ash,hush: fix SIGCHLD interrupting read builtin

function                                             old     new   delta
readcmd                                              169     217     +48
shell_builtin_read                                  1087    1097     +10
localcmd                                             366     364      -2
builtin_read                                         197     193      -4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/2 up/down: 58/-6)              Total: 52 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/shell/hush.c b/shell/hush.c
index e18920f50..125463a56 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -9038,6 +9038,9 @@ static int FAST_FUNC builtin_type(char **argv)
  * - terminates shell (regardless of interactivity);
  * if it has non-empty trap:
  * - executes trap and returns to read;
+ * SIGCHLD from children:
+ * - does not interrupt read regardless of interactivity:
+ *   try: sleep 1 & read x; echo $x
  */
 static int FAST_FUNC builtin_read(char **argv)
 {
@@ -9071,7 +9074,7 @@ static int FAST_FUNC builtin_read(char **argv)
 
         if ((uintptr_t)r == 1 && errno == EINTR) {
                 unsigned sig = check_and_run_traps();
-                if (sig && sig != SIGINT)
+                if (sig != SIGINT)
                         goto again;
         }