-/*** cache.c -- Allows you to have more bfds open than your system has fds. */
+/* BFD library -- caching of file descriptors.
-/* Copyright (C) 1990, 1991 Free Software Foundation, Inc.
+ Copyright 1990, 1991, 1992, 1993, 1994, 1996, 2000, 2001, 2002,
+ 2003, 2004 Free Software Foundation, Inc.
-This file is part of BFD, the Binary File Diddler.
+ Hacked by Steve Chamberlain of Cygnus Support (steve@cygnus.com).
-BFD is free software; you can redistribute it and/or modify
+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 1, or (at your option)
-any later version.
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
-BFD is distributed in the hope that it will be useful,
+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 BFD; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/*
+SECTION
+ File caching
+
+ The file caching mechanism is embedded within BFD and allows
+ the application to open as many BFDs as it wants without
+ regard to the underlying operating system's file descriptor
+ limit (often as low as 20 open files). The module in
+ <<cache.c>> maintains a least recently used list of
+ <<BFD_CACHE_MAX_OPEN>> files, and exports the name
+ <<bfd_cache_lookup>>, which runs around and makes sure that
+ the required BFD is open. If not, then it chooses a file to
+ close, closes it and opens the one wanted, returning its file
+ handle.
+
+*/
-/* $Id$ */
-#include "sysdep.h"
#include "bfd.h"
+#include "sysdep.h"
#include "libbfd.h"
+#include "libiberty.h"
-/* These declarations should not be needed; libbfd.h's inclusion should
- have handled it.
- int fclose();
- int fseek();
-*/
+static bfd_boolean bfd_cache_delete (bfd *);
-/* The maximum number of FDs opened by bfd */
-#define BFD_CACHE_MAX_OPEN 10
+static file_ptr
+cache_btell (struct bfd *abfd)
+{
+ return real_ftell (bfd_cache_lookup (abfd));
+}
-/* when this exceeds BFD_CACHE_MAX_OPEN, we get to work */
-static int open_files;
+static int
+cache_bseek (struct bfd *abfd, file_ptr offset, int whence)
+{
+ return real_fseek (bfd_cache_lookup (abfd), offset, whence);
+}
-static bfd *cache_sentinel; /* Chain of bfds with active fds we've
- opened */
-static void
-bfd_cache_delete();
+/* 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.
-bfd *bfd_last_cache;
-\f
+ 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 void
-DEFUN_VOID(close_one)
+static file_ptr
+cache_bread (struct bfd *abfd, void *buf, file_ptr nbytes)
{
- bfd *kill = cache_sentinel;
- if (kill == 0) /* Nothing in the cache */
- return ;
+ file_ptr nread;
+ /* 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 (nbytes == 0)
+ return 0;
- /* We can only close files that want to play this game. */
- while (!kill->cacheable) {
- kill = kill->lru_prev;
- if (kill == cache_sentinel) /* Nobody wants to play */
- return ;
+#if defined (__VAX) && defined (VMS)
+ /* Apparently fread on Vax VMS does not keep the record length
+ information. */
+ nread = read (fileno (bfd_cache_lookup (abfd)), buf, nbytes);
+ /* 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. */
+ if (nread == (file_ptr)-1)
+ {
+ bfd_set_error (bfd_error_system_call);
+ return -1;
}
+#else
+ nread = fread (buf, 1, nbytes, bfd_cache_lookup (abfd));
+ /* 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. */
+ if (nread < nbytes && ferror (bfd_cache_lookup (abfd)))
+ {
+ bfd_set_error (bfd_error_system_call);
+ return -1;
+ }
+#endif
+ return nread;
+}
- kill->where = ftell((FILE *)(kill->iostream));
- bfd_cache_delete(kill);
+static file_ptr
+cache_bwrite (struct bfd *abfd, const void *where, file_ptr nbytes)
+{
+ file_ptr nwrite = fwrite (where, 1, nbytes, bfd_cache_lookup (abfd));
+ if (nwrite < nbytes && ferror (bfd_cache_lookup (abfd)))
+ {
+ bfd_set_error (bfd_error_system_call);
+ return -1;
+ }
+ return nwrite;
+}
+static int
+cache_bclose (struct bfd *abfd)
+{
+ return bfd_cache_close (abfd);
}
-/* Cuts the bfd abfd out of the chain in the cache */
-static void
-DEFUN(snip,(abfd),
- bfd *abfd)
+
+static int
+cache_bflush (struct bfd *abfd)
{
- abfd->lru_prev->lru_next = abfd->lru_next;
- abfd->lru_next->lru_prev = abfd->lru_prev;
- if (cache_sentinel == abfd) cache_sentinel = (bfd *)NULL;
+ int sts = fflush (bfd_cache_lookup (abfd));
+ if (sts < 0)
+ bfd_set_error (bfd_error_system_call);
+ return sts;
+}
+
+static int
+cache_bstat (struct bfd *abfd, struct stat *sb)
+{
+ int sts = fstat (fileno (bfd_cache_lookup (abfd)), sb);
+ if (sts < 0)
+ bfd_set_error (bfd_error_system_call);
+ return sts;
+}
+
+static const struct bfd_iovec cache_iovec = {
+ &cache_bread, &cache_bwrite, &cache_btell, &cache_bseek,
+ &cache_bclose, &cache_bflush, &cache_bstat
+};
+
+/*
+INTERNAL_FUNCTION
+ BFD_CACHE_MAX_OPEN macro
+
+DESCRIPTION
+ The maximum number of files which the cache will keep open at
+ one time.
+
+.#define BFD_CACHE_MAX_OPEN 10
+
+*/
+
+/* The number of BFD files we have open. */
+
+static int open_files;
+
+/*
+INTERNAL_FUNCTION
+ bfd_last_cache
+
+SYNOPSIS
+ extern bfd *bfd_last_cache;
+
+DESCRIPTION
+ Zero, or a pointer to the topmost BFD on the chain. This is
+ used by the <<bfd_cache_lookup>> macro in @file{libbfd.h} to
+ determine when it can avoid a function call.
+*/
+
+bfd *bfd_last_cache;
+
+/*
+ INTERNAL_FUNCTION
+ bfd_cache_lookup
+
+ DESCRIPTION
+ Check to see if the required BFD is the same as the last one
+ looked up. If so, then it can use the stream in the BFD with
+ impunity, since it can't have changed since the last lookup;
+ otherwise, it has to perform the complicated lookup function.
+
+ .#define bfd_cache_lookup(x) \
+ . ((x) == bfd_last_cache ? \
+ . (FILE *) (bfd_last_cache->iostream): \
+ . bfd_cache_lookup_worker (x))
+
+ */
+
+/* Insert a BFD into the cache. */
+
+static void
+insert (bfd *abfd)
+{
+ if (bfd_last_cache == NULL)
+ {
+ abfd->lru_next = abfd;
+ abfd->lru_prev = abfd;
+ }
+ else
+ {
+ abfd->lru_next = bfd_last_cache;
+ abfd->lru_prev = bfd_last_cache->lru_prev;
+ abfd->lru_prev->lru_next = abfd;
+ abfd->lru_next->lru_prev = abfd;
+ }
+ bfd_last_cache = abfd;
}
+/* Remove a BFD from the cache. */
+
static void
-DEFUN(bfd_cache_delete,(abfd),
- bfd *abfd)
+snip (bfd *abfd)
{
- fclose ((FILE *)(abfd->iostream));
- snip (abfd);
- abfd->iostream = NULL;
- open_files--;
- bfd_last_cache = 0;
+ abfd->lru_prev->lru_next = abfd->lru_next;
+ abfd->lru_next->lru_prev = abfd->lru_prev;
+ if (abfd == bfd_last_cache)
+ {
+ bfd_last_cache = abfd->lru_next;
+ if (abfd == bfd_last_cache)
+ bfd_last_cache = NULL;
+ }
}
-
-static bfd *
-DEFUN(insert,(x,y),
- bfd *x AND
- bfd *y)
+
+/* We need to open a new file, and the cache is full. Find the least
+ recently used cacheable BFD and close it. */
+
+static bfd_boolean
+close_one (void)
{
- if (y) {
- x->lru_next = y;
- x->lru_prev = y->lru_prev;
- y->lru_prev->lru_next = x;
- y->lru_prev = x;
+ register bfd *kill;
- }
- else {
- x->lru_prev = x;
- x->lru_next = x;
- }
- return x;
+ if (bfd_last_cache == NULL)
+ kill = NULL;
+ else
+ {
+ for (kill = bfd_last_cache->lru_prev;
+ ! kill->cacheable;
+ kill = kill->lru_prev)
+ {
+ if (kill == bfd_last_cache)
+ {
+ kill = NULL;
+ break;
+ }
+ }
+ }
+
+ if (kill == NULL)
+ {
+ /* There are no open cacheable BFD's. */
+ return TRUE;
+ }
+
+ kill->where = real_ftell ((FILE *) kill->iostream);
+
+ return bfd_cache_delete (kill);
}
-\f
-/* Initialize a BFD by putting it on the cache LRU. */
-void
-DEFUN(bfd_cache_init,(abfd),
- bfd *abfd)
+/* Close a BFD and remove it from the cache. */
+
+static bfd_boolean
+bfd_cache_delete (bfd *abfd)
{
- cache_sentinel = insert(abfd, cache_sentinel);
+ bfd_boolean ret;
+
+ if (fclose ((FILE *) abfd->iostream) == 0)
+ ret = TRUE;
+ else
+ {
+ ret = FALSE;
+ bfd_set_error (bfd_error_system_call);
+ }
+
+ snip (abfd);
+
+ abfd->iostream = NULL;
+ --open_files;
+
+ return ret;
}
-void
-DEFUN(bfd_cache_close,(abfd),
- bfd *abfd)
+/*
+INTERNAL_FUNCTION
+ bfd_cache_init
+
+SYNOPSIS
+ bfd_boolean bfd_cache_init (bfd *abfd);
+
+DESCRIPTION
+ Add a newly opened BFD to the cache.
+*/
+
+bfd_boolean
+bfd_cache_init (bfd *abfd)
{
- /* If this file is open then remove from the chain */
- if (abfd->iostream)
+ BFD_ASSERT (abfd->iostream != NULL);
+ if (open_files >= BFD_CACHE_MAX_OPEN)
{
- bfd_cache_delete(abfd);
+ if (! close_one ())
+ return FALSE;
}
+ abfd->iovec = &cache_iovec;
+ insert (abfd);
+ ++open_files;
+ return TRUE;
}
-\f
-/* Call the OS to open a file for this BFD. Returns the FILE *
- (possibly null) that results from this operation. Sets up the
- BFD so that future accesses know the file is open. */
+
+/*
+INTERNAL_FUNCTION
+ bfd_cache_close
+
+SYNOPSIS
+ bfd_boolean bfd_cache_close (bfd *abfd);
+
+DESCRIPTION
+ Remove the BFD @var{abfd} from the cache. If the attached file is open,
+ then close it too.
+
+RETURNS
+ <<FALSE>> is returned if closing the file fails, <<TRUE>> is
+ returned if all is well.
+*/
+
+bfd_boolean
+bfd_cache_close (bfd *abfd)
+{
+ if (abfd->iovec != &cache_iovec)
+ return TRUE;
+
+ if (abfd->iostream == NULL)
+ /* Previously closed. */
+ return TRUE;
+
+ return bfd_cache_delete (abfd);
+}
+
+/*
+FUNCTION
+ bfd_cache_close_all
+
+SYNOPSIS
+ bfd_boolean bfd_cache_close_all (void);
+
+DESCRIPTION
+ Remove all BFDs from the cache. If the attached file is open,
+ then close it too.
+
+RETURNS
+ <<FALSE>> is returned if closing one of the file fails, <<TRUE>> is
+ returned if all is well.
+*/
+
+bfd_boolean
+bfd_cache_close_all ()
+{
+ bfd_boolean ret = TRUE;
+
+ while (bfd_last_cache != NULL)
+ ret &= bfd_cache_close (bfd_last_cache);
+
+ return ret;
+}
+
+/*
+INTERNAL_FUNCTION
+ bfd_open_file
+
+SYNOPSIS
+ FILE* bfd_open_file (bfd *abfd);
+
+DESCRIPTION
+ Call the OS to open a file for @var{abfd}. Return the <<FILE *>>
+ (possibly <<NULL>>) that results from this operation. Set up the
+ BFD so that future accesses know the file is open. If the <<FILE *>>
+ returned is <<NULL>>, then it won't have been put in the
+ cache, so it won't have to be removed from it.
+*/
FILE *
-DEFUN(bfd_open_file, (abfd),
- bfd *abfd)
+bfd_open_file (bfd *abfd)
{
- abfd->cacheable = true; /* Allow it to be closed later. */
- if(open_files >= BFD_CACHE_MAX_OPEN) {
- close_one();
+ abfd->cacheable = TRUE; /* Allow it to be closed later. */
+
+ if (open_files >= BFD_CACHE_MAX_OPEN)
+ {
+ if (! close_one ())
+ return NULL;
}
- switch (abfd->direction) {
- case read_direction:
- case no_direction:
- abfd->iostream = (char *) fopen(abfd->filename, "r");
- break;
- case both_direction:
- case write_direction:
- if (abfd->opened_once == true) {
- abfd->iostream = (char *) fopen(abfd->filename, "r+");
- if (!abfd->iostream) {
- abfd->iostream = (char *) fopen(abfd->filename, "w+");
- }
- } else {
- /*open for creat */
- abfd->iostream = (char *) fopen(abfd->filename, "w");
- abfd->opened_once = true;
+
+ switch (abfd->direction)
+ {
+ case read_direction:
+ case no_direction:
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_RB);
+ break;
+ case both_direction:
+ case write_direction:
+ if (abfd->opened_once)
+ {
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_RUB);
+ if (abfd->iostream == NULL)
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_WUB);
+ }
+ else
+ {
+ /* Create the file.
+
+ Some operating systems won't let us overwrite a running
+ binary. For them, we want to unlink the file first.
+
+ However, gcc 2.95 will create temporary files using
+ O_EXCL and tight permissions to prevent other users from
+ substituting other .o files during the compilation. gcc
+ will then tell the assembler to use the newly created
+ file as an output file. If we unlink the file here, we
+ open a brief window when another user could still
+ substitute a file.
+
+ So we unlink the output file if and only if it has
+ non-zero size. */
+#ifndef __MSDOS__
+ /* Don't do this for MSDOS: it doesn't care about overwriting
+ a running binary, but if this file is already open by
+ another BFD, we will be in deep trouble if we delete an
+ open file. In fact, objdump does just that if invoked with
+ the --info option. */
+ struct stat s;
+
+ if (stat (abfd->filename, &s) == 0 && s.st_size != 0)
+ unlink_if_ordinary (abfd->filename);
+#endif
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_WUB);
+ abfd->opened_once = TRUE;
}
- break;
+ break;
}
- if (abfd->iostream) {
- open_files++;
- bfd_cache_init (abfd);
+
+ if (abfd->iostream != NULL)
+ {
+ if (! bfd_cache_init (abfd))
+ return NULL;
}
- return (FILE *)(abfd->iostream);
+ return (FILE *) abfd->iostream;
}
-/* Find a file descriptor for this BFD. If necessary, open it.
- If there are already more than BFD_CACHE_MAX_OPEN files open, try to close
- one first, to avoid running out of file descriptors. */
+/*
+INTERNAL_FUNCTION
+ bfd_cache_lookup_worker
+
+SYNOPSIS
+ FILE *bfd_cache_lookup_worker (bfd *abfd);
+
+DESCRIPTION
+ Called when the macro <<bfd_cache_lookup>> fails to find a
+ quick answer. Find a file descriptor for @var{abfd}. If
+ necessary, it open it. If there are already more than
+ <<BFD_CACHE_MAX_OPEN>> files open, it tries to close one first, to
+ avoid running out of file descriptors. It will abort rather than
+ returning NULL if it is unable to (re)open the @var{abfd}.
+*/
FILE *
-DEFUN(bfd_cache_lookup_worker,(abfd),
- bfd *abfd)
-{
- if (abfd->my_archive)
- {
- abfd = abfd->my_archive;
- }
- /* Is this file already open .. if so then quick exit */
- if (abfd->iostream)
- {
- if (abfd != cache_sentinel) {
- /* Place onto head of lru chain */
+bfd_cache_lookup_worker (bfd *abfd)
+{
+ if ((abfd->flags & BFD_IN_MEMORY) != 0)
+ abort ();
+
+ if (abfd->my_archive)
+ abfd = abfd->my_archive;
+
+ if (abfd->iostream != NULL)
+ {
+ /* Move the file to the start of the cache. */
+ if (abfd != bfd_last_cache)
+ {
snip (abfd);
- cache_sentinel = insert(abfd, cache_sentinel);
+ insert (abfd);
}
- }
- /* This is a bfd without a stream -
- so it must have been closed or never opened.
- find an empty cache entry and use it. */
- else
- {
-
- if (open_files >= BFD_CACHE_MAX_OPEN)
- {
- close_one();
- }
+ }
+ else
+ {
+ if (bfd_open_file (abfd) == NULL
+ || abfd->where != (unsigned long) abfd->where
+ || real_fseek ((FILE *) abfd->iostream, abfd->where, SEEK_SET) != 0)
+ abort ();
+ }
- BFD_ASSERT(bfd_open_file (abfd) != (FILE *)NULL) ;
- fseek((FILE *)(abfd->iostream), abfd->where, false);
- }
- bfd_last_cache = abfd;
- return (FILE *)(abfd->iostream);
+ return (FILE *) abfd->iostream;
}
projects / deliverable / binutils-gdb.git / blobdiff