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Diffstat (limited to 'elf/ldsodefs.h')
| -rw-r--r-- | elf/ldsodefs.h | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/elf/ldsodefs.h b/elf/ldsodefs.h new file mode 100644 index 0000000..f6202ba --- /dev/null +++ b/elf/ldsodefs.h @@ -0,0 +1,385 @@ +/* Run-time dynamic linker data structures for loaded ELF shared objects. + Copyright (C) 1995, 1996, 1997, 1998 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#ifndef _LDSODEFS_H +#define _LDSODEFS_H 1 + +#include <features.h> + +#define __need_size_t +#define __need_NULL +#include <stddef.h> + +#include <elf.h> +#include <dlfcn.h> +#include <link.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) + +/* 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. */ + }; + + +/* 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 /* ldsodefs.h */ |