libexec/rtld-elf/rtld.h

   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 1.15.2.6 2003/02/20 20:42:46 kan Exp $
  26  * $DragonFly: src/libexec/rtld-elf/rtld.h,v 1.11 2005/05/11 19:47:06 dillon Exp $
  27  */
  28
  29 #ifndef RTLD_H /* { */
  30 #define RTLD_H 1
  31
  32 #include <machine/elf.h>
  33 #include <sys/types.h>
  34 #include <sys/queue.h>
  35
  36 #include <elf-hints.h>
  37 #include <link.h>
  38 #include <stddef.h>
  39
  40 #include "rtld_machdep.h"
  41
  42 #ifndef STANDARD_LIBRARY_PATH
  43 #define STANDARD_LIBRARY_PATH   "/usr/lib"
  44 #endif
  45
  46 #define NEW(type)       ((type *) xmalloc(sizeof(type)))
  47 #define CNEW(type)      ((type *) xcalloc(sizeof(type)))
  48
  49 /* We might as well do booleans like C++. */
  50 typedef unsigned char bool;
  51 #define false   0
  52 #define true    1
  53
  54 extern size_t tls_last_offset;
  55 extern size_t tls_last_size;
  56 extern size_t tls_static_space;
  57 extern int tls_dtv_generation;
  58 extern int tls_max_index;
  59
  60 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
  61
  62 struct stat;
  63 struct Struct_Obj_Entry;
  64
  65 /* Lists of shared objects */
  66 typedef struct Struct_Objlist_Entry {
  67     STAILQ_ENTRY(Struct_Objlist_Entry) link;
  68     struct Struct_Obj_Entry *obj;
  69 } Objlist_Entry;
  70
  71 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;
  72
  73 /* Types of init and fini functions */
  74 typedef void (*InitFunc)(void);
  75
  76 /* Lists of shared object dependencies */
  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 /* Lock object */
  84 typedef struct Struct_LockInfo {
  85     void *context;              /* Client context for creating locks */
  86     void *thelock;              /* The one big lock */
  87     /* Debugging aids. */
  88     volatile int rcount;        /* Number of readers holding lock */
  89     volatile int wcount;        /* Number of writers holding lock */
  90     /* Methods */
  91     void *(*lock_create)(void *context);
  92     void (*rlock_acquire)(void *lock);
  93     void (*wlock_acquire)(void *lock);
  94     void (*rlock_release)(void *lock);
  95     void (*wlock_release)(void *lock);
  96     void (*lock_destroy)(void *lock);
  97     void (*context_destroy)(void *context);
  98 } LockInfo;
  99
 100 /*
 101  * Shared object descriptor.
 102  *
 103  * Items marked with "(%)" are dynamically allocated, and must be freed
 104  * when the structure is destroyed.
 105  *
 106  * CAUTION: It appears that the JDK port peeks into these structures.
 107  * It looks at "next" and "mapbase" at least.  Don't add new members
 108  * near the front, until this can be straightened out.
 109  */
 110 typedef struct Struct_Obj_Entry {
 111     /*
 112      * These two items have to be set right for compatibility with the
 113      * original ElfKit crt1.o.
 114      */
 115     Elf_Word magic;             /* Magic number (sanity check) */
 116     Elf_Word version;           /* Version number of struct format */
 117
 118     struct Struct_Obj_Entry *next;
 119     char *path;                 /* Pathname of underlying file (%) */
 120     char *origin_path;          /* Directory path of origin file */
 121     int refcount;
 122     int dl_refcount;            /* Number of times loaded by dlopen */
 123
 124     /* These items are computed by map_object() or by digest_phdr(). */
 125     caddr_t mapbase;            /* Base address of mapped region */
 126     size_t mapsize;             /* Size of mapped region in bytes */
 127     size_t textsize;            /* Size of text segment in bytes */
 128     Elf_Addr vaddrbase;         /* Base address in shared object file */
 129     caddr_t relocbase;          /* Relocation constant = mapbase - vaddrbase */
 130     const Elf_Dyn *dynamic;     /* Dynamic section */
 131     caddr_t entry;              /* Entry point */
 132     const Elf_Phdr *phdr;       /* Program header if it is mapped, else NULL */
 133     size_t phsize;              /* Size of program header in bytes */
 134     const char *interp;         /* Pathname of the interpreter, if any */
 135
 136     /* TLS information */
 137     int tlsindex;               /* Index in DTV for this module */
 138     void *tlsinit;              /* Base address of TLS init block */
 139     size_t tlsinitsize;         /* Size of TLS init block for this module */
 140     size_t tlssize;             /* Size of TLS block for this module */
 141     size_t tlsoffset;           /* Offset of static TLS block for this module */
 142     size_t tlsalign;            /* Alignment of static TLS block */
 143
 144     /* Items from the dynamic section. */
 145     Elf_Addr *pltgot;           /* PLT or GOT, depending on architecture */
 146     const Elf_Rel *rel;         /* Relocation entries */
 147     unsigned long relsize;      /* Size in bytes of relocation info */
 148     const Elf_Rela *rela;       /* Relocation entries with addend */
 149     unsigned long relasize;     /* Size in bytes of addend relocation info */
 150     const Elf_Rel *pltrel;      /* PLT relocation entries */
 151     unsigned long pltrelsize;   /* Size in bytes of PLT relocation info */
 152     const Elf_Rela *pltrela;    /* PLT relocation entries with addend */
 153     unsigned long pltrelasize;  /* Size in bytes of PLT addend reloc info */
 154     const Elf_Sym *symtab;      /* Symbol table */
 155     const char *strtab;         /* String table */
 156     unsigned long strsize;      /* Size in bytes of string table */
 157
 158     const Elf_Addr *buckets;    /* Hash table buckets array */
 159     unsigned long nbuckets;     /* Number of buckets */
 160     const Elf_Addr *chains;     /* Hash table chain array */
 161     unsigned long nchains;      /* Number of chains */
 162
 163     const char *rpath;          /* Search path specified in object */
 164     Needed_Entry *needed;       /* Shared objects needed by this one (%) */
 165
 166     InitFunc init;              /* Initialization function to call */
 167     InitFunc fini;              /* Termination function to call */
 168
 169     bool mainprog;              /* True if this is the main program */
 170     bool rtld;                  /* True if this is the dynamic linker */
 171     bool textrel;               /* True if there are relocations to text seg */
 172     bool symbolic;              /* True if generated with "-Bsymbolic" */
 173     bool bind_now;              /* True if all relocations should be made first */
 174     bool traced;                /* Already printed in ldd trace output */
 175     bool jmpslots_done;         /* Already have relocated the jump slots */
 176     bool init_done;             /* Already have added object to init list */
 177     bool tls_done;              /* Already allocated offset for static TLS */
 178
 179     struct link_map linkmap;    /* for GDB and dlinfo() */
 180     Objlist dldags;             /* Object belongs to these dlopened DAGs (%) */
 181     Objlist dagmembers;         /* DAG has these members (%) */
 182     dev_t dev;                  /* Object's filesystem's device */
 183     ino_t ino;                  /* Object's inode number */
 184 } Obj_Entry;
 185
 186 #define RTLD_MAGIC      0xd550b87a
 187 #define RTLD_VERSION    1
 188
 189 /*
 190  * Symbol cache entry used during relocation to avoid multiple lookups
 191  * of the same symbol.
 192  */
 193 typedef struct Struct_SymCache {
 194     const Elf_Sym *sym;         /* Symbol table entry */
 195     const Obj_Entry *obj;       /* Shared object which defines it */
 196 } SymCache;
 197
 198 void             _rtld_error(const char *, ...) __printflike(1, 2);
 199 Obj_Entry       *map_object(int, const char *, const struct stat *);
 200 void            *xcalloc(size_t);
 201 void            *xmalloc(size_t);
 202 void            *xrealloc(void *, size_t);
 203 char            *xstrdup(const char *);
 204
 205 void             dump_relocations(Obj_Entry *);
 206 void             dump_obj_relocations(Obj_Entry *);
 207 void             dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long);
 208 void             dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long);
 209
 210 /*
 211  * Function declarations.
 212  */
 213 const char      *basename(const char *);
 214 int              do_copy_relocations(Obj_Entry *);
 215 unsigned long    elf_hash(const char *);
 216 const Elf_Sym    *find_symdef(unsigned long, const Obj_Entry *,
 217                               const Obj_Entry **, bool, SymCache *);
 218 void             init_pltgot(Obj_Entry *);
 219 void             lockdflt_init(LockInfo *);
 220 void             obj_free(Obj_Entry *);
 221 Obj_Entry       *obj_new(void);
 222 int              reloc_non_plt(Obj_Entry *, Obj_Entry *);
 223 int              reloc_plt(Obj_Entry *);
 224 int              reloc_jmpslots(Obj_Entry *);
 225 void             _rtld_bind_start(void);
 226 const Elf_Sym   *symlook_obj(const char *, unsigned long, const Obj_Entry *,
 227                              bool);
 228
 229 void            *tls_get_addr_common(void **, int, size_t);
 230 struct tls_tcb  *allocate_tls(Obj_Entry *);
 231 void             free_tls(struct tls_tcb *);
 232 void             *allocate_module_tls(int);
 233 bool             allocate_tls_offset(Obj_Entry *);
 234 void             free_tls_offset(Obj_Entry *);
 235 void             allocate_initial_tls(Obj_Entry *);
 236 #endif /* } */