, and again when the mapping change is complete. |
| The debugger can set a breakpoint at this address if it wants to |
| notice shared object mapping changes. */ |
| ElfW(Addr) r_brk; |
| enum |
| { |
| /* This state value describes the mapping change taking place when |
| the `r_brk' address is called. */ |
| RT_CONSISTENT, /* Mapping change is complete. */ |
| RT_ADD, /* Beginning to add a new object. */ |
| RT_DELETE /* Beginning to remove an object mapping. */ |
| } r_state; |
| |
| ElfW(Addr) r_ldbase; /* Base address the linker is loaded at. */ |
| }; |
| |
| /* This is the instance of that structure used by the dynamic linker. */ |
| extern struct r_debug _r_debug; |
| |
| /* This symbol refers to the "dynamic structure" in the `.dynamic' section |
| of whatever module refers to `_DYNAMIC'. So, to find its own |
| `struct r_debug', a program could do: |
| for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL; ++dyn) |
| if (dyn->d_tag == DT_DEBUG) |
| r_debug = (struct r_debug *) dyn->d_un.d_ptr; |
| */ |
| extern ElfW(Dyn) _DYNAMIC[]; |
| |
| /* Structure describing a loaded shared object. The `l_next' and `l_prev' |
| members form a chain of all the shared objects loaded at startup. |
| |
| These data structures exist in space used by the run-time dynamic linker; |
| modifying them may have disastrous results. */ |
| |
| struct link_map |
| { |
| /* These first few members are part of the protocol with the debugger. |
| This is the same format used in SVR4. */ |
| |
| ElfW(Addr) l_addr; /* Difference between the address in the ELF |
| file and the addresses in memory. */ |
| char *l_name; /* Absolute file name object was found in. */ |
| ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */ |
| struct link_map *l_next, *l_prev; /* Chain of loaded objects. */ |
| }; |
| |
| #ifdef __USE_GNU |
| |
| /* Version numbers for la_version handshake interface. */ |
| #define LAV_CURRENT 1 |
| |
| /* Activity types signaled through la_activity. */ |
| enum |
| { |
| LA_ACT_CONSISTENT, /* Link map consistent again. */ |
| LA_ACT_ADD, /* New object will be added. */ |
| LA_ACT_DELETE /* Objects will be removed. */ |
| }; |
| |
| /* Values representing origin of name for dynamic loading. */ |
| enum |
| { |
| LA_SER_ORIG = 0x01, /* Original name. */ |
| LA_SER_LIBPATH = 0x02, /* Directory from LD_LIBRARY_PATH. */ |
| LA_SER_RUNPATH = 0x04, /* Directory from RPATH/RUNPATH. */ |
| LA_SER_CONFIG = 0x08, /* Found through ldconfig. */ |
| LA_SER_DEFAULT = 0x40, /* Default directory. */ |
| LA_SER_SECURE = 0x80 /* Unused. */ |
| }; |
| |
| /* Values for la_objopen return value. */ |
| enum |
| { |
| LA_FLG_BINDTO = 0x01, /* Audit symbols bound to this object. */ |
| LA_FLG_BINDFROM = 0x02 /* Audit symbols bound from this object. */ |
| }; |
| |
| /* Values for la_symbind flags parameter. */ |
| enum |
| { |
| LA_SYMB_NOPLTENTER = 0x01, /* la_pltenter will not be called. */ |
| LA_SYMB_NOPLTEXIT = 0x02, /* la_pltexit will not be called. */ |
| LA_SYMB_STRUCTCALL = 0x04, /* Return value is a structure. */ |
| LA_SYMB_DLSYM = 0x08, /* Binding due to dlsym call. */ |
| LA_SYMB_ALTVALUE = 0x10 /* Value has been changed by a previous |
| la_symbind call. */ |
| }; |
| |
| struct dl_phdr_info |
| { |
| ElfW(Addr) dlpi_addr; |
| const char *dlpi_name; |
| const ElfW(Phdr) *dlpi_phdr; |
| ElfW(Half) dlpi_phnum; |
| |
| /* Note: Following members were introduced after the first |
| version of this structure was available. Check the SIZE |
| argument passed to the dl_iterate_phdr callback to determine |
| whether or not each later member is available. */ |
| |
| /* Incremented when a new object may have been added. */ |
| __extension__ unsigned long long int dlpi_adds; |
| /* Incremented when an object may have been removed. */ |
| __extension__ unsigned long long int dlpi_subs; |
| |
| /* If there is a PT_TLS segment, its module ID as used in |
| TLS relocations, else zero. */ |
| size_t dlpi_tls_modid; |
| |
| /* The address of the calling thread's instance of this module's |
| PT_TLS segment, if it has one and it has been allocated |
| in the calling thread, otherwise a null pointer. */ |
| void *dlpi_tls_data; |
| }; |
| |
| __BEGIN_DECLS |
| |
| extern int dl_iterate_phdr (int (*__callback) (struct dl_phdr_info *, |
| size_t, void *), |
| void *__data); |
| |
| |
| /* Prototypes for the ld.so auditing interfaces. These are not |
| defined anywhere in ld.so but instead have to be provided by the |
| auditing DSO. */ |
| extern unsigned int la_version (unsigned int __version); |
| extern void la_activity (uintptr_t *__cookie, unsigned int __flag); |
| extern char *la_objsearch (const char *__name, uintptr_t *__cookie, |
| unsigned int __flag); |
| extern unsigned int la_objopen (struct link_map *__map, Lmid_t __lmid, |
| uintptr_t *__cookie); |
| extern void la_preinit (uintptr_t *__cookie); |
| extern uintptr_t la_symbind32 (Elf32_Sym *__sym, unsigned int __ndx, |
| uintptr_t *__refcook, uintptr_t *__defcook, |
| unsigned int *__flags, const char *__symname); |
| extern uintptr_t la_symbind64 (Elf64_Sym *__sym, unsigned int __ndx, |
| uintptr_t *__refcook, uintptr_t *__defcook, |
| unsigned int *__flags, const char *__symname); |
| extern unsigned int la_objclose (uintptr_t *__cookie); |
| |
| __END_DECLS |
| |
| #endif |
| |
| #endif /* link.h */ |