libiberty/simple-object.c

   1 /* simple-object.c -- simple routines to read and write object files.
   2    Copyright 2010 Free Software Foundation, Inc.
   3    Written by Ian Lance Taylor, Google.
   4
   5 This program is free software; you can redistribute it and/or modify it
   6 under the terms of the GNU General Public License as published by the
   7 Free Software Foundation; either version 2, or (at your option) any
   8 later version.
   9
  10 This program 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
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, 51 Franklin Street - Fifth Floor,
  18 Boston, MA 02110-1301, USA.  */
  19
  20 #include "config.h"
  21 #include "libiberty.h"
  22 #include "simple-object.h"
  23
  24 #include <errno.h>
  25
  26 #ifdef HAVE_STDLIB_H
  27 #include <stdlib.h>
  28 #endif
  29
  30 #ifdef HAVE_STDINT_H
  31 #include <stdint.h>
  32 #endif
  33
  34 #ifdef HAVE_STRING_H
  35 #include <string.h>
  36 #endif
  37
  38 #ifdef HAVE_INTTYPES_H
  39 #include <inttypes.h>
  40 #endif
  41
  42 #ifndef SEEK_SET
  43 #define SEEK_SET 0
  44 #endif
  45
  46 #include "simple-object-common.h"
  47
  48 /* The known object file formats.  */
  49
  50 static const struct simple_object_functions * const format_functions[] =
  51 {
  52   &simple_object_elf_functions,
  53   &simple_object_mach_o_functions,
  54   &simple_object_coff_functions,
  55   &simple_object_xcoff_functions
  56 };
  57
  58 /* Read data from a file using the simple_object error reporting
  59    conventions.  */
  60
  61 int
  62 simple_object_internal_read (int descriptor, off_t offset,
  63                              unsigned char *buffer, size_t size,
  64                              const char **errmsg, int *err)
  65 {
  66   if (lseek (descriptor, offset, SEEK_SET) < 0)
  67     {
  68       *errmsg = "lseek";
  69       *err = errno;
  70       return 0;
  71     }
  72
  73   do
  74     {
  75       ssize_t got = read (descriptor, buffer, size);
  76       if (got == 0)
  77         break;
  78       else if (got > 0)
  79         {
  80           buffer += got;
  81           size -= got;
  82         }
  83       else if (errno != EINTR)
  84         {
  85           *errmsg = "read";
  86           *err = errno;
  87           return 0;
  88         }
  89     }
  90   while (size > 0);
  91
  92   if (size > 0)
  93     {
  94       *errmsg = "file too short";
  95       *err = 0;
  96       return 0;
  97     }
  98
  99   return 1;
 100 }
 101
 102 /* Write data to a file using the simple_object error reporting
 103    conventions.  */
 104
 105 int
 106 simple_object_internal_write (int descriptor, off_t offset,
 107                               const unsigned char *buffer, size_t size,
 108                               const char **errmsg, int *err)
 109 {
 110   ssize_t wrote;
 111
 112   if (lseek (descriptor, offset, SEEK_SET) < 0)
 113     {
 114       *errmsg = "lseek";
 115       *err = errno;
 116       return 0;
 117     }
 118
 119   wrote = write (descriptor, buffer, size);
 120   if (wrote < 0)
 121     {
 122       *errmsg = "write";
 123       *err = errno;
 124       return 0;
 125     }
 126
 127   if ((size_t) wrote < size)
 128     {
 129       *errmsg = "short write";
 130       *err = 0;
 131       return 0;
 132     }
 133
 134   return 1;
 135 }
 136
 137 /* Open for read.  */
 138
 139 simple_object_read *
 140 simple_object_start_read (int descriptor, off_t offset,
 141                           const char *segment_name, const char **errmsg,
 142                           int *err)
 143 {
 144   unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN];
 145   size_t len, i;
 146
 147   if (!simple_object_internal_read (descriptor, offset, header,
 148                                     SIMPLE_OBJECT_MATCH_HEADER_LEN,
 149                                     errmsg, err))
 150     return NULL;
 151
 152   len = sizeof (format_functions) / sizeof (format_functions[0]);
 153   for (i = 0; i < len; ++i)
 154     {
 155       void *data;
 156
 157       data = format_functions[i]->match (header, descriptor, offset,
 158                                          segment_name, errmsg, err);
 159       if (data != NULL)
 160         {
 161           simple_object_read *ret;
 162
 163           ret = XNEW (simple_object_read);
 164           ret->descriptor = descriptor;
 165           ret->offset = offset;
 166           ret->functions = format_functions[i];
 167           ret->data = data;
 168           return ret;
 169         }
 170     }
 171
 172   *errmsg = "file not recognized";
 173   *err = 0;
 174   return NULL;
 175 }
 176
 177 /* Find all sections.  */
 178
 179 const char *
 180 simple_object_find_sections (simple_object_read *sobj,
 181                              int (*pfn) (void *, const char *, off_t, off_t),
 182                              void *data,
 183                              int *err)
 184 {
 185   return sobj->functions->find_sections (sobj, pfn, data, err);
 186 }
 187
 188 /* Internal data passed to find_one_section.  */
 189
 190 struct find_one_section_data
 191 {
 192   /* The section we are looking for.  */
 193   const char *name;
 194   /* Where to store the section offset.  */
 195   off_t *offset;
 196   /* Where to store the section length.  */
 197   off_t *length;
 198   /* Set if the name is found.  */
 199   int found;
 200 };
 201
 202 /* Internal function passed to find_sections.  */
 203
 204 static int
 205 find_one_section (void *data, const char *name, off_t offset, off_t length)
 206 {
 207   struct find_one_section_data *fosd = (struct find_one_section_data *) data;
 208
 209   if (strcmp (name, fosd->name) != 0)
 210     return 1;
 211
 212   *fosd->offset = offset;
 213   *fosd->length = length;
 214   fosd->found = 1;
 215
 216   /* Stop iteration.  */
 217   return 0;
 218 }
 219
 220 /* Find a section.  */
 221
 222 int
 223 simple_object_find_section (simple_object_read *sobj, const char *name,
 224                             off_t *offset, off_t *length,
 225                             const char **errmsg, int *err)
 226 {
 227   struct find_one_section_data fosd;
 228
 229   fosd.name = name;
 230   fosd.offset = offset;
 231   fosd.length = length;
 232   fosd.found = 0;
 233
 234   *errmsg = simple_object_find_sections (sobj, find_one_section,
 235                                          (void *) &fosd, err);
 236   if (*errmsg != NULL)
 237     return 0;
 238   if (!fosd.found)
 239     return 0;
 240   return 1;
 241 }
 242
 243 /* Fetch attributes.  */
 244
 245 simple_object_attributes *
 246 simple_object_fetch_attributes (simple_object_read *sobj, const char **errmsg,
 247                                 int *err)
 248 {
 249   void *data;
 250   simple_object_attributes *ret;
 251
 252   data = sobj->functions->fetch_attributes (sobj, errmsg, err);
 253   if (data == NULL)
 254     return NULL;
 255   ret = XNEW (simple_object_attributes);
 256   ret->functions = sobj->functions;
 257   ret->data = data;
 258   return ret;
 259 }
 260
 261 /* Release an simple_object_read.  */
 262
 263 void
 264 simple_object_release_read (simple_object_read *sobj)
 265 {
 266   sobj->functions->release_read (sobj->data);
 267   XDELETE (sobj);
 268 }
 269
 270 /* Merge attributes.  */
 271
 272 const char *
 273 simple_object_attributes_merge (simple_object_attributes *to,
 274                                 simple_object_attributes *from,
 275                                 int *err)
 276 {
 277   if (to->functions != from->functions)
 278     {
 279       *err = 0;
 280       return "different object file format";
 281     }
 282   return to->functions->attributes_merge (to->data, from->data, err);
 283 }
 284
 285 /* Release an attributes structure.  */
 286
 287 void
 288 simple_object_release_attributes (simple_object_attributes *attrs)
 289 {
 290   attrs->functions->release_attributes (attrs->data);
 291   XDELETE (attrs);
 292 }
 293
 294 /* Start creating an object file.  */
 295
 296 simple_object_write *
 297 simple_object_start_write (simple_object_attributes *attrs,
 298                            const char *segment_name, const char **errmsg,
 299                            int *err)
 300 {
 301   void *data;
 302   simple_object_write *ret;
 303
 304   data = attrs->functions->start_write (attrs->data, errmsg, err);
 305   if (data == NULL)
 306     return NULL;
 307   ret = XNEW (simple_object_write);
 308   ret->functions = attrs->functions;
 309   ret->segment_name = xstrdup (segment_name);
 310   ret->sections = NULL;
 311   ret->last_section = NULL;
 312   ret->data = data;
 313   return ret;
 314 }
 315
 316 /* Start creating a section.  */
 317
 318 simple_object_write_section *
 319 simple_object_write_create_section (simple_object_write *sobj, const char *name,
 320                                     unsigned int align,
 321                                     const char **errmsg ATTRIBUTE_UNUSED,
 322                                     int *err ATTRIBUTE_UNUSED)
 323 {
 324   simple_object_write_section *ret;
 325
 326   ret = XNEW (simple_object_write_section);
 327   ret->next = NULL;
 328   ret->name = xstrdup (name);
 329   ret->align = align;
 330   ret->buffers = NULL;
 331   ret->last_buffer = NULL;
 332
 333   if (sobj->last_section == NULL)
 334     {
 335       sobj->sections = ret;
 336       sobj->last_section = ret;
 337     }
 338   else
 339     {
 340       sobj->last_section->next = ret;
 341       sobj->last_section = ret;
 342     }
 343
 344   return ret;
 345 }
 346
 347 /* Add data to a section.  */
 348
 349 const char *
 350 simple_object_write_add_data (simple_object_write *sobj ATTRIBUTE_UNUSED,
 351                               simple_object_write_section *section,
 352                               const void *buffer,
 353                               size_t size, int copy,
 354                               int *err ATTRIBUTE_UNUSED)
 355 {
 356   struct simple_object_write_section_buffer *wsb;
 357
 358   wsb = XNEW (struct simple_object_write_section_buffer);
 359   wsb->next = NULL;
 360   wsb->size = size;
 361
 362   if (!copy)
 363     {
 364       wsb->buffer = buffer;
 365       wsb->free_buffer = NULL;
 366     }
 367   else
 368     {
 369       wsb->free_buffer = (void *) XNEWVEC (char, size);
 370       memcpy (wsb->free_buffer, buffer, size);
 371       wsb->buffer = wsb->free_buffer;
 372     }
 373
 374   if (section->last_buffer == NULL)
 375     {
 376       section->buffers = wsb;
 377       section->last_buffer = wsb;
 378     }
 379   else
 380     {
 381       section->last_buffer->next = wsb;
 382       section->last_buffer = wsb;
 383     }
 384
 385   return NULL;
 386 }
 387
 388 /* Write the complete object file.  */
 389
 390 const char *
 391 simple_object_write_to_file (simple_object_write *sobj, int descriptor,
 392                              int *err)
 393 {
 394   return sobj->functions->write_to_file (sobj, descriptor, err);
 395 }
 396
 397 /* Release an simple_object_write.  */
 398
 399 void
 400 simple_object_release_write (simple_object_write *sobj)
 401 {
 402   simple_object_write_section *section;
 403
 404   free (sobj->segment_name);
 405
 406   section = sobj->sections;
 407   while (section != NULL)
 408     {
 409       struct simple_object_write_section_buffer *buffer;
 410       simple_object_write_section *next_section;
 411
 412       buffer = section->buffers;
 413       while (buffer != NULL)
 414         {
 415           struct simple_object_write_section_buffer *next_buffer;
 416
 417           if (buffer->free_buffer != NULL)
 418             XDELETEVEC (buffer->free_buffer);
 419           next_buffer = buffer->next;
 420           XDELETE (buffer);
 421           buffer = next_buffer;
 422         }
 423
 424       next_section = section->next;
 425       free (section->name);
 426       XDELETE (section);
 427       section = next_section;
 428     }
 429
 430   sobj->functions->release_write (sobj->data);
 431   XDELETE (sobj);
 432 }