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Diffstat (limited to 'bfd/bfdio.c')
| -rw-r--r-- | bfd/bfdio.c | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/bfd/bfdio.c b/bfd/bfdio.c new file mode 100644 index 0000000..3229316 --- /dev/null +++ b/bfd/bfdio.c @@ -0,0 +1,436 @@ +/* Low-level I/O routines for BFDs. + Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, + 2000, 2001, 2002 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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +#include "sysdep.h" + +#include "bfd.h" +#include "libbfd.h" + +#include <limits.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 + +/* Note that archive entries don't have streams; they share their parent's. + This allows someone to play with the iostream behind BFD's back. + + Also, note that the origin pointer points to the beginning of a file's + contents (0 for non-archive elements). For archive entries this is the + first octet in the file, NOT the beginning of the archive header. */ + +static size_t real_read PARAMS ((PTR where, size_t a, size_t b, FILE *file)); +static size_t +real_read (where, a, b, file) + PTR where; + size_t a; + size_t b; + FILE *file; +{ + /* FIXME - this looks like an optimization, but it's really to cover + up for a feature of some OSs (not solaris - sigh) that + ld/pe-dll.c takes advantage of (apparently) when it creates BFDs + internally and tries to link against them. BFD seems to be smart + enough to realize there are no symbol records in the "file" that + doesn't exist but attempts to read them anyway. On Solaris, + attempting to read zero bytes from a NULL file results in a core + dump, but on other platforms it just returns zero bytes read. + This makes it to something reasonable. - DJ */ + if (a == 0 || b == 0) + return 0; + + +#if defined (__VAX) && defined (VMS) + /* Apparently fread on Vax VMS does not keep the record length + information. */ + return read (fileno (file), where, a * b); +#else + return fread (where, a, b, file); +#endif +} + +/* Return value is amount read. */ + +bfd_size_type +bfd_bread (ptr, size, abfd) + PTR ptr; + bfd_size_type size; + bfd *abfd; +{ + size_t nread; + + if ((abfd->flags & BFD_IN_MEMORY) != 0) + { + 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); + abfd->where += get; + return get; + } + + nread = real_read (ptr, 1, (size_t) size, bfd_cache_lookup (abfd)); + if (nread != (size_t) -1) + abfd->where += nread; + + /* Set bfd_error if we did not read as much data as we expected. + + If the read failed due to an error set the bfd_error_system_call, + else set bfd_error_file_truncated. + + A BFD backend may wish to override bfd_error_file_truncated to + provide something more useful (eg. no_symbols or wrong_format). */ + if (nread != size) + { + if (ferror (bfd_cache_lookup (abfd))) + bfd_set_error (bfd_error_system_call); + else + bfd_set_error (bfd_error_file_truncated); + } + + return nread; +} + +bfd_size_type +bfd_bwrite (ptr, size, abfd) + const PTR ptr; + bfd_size_type size; + bfd *abfd; +{ + size_t nwrote; + + if ((abfd->flags & BFD_IN_MEMORY) != 0) + { + struct bfd_in_memory *bim = (struct bfd_in_memory *) (abfd->iostream); + size = (size_t) size; + 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 (bim->buffer, newsize); + if (bim->buffer == 0) + { + bim->size = 0; + return 0; + } + } + } + memcpy (bim->buffer + abfd->where, ptr, (size_t) size); + abfd->where += size; + return size; + } + + nwrote = fwrite (ptr, 1, (size_t) size, bfd_cache_lookup (abfd)); + 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; +} + +bfd_vma +bfd_tell (abfd) + bfd *abfd; +{ + file_ptr ptr; + + if ((abfd->flags & BFD_IN_MEMORY) != 0) + return abfd->where; + + ptr = ftell (bfd_cache_lookup (abfd)); + + if (abfd->my_archive) + ptr -= abfd->origin; + abfd->where = ptr; + return ptr; +} + +int +bfd_flush (abfd) + bfd *abfd; +{ + if ((abfd->flags & BFD_IN_MEMORY) != 0) + return 0; + return fflush (bfd_cache_lookup(abfd)); +} + +/* Returns 0 for success, negative value for failure (in which case + bfd_get_error can retrieve the error code). */ +int +bfd_stat (abfd, statbuf) + bfd *abfd; + struct stat *statbuf; +{ + FILE *f; + int result; + + if ((abfd->flags & BFD_IN_MEMORY) != 0) + abort (); + + f = bfd_cache_lookup (abfd); + if (f == NULL) + { + bfd_set_error (bfd_error_system_call); + return -1; + } + result = fstat (fileno (f), statbuf); + 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 (abfd, position, direction) + bfd *abfd; + file_ptr position; + int direction; +{ + int result; + FILE *f; + long 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->flags & BFD_IN_MEMORY) != 0) + { + struct bfd_in_memory *bim; + + bim = (struct bfd_in_memory *) abfd->iostream; + + if (direction == SEEK_SET) + abfd->where = position; + else + abfd->where += position; + + if (abfd->where > 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 = abfd->where; + /* 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 (bim->buffer, newsize); + if (bim->buffer == 0) + { + bim->size = 0; + return -1; + } + } + } + else + { + abfd->where = bim->size; + bfd_set_error (bfd_error_file_truncated); + return -1; + } + } + return 0; + } + + if (abfd->format != bfd_archive && abfd->my_archive == 0) + { +#if 0 + /* Explanation for this code: I'm only about 95+% sure that the above + conditions are sufficient and that all i/o calls are properly + adjusting the `where' field. So this is sort of an `assert' + that the `where' field is correct. If we can go a while without + tripping the abort, we can probably safely disable this code, + so that the real optimizations happen. */ + file_ptr where_am_i_now; + where_am_i_now = ftell (bfd_cache_lookup (abfd)); + if (abfd->my_archive) + where_am_i_now -= abfd->origin; + if (where_am_i_now != abfd->where) + abort (); +#endif + 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. */ + } + + f = bfd_cache_lookup (abfd); + file_position = position; + if (direction == SEEK_SET && abfd->my_archive != NULL) + file_position += abfd->origin; + + result = fseek (f, file_position, direction); + 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 (abfd) + bfd *abfd; +{ + FILE *fp; + struct stat buf; + + if (abfd->mtime_set) + return abfd->mtime; + + fp = bfd_cache_lookup (abfd); + if (0 != fstat (fileno (fp), &buf)) + return 0; + + abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ + return buf.st_mtime; +} + +/* +FUNCTION + bfd_get_size + +SYNOPSIS + long 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 quesion, "is the + size reasonable?". +*/ + +long +bfd_get_size (abfd) + bfd *abfd; +{ + FILE *fp; + struct stat buf; + + if ((abfd->flags & BFD_IN_MEMORY) != 0) + return ((struct bfd_in_memory *) abfd->iostream)->size; + + fp = bfd_cache_lookup (abfd); + if (0 != fstat (fileno (fp), & buf)) + return 0; + + return buf.st_size; +} |