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: src/libexec/rtld-elf/rtld.h,v 1.50 2011/02/09 09:20:27 kib Exp $ 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 <setjmp.h> 38 #include <stddef.h> 39 40 #include "rtld_lock.h" 41 #include "rtld_machdep.h" 42 43 #ifndef STANDARD_LIBRARY_PATH 44 #define STANDARD_LIBRARY_PATH "/usr/lib" 45 #endif 46 47 #define NEW(type) ((type *) xmalloc(sizeof(type))) 48 #define CNEW(type) ((type *) xcalloc(sizeof(type))) 49 50 /* We might as well do booleans like C++. */ 51 typedef unsigned char bool; 52 #define false 0 53 #define true 1 54 55 extern size_t tls_last_offset; 56 extern size_t tls_last_size; 57 extern size_t tls_static_space; 58 extern int tls_dtv_generation; 59 extern int tls_max_index; 60 61 struct stat; 62 struct Struct_Obj_Entry; 63 64 /* Lists of shared objects */ 65 typedef struct Struct_Objlist_Entry { 66 STAILQ_ENTRY(Struct_Objlist_Entry) link; 67 struct Struct_Obj_Entry *obj; 68 } Objlist_Entry; 69 70 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 71 72 /* Types of init and fini functions */ 73 typedef void (*InitFunc)(void); 74 75 /* Lists of shared object dependencies */ 76 typedef struct Struct_Needed_Entry { 77 struct Struct_Needed_Entry *next; 78 struct Struct_Obj_Entry *obj; 79 unsigned long name; /* Offset of name in string table */ 80 } Needed_Entry; 81 82 typedef struct Struct_Name_Entry { 83 STAILQ_ENTRY(Struct_Name_Entry) link; 84 char name[1]; 85 } Name_Entry; 86 87 /* Lock object */ 88 typedef struct Struct_LockInfo { 89 void *context; /* Client context for creating locks */ 90 void *thelock; /* The one big lock */ 91 /* Debugging aids. */ 92 volatile int rcount; /* Number of readers holding lock */ 93 volatile int wcount; /* Number of writers holding lock */ 94 /* Methods */ 95 void *(*lock_create)(void *context); 96 void (*rlock_acquire)(void *lock); 97 void (*wlock_acquire)(void *lock); 98 void (*rlock_release)(void *lock); 99 void (*wlock_release)(void *lock); 100 void (*lock_destroy)(void *lock); 101 void (*context_destroy)(void *context); 102 } LockInfo; 103 104 typedef struct Struct_Ver_Entry { 105 Elf_Word hash; 106 unsigned int flags; 107 const char *name; 108 const char *file; 109 } Ver_Entry; 110 111 #define VER_INFO_HIDDEN 0x01 112 113 /* 114 * Shared object descriptor. 115 * 116 * Items marked with "(%)" are dynamically allocated, and must be freed 117 * when the structure is destroyed. 118 * 119 * CAUTION: It appears that the JDK port peeks into these structures. 120 * It looks at "next" and "mapbase" at least. Don't add new members 121 * near the front, until this can be straightened out. 122 */ 123 typedef struct Struct_Obj_Entry { 124 /* 125 * These two items have to be set right for compatibility with the 126 * original ElfKit crt1.o. 127 */ 128 Elf_Size magic; /* Magic number (sanity check) */ 129 Elf_Size version; /* Version number of struct format */ 130 131 struct Struct_Obj_Entry *next; 132 char *path; /* Pathname of underlying file (%) */ 133 char *origin_path; /* Directory path of origin file */ 134 int refcount; 135 int dl_refcount; /* Number of times loaded by dlopen */ 136 137 /* These items are computed by map_object() or by digest_phdr(). */ 138 caddr_t mapbase; /* Base address of mapped region */ 139 size_t mapsize; /* Size of mapped region in bytes */ 140 size_t textsize; /* Size of text segment in bytes */ 141 Elf_Addr vaddrbase; /* Base address in shared object file */ 142 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 143 const Elf_Dyn *dynamic; /* Dynamic section */ 144 caddr_t entry; /* Entry point */ 145 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 146 size_t phsize; /* Size of program header in bytes */ 147 const char *interp; /* Pathname of the interpreter, if any */ 148 149 /* TLS information */ 150 int tlsindex; /* Index in DTV for this module */ 151 void *tlsinit; /* Base address of TLS init block */ 152 size_t tlsinitsize; /* Size of TLS init block for this module */ 153 size_t tlssize; /* Size of TLS block for this module */ 154 size_t tlsoffset; /* Offset of static TLS block for this module */ 155 size_t tlsalign; /* Alignment of static TLS block */ 156 157 /* Items from the dynamic section. */ 158 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 159 const Elf_Rel *rel; /* Relocation entries */ 160 unsigned long relsize; /* Size in bytes of relocation info */ 161 const Elf_Rela *rela; /* Relocation entries with addend */ 162 unsigned long relasize; /* Size in bytes of addend relocation info */ 163 const Elf_Rel *pltrel; /* PLT relocation entries */ 164 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 165 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 166 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 167 const Elf_Sym *symtab; /* Symbol table */ 168 const char *strtab; /* String table */ 169 unsigned long strsize; /* Size in bytes of string table */ 170 171 const Elf_Verneed *verneed; /* Required versions. */ 172 Elf_Word verneednum; /* Number of entries in verneed table */ 173 const Elf_Verdef *verdef; /* Provided versions. */ 174 Elf_Word verdefnum; /* Number of entries in verdef table */ 175 const Elf_Versym *versyms; /* Symbol versions table */ 176 177 const Elf_Hashelt *buckets; /* Hash table buckets array */ 178 unsigned long nbuckets; /* Number of buckets */ 179 const Elf_Hashelt *chains; /* Hash table chain array */ 180 unsigned long nchains; /* Number of chains */ 181 182 char *rpath; /* Search path specified in object */ 183 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 184 185 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 186 know about. */ 187 Ver_Entry *vertab; /* Versions required /defined by this object */ 188 int vernum; /* Number of entries in vertab */ 189 190 Elf_Addr init; /* Initialization function to call */ 191 Elf_Addr fini; /* Termination function to call */ 192 193 bool mainprog : 1; /* True if this is the main program */ 194 bool rtld : 1; /* True if this is the dynamic linker */ 195 bool textrel : 1; /* True if there are relocations to text seg */ 196 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 197 bool bind_now : 1; /* True if all relocations should be made first */ 198 bool traced : 1; /* Already printed in ldd trace output */ 199 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 200 bool init_done : 1; /* Already have added object to init list */ 201 bool tls_done : 1; /* Already allocated offset for static TLS */ 202 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 203 bool z_origin : 1; /* Process rpath and soname tokens */ 204 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 205 bool z_noopen : 1; /* Do not load on dlopen */ 206 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 207 bool init_scanned: 1; /* Object is already on init list. */ 208 bool on_fini_list: 1; /* Object is already on fini list. */ 209 bool dag_inited : 1; /* Object has its DAG initialized. */ 210 211 struct link_map linkmap; /* For GDB and dlinfo() */ 212 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 213 Objlist dagmembers; /* DAG has these members (%) */ 214 dev_t dev; /* Object's filesystem's device */ 215 ino_t ino; /* Object's inode number */ 216 void *priv; /* Platform-dependant */ 217 } Obj_Entry; 218 219 #define RTLD_MAGIC 0xd550b87a 220 #define RTLD_VERSION 1 221 222 /* Flags to be passed into symlook_ family of functions. */ 223 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 224 #define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by 225 dlsym. */ 226 227 /* Flags for load_object(). */ 228 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 229 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 230 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 231 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 232 233 /* 234 * Symbol cache entry used during relocation to avoid multiple lookups 235 * of the same symbol. 236 */ 237 typedef struct Struct_SymCache { 238 const Elf_Sym *sym; /* Symbol table entry */ 239 const Obj_Entry *obj; /* Shared object which defines it */ 240 } SymCache; 241 242 struct Struct_RtldLockState { 243 int lockstate; 244 sigjmp_buf env; 245 }; 246 247 void _rtld_error(const char *, ...) __printflike(1, 2); 248 Obj_Entry *map_object(int, const char *, const struct stat *); 249 void *xcalloc(size_t); 250 void *xmalloc(size_t); 251 char *xstrdup(const char *); 252 void *xrealloc(void *, size_t); 253 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 254 255 void dump_relocations(Obj_Entry *); 256 void dump_obj_relocations(Obj_Entry *); 257 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 258 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 259 260 /* 261 * Function declarations. 262 */ 263 const char *basename(const char *); 264 unsigned long elf_hash(const char *); 265 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 266 const Obj_Entry **, int, SymCache *); 267 void init_pltgot(Obj_Entry *); 268 void lockdflt_init(void); 269 void obj_free(Obj_Entry *); 270 Obj_Entry *obj_new(void); 271 void _rtld_bind_start(void); 272 const Elf_Sym *symlook_obj(const char *, unsigned long, const Obj_Entry *, 273 const Ver_Entry *, int); 274 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 275 struct tls_tcb *allocate_tls(Obj_Entry *); 276 void free_tls(struct tls_tcb *); 277 void *allocate_module_tls(int index); 278 bool allocate_tls_offset(Obj_Entry *obj); 279 void free_tls_offset(Obj_Entry *obj); 280 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 281 282 /* 283 * MD function declarations. 284 */ 285 int do_copy_relocations(Obj_Entry *); 286 int reloc_non_plt(Obj_Entry *, Obj_Entry *); 287 int reloc_plt(Obj_Entry *); 288 int reloc_jmpslots(Obj_Entry *); 289 void allocate_initial_tls(Obj_Entry *); 290 291 #endif /* } */ 292