include/link_aout.h

   1 /*      $OpenBSD: link_aout.h,v 1.2 2004/01/22 21:48:02 espie Exp $     */
   2
   3 /*
   4  * Copyright (c) 1993 Paul Kranenburg
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by Paul Kranenburg.
  18  * 4. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 /*
  34  * RRS section definitions.
  35  *
  36  * The layout of some data structures defined in this header file is
  37  * such that we can provide compatibility with the SunOS 4.x shared
  38  * library scheme.
  39  */
  40
  41 /*
  42  * Symbol description with size. This is simply an `nlist' with
  43  * one field (nz_size) added.
  44  * Used to convey size information on items in the data segment
  45  * of shared objects. An array of these live in the shared object's
  46  * text segment and is addressed by the `sdt_nzlist' field.
  47  */
  48 struct nzlist {
  49         struct nlist    nlist;
  50         unsigned long   nz_size;
  51 #define nz_un           nlist.n_un
  52 #define nz_strx         nlist.n_un.n_strx
  53 #define nz_name         nlist.n_un.n_name
  54 #define nz_type         nlist.n_type
  55 #define nz_value        nlist.n_value
  56 #define nz_desc         nlist.n_desc
  57 #define nz_other        nlist.n_other
  58 };
  59
  60 #define N_AUX(p)        ((p)->n_other & 0xf)
  61 #define N_BIND(p)       (((unsigned int)(p)->n_other >> 4) & 0xf)
  62 #define N_OTHER(r, v)   (((unsigned int)(r) << 4) | ((v) & 0xf))
  63
  64 #define AUX_OBJECT      1
  65 #define AUX_FUNC        2
  66 /*#define BIND_LOCAL    0       not used */
  67 /*#define BIND_GLOBAL   1       not used */
  68 #define BIND_WEAK       2
  69
  70 /*
  71  * The `section_dispatch_table' structure contains offsets to various data
  72  * structures needed to do run-time relocation.
  73  */
  74 struct section_dispatch_table {
  75         struct so_map *sdt_loaded;      /* List of loaded objects */
  76         long    sdt_sods;               /* List of shared objects descriptors */
  77         long    sdt_paths;              /* Library search paths */
  78         long    sdt_got;                /* Global offset table */
  79         long    sdt_plt;                /* Procedure linkage table */
  80         long    sdt_rel;                /* Relocation table */
  81         long    sdt_hash;               /* Symbol hash table */
  82         long    sdt_nzlist;             /* Symbol table itself */
  83         long    sdt_filler2;            /* Unused (was: stab_hash) */
  84         long    sdt_buckets;            /* Number of hash buckets */
  85         long    sdt_strings;            /* Symbol strings */
  86         long    sdt_str_sz;             /* Size of symbol strings */
  87         long    sdt_text_sz;            /* Size of text area */
  88         long    sdt_plt_sz;             /* Size of procedure linkage table */
  89 };
  90
  91 /*
  92  * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table.
  93  * Used to quickly lookup symbols of the shared object by hashing
  94  * on the symbol's name. `rh_symbolnum' is the index of the symbol
  95  * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is
  96  * the next symbol in the hash bucket (in case of collisions).
  97  */
  98 struct rrs_hash {
  99         int     rh_symbolnum;           /* Symbol number */
 100         int     rh_next;                /* Next hash entry */
 101 };
 102
 103 /*
 104  * `rt_symbols' is used to keep track of run-time allocated commons
 105  * and data items copied from shared objects.
 106  */
 107 struct rt_symbol {
 108         struct nzlist           *rt_sp;         /* The symbol */
 109         struct rt_symbol        *rt_next;       /* Next in linear list */
 110         struct rt_symbol        *rt_link;       /* Next in bucket */
 111         caddr_t                 rt_srcaddr;     /* Address of "master" copy */
 112         struct so_map           *rt_smp;        /* Originating map */
 113 };
 114
 115 /*
 116  * Debugger interface structure.
 117  */
 118 struct so_debug {
 119         int     dd_version;             /* Version # of interface */
 120         int     dd_in_debugger;         /* Set when run by debugger */
 121         int     dd_sym_loaded;          /* Run-time linking brought more
 122                                            symbols into scope */
 123         char     *dd_bpt_addr;          /* Address of rtld-generated bpt */
 124         int     dd_bpt_shadow;          /* Original contents of bpt */
 125         struct rt_symbol *dd_cc;        /* Allocated commons/copied data */
 126 };
 127
 128 /*
 129  * Entry points into ld.so - user interface to the run-time linker.
 130  */
 131 struct ld_entry {
 132         void    *(*dlopen)(const char *, int);
 133         int     (*dlclose)(void *);
 134         void    *(*dlsym)(void *, const char *);
 135         int     (*dlctl)(void *, int, void *);
 136         void    (*dlexit)(void);
 137         void    (*dlrsrvd[3])(void);
 138 };
 139
 140 /*
 141  * This is the structure pointed at by the __DYNAMIC symbol if an
 142  * executable requires the attention of the run-time link editor.
 143  * __DYNAMIC is given the value zero if no run-time linking needs to
 144  * be done (it is always present in shared objects).
 145  * The union `d_un' provides for different versions of the dynamic
 146  * linking mechanism (switched on by `d_version'). The last version
 147  * used by Sun is 3. We leave some room here and go to version number
 148  * 8 for NetBSD, the main difference lying in the support for the
 149  * `nz_list' type of symbols.
 150  */
 151
 152 struct  _dynamic {
 153         int             d_version;      /* version # of this interface */
 154         struct so_debug *d_debug;
 155         union {
 156                 struct section_dispatch_table *d_sdt;
 157         } d_un;
 158         struct ld_entry *d_entry;       /* compat - now in crt_ldso */
 159 };
 160
 161 #define LD_VERSION_SUN          (3)
 162 #define LD_VERSION_BSD          (8)
 163 #define LD_VERSION_NZLIST_P(v)  ((v) >= 8)
 164
 165 #define LD_GOT(x)       ((x)->d_un.d_sdt->sdt_got)
 166 #define LD_PLT(x)       ((x)->d_un.d_sdt->sdt_plt)
 167 #define LD_REL(x)       ((x)->d_un.d_sdt->sdt_rel)
 168 #define LD_SYMBOL(x)    ((x)->d_un.d_sdt->sdt_nzlist)
 169 #define LD_HASH(x)      ((x)->d_un.d_sdt->sdt_hash)
 170 #define LD_STRINGS(x)   ((x)->d_un.d_sdt->sdt_strings)
 171 #define LD_NEED(x)      ((x)->d_un.d_sdt->sdt_sods)
 172 #define LD_BUCKETS(x)   ((x)->d_un.d_sdt->sdt_buckets)
 173 #define LD_PATHS(x)     ((x)->d_un.d_sdt->sdt_paths)
 174
 175 #define LD_GOTSZ(x)     ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
 176 #define LD_RELSZ(x)     ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
 177 #define LD_HASHSZ(x)    ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
 178 #define LD_STABSZ(x)    ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
 179 #define LD_PLTSZ(x)     ((x)->d_un.d_sdt->sdt_plt_sz)
 180 #define LD_STRSZ(x)     ((x)->d_un.d_sdt->sdt_str_sz)
 181 #define LD_TEXTSZ(x)    ((x)->d_un.d_sdt->sdt_text_sz)
 182
 183 /*
 184  * Interface to ld.so
 185  */
 186 struct crt_ldso {
 187         int             crt_ba;         /* Base address of ld.so */
 188         int             crt_dzfd;       /* "/dev/zero" file descriptor (SunOS) */
 189         int             crt_ldfd;       /* ld.so file descriptor */
 190         struct _dynamic *crt_dp;        /* Main's __DYNAMIC */
 191         char            **crt_ep;       /* environment strings */
 192         caddr_t         crt_bp;         /* Breakpoint if run from debugger */
 193         char            *crt_prog;      /* Program name (v3) */
 194         char            *crt_ldso;      /* Link editor name (v4) */
 195         struct ld_entry *crt_ldentry;   /* dl*() access (v4) */
 196 };
 197
 198 /*
 199  * Version passed from crt0 to ld.so (1st argument to _rtld()).
 200  */
 201 #define CRT_VERSION_SUN         1
 202 #define CRT_VERSION_BSD_2       2
 203 #define CRT_VERSION_BSD_3       3
 204 #define CRT_VERSION_BSD_4       4