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Diffstat (limited to 'binutils-2.17/bfd/cache.c')
| -rw-r--r-- | binutils-2.17/bfd/cache.c | 532 |
1 files changed, 0 insertions, 532 deletions
diff --git a/binutils-2.17/bfd/cache.c b/binutils-2.17/bfd/cache.c deleted file mode 100644 index 6db6a6b4..00000000 --- a/binutils-2.17/bfd/cache.c +++ /dev/null @@ -1,532 +0,0 @@ -/* BFD library -- caching of file descriptors. - - Copyright 1990, 1991, 1992, 1993, 1994, 1996, 2000, 2001, 2002, - 2003, 2004, 2005 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 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., 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. - -SUBSECTION - Caching functions -*/ - -#include "bfd.h" -#include "sysdep.h" -#include "libbfd.h" -#include "libiberty.h" - -/* 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. */ - -#define BFD_CACHE_MAX_OPEN 10 - -/* The number of BFD files we have open. */ - -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; - -/* 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 -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; - } -} - -/* Close a BFD and remove it from the cache. */ - -static bfd_boolean -bfd_cache_delete (bfd *abfd) -{ - 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; -} - -/* 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) -{ - register bfd *kill; - - 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); - - /* Save the file st_mtime. This is a hack so that gdb can detect when - an executable has been deleted and recreated. The only thing that - makes this reasonable is that st_mtime doesn't change when a file - is unlinked, so saving st_mtime makes BFD's file cache operation - a little more transparent for this particular usage pattern. If we - hadn't closed the file then we would not have lost the original - contents, st_mtime etc. Of course, if something is writing to an - existing file, then this is the wrong thing to do. - FIXME: gdb should save these times itself on first opening a file, - and this hack be removed. */ - if (kill->direction == no_direction || kill->direction == read_direction) - { - bfd_get_mtime (kill); - kill->mtime_set = TRUE; - } - - return bfd_cache_delete (kill); -} - -/* 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) -{ - bfd *orig_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); - 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 file_ptr -cache_btell (struct bfd *abfd) -{ - FILE *f = bfd_cache_lookup (abfd, CACHE_NO_OPEN); - if (f == NULL) - return abfd->where; - return real_ftell (f); -} - -static int -cache_bseek (struct bfd *abfd, file_ptr offset, int whence) -{ - FILE *f = bfd_cache_lookup (abfd, whence != SEEK_CUR ? CACHE_NO_SEEK : 0); - 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 (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, 0); - 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 - 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, 0); - 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); -} - -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 const struct bfd_iovec cache_iovec = { - &cache_bread, &cache_bwrite, &cache_btell, &cache_bseek, - &cache_bclose, &cache_bflush, &cache_bstat -}; - -/* -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) -{ - 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 @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 * -bfd_open_file (bfd *abfd) -{ - 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 = (PTR) real_fopen (abfd->filename, FOPEN_RB); - break; - case both_direction: - case write_direction: - if (abfd->opened_once) - { - abfd->iostream = (PTR) real_fopen (abfd->filename, FOPEN_RUB); - if (abfd->iostream == NULL) - abfd->iostream = (PTR) real_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) real_fopen (abfd->filename, FOPEN_WUB); - abfd->opened_once = TRUE; - } - break; - } - - if (abfd->iostream == NULL) - bfd_set_error (bfd_error_system_call); - else - { - if (! bfd_cache_init (abfd)) - return NULL; - } - - return (FILE *) abfd->iostream; -} |