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binutils-gdb/bfd/bfdio.c

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/* Low-level I/O routines for BFDs.
Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011
Free Software Foundation, Inc.
Written by Cygnus Support.
This file is part of BFD, the Binary File Descriptor library.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "sysdep.h"
#include <limits.h>
#include "bfd.h"
#include "libbfd.h"
#ifndef S_IXUSR
#define S_IXUSR 0100 /* Execute by owner. */
#endif
#ifndef S_IXGRP
#define S_IXGRP 0010 /* Execute by group. */
#endif
#ifndef S_IXOTH
#define S_IXOTH 0001 /* Execute by others. */
#endif
#ifndef FD_CLOEXEC
#define FD_CLOEXEC 1
#endif
file_ptr
real_ftell (FILE *file)
{
#if defined (HAVE_FTELLO64)
return ftello64 (file);
#elif defined (HAVE_FTELLO)
return ftello (file);
#else
return ftell (file);
#endif
}
int
real_fseek (FILE *file, file_ptr offset, int whence)
{
#if defined (HAVE_FSEEKO64)
return fseeko64 (file, offset, whence);
#elif defined (HAVE_FSEEKO)
return fseeko (file, offset, whence);
#else
return fseek (file, offset, whence);
#endif
}
/* Mark FILE as close-on-exec. Return FILE. FILE may be NULL, in
which case nothing is done. */
static FILE *
close_on_exec (FILE *file)
{
#if defined (HAVE_FILENO) && defined (F_GETFD)
if (file)
{
int fd = fileno (file);
int old = fcntl (fd, F_GETFD, 0);
if (old >= 0)
fcntl (fd, F_SETFD, old | FD_CLOEXEC);
}
#endif
return file;
}
FILE *
real_fopen (const char *filename, const char *modes)
{
#ifdef VMS
char vms_modes[4];
char *vms_attr;
/* On VMS, fopen allows file attributes as optionnal arguments.
We need to use them but we'd better to use the common prototype.
In fopen-vms.h, they are separated from the mode with a comma.
Split here. */
vms_attr = strchr (modes, ',');
if (vms_attr == NULL)
{
/* No attributes. */
return close_on_exec (fopen (filename, modes));
}
else
{
/* Attributes found. Split. */
size_t modes_len = strlen (modes) + 1;
char attrs[modes_len + 1];
char *at[3];
int i;
memcpy (attrs, modes, modes_len);
at[0] = attrs;
for (i = 0; i < 2; i++)
{
at[i + 1] = strchr (at[i], ',');
BFD_ASSERT (at[i + 1] != NULL);
*(at[i + 1]++) = 0; /* Replace ',' with a nul, and skip it. */
}
return close_on_exec (fopen (filename, at[0], at[1], at[2]));
}
#else /* !VMS */
#if defined (HAVE_FOPEN64)
return close_on_exec (fopen64 (filename, modes));
#else
return close_on_exec (fopen (filename, modes));
#endif
#endif /* !VMS */
}
/*
INTERNAL_DEFINITION
struct bfd_iovec
DESCRIPTION
The <<struct bfd_iovec>> contains the internal file I/O class.
Each <<BFD>> has an instance of this class and all file I/O is
routed through it (it is assumed that the instance implements
all methods listed below).
.struct bfd_iovec
.{
. {* To avoid problems with macros, a "b" rather than "f"
. prefix is prepended to each method name. *}
. {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
. bytes starting at PTR. Return the number of bytes actually
. transfered (a read past end-of-file returns less than NBYTES),
. or -1 (setting <<bfd_error>>) if an error occurs. *}
. file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
. file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
. file_ptr nbytes);
. {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
. if an error occurs. *}
. file_ptr (*btell) (struct bfd *abfd);
. {* For the following, on successful completion a value of 0 is returned.
. Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *}
. int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
. int (*bclose) (struct bfd *abfd);
. int (*bflush) (struct bfd *abfd);
. int (*bstat) (struct bfd *abfd, struct stat *sb);
. {* Mmap a part of the files. ADDR, LEN, PROT, FLAGS and OFFSET are the usual
. mmap parameter, except that LEN and OFFSET do not need to be page
. aligned. Returns (void *)-1 on failure, mmapped address on success.
. Also write in MAP_ADDR the address of the page aligned buffer and in
. MAP_LEN the size mapped (a page multiple). Use unmap with MAP_ADDR and
. MAP_LEN to unmap. *}
. void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
. int prot, int flags, file_ptr offset,
. void **map_addr, bfd_size_type *map_len);
.};
.extern const struct bfd_iovec _bfd_memory_iovec;
*/
/* Return value is amount read. */
bfd_size_type
bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
{
size_t nread;
/* If this is an archive element, don't read past the end of
this element. */
if (abfd->arelt_data != NULL)
{
size_t maxbytes = ((struct areltdata *) abfd->arelt_data)->parsed_size;
if (abfd->where + size > maxbytes)
{
if (abfd->where >= maxbytes)
return 0;
size = maxbytes - abfd->where;
}
}
if (abfd->iovec)
nread = abfd->iovec->bread (abfd, ptr, size);
else
nread = 0;
if (nread != (size_t) -1)
abfd->where += nread;
return nread;
}
bfd_size_type
bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
{
size_t nwrote;
if (abfd->iovec)
nwrote = abfd->iovec->bwrite (abfd, ptr, size);
else
nwrote = 0;
if (nwrote != (size_t) -1)
abfd->where += nwrote;
if (nwrote != size)
{
#ifdef ENOSPC
errno = ENOSPC;
#endif
bfd_set_error (bfd_error_system_call);
}
return nwrote;
}
file_ptr
bfd_tell (bfd *abfd)
{
file_ptr ptr;
if (abfd->iovec)
{
ptr = abfd->iovec->btell (abfd);
if (abfd->my_archive)
ptr -= abfd->origin;
}
else
ptr = 0;
abfd->where = ptr;
return ptr;
}
int
bfd_flush (bfd *abfd)
{
if (abfd->iovec)
return abfd->iovec->bflush (abfd);
return 0;
}
/* Returns 0 for success, negative value for failure (in which case
bfd_get_error can retrieve the error code). */
int
bfd_stat (bfd *abfd, struct stat *statbuf)
{
int result;
if (abfd->iovec)
result = abfd->iovec->bstat (abfd, statbuf);
else
result = -1;
if (result < 0)
bfd_set_error (bfd_error_system_call);
return result;
}
/* Returns 0 for success, nonzero for failure (in which case bfd_get_error
can retrieve the error code). */
int
bfd_seek (bfd *abfd, file_ptr position, int direction)
{
int result;
file_ptr file_position;
/* For the time being, a BFD may not seek to it's end. The problem
is that we don't easily have a way to recognize the end of an
element in an archive. */
BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);
if (direction == SEEK_CUR && position == 0)
return 0;
if (abfd->format != bfd_archive && abfd->my_archive == 0)
{
if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
return 0;
}
else
{
/* We need something smarter to optimize access to archives.
Currently, anything inside an archive is read via the file
handle for the archive. Which means that a bfd_seek on one
component affects the `current position' in the archive, as
well as in any other component.
It might be sufficient to put a spike through the cache
abstraction, and look to the archive for the file position,
but I think we should try for something cleaner.
In the meantime, no optimization for archives. */
}
file_position = position;
if (direction == SEEK_SET && abfd->my_archive != NULL)
file_position += abfd->origin;
if (abfd->iovec)
result = abfd->iovec->bseek (abfd, file_position, direction);
else
result = -1;
if (result != 0)
{
int hold_errno = errno;
/* Force redetermination of `where' field. */
bfd_tell (abfd);
/* An EINVAL error probably means that the file offset was
absurd. */
if (hold_errno == EINVAL)
bfd_set_error (bfd_error_file_truncated);
else
{
bfd_set_error (bfd_error_system_call);
errno = hold_errno;
}
}
else
{
/* Adjust `where' field. */
if (direction == SEEK_SET)
abfd->where = position;
else
abfd->where += position;
}
return result;
}
/*
FUNCTION
bfd_get_mtime
SYNOPSIS
long bfd_get_mtime (bfd *abfd);
DESCRIPTION
Return the file modification time (as read from the file system, or
from the archive header for archive members).
*/
long
bfd_get_mtime (bfd *abfd)
{
struct stat buf;
if (abfd->mtime_set)
return abfd->mtime;
if (abfd->iovec == NULL)
return 0;
if (abfd->iovec->bstat (abfd, &buf) != 0)
return 0;
abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
return buf.st_mtime;
}
/*
FUNCTION
bfd_get_size
SYNOPSIS
file_ptr bfd_get_size (bfd *abfd);
DESCRIPTION
Return the file size (as read from file system) for the file
associated with BFD @var{abfd}.
The initial motivation for, and use of, this routine is not
so we can get the exact size of the object the BFD applies to, since
that might not be generally possible (archive members for example).
It would be ideal if someone could eventually modify
it so that such results were guaranteed.
Instead, we want to ask questions like "is this NNN byte sized
object I'm about to try read from file offset YYY reasonable?"
As as example of where we might do this, some object formats
use string tables for which the first <<sizeof (long)>> bytes of the
table contain the size of the table itself, including the size bytes.
If an application tries to read what it thinks is one of these
string tables, without some way to validate the size, and for
some reason the size is wrong (byte swapping error, wrong location
for the string table, etc.), the only clue is likely to be a read
error when it tries to read the table, or a "virtual memory
exhausted" error when it tries to allocate 15 bazillon bytes
of space for the 15 bazillon byte table it is about to read.
This function at least allows us to answer the question, "is the
size reasonable?".
*/
file_ptr
bfd_get_size (bfd *abfd)
{
struct stat buf;
if (abfd->iovec == NULL)
return 0;
if (abfd->iovec->bstat (abfd, &buf) != 0)
return 0;
return buf.st_size;
}
/*
FUNCTION
bfd_mmap
SYNOPSIS
void *bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
int prot, int flags, file_ptr offset,
void **map_addr, bfd_size_type *map_len);
DESCRIPTION
Return mmap()ed region of the file, if possible and implemented.
LEN and OFFSET do not need to be page aligned. The page aligned
address and length are written to MAP_ADDR and MAP_LEN.
*/
void *
bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
int prot, int flags, file_ptr offset,
void **map_addr, bfd_size_type *map_len)
{
void *ret = (void *)-1;
if (abfd->iovec == NULL)
return ret;
return abfd->iovec->bmmap (abfd, addr, len, prot, flags, offset,
map_addr, map_len);
}
/* Memory file I/O operations. */
static file_ptr
memory_bread (bfd *abfd, void *ptr, file_ptr size)
{
struct bfd_in_memory *bim;
bfd_size_type get;
bim = (struct bfd_in_memory *) abfd->iostream;
get = size;
if (abfd->where + get > bim->size)
{
if (bim->size < (bfd_size_type) abfd->where)
get = 0;
else
get = bim->size - abfd->where;
bfd_set_error (bfd_error_file_truncated);
}
memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
return get;
}
static file_ptr
memory_bwrite (bfd *abfd, const void *ptr, file_ptr size)
{
struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream;
if (abfd->where + size > bim->size)
{
bfd_size_type newsize, oldsize;
oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
bim->size = abfd->where + size;
/* 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)
{
bim->size = 0;
return 0;
}
if (newsize > bim->size)
memset (bim->buffer + bim->size, 0, newsize - bim->size);
}
}
memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
return size;
}
static file_ptr
memory_btell (bfd *abfd)
{
return abfd->where;
}
static int
memory_bseek (bfd *abfd, file_ptr position, int direction)
{
file_ptr nwhere;
struct bfd_in_memory *bim;
bim = (struct bfd_in_memory *) abfd->iostream;
if (direction == SEEK_SET)
nwhere = position;
else
nwhere = abfd->where + position;
if (nwhere < 0)
{
abfd->where = 0;
errno = EINVAL;
return -1;
}
if ((bfd_size_type)nwhere > bim->size)
{
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
};
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