zsh/zsh-serial.patch

 Src/builtin.c |  2 +-
 Src/init.c    | 34 ++++++++++++++++++++++++++++++++--
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/Src/builtin.c b/Src/builtin.c
index 9358e8b..ee14f91 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -5674,7 +5674,7 @@ bin_read(char *name, char **args, Options ops, UNUSED(int func))
 	if (!zleactive) {
 	    if (SHTTY == -1) {
 		/* need to open /dev/tty specially */
-		if ((SHTTY = open("/dev/tty", O_RDWR|O_NOCTTY)) != -1) {
+		if ((SHTTY = block_open("/dev/tty", O_RDWR|O_NOCTTY)) != -1) {
 		    haso = 1;
 		    oshout = shout;
 		    init_shout();
diff --git a/Src/init.c b/Src/init.c
index 102276a..238f6ed 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -545,7 +545,7 @@ init_io(void)
     if (isatty(0)) {
 	zsfree(ttystrname);
 	if ((ttystrname = ztrdup(ttyname(0)))) {
-	    SHTTY = movefd(open(ttystrname, O_RDWR | O_NOCTTY));
+	    SHTTY = movefd(block_open(ttystrname, O_RDWR | O_NOCTTY));
 #ifdef TIOCNXCL
 	    /*
 	     * See if the terminal claims to be busy.  If so, and fd 0
@@ -586,7 +586,7 @@ init_io(void)
 	ttystrname = ztrdup(ttyname(1));
     }
     if (SHTTY == -1 &&
-	(SHTTY = movefd(open("/dev/tty", O_RDWR | O_NOCTTY))) != -1) {
+	(SHTTY = movefd(block_open("/dev/tty", O_RDWR | O_NOCTTY))) != -1) {
 	zsfree(ttystrname);
 	ttystrname = ztrdup(ttyname(SHTTY));
     }
@@ -1713,3 +1713,33 @@ zsh_main(UNUSED(int argc), char **argv)
 		    : "use 'logout' to logout.");
     }
 }
+
+/**/
+int
+block_open (const char *tty, int flags)
+{
+    int saved_errno;
+    int fd;
+
+    if ((flags & O_NONBLOCK) == 0) {
+	fd = open (tty, flags | O_NONBLOCK);
+	if (fd == -1)
+	    return fd;
+	flags = fcntl(fd, F_GETFL);
+	if (flags == -1)
+	    goto bad;
+	flags &= ~O_NONBLOCK;
+	if (fcntl(fd, F_SETFL, flags) == -1)
+	    goto bad;
+    }
+    else
+	fd = open (tty, flags);
+
+    return fd;
+
+bad:
+    saved_errno = errno;
+    close (fd);
+    errno = saved_errno;
+    return -1;
+}