624 lines
16 KiB
C
624 lines
16 KiB
C
/* Low-level I/O routines for BFDs.
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Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
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1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011
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Free Software Foundation, Inc.
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Written by Cygnus Support.
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This file is part of BFD, the Binary File Descriptor library.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "sysdep.h"
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#include <limits.h>
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#include "bfd.h"
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#include "libbfd.h"
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#ifndef S_IXUSR
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#define S_IXUSR 0100 /* Execute by owner. */
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#endif
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#ifndef S_IXGRP
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#define S_IXGRP 0010 /* Execute by group. */
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#endif
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#ifndef S_IXOTH
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#define S_IXOTH 0001 /* Execute by others. */
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#endif
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#ifndef FD_CLOEXEC
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#define FD_CLOEXEC 1
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#endif
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file_ptr
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real_ftell (FILE *file)
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{
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#if defined (HAVE_FTELLO64)
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return ftello64 (file);
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#elif defined (HAVE_FTELLO)
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return ftello (file);
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#else
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return ftell (file);
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#endif
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}
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int
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real_fseek (FILE *file, file_ptr offset, int whence)
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{
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#if defined (HAVE_FSEEKO64)
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return fseeko64 (file, offset, whence);
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#elif defined (HAVE_FSEEKO)
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return fseeko (file, offset, whence);
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#else
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return fseek (file, offset, whence);
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#endif
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}
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/* Mark FILE as close-on-exec. Return FILE. FILE may be NULL, in
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which case nothing is done. */
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static FILE *
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close_on_exec (FILE *file)
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{
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#if defined (HAVE_FILENO) && defined (F_GETFD)
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if (file)
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{
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int fd = fileno (file);
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int old = fcntl (fd, F_GETFD, 0);
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if (old >= 0)
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fcntl (fd, F_SETFD, old | FD_CLOEXEC);
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}
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#endif
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return file;
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}
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FILE *
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real_fopen (const char *filename, const char *modes)
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{
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#ifdef VMS
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char *vms_attr;
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/* On VMS, fopen allows file attributes as optionnal arguments.
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We need to use them but we'd better to use the common prototype.
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In fopen-vms.h, they are separated from the mode with a comma.
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Split here. */
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vms_attr = strchr (modes, ',');
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if (vms_attr == NULL)
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{
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/* No attributes. */
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return close_on_exec (fopen (filename, modes));
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}
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else
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{
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/* Attributes found. Split. */
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size_t modes_len = strlen (modes) + 1;
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char attrs[modes_len + 1];
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char *at[3];
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int i;
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memcpy (attrs, modes, modes_len);
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at[0] = attrs;
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for (i = 0; i < 2; i++)
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{
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at[i + 1] = strchr (at[i], ',');
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BFD_ASSERT (at[i + 1] != NULL);
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*(at[i + 1]++) = 0; /* Replace ',' with a nul, and skip it. */
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}
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return close_on_exec (fopen (filename, at[0], at[1], at[2]));
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}
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#else /* !VMS */
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#if defined (HAVE_FOPEN64)
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return close_on_exec (fopen64 (filename, modes));
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#else
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return close_on_exec (fopen (filename, modes));
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#endif
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#endif /* !VMS */
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}
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/*
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INTERNAL_DEFINITION
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struct bfd_iovec
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DESCRIPTION
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The <<struct bfd_iovec>> contains the internal file I/O class.
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Each <<BFD>> has an instance of this class and all file I/O is
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routed through it (it is assumed that the instance implements
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all methods listed below).
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.struct bfd_iovec
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.{
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. {* To avoid problems with macros, a "b" rather than "f"
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. prefix is prepended to each method name. *}
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. {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
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. bytes starting at PTR. Return the number of bytes actually
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. transfered (a read past end-of-file returns less than NBYTES),
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. or -1 (setting <<bfd_error>>) if an error occurs. *}
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. file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
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. file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
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. file_ptr nbytes);
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. {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
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. if an error occurs. *}
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. file_ptr (*btell) (struct bfd *abfd);
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. {* For the following, on successful completion a value of 0 is returned.
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. Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *}
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. int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
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. int (*bclose) (struct bfd *abfd);
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. int (*bflush) (struct bfd *abfd);
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. int (*bstat) (struct bfd *abfd, struct stat *sb);
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. {* Mmap a part of the files. ADDR, LEN, PROT, FLAGS and OFFSET are the usual
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. mmap parameter, except that LEN and OFFSET do not need to be page
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. aligned. Returns (void *)-1 on failure, mmapped address on success.
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. Also write in MAP_ADDR the address of the page aligned buffer and in
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. MAP_LEN the size mapped (a page multiple). Use unmap with MAP_ADDR and
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. MAP_LEN to unmap. *}
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. void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
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. int prot, int flags, file_ptr offset,
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. void **map_addr, bfd_size_type *map_len);
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.};
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.extern const struct bfd_iovec _bfd_memory_iovec;
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*/
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/* Return value is amount read. */
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bfd_size_type
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bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
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{
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size_t nread;
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/* If this is an archive element, don't read past the end of
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this element. */
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if (abfd->arelt_data != NULL)
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{
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bfd_size_type maxbytes = arelt_size (abfd);
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if (abfd->where + size > maxbytes)
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{
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if (abfd->where >= maxbytes)
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return 0;
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size = maxbytes - abfd->where;
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}
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}
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if (abfd->iovec)
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nread = abfd->iovec->bread (abfd, ptr, size);
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else
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nread = 0;
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if (nread != (size_t) -1)
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abfd->where += nread;
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return nread;
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}
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bfd_size_type
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bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
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{
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size_t nwrote;
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if (abfd->iovec)
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nwrote = abfd->iovec->bwrite (abfd, ptr, size);
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else
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nwrote = 0;
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if (nwrote != (size_t) -1)
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abfd->where += nwrote;
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if (nwrote != size)
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{
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#ifdef ENOSPC
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errno = ENOSPC;
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#endif
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bfd_set_error (bfd_error_system_call);
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}
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return nwrote;
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}
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file_ptr
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bfd_tell (bfd *abfd)
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{
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file_ptr ptr;
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if (abfd->iovec)
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{
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bfd *parent_bfd = abfd;
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ptr = abfd->iovec->btell (abfd);
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while (parent_bfd->my_archive != NULL)
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{
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ptr -= parent_bfd->origin;
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parent_bfd = parent_bfd->my_archive;
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}
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}
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else
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ptr = 0;
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abfd->where = ptr;
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return ptr;
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}
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int
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bfd_flush (bfd *abfd)
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{
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if (abfd->iovec)
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return abfd->iovec->bflush (abfd);
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return 0;
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}
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/* Returns 0 for success, negative value for failure (in which case
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bfd_get_error can retrieve the error code). */
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int
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bfd_stat (bfd *abfd, struct stat *statbuf)
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{
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int result;
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if (abfd->iovec)
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result = abfd->iovec->bstat (abfd, statbuf);
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else
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result = -1;
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if (result < 0)
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bfd_set_error (bfd_error_system_call);
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return result;
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}
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/* Returns 0 for success, nonzero for failure (in which case bfd_get_error
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can retrieve the error code). */
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int
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bfd_seek (bfd *abfd, file_ptr position, int direction)
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{
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int result;
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file_ptr file_position;
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/* For the time being, a BFD may not seek to it's end. The problem
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is that we don't easily have a way to recognize the end of an
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element in an archive. */
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BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);
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if (direction == SEEK_CUR && position == 0)
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return 0;
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if (abfd->format != bfd_archive && abfd->my_archive == 0)
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{
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if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
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return 0;
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}
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else
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{
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/* We need something smarter to optimize access to archives.
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Currently, anything inside an archive is read via the file
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handle for the archive. Which means that a bfd_seek on one
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component affects the `current position' in the archive, as
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well as in any other component.
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It might be sufficient to put a spike through the cache
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abstraction, and look to the archive for the file position,
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but I think we should try for something cleaner.
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In the meantime, no optimization for archives. */
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}
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file_position = position;
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if (direction == SEEK_SET)
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{
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bfd *parent_bfd = abfd;
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while (parent_bfd->my_archive != NULL)
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{
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file_position += parent_bfd->origin;
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parent_bfd = parent_bfd->my_archive;
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}
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}
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if (abfd->iovec)
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result = abfd->iovec->bseek (abfd, file_position, direction);
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else
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result = -1;
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if (result != 0)
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{
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int hold_errno = errno;
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/* Force redetermination of `where' field. */
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bfd_tell (abfd);
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/* An EINVAL error probably means that the file offset was
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absurd. */
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if (hold_errno == EINVAL)
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bfd_set_error (bfd_error_file_truncated);
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else
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{
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bfd_set_error (bfd_error_system_call);
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errno = hold_errno;
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}
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}
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else
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{
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/* Adjust `where' field. */
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if (direction == SEEK_SET)
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abfd->where = position;
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else
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abfd->where += position;
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}
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return result;
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}
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/*
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FUNCTION
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bfd_get_mtime
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SYNOPSIS
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long bfd_get_mtime (bfd *abfd);
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DESCRIPTION
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Return the file modification time (as read from the file system, or
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from the archive header for archive members).
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*/
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long
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bfd_get_mtime (bfd *abfd)
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{
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struct stat buf;
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if (abfd->mtime_set)
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return abfd->mtime;
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if (abfd->iovec == NULL)
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return 0;
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if (abfd->iovec->bstat (abfd, &buf) != 0)
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return 0;
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abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
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return buf.st_mtime;
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}
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/*
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FUNCTION
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bfd_get_size
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SYNOPSIS
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file_ptr bfd_get_size (bfd *abfd);
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DESCRIPTION
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Return the file size (as read from file system) for the file
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associated with BFD @var{abfd}.
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The initial motivation for, and use of, this routine is not
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so we can get the exact size of the object the BFD applies to, since
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that might not be generally possible (archive members for example).
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It would be ideal if someone could eventually modify
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it so that such results were guaranteed.
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Instead, we want to ask questions like "is this NNN byte sized
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object I'm about to try read from file offset YYY reasonable?"
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As as example of where we might do this, some object formats
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use string tables for which the first <<sizeof (long)>> bytes of the
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table contain the size of the table itself, including the size bytes.
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If an application tries to read what it thinks is one of these
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string tables, without some way to validate the size, and for
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some reason the size is wrong (byte swapping error, wrong location
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for the string table, etc.), the only clue is likely to be a read
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error when it tries to read the table, or a "virtual memory
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exhausted" error when it tries to allocate 15 bazillon bytes
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of space for the 15 bazillon byte table it is about to read.
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This function at least allows us to answer the question, "is the
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size reasonable?".
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*/
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file_ptr
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bfd_get_size (bfd *abfd)
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{
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struct stat buf;
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if (abfd->iovec == NULL)
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return 0;
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if (abfd->iovec->bstat (abfd, &buf) != 0)
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return 0;
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return buf.st_size;
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}
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/*
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FUNCTION
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bfd_mmap
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SYNOPSIS
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void *bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
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int prot, int flags, file_ptr offset,
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void **map_addr, bfd_size_type *map_len);
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DESCRIPTION
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Return mmap()ed region of the file, if possible and implemented.
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LEN and OFFSET do not need to be page aligned. The page aligned
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address and length are written to MAP_ADDR and MAP_LEN.
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*/
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void *
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bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
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int prot, int flags, file_ptr offset,
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void **map_addr, bfd_size_type *map_len)
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{
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void *ret = (void *)-1;
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if (abfd->iovec == NULL)
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return ret;
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return abfd->iovec->bmmap (abfd, addr, len, prot, flags, offset,
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map_addr, map_len);
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}
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/* Memory file I/O operations. */
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static file_ptr
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memory_bread (bfd *abfd, void *ptr, file_ptr size)
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{
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struct bfd_in_memory *bim;
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bfd_size_type get;
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bim = (struct bfd_in_memory *) abfd->iostream;
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get = size;
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if (abfd->where + get > bim->size)
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{
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if (bim->size < (bfd_size_type) abfd->where)
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get = 0;
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else
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get = bim->size - abfd->where;
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bfd_set_error (bfd_error_file_truncated);
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}
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memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
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return get;
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}
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static file_ptr
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memory_bwrite (bfd *abfd, const void *ptr, file_ptr size)
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{
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struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream;
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if (abfd->where + size > bim->size)
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{
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bfd_size_type newsize, oldsize;
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oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
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bim->size = abfd->where + size;
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/* Round up to cut down on memory fragmentation */
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newsize = (bim->size + 127) & ~(bfd_size_type) 127;
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if (newsize > oldsize)
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{
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bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, newsize);
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if (bim->buffer == NULL)
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{
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bim->size = 0;
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return 0;
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}
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if (newsize > bim->size)
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memset (bim->buffer + bim->size, 0, newsize - bim->size);
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}
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}
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memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
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return size;
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}
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static file_ptr
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memory_btell (bfd *abfd)
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{
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return abfd->where;
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}
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static int
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memory_bseek (bfd *abfd, file_ptr position, int direction)
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{
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file_ptr nwhere;
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struct bfd_in_memory *bim;
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bim = (struct bfd_in_memory *) abfd->iostream;
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if (direction == SEEK_SET)
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nwhere = position;
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else
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nwhere = abfd->where + position;
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if (nwhere < 0)
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{
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abfd->where = 0;
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errno = EINVAL;
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return -1;
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}
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if ((bfd_size_type)nwhere > bim->size)
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{
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if (abfd->direction == write_direction
|
|
|| abfd->direction == both_direction)
|
|
{
|
|
bfd_size_type newsize, oldsize;
|
|
|
|
oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
|
|
bim->size = nwhere;
|
|
/* Round up to cut down on memory fragmentation */
|
|
newsize = (bim->size + 127) & ~(bfd_size_type) 127;
|
|
if (newsize > oldsize)
|
|
{
|
|
bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, newsize);
|
|
if (bim->buffer == NULL)
|
|
{
|
|
errno = EINVAL;
|
|
bim->size = 0;
|
|
return -1;
|
|
}
|
|
memset (bim->buffer + oldsize, 0, newsize - oldsize);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
abfd->where = bim->size;
|
|
errno = EINVAL;
|
|
bfd_set_error (bfd_error_file_truncated);
|
|
return -1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
memory_bclose (struct bfd *abfd)
|
|
{
|
|
struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream;
|
|
|
|
if (bim->buffer != NULL)
|
|
free (bim->buffer);
|
|
free (bim);
|
|
abfd->iostream = NULL;
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
static int
|
|
memory_bflush (bfd *abfd ATTRIBUTE_UNUSED)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
memory_bstat (bfd *abfd, struct stat *statbuf)
|
|
{
|
|
struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream;
|
|
|
|
memset (statbuf, 0, sizeof (*statbuf));
|
|
statbuf->st_size = bim->size;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void *
|
|
memory_bmmap (bfd *abfd ATTRIBUTE_UNUSED, void *addr ATTRIBUTE_UNUSED,
|
|
bfd_size_type len ATTRIBUTE_UNUSED, int prot ATTRIBUTE_UNUSED,
|
|
int flags ATTRIBUTE_UNUSED, file_ptr offset ATTRIBUTE_UNUSED,
|
|
void **map_addr ATTRIBUTE_UNUSED,
|
|
bfd_size_type *map_len ATTRIBUTE_UNUSED)
|
|
{
|
|
return (void *)-1;
|
|
}
|
|
|
|
const struct bfd_iovec _bfd_memory_iovec =
|
|
{
|
|
&memory_bread, &memory_bwrite, &memory_btell, &memory_bseek,
|
|
&memory_bclose, &memory_bflush, &memory_bstat, &memory_bmmap
|
|
};
|