hush: rename last_waitpid_was_0 to we_have_children
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush.c b/shell/hush.c
index fd839d0..7360f0e 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -495,7 +495,7 @@
#if ENABLE_HUSH_FAST
unsigned count_SIGCHLD;
unsigned handled_SIGCHLD;
- smallint last_waitpid_was_0;
+ smallint we_have_children;
#endif
/* which signals have non-DFL handler (even with no traps set)? */
unsigned non_DFL_mask;
@@ -3292,22 +3292,30 @@
debug_printf_jobs("checkjobs %p\n", fg_pipe);
- errno = 0;
-#if ENABLE_HUSH_FAST
- if (G.handled_SIGCHLD == G.count_SIGCHLD) {
-//bb_error_msg("[%d] checkjobs: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d was 0?:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD, G.last_waitpid_was_0);
- /* avoid doing syscall, nothing there anyway */
- if (G.last_waitpid_was_0)
- return 0;
- errno = ECHILD;
- return -1;
- }
-#endif
-
attributes = WUNTRACED;
if (fg_pipe == NULL)
attributes |= WNOHANG;
+ errno = 0;
+#if ENABLE_HUSH_FAST
+ if (G.handled_SIGCHLD == G.count_SIGCHLD) {
+//bb_error_msg("[%d] checkjobs: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d children?:%d fg_pipe:%p",
+//getpid(), G.count_SIGCHLD, G.handled_SIGCHLD, G.we_have_children, fg_pipe);
+ /* There was heither fork nor SIGCHLD since last waitpid */
+ /* Avoid doing syscall, nothing there anyway */
+ if (!G.we_have_children) {
+ errno = ECHILD;
+ return -1;
+ }
+ if (fg_pipe == NULL) { /* is WNOHANG set? */
+ /* We have children, but they did not exit
+ * or stop yet (we saw no SIGCHLD) */
+ return 0;
+ }
+ /* else: !WNOHANG, waitpid will block, can't short-circuit */
+ }
+#endif
+
/* Do we do this right?
* bash-3.00# sleep 20 | false
* <ctrl-Z pressed>
@@ -3330,7 +3338,7 @@
bb_perror_msg("waitpid");
#if ENABLE_HUSH_FAST
else { /* Until next SIGCHLD, waitpid's are useless */
- G.last_waitpid_was_0 = (childpid == 0);
+ G.we_have_children = (childpid == 0);
G.handled_SIGCHLD = i;
//bb_error_msg("[%d] checkjobs: waitpid returned <= 0, G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
}