emacs-27 d424217: Fix 'send-string-to-terminal' writing very long strings

[Eli Zaretskii]

branch: emacs-27
commit d4242177daaee9078245570125c5a99e65f55163
Author: Eli Zaretskii <eliz@gnu.org>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix 'send-string-to-terminal' writing very long strings
    
    * src/dispnew.c (Fsend_string_to_terminal): Prevent partial writes
    by blocking SIGIO while 'fwrite' runs.  (Bug#44320)
---
 src/dispnew.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/dispnew.c b/src/dispnew.c
index 5b6fa51..df55b32 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -5904,8 +5904,12 @@ when TERMINAL is nil.  */)
        }
       out = tty->output;
     }
+  /* STRING might be very long, in which case fwrite could be
+     interrupted by SIGIO.  So we temporarily block SIGIO.  */
+  unrequest_sigio ();
   fwrite (SDATA (string), 1, SBYTES (string), out);
   fflush (out);
+  request_sigio ();
   unblock_input ();
   return Qnil;
 }