-
/* BFD library -- caching of file descriptors.
- Copyright (C) 1990-1991 Free Software Foundation, Inc.
+
+ Copyright (C) 1990-2014 Free Software Foundation, Inc.
+
Hacked by Steve Chamberlain of Cygnus Support (steve@cygnus.com).
-This file is part of BFD, the Binary File Descriptor library.
+ 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 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.
+ 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
+ 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. */
/*
SECTION
- File Caching
+ 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
+ <<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.
+ handle.
+SUBSECTION
+ Caching functions
*/
-/* $Id$ */
-
-#include "bfd.h"
#include "sysdep.h"
+#include "bfd.h"
#include "libbfd.h"
+#include "libiberty.h"
+#include "bfd_stdint.h"
+
+#ifdef HAVE_MMAP
+#include <sys/mman.h>
+#endif
+
+/* In some cases we can optimize cache operation when reopening files.
+ For instance, a flush is entirely unnecessary if the file is already
+ closed, so a flush would use CACHE_NO_OPEN. Similarly, a seek using
+ SEEK_SET or SEEK_END need not first seek to the current position.
+ For stat we ignore seek errors, just in case the file has changed
+ while we weren't looking. If it has, then it's possible that the
+ file is shorter and we don't want a seek error to prevent us doing
+ the stat. */
+enum cache_flag {
+ CACHE_NORMAL = 0,
+ CACHE_NO_OPEN = 1,
+ CACHE_NO_SEEK = 2,
+ CACHE_NO_SEEK_ERROR = 4
+};
+
+/* The maximum number of files which the cache will keep open at
+ one time. When needed call bfd_cache_max_open to initialize. */
+
+static int max_open_files = 0;
+
+/* Set max_open_files, if not already set, to 12.5% of the allowed open
+ file descriptors, but at least 10, and return the value. */
+static int
+bfd_cache_max_open (void)
+{
+ if (max_open_files == 0)
+ {
+ int max;
+#ifdef HAVE_GETRLIMIT
+ struct rlimit rlim;
+ if (getrlimit (RLIMIT_NOFILE, &rlim) == 0
+ && rlim.rlim_cur != (rlim_t) RLIM_INFINITY)
+ max = rlim.rlim_cur / 8;
+ else
+#endif /* HAVE_GETRLIMIT */
+#ifdef _SC_OPEN_MAX
+ max = sysconf (_SC_OPEN_MAX) / 8;
+#else
+ max = 10;
+#endif /* _SC_OPEN_MAX */
+ max_open_files = max < 10 ? 10 : max;
+ }
-/*
-INTERNAL_FUNCTION
- BFD_CACHE_MAX_OPEN macro
+ return max_open_files;
+}
-DESCRIPTION
- The maxiumum number of files which the cache will keep open at
- one time.
+/* The number of BFD files we have open. */
-.#define BFD_CACHE_MAX_OPEN 10
+static int open_files;
-*/
+/* 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. */
+static bfd *bfd_last_cache = NULL;
-static int open_files;
+/* Insert a BFD into the cache. */
-static bfd *cache_sentinel; /* Chain of BFDs with active fds we've
- opened */
+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;
+}
-/*
-INTERNAL_FUNCTION
- bfd_last_cache
+/* Remove a BFD from the cache. */
-SYNOPSIS
- extern bfd *bfd_last_cache;
+static void
+snip (bfd *abfd)
+{
+ 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;
+ }
+}
-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.
-*/
+/* Close a BFD and remove it from the cache. */
-bfd *bfd_last_cache;
+static bfd_boolean
+bfd_cache_delete (bfd *abfd)
+{
+ bfd_boolean ret;
-/*
- * INTERNAL_FUNCTION
- * bfd_cache_lookup
- *
- * DESCRIPTION
- * Checks to see if the required BFD is the same as the last one
- * looked up. If so then it can use the iostream 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))
- *
- *
- */
-
-static void bfd_cache_delete();
+ if (fclose ((FILE *) abfd->iostream) == 0)
+ ret = TRUE;
+ else
+ {
+ ret = FALSE;
+ bfd_set_error (bfd_error_system_call);
+ }
+ snip (abfd);
-static void
-DEFUN_VOID(close_one)
+ abfd->iostream = NULL;
+ --open_files;
+
+ return ret;
+}
+
+/* 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)
{
- bfd *kill = cache_sentinel;
- if (kill == 0) /* Nothing in the cache */
- return ;
-
- /* 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 ;
+ register bfd *to_kill;
+
+ if (bfd_last_cache == NULL)
+ to_kill = NULL;
+ else
+ {
+ for (to_kill = bfd_last_cache->lru_prev;
+ ! to_kill->cacheable;
+ to_kill = to_kill->lru_prev)
+ {
+ if (to_kill == bfd_last_cache)
+ {
+ to_kill = NULL;
+ break;
+ }
+ }
}
- kill->where = ftell((FILE *)(kill->iostream));
- bfd_cache_delete(kill);
+ if (to_kill == NULL)
+ {
+ /* There are no open cacheable BFD's. */
+ return TRUE;
+ }
+
+ to_kill->where = real_ftell ((FILE *) to_kill->iostream);
+
+ return bfd_cache_delete (to_kill);
}
-/* Cuts the BFD abfd out of the chain in the cache */
-static void
-DEFUN(snip,(abfd),
- bfd *abfd)
+/* 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, flag) \
+ ((x) == bfd_last_cache \
+ ? (FILE *) (bfd_last_cache->iostream) \
+ : bfd_cache_lookup_worker (x, flag))
+
+/* 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 return NULL
+ if it is unable to (re)open the @var{abfd}. */
+
+static FILE *
+bfd_cache_lookup_worker (bfd *abfd, enum cache_flag flag)
{
- abfd->lru_prev->lru_next = abfd->lru_next;
- abfd->lru_next->lru_prev = abfd->lru_prev;
- if (cache_sentinel == abfd) cache_sentinel = (bfd *)NULL;
+ bfd *orig_bfd = abfd;
+ if ((abfd->flags & BFD_IN_MEMORY) != 0)
+ abort ();
+
+ while (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);
+ insert (abfd);
+ }
+ return (FILE *) abfd->iostream;
+ }
+
+ if (flag & CACHE_NO_OPEN)
+ return NULL;
+
+ if (bfd_open_file (abfd) == NULL)
+ ;
+ else if (!(flag & CACHE_NO_SEEK)
+ && real_fseek ((FILE *) abfd->iostream, abfd->where, SEEK_SET) != 0
+ && !(flag & CACHE_NO_SEEK_ERROR))
+ bfd_set_error (bfd_error_system_call);
+ else
+ return (FILE *) abfd->iostream;
+
+ (*_bfd_error_handler) (_("reopening %B: %s\n"),
+ orig_bfd, bfd_errmsg (bfd_get_error ()));
+ return NULL;
}
-static void
-DEFUN(bfd_cache_delete,(abfd),
- bfd *abfd)
+static file_ptr
+cache_btell (struct bfd *abfd)
{
- fclose ((FILE *)(abfd->iostream));
- snip (abfd);
- abfd->iostream = NULL;
- open_files--;
- bfd_last_cache = 0;
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NO_OPEN);
+ if (f == NULL)
+ return abfd->where;
+ return real_ftell (f);
}
-
-static bfd *
-DEFUN(insert,(x,y),
- bfd *x AND
- bfd *y)
+
+static int
+cache_bseek (struct bfd *abfd, file_ptr offset, int whence)
{
- if (y) {
- x->lru_next = y;
- x->lru_prev = y->lru_prev;
- y->lru_prev->lru_next = x;
- y->lru_prev = x;
-
- }
- else {
- x->lru_prev = x;
- x->lru_next = x;
- }
- return x;
+ FILE *f = bfd_cache_lookup (abfd, whence != SEEK_CUR ? CACHE_NO_SEEK : CACHE_NORMAL);
+ if (f == NULL)
+ return -1;
+ return real_fseek (f, offset, whence);
+}
+
+/* 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 file_ptr
+cache_bread_1 (struct bfd *abfd, void *buf, file_ptr nbytes)
+{
+ FILE *f;
+ 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;
+
+ f = bfd_cache_lookup (abfd, CACHE_NORMAL);
+ if (f == NULL)
+ return 0;
+
+#if defined (__VAX) && defined (VMS)
+ /* Apparently fread on Vax VMS does not keep the record length
+ information. */
+ nread = read (fileno (f), 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, f);
+ /* 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 (f))
+ {
+ bfd_set_error (bfd_error_system_call);
+ return -1;
+ }
+#endif
+ if (nread < nbytes)
+ /* This may or may not be an error, but in case the calling code
+ bails out because of it, set the right error code. */
+ bfd_set_error (bfd_error_file_truncated);
+ return nread;
}
-\f
+
+static file_ptr
+cache_bread (struct bfd *abfd, void *buf, file_ptr nbytes)
+{
+ file_ptr nread = 0;
+
+ /* Some filesystems are unable to handle reads that are too large
+ (for instance, NetApp shares with oplocks turned off). To avoid
+ hitting this limitation, we read the buffer in chunks of 8MB max. */
+ while (nread < nbytes)
+ {
+ const file_ptr max_chunk_size = 0x800000;
+ file_ptr chunk_size = nbytes - nread;
+ file_ptr chunk_nread;
+
+ if (chunk_size > max_chunk_size)
+ chunk_size = max_chunk_size;
+
+ chunk_nread = cache_bread_1 (abfd, (char *) buf + nread, chunk_size);
+
+ /* Update the nread count.
+
+ We just have to be careful of the case when cache_bread_1 returns
+ a negative count: If this is our first read, then set nread to
+ that negative count in order to return that negative value to the
+ caller. Otherwise, don't add it to our total count, or we would
+ end up returning a smaller number of bytes read than we actually
+ did. */
+ if (nread == 0 || chunk_nread > 0)
+ nread += chunk_nread;
+
+ if (chunk_nread < chunk_size)
+ break;
+ }
+
+ return nread;
+}
+
+static file_ptr
+cache_bwrite (struct bfd *abfd, const void *where, file_ptr nbytes)
+{
+ file_ptr nwrite;
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NORMAL);
+
+ if (f == NULL)
+ return 0;
+ nwrite = fwrite (where, 1, nbytes, f);
+ if (nwrite < nbytes && ferror (f))
+ {
+ bfd_set_error (bfd_error_system_call);
+ return -1;
+ }
+ return nwrite;
+}
+
+static int
+cache_bclose (struct bfd *abfd)
+{
+ return bfd_cache_close (abfd) - 1;
+}
+
+static int
+cache_bflush (struct bfd *abfd)
+{
+ int sts;
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NO_OPEN);
+
+ if (f == NULL)
+ return 0;
+ sts = fflush (f);
+ if (sts < 0)
+ bfd_set_error (bfd_error_system_call);
+ return sts;
+}
+
+static int
+cache_bstat (struct bfd *abfd, struct stat *sb)
+{
+ int sts;
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NO_SEEK_ERROR);
+
+ if (f == NULL)
+ return -1;
+ sts = fstat (fileno (f), sb);
+ if (sts < 0)
+ bfd_set_error (bfd_error_system_call);
+ return sts;
+}
+
+static void *
+cache_bmmap (struct 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)
+{
+ void *ret = (void *) -1;
+
+ if ((abfd->flags & BFD_IN_MEMORY) != 0)
+ abort ();
+#ifdef HAVE_MMAP
+ else
+ {
+ static uintptr_t pagesize_m1;
+ FILE *f;
+ file_ptr pg_offset;
+ bfd_size_type pg_len;
+
+ f = bfd_cache_lookup (abfd, CACHE_NO_SEEK_ERROR);
+ if (f == NULL)
+ return ret;
+
+ if (pagesize_m1 == 0)
+ pagesize_m1 = getpagesize () - 1;
+
+ /* Handle archive members. */
+ if (abfd->my_archive != NULL)
+ offset += abfd->origin;
+
+ /* Align. */
+ pg_offset = offset & ~pagesize_m1;
+ pg_len = (len + (offset - pg_offset) + pagesize_m1) & ~pagesize_m1;
+
+ ret = mmap (addr, pg_len, prot, flags, fileno (f), pg_offset);
+ if (ret == (void *) -1)
+ bfd_set_error (bfd_error_system_call);
+ else
+ {
+ *map_addr = ret;
+ *map_len = pg_len;
+ ret = (char *) ret + (offset & pagesize_m1);
+ }
+ }
+#endif
+
+ return ret;
+}
+
+static const struct bfd_iovec cache_iovec =
+{
+ &cache_bread, &cache_bwrite, &cache_btell, &cache_bseek,
+ &cache_bclose, &cache_bflush, &cache_bstat, &cache_bmmap
+};
/*
INTERNAL_FUNCTION
bfd_cache_init
SYNOPSIS
- void bfd_cache_init (bfd *);
+ bfd_boolean bfd_cache_init (bfd *abfd);
DESCRIPTION
- Initialize a BFD by putting it on the cache LRU.
+ Add a newly opened BFD to the cache.
*/
-void
-DEFUN(bfd_cache_init,(abfd),
- bfd *abfd)
+bfd_boolean
+bfd_cache_init (bfd *abfd)
{
- cache_sentinel = insert(abfd, cache_sentinel);
+ BFD_ASSERT (abfd->iostream != NULL);
+ if (open_files >= bfd_cache_max_open ())
+ {
+ if (! close_one ())
+ return FALSE;
+ }
+ abfd->iovec = &cache_iovec;
+ insert (abfd);
+ ++open_files;
+ return TRUE;
}
-
/*
INTERNAL_FUNCTION
bfd_cache_close
+SYNOPSIS
+ bfd_boolean bfd_cache_close (bfd *abfd);
+
DESCRIPTION
- Remove the BFD from the cache. If the attached file is open,
+ Remove the BFD @var{abfd} from the cache. If the attached file is open,
then close it too.
-SYNOPSIS
- void bfd_cache_close (bfd *);
+RETURNS
+ <<FALSE>> is returned if closing the file fails, <<TRUE>> is
+ returned if all is well.
*/
-void
-DEFUN(bfd_cache_close,(abfd),
- bfd *abfd)
+
+bfd_boolean
+bfd_cache_close (bfd *abfd)
{
- /* If this file is open then remove from the chain */
- if (abfd->iostream)
- {
- bfd_cache_delete(abfd);
- }
+ if (abfd->iovec != &cache_iovec)
+ return TRUE;
+
+ if (abfd->iostream == NULL)
+ /* Previously closed. */
+ return TRUE;
+
+ return bfd_cache_delete (abfd);
}
/*
-INTERNAL_FUNCTION
- bfd_open_file
+FUNCTION
+ bfd_cache_close_all
+
+SYNOPSIS
+ bfd_boolean bfd_cache_close_all (void);
DESCRIPTION
- 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. If the FILE
- * returned is null, then there is won't have been put in the
- cache, so it won't have to be removed from it.
+ Remove all BFDs from the cache. If the attached file is open,
+ then close it too.
-SYNOPSIS
- FILE* bfd_open_file(bfd *);
+RETURNS
+ <<FALSE>> is returned if closing one of the file fails, <<TRUE>> is
+ returned if all is well.
*/
-FILE *
-DEFUN(bfd_open_file, (abfd),
- bfd *abfd)
+bfd_boolean
+bfd_cache_close_all ()
{
- abfd->cacheable = true; /* Allow it to be closed later. */
-
- if(open_files >= BFD_CACHE_MAX_OPEN) {
- close_one();
- }
-
- switch (abfd->direction) {
- case read_direction:
- case no_direction:
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_RB);
- break;
- case both_direction:
- case write_direction:
- if (abfd->opened_once == true) {
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_RUB);
- if (!abfd->iostream) {
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_WUB);
- }
- } else {
- /*open for creat */
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_WB);
- abfd->opened_once = true;
- }
- break;
- }
+ bfd_boolean ret = TRUE;
- if (abfd->iostream) {
- open_files++;
- bfd_cache_init (abfd);
- }
+ while (bfd_last_cache != NULL)
+ ret &= bfd_cache_close (bfd_last_cache);
- return (FILE *)(abfd->iostream);
+ return ret;
}
/*
INTERNAL_FUNCTION
- bfd_cache_lookup_worker
-
-DESCRIPTION
- Called when the macro <<bfd_cache_lookup>> fails to find a
- quick answer. Finds a file descriptor for this BFD. If
- necessary, it open it. If there are already more than
- BFD_CACHE_MAX_OPEN files open, it trys to close one first, to
- avoid running out of file descriptors.
+ bfd_open_file
SYNOPSIS
- FILE *bfd_cache_lookup_worker(bfd *);
+ 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_cache_lookup_worker,(abfd),
- bfd *abfd)
+bfd_open_file (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 */
- snip (abfd);
- cache_sentinel = insert(abfd, cache_sentinel);
+ 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 = real_fopen (abfd->filename, FOPEN_RB);
+ break;
+ case both_direction:
+ case write_direction:
+ if (abfd->opened_once)
+ {
+ abfd->iostream = real_fopen (abfd->filename, FOPEN_RUB);
+ if (abfd->iostream == NULL)
+ abfd->iostream = real_fopen (abfd->filename, FOPEN_WUB);
}
- }
- /* 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
+ {
+ /* 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 = real_fopen (abfd->filename, FOPEN_WUB);
+ abfd->opened_once = TRUE;
+ }
+ break;
+ }
- BFD_ASSERT(bfd_open_file (abfd) != (FILE *)NULL) ;
- fseek((FILE *)(abfd->iostream), abfd->where, false);
- }
- bfd_last_cache = abfd;
- return (FILE *)(abfd->iostream);
+ if (abfd->iostream == NULL)
+ bfd_set_error (bfd_error_system_call);
+ else
+ {
+ if (! bfd_cache_init (abfd))
+ return NULL;
+ }
+
+ return (FILE *) abfd->iostream;
}
projects / deliverable / binutils-gdb.git / blobdiff