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 1.7 2005/02/28 16:23:55 joerg Exp $
  28  */
  29
  30 #ifndef _SYS_LINKER_H_
  31 #define _SYS_LINKER_H_
  32
  33 #ifdef _KERNEL
  34
  35 #include <machine/elf.h>
  36
  37 #ifdef MALLOC_DECLARE
  38 MALLOC_DECLARE(M_LINKER);
  39 #endif
  40
  41 /*
  42  * Object representing a file which has been loaded by the linker.
  43  */
  44 typedef struct linker_file* linker_file_t;
  45 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
  46
  47 typedef caddr_t linker_sym_t;           /* opaque symbol */
  48 typedef c_caddr_t c_linker_sym_t;       /* const opaque symbol */
  49
  50 /*
  51  * expanded out linker_sym_t
  52  */
  53 typedef struct linker_symval {
  54     const char*         name;
  55     caddr_t             value;
  56     size_t              size;
  57 } linker_symval_t;
  58
  59 struct linker_file_ops {
  60     /*
  61      * Lookup a symbol in the file's symbol table.  If the symbol is
  62      * not found then return ENOENT, otherwise zero.  If the symbol
  63      * found is a common symbol, return with *address set to zero and
  64      * *size set to the size of the common space required.  Otherwise
  65      * set *address the value of the symbol.
  66      */
  67     int                 (*lookup_symbol)(linker_file_t, const char* name,
  68                                          c_linker_sym_t* sym);
  69
  70     int                 (*symbol_values)(linker_file_t, c_linker_sym_t,
  71                                          linker_symval_t*);
  72
  73     int                 (*search_symbol)(linker_file_t, caddr_t value,
  74                                          c_linker_sym_t* sym, long* diffp);
  75
  76     /*
  77      * Unload a file, releasing dependancies and freeing storage.
  78      */
  79     void                (*unload)(linker_file_t);
  80
  81     int                 (*lookup_set)(linker_file_t, const char *name,
  82                                         void ***firstp, void ***lastp, int *countp);
  83 };
  84
  85 struct common_symbol {
  86     STAILQ_ENTRY(common_symbol) link;
  87     char*               name;
  88     caddr_t             address;
  89 };
  90
  91 struct linker_file {
  92     int                 refs;           /* reference count */
  93     int                 userrefs;       /* kldload(2) count */
  94     int                 flags;
  95 #define LINKER_FILE_LINKED      0x1     /* file has been fully linked */
  96     TAILQ_ENTRY(linker_file) link;      /* list of all loaded files */
  97     char*               filename;       /* file which was loaded */
  98     int                 id;             /* unique id */
  99     caddr_t             address;        /* load address */
 100     size_t              size;           /* size of file */
 101     int                 ndeps;          /* number of dependancies */
 102     linker_file_t*      deps;           /* list of dependancies */
 103     STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
 104     TAILQ_HEAD(, module) modules;       /* modules in this file */
 105     void*               priv;           /* implementation data */
 106
 107     struct linker_file_ops* ops;
 108 };
 109
 110 /*
 111  * Object implementing a class of file (a.out, elf, etc.)
 112  */
 113 typedef struct linker_class *linker_class_t;
 114 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
 115
 116 struct linker_class_ops {
 117     /*
 118      * Load a file, returning the new linker_file_t in *result.  If
 119      * the class does not recognise the file type, zero should be
 120      * returned, without modifying *result.  If the file is
 121      * recognised, the file should be loaded, *result set to the new
 122      * file and zero returned.  If some other error is detected an
 123      * appropriate errno should be returned.
 124      */
 125     int         (*load_file)(const char* filename, linker_file_t* result);
 126 };
 127
 128 struct linker_class {
 129     TAILQ_ENTRY(linker_class) link;     /* list of all file classes */
 130     const char*         desc;           /* description (e.g. "a.out") */
 131     void*               priv;           /* implementation data */
 132
 133     struct linker_class_ops *ops;
 134 };
 135
 136 /*
 137  * The file which is currently loading.  Used to register modules with
 138  * the files which contain them.
 139  */
 140 extern linker_file_t    linker_current_file;
 141
 142 /*
 143  * The "file" for the kernel.
 144  */
 145 extern linker_file_t    linker_kernel_file;
 146
 147 /*
 148  * Add a new file class to the linker.
 149  */
 150 int linker_add_class(const char* _desc, void* _priv,
 151                      struct linker_class_ops* _ops);
 152
 153 /*
 154  * Load a file, trying each file class until one succeeds.
 155  */
 156 int linker_load_file(const char* _filename, linker_file_t* _result);
 157
 158 /*
 159  * Find a currently loaded file given its filename.
 160  */
 161 linker_file_t linker_find_file_by_name(const char* _filename);
 162
 163 /*
 164  * Find a currently loaded file given its file id.
 165  */
 166 linker_file_t linker_find_file_by_id(int _fileid);
 167
 168 /*
 169  * Called from a class handler when a file is laoded.
 170  */
 171 linker_file_t linker_make_file(const char* _filename, void* _priv,
 172                                struct linker_file_ops* _ops);
 173
 174 /*
 175  * Unload a file, freeing up memory.
 176  */
 177 int linker_file_unload(linker_file_t _file);
 178
 179 /*
 180  * Add a dependancy to a file.
 181  */
 182 int linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep);
 183
 184 /*
 185  * Lookup a symbol in a file.  If deps is TRUE, look in dependancies
 186  * if not found in file.  The symbol's value is returned in the
 187  * caddr_t.  An error is returned, 0 if no error occured.
 188  */
 189 int linker_file_lookup_symbol(linker_file_t _file, const char* _name,
 190                             int _deps, caddr_t *);
 191
 192
 193 /*
 194  * Lookup a linker set in a file.  Return pointers to the first entry,
 195  * last + 1, and count of entries.  Use: for (p = start; p < stop; p++) {}
 196  * void *start is really: "struct yoursetmember ***start;"
 197  */
 198 int linker_file_lookup_set(linker_file_t _file, const char *_name,
 199                             void *_start, void *_stop, int *_count);
 200
 201 /*
 202  * Search the linker path for the module.  Return the full pathname in
 203  * a malloc'ed buffer.
 204  */
 205 char *linker_search_path(const char *_filename);
 206
 207 /*
 208  * DDB Helpers, tuned specifically for ddb/db_kld.c
 209  */
 210 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
 211 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
 212                              long *_diffp);
 213 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
 214
 215
 216 #endif  /* _KERNEL */
 217
 218 /*
 219  * Module information subtypes
 220  */
 221 #define MODINFO_END             0x0000          /* End of list */
 222 #define MODINFO_NAME            0x0001          /* Name of module (string) */
 223 #define MODINFO_TYPE            0x0002          /* Type of module (string) */
 224 #define MODINFO_ADDR            0x0003          /* Loaded address */
 225 #define MODINFO_SIZE            0x0004          /* Size of module */
 226 #define MODINFO_EMPTY           0x0005          /* Has been deleted */
 227 #define MODINFO_ARGS            0x0006          /* Parameters string */
 228 #define MODINFO_METADATA        0x8000          /* Module-specfic */
 229
 230 #define MODINFOMD_AOUTEXEC      0x0001          /* a.out exec header */
 231 #define MODINFOMD_ELFHDR        0x0002          /* ELF header */
 232 #define MODINFOMD_SSYM          0x0003          /* start of symbols */
 233 #define MODINFOMD_ESYM          0x0004          /* end of symbols */
 234 #define MODINFOMD_DYNAMIC       0x0005          /* _DYNAMIC pointer */
 235 #define MODINFOMD_ENVP          0x0006          /* (from 5.x) envp[] */
 236 #define MODINFOMD_HOWTO         0x0007          /* (from 5.x) boothowto */
 237 #define MODINFOMD_KERNEND       0x0008          /* (from 5.x) kernend */
 238 #define MODINFOMD_NOCOPY        0x8000          /* don't copy this metadata to the kernel */
 239
 240 #define MODINFOMD_DEPLIST       (0x4001 | MODINFOMD_NOCOPY)     /* depends on */
 241
 242 #ifdef _KERNEL
 243 #define MD_FETCH(mdp, info, type) ({ \
 244         type *__p; \
 245         __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
 246         __p ? *__p : 0; \
 247 })
 248 #endif
 249
 250 #define LINKER_HINTS_VERSION    1               /* linker.hints file version */
 251
 252 #ifdef _KERNEL
 253
 254 /*
 255  * Module lookup
 256  */
 257 extern caddr_t          preload_metadata;
 258 extern caddr_t          preload_search_by_name(const char *);
 259 extern caddr_t          preload_search_by_type(const char *);
 260 extern caddr_t          preload_search_next_name(caddr_t);
 261 extern caddr_t          preload_search_info(caddr_t, int);
 262 extern void             preload_delete_name(const char *);
 263 extern void             preload_bootstrap_relocate(vm_offset_t);
 264 extern struct mod_metadata *find_mod_metadata(const char *);
 265
 266
 267 #ifdef KLD_DEBUG
 268
 269 extern int kld_debug;
 270 #define KLD_DEBUG_FILE  1       /* file load/unload */
 271 #define KLD_DEBUG_SYM   2       /* symbol lookup */
 272
 273 #define KLD_DPF(cat, args)                                      \
 274         do {                                                    \
 275                 if (kld_debug & KLD_DEBUG_##cat) printf args;   \
 276         } while (0)
 277
 278 #else
 279
 280 #define KLD_DPF(cat, args)
 281
 282 #endif
 283
 284 /* Support functions */
 285 int     elf_reloc(linker_file_t, const void *, int, const char *);
 286
 287 /* values for type */
 288 #define ELF_RELOC_REL   1
 289 #define ELF_RELOC_RELA  2
 290
 291 #endif /* _KERNEL */
 292
 293 struct kld_file_stat {
 294     int         version;        /* set to sizeof(linker_file_stat) */
 295     char        name[MAXPATHLEN];
 296     int         refs;
 297     int         id;
 298     caddr_t     address;        /* load address */
 299     size_t      size;           /* size in bytes */
 300 };
 301
 302 struct kld_sym_lookup {
 303     int         version;        /* set to sizeof(struct kld_sym_lookup) */
 304     const char  *symname;       /* Symbol name we are looking up */
 305     u_long      symvalue;
 306     size_t      symsize;
 307 };
 308 #define KLDSYM_LOOKUP   1
 309
 310 #ifndef _KERNEL
 311
 312 #include <sys/cdefs.h>
 313
 314 __BEGIN_DECLS
 315 int     kldload(const char *);
 316 int     kldunload(int);
 317 int     kldfind(const char *);
 318 int     kldnext(int);
 319 int     kldstat(int, struct kld_file_stat *);
 320 int     kldfirstmod(int);
 321 int     kldsym(int, int, void *);
 322 __END_DECLS
 323
 324 #endif
 325
 326 #endif /* !_SYS_LINKER_H_ */