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glibc-2.41
include/link.h
389 строк
14 KB
Paul Eggert
Update copyright dates with scripts/update-copyrights
01 янв 2025, 22:22
01 янв 2025, 22:22
2642002
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/* Data structure for communication from the run-time dynamic linker for loaded ELF shared objects. Copyright (C) 1995-2025 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 _PRIVATE_LINK_H #define _PRIVATE_LINK_H 1 #ifdef _LINK_H # error this should be impossible #endif # ifndef _ISOMAC /* Get most of the contents from the public header, but we define a different `struct link_map' type for private use. The la_objopen prototype uses the type, so we have to declare it separately. */ # define link_map link_map_public # define la_objopen la_objopen_wrongproto # endif #include <elf/link.h> # ifndef _ISOMAC #undef link_map #undef la_objopen struct link_map; extern unsigned int la_objopen (struct link_map *__map, Lmid_t __lmid, uintptr_t *__cookie); #include <stdint.h> #include <stddef.h> #include <linkmap.h> #include <dl-fileid.h> #include <dl-lookupcfg.h> #include <tls.h> #include <libc-lock.h> /* Some internal data structures of the dynamic linker used in the linker map. We only provide forward declarations. */ struct libname_list; struct r_found_version; struct r_search_path_elem; /* Forward declaration. */ struct link_map; /* Structure to describe a single list of scope elements. The lookup functions get passed an array of pointers to such structures. */ struct r_scope_elem { /* Array of maps for the scope. */ struct link_map **r_list; /* Number of entries in the scope. */ unsigned int r_nlist; }; /* Structure to record search path and allocation mechanism. */ struct r_search_path_struct { struct r_search_path_elem **dirs; int malloced; }; /* Search path information computed by _dl_init_paths. */ extern struct r_search_path_struct __rtld_search_dirs attribute_hidden; extern struct r_search_path_struct __rtld_env_path_list attribute_hidden; /* 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. This data structure might change in future, if necessary. User-level programs must avoid defining objects of this type. */ 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. */ /* All following members are internal to the dynamic linker. They may change without notice. */ /* This is an element which is only ever different from a pointer to the very same copy of this type for ld.so when it is used in more than one namespace. */ struct link_map *l_real; /* Number of the namespace this link map belongs to. */ Lmid_t l_ns; struct libname_list *l_libname; /* Indexed pointers to dynamic section. [0,DT_NUM) are indexed by the processor-independent tags. [DT_NUM,DT_NUM+DT_THISPROCNUM) are indexed by the tag minus DT_LOPROC. [DT_NUM+DT_THISPROCNUM,DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM) are indexed by DT_VERSIONTAGIDX(tagvalue). [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM, DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM) are indexed by DT_EXTRATAGIDX(tagvalue). [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM, DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM) are indexed by DT_VALTAGIDX(tagvalue) and [DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM, DT_NUM+DT_THISPROCNUM+DT_VERSIONTAGNUM+DT_EXTRANUM+DT_VALNUM+DT_ADDRNUM) are indexed by DT_ADDRTAGIDX(tagvalue), see <elf.h>. */ ElfW(Dyn) *l_info[DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM + DT_ADDRNUM]; const ElfW(Phdr) *l_phdr; /* Pointer to program header table in core. */ ElfW(Addr) l_entry; /* Entry point location. */ ElfW(Half) l_phnum; /* Number of program header entries. */ ElfW(Half) l_ldnum; /* Number of dynamic segment entries. */ /* Array of DT_NEEDED dependencies and their dependencies, in dependency order for symbol lookup (with and without duplicates). There is no entry before the dependencies have been loaded. */ struct r_scope_elem l_searchlist; /* We need a special searchlist to process objects marked with DT_SYMBOLIC. */ struct r_scope_elem l_symbolic_searchlist; /* Dependent object that first caused this object to be loaded. */ struct link_map *l_loader; /* Array with version names. */ struct r_found_version *l_versions; unsigned int l_nversions; /* Symbol hash table. */ Elf_Symndx l_nbuckets; Elf32_Word l_gnu_bitmask_idxbits; Elf32_Word l_gnu_shift; const ElfW(Addr) *l_gnu_bitmask; union { const Elf32_Word *l_gnu_buckets; const Elf_Symndx *l_chain; }; union { const Elf32_Word *l_gnu_chain_zero; const Elf_Symndx *l_buckets; }; unsigned int l_direct_opencount; /* Reference count for dlopen/dlclose. */ enum /* Where this object came from. */ { lt_executable, /* The main executable program. */ lt_library, /* Library needed by main executable. */ lt_loaded /* Extra run-time loaded shared object. */ } l_type:2; unsigned int l_dt_relr_ref:1; /* Nonzero if GLIBC_ABI_DT_RELR is referenced. */ unsigned int l_relocated:1; /* Nonzero if object's relocations done. */ unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */ unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */ unsigned int l_reserved:2; /* Reserved for internal use. */ unsigned int l_main_map:1; /* Nonzero for the map of the main program. */ unsigned int l_visited:1; /* Used internally for map dependency graph traversal. */ unsigned int l_map_used:1; /* These two bits are used during traversal */ unsigned int l_map_done:1; /* of maps in _dl_close_worker. */ unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed to by `l_phdr' is allocated. */ unsigned int l_soname_added:1; /* Nonzero if the SONAME is for sure in the l_libname list. */ unsigned int l_faked:1; /* Nonzero if this is a faked descriptor without associated file. */ unsigned int l_need_tls_init:1; /* Nonzero if GL(dl_init_static_tls) should be called on this link map when relocation finishes. */ unsigned int l_auditing:1; /* Nonzero if the DSO is used in auditing. */ unsigned int l_audit_any_plt:1; /* Nonzero if at least one audit module is interested in the PLT interception.*/ unsigned int l_removed:1; /* Nozero if the object cannot be used anymore since it is removed. */ unsigned int l_contiguous:1; /* Nonzero if inter-segment holes are mprotected or if no holes are present at all. */ unsigned int l_free_initfini:1; /* Nonzero if l_initfini can be freed, ie. not allocated with the dummy malloc in ld.so. */ unsigned int l_ld_readonly:1; /* Nonzero if dynamic section is readonly. */ unsigned int l_find_object_processed:1; /* Zero if _dl_find_object_update needs to process this lt_library map. */ unsigned int l_tls_in_slotinfo:1; /* TLS slotinfo updated in dlopen. */ /* NODELETE status of the map. Only valid for maps of type lt_loaded. Lazy binding sets l_nodelete_active directly, potentially from signal handlers. Initial loading of an DF_1_NODELETE object set l_nodelete_pending. Relocation may set l_nodelete_pending as well. l_nodelete_pending maps are promoted to l_nodelete_active status in the final stages of dlopen, prior to calling ELF constructors. dlclose only refuses to unload l_nodelete_active maps, the pending status is ignored. */ bool l_nodelete_active; bool l_nodelete_pending; #include <link_map.h> /* Collected information about own RPATH directories. */ struct r_search_path_struct l_rpath_dirs; /* Collected results of relocation while profiling. */ struct reloc_result { DL_FIXUP_VALUE_TYPE addr; struct link_map *bound; unsigned int boundndx; uint32_t enterexit; unsigned int flags; /* CONCURRENCY NOTE: This is used to guard the concurrent initialization of the relocation result across multiple threads. See the more detailed notes in elf/dl-runtime.c. */ unsigned int init; } *l_reloc_result; /* Pointer to the version information if available. */ ElfW(Versym) *l_versyms; /* String specifying the path where this object was found. */ const char *l_origin; /* Start and finish of memory map for this object. l_map_start need not be the same as l_addr. */ ElfW(Addr) l_map_start, l_map_end; /* Default array for 'l_scope'. */ struct r_scope_elem *l_scope_mem[4]; /* Size of array allocated for 'l_scope'. */ size_t l_scope_max; /* This is an array defining the lookup scope for this link map. There are initially at most three different scope lists. */ struct r_scope_elem **l_scope; /* A similar array, this time only with the local scope. This is used occasionally. */ struct r_scope_elem *l_local_scope[2]; /* This information is kept to check for sure whether a shared object is the same as one already loaded. */ struct r_file_id l_file_id; /* Collected information about own RUNPATH directories. */ struct r_search_path_struct l_runpath_dirs; /* List of object in order of the init and fini calls. */ struct link_map **l_initfini; /* List of the dependencies introduced through symbol binding. */ struct link_map_reldeps { unsigned int act; struct link_map *list[]; } *l_reldeps; unsigned int l_reldepsmax; /* Nonzero if the DSO is used. */ unsigned int l_used; /* Various flag words. */ ElfW(Word) l_feature_1; ElfW(Word) l_flags_1; ElfW(Word) l_flags; /* Temporarily used in `dl_close'. */ int l_idx; struct link_map_machine l_mach; struct { const ElfW(Sym) *sym; int type_class; struct link_map *value; const ElfW(Sym) *ret; } l_lookup_cache; /* Thread-local storage related info. */ /* Start of the initialization image. */ void *l_tls_initimage; /* Size of the initialization image. */ size_t l_tls_initimage_size; /* Size of the TLS block. */ size_t l_tls_blocksize; /* Alignment requirement of the TLS block. */ size_t l_tls_align; /* Offset of first byte module alignment. */ size_t l_tls_firstbyte_offset; #ifndef NO_TLS_OFFSET # define NO_TLS_OFFSET 0 #endif #ifndef FORCED_DYNAMIC_TLS_OFFSET # if NO_TLS_OFFSET == 0 # define FORCED_DYNAMIC_TLS_OFFSET -1 # elif NO_TLS_OFFSET == -1 # define FORCED_DYNAMIC_TLS_OFFSET -2 # else # error "FORCED_DYNAMIC_TLS_OFFSET is not defined" # endif #endif /* For objects present at startup time: offset in the static TLS block. */ ptrdiff_t l_tls_offset; /* Index of the module in the dtv array. */ size_t l_tls_modid; /* Number of thread_local objects constructed by this DSO. This is atomically accessed and modified and is not always protected by the load lock. See also: CONCURRENCY NOTES in cxa_thread_atexit_impl.c. */ size_t l_tls_dtor_count; /* Information used to change permission after the relocations are done. */ ElfW(Addr) l_relro_addr; size_t l_relro_size; unsigned long long int l_serial; }; #include <dl-relocate-ld.h> /* Information used by audit modules. For most link maps, this data immediate follows the link map in memory. For the dynamic linker, it is allocated separately. See link_map_audit_state in <ldsodefs.h>. */ struct auditstate { uintptr_t cookie; unsigned int bindflags; }; /* This is the hidden instance of struct r_debug_extended used by the dynamic linker. */ extern struct r_debug_extended _r_debug_extended attribute_hidden; #if __ELF_NATIVE_CLASS == 32 # define symbind symbind32 # define LA_SYMBIND "la_symbind32" #elif __ELF_NATIVE_CLASS == 64 # define symbind symbind64 # define LA_SYMBIND "la_symbind64" #else # error "__ELF_NATIVE_CLASS must be defined" #endif extern int __dl_iterate_phdr (int (*callback) (struct dl_phdr_info *info, size_t size, void *data), void *data); hidden_proto (__dl_iterate_phdr) /* We use this macro to refer to ELF macros independent of the native wordsize. `ELFW(R_TYPE)' is used in place of `ELF32_R_TYPE' or `ELF64_R_TYPE'. */ #define ELFW(type) _ElfW (ELF, __ELF_NATIVE_CLASS, type) # endif /* !_ISOMAC */ #endif /* include/link.h */