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(unw_is_signal_frame): On Linux, do code-reading to see if a given cursor

is a signal-frame.  This will break if the 8 bytes at EIP are not
	readable.


(Logical change 1.81)
This commit is contained in:
hp.com!davidm 2003-04-21 23:14:14 +00:00
parent 2c7e76f27a
commit c91cfd2f5d

View file

@ -28,6 +28,24 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
int int
unw_is_signal_frame (unw_cursor_t *cursor) unw_is_signal_frame (unw_cursor_t *cursor)
{ {
#ifdef __linux__
struct cursor *c = (struct cursor *) cursor;
unw_accessors_t *a = unw_get_accessors (c->as);
unw_word_t w0, w1;
int ret;
/* Check if EIP points at sigreturn() sequence. On Linux, this is:
0x58 pop %eax
0xb8 0x77 0x00 0x00 0x00 movl 0x77,%eax
0xcd 0x80 int 0x80
*/
if ((ret = (*a->access_mem) (c->as, c->eip, &w0, 0, c->as_arg)) < 0
|| (ret = (*a->access_mem) (c->as, c->eip + 4, &w1, 0, c->as_arg)) < 0)
return ret;
return (w0 == 0x0077b858) && (w1 == 0x80cd0000);
#else
printf ("%s: implement me\n", __FUNCTION__); printf ("%s: implement me\n", __FUNCTION__);
#endif
return -UNW_ENOINFO; return -UNW_ENOINFO;
} }