1/*-
2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 * $FreeBSD: releng/11.0/libexec/rtld-elf/rtld.h 296319 2016-03-02 16:36:24Z kib $
26 */
27
28#ifndef RTLD_H /* { */
29#define RTLD_H 1
30
31#include <machine/elf.h>
32#include <sys/types.h>
33#include <sys/queue.h>
34
35#include <elf-hints.h>
36#include <link.h>
37#include <stdarg.h>
38#include <setjmp.h>
39#include <stddef.h>
40
41#include "rtld_lock.h"
42#include "rtld_machdep.h"
43
44#define NEW(type)	((type *) xmalloc(sizeof(type)))
45#define CNEW(type)	((type *) xcalloc(1, sizeof(type)))
46
47/* We might as well do booleans like C++. */
48typedef unsigned char bool;
49#define false	0
50#define true	1
51
52extern size_t tls_last_offset;
53extern size_t tls_last_size;
54extern size_t tls_static_space;
55extern int tls_dtv_generation;
56extern int tls_max_index;
57
58extern int npagesizes;
59extern size_t *pagesizes;
60
61extern int main_argc;
62extern char **main_argv;
63extern char **environ;
64
65struct stat;
66struct Struct_Obj_Entry;
67
68/* Lists of shared objects */
69typedef struct Struct_Objlist_Entry {
70    STAILQ_ENTRY(Struct_Objlist_Entry) link;
71    struct Struct_Obj_Entry *obj;
72} Objlist_Entry;
73
74typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
75
76/* Types of init and fini functions */
77typedef void (*InitFunc)(void);
78typedef void (*InitArrFunc)(int, char **, char **);
79
80/* Lists of shared object dependencies */
81typedef struct Struct_Needed_Entry {
82    struct Struct_Needed_Entry *next;
83    struct Struct_Obj_Entry *obj;
84    unsigned long name;		/* Offset of name in string table */
85} Needed_Entry;
86
87typedef struct Struct_Name_Entry {
88    STAILQ_ENTRY(Struct_Name_Entry) link;
89    char   name[1];
90} Name_Entry;
91
92/* Lock object */
93typedef struct Struct_LockInfo {
94    void *context;		/* Client context for creating locks */
95    void *thelock;		/* The one big lock */
96    /* Debugging aids. */
97    volatile int rcount;	/* Number of readers holding lock */
98    volatile int wcount;	/* Number of writers holding lock */
99    /* Methods */
100    void *(*lock_create)(void *context);
101    void (*rlock_acquire)(void *lock);
102    void (*wlock_acquire)(void *lock);
103    void (*rlock_release)(void *lock);
104    void (*wlock_release)(void *lock);
105    void (*lock_destroy)(void *lock);
106    void (*context_destroy)(void *context);
107} LockInfo;
108
109typedef struct Struct_Ver_Entry {
110	Elf_Word     hash;
111	unsigned int flags;
112	const char  *name;
113	const char  *file;
114} Ver_Entry;
115
116typedef struct Struct_Sym_Match_Result {
117    const Elf_Sym *sym_out;
118    const Elf_Sym *vsymp;
119    int vcount;
120} Sym_Match_Result;
121
122#define VER_INFO_HIDDEN	0x01
123
124/*
125 * Shared object descriptor.
126 *
127 * Items marked with "(%)" are dynamically allocated, and must be freed
128 * when the structure is destroyed.
129 *
130 * CAUTION: It appears that the JDK port peeks into these structures.
131 * It looks at "next" and "mapbase" at least.  Don't add new members
132 * near the front, until this can be straightened out.
133 */
134typedef struct Struct_Obj_Entry {
135    /*
136     * These two items have to be set right for compatibility with the
137     * original ElfKit crt1.o.
138     */
139    Elf_Size magic;		/* Magic number (sanity check) */
140    Elf_Size version;		/* Version number of struct format */
141
142    TAILQ_ENTRY(Struct_Obj_Entry) next;
143    char *path;			/* Pathname of underlying file (%) */
144    char *origin_path;		/* Directory path of origin file */
145    int refcount;
146    int dl_refcount;		/* Number of times loaded by dlopen */
147
148    /* These items are computed by map_object() or by digest_phdr(). */
149    caddr_t mapbase;		/* Base address of mapped region */
150    size_t mapsize;		/* Size of mapped region in bytes */
151    size_t textsize;		/* Size of text segment in bytes */
152    Elf_Addr vaddrbase;		/* Base address in shared object file */
153    caddr_t relocbase;		/* Relocation constant = mapbase - vaddrbase */
154    const Elf_Dyn *dynamic;	/* Dynamic section */
155    caddr_t entry;		/* Entry point */
156    const Elf_Phdr *phdr;	/* Program header if it is mapped, else NULL */
157    size_t phsize;		/* Size of program header in bytes */
158    const char *interp;		/* Pathname of the interpreter, if any */
159    Elf_Word stack_flags;
160
161    /* TLS information */
162    int tlsindex;		/* Index in DTV for this module */
163    void *tlsinit;		/* Base address of TLS init block */
164    size_t tlsinitsize;		/* Size of TLS init block for this module */
165    size_t tlssize;		/* Size of TLS block for this module */
166    size_t tlsoffset;		/* Offset of static TLS block for this module */
167    size_t tlsalign;		/* Alignment of static TLS block */
168
169    caddr_t relro_page;
170    size_t relro_size;
171
172    /* Items from the dynamic section. */
173    Elf_Addr *pltgot;		/* PLT or GOT, depending on architecture */
174    const Elf_Rel *rel;		/* Relocation entries */
175    unsigned long relsize;	/* Size in bytes of relocation info */
176    const Elf_Rela *rela;	/* Relocation entries with addend */
177    unsigned long relasize;	/* Size in bytes of addend relocation info */
178    const Elf_Rel *pltrel;	/* PLT relocation entries */
179    unsigned long pltrelsize;	/* Size in bytes of PLT relocation info */
180    const Elf_Rela *pltrela;	/* PLT relocation entries with addend */
181    unsigned long pltrelasize;	/* Size in bytes of PLT addend reloc info */
182    const Elf_Sym *symtab;	/* Symbol table */
183    const char *strtab;		/* String table */
184    unsigned long strsize;	/* Size in bytes of string table */
185#ifdef __mips__
186    Elf_Word local_gotno;	/* Number of local GOT entries */
187    Elf_Word symtabno;		/* Number of dynamic symbols */
188    Elf_Word gotsym;		/* First dynamic symbol in GOT */
189#endif
190#ifdef __powerpc64__
191    Elf_Addr glink;		/* GLINK PLT call stub section */
192#endif
193
194    const Elf_Verneed *verneed; /* Required versions. */
195    Elf_Word verneednum;	/* Number of entries in verneed table */
196    const Elf_Verdef  *verdef;	/* Provided versions. */
197    Elf_Word verdefnum;		/* Number of entries in verdef table */
198    const Elf_Versym *versyms;  /* Symbol versions table */
199
200    const Elf_Hashelt *buckets;	/* Hash table buckets array */
201    unsigned long nbuckets;	/* Number of buckets */
202    const Elf_Hashelt *chains;	/* Hash table chain array */
203    unsigned long nchains;	/* Number of entries in chain array */
204
205    Elf32_Word nbuckets_gnu;		/* Number of GNU hash buckets*/
206    Elf32_Word symndx_gnu;		/* 1st accessible symbol on dynsym table */
207    Elf32_Word maskwords_bm_gnu;  	/* Bloom filter words - 1 (bitmask) */
208    Elf32_Word shift2_gnu;		/* Bloom filter shift count */
209    Elf32_Word dynsymcount;		/* Total entries in dynsym table */
210    Elf_Addr *bloom_gnu;		/* Bloom filter used by GNU hash func */
211    const Elf_Hashelt *buckets_gnu;	/* GNU hash table bucket array */
212    const Elf_Hashelt *chain_zero_gnu;	/* GNU hash table value array (Zeroed) */
213
214    char *rpath;		/* Search path specified in object */
215    char *runpath;		/* Search path with different priority */
216    Needed_Entry *needed;	/* Shared objects needed by this one (%) */
217    Needed_Entry *needed_filtees;
218    Needed_Entry *needed_aux_filtees;
219
220    STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we
221					       know about. */
222    Ver_Entry *vertab;		/* Versions required /defined by this object */
223    int vernum;			/* Number of entries in vertab */
224
225    Elf_Addr init;		/* Initialization function to call */
226    Elf_Addr fini;		/* Termination function to call */
227    Elf_Addr preinit_array;	/* Pre-initialization array of functions */
228    Elf_Addr init_array;	/* Initialization array of functions */
229    Elf_Addr fini_array;	/* Termination array of functions */
230    int preinit_array_num;	/* Number of entries in preinit_array */
231    int init_array_num; 	/* Number of entries in init_array */
232    int fini_array_num; 	/* Number of entries in fini_array */
233
234    int32_t osrel;		/* OSREL note value */
235
236    bool mainprog : 1;		/* True if this is the main program */
237    bool rtld : 1;		/* True if this is the dynamic linker */
238    bool relocated : 1;		/* True if processed by relocate_objects() */
239    bool ver_checked : 1;	/* True if processed by rtld_verify_object_versions */
240    bool textrel : 1;		/* True if there are relocations to text seg */
241    bool symbolic : 1;		/* True if generated with "-Bsymbolic" */
242    bool bind_now : 1;		/* True if all relocations should be made first */
243    bool traced : 1;		/* Already printed in ldd trace output */
244    bool jmpslots_done : 1;	/* Already have relocated the jump slots */
245    bool init_done : 1;		/* Already have added object to init list */
246    bool tls_done : 1;		/* Already allocated offset for static TLS */
247    bool phdr_alloc : 1;	/* Phdr is allocated and needs to be freed. */
248    bool z_origin : 1;		/* Process rpath and soname tokens */
249    bool z_nodelete : 1;	/* Do not unload the object and dependencies */
250    bool z_noopen : 1;		/* Do not load on dlopen */
251    bool z_loadfltr : 1;	/* Immediately load filtees */
252    bool z_interpose : 1;	/* Interpose all objects but main */
253    bool z_nodeflib : 1;	/* Don't search default library path */
254    bool z_global : 1;		/* Make the object global */
255    bool ref_nodel : 1;		/* Refcount increased to prevent dlclose */
256    bool init_scanned: 1;	/* Object is already on init list. */
257    bool on_fini_list: 1;	/* Object is already on fini list. */
258    bool dag_inited : 1;	/* Object has its DAG initialized. */
259    bool filtees_loaded : 1;	/* Filtees loaded */
260    bool irelative : 1;		/* Object has R_MACHDEP_IRELATIVE relocs */
261    bool gnu_ifunc : 1;		/* Object has references to STT_GNU_IFUNC */
262    bool non_plt_gnu_ifunc : 1;	/* Object has non-plt IFUNC references */
263    bool crt_no_init : 1;	/* Object' crt does not call _init/_fini */
264    bool valid_hash_sysv : 1;	/* A valid System V hash hash tag is available */
265    bool valid_hash_gnu : 1;	/* A valid GNU hash tag is available */
266    bool dlopened : 1;		/* dlopen()-ed (vs. load statically) */
267    bool marker : 1;		/* marker on the global obj list */
268
269    struct link_map linkmap;	/* For GDB and dlinfo() */
270    Objlist dldags;		/* Object belongs to these dlopened DAGs (%) */
271    Objlist dagmembers;		/* DAG has these members (%) */
272    dev_t dev;			/* Object's filesystem's device */
273    ino_t ino;			/* Object's inode number */
274    void *priv;			/* Platform-dependent */
275} Obj_Entry;
276
277#define RTLD_MAGIC	0xd550b87a
278#define RTLD_VERSION	1
279
280TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry);
281
282#define RTLD_STATIC_TLS_EXTRA	128
283
284/* Flags to be passed into symlook_ family of functions. */
285#define SYMLOOK_IN_PLT	0x01	/* Lookup for PLT symbol */
286#define SYMLOOK_DLSYM	0x02	/* Return newest versioned symbol. Used by
287				   dlsym. */
288#define	SYMLOOK_EARLY	0x04	/* Symlook is done during initialization. */
289#define	SYMLOOK_IFUNC	0x08	/* Allow IFUNC processing in
290				   reloc_non_plt(). */
291
292/* Flags for load_object(). */
293#define	RTLD_LO_NOLOAD	0x01	/* dlopen() specified RTLD_NOLOAD. */
294#define	RTLD_LO_DLOPEN	0x02	/* Load_object() called from dlopen(). */
295#define	RTLD_LO_TRACE	0x04	/* Only tracing. */
296#define	RTLD_LO_NODELETE 0x08	/* Loaded object cannot be closed. */
297#define	RTLD_LO_FILTEES 0x10	/* Loading filtee. */
298#define	RTLD_LO_EARLY	0x20	/* Do not call ctors, postpone it to the
299				   initialization during the image start. */
300
301/*
302 * Symbol cache entry used during relocation to avoid multiple lookups
303 * of the same symbol.
304 */
305typedef struct Struct_SymCache {
306    const Elf_Sym *sym;		/* Symbol table entry */
307    const Obj_Entry *obj;	/* Shared object which defines it */
308} SymCache;
309
310/*
311 * This structure provides a reentrant way to keep a list of objects and
312 * check which ones have already been processed in some way.
313 */
314typedef struct Struct_DoneList {
315    const Obj_Entry **objs;		/* Array of object pointers */
316    unsigned int num_alloc;		/* Allocated size of the array */
317    unsigned int num_used;		/* Number of array slots used */
318} DoneList;
319
320struct Struct_RtldLockState {
321	int lockstate;
322	sigjmp_buf env;
323};
324
325struct fill_search_info_args {
326	int request;
327	unsigned int flags;
328	struct dl_serinfo *serinfo;
329	struct dl_serpath *serpath;
330	char *strspace;
331};
332
333/*
334 * The pack of arguments and results for the symbol lookup functions.
335 */
336typedef struct Struct_SymLook {
337    const char *name;
338    unsigned long hash;
339    uint32_t hash_gnu;
340    const Ver_Entry *ventry;
341    int flags;
342    const Obj_Entry *defobj_out;
343    const Elf_Sym *sym_out;
344    struct Struct_RtldLockState *lockstate;
345} SymLook;
346
347void _rtld_error(const char *, ...) __printflike(1, 2) __exported;
348void rtld_die(void) __dead2;
349const char *rtld_strerror(int);
350Obj_Entry *map_object(int, const char *, const struct stat *);
351void *xcalloc(size_t, size_t);
352void *xmalloc(size_t);
353char *xstrdup(const char *);
354void *malloc_aligned(size_t size, size_t align);
355void free_aligned(void *ptr);
356extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
357extern Elf_Sym sym_zero;	/* For resolving undefined weak refs. */
358
359void dump_relocations(Obj_Entry *);
360void dump_obj_relocations(Obj_Entry *);
361void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
362void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
363
364/*
365 * Function declarations.
366 */
367unsigned long elf_hash(const char *);
368const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *,
369  const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
370void init_pltgot(Obj_Entry *);
371void lockdflt_init(void);
372void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr);
373Obj_Entry *globallist_curr(const Obj_Entry *obj);
374Obj_Entry *globallist_next(const Obj_Entry *obj);
375void obj_free(Obj_Entry *);
376Obj_Entry *obj_new(void);
377void _rtld_bind_start(void);
378void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def);
379void symlook_init(SymLook *, const char *);
380int symlook_obj(SymLook *, const Obj_Entry *);
381void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset);
382void *allocate_tls(Obj_Entry *, void *, size_t, size_t);
383void free_tls(void *, size_t, size_t);
384void *allocate_module_tls(int index);
385bool allocate_tls_offset(Obj_Entry *obj);
386void free_tls_offset(Obj_Entry *obj);
387const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long);
388int convert_prot(int elfflags);
389
390/*
391 * MD function declarations.
392 */
393int do_copy_relocations(Obj_Entry *);
394int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags,
395    struct Struct_RtldLockState *);
396int reloc_plt(Obj_Entry *);
397int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *);
398int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *);
399int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *);
400void allocate_initial_tls(Obj_Entry *);
401
402#endif /* } */
403