/* $NetBSD: rtld.h,v 1.144.2.2 2023/08/01 17:03:53 martin Exp $ */ /* * Copyright 1996 John D. Polstra. * Copyright 1996 Matt Thomas * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by John Polstra. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef RTLD_H #define RTLD_H #include #include #include #include #include #include #include #include #include #include "rtldenv.h" #include "link.h" #if defined(_RTLD_SOURCE) #if defined(__ARM_EABI__) && !defined(__ARM_DWARF_EH__) #include "unwind.h" #endif #ifndef RTLD_DEFAULT_LIBRARY_PATH #define RTLD_DEFAULT_LIBRARY_PATH "/usr/lib" #endif #define _PATH_LD_HINTS "/etc/ld.so.conf" extern size_t _rtld_pagesz; #define round_down(x) ((x) & ~(_rtld_pagesz - 1)) #define round_up(x) round_down((x) + _rtld_pagesz - 1) #define NEW(type) ((type *) xmalloc(sizeof(type))) #define CNEW(type) ((type *) xcalloc(sizeof(type))) /* * Fill in a DoneList with an allocation large enough to hold all of * the currently-loaded objects. Keep this in a macro since it calls * alloca and we want that to occur within the scope of the caller. */ #define _rtld_donelist_init(dlp) \ ((dlp)->num_alloc = _rtld_objcount, \ (dlp)->objs = alloca((dlp)->num_alloc * sizeof((dlp)->objs[0])), \ assert((dlp)->objs != NULL), \ (dlp)->num_used = 0) typedef struct Struct_Elf_Hash { unsigned long sysv; unsigned long gnu; } Elf_Hash; #endif /* _RTLD_SOURCE */ /* * C++ has mandated the use of the following keywords for its new boolean * type. We might as well follow their lead. */ struct Struct_Obj_Entry; typedef struct Struct_Objlist_Entry { SIMPLEQ_ENTRY(Struct_Objlist_Entry) link; struct Struct_Obj_Entry *obj; } Objlist_Entry; typedef SIMPLEQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; typedef struct Struct_Name_Entry { SIMPLEQ_ENTRY(Struct_Name_Entry) link; char name[1]; } Name_Entry; typedef struct Struct_Needed_Entry { struct Struct_Needed_Entry *next; struct Struct_Obj_Entry *obj; unsigned long name; /* Offset of name in string table */ } Needed_Entry; typedef struct _rtld_search_path_t { struct _rtld_search_path_t *sp_next; const char *sp_path; size_t sp_pathlen; } Search_Path; typedef struct Struct_Ver_Entry { Elf_Word hash; u_int flags; const char *name; const char *file; } Ver_Entry; /* Ver_Entry.flags */ #define VER_INFO_HIDDEN 0x01 #define RTLD_MAX_ENTRY 10 #define RTLD_MAX_LIBRARY 4 #define RTLD_MAX_CTL 2 typedef struct _rtld_library_xform_t { struct _rtld_library_xform_t *next; char *name; const char *ctlname; struct { char *value; char *library[RTLD_MAX_LIBRARY]; } entry[RTLD_MAX_ENTRY]; } Library_Xform; /* * Shared object descriptor. * * Items marked with "(%)" are dynamically allocated, and must be freed * when the structure is destroyed. */ typedef void (*fptr_t)(void); typedef struct Struct_Obj_Entry { struct Struct_Obj_Entry *next; char *path; /* Pathname of underlying file (%) */ int refcount; int dl_refcount; /* Number of times loaded by dlopen */ /* These items are computed by map_object() or by digest_phdr(). */ caddr_t mapbase; /* Base address of mapped region */ size_t mapsize; /* Size of mapped region in bytes */ size_t textsize; /* Size of text segment in bytes */ Elf_Addr vaddrbase; /* Base address in shared object file */ caddr_t relocbase; /* Reloc const = mapbase - *vaddrbase */ Elf_Dyn *dynamic; /* Dynamic section */ caddr_t entry; /* Entry point */ const Elf_Phdr *phdr; /* Program header (may be xmalloc'ed) */ size_t phsize; /* Size of program header in bytes */ /* Items from the dynamic section. */ Elf_Addr *pltgot; /* PLTGOT table */ const Elf_Rel *rel; /* Relocation entries */ const Elf_Rel *rellim; /* Limit of Relocation entries */ const Elf_Rela *rela; /* Relocation entries */ const Elf_Rela *relalim; /* Limit of Relocation entries */ const Elf_Rel *pltrel; /* PLT relocation entries */ const Elf_Rel *pltrellim; /* Limit of PLT relocation entries */ const Elf_Rela *pltrela; /* PLT relocation entries */ const Elf_Rela *pltrelalim; /* Limit of PLT relocation entries */ const Elf_Sym *symtab; /* Symbol table */ const char *strtab; /* String table */ unsigned long strsize; /* Size in bytes of string table */ #if defined(__mips__) || defined(__riscv__) Elf_Word local_gotno; /* Number of local GOT entries */ Elf_Word symtabno; /* Number of dynamic symbols */ Elf_Word gotsym; /* First dynamic symbol in GOT */ #endif /* SysV Hash fields */ const Elf_Symindx *buckets; /* Hash table buckets array */ unsigned long unused1; /* Used to be nbuckets */ const Elf_Symindx *chains; /* Hash table chain array */ unsigned long nchains; /* Number of chains */ Search_Path *rpaths; /* Search path specified in object */ Needed_Entry *needed; /* Shared objects needed by this (%) */ fptr_t init; /* Initialization function to call */ fptr_t fini; /* Termination function to call */ u_int32_t mainprog:1, /* True if this is the main program */ rtld:1, /* True if this is the dynamic linker */ textrel:1, /* True if there are relocations to * text seg */ symbolic:1, /* True if generated with * "-Bsymbolic" */ printed:1, /* True if ldd has printed it */ isdynamic:1, /* True if this is a pure PIC object */ mainref:1, /* True if on _rtld_list_main */ globalref:1, /* True if on _rtld_list_global */ init_done:1, /* True if .init has been added */ init_called:1, /* True if .init function has been * called */ fini_called:1, /* True if .fini function has been * called */ z_now:1, /* True if object's symbols should be bound immediately */ z_nodelete:1, /* True if object should never be unloaded */ z_initfirst:1, /* True if object's .init/.fini take * priority over others */ z_noopen:1, /* True if object should never be dlopen'ed */ phdr_loaded:1, /* Phdr is loaded and doesn't need to * be freed. */ #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) tls_static:1, /* True if static TLS offset * has been allocated */ tls_dynamic:1, /* True if any non-static DTV entry * has been allocated */ #endif ref_nodel:1, /* Refcount increased to prevent dlclose */ sysv_hash:1, /* SysV Hash available */ gnu_hash:1; /* GNU Hash available */ struct link_map linkmap; /* for the debugger */ /* These items are computed by map_object() or by digest_phdr(). */ const char *interp; /* Pathname of the interpreter, if any */ Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ Objlist dagmembers; /* DAG has these members (%) */ dev_t dev; /* Object's filesystem's device */ ino_t ino; /* Object's inode number */ void *ehdr; /* SysV Hash fields */ uint32_t nbuckets; /* Number of buckets */ uint32_t nbuckets_m; /* Precomputed for fast remainder */ uint8_t nbuckets_s1; uint8_t nbuckets_s2; /* GNU Hash fields */ const uint32_t *buckets_gnu; /* Hash table buckets array */ uint32_t nbuckets_gnu; /* Number of GNU hash buckets */ uint32_t nbuckets_m_gnu; /* Precomputed for fast remainder */ uint8_t nbuckets_s1_gnu; uint8_t nbuckets_s2_gnu; const uint32_t *chains_gnu; /* Hash table chain array */ #define nchains_gnu nchains /* Number of symbols, shared with SysV Hash */ const Elf_Addr *bloom_gnu; uint32_t symndx_gnu; /* First accessible symbol on dynsym table */ uint32_t mask_bm_gnu; /* Bloom filter words - 1 (bitmask) */ uint32_t shift2_gnu; /* Bloom filter shift count */ size_t pathlen; /* Pathname length */ SIMPLEQ_HEAD(, Struct_Name_Entry) names; /* List of names for this * object we know about. */ #ifdef __powerpc__ #ifdef _LP64 Elf_Addr glink; /* global linkage */ #else Elf_Addr *gotptr; /* GOT table (secure-plt only) */ #endif #endif #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) /* Thread Local Storage support for this module */ size_t tlsindex; /* Index in DTV */ void *tlsinit; /* Base address of TLS init block */ size_t tlsinitsize; /* Size of TLS init block */ size_t tlssize; /* Size of TLS block */ size_t tlsoffset; /* Offset in the static TLS block */ size_t tlsalign; /* Needed alignment for static TLS */ #endif #ifdef GNU_RELRO /* relocation readonly */ void *relro_page; size_t relro_size; #endif /* symbol versioning */ const Elf_Verneed *verneed; /* Required versions. */ Elf_Word verneednum; /* Number of entries in verneed table */ const Elf_Verdef *verdef; /* Provided versions. */ Elf_Word verdefnum; /* Number of entries in verdef table */ const Elf_Versym *versyms; /* Symbol versions table */ Ver_Entry *vertab; /* Versions required/defined by this * object */ int vertabnum; /* Number of entries in vertab */ /* init_array/fini_array */ fptr_t *init_array; /* start of init array */ size_t init_arraysz; /* # of entries in it */ fptr_t *fini_array; /* start of fini array */ size_t fini_arraysz; /* # of entries in it */ /* IRELATIVE relocations */ size_t ifunc_remaining; #if \ defined(__aarch64__) || \ defined(__arm__) || \ defined(__i386__) || \ defined(__powerpc__) || \ defined(__sparc__) || \ defined(__x86_64__) #define IFUNC_NONPLT /* On SPARC, the PLT variant is called JMP_IREL and counted above. */ size_t ifunc_remaining_nonplt; #endif size_t cxa_refcount; /* For TLS destructors. */ #ifdef __ARM_EABI__ void *exidx_start; size_t exidx_sz; #endif } Obj_Entry; typedef struct Struct_DoneList { const Obj_Entry **objs; /* Array of object pointers */ unsigned int num_alloc; /* Allocated size of the array */ unsigned int num_used; /* Number of array slots used */ } DoneList; #if defined(_RTLD_SOURCE) extern struct r_debug _rtld_debug; extern Search_Path *_rtld_default_paths; extern Obj_Entry *_rtld_objlist; extern Obj_Entry **_rtld_objtail; extern u_int _rtld_objcount; extern u_int _rtld_objloads; extern const uintptr_t _rtld_compat_obj[]; extern Obj_Entry *_rtld_objmain; extern Obj_Entry _rtld_objself; extern Search_Path *_rtld_paths; extern Library_Xform *_rtld_xforms; extern bool _rtld_trust; extern Objlist _rtld_list_global; extern Objlist _rtld_list_main; extern Elf_Sym _rtld_sym_zero; extern u_int _rtld_objgen; #define RTLD_MODEMASK 0x3 /* Flags to be passed into _rtld_symlook_ family of functions. */ #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by dlsym. */ /* Flags for _rtld_load_object() and friends. */ #define _RTLD_GLOBAL 0x01 /* Add object to global DAG. */ #define _RTLD_MAIN 0x02 #define _RTLD_NOLOAD 0x04 /* dlopen() specified RTLD_NOLOAD. */ #define _RTLD_DLOPEN 0x08 /* Load_object() called from dlopen(). */ /* Preallocation for static TLS model */ #define RTLD_STATIC_TLS_RESERVATION 64 /* rtld.c */ __dso_public char *dlerror(void); __dso_public void *dlopen(const char *, int); __dso_public void *dlsym(void *, const char *); __dso_public int dlclose(void *); __dso_public int dladdr(const void *, Dl_info *); __dso_public int dlinfo(void *, int, void *); __dso_public int dl_iterate_phdr(int (*)(struct dl_phdr_info *, size_t, void *), void *); __dso_public void *_dlauxinfo(void) __pure; __dso_public void __dl_cxa_refcount(void *addr, ssize_t delta); __dso_public pid_t __locked_fork(int *); #if defined(__ARM_EABI__) && !defined(__ARM_DWARF_EH__) /* * This is used by libgcc to find the start and length of the exception table * associated with a PC. */ __dso_public _Unwind_Ptr __gnu_Unwind_Find_exidx(_Unwind_Ptr, int *); #endif /* These aren't exported */ void _rtld_error(const char *, ...) __printflike(1,2); void _rtld_die(void) __dead; void *_rtld_objmain_sym(const char *); __dso_public void _rtld_debug_state(void) __noinline; void _rtld_linkmap_add(Obj_Entry *); void _rtld_linkmap_delete(Obj_Entry *); void _rtld_objlist_push_head(Objlist *, Obj_Entry *); void _rtld_objlist_push_tail(Objlist *, Obj_Entry *); Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *); void _rtld_ref_dag(Obj_Entry *); void _rtld_shared_enter(void); void _rtld_shared_exit(void); void _rtld_exclusive_enter(sigset_t *); void _rtld_exclusive_exit(sigset_t *); int _rtld_relro(const Obj_Entry *, bool); /* expand.c */ size_t _rtld_expand_path(char *, size_t, const char *, const char *,\ const char *); /* headers.c */ void _rtld_digest_dynamic(const char *, Obj_Entry *); Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t); /* load.c */ Obj_Entry *_rtld_load_object(const char *, int); int _rtld_load_needed_objects(Obj_Entry *, int); int _rtld_preload(const char *); #define OBJ_ERR (Obj_Entry *)(-1) /* path.c */ void _rtld_add_paths(const char *, Search_Path **, const char *); void _rtld_process_hints(const char *, Search_Path **, Library_Xform **, const char *); int _rtld_sysctl(const char *, void *, size_t *); /* reloc.c */ int _rtld_do_copy_relocations(const Obj_Entry *); int _rtld_relocate_objects(Obj_Entry *, bool); int _rtld_relocate_nonplt_objects(Obj_Entry *); int _rtld_relocate_plt_lazy(Obj_Entry *); int _rtld_relocate_plt_objects(const Obj_Entry *); void _rtld_setup_pltgot(const Obj_Entry *); Elf_Addr _rtld_resolve_ifunc(const Obj_Entry *, const Elf_Sym *); Elf_Addr _rtld_resolve_ifunc2(const Obj_Entry *, Elf_Addr); void _rtld_call_ifunc(Obj_Entry *, sigset_t *, u_int); /* search.c */ Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int); /* symbol.c */ const Elf_Sym *_rtld_symlook_obj(const char *, Elf_Hash *, const Obj_Entry *, u_int, const Ver_Entry *); const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *, const Obj_Entry **, u_int); const Elf_Sym *_rtld_find_plt_symdef(unsigned long, const Obj_Entry *, const Obj_Entry **, bool); const Elf_Sym *_rtld_symlook_list(const char *, Elf_Hash *, const Objlist *, const Obj_Entry **, u_int, const Ver_Entry *, DoneList *); const Elf_Sym *_rtld_symlook_default(const char *, Elf_Hash *, const Obj_Entry *, const Obj_Entry **, u_int, const Ver_Entry *); const Elf_Sym *_rtld_symlook_needed(const char *, Elf_Hash *, const Needed_Entry *, const Obj_Entry **, u_int, const Ver_Entry *, DoneList *, DoneList *); /* symver.c */ void _rtld_object_add_name(Obj_Entry *, const char *); int _rtld_object_match_name(const Obj_Entry *, const char *); int _rtld_verify_object_versions(Obj_Entry *); static __inline const Ver_Entry * _rtld_fetch_ventry(const Obj_Entry *obj, unsigned long symnum) { Elf_Half vernum; if (obj->vertab) { vernum = VER_NDX(obj->versyms[symnum].vs_vers); if (vernum >= obj->vertabnum) { _rtld_error("%s: symbol %s has wrong verneed value %d", obj->path, &obj->strtab[symnum], vernum); } else if (obj->vertab[vernum].hash) { return &obj->vertab[vernum]; } } return NULL; } #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II) /* tls.c */ void *_rtld_tls_get_addr(void *, size_t, size_t); void _rtld_tls_initial_allocation(void); int _rtld_tls_offset_allocate(Obj_Entry *); void _rtld_tls_offset_free(Obj_Entry *); extern size_t _rtld_tls_dtv_generation; extern size_t _rtld_tls_max_index; __dso_public extern void *__tls_get_addr(void *); #ifdef __i386__ __dso_public extern void *___tls_get_addr(void *) __attribute__((__regparm__(1))); #endif #endif /* map_object.c */ struct stat; Obj_Entry *_rtld_map_object(const char *, int, const struct stat *); void _rtld_obj_free(Obj_Entry *); Obj_Entry *_rtld_obj_new(void); #ifdef RTLD_LOADER /* function descriptors */ #ifdef __HAVE_FUNCTION_DESCRIPTORS Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *, const Elf_Sym *, Elf_Addr); const void *_rtld_function_descriptor_function(const void *); Elf_Addr _rtld_call_function_addr(const Obj_Entry *, Elf_Addr); #else static inline Elf_Addr _rtld_call_function_addr(const Obj_Entry *obj, Elf_Addr addr) { return ((Elf_Addr(*)(void))addr)(); } #endif /* __HAVE_FUNCTION_DESCRIPTORS */ #endif /* RTLD_LOADER */ #endif /* _RTLD_SOURCE */ #endif /* RTLD_H */