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/* Definitions for BFD wrappers used by GDB.
Copyright (C) 2011, 2012
Free Software Foundation, Inc.
This file is part of GDB.
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, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "gdb_bfd.h"
#include "gdb_assert.h"
#include "gdb_string.h"
#include "hashtab.h"
/* See gdb_bfd.h. */
void
gdb_bfd_stash_filename (struct bfd *abfd)
{
char *name = bfd_get_filename (abfd);
char *data;
data = bfd_alloc (abfd, strlen (name) + 1);
strcpy (data, name);
/* Unwarranted chumminess with BFD. */
abfd->filename = data;
}
/* An object of this type is stored in each BFD's user data. */
struct gdb_bfd_data
{
/* The reference count. */
int refc;
/* The mtime of the BFD at the point the cache entry was made. */
time_t mtime;
};
/* A hash table storing all the BFDs maintained in the cache. */
static htab_t gdb_bfd_cache;
/* The type of an object being looked up in gdb_bfd_cache. We use
htab's capability of storing one kind of object (BFD in this case)
and using a different sort of object for searching. */
struct gdb_bfd_cache_search
{
/* The filename. */
const char *filename;
/* The mtime. */
time_t mtime;
};
/* A hash function for BFDs. */
static hashval_t
hash_bfd (const void *b)
{
const bfd *abfd = b;
/* It is simplest to just hash the filename. */
return htab_hash_string (bfd_get_filename (abfd));
}
/* An equality function for BFDs. Note that this expects the caller
to search using struct gdb_bfd_cache_search only, not BFDs. */
static int
eq_bfd (const void *a, const void *b)
{
const bfd *abfd = a;
const struct gdb_bfd_cache_search *s = b;
struct gdb_bfd_data *gdata = bfd_usrdata (abfd);
return (gdata->mtime == s->mtime
&& strcmp (bfd_get_filename (abfd), s->filename) == 0);
}
/* See gdb_bfd.h. */
struct bfd *
gdb_bfd_open (const char *name, const char *target, int fd)
{
hashval_t hash;
void **slot;
bfd *abfd;
struct gdb_bfd_cache_search search;
struct stat st;
if (gdb_bfd_cache == NULL)
gdb_bfd_cache = htab_create_alloc (1, hash_bfd, eq_bfd, NULL,
xcalloc, xfree);
if (fd == -1)
{
fd = open (name, O_RDONLY | O_BINARY);
if (fd == -1)
{
bfd_set_error (bfd_error_system_call);
return NULL;
}
}
search.filename = name;
if (fstat (fd, &st) < 0)
{
/* Weird situation here. */
search.mtime = 0;
}
else
search.mtime = st.st_mtime;
/* Note that this must compute the same result as hash_bfd. */
hash = htab_hash_string (name);
/* Note that we cannot use htab_find_slot_with_hash here, because
opening the BFD may fail; and this would violate hashtab
invariants. */
abfd = htab_find_with_hash (gdb_bfd_cache, &search, hash);
if (abfd != NULL)
{
close (fd);
return gdb_bfd_ref (abfd);
}
abfd = bfd_fopen (name, target, FOPEN_RB, fd);
if (abfd == NULL)
return NULL;
slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash, INSERT);
gdb_assert (!*slot);
*slot = abfd;
gdb_bfd_stash_filename (abfd);
return gdb_bfd_ref (abfd);
}
/* Close ABFD, and warn if that fails. */
static int
gdb_bfd_close_or_warn (struct bfd *abfd)
{
int ret;
char *name = bfd_get_filename (abfd);
ret = bfd_close (abfd);
if (!ret)
warning (_("cannot close \"%s\": %s"),
name, bfd_errmsg (bfd_get_error ()));
return ret;
}
/* Add reference to ABFD. Returns ABFD. */
struct bfd *
gdb_bfd_ref (struct bfd *abfd)
{
struct gdb_bfd_data *gdata;
if (abfd == NULL)
return NULL;
gdata = bfd_usrdata (abfd);
if (gdata != NULL)
{
gdata->refc += 1;
return abfd;
}
gdata = bfd_zalloc (abfd, sizeof (struct gdb_bfd_data));
gdata->refc = 1;
gdata->mtime = bfd_get_mtime (abfd);
bfd_usrdata (abfd) = gdata;
return abfd;
}
/* Unreference and possibly close ABFD. */
void
gdb_bfd_unref (struct bfd *abfd)
{
struct gdb_bfd_data *gdata;
struct gdb_bfd_cache_search search;
if (abfd == NULL)
return;
gdata = bfd_usrdata (abfd);
gdb_assert (gdata->refc >= 1);
gdata->refc -= 1;
if (gdata->refc > 0)
return;
search.filename = bfd_get_filename (abfd);
if (gdb_bfd_cache && search.filename)
{
hashval_t hash = htab_hash_string (search.filename);
void **slot;
search.mtime = gdata->mtime;
slot = htab_find_slot_with_hash (gdb_bfd_cache, &search, hash,
NO_INSERT);
if (slot && *slot)
htab_clear_slot (gdb_bfd_cache, slot);
}
bfd_usrdata (abfd) = NULL; /* Paranoia. */
gdb_bfd_close_or_warn (abfd);
}
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