libiberty/simple-object-common.h

   1 /* simple-object-common.h -- common structs for object file manipulation.
   2    Copyright (C) 2010-2020 Free Software Foundation, Inc.
   3
   4 This file is part of the libiberty library.
   5 Libiberty is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public
   7 License as published by the Free Software Foundation; either
   8 version 2 of the License, or (at your option) any later version.
   9
  10 Libiberty is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with libiberty; see the file COPYING.LIB.  If not,
  17 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  18 Boston, MA 02110-1301, USA.  */
  19
  20 /* Forward reference.  */
  21 struct simple_object_functions;
  22
  23 /* An object file opened for reading.  */
  24
  25 struct simple_object_read_struct
  26 {
  27   /* The file descriptor.  */
  28   int descriptor;
  29   /* The offset within the file.  */
  30   off_t offset;
  31   /* The functions which do the actual work.  */
  32   const struct simple_object_functions *functions;
  33   /* Private data for the object file format.  */
  34   void *data;
  35 };
  36
  37 /* Object file attributes.  */
  38
  39 struct simple_object_attributes_struct
  40 {
  41   /* The functions which do the actual work.  */
  42   const struct simple_object_functions *functions;
  43   /* Private data for the object file format.  */
  44   void *data;
  45 };
  46
  47 /* An object file being created.  */
  48
  49 struct simple_object_write_struct
  50 {
  51   /* The functions which do the actual work.  */
  52   const struct simple_object_functions *functions;
  53   /* The segment_name argument from the user.  */
  54   char *segment_name;
  55   /* The start of the list of sections.  */
  56   simple_object_write_section *sections;
  57   /* The last entry in the list of sections.  */
  58   simple_object_write_section *last_section;
  59   /* Private data for the object file format.  */
  60   void *data;
  61 };
  62
  63 /* A section in an object file being created.  */
  64
  65 struct simple_object_write_section_struct
  66 {
  67   /* Next in the list of sections attached to an
  68      simple_object_write.  */
  69   simple_object_write_section *next;
  70   /* The name of this section.  */
  71   char *name;
  72   /* The required alignment.  */
  73   unsigned int align;
  74   /* The first data attached to this section.  */
  75   struct simple_object_write_section_buffer *buffers;
  76   /* The last data attached to this section.  */
  77   struct simple_object_write_section_buffer *last_buffer;
  78 };
  79
  80 /* Data attached to a section.  */
  81
  82 struct simple_object_write_section_buffer
  83 {
  84   /* The next data for this section.  */
  85   struct simple_object_write_section_buffer *next;
  86   /* The size of the buffer.  */
  87   size_t size;
  88   /* The actual bytes.  */
  89   const void *buffer;
  90   /* A buffer to free, or NULL.  */
  91   void *free_buffer;
  92 };
  93
  94 /* The number of bytes we read from the start of the file to pass to
  95    the match function.  */
  96 #define SIMPLE_OBJECT_MATCH_HEADER_LEN (16)
  97
  98 /* Format-specific object file functions.  */
  99
 100 struct simple_object_functions
 101 {
 102   /* If this file matches these functions, return a new value for the
 103      private data for an simple_object_read.  HEADER is the first 16
 104      bytes of the file.  DESCRIPTOR, OFFSET, SEGMENT_NAME, ERRMSG, and
 105      ERR are as for simple_object_open_read.  If this file does not
 106      match, this function should return NULL with *ERRMSG set to
 107      NULL.  */
 108   void *(*match) (unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN],
 109                   int descriptor, off_t offset, const char *segment_name,
 110                   const char **errmsg, int *err);
 111
 112   /* Implement simple_object_find_sections.  */
 113   const char *(*find_sections) (simple_object_read *,
 114                                 int (*pfn) (void *, const char *,
 115                                             off_t offset, off_t length),
 116                                 void *data,
 117                                 int *err);
 118
 119   /* Return the private data for the attributes for SOBJ.  */
 120   void *(*fetch_attributes) (simple_object_read *sobj, const char **errmsg,
 121                              int *err);
 122
 123   /* Release the private data for an simple_object_read.  */
 124   void (*release_read) (void *);
 125
 126   /* Merge the private data for the attributes of two files.  If they
 127      could be linked together, return NULL.  Otherwise return an error
 128      message.  */
 129   const char *(*attributes_merge) (void *, void *, int *err);
 130
 131   /* Release the private data for an simple_object_attributes.  */
 132   void (*release_attributes) (void *);
 133
 134   /* Start creating an object file.  */
 135   void *(*start_write) (void *attributes_data, const char **errmsg,
 136                         int *err);
 137
 138   /* Write the complete object file.  */
 139   const char *(*write_to_file) (simple_object_write *sobj, int descriptor,
 140                                 int *err);
 141
 142   /* Release the private data for an simple_object_write.  */
 143   void (*release_write) (void *);
 144
 145   /* Copy LTO debug sections.  */
 146   const char *(*copy_lto_debug_sections) (simple_object_read *sobj,
 147                                           simple_object_write *dobj,
 148                                           char *(*pfn) (const char *),
 149                                           int *err);
 150 };
 151
 152 /* The known object file formats.  */
 153
 154 extern const struct simple_object_functions simple_object_coff_functions;
 155 extern const struct simple_object_functions simple_object_elf_functions;
 156 extern const struct simple_object_functions simple_object_mach_o_functions;
 157 extern const struct simple_object_functions simple_object_xcoff_functions;
 158
 159 /* Read SIZE bytes from DESCRIPTOR at file offset OFFSET into BUFFER.
 160    Return non-zero on success.  On failure return 0 and set *ERRMSG
 161    and *ERR.  */
 162
 163 extern int
 164 simple_object_internal_read (int descriptor, off_t offset,
 165                              unsigned char *buffer, size_t size,
 166                              const char **errmsg, int *err);
 167
 168 /* Write SIZE bytes from BUFFER to DESCRIPTOR at file offset OFFSET.
 169    Return non-zero on success.  On failure return 0 and set *ERRMSG
 170    and *ERR.  */
 171
 172 extern int
 173 simple_object_internal_write (int descriptor, off_t offset,
 174                               const unsigned char *buffer, size_t size,
 175                               const char **errmsg, int *err);
 176
 177 /* Define ulong_type as an unsigned 64-bit type if available.
 178    Otherwise just make it unsigned long.  */
 179
 180 #ifdef UNSIGNED_64BIT_TYPE
 181 __extension__ typedef UNSIGNED_64BIT_TYPE ulong_type;
 182 #else
 183 typedef unsigned long ulong_type;
 184 #endif
 185
 186 /* Fetch a big-endian 16-bit value.  */
 187
 188 static inline unsigned short
 189 simple_object_fetch_big_16 (const unsigned char *buf)
 190 {
 191   return ((unsigned short) buf[0] << 8) | (unsigned short) buf[1];
 192 }
 193
 194 /* Fetch a little-endian 16-bit value.  */
 195
 196 static inline unsigned short
 197 simple_object_fetch_little_16 (const unsigned char *buf)
 198 {
 199   return ((unsigned short) buf[1] << 8) | (unsigned short) buf[0];
 200 }
 201
 202 /* Fetch a big-endian 32-bit value.  */
 203
 204 static inline unsigned int
 205 simple_object_fetch_big_32 (const unsigned char *buf)
 206 {
 207   return (((unsigned int) buf[0] << 24)
 208           | ((unsigned int) buf[1] << 16)
 209           | ((unsigned int) buf[2] << 8)
 210           | (unsigned int) buf[3]);
 211 }
 212
 213 /* Fetch a little-endian 32-bit value.  */
 214
 215 static inline unsigned int
 216 simple_object_fetch_little_32 (const unsigned char *buf)
 217 {
 218   return (((unsigned int) buf[3] << 24)
 219           | ((unsigned int) buf[2] << 16)
 220           | ((unsigned int) buf[1] << 8)
 221           | (unsigned int) buf[0]);
 222 }
 223
 224 /* Fetch a big-endian 32-bit value as a ulong_type.  */
 225
 226 static inline ulong_type
 227 simple_object_fetch_big_32_ulong (const unsigned char *buf)
 228 {
 229   return (ulong_type) simple_object_fetch_big_32 (buf);
 230 }
 231
 232 /* Fetch a little-endian 32-bit value as a ulong_type.  */
 233
 234 static inline ulong_type
 235 simple_object_fetch_little_32_ulong (const unsigned char *buf)
 236 {
 237   return (ulong_type) simple_object_fetch_little_32 (buf);
 238 }
 239
 240 #ifdef UNSIGNED_64BIT_TYPE
 241
 242 /* Fetch a big-endian 64-bit value.  */
 243
 244 static inline ulong_type
 245 simple_object_fetch_big_64 (const unsigned char *buf)
 246 {
 247   return (((ulong_type) buf[0] << 56)
 248           | ((ulong_type) buf[1] << 48)
 249           | ((ulong_type) buf[2] << 40)
 250           | ((ulong_type) buf[3] << 32)
 251           | ((ulong_type) buf[4] << 24)
 252           | ((ulong_type) buf[5] << 16)
 253           | ((ulong_type) buf[6] << 8)
 254           | (ulong_type) buf[7]);
 255 }
 256
 257 /* Fetch a little-endian 64-bit value.  */
 258
 259 static inline ulong_type
 260 simple_object_fetch_little_64 (const unsigned char *buf)
 261 {
 262   return (((ulong_type) buf[7] << 56)
 263           | ((ulong_type) buf[6] << 48)
 264           | ((ulong_type) buf[5] << 40)
 265           | ((ulong_type) buf[4] << 32)
 266           | ((ulong_type) buf[3] << 24)
 267           | ((ulong_type) buf[2] << 16)
 268           | ((ulong_type) buf[1] << 8)
 269           | (ulong_type) buf[0]);
 270 }
 271
 272 #endif
 273
 274 /* Store a big-endian 16-bit value.  */
 275
 276 static inline void
 277 simple_object_set_big_16 (unsigned char *buf, unsigned short val)
 278 {
 279   buf[0] = (val >> 8) & 0xff;
 280   buf[1] = val & 0xff;
 281 }
 282
 283 /* Store a little-endian 16-bit value.  */
 284
 285 static inline void
 286 simple_object_set_little_16 (unsigned char *buf, unsigned short val)
 287 {
 288   buf[1] = (val >> 8) & 0xff;
 289   buf[0] = val & 0xff;
 290 }
 291
 292 /* Store a big-endian 32-bit value.  */
 293
 294 static inline void
 295 simple_object_set_big_32 (unsigned char *buf, unsigned int val)
 296 {
 297   buf[0] = (val >> 24) & 0xff;
 298   buf[1] = (val >> 16) & 0xff;
 299   buf[2] = (val >> 8) & 0xff;
 300   buf[3] = val & 0xff;
 301 }
 302
 303 /* Store a little-endian 32-bit value.  */
 304
 305 static inline void
 306 simple_object_set_little_32 (unsigned char *buf, unsigned int val)
 307 {
 308   buf[3] = (val >> 24) & 0xff;
 309   buf[2] = (val >> 16) & 0xff;
 310   buf[1] = (val >> 8) & 0xff;
 311   buf[0] = val & 0xff;
 312 }
 313
 314 /* Store a big-endian 32-bit value coming in as a ulong_type.  */
 315
 316 static inline void
 317 simple_object_set_big_32_ulong (unsigned char *buf, ulong_type val)
 318 {
 319   simple_object_set_big_32 (buf, val);
 320 }
 321
 322 /* Store a little-endian 32-bit value coming in as a ulong_type.  */
 323
 324 static inline void
 325 simple_object_set_little_32_ulong (unsigned char *buf, ulong_type val)
 326 {
 327   simple_object_set_little_32 (buf, val);
 328 }
 329
 330 #ifdef UNSIGNED_64BIT_TYPE
 331
 332 /* Store a big-endian 64-bit value.  */
 333
 334 static inline void
 335 simple_object_set_big_64 (unsigned char *buf, ulong_type val)
 336 {
 337   buf[0] = (val >> 56) & 0xff;
 338   buf[1] = (val >> 48) & 0xff;
 339   buf[2] = (val >> 40) & 0xff;
 340   buf[3] = (val >> 32) & 0xff;
 341   buf[4] = (val >> 24) & 0xff;
 342   buf[5] = (val >> 16) & 0xff;
 343   buf[6] = (val >> 8) & 0xff;
 344   buf[7] = val & 0xff;
 345 }
 346
 347 /* Store a little-endian 64-bit value.  */
 348
 349 static inline void
 350 simple_object_set_little_64 (unsigned char *buf, ulong_type val)
 351 {
 352   buf[7] = (val >> 56) & 0xff;
 353   buf[6] = (val >> 48) & 0xff;
 354   buf[5] = (val >> 40) & 0xff;
 355   buf[4] = (val >> 32) & 0xff;
 356   buf[3] = (val >> 24) & 0xff;
 357   buf[2] = (val >> 16) & 0xff;
 358   buf[1] = (val >> 8) & 0xff;
 359   buf[0] = val & 0xff;
 360 }
 361
 362 #endif