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  1. /* Low-level I/O routines for BFDs.
  2.  
  3.    Copyright 1990-2013 Free Software Foundation, Inc.
  4.  
  5.    Written by Cygnus Support.
  6.  
  7.    This file is part of BFD, the Binary File Descriptor library.
  8.  
  9.    This program is free software; you can redistribute it and/or modify
  10.    it under the terms of the GNU General Public License as published by
  11.    the Free Software Foundation; either version 3 of the License, or
  12.    (at your option) any later version.
  13.  
  14.    This program is distributed in the hope that it will be useful,
  15.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17.    GNU General Public License for more details.
  18.  
  19.    You should have received a copy of the GNU General Public License
  20.    along with this program; if not, write to the Free Software
  21.    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  22.    MA 02110-1301, USA.  */
  23.  
  24. #include "sysdep.h"
  25. #include <limits.h>
  26. #include "bfd.h"
  27. #include "libbfd.h"
  28.  
  29. #ifndef S_IXUSR
  30. #define S_IXUSR 0100    /* Execute by owner.  */
  31. #endif
  32. #ifndef S_IXGRP
  33. #define S_IXGRP 0010    /* Execute by group.  */
  34. #endif
  35. #ifndef S_IXOTH
  36. #define S_IXOTH 0001    /* Execute by others.  */
  37. #endif
  38.  
  39. #ifndef FD_CLOEXEC
  40. #define FD_CLOEXEC 1
  41. #endif
  42.  
  43. file_ptr
  44. real_ftell (FILE *file)
  45. {
  46. #if defined (HAVE_FTELLO64)
  47.   return ftello64 (file);
  48. #elif defined (HAVE_FTELLO)
  49.   return ftello (file);
  50. #else
  51.   return ftell (file);
  52. #endif
  53. }
  54.  
  55. int
  56. real_fseek (FILE *file, file_ptr offset, int whence)
  57. {
  58. #if defined (HAVE_FSEEKO64)
  59.   return fseeko64 (file, offset, whence);
  60. #elif defined (HAVE_FSEEKO)
  61.   return fseeko (file, offset, whence);
  62. #else
  63.   return fseek (file, offset, whence);
  64. #endif
  65. }
  66.  
  67. /* Mark FILE as close-on-exec.  Return FILE.  FILE may be NULL, in
  68.    which case nothing is done.  */
  69. static FILE *
  70. close_on_exec (FILE *file)
  71. {
  72. #if defined (HAVE_FILENO) && defined (F_GETFD)
  73.   if (file)
  74.     {
  75.       int fd = fileno (file);
  76.       int old = fcntl (fd, F_GETFD, 0);
  77.       if (old >= 0)
  78.         fcntl (fd, F_SETFD, old | FD_CLOEXEC);
  79.     }
  80. #endif
  81.   return file;
  82. }
  83.  
  84. FILE *
  85. real_fopen (const char *filename, const char *modes)
  86. {
  87. #ifdef VMS
  88.   char *vms_attr;
  89.  
  90.   /* On VMS, fopen allows file attributes as optional arguments.
  91.      We need to use them but we'd better to use the common prototype.
  92.      In fopen-vms.h, they are separated from the mode with a comma.
  93.      Split here.  */
  94.   vms_attr = strchr (modes, ',');
  95.   if (vms_attr == NULL)
  96.     {
  97.       /* No attributes.  */
  98.       return close_on_exec (fopen (filename, modes));
  99.     }
  100.   else
  101.     {
  102.       /* Attributes found.  Split.  */
  103.       size_t modes_len = strlen (modes) + 1;
  104.       char attrs[modes_len + 1];
  105.       char *at[3];
  106.       int i;
  107.  
  108.       memcpy (attrs, modes, modes_len);
  109.       at[0] = attrs;
  110.       for (i = 0; i < 2; i++)
  111.         {
  112.           at[i + 1] = strchr (at[i], ',');
  113.           BFD_ASSERT (at[i + 1] != NULL);
  114.           *(at[i + 1]++) = 0; /* Replace ',' with a nul, and skip it.  */
  115.         }
  116.       return close_on_exec (fopen (filename, at[0], at[1], at[2]));
  117.     }
  118. #else /* !VMS */
  119. #if defined (HAVE_FOPEN64)
  120.   return close_on_exec (fopen64 (filename, modes));
  121. #else
  122.   return close_on_exec (fopen (filename, modes));
  123. #endif
  124. #endif /* !VMS */
  125. }
  126.  
  127. /*
  128. INTERNAL_DEFINITION
  129.         struct bfd_iovec
  130.  
  131. DESCRIPTION
  132.  
  133.         The <<struct bfd_iovec>> contains the internal file I/O class.
  134.         Each <<BFD>> has an instance of this class and all file I/O is
  135.         routed through it (it is assumed that the instance implements
  136.         all methods listed below).
  137.  
  138. .struct bfd_iovec
  139. .{
  140. .  {* To avoid problems with macros, a "b" rather than "f"
  141. .     prefix is prepended to each method name.  *}
  142. .  {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
  143. .     bytes starting at PTR.  Return the number of bytes actually
  144. .     transfered (a read past end-of-file returns less than NBYTES),
  145. .     or -1 (setting <<bfd_error>>) if an error occurs.  *}
  146. .  file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
  147. .  file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
  148. .                      file_ptr nbytes);
  149. .  {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
  150. .     if an error occurs.  *}
  151. .  file_ptr (*btell) (struct bfd *abfd);
  152. .  {* For the following, on successful completion a value of 0 is returned.
  153. .     Otherwise, a value of -1 is returned (and  <<bfd_error>> is set).  *}
  154. .  int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
  155. .  int (*bclose) (struct bfd *abfd);
  156. .  int (*bflush) (struct bfd *abfd);
  157. .  int (*bstat) (struct bfd *abfd, struct stat *sb);
  158. .  {* Mmap a part of the files. ADDR, LEN, PROT, FLAGS and OFFSET are the usual
  159. .     mmap parameter, except that LEN and OFFSET do not need to be page
  160. .     aligned.  Returns (void *)-1 on failure, mmapped address on success.
  161. .     Also write in MAP_ADDR the address of the page aligned buffer and in
  162. .     MAP_LEN the size mapped (a page multiple).  Use unmap with MAP_ADDR and
  163. .     MAP_LEN to unmap.  *}
  164. .  void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
  165. .                  int prot, int flags, file_ptr offset,
  166. .                  void **map_addr, bfd_size_type *map_len);
  167. .};
  168.  
  169. .extern const struct bfd_iovec _bfd_memory_iovec;
  170.  
  171. */
  172.  
  173.  
  174. /* Return value is amount read.  */
  175.  
  176. bfd_size_type
  177. bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
  178. {
  179.   size_t nread;
  180.  
  181.   /* If this is an archive element, don't read past the end of
  182.      this element.  */
  183.   if (abfd->arelt_data != NULL)
  184.     {
  185.       bfd_size_type maxbytes = arelt_size (abfd);
  186.  
  187.       if (abfd->where + size > maxbytes)
  188.         {
  189.           if (abfd->where >= maxbytes)
  190.             return 0;
  191.           size = maxbytes - abfd->where;
  192.         }
  193.     }
  194.  
  195.   if (abfd->iovec)
  196.     nread = abfd->iovec->bread (abfd, ptr, size);
  197.   else
  198.     nread = 0;
  199.   if (nread != (size_t) -1)
  200.     abfd->where += nread;
  201.  
  202.   return nread;
  203. }
  204.  
  205. bfd_size_type
  206. bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
  207. {
  208.   size_t nwrote;
  209.  
  210.   if (abfd->iovec)
  211.     nwrote = abfd->iovec->bwrite (abfd, ptr, size);
  212.   else
  213.     nwrote = 0;
  214.  
  215.   if (nwrote != (size_t) -1)
  216.     abfd->where += nwrote;
  217.   if (nwrote != size)
  218.     {
  219. #ifdef ENOSPC
  220.       errno = ENOSPC;
  221. #endif
  222.       bfd_set_error (bfd_error_system_call);
  223.     }
  224.   return nwrote;
  225. }
  226.  
  227. file_ptr
  228. bfd_tell (bfd *abfd)
  229. {
  230.   file_ptr ptr;
  231.  
  232.   if (abfd->iovec)
  233.     {
  234.       bfd *parent_bfd = abfd;
  235.       ptr = abfd->iovec->btell (abfd);
  236.  
  237.       while (parent_bfd->my_archive != NULL)
  238.         {
  239.           ptr -= parent_bfd->origin;
  240.           parent_bfd = parent_bfd->my_archive;
  241.         }
  242.     }
  243.   else
  244.     ptr = 0;
  245.  
  246.   abfd->where = ptr;
  247.   return ptr;
  248. }
  249.  
  250. int
  251. bfd_flush (bfd *abfd)
  252. {
  253.   if (abfd->iovec)
  254.     return abfd->iovec->bflush (abfd);
  255.   return 0;
  256. }
  257.  
  258. /* Returns 0 for success, negative value for failure (in which case
  259.    bfd_get_error can retrieve the error code).  */
  260. int
  261. bfd_stat (bfd *abfd, struct stat *statbuf)
  262. {
  263.   int result;
  264.  
  265.   if (abfd->iovec)
  266.     result = abfd->iovec->bstat (abfd, statbuf);
  267.   else
  268.     result = -1;
  269.  
  270.   if (result < 0)
  271.     bfd_set_error (bfd_error_system_call);
  272.   return result;
  273. }
  274.  
  275. /* Returns 0 for success, nonzero for failure (in which case bfd_get_error
  276.    can retrieve the error code).  */
  277.  
  278. int
  279. bfd_seek (bfd *abfd, file_ptr position, int direction)
  280. {
  281.   int result;
  282.   file_ptr file_position;
  283.   /* For the time being, a BFD may not seek to it's end.  The problem
  284.      is that we don't easily have a way to recognize the end of an
  285.      element in an archive.  */
  286.  
  287.   BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);
  288.  
  289.   if (direction == SEEK_CUR && position == 0)
  290.     return 0;
  291.  
  292.   if (abfd->format != bfd_archive && abfd->my_archive == 0)
  293.     {
  294.       if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
  295.         return 0;
  296.     }
  297.   else
  298.     {
  299.       /* We need something smarter to optimize access to archives.
  300.          Currently, anything inside an archive is read via the file
  301.          handle for the archive.  Which means that a bfd_seek on one
  302.          component affects the `current position' in the archive, as
  303.          well as in any other component.
  304.  
  305.          It might be sufficient to put a spike through the cache
  306.          abstraction, and look to the archive for the file position,
  307.          but I think we should try for something cleaner.
  308.  
  309.          In the meantime, no optimization for archives.  */
  310.     }
  311.  
  312.   file_position = position;
  313.   if (direction == SEEK_SET)
  314.     {
  315.       bfd *parent_bfd = abfd;
  316.  
  317.       while (parent_bfd->my_archive != NULL)
  318.         {
  319.           file_position += parent_bfd->origin;
  320.           parent_bfd = parent_bfd->my_archive;
  321.         }
  322.     }
  323.  
  324.   if (abfd->iovec)
  325.     result = abfd->iovec->bseek (abfd, file_position, direction);
  326.   else
  327.     result = -1;
  328.  
  329.   if (result != 0)
  330.     {
  331.       int hold_errno = errno;
  332.  
  333.       /* Force redetermination of `where' field.  */
  334.       bfd_tell (abfd);
  335.  
  336.       /* An EINVAL error probably means that the file offset was
  337.          absurd.  */
  338.       if (hold_errno == EINVAL)
  339.         bfd_set_error (bfd_error_file_truncated);
  340.       else
  341.         {
  342.           bfd_set_error (bfd_error_system_call);
  343.           errno = hold_errno;
  344.         }
  345.     }
  346.   else
  347.     {
  348.       /* Adjust `where' field.  */
  349.       if (direction == SEEK_SET)
  350.         abfd->where = position;
  351.       else
  352.         abfd->where += position;
  353.     }
  354.   return result;
  355. }
  356.  
  357. /*
  358. FUNCTION
  359.         bfd_get_mtime
  360.  
  361. SYNOPSIS
  362.         long bfd_get_mtime (bfd *abfd);
  363.  
  364. DESCRIPTION
  365.         Return the file modification time (as read from the file system, or
  366.         from the archive header for archive members).
  367.  
  368. */
  369.  
  370. long
  371. bfd_get_mtime (bfd *abfd)
  372. {
  373.   struct stat buf;
  374.  
  375.   if (abfd->mtime_set)
  376.     return abfd->mtime;
  377.  
  378.   if (abfd->iovec == NULL)
  379.     return 0;
  380.  
  381.   if (abfd->iovec->bstat (abfd, &buf) != 0)
  382.     return 0;
  383.  
  384.   abfd->mtime = buf.st_mtime;           /* Save value in case anyone wants it */
  385.   return buf.st_mtime;
  386. }
  387.  
  388. /*
  389. FUNCTION
  390.         bfd_get_size
  391.  
  392. SYNOPSIS
  393.         file_ptr bfd_get_size (bfd *abfd);
  394.  
  395. DESCRIPTION
  396.         Return the file size (as read from file system) for the file
  397.         associated with BFD @var{abfd}.
  398.  
  399.         The initial motivation for, and use of, this routine is not
  400.         so we can get the exact size of the object the BFD applies to, since
  401.         that might not be generally possible (archive members for example).
  402.         It would be ideal if someone could eventually modify
  403.         it so that such results were guaranteed.
  404.  
  405.         Instead, we want to ask questions like "is this NNN byte sized
  406.         object I'm about to try read from file offset YYY reasonable?"
  407.         As as example of where we might do this, some object formats
  408.         use string tables for which the first <<sizeof (long)>> bytes of the
  409.         table contain the size of the table itself, including the size bytes.
  410.         If an application tries to read what it thinks is one of these
  411.         string tables, without some way to validate the size, and for
  412.         some reason the size is wrong (byte swapping error, wrong location
  413.         for the string table, etc.), the only clue is likely to be a read
  414.         error when it tries to read the table, or a "virtual memory
  415.         exhausted" error when it tries to allocate 15 bazillon bytes
  416.         of space for the 15 bazillon byte table it is about to read.
  417.         This function at least allows us to answer the question, "is the
  418.         size reasonable?".
  419. */
  420.  
  421. file_ptr
  422. bfd_get_size (bfd *abfd)
  423. {
  424.   struct stat buf;
  425.  
  426.   if (abfd->iovec == NULL)
  427.     return 0;
  428.  
  429.   if (abfd->iovec->bstat (abfd, &buf) != 0)
  430.     return 0;
  431.  
  432.   return buf.st_size;
  433. }
  434.  
  435.  
  436. /*
  437. FUNCTION
  438.         bfd_mmap
  439.  
  440. SYNOPSIS
  441.         void *bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
  442.                         int prot, int flags, file_ptr offset,
  443.                         void **map_addr, bfd_size_type *map_len);
  444.  
  445. DESCRIPTION
  446.         Return mmap()ed region of the file, if possible and implemented.
  447.         LEN and OFFSET do not need to be page aligned.  The page aligned
  448.         address and length are written to MAP_ADDR and MAP_LEN.
  449.  
  450. */
  451.  
  452. void *
  453. bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
  454.           int prot, int flags, file_ptr offset,
  455.           void **map_addr, bfd_size_type *map_len)
  456. {
  457.   void *ret = (void *)-1;
  458.  
  459.   if (abfd->iovec == NULL)
  460.     return ret;
  461.  
  462.   return abfd->iovec->bmmap (abfd, addr, len, prot, flags, offset,
  463.                              map_addr, map_len);
  464. }
  465.  
  466. /* Memory file I/O operations.  */
  467.  
  468. static file_ptr
  469. memory_bread (bfd *abfd, void *ptr, file_ptr size)
  470. {
  471.   struct bfd_in_memory *bim;
  472.   bfd_size_type get;
  473.  
  474.   bim = (struct bfd_in_memory *) abfd->iostream;
  475.   get = size;
  476.   if (abfd->where + get > bim->size)
  477.     {
  478.       if (bim->size < (bfd_size_type) abfd->where)
  479.         get = 0;
  480.       else
  481.         get = bim->size - abfd->where;
  482.       bfd_set_error (bfd_error_file_truncated);
  483.     }
  484.   memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
  485.   return get;
  486. }
  487.  
  488. static file_ptr
  489. memory_bwrite (bfd *abfd, const void *ptr, file_ptr size)
  490. {
  491.   struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream;
  492.  
  493.   if (abfd->where + size > bim->size)
  494.     {
  495.       bfd_size_type newsize, oldsize;
  496.  
  497.       oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
  498.       bim->size = abfd->where + size;
  499.       /* Round up to cut down on memory fragmentation */
  500.       newsize = (bim->size + 127) & ~(bfd_size_type) 127;
  501.       if (newsize > oldsize)
  502.         {
  503.           bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, newsize);
  504.           if (bim->buffer == NULL)
  505.             {
  506.               bim->size = 0;
  507.               return 0;
  508.             }
  509.           if (newsize > bim->size)
  510.             memset (bim->buffer + bim->size, 0, newsize - bim->size);
  511.         }
  512.     }
  513.   memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
  514.   return size;
  515. }
  516.  
  517. static file_ptr
  518. memory_btell (bfd *abfd)
  519. {
  520.   return abfd->where;
  521. }
  522.  
  523. static int
  524. memory_bseek (bfd *abfd, file_ptr position, int direction)
  525. {
  526.   file_ptr nwhere;
  527.   struct bfd_in_memory *bim;
  528.  
  529.   bim = (struct bfd_in_memory *) abfd->iostream;
  530.  
  531.   if (direction == SEEK_SET)
  532.     nwhere = position;
  533.   else
  534.     nwhere = abfd->where + position;
  535.  
  536.   if (nwhere < 0)
  537.     {
  538.       abfd->where = 0;
  539.       errno = EINVAL;
  540.       return -1;
  541.     }
  542.  
  543.   if ((bfd_size_type)nwhere > bim->size)
  544.     {
  545.       if (abfd->direction == write_direction
  546.           || abfd->direction == both_direction)
  547.         {
  548.           bfd_size_type newsize, oldsize;
  549.  
  550.           oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
  551.           bim->size = nwhere;
  552.           /* Round up to cut down on memory fragmentation */
  553.           newsize = (bim->size + 127) & ~(bfd_size_type) 127;
  554.           if (newsize > oldsize)
  555.             {
  556.               bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, newsize);
  557.               if (bim->buffer == NULL)
  558.                 {
  559.                   errno = EINVAL;
  560.                   bim->size = 0;
  561.                   return -1;
  562.                 }
  563.               memset (bim->buffer + oldsize, 0, newsize - oldsize);
  564.             }
  565.         }
  566.       else
  567.         {
  568.           abfd->where = bim->size;
  569.           errno = EINVAL;
  570.           bfd_set_error (bfd_error_file_truncated);
  571.           return -1;
  572.         }
  573.     }
  574.   return 0;
  575. }
  576.  
  577. static int
  578. memory_bclose (struct bfd *abfd)
  579. {
  580.   struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream;
  581.  
  582.   if (bim->buffer != NULL)
  583.     free (bim->buffer);
  584.   free (bim);
  585.   abfd->iostream = NULL;
  586.  
  587.   return 0;
  588. }
  589.  
  590. static int
  591. memory_bflush (bfd *abfd ATTRIBUTE_UNUSED)
  592. {
  593.   return 0;
  594. }
  595.  
  596. static int
  597. memory_bstat (bfd *abfd, struct stat *statbuf)
  598. {
  599.   struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream;
  600.  
  601.   memset (statbuf, 0, sizeof (*statbuf));
  602.   statbuf->st_size = bim->size;
  603.  
  604.   return 0;
  605. }
  606.  
  607. static void *
  608. memory_bmmap (bfd *abfd ATTRIBUTE_UNUSED, void *addr ATTRIBUTE_UNUSED,
  609.               bfd_size_type len ATTRIBUTE_UNUSED, int prot ATTRIBUTE_UNUSED,
  610.               int flags ATTRIBUTE_UNUSED, file_ptr offset ATTRIBUTE_UNUSED,
  611.               void **map_addr ATTRIBUTE_UNUSED,
  612.               bfd_size_type *map_len ATTRIBUTE_UNUSED)
  613. {
  614.   return (void *)-1;
  615. }
  616.  
  617. const struct bfd_iovec _bfd_memory_iovec =
  618. {
  619.   &memory_bread, &memory_bwrite, &memory_btell, &memory_bseek,
  620.   &memory_bclose, &memory_bflush, &memory_bstat, &memory_bmmap
  621. };
  622.