diff options
Diffstat (limited to 'elf/link.h')
| -rw-r--r-- | elf/link.h | 368 |
1 files changed, 12 insertions, 356 deletions
diff --git a/elf/link.h b/elf/link.h index 9b0f898b11..30efa0ed25 100644 --- a/elf/link.h +++ b/elf/link.h @@ -1,4 +1,5 @@ -/* Run-time dynamic linker data structures for loaded ELF shared objects. +/* Data structure for communication from the run-time dynamic linker for + loaded ELF shared objects. Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -21,20 +22,12 @@ #define _LINK_H 1 #include <features.h> - -#define __need_size_t -#define __need_NULL -#include <stddef.h> - #include <elf.h> #include <dlfcn.h> -__BEGIN_DECLS - /* 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(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 @@ -78,56 +71,24 @@ extern struct r_debug _r_debug; for (dyn = _DYNAMIC; dyn->d_tag != DT_NULL) if (dyn->d_tag == DT_DEBUG) r_debug = (struct r_debug) dyn->d_un.d_ptr; */ - extern ElfW(Dyn) _DYNAMIC[]; -/* For the version handling we need an array with only names and their - hash values. */ -struct r_found_version - { - const char *name; - ElfW(Word) hash; - - int hidden; - const char *filename; - }; - -/* We want to cache information about the searches for shared objects. */ - -enum r_dir_status { unknown, nonexisting, existing }; - -struct r_search_path_elem - { - const char *dirname; - - size_t dirnamelen; - enum r_dir_status dirstatus; - - size_t machdirnamelen; - enum r_dir_status machdirstatus; - - /* Strings saying where the definition came from. */ - const char *what; - const char *where; - /* This link is only used in the `all_dirs' member of `r_search_path'. */ - struct r_search_path_elem *next; - }; - - -/* A data structure for a simple single linked list of strings. */ -struct libname_list - { - const char *name; /* Name requested (before search). */ - struct libname_list *next; /* Link to next name for this object. */ - }; +/* 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; /* 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. */ + 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 { @@ -142,7 +103,7 @@ struct link_map /* All following members are internal to the dynamic linker. They may change without notice. */ - struct libname_list *l_libname; + 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_PROCNUM) are indexed by the tag minus DT_LOPROC. @@ -202,309 +163,4 @@ struct link_map ElfW(Half) *l_versyms; }; - -/* Test whether given NAME matches any of the names of the given object. */ -static __inline int -__attribute__ ((unused)) -_dl_name_match_p (const char *__name, struct link_map *__map) -{ - int __found = strcmp (__name, __map->l_name) == 0; - struct libname_list *__runp = __map->l_libname; - - while (! __found && __runp != NULL) - if (strcmp (__name, __runp->name) == 0) - __found = 1; - else - __runp = __runp->next; - - return __found; -} - -/* Function used as argument for `_dl_receive_error' function. The - arguments are the error code, error string, and the objname the - error occurred in. */ -typedef void (*receiver_fct) (int, const char *, const char *); - -/* Internal functions of the run-time dynamic linker. - These can be accessed if you link again the dynamic linker - as a shared library, as in `-lld' or `/lib/ld.so' explicitly; - but are not normally of interest to user programs. - - The `-ldl' library functions in <dlfcn.h> provide a simple - user interface to run-time dynamic linking. */ - - -/* Parameters passed to the dynamic linker. */ -extern char **_dl_argv; - -/* Cached value of `getpagesize ()'. */ -extern size_t _dl_pagesize; - -/* File descriptor referring to the zero-fill device. */ -extern int _dl_zerofd; - -/* Name of the shared object to be profiled (if any). */ -extern const char *_dl_profile; -/* Map of shared object to be profiled. */ -extern struct link_map *_dl_profile_map; - -/* If nonzero the appropriate debug information is printed. */ -extern int _dl_debug_libs; -extern int _dl_debug_impcalls; -extern int _dl_debug_bindings; -extern int _dl_debug_symbols; -extern int _dl_debug_versions; -extern int _dl_debug_reloc; -extern int _dl_debug_files; - -/* File deccriptor to write debug messages to. */ -extern int _dl_debug_fd; - -/* OS-dependent function to open the zero-fill device. */ -extern int _dl_sysdep_open_zero_fill (void); /* dl-sysdep.c */ - -/* OS-dependent function to write a message on the specified - descriptor FD. All arguments are `const char *'; args until a null - pointer are concatenated to form the message to print. */ -extern void _dl_sysdep_output (int fd, const char *string, ...); - -/* OS-dependent function to write a debug message on the specified - descriptor for this. All arguments are `const char *'; args until - a null pointer are concatenated to form the message to print. If - NEW_LINE is nonzero it is assumed that the message starts on a new - line.*/ -extern void _dl_debug_message (int new_line, const char *string, ...); - -/* OS-dependent function to write a message on the standard output. - All arguments are `const char *'; args until a null pointer - are concatenated to form the message to print. */ -#define _dl_sysdep_message(string, args...) \ - _dl_sysdep_output (STDOUT_FILENO, string, ##args) - -/* OS-dependent function to write a message on the standard error. - All arguments are `const char *'; args until a null pointer - are concatenated to form the message to print. */ -#define _dl_sysdep_error(string, args...) \ - _dl_sysdep_output (STDERR_FILENO, string, ##args) - -/* OS-dependent function to give a fatal error message and exit - when the dynamic linker fails before the program is fully linked. - All arguments are `const char *'; args until a null pointer - are concatenated to form the message to print. */ -#define _dl_sysdep_fatal(string, args...) \ - do \ - { \ - _dl_sysdep_output (STDERR_FILENO, string, ##args); \ - _exit (127); \ - } \ - while (1) - -/* Nonzero if the program should be "secure" (i.e. it's setuid or somesuch). - This tells the dynamic linker to ignore environment variables. */ -extern int _dl_secure; - -/* This function is called by all the internal dynamic linker functions - when they encounter an error. ERRCODE is either an `errno' code or - zero; OBJECT is the name of the problematical shared object, or null if - it is a general problem; ERRSTRING is a string describing the specific - problem. */ -extern void _dl_signal_error (int errcode, - const char *object, - const char *errstring); - -/* Call OPERATE, catching errors from `dl_signal_error'. If there is no - error, *ERRSTRING is set to null. If there is an error, *ERRSTRING is - set to a string constructed from the strings passed to _dl_signal_error, - and the error code passed is the return value. ERRSTRING if nonzero - points to a malloc'ed string which the caller has to free after use. - ARGS is passed as argument to OPERATE. */ -extern int _dl_catch_error (char **errstring, - void (*operate) (void *), - void *args); - -/* Call OPERATE, receiving errors from `dl_signal_error'. Unlike - `_dl_catch_error' the operation is resumed after the OPERATE - function returns. - ARGS is passed as argument to OPERATE. */ -extern void _dl_receive_error (receiver_fct fct, void (*operate) (void *), - void *args); - - -/* Helper function for <dlfcn.h> functions. Runs the OPERATE function via - _dl_catch_error. Returns zero for success, nonzero for failure; and - arranges for `dlerror' to return the error details. - ARGS is passed as argument to OPERATE. */ -extern int _dlerror_run (void (*operate) (void *), void *args); - - -/* Open the shared object NAME and map in its segments. - LOADER's DT_RPATH is used in searching for NAME. - If the object is already opened, returns its existing map. - For preloaded shared objects PRELOADED is set to a non-zero - value to allow additional security checks. */ -extern struct link_map *_dl_map_object (struct link_map *loader, - const char *name, int preloaded, - int type, int trace_mode); - -/* Call _dl_map_object on the dependencies of MAP, and set up - MAP->l_searchlist. PRELOADS points to a vector of NPRELOADS previously - loaded objects that will be inserted into MAP->l_searchlist after MAP - but before its dependencies. */ -extern void _dl_map_object_deps (struct link_map *map, - struct link_map **preloads, - unsigned int npreloads, int trace_mode); - -/* Cache the locations of MAP's hash table. */ -extern void _dl_setup_hash (struct link_map *map); - - -/* Open the shared object NAME, relocate it, and run its initializer if it - hasn't already been run. MODE is as for `dlopen' (see <dlfcn.h>). If - the object is already opened, returns its existing map. */ -extern struct link_map *_dl_open (const char *name, int mode); - -/* Close an object previously opened by _dl_open. */ -extern void _dl_close (struct link_map *map); - - -/* Search loaded objects' symbol tables for a definition of the symbol - referred to by UNDEF. *SYM is the symbol table entry containing the - reference; it is replaced with the defining symbol, and the base load - address of the defining object is returned. SYMBOL_SCOPE is a - null-terminated list of object scopes to search; each object's - l_searchlist (i.e. the segment of the dependency tree starting at that - object) is searched in turn. REFERENCE_NAME should name the object - containing the reference; it is used in error messages. - RELOC_TYPE is a machine-dependent reloc type, which is passed to - the `elf_machine_lookup_*_p' macros in dl-machine.h to affect which - symbols can be chosen. */ -extern ElfW(Addr) _dl_lookup_symbol (const char *undef, - const ElfW(Sym) **sym, - struct link_map *symbol_scope[], - const char *reference_name, - int reloc_type); - -/* Lookup versioned symbol. */ -extern ElfW(Addr) _dl_lookup_versioned_symbol (const char *undef, - const ElfW(Sym) **sym, - struct link_map *symbol_scope[], - const char *reference_name, - const struct r_found_version *version, - int reloc_type); - -/* For handling RTLD_NEXT we must be able to skip shared objects. */ -extern ElfW(Addr) _dl_lookup_symbol_skip (const char *undef, - const ElfW(Sym) **sym, - struct link_map *symbol_scope[], - const char *reference_name, - struct link_map *skip_this); - -/* For handling RTLD_NEXT with versioned symbols we must be able to - skip shared objects. */ -extern ElfW(Addr) _dl_lookup_versioned_symbol_skip (const char *undef, - const ElfW(Sym) **sym, - struct link_map *symbol_scope[], - const char *reference_name, - const struct r_found_version *version, - struct link_map *skip_this); - -/* Locate shared object containing the given address. */ -extern int _dl_addr (const void *address, Dl_info *info); - -/* Look up symbol NAME in MAP's scope and return its run-time address. */ -extern ElfW(Addr) _dl_symbol_value (struct link_map *map, const char *name); - - -/* Structure describing the dynamic linker itself. */ -extern struct link_map _dl_rtld_map; - -/* The list of objects currently loaded is the third element of the - `_dl_default_scope' array, and the fourth element is always null. - This leaves two slots before it that are used when resolving - DT_SYMBOLIC objects' references one after it for normal references - (see below). */ -#define _dl_loaded (_dl_default_scope[2]) -extern struct link_map *_dl_default_scope[5]; - -/* Null-terminated list of objects in the dynamic `global scope'. The - list starts at [2]; i.e. &_dl_global_scope[2] is the argument - passed to _dl_lookup_symbol to search the global scope. To search - a specific object and its dependencies in preference to the global - scope, fill in the [1] slot and pass its address; for two specific - object scopes, fill [0] and [1]. The list is double-terminated; to - search the global scope and then a specific object and its - dependencies, set *_dl_global_scope_end. This variable initially - points to _dl_default_scope, and _dl_loaded is always kept in [2] - of this list. A new list is malloc'd when new objects are loaded - with RTLD_GLOBAL. */ -extern struct link_map **_dl_global_scope, **_dl_global_scope_end; -extern size_t _dl_global_scope_alloc; /* Number of slots malloc'd. */ - -/* Hack _dl_global_scope[0] and [1] as necessary, and return a pointer into - _dl_global_scope that should be passed to _dl_lookup_symbol for symbol - references made in the object MAP's relocations. */ -extern struct link_map **_dl_object_relocation_scope (struct link_map *map); - - -/* Allocate a `struct link_map' for a new object being loaded, - and enter it into the _dl_loaded list. */ -extern struct link_map *_dl_new_object (char *realname, const char *libname, - int type); - -/* Relocate the given object (if it hasn't already been). - SCOPE is passed to _dl_lookup_symbol in symbol lookups. - If LAZY is nonzero, don't relocate its PLT. */ -extern void _dl_relocate_object (struct link_map *map, - struct link_map *scope[], - int lazy); - -/* Check the version dependencies of all objects available through - MAP. If VERBOSE print some more diagnostics. */ -extern int _dl_check_all_versions (struct link_map *map, int verbose); - -/* Check the version dependencies for MAP. If VERBOSE print some more - diagnostics. */ -extern int _dl_check_map_versions (struct link_map *map, int verbose); - -/* Return the address of the next initializer function for MAP or one of - its dependencies that has not yet been run. When there are no more - initializers to be run, this returns zero. The functions are returned - in the order they should be called. */ -extern ElfW(Addr) _dl_init_next (struct link_map *map); - -/* Call the finalizer functions of all shared objects whose - initializer functions have completed. */ -extern void _dl_fini (void); - -/* The dynamic linker calls this function before and having changing - any shared object mappings. The `r_state' member of `struct r_debug' - says what change is taking place. This function's address is - the value of the `r_brk' member. */ -extern void _dl_debug_state (void); - -/* Initialize `struct r_debug' if it has not already been done. The - argument is the run-time load address of the dynamic linker, to be put - in the `r_ldbase' member. Returns the address of the structure. */ -extern struct r_debug *_dl_debug_initialize (ElfW(Addr) ldbase); - -/* Initialize the basic data structure for the search paths. */ -extern void _dl_init_paths (const char *library_path); - -/* Gather the information needed to install the profiling tables and start - the timers. */ -extern void _dl_start_profile (struct link_map *map, const char *output_dir); - -/* The actual functions used to keep book on the calls. */ -extern void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc); - - -/* Show the members of the auxiliary array passed up from the kernel. */ -extern void _dl_show_auxv (void); - -/* Return all environment variables starting with `LD_', one after the - other. */ -extern char *_dl_next_ld_env_entry (char ***position); - -__END_DECLS - #endif /* link.h */ |