/* BFD library -- caching of file descriptors.    Copyright (C) 1990-2026 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 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.  */ /*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 "sysdep.h"#include "bfd.h"#include "libbfd.h"#include "libiberty.h" static FILE *_bfd_open_file_unlocked (bfd *abfd); /* 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 unsigned 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 unsignedbfd_cache_max_open (void){  if (max_open_files == 0)    {      int max;#if defined(__sun) && !defined(__sparcv9) && !defined(__x86_64__)      /* PR ld/19260: 32-bit Solaris has very inelegant handling of the 255	 file descriptor limit.  The problem is that setrlimit(2) can raise	 RLIMIT_NOFILE to a value that is not supported by libc, resulting	 in "Too many open files" errors.  This can happen here even though	 max_open_files is set to rlim.rlim_cur / 8.  For example, if	 a parent process has set rlim.rlim_cur to 65536, then max_open_files	 will be computed as 8192. 	 This check essentially reverts to the behavior from binutils 2.23.1	 for 32-bit Solaris only.  (It is hoped that the 32-bit libc	 limitation will be removed soon).  64-bit Solaris libc does not have	 this limitation.  */      max = 16;#else#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#ifdef _SC_OPEN_MAX	max = sysconf (_SC_OPEN_MAX) / 8;#else	max = 10;#endif#endif /* not 32-bit Solaris */       max_open_files = max < 10 ? 10 : max;    }   return max_open_files;} /* The number of BFD files we have open.  */ static unsigned 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 voidinsert (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 voidsnip (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 boolbfd_cache_delete (bfd *abfd){  bool ret;   if (fclose ((FILE *) abfd->iostream) == 0)    ret = true;  else    {      ret = false;      bfd_set_error (bfd_error_system_call);    }   snip (abfd);   abfd->iostream = NULL;  BFD_ASSERT (open_files > 0);  --open_files;  abfd->flags |= BFD_CLOSED_BY_CACHE;  abfd->last_io = bfd_io_force;   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 boolclose_one (void){  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;	    }	}    }   if (to_kill == NULL)    {      /* There are no open cacheable BFD's.  */      return true;    }   to_kill->where = _bfd_real_ftell ((FILE *) to_kill->iostream);   return bfd_cache_delete (to_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)) /* A helper function that returns true if ABFD can possibly be cached   -- that is, whether bfd_cache_lookup_worker will accept it.  */ static boolpossibly_cached (bfd *abfd){  if ((abfd->flags & BFD_IN_MEMORY) != 0)    return false;  if (abfd->my_archive != NULL      && !bfd_is_thin_archive (abfd->my_archive))    return false;  return true;} /* 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){  if (!possibly_cached (abfd))    abort ();   /* If the BFD is being processed by bfd_check_format_matches, it     must already be open and won't be on the list.  */  if (abfd->in_format_matches)    {      if (abfd->iostream == NULL)	abort ();      return (FILE *) abfd->iostream;    }   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_unlocked (abfd) == NULL)    ;  else if (!(flag & CACHE_NO_SEEK)	   && _bfd_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;   /* xgettext:c-format */  _bfd_error_handler (_("reopening %pB: %s"),		      abfd, bfd_errmsg (bfd_get_error ()));  return NULL;} static file_ptrcache_btell (struct bfd *abfd){  if (!bfd_lock ())    return -1;  FILE *f = bfd_cache_lookup (abfd, CACHE_NO_OPEN);  if (f == NULL)    {      if (!bfd_unlock ())	return -1;      return abfd->where;    }  file_ptr result = _bfd_real_ftell (f);  if (!bfd_unlock ())    return -1;  return result;} static intcache_bseek (struct bfd *abfd, file_ptr offset, int whence){  if (!bfd_lock ())    return -1;  FILE *f = bfd_cache_lookup (abfd, whence != SEEK_CUR ? CACHE_NO_SEEK : CACHE_NORMAL);  if (f == NULL)    {      bfd_unlock ();      return -1;    }  int result = _bfd_real_fseek (f, offset, whence);  if (!bfd_unlock ())    return -1;  return result;} /* 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_ptrcache_bread_1 (FILE *f, void *buf, file_ptr nbytes){  file_ptr nread; #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 nread;    }#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 nread;    }#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;} static file_ptrcache_bread (struct bfd *abfd, void *buf, file_ptr nbytes){  if (!bfd_lock ())    return -1;  file_ptr nread = 0;  FILE *f;   f = bfd_cache_lookup (abfd, CACHE_NORMAL);  if (f == NULL)    {      bfd_unlock ();      return -1;    }   /* 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 (f, (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;    }   if (!bfd_unlock ())    return -1;  return nread;} static file_ptrcache_bwrite (struct bfd *abfd, const void *from, file_ptr nbytes){  if (!bfd_lock ())    return -1;  file_ptr nwrite;  FILE *f = bfd_cache_lookup (abfd, CACHE_NORMAL);   if (f == NULL)    {      if (!bfd_unlock ())	return -1;      return 0;    }  nwrite = fwrite (from, 1, nbytes, f);  if (nwrite < nbytes && ferror (f))    {      bfd_set_error (bfd_error_system_call);      bfd_unlock ();      return -1;    }  if (!bfd_unlock ())    return -1;  return nwrite;} static intcache_bclose (struct bfd *abfd){  /* No locking needed here, it's handled by the callee.  */  return bfd_cache_close (abfd) - 1;} static intcache_bflush (struct bfd *abfd){  if (!bfd_lock ())    return -1;  int sts;  FILE *f = bfd_cache_lookup (abfd, CACHE_NO_OPEN);   if (f == NULL)    {      if (!bfd_unlock ())	return -1;      return 0;    }  sts = fflush (f);  if (sts < 0)    bfd_set_error (bfd_error_system_call);  if (!bfd_unlock ())    return -1;  return sts;} static intcache_bstat (struct bfd *abfd, struct stat *sb){  if (!bfd_lock ())    return -1;  int sts;  FILE *f = bfd_cache_lookup (abfd, CACHE_NO_SEEK_ERROR);   if (f == NULL)    {      bfd_unlock ();      return -1;    }  sts = fstat (fileno (f), sb);  if (sts < 0)    bfd_set_error (bfd_error_system_call);  if (!bfd_unlock ())    return -1;  return sts;} static void *cache_bmmap (struct bfd *abfd ATTRIBUTE_UNUSED,	     void *addr ATTRIBUTE_UNUSED,

Lines 1–500 of 848. Load more