diff options
Diffstat (limited to 'bfd/cache.c')
| -rw-r--r-- | bfd/cache.c | 60 |
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); |