static int
is_flag_set (unw_word_t addr, int flag, size_t bytes)
{
struct map_info *map;
int ret = 0;
intrmask_t saved_mask;
lock_rdwr_rd_acquire (&local_rdwr_lock, saved_mask);
map = map_find_from_addr (local_map_list, addr);
if (map != NULL)
{
if (map->flags & MAP_FLAGS_DEVICE_MEM)
{
lock_rdwr_release (&local_rdwr_lock, saved_mask);
return 0;
}
/* Do not bother checking if the next map is readable and right at
* the end of this map. All of the reads/writes are of small values
* that should never span a map.
*/
if (map->end - addr < bytes)
ret = 0;
else
ret = map->flags & flag;
}
lock_rdwr_release (&local_rdwr_lock, saved_mask);
if (!ret && rebuild_if_necessary (addr, flag, bytes) == 0)
{
return 1;
}
return ret;
}
PROTECTED int
local_get_elf_image (unw_addr_space_t as, struct elf_image *ei, unw_word_t ip,
unsigned long *segbase, unsigned long *mapoff, char **path, void *as_arg)
{
struct map_info *map;
intrmask_t saved_mask;
int return_value = -UNW_ENOINFO;
lock_rdwr_rd_acquire (&local_rdwr_lock, saved_mask);
map = map_find_from_addr (local_map_list, ip);
if (!map)
{
lock_rdwr_release (&local_rdwr_lock, saved_mask);
if (rebuild_if_necessary (ip, 0, sizeof(unw_word_t)) < 0)
return -UNW_ENOINFO;
lock_rdwr_rd_acquire (&local_rdwr_lock, saved_mask);
map = map_find_from_addr (local_map_list, ip);
}
if (map && elf_map_cached_image (as, as_arg, map, ip, true))
{
/* It is absolutely necessary that the elf structure is a copy of
* the map data. The map could be rebuilt and the old ei pointer
* will be modified and thrown away.
*/
*ei = map->ei;
*segbase = map->start;
if (ei->mapped)
*mapoff = map->offset;
else
/* Always use zero as the map offset for in memory maps. The
* dlopen of a shared library from an APK will result in a
* non-zero offset so it won't match the elf data and cause
* unwinds to fail. Currently, only in memory unwinds of an APK
* are possible, so only modify this path.
*/
*mapoff = 0;
if (path != NULL)
{
if (map->path)
*path = strdup(map->path);
else
*path = NULL;
}
return_value = 0;
}
lock_rdwr_release (&local_rdwr_lock, saved_mask);
return return_value;
}
PROTECTED int
unw_map_local_cursor_get_next (unw_map_cursor_t *map_cursor, unw_map_t *unw_map)
{
struct map_info *map_info = map_cursor->cur_map;
intrmask_t saved_mask;
int ret = 1;
if (map_info == NULL)
return 0;
lock_rdwr_rd_acquire (&local_rdwr_lock, saved_mask);
if (map_cursor->map_list != local_map_list)
{
map_cursor->map_list = local_map_list;
ret = -UNW_EINVAL;
}
else
{
unw_map->start = map_info->start;
unw_map->end = map_info->end;
unw_map->flags = map_info->flags;
if (map_info->path)
unw_map->path = strdup (map_info->path);
else
unw_map->path = NULL;
map_cursor->cur_map = map_info->next;
}
lock_rdwr_release (&local_rdwr_lock, saved_mask);
return ret;
}
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 char *
map_local_get_image_name (unw_word_t ip)
{
struct map_info *map;
intrmask_t saved_mask;
char *image_name = NULL;
lock_rdwr_rd_acquire (&local_rdwr_lock, saved_mask);
map = map_find_from_addr (local_map_list, ip);
if (!map)
{
lock_rdwr_release (&local_rdwr_lock, saved_mask);
if (rebuild_if_necessary (ip, 0, sizeof(unw_word_t)) < 0)
return NULL;
lock_rdwr_rd_acquire (&local_rdwr_lock, saved_mask);
map = map_find_from_addr (local_map_list, ip);
}
if (map)
image_name = strdup (map->path);
lock_rdwr_release (&local_rdwr_lock, saved_mask);
return image_name;
}
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;
}
