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Diffstat (limited to 'libexec/rtld-elf/rtld.h')
| -rw-r--r-- | libexec/rtld-elf/rtld.h | 443 |
1 files changed, 443 insertions, 0 deletions
diff --git a/libexec/rtld-elf/rtld.h b/libexec/rtld-elf/rtld.h new file mode 100644 index 000000000000..d4829b17cebb --- /dev/null +++ b/libexec/rtld-elf/rtld.h @@ -0,0 +1,443 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. + * 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. + * + * 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 1 + +#include <machine/elf.h> +#include <sys/types.h> +#include <sys/queue.h> + +#include <elf-hints.h> +#include <link.h> +#include <stdarg.h> +#include <stdbool.h> +#include <setjmp.h> +#include <stddef.h> + +#include "rtld_lock.h" +#include "rtld_machdep.h" + +#define NEW(type) ((type *) xmalloc(sizeof(type))) +#define CNEW(type) ((type *) xcalloc(1, sizeof(type))) + +extern size_t tls_last_offset; +extern size_t tls_last_size; +extern size_t tls_static_space; +extern Elf_Addr tls_dtv_generation; +extern int tls_max_index; +extern size_t ld_static_tls_extra; + +extern int npagesizes; +extern size_t *pagesizes; +extern size_t page_size; + +extern int main_argc; +extern char **main_argv; +extern char **environ; + +struct stat; +struct Struct_Obj_Entry; + +/* Lists of shared objects */ +typedef struct Struct_Objlist_Entry { + STAILQ_ENTRY(Struct_Objlist_Entry) link; + struct Struct_Obj_Entry *obj; +} Objlist_Entry; + +typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; + +/* Types of init and fini functions */ +typedef void (*InitFunc)(void); +typedef void (*InitArrFunc)(int, char **, char **); + +/* Lists of shared object dependencies */ +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 Struct_Name_Entry { + STAILQ_ENTRY(Struct_Name_Entry) link; + char name[1]; +} Name_Entry; + +/* Lock object */ +typedef struct Struct_LockInfo { + void *context; /* Client context for creating locks */ + void *thelock; /* The one big lock */ + /* Debugging aids. */ + volatile int rcount; /* Number of readers holding lock */ + volatile int wcount; /* Number of writers holding lock */ + /* Methods */ + void *(*lock_create)(void *context); + void (*rlock_acquire)(void *lock); + void (*wlock_acquire)(void *lock); + void (*rlock_release)(void *lock); + void (*wlock_release)(void *lock); + void (*lock_destroy)(void *lock); + void (*context_destroy)(void *context); +} LockInfo; + +typedef struct Struct_Ver_Entry { + Elf_Word hash; + unsigned int flags; + const char *name; + const char *file; +} Ver_Entry; + +typedef struct Struct_Sym_Match_Result { + const Elf_Sym *sym_out; + const Elf_Sym *vsymp; + int vcount; +} Sym_Match_Result; + +#define VER_INFO_HIDDEN 0x01 + +/* + * Shared object descriptor. + * + * Items marked with "(%)" are dynamically allocated, and must be freed + * when the structure is destroyed. + * + * CAUTION: It appears that the JDK port peeks into these structures. + * It looks at "next" and "mapbase" at least. Don't add new members + * near the front, until this can be straightened out. + */ +typedef struct Struct_Obj_Entry { + /* + * These two items have to be set right for compatibility with the + * original ElfKit crt1.o. + */ + Elf_Size magic; /* Magic number (sanity check) */ + Elf_Size version; /* Version number of struct format */ + + TAILQ_ENTRY(Struct_Obj_Entry) next; + char *path; /* Pathname of underlying file (%) */ + char *origin_path; /* Directory path of origin file */ + int refcount; /* DAG references */ + int holdcount; /* Count of transient references */ + 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 */ + Elf_Addr vaddrbase; /* Base address in shared object file */ + caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ + const Elf_Dyn *dynamic; /* Dynamic section */ + caddr_t entry; /* Entry point */ + const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ + size_t phsize; /* Size of program header in bytes */ + const char *interp; /* Pathname of the interpreter, if any */ + Elf_Word stack_flags; + + /* TLS information */ + int tlsindex; /* Index in DTV for this module */ + void *tlsinit; /* Base address of TLS init block */ + size_t tlsinitsize; /* Size of TLS init block for this module */ + size_t tlssize; /* Size of TLS block for this module */ + size_t tlsoffset; /* Offset of static TLS block for this module */ + size_t tlsalign; /* Alignment of static TLS block */ + size_t tlspoffset; /* p_offset of the static TLS block */ + + /* Items from the dynamic section. */ + Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ + const Elf_Rel *rel; /* Relocation entries */ + unsigned long relsize; /* Size in bytes of relocation info */ + const Elf_Rela *rela; /* Relocation entries with addend */ + unsigned long relasize; /* Size in bytes of addend relocation info */ + const Elf_Relr *relr; /* RELR relocation entries */ + unsigned long relrsize; /* Size in bytes of RELR relocations */ + const Elf_Rel *pltrel; /* PLT relocation entries */ + unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ + const Elf_Rela *pltrela; /* PLT relocation entries with addend */ + unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ + const Elf_Sym *symtab; /* Symbol table */ + const char *strtab; /* String table */ + unsigned long strsize; /* Size in bytes of string table */ + + 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 */ + + const Elf_Hashelt *buckets; /* Hash table buckets array */ + unsigned long nbuckets; /* Number of buckets */ + const Elf_Hashelt *chains; /* Hash table chain array */ + unsigned long nchains; /* Number of entries in chain array */ + + Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/ + Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */ + Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */ + Elf32_Word shift2_gnu; /* Bloom filter shift count */ + Elf32_Word dynsymcount; /* Total entries in dynsym table */ + const Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */ + const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */ + const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */ + + const char *rpath; /* Search path specified in object */ + const char *runpath; /* Search path with different priority */ + Needed_Entry *needed; /* Shared objects needed by this one (%) */ + Needed_Entry *needed_filtees; + Needed_Entry *needed_aux_filtees; + + STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we + know about. */ + Ver_Entry *vertab; /* Versions required /defined by this object */ + int vernum; /* Number of entries in vertab */ + + Elf_Addr init; /* Initialization function to call */ + Elf_Addr fini; /* Termination function to call */ + Elf_Addr preinit_array; /* Pre-initialization array of functions */ + Elf_Addr init_array; /* Initialization array of functions */ + Elf_Addr fini_array; /* Termination array of functions */ + int preinit_array_num; /* Number of entries in preinit_array */ + int init_array_num; /* Number of entries in init_array */ + int fini_array_num; /* Number of entries in fini_array */ + + int32_t osrel; /* OSREL note value */ + uint32_t fctl0; /* FEATURE_CONTROL note desc[0] value */ + + bool mainprog : 1; /* True if this is the main program */ + bool rtld : 1; /* True if this is the dynamic linker */ + bool relocated : 1; /* True if processed by relocate_objects() */ + bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ + bool textrel : 1; /* True if there are relocations to text seg */ + bool symbolic : 1; /* True if generated with "-Bsymbolic" */ + bool deepbind : 1; /* True if loaded with RTLD_DEEPBIND" */ + bool bind_now : 1; /* True if all relocations should be made first */ + bool traced : 1; /* Already printed in ldd trace output */ + bool jmpslots_done : 1; /* Already have relocated the jump slots */ + bool init_done : 1; /* Already have added object to init list */ + bool tls_static : 1; /* Already allocated offset for static TLS */ + bool tls_dynamic : 1; /* A non-static DTV entry has been allocated */ + bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ + bool z_origin : 1; /* Process rpath and soname tokens */ + bool z_nodelete : 1; /* Do not unload the object and dependencies */ + bool z_noopen : 1; /* Do not load on dlopen */ + bool z_loadfltr : 1; /* Immediately load filtees */ + bool z_interpose : 1; /* Interpose all objects but main */ + bool z_nodeflib : 1; /* Don't search default library path */ + bool z_global : 1; /* Make the object global */ + bool z_pie : 1; /* Object proclaimed itself PIE executable */ + bool z_initfirst : 1; /* Proceed initializers before other objects */ + bool static_tls : 1; /* Needs static TLS allocation */ + bool static_tls_copied : 1; /* Needs static TLS copying */ + bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ + bool init_scanned: 1; /* Object is already on init list. */ + bool on_fini_list: 1; /* Object is already on fini list. */ + bool dag_inited : 1; /* Object has its DAG initialized. */ + bool filtees_loaded : 1; /* Filtees loaded */ + bool filtees_loading : 1; /* In process of filtees loading */ + bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ + bool irelative_nonplt : 1; /* Object has R_MACHDEP_IRELATIVE non-plt relocs */ + bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ + bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ + bool ifuncs_resolved : 1; /* Object ifuncs were already resolved */ + bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ + bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ + bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ + bool dlopened : 1; /* dlopen()-ed (vs. load statically) */ + bool marker : 1; /* marker on the global obj list */ + bool unholdfree : 1; /* unmap upon last unhold */ + bool doomed : 1; /* Object cannot be referenced */ + + MD_OBJ_ENTRY + + struct link_map linkmap; /* For GDB and dlinfo() */ + 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 *priv; /* Platform-dependent */ +} Obj_Entry; + +#define RTLD_MAGIC 0xd550b87a +#define RTLD_VERSION 1 + +TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry); + +#define RTLD_STATIC_TLS_EXTRA 128 + +/* Flags to be passed into symlook_ family of functions. */ +#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ +#define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by + dlsym. */ +#define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ +#define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in + reloc_non_plt(). */ + +/* Flags for load_object(). */ +#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ +#define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ +#define RTLD_LO_TRACE 0x04 /* Only tracing. */ +#define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ +#define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ +#define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the + initialization during the image start. */ +#define RTLD_LO_IGNSTLS 0x40 /* Do not allocate static TLS */ +#define RTLD_LO_DEEPBIND 0x80 /* Force symbolic for this object */ + +/* + * Symbol cache entry used during relocation to avoid multiple lookups + * of the same symbol. + */ +typedef struct Struct_SymCache { + const Elf_Sym *sym; /* Symbol table entry */ + const Obj_Entry *obj; /* Shared object which defines it */ +} SymCache; + +/* + * This structure provides a reentrant way to keep a list of objects and + * check which ones have already been processed in some way. + */ +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; + +struct Struct_RtldLockState { + int lockstate; + sigjmp_buf env; +}; + +struct fill_search_info_args { + int request; + unsigned int flags; + struct dl_serinfo *serinfo; + struct dl_serpath *serpath; + char *strspace; +}; + +/* + * The pack of arguments and results for the symbol lookup functions. + */ +typedef struct Struct_SymLook { + const char *name; + unsigned long hash; + uint32_t hash_gnu; + const Ver_Entry *ventry; + int flags; + const Obj_Entry *defobj_out; + const Elf_Sym *sym_out; + struct Struct_RtldLockState *lockstate; +} SymLook; + +enum { + LD_BIND_NOW = 0, + LD_PRELOAD, + LD_LIBMAP, + LD_LIBRARY_PATH, + LD_LIBRARY_PATH_FDS, + LD_LIBMAP_DISABLE, + LD_BIND_NOT, + LD_DEBUG, + LD_ELF_HINTS_PATH, + LD_LOADFLTR, + LD_LIBRARY_PATH_RPATH, + LD_PRELOAD_FDS, + LD_DYNAMIC_WEAK, + LD_TRACE_LOADED_OBJECTS, + LD_UTRACE, + LD_DUMP_REL_PRE, + LD_DUMP_REL_POST, + LD_TRACE_LOADED_OBJECTS_PROGNAME, + LD_TRACE_LOADED_OBJECTS_FMT1, + LD_TRACE_LOADED_OBJECTS_FMT2, + LD_TRACE_LOADED_OBJECTS_ALL, + LD_SHOW_AUXV, + LD_STATIC_TLS_EXTRA, + LD_NO_DL_ITERATE_PHDR_AFTER_FORK, +}; + +void _rtld_error(const char *, ...) __printflike(1, 2) __exported; +void rtld_die(void) __dead2; +const char *rtld_strerror(int); +Obj_Entry *map_object(int, const char *, const struct stat *, bool); +void *xcalloc(size_t, size_t); +void *xmalloc(size_t); +char *xstrdup(const char *); +void *xmalloc_aligned(size_t size, size_t align, size_t offset); +extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; +extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ +extern bool ld_bind_not; +extern bool ld_fast_sigblock; + +void dump_relocations(Obj_Entry *); +void dump_obj_relocations(Obj_Entry *); +void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); +void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); + +/* + * Function declarations. + */ +const char *ld_get_env_var(int idx); +uintptr_t rtld_round_page(uintptr_t); +uintptr_t rtld_trunc_page(uintptr_t); +Elf32_Word elf_hash(const char *); +const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, + const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); +void lockdflt_init(void); +void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); +Obj_Entry *globallist_curr(const Obj_Entry *obj); +Obj_Entry *globallist_next(const Obj_Entry *obj); +void obj_free(Obj_Entry *); +Obj_Entry *obj_new(void); +Obj_Entry *obj_from_addr(const void *); +void _rtld_bind_start(void); +void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); +void symlook_init(SymLook *, const char *); +int symlook_obj(SymLook *, const Obj_Entry *); +void *tls_get_addr_common(struct tcb *tcb, int index, size_t offset); +void *allocate_tls(Obj_Entry *, void *, size_t, size_t); +void free_tls(void *, size_t, size_t); +void *allocate_module_tls(struct tcb *tcb, int index); +bool allocate_tls_offset(Obj_Entry *obj); +void free_tls_offset(Obj_Entry *obj); +const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); +int convert_prot(int elfflags); +bool check_elf_headers(const Elf_Ehdr *hdr, const char *path); + +/* + * MD function declarations. + */ +int do_copy_relocations(Obj_Entry *); +int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, + struct Struct_RtldLockState *); +int reloc_plt(Obj_Entry *, int flags, struct Struct_RtldLockState *); +int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); +int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); +int reloc_iresolve_nonplt(Obj_Entry *, struct Struct_RtldLockState *); +int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); +void ifunc_init(Elf_Auxinfo *[__min_size(AT_COUNT)]); +void init_pltgot(Obj_Entry *); +void allocate_initial_tls(Obj_Entry *); + +#endif /* } */ |