libiberty/simple-object.c

   1 /* simple-object.c -- simple routines to read and write object files.
   2    Copyright (C) 2010-2017 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   if (lseek (descriptor, offset, SEEK_SET) < 0)
 111     {
 112       *errmsg = "lseek";
 113       *err = errno;
 114       return 0;
 115     }
 116
 117   do
 118     {
 119       ssize_t wrote = write (descriptor, buffer, size);
 120       if (wrote == 0)
 121         break;
 122       else if (wrote > 0)
 123         {
 124           buffer += wrote;
 125           size -= wrote;
 126         }
 127       else if (errno != EINTR)
 128         {
 129           *errmsg = "write";
 130           *err = errno;
 131           return 0;
 132         }
 133     }
 134   while (size > 0);
 135
 136   if (size > 0)
 137     {
 138       *errmsg = "short write";
 139       *err = 0;
 140       return 0;
 141     }
 142
 143   return 1;
 144 }
 145
 146 /* Open for read.  */
 147
 148 simple_object_read *
 149 simple_object_start_read (int descriptor, off_t offset,
 150                           const char *segment_name, const char **errmsg,
 151                           int *err)
 152 {
 153   unsigned char header[SIMPLE_OBJECT_MATCH_HEADER_LEN];
 154   size_t len, i;
 155
 156   if (!simple_object_internal_read (descriptor, offset, header,
 157                                     SIMPLE_OBJECT_MATCH_HEADER_LEN,
 158                                     errmsg, err))
 159     return NULL;
 160
 161   len = sizeof (format_functions) / sizeof (format_functions[0]);
 162   for (i = 0; i < len; ++i)
 163     {
 164       void *data;
 165
 166       data = format_functions[i]->match (header, descriptor, offset,
 167                                          segment_name, errmsg, err);
 168       if (data != NULL)
 169         {
 170           simple_object_read *ret;
 171
 172           ret = XNEW (simple_object_read);
 173           ret->descriptor = descriptor;
 174           ret->offset = offset;
 175           ret->functions = format_functions[i];
 176           ret->data = data;
 177           return ret;
 178         }
 179     }
 180
 181   *errmsg = "file not recognized";
 182   *err = 0;
 183   return NULL;
 184 }
 185
 186 /* Find all sections.  */
 187
 188 const char *
 189 simple_object_find_sections (simple_object_read *sobj,
 190                              int (*pfn) (void *, const char *, off_t, off_t),
 191                              void *data,
 192                              int *err)
 193 {
 194   return sobj->functions->find_sections (sobj, pfn, data, err);
 195 }
 196
 197 /* Internal data passed to find_one_section.  */
 198
 199 struct find_one_section_data
 200 {
 201   /* The section we are looking for.  */
 202   const char *name;
 203   /* Where to store the section offset.  */
 204   off_t *offset;
 205   /* Where to store the section length.  */
 206   off_t *length;
 207   /* Set if the name is found.  */
 208   int found;
 209 };
 210
 211 /* Internal function passed to find_sections.  */
 212
 213 static int
 214 find_one_section (void *data, const char *name, off_t offset, off_t length)
 215 {
 216   struct find_one_section_data *fosd = (struct find_one_section_data *) data;
 217
 218   if (strcmp (name, fosd->name) != 0)
 219     return 1;
 220
 221   *fosd->offset = offset;
 222   *fosd->length = length;
 223   fosd->found = 1;
 224
 225   /* Stop iteration.  */
 226   return 0;
 227 }
 228
 229 /* Find a section.  */
 230
 231 int
 232 simple_object_find_section (simple_object_read *sobj, const char *name,
 233                             off_t *offset, off_t *length,
 234                             const char **errmsg, int *err)
 235 {
 236   struct find_one_section_data fosd;
 237
 238   fosd.name = name;
 239   fosd.offset = offset;
 240   fosd.length = length;
 241   fosd.found = 0;
 242
 243   *errmsg = simple_object_find_sections (sobj, find_one_section,
 244                                          (void *) &fosd, err);
 245   if (*errmsg != NULL)
 246     return 0;
 247   if (!fosd.found)
 248     return 0;
 249   return 1;
 250 }
 251
 252 /* Fetch attributes.  */
 253
 254 simple_object_attributes *
 255 simple_object_fetch_attributes (simple_object_read *sobj, const char **errmsg,
 256                                 int *err)
 257 {
 258   void *data;
 259   simple_object_attributes *ret;
 260
 261   data = sobj->functions->fetch_attributes (sobj, errmsg, err);
 262   if (data == NULL)
 263     return NULL;
 264   ret = XNEW (simple_object_attributes);
 265   ret->functions = sobj->functions;
 266   ret->data = data;
 267   return ret;
 268 }
 269
 270 /* Release an simple_object_read.  */
 271
 272 void
 273 simple_object_release_read (simple_object_read *sobj)
 274 {
 275   sobj->functions->release_read (sobj->data);
 276   XDELETE (sobj);
 277 }
 278
 279 /* Merge attributes.  */
 280
 281 const char *
 282 simple_object_attributes_merge (simple_object_attributes *to,
 283                                 simple_object_attributes *from,
 284                                 int *err)
 285 {
 286   if (to->functions != from->functions)
 287     {
 288       *err = 0;
 289       return "different object file format";
 290     }
 291   return to->functions->attributes_merge (to->data, from->data, err);
 292 }
 293
 294 /* Release an attributes structure.  */
 295
 296 void
 297 simple_object_release_attributes (simple_object_attributes *attrs)
 298 {
 299   attrs->functions->release_attributes (attrs->data);
 300   XDELETE (attrs);
 301 }
 302
 303 /* Start creating an object file.  */
 304
 305 simple_object_write *
 306 simple_object_start_write (simple_object_attributes *attrs,
 307                            const char *segment_name, const char **errmsg,
 308                            int *err)
 309 {
 310   void *data;
 311   simple_object_write *ret;
 312
 313   data = attrs->functions->start_write (attrs->data, errmsg, err);
 314   if (data == NULL)
 315     return NULL;
 316   ret = XNEW (simple_object_write);
 317   ret->functions = attrs->functions;
 318   ret->segment_name = xstrdup (segment_name);
 319   ret->sections = NULL;
 320   ret->last_section = NULL;
 321   ret->data = data;
 322   return ret;
 323 }
 324
 325 /* Start creating a section.  */
 326
 327 simple_object_write_section *
 328 simple_object_write_create_section (simple_object_write *sobj, const char *name,
 329                                     unsigned int align,
 330                                     const char **errmsg ATTRIBUTE_UNUSED,
 331                                     int *err ATTRIBUTE_UNUSED)
 332 {
 333   simple_object_write_section *ret;
 334
 335   ret = XNEW (simple_object_write_section);
 336   ret->next = NULL;
 337   ret->name = xstrdup (name);
 338   ret->align = align;
 339   ret->buffers = NULL;
 340   ret->last_buffer = NULL;
 341
 342   if (sobj->last_section == NULL)
 343     {
 344       sobj->sections = ret;
 345       sobj->last_section = ret;
 346     }
 347   else
 348     {
 349       sobj->last_section->next = ret;
 350       sobj->last_section = ret;
 351     }
 352
 353   return ret;
 354 }
 355
 356 /* Add data to a section.  */
 357
 358 const char *
 359 simple_object_write_add_data (simple_object_write *sobj ATTRIBUTE_UNUSED,
 360                               simple_object_write_section *section,
 361                               const void *buffer,
 362                               size_t size, int copy,
 363                               int *err ATTRIBUTE_UNUSED)
 364 {
 365   struct simple_object_write_section_buffer *wsb;
 366
 367   wsb = XNEW (struct simple_object_write_section_buffer);
 368   wsb->next = NULL;
 369   wsb->size = size;
 370
 371   if (!copy)
 372     {
 373       wsb->buffer = buffer;
 374       wsb->free_buffer = NULL;
 375     }
 376   else
 377     {
 378       wsb->free_buffer = (void *) XNEWVEC (char, size);
 379       memcpy (wsb->free_buffer, buffer, size);
 380       wsb->buffer = wsb->free_buffer;
 381     }
 382
 383   if (section->last_buffer == NULL)
 384     {
 385       section->buffers = wsb;
 386       section->last_buffer = wsb;
 387     }
 388   else
 389     {
 390       section->last_buffer->next = wsb;
 391       section->last_buffer = wsb;
 392     }
 393
 394   return NULL;
 395 }
 396
 397 /* Write the complete object file.  */
 398
 399 const char *
 400 simple_object_write_to_file (simple_object_write *sobj, int descriptor,
 401                              int *err)
 402 {
 403   return sobj->functions->write_to_file (sobj, descriptor, err);
 404 }
 405
 406 /* Release an simple_object_write.  */
 407
 408 void
 409 simple_object_release_write (simple_object_write *sobj)
 410 {
 411   simple_object_write_section *section;
 412
 413   free (sobj->segment_name);
 414
 415   section = sobj->sections;
 416   while (section != NULL)
 417     {
 418       struct simple_object_write_section_buffer *buffer;
 419       simple_object_write_section *next_section;
 420
 421       buffer = section->buffers;
 422       while (buffer != NULL)
 423         {
 424           struct simple_object_write_section_buffer *next_buffer;
 425
 426           if (buffer->free_buffer != NULL)
 427             XDELETEVEC (buffer->free_buffer);
 428           next_buffer = buffer->next;
 429           XDELETE (buffer);
 430           buffer = next_buffer;
 431         }
 432
 433       next_section = section->next;
 434       free (section->name);
 435       XDELETE (section);
 436       section = next_section;
 437     }
 438
 439   sobj->functions->release_write (sobj->data);
 440   XDELETE (sobj);
 441 }