Check if a signal already has been received before entering a blocking

read as opposed of only doing it afterwards. Issue uncovered by the mail
regress tests.

With claudio@ and ok millert@

diff --git a/usr.bin/mail/tty.c b/usr.bin/mail/tty.c
index 51f7ab7..0cc2bae 100644 (file)
--- a/usr.bin/mail/tty.c
+++ b/usr.bin/mail/tty.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: tty.c,v 1.23 2023/03/08 04:43:11 guenther Exp $       */
+/*     $OpenBSD: tty.c,v 1.24 2023/11/03 19:32:28 anton Exp $  */
 /*     $NetBSD: tty.c,v 1.7 1997/07/09 05:25:46 mikel Exp $    */
 
 /*
@@ -324,7 +324,10 @@ tty_getc(struct tty *t)
        ssize_t         n;
        unsigned char   c;
 
-       n = read(t->fdin, &c, 1);
+       if (ttysignal != 0)
+               n = -1;
+       else
+               n = read(t->fdin, &c, 1);
        switch (n) {
        case -1:
                t->flags |= TTY_ERR;