Add iterate_over_lwps to gdbserver

This commit introduces a new function, iterate_over_lwps, that
shared Linux code can use to call a function for each LWP that
matches certain criteria.  This function already existed in GDB
and was in use by GDB's various low-level Linux x86 debug register
setters.  An equivalent was written for gdbserver and gdbserver's
low-level Linux x86 debug register setters were modified to use
it.

gdb/ChangeLog:

	* linux-nat.h: Include nat/linux-nat.h.
	(iterate_over_lwps): Move declaration to nat/linux-nat.h.
	* nat/linux-nat.h (struct lwp_info): New forward declaration.
	(iterate_over_lwps_ftype): New typedef.
	(iterate_over_lwps): New declaration.
	* linux-nat.h (iterate_over_lwps): Update comment.  Use
	iterate_over_lwps_ftype.  Update callback return value check.

gdb/gdbserver/ChangeLog:

	* linux-low.h: Include nat/linux-nat.h.
	* linux-low.c (iterate_over_lwps_args): New structure.
	(iterate_over_lwps_filter): New function.
	(iterate_over_lwps): Likewise.
	* linux-x86-low.c (update_debug_registers_callback):
	Update signature to what iterate_over_lwps expects.
	Remove PID check that iterate_over_lwps now performs.
	(x86_dr_low_set_addr): Use iterate_over_lwps.
	(x86_dr_low_set_control): Likewise.

1 files changed, 3 insertions, 6 deletions

diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 8eb73d9..5a2cba5 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -834,14 +834,11 @@ find_lwp_pid (ptid_t ptid)
   return NULL;
 }
 
-/* Call CALLBACK with its second argument set to DATA for every LWP in
-   the list.  If CALLBACK returns 1 for a particular LWP, return a
-   pointer to the structure describing that LWP immediately.
-   Otherwise return NULL.  */
+/* See nat/linux-nat.h.  */
 
 struct lwp_info *
 iterate_over_lwps (ptid_t filter,
-		   int (*callback) (struct lwp_info *, void *),
+		   iterate_over_lwps_ftype callback,
 		   void *data)
 {
   struct lwp_info *lp, *lpnext;
@@ -852,7 +849,7 @@ iterate_over_lwps (ptid_t filter,
 
       if (ptid_match (lp->ptid, filter))
 	{
-	  if ((*callback) (lp, data))
+	  if ((*callback) (lp, data) != 0)
 	    return lp;
 	}
     }