sys/sys/linker.h

   1 /*-
   2  * Copyright (c) 1997 Doug Rabson
   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 AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/sys/linker.h,v 1.17.2.1 2002/03/11 01:13:53 dd Exp $
  27  * $DragonFly: src/sys/sys/linker.h,v 1.11 2008/02/06 22:37:46 nth Exp $
  28  */
  29
  30 #ifndef _SYS_LINKER_H_
  31 #define _SYS_LINKER_H_
  32
  33 #ifndef _SYS_TYPES_H_
  34 #include <sys/types.h>
  35 #endif
  36 #ifndef _SYS_PARAM_H_
  37 #include <sys/param.h>
  38 #endif
  39
  40 #ifdef _KERNEL
  41
  42 #ifndef _SYS_QUEUE_H_
  43 #include <sys/queue.h>
  44 #endif
  45 #ifndef _MACHINE_ELF_H_
  46 #include <machine/elf.h>
  47 #endif
  48
  49 #ifdef MALLOC_DECLARE
  50 MALLOC_DECLARE(M_LINKER);
  51 #endif
  52
  53 /*
  54  * Object representing a file which has been loaded by the linker.
  55  */
  56 typedef struct linker_file* linker_file_t;
  57 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
  58
  59 typedef caddr_t linker_sym_t;           /* opaque symbol */
  60 typedef c_caddr_t c_linker_sym_t;       /* const opaque symbol */
  61
  62 /*
  63  * expanded out linker_sym_t
  64  */
  65 typedef struct linker_symval {
  66     const char*         name;
  67     caddr_t             value;
  68     size_t              size;
  69 } linker_symval_t;
  70
  71 struct linker_file_ops {
  72     /*
  73      * Lookup a symbol in the file's symbol table.  If the symbol is
  74      * not found then return ENOENT, otherwise zero.  If the symbol
  75      * found is a common symbol, return with *address set to zero and
  76      * *size set to the size of the common space required.  Otherwise
  77      * set *address the value of the symbol.
  78      */
  79     int                 (*lookup_symbol)(linker_file_t, const char* name,
  80                                          c_linker_sym_t* sym);
  81
  82     int                 (*symbol_values)(linker_file_t, c_linker_sym_t,
  83                                          linker_symval_t*);
  84
  85     int                 (*search_symbol)(linker_file_t, caddr_t value,
  86                                          c_linker_sym_t* sym, long* diffp);
  87
  88     /*
  89      * Unload a file, releasing dependancies and freeing storage.
  90      */
  91     void                (*unload)(linker_file_t);
  92
  93     int                 (*lookup_set)(linker_file_t, const char *name,
  94                                         void ***firstp, void ***lastp, int *countp);
  95 };
  96
  97 struct common_symbol {
  98     STAILQ_ENTRY(common_symbol) link;
  99     char*               name;
 100     caddr_t             address;
 101 };
 102
 103 struct linker_file {
 104     int                 refs;           /* reference count */
 105     int                 userrefs;       /* kldload(2) count */
 106     int                 flags;
 107 #define LINKER_FILE_LINKED      0x1     /* file has been fully linked */
 108     TAILQ_ENTRY(linker_file) link;      /* list of all loaded files */
 109     char*               filename;       /* file which was loaded */
 110     int                 id;             /* unique id */
 111     caddr_t             address;        /* load address */
 112     size_t              size;           /* size of file */
 113     int                 ndeps;          /* number of dependancies */
 114     linker_file_t*      deps;           /* list of dependancies */
 115     STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
 116     TAILQ_HEAD(, module) modules;       /* modules in this file */
 117     void*               priv;           /* implementation data */
 118
 119     struct linker_file_ops* ops;
 120 };
 121
 122 /*
 123  * Object implementing a class of file (a.out, elf, etc.)
 124  */
 125 typedef struct linker_class *linker_class_t;
 126 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
 127
 128 struct linker_class_ops {
 129     /*
 130      * Load a file, returning the new linker_file_t in *result.  If
 131      * the class does not recognise the file type, zero should be
 132      * returned, without modifying *result.  If the file is
 133      * recognised, the file should be loaded, *result set to the new
 134      * file and zero returned.  If some other error is detected an
 135      * appropriate errno should be returned.
 136      */
 137     int         (*load_file)(const char* filename, linker_file_t* result);
 138 };
 139
 140 struct linker_class {
 141     TAILQ_ENTRY(linker_class) link;     /* list of all file classes */
 142     const char*         desc;           /* description (e.g. "a.out") */
 143     void*               priv;           /* implementation data */
 144
 145     struct linker_class_ops *ops;
 146 };
 147
 148 /*
 149  * The file which is currently loading.  Used to register modules with
 150  * the files which contain them.
 151  */
 152 extern linker_file_t    linker_current_file;
 153
 154 /*
 155  * The "file" for the kernel.
 156  */
 157 extern linker_file_t    linker_kernel_file;
 158
 159 /*
 160  * Add a new file class to the linker.
 161  */
 162 int linker_add_class(const char* _desc, void* _priv,
 163                      struct linker_class_ops* _ops);
 164
 165 /*
 166  * Load a file, trying each file class until one succeeds.
 167  */
 168 int linker_load_file(const char* _filename, linker_file_t* _result);
 169
 170 /*
 171  * Find a currently loaded file given its filename.
 172  */
 173 linker_file_t linker_find_file_by_name(const char* _filename);
 174
 175 /*
 176  * Find a currently loaded file given its file id.
 177  */
 178 linker_file_t linker_find_file_by_id(int _fileid);
 179
 180 /*
 181  * Called from a class handler when a file is laoded.
 182  */
 183 linker_file_t linker_make_file(const char* _filename, void* _priv,
 184                                struct linker_file_ops* _ops);
 185
 186 /*
 187  * Unload a file, freeing up memory.
 188  */
 189 int linker_file_unload(linker_file_t _file);
 190
 191 /*
 192  * Add a dependancy to a file.
 193  */
 194 void linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep);
 195
 196 /*
 197  * Lookup a symbol in a file.  If deps is TRUE, look in dependancies
 198  * if not found in file.  The symbol's value is returned in the
 199  * caddr_t.  An error is returned, 0 if no error occured.
 200  */
 201 int linker_file_lookup_symbol(linker_file_t _file, const char* _name,
 202                             int _deps, caddr_t *);
 203
 204
 205 /*
 206  * Lookup a linker set in a file.  Return pointers to the first entry,
 207  * last + 1, and count of entries.  Use: for (p = start; p < stop; p++) {}
 208  * void *start is really: "struct yoursetmember ***start;"
 209  */
 210 int linker_file_lookup_set(linker_file_t _file, const char *_name,
 211                             void *_start, void *_stop, int *_count);
 212
 213 /*
 214  * Search the linker path for the module.  Return the full pathname in
 215  * a malloc'ed buffer.
 216  */
 217 char *linker_search_path(const char *_filename);
 218
 219 /*
 220  * DDB Helpers, tuned specifically for ddb/db_kld.c
 221  */
 222 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
 223 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
 224                              long *_diffp);
 225 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
 226
 227
 228 #endif  /* _KERNEL */
 229
 230 /*
 231  * Module information subtypes
 232  */
 233 #define MODINFO_END             0x0000          /* End of list */
 234 #define MODINFO_NAME            0x0001          /* Name of module (string) */
 235 #define MODINFO_TYPE            0x0002          /* Type of module (string) */
 236 #define MODINFO_ADDR            0x0003          /* Loaded address */
 237 #define MODINFO_SIZE            0x0004          /* Size of module */
 238 #define MODINFO_EMPTY           0x0005          /* Has been deleted */
 239 #define MODINFO_ARGS            0x0006          /* Parameters string */
 240 #define MODINFO_METADATA        0x8000          /* Module-specfic */
 241
 242 #define MODINFOMD_AOUTEXEC      0x0001          /* a.out exec header */
 243 #define MODINFOMD_ELFHDR        0x0002          /* ELF header */
 244 #define MODINFOMD_SSYM          0x0003          /* start of symbols */
 245 #define MODINFOMD_ESYM          0x0004          /* end of symbols */
 246 #define MODINFOMD_DYNAMIC       0x0005          /* _DYNAMIC pointer */
 247 #define MODINFOMD_ENVP          0x0006          /* (from 5.x) envp[] */
 248 #define MODINFOMD_HOWTO         0x0007          /* (from 5.x) boothowto */
 249 #define MODINFOMD_KERNEND       0x0008          /* (from 5.x) kernend */
 250 #define MODINFOMD_NOCOPY        0x8000          /* don't copy this metadata to the kernel */
 251
 252 #define MODINFOMD_DEPLIST       (0x4001 | MODINFOMD_NOCOPY)     /* depends on */
 253
 254 #ifdef _KERNEL
 255 #define MD_FETCH(mdp, info, type) ({ \
 256         type *__p; \
 257         __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
 258         __p ? *__p : 0; \
 259 })
 260 #endif
 261
 262 #define LINKER_HINTS_VERSION    1               /* linker.hints file version */
 263
 264 #ifdef _KERNEL
 265
 266 /*
 267  * Module lookup
 268  */
 269 extern caddr_t          preload_metadata;
 270 extern caddr_t          preload_search_by_name(const char *);
 271 extern caddr_t          preload_search_by_type(const char *);
 272 extern caddr_t          preload_search_next_name(caddr_t);
 273 extern caddr_t          preload_search_info(caddr_t, int);
 274 extern void             preload_delete_name(const char *);
 275 extern void             preload_bootstrap_relocate(vm_offset_t);
 276 extern struct mod_metadata *find_mod_metadata(const char *);
 277
 278
 279 #ifdef KLD_DEBUG
 280
 281 extern int kld_debug;
 282 #define KLD_DEBUG_FILE  1       /* file load/unload */
 283 #define KLD_DEBUG_SYM   2       /* symbol lookup */
 284
 285 #define KLD_DPF(cat, args)                                      \
 286         do {                                                    \
 287                 if (kld_debug & KLD_DEBUG_##cat) kprintf args;  \
 288         } while (0)
 289
 290 #else
 291
 292 #define KLD_DPF(cat, args)
 293
 294 #endif
 295
 296 /* Support functions */
 297 int     elf_reloc(linker_file_t, const void *, int, const char *);
 298
 299 /* values for type */
 300 #define ELF_RELOC_REL   1
 301 #define ELF_RELOC_RELA  2
 302
 303 #endif /* _KERNEL */
 304
 305 struct kld_file_stat {
 306     int         version;        /* set to sizeof(linker_file_stat) */
 307     char        name[MAXPATHLEN];
 308     int         refs;
 309     int         id;
 310     caddr_t     address;        /* load address */
 311     size_t      size;           /* size in bytes */
 312 };
 313
 314 struct kld_sym_lookup {
 315     int         version;        /* set to sizeof(struct kld_sym_lookup) */
 316     const char  *symname;       /* Symbol name we are looking up */
 317     u_long      symvalue;
 318     size_t      symsize;
 319 };
 320
 321 #define KLDSYM_LOOKUP   1
 322
 323 #ifndef _KERNEL
 324
 325 #ifndef _SYS_CDEFS_H_
 326 #include <sys/cdefs.h>
 327 #endif
 328
 329 __BEGIN_DECLS
 330 int     kldload(const char *);
 331 int     kldunload(int);
 332 int     kldfind(const char *);
 333 int     kldnext(int);
 334 int     kldstat(int, struct kld_file_stat *);
 335 int     kldfirstmod(int);
 336 int     kldsym(int, int, void *);
 337 __END_DECLS
 338
 339 #endif
 340
 341 #endif /* !_SYS_LINKER_H_ */