libexec/ld.elf_so/rtld.h

   1 /*      $NetBSD: rtld.h,v 1.81 2009/09/24 21:21:34 pooka Exp $   */
   2
   3 /*
   4  * Copyright 1996 John D. Polstra.
   5  * Copyright 1996 Matt Thomas <matt@3am-software.com>
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by John Polstra.
  19  * 4. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #ifndef RTLD_H
  35 #define RTLD_H
  36
  37 #include <dlfcn.h>
  38 #include <stdbool.h>
  39 #include <stddef.h>
  40 #include <sys/param.h>
  41 #include <sys/types.h>
  42 #include <sys/queue.h>
  43 #include <sys/exec_elf.h>
  44 #include "rtldenv.h"
  45 #include "link.h"
  46
  47 #if defined(_RTLD_SOURCE)
  48
  49 #ifndef RTLD_DEFAULT_LIBRARY_PATH
  50 #define RTLD_DEFAULT_LIBRARY_PATH       "/usr/lib"
  51 #endif
  52 #define _PATH_LD_HINTS                  "/etc/ld.so.conf"
  53
  54 extern size_t _rtld_pagesz;
  55
  56 #define round_down(x)   ((x) & ~(_rtld_pagesz - 1))
  57 #define round_up(x)     round_down((x) + _rtld_pagesz - 1)
  58
  59 #define NEW(type)       ((type *) xmalloc(sizeof(type)))
  60 #define CNEW(type)      ((type *) xcalloc(sizeof(type)))
  61
  62 #endif /* _RTLD_SOURCE */
  63
  64 /*
  65  * C++ has mandated the use of the following keywords for its new boolean
  66  * type.  We might as well follow their lead.
  67  */
  68 struct Struct_Obj_Entry;
  69
  70 typedef struct Struct_Objlist_Entry {
  71         SIMPLEQ_ENTRY(Struct_Objlist_Entry) link;
  72         struct Struct_Obj_Entry *obj;
  73 } Objlist_Entry;
  74
  75 typedef SIMPLEQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
  76
  77 typedef struct Struct_Needed_Entry {
  78         struct Struct_Needed_Entry *next;
  79         struct Struct_Obj_Entry *obj;
  80         unsigned long   name;   /* Offset of name in string table */
  81 } Needed_Entry;
  82
  83 typedef struct _rtld_search_path_t {
  84         struct _rtld_search_path_t *sp_next;
  85         const char     *sp_path;
  86         size_t          sp_pathlen;
  87 } Search_Path;
  88
  89
  90 #define RTLD_MAX_ENTRY 10
  91 #define RTLD_MAX_LIBRARY 4
  92 #define RTLD_MAX_CTL 2
  93 typedef struct _rtld_library_xform_t {
  94         struct _rtld_library_xform_t *next;
  95         char *name;
  96         const char *ctlname;
  97         struct {
  98                 char *value;
  99                 char *library[RTLD_MAX_LIBRARY];
 100         } entry[RTLD_MAX_ENTRY];
 101 } Library_Xform;
 102
 103 /*
 104  * Shared object descriptor.
 105  *
 106  * Items marked with "(%)" are dynamically allocated, and must be freed
 107  * when the structure is destroyed.
 108  */
 109
 110 #define RTLD_MAGIC      0xd550b87a
 111 #define RTLD_VERSION    1
 112 #define RTLD_MAIN       0x800
 113
 114 typedef struct Struct_Obj_Entry {
 115         Elf32_Word      magic;          /* Magic number (sanity check) */
 116         Elf32_Word      version;        /* Version number of struct format */
 117
 118         struct Struct_Obj_Entry *next;
 119         char           *path;           /* Pathname of underlying file (%) */
 120         int             refcount;
 121         int             dl_refcount;    /* Number of times loaded by dlopen */
 122
 123         /* These items are computed by map_object() or by digest_phdr(). */
 124         caddr_t         mapbase;        /* Base address of mapped region */
 125         size_t          mapsize;        /* Size of mapped region in bytes */
 126         size_t          textsize;       /* Size of text segment in bytes */
 127         Elf_Addr        vaddrbase;      /* Base address in shared object file */
 128         caddr_t         relocbase;      /* Reloc const = mapbase - *vaddrbase */
 129         Elf_Dyn        *dynamic;        /* Dynamic section */
 130         caddr_t         entry;          /* Entry point */
 131         const Elf_Phdr *__junk001;
 132         size_t          pathlen;        /* Pathname length */
 133         void            *ehdr;
 134
 135         /* Items from the dynamic section. */
 136         Elf_Addr       *pltgot;         /* PLTGOT table */
 137         const Elf_Rel  *rel;            /* Relocation entries */
 138         const Elf_Rel  *rellim;         /* Limit of Relocation entries */
 139         const Elf_Rela *rela;           /* Relocation entries */
 140         const Elf_Rela *relalim;        /* Limit of Relocation entries */
 141         const Elf_Rel  *pltrel;         /* PLT relocation entries */
 142         const Elf_Rel  *pltrellim;      /* Limit of PLT relocation entries */
 143         const Elf_Rela *pltrela;        /* PLT relocation entries */
 144         const Elf_Rela *pltrelalim;     /* Limit of PLT relocation entries */
 145         const Elf_Sym  *symtab;         /* Symbol table */
 146         const char     *strtab;         /* String table */
 147         unsigned long   strsize;        /* Size in bytes of string table */
 148 #ifdef __mips__
 149         Elf_Word        local_gotno;    /* Number of local GOT entries */
 150         Elf_Word        symtabno;       /* Number of dynamic symbols */
 151         Elf_Word        gotsym;         /* First dynamic symbol in GOT */
 152 #endif
 153
 154         const Elf_Word *buckets;        /* Hash table buckets array */
 155         unsigned long   nbuckets;       /* Number of buckets */
 156         const Elf_Word *chains;         /* Hash table chain array */
 157         unsigned long   nchains;        /* Number of chains */
 158
 159         Search_Path    *rpaths;         /* Search path specified in object */
 160         Needed_Entry   *needed;         /* Shared objects needed by this (%) */
 161
 162         void            (*init)(void);  /* Initialization function to call */
 163         void            (*fini)(void);  /* Termination function to call */
 164
 165         /* Entry points for dlopen() and friends. */
 166         void           *(*dlopen)(const char *, int);
 167         void           *(*dlsym)(void *, const char *);
 168         char           *(*dlerror)(void);
 169         int             (*dlclose)(void *);
 170         int             (*dladdr)(const void *, Dl_info *);
 171         int             (*dlinfo)(void *, int, void *);
 172
 173         u_int32_t       mainprog:1,     /* True if this is the main program */
 174                         rtld:1,         /* True if this is the dynamic linker */
 175                         textrel:1,      /* True if there are relocations to
 176                                          * text seg */
 177                         symbolic:1,     /* True if generated with
 178                                          * "-Bsymbolic" */
 179                         printed:1,      /* True if ldd has printed it */
 180                         isdynamic:1,    /* True if this is a pure PIC object */
 181                         mainref:1,      /* True if on _rtld_list_main */
 182                         globalref:1,    /* True if on _rtld_list_global */
 183                         init_done:1,    /* True if .init has been added */
 184                         init_called:1,  /* True if .init function has been
 185                                          * called */
 186                         fini_called:1,  /* True if .fini function has been
 187                                          * called */
 188                         initfirst:1;    /* True if object's .init/.fini take
 189                                         * priority over others */
 190
 191         struct link_map linkmap;        /* for GDB */
 192
 193         /* These items are computed by map_object() or by digest_phdr(). */
 194         const char     *interp; /* Pathname of the interpreter, if any */
 195         Objlist         dldags; /* Object belongs to these dlopened DAGs (%) */
 196         Objlist         dagmembers;     /* DAG has these members (%) */
 197         dev_t           dev;            /* Object's filesystem's device */
 198         ino_t           ino;            /* Object's inode number */
 199 } Obj_Entry;
 200
 201 #if defined(_RTLD_SOURCE)
 202
 203 extern struct r_debug _rtld_debug;
 204 extern Search_Path *_rtld_default_paths;
 205 extern Obj_Entry *_rtld_objlist;
 206 extern Obj_Entry **_rtld_objtail;
 207 extern Obj_Entry *_rtld_objmain;
 208 extern Obj_Entry _rtld_objself;
 209 extern Search_Path *_rtld_paths;
 210 extern Library_Xform *_rtld_xforms;
 211 extern bool _rtld_trust;
 212 extern Objlist _rtld_list_global;
 213 extern Objlist _rtld_list_main;
 214 extern Elf_Sym _rtld_sym_zero;
 215
 216 /* rtld.c */
 217
 218 /*
 219  * We export these symbols using _rtld_symbol_lookup and is_exported.
 220  */
 221 char *dlerror(void);
 222 void *dlopen(const char *, int);
 223 void *dlsym(void *, const char *);
 224 int dlclose(void *);
 225 int dladdr(const void *, Dl_info *);
 226 int dlinfo(void *, int, void *);
 227
 228 void _rtld_error(const char *, ...)
 229      __attribute__((__format__(__printf__,1,2)));
 230 void _rtld_die(void) __attribute__((__noreturn__));
 231 void *_rtld_objmain_sym(const char *);
 232 void _rtld_debug_state(void);
 233 void _rtld_linkmap_add(Obj_Entry *);
 234 void _rtld_linkmap_delete(Obj_Entry *);
 235 void _rtld_objlist_push_head(Objlist *, Obj_Entry *);
 236 void _rtld_objlist_push_tail(Objlist *, Obj_Entry *);
 237 Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *);
 238
 239 /* expand.c */
 240 size_t _rtld_expand_path(char *, size_t, const char *, const char *,\
 241     const char *);
 242
 243 /* headers.c */
 244 void _rtld_digest_dynamic(const char *, Obj_Entry *);
 245 Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t);
 246
 247 /* load.c */
 248 Obj_Entry *_rtld_load_object(const char *, int);
 249 int _rtld_load_needed_objects(Obj_Entry *, int);
 250 int _rtld_preload(const char *);
 251
 252 /* path.c */
 253 void _rtld_add_paths(const char *, Search_Path **, const char *);
 254 void _rtld_process_hints(const char *, Search_Path **, Library_Xform **,
 255     const char *);
 256 int _rtld_sysctl(const char *, void *, size_t *);
 257
 258 /* reloc.c */
 259 int _rtld_do_copy_relocations(const Obj_Entry *);
 260 int _rtld_relocate_objects(Obj_Entry *, bool);
 261 int _rtld_relocate_nonplt_objects(const Obj_Entry *);
 262 int _rtld_relocate_plt_lazy(const Obj_Entry *);
 263 int _rtld_relocate_plt_objects(const Obj_Entry *);
 264 void _rtld_setup_pltgot(const Obj_Entry *);
 265
 266 /* search.c */
 267 Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int);
 268
 269 /* symbol.c */
 270 unsigned long _rtld_elf_hash(const char *);
 271 const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long,
 272     const Obj_Entry *, bool);
 273 const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *,
 274     const Obj_Entry **, bool);
 275 const Elf_Sym *_rtld_symlook_list(const char *, unsigned long,
 276     const Objlist *, const Obj_Entry **, bool);
 277 const Elf_Sym *_rtld_symlook_default(const char *, unsigned long,
 278     const Obj_Entry *, const Obj_Entry **, bool);
 279 const Elf_Sym *_rtld_symlook_needed(const char *, unsigned long,
 280     const Needed_Entry *, const Obj_Entry **, bool);
 281
 282 /* map_object.c */
 283 Obj_Entry *_rtld_map_object(const char *, int, const struct stat *);
 284 void _rtld_obj_free(Obj_Entry *);
 285 Obj_Entry *_rtld_obj_new(void);
 286
 287 /* function descriptors */
 288 #ifdef __HAVE_FUNCTION_DESCRIPTORS
 289 Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *,
 290     const Elf_Sym *, Elf_Addr);
 291 const void *_rtld_function_descriptor_function(const void *);
 292 #endif /* __HAVE_FUNCTION_DESCRIPTORS */
 293
 294 #endif /* _RTLD_SOURCE */
 295
 296 #endif /* RTLD_H */