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authorAlan Modra <amodra@gmail.com>2005-10-27 05:31:16 +0000
committerAlan Modra <amodra@gmail.com>2005-10-27 05:31:16 +0000
commit95560129db4891eb3341c02aedb2087e99176a76 (patch)
treece5177c15a506533e892e3bc63a43a7162c27dc3 /bfd/cache.c
parent182a009999e52ae9e397fa0a628b52027b232e3d (diff)
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PR 973
* cache.c (enum cache_flag): New. (close_one): Save file mtime. (bfd_cache_lookup): Add flag arg, adjust all users. (bfd_cache_lookup_worker): Likewise. (cache_btell): Use CACHE_NO_OPEN and return abfd->where if file not open. (cache_bflush): Similarly, and return success of file not open. (cache_bseek): Use CACHE_NO_SEEK if SEEK_SET or SEEK_END. (cache_bstat): Use CACHE_NO_SEEK_ERROR.
Diffstat (limited to 'bfd/cache.c')
-rw-r--r--bfd/cache.c60
1 files changed, 48 insertions, 12 deletions
diff --git a/bfd/cache.c b/bfd/cache.c
index ca7caa9..ef4a006 100644
--- a/bfd/cache.c
+++ b/bfd/cache.c
@@ -45,6 +45,21 @@ SUBSECTION
#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. */
@@ -150,6 +165,22 @@ close_one (void)
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);
}
@@ -158,10 +189,10 @@ close_one (void)
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) \
+#define bfd_cache_lookup(x, flag) \
((x) == bfd_last_cache \
? (FILE *) (bfd_last_cache->iostream) \
- : bfd_cache_lookup_worker (x))
+ : 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
@@ -171,7 +202,7 @@ close_one (void)
if it is unable to (re)open the @var{abfd}. */
static FILE *
-bfd_cache_lookup_worker (bfd *abfd)
+bfd_cache_lookup_worker (bfd *abfd, enum cache_flag flag)
{
bfd *orig_bfd = abfd;
if ((abfd->flags & BFD_IN_MEMORY) != 0)
@@ -191,9 +222,14 @@ bfd_cache_lookup_worker (bfd *abfd)
return (FILE *) abfd->iostream;
}
+ if (flag & CACHE_NO_OPEN)
+ return NULL;
+
if (bfd_open_file (abfd) == NULL)
;
- else if (real_fseek ((FILE *) abfd->iostream, abfd->where, SEEK_SET) != 0)
+ 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;
@@ -206,16 +242,16 @@ bfd_cache_lookup_worker (bfd *abfd)
static file_ptr
cache_btell (struct bfd *abfd)
{
- FILE *f = bfd_cache_lookup (abfd);
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NO_OPEN);
if (f == NULL)
- return -1;
+ 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);
+ FILE *f = bfd_cache_lookup (abfd, whence != SEEK_CUR ? CACHE_NO_SEEK : 0);
if (f == NULL)
return -1;
return real_fseek (f, offset, whence);
@@ -245,7 +281,7 @@ cache_bread (struct bfd *abfd, void *buf, file_ptr nbytes)
if (nbytes == 0)
return 0;
- f = bfd_cache_lookup (abfd);
+ f = bfd_cache_lookup (abfd, 0);
if (f == NULL)
return 0;
@@ -279,7 +315,7 @@ static file_ptr
cache_bwrite (struct bfd *abfd, const void *where, file_ptr nbytes)
{
file_ptr nwrite;
- FILE *f = bfd_cache_lookup (abfd);
+ FILE *f = bfd_cache_lookup (abfd, 0);
if (f == NULL)
return 0;
nwrite = fwrite (where, 1, nbytes, f);
@@ -301,9 +337,9 @@ static int
cache_bflush (struct bfd *abfd)
{
int sts;
- FILE *f = bfd_cache_lookup (abfd);
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NO_OPEN);
if (f == NULL)
- return -1;
+ return 0;
sts = fflush (f);
if (sts < 0)
bfd_set_error (bfd_error_system_call);
@@ -314,7 +350,7 @@ static int
cache_bstat (struct bfd *abfd, struct stat *sb)
{
int sts;
- FILE *f = bfd_cache_lookup (abfd);
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NO_SEEK_ERROR);
if (f == NULL)
return -1;
sts = fstat (fileno (f), sb);