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 };
  56
  57 /* Read data from a file using the simple_object error reporting
  58    conventions.  */
  59
  60 int
  61 simple_object_internal_read (int descriptor, off_t offset,
  62                              unsigned char *buffer, size_t size,
  63                              const char **errmsg, int *err)
  64 {
  65   ssize_t got;
  66
  67   if (lseek (descriptor, offset, SEEK_SET) < 0)
  68     {
  69       *errmsg = "lseek";
  70       *err = errno;
  71       return 0;
  72     }
  73
  74   got = read (descriptor, buffer, size);
  75   if (got < 0)
  76     {
  77       *errmsg = "read";
  78       *err = errno;
  79       return 0;
  80     }
  81
  82   if ((size_t) got < size)
  83     {
  84       *errmsg = "file too short";
  85       *err = 0;
  86       return 0;
  87     }
  88
  89   return 1;
  90 }
  91
  92 /* Write data to a file using the simple_object error reporting
  93    conventions.  */
  94
  95 int
  96 simple_object_internal_write (int descriptor, off_t offset,
  97                               const unsigned char *buffer, size_t size,
  98                               const char **errmsg, int *err)
  99 {
 100   ssize_t wrote;
 101
 102   if (lseek (descriptor, offset, SEEK_SET) < 0)
 103     {
 104       *errmsg = "lseek";
 105       *err = errno;
 106       return 0;
 107     }
 108
 109   wrote = write (descriptor, buffer, size);
 110   if (wrote < 0)
 111     {
 112       *errmsg = "write";
 113       *err = errno;
 114       return 0;
 115     }
 116
 117   if ((size_t) wrote < size)
 118     {
 119       *errmsg = "short write";
 120       *err = 0;
 121       return 0;
 122     }
 123
 124   return 1;
 125 }
 126
 127 /* Open for read.  */
 128
 129 simple_object_read *
 130 simple_object_start_read (int descriptor, off_t offset,
 131                           const char *segment_name, const char **errmsg,
 132                           int *err)
 133 {
 134   unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN];
 135   size_t len, i;
 136
 137   if (!simple_object_internal_read (descriptor, offset, header,
 138                                     SIMPLE_OBJECT_MATCH_HEADER_LEN,
 139                                     errmsg, err))
 140     return NULL;
 141
 142   len = sizeof (format_functions) / sizeof (format_functions[0]);
 143   for (i = 0; i < len; ++i)
 144     {
 145       void *data;
 146
 147       data = format_functions[i]->match (header, descriptor, offset,
 148                                          segment_name, errmsg, err);
 149       if (data != NULL)
 150         {
 151           simple_object_read *ret;
 152
 153           ret = XNEW (simple_object_read);
 154           ret->descriptor = descriptor;
 155           ret->offset = offset;
 156           ret->functions = format_functions[i];
 157           ret->data = data;
 158           return ret;
 159         }
 160     }
 161
 162   *errmsg = "file not recognized";
 163   *err = 0;
 164   return NULL;
 165 }
 166
 167 /* Find all sections.  */
 168
 169 const char *
 170 simple_object_find_sections (simple_object_read *sobj,
 171                              int (*pfn) (void *, const char *, off_t, off_t),
 172                              void *data,
 173                              int *err)
 174 {
 175   return sobj->functions->find_sections (sobj, pfn, data, err);
 176 }
 177
 178 /* Internal data passed to find_one_section.  */
 179
 180 struct find_one_section_data
 181 {
 182   /* The section we are looking for.  */
 183   const char *name;
 184   /* Where to store the section offset.  */
 185   off_t *offset;
 186   /* Where to store the section length.  */
 187   off_t *length;
 188   /* Set if the name is found.  */
 189   int found;
 190 };
 191
 192 /* Internal function passed to find_sections.  */
 193
 194 static int
 195 find_one_section (void *data, const char *name, off_t offset, off_t length)
 196 {
 197   struct find_one_section_data *fosd = (struct find_one_section_data *) data;
 198
 199   if (strcmp (name, fosd->name) != 0)
 200     return 1;
 201
 202   *fosd->offset = offset;
 203   *fosd->length = length;
 204   fosd->found = 1;
 205
 206   /* Stop iteration.  */
 207   return 0;
 208 }
 209
 210 /* Find a section.  */
 211
 212 int
 213 simple_object_find_section (simple_object_read *sobj, const char *name,
 214                             off_t *offset, off_t *length,
 215                             const char **errmsg, int *err)
 216 {
 217   struct find_one_section_data fosd;
 218
 219   fosd.name = name;
 220   fosd.offset = offset;
 221   fosd.length = length;
 222   fosd.found = 0;
 223
 224   *errmsg = simple_object_find_sections (sobj, find_one_section,
 225                                          (void *) &fosd, err);
 226   if (*errmsg != NULL)
 227     return 0;
 228   if (!fosd.found)
 229     return 0;
 230   return 1;
 231 }
 232
 233 /* Fetch attributes.  */
 234
 235 simple_object_attributes *
 236 simple_object_fetch_attributes (simple_object_read *sobj, const char **errmsg,
 237                                 int *err)
 238 {
 239   void *data;
 240   simple_object_attributes *ret;
 241
 242   data = sobj->functions->fetch_attributes (sobj, errmsg, err);
 243   if (data == NULL)
 244     return NULL;
 245   ret = XNEW (simple_object_attributes);
 246   ret->functions = sobj->functions;
 247   ret->data = data;
 248   return ret;
 249 }
 250
 251 /* Release an simple_object_read.  */
 252
 253 void
 254 simple_object_release_read (simple_object_read *sobj)
 255 {
 256   sobj->functions->release_read (sobj->data);
 257   XDELETE (sobj);
 258 }
 259
 260 /* Compare attributes.  */
 261
 262 const char *
 263 simple_object_attributes_compare (simple_object_attributes *attrs1,
 264                                   simple_object_attributes *attrs2,
 265                                   int *err)
 266 {
 267   if (attrs1->functions != attrs2->functions)
 268     {
 269       *err = 0;
 270       return "different object file format";
 271     }
 272   return attrs1->functions->attributes_compare (attrs1->data, attrs2->data,
 273                                                 err);
 274 }
 275
 276 /* Release an attributes structure.  */
 277
 278 void
 279 simple_object_release_attributes (simple_object_attributes *attrs)
 280 {
 281   attrs->functions->release_attributes (attrs->data);
 282   XDELETE (attrs);
 283 }
 284
 285 /* Start creating an object file.  */
 286
 287 simple_object_write *
 288 simple_object_start_write (simple_object_attributes *attrs,
 289                            const char *segment_name, const char **errmsg,
 290                            int *err)
 291 {
 292   void *data;
 293   simple_object_write *ret;
 294
 295   data = attrs->functions->start_write (attrs->data, errmsg, err);
 296   if (data == NULL)
 297     return NULL;
 298   ret = XNEW (simple_object_write);
 299   ret->functions = attrs->functions;
 300   ret->segment_name = xstrdup (segment_name);
 301   ret->sections = NULL;
 302   ret->last_section = NULL;
 303   ret->data = data;
 304   return ret;
 305 }
 306
 307 /* Start creating a section.  */
 308
 309 simple_object_write_section *
 310 simple_object_write_create_section (simple_object_write *sobj, const char *name,
 311                                     unsigned int align,
 312                                     const char **errmsg ATTRIBUTE_UNUSED,
 313                                     int *err ATTRIBUTE_UNUSED)
 314 {
 315   simple_object_write_section *ret;
 316
 317   ret = XNEW (simple_object_write_section);
 318   ret->next = NULL;
 319   ret->name = xstrdup (name);
 320   ret->align = align;
 321   ret->buffers = NULL;
 322   ret->last_buffer = NULL;
 323
 324   if (sobj->last_section == NULL)
 325     {
 326       sobj->sections = ret;
 327       sobj->last_section = ret;
 328     }
 329   else
 330     {
 331       sobj->last_section->next = ret;
 332       sobj->last_section = ret;
 333     }
 334
 335   return ret;
 336 }
 337
 338 /* Add data to a section.  */
 339
 340 const char *
 341 simple_object_write_add_data (simple_object_write *sobj ATTRIBUTE_UNUSED,
 342                               simple_object_write_section *section,
 343                               const void *buffer,
 344                               size_t size, int copy,
 345                               int *err ATTRIBUTE_UNUSED)
 346 {
 347   struct simple_object_write_section_buffer *wsb;
 348
 349   wsb = XNEW (struct simple_object_write_section_buffer);
 350   wsb->next = NULL;
 351   wsb->size = size;
 352
 353   if (!copy)
 354     {
 355       wsb->buffer = buffer;
 356       wsb->free_buffer = NULL;
 357     }
 358   else
 359     {
 360       wsb->free_buffer = (void *) XNEWVEC (char, size);
 361       memcpy (wsb->free_buffer, buffer, size);
 362       wsb->buffer = wsb->free_buffer;
 363     }
 364
 365   if (section->last_buffer == NULL)
 366     {
 367       section->buffers = wsb;
 368       section->last_buffer = wsb;
 369     }
 370   else
 371     {
 372       section->last_buffer->next = wsb;
 373       section->last_buffer = wsb;
 374     }
 375
 376   return NULL;
 377 }
 378
 379 /* Write the complete object file.  */
 380
 381 const char *
 382 simple_object_write_to_file (simple_object_write *sobj, int descriptor,
 383                              int *err)
 384 {
 385   return sobj->functions->write_to_file (sobj, descriptor, err);
 386 }
 387
 388 /* Release an simple_object_write.  */
 389
 390 void
 391 simple_object_release_write (simple_object_write *sobj)
 392 {
 393   simple_object_write_section *section;
 394
 395   free (sobj->segment_name);
 396
 397   section = sobj->sections;
 398   while (section != NULL)
 399     {
 400       struct simple_object_write_section_buffer *buffer;
 401       simple_object_write_section *next_section;
 402
 403       buffer = section->buffers;
 404       while (buffer != NULL)
 405         {
 406           struct simple_object_write_section_buffer *next_buffer;
 407
 408           if (buffer->free_buffer != NULL)
 409             XDELETEVEC (buffer->free_buffer);
 410           next_buffer = buffer->next;
 411           XDELETE (buffer);
 412           buffer = next_buffer;
 413         }
 414
 415       next_section = section->next;
 416       free (section->name);
 417       XDELETE (section);
 418       section = next_section;
 419     }
 420
 421   sobj->functions->release_write (sobj->data);
 422   XDELETE (sobj);
 423 }