PROTECTED void
unw_map_local_cursor_get (unw_map_cursor_t *map_cursor)
{
intrmask_t saved_mask;
lock_rdwr_wr_acquire (&local_rdwr_lock, saved_mask);
map_cursor->map_list = local_map_list;
map_cursor->cur_map = local_map_list;
lock_rdwr_release (&local_rdwr_lock, saved_mask);
}
PROTECTED void
unw_map_local_destroy (void)
{
intrmask_t saved_mask;
lock_rdwr_wr_acquire (&local_rdwr_lock, saved_mask);
if (local_map_list != NULL && --local_map_list_refs == 0)
{
map_destroy_list (local_map_list);
local_map_list = NULL;
}
lock_rdwr_release (&local_rdwr_lock, saved_mask);
}
PROTECTED int
unw_map_local_create (void)
{
intrmask_t saved_mask;
int ret_value = 0;
lock_rdwr_wr_acquire (&local_rdwr_lock, saved_mask);
if (local_map_list_refs == 0)
{
local_map_list = map_create_list (getpid());
if (local_map_list != NULL)
local_map_list_refs = 1;
else
ret_value = -1;
}
else
local_map_list_refs++;
lock_rdwr_release (&local_rdwr_lock, saved_mask);
return ret_value;
}
/* In order to cache as much as possible while unwinding the local process,
we gather a map of the process before starting. If the cache is missing
a map, or a map exists but doesn't have the "expected_flags" set, then
check if the cache needs to be regenerated.
While regenerating the list, grab a write lock to avoid any readers using
the list while it's being modified. */
static int
rebuild_if_necessary (unw_word_t addr, int expected_flags, size_t bytes)
{
struct map_info *map;
struct map_info *new_list;
int ret_value = -1;
intrmask_t saved_mask;
new_list = map_create_list (UNW_MAP_CREATE_LOCAL, getpid());
map = map_find_from_addr (new_list, addr);
if (map && (map->end - addr >= bytes) && (expected_flags == 0 || (map->flags & expected_flags)))
{
/* Get a write lock on local_map_list since it's going to be modified. */
lock_rdwr_wr_acquire (&local_rdwr_lock, saved_mask);
/* Just in case another thread rebuilt the map, check to see if the
ip with expected_flags is in local_map_list. If not, the assumption
is that new_list is newer than local_map_list because the map only
gets new maps with new permissions. If this is not true, then it
would be necessary to regenerate the list one more time. */
ret_value = 0;
map = map_find_from_addr (local_map_list, addr);
if (!map || (map->end - addr < bytes) || (expected_flags != 0 && !(map->flags & expected_flags)))
{
/* Move any cached items to the new list. */
move_cached_elf_data (local_map_list, new_list);
map = local_map_list;
local_map_list = new_list;
new_list = map;
}
lock_rdwr_release (&local_rdwr_lock, saved_mask);
}
map_destroy_list (new_list);
return ret_value;
}
