[src/trunk]: src/lib/libcurses printw: rework vw_printw so it uses open_memst...

[roy <roy%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c6cbcbcc15d3
branches:  trunk
changeset: 840306:c6cbcbcc15d3
user:      roy <roy%NetBSD.org@localhost>
date:      Mon Apr 01 11:39:15 2019 +0000

description:
printw: rework vw_printw so it uses open_memstream rather than funopen2

This makes it more portable as open_memstream is POSIX and fixes a
potential issue with wide characters not fully being printed
due to any buffer overflow.

diffstat:

 lib/libcurses/curses_private.h |   4 +++-
 lib/libcurses/delwin.c         |   5 +++--
 lib/libcurses/newwin.c         |   6 ++++--
 lib/libcurses/printw.c         |  40 +++++++++++++++++-----------------------
 4 files changed, 27 insertions(+), 28 deletions(-)

diffs (142 lines):

diff -r ce732e2b0e83 -r c6cbcbcc15d3 lib/libcurses/curses_private.h
--- a/lib/libcurses/curses_private.h    Mon Apr 01 06:33:57 2019 +0000
+++ b/lib/libcurses/curses_private.h    Mon Apr 01 11:39:15 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: curses_private.h,v 1.68 2018/11/16 10:12:00 blymn Exp $        */
+/*     $NetBSD: curses_private.h,v 1.69 2019/04/01 11:39:15 roy Exp $  */
 
 /*-
  * Copyright (c) 1998-2000 Brett Lymn
@@ -151,6 +151,8 @@
        nschar_t *bnsp;                 /* Background non-spacing char list */
 #endif /* HAVE_WCHAR */
        FILE    *fp;                    /* for window formatted printf */
+       char    *buf;                   /* buffer for window formatted printf */
+       size_t   buflen;                /* length of above buffer */
 };
 
 /* Set of attributes unset by 'me' - 'mb', 'md', 'mh', 'mk', 'mp' and 'mr'. */
diff -r ce732e2b0e83 -r c6cbcbcc15d3 lib/libcurses/delwin.c
--- a/lib/libcurses/delwin.c    Mon Apr 01 06:33:57 2019 +0000
+++ b/lib/libcurses/delwin.c    Mon Apr 01 11:39:15 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: delwin.c,v 1.20 2017/01/06 13:53:18 roy Exp $  */
+/*     $NetBSD: delwin.c,v 1.21 2019/04/01 11:39:15 roy Exp $  */
 
 /*
  * Copyright (c) 1981, 1993, 1994
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "@(#)delwin.c   8.2 (Berkeley) 5/4/94";
 #else
-__RCSID("$NetBSD: delwin.c,v 1.20 2017/01/06 13:53:18 roy Exp $");
+__RCSID("$NetBSD: delwin.c,v 1.21 2019/04/01 11:39:15 roy Exp $");
 #endif
 #endif                         /* not lint */
 
@@ -114,6 +114,7 @@
                _cursesi_screen->__virtscr = NULL;
        if (win->fp)
                fclose(win->fp);
+       free(win->buf);
        free(win);
        return OK;
 }
diff -r ce732e2b0e83 -r c6cbcbcc15d3 lib/libcurses/newwin.c
--- a/lib/libcurses/newwin.c    Mon Apr 01 06:33:57 2019 +0000
+++ b/lib/libcurses/newwin.c    Mon Apr 01 11:39:15 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: newwin.c,v 1.54 2018/10/10 09:40:11 roy Exp $  */
+/*     $NetBSD: newwin.c,v 1.55 2019/04/01 11:39:15 roy Exp $  */
 
 /*
  * Copyright (c) 1981, 1993, 1994
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "@(#)newwin.c   8.3 (Berkeley) 7/27/94";
 #else
-__RCSID("$NetBSD: newwin.c,v 1.54 2018/10/10 09:40:11 roy Exp $");
+__RCSID("$NetBSD: newwin.c,v 1.55 2019/04/01 11:39:15 roy Exp $");
 #endif
 #endif                         /* not lint */
 
@@ -303,6 +303,8 @@
        __CTRACE(__CTRACE_WINDOW, "makenew: win = %p\n", win);
 #endif
        win->fp = NULL;
+       win->buf = NULL;
+       win->buflen = 0;
 
        /* Set up line pointer array and line space. */
        if ((win->alines = malloc(nlines * sizeof(__LINE *))) == NULL) {
diff -r ce732e2b0e83 -r c6cbcbcc15d3 lib/libcurses/printw.c
--- a/lib/libcurses/printw.c    Mon Apr 01 06:33:57 2019 +0000
+++ b/lib/libcurses/printw.c    Mon Apr 01 11:39:15 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: printw.c,v 1.26 2019/03/28 23:24:22 uwe Exp $  */
+/*     $NetBSD: printw.c,v 1.27 2019/04/01 11:39:15 roy Exp $  */
 
 /*
  * Copyright (c) 1981, 1993, 1994
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "@(#)printw.c   8.3 (Berkeley) 5/4/94";
 #else
-__RCSID("$NetBSD: printw.c,v 1.26 2019/03/28 23:24:22 uwe Exp $");
+__RCSID("$NetBSD: printw.c,v 1.27 2019/04/01 11:39:15 roy Exp $");
 #endif
 #endif                         /* not lint */
 
@@ -110,22 +110,7 @@
        va_end(ap);
        return ret;
 }
-/*
- * Internal write-buffer-to-window function.
- */
-static ssize_t
-winwrite(void *cookie, const void *vbuf, size_t n)
-{
-       WINDOW *win = cookie;
-       const char *buf = vbuf;
-       int status;
 
-       status = waddnstr(win, buf, n);
-       if (status == ERR)
-           return -1;
-
-       return (ssize_t)n;
-}
 /*
  * vw_printw --
  *     This routine actually executes the printf and adds it to the window.
@@ -133,14 +118,23 @@
 int
 vw_printw(WINDOW *win, const char *fmt, va_list ap)
 {
+       int n;
+
        if (win->fp == NULL) {
-               win->fp = funopen2(win, NULL, winwrite, NULL, NULL, NULL);
-               if (win->fp == NULL)
+               win->fp = open_memstream(&win->buf, &win->buflen);
+               if (__predict_false(win->fp == NULL))
                        return ERR;
-       }
-       vfprintf(win->fp, fmt, ap);
-       fflush(win->fp);
-       return OK;
+       } else
+               rewind(win->fp);
+
+       n = vfprintf(win->fp, fmt, ap);
+       if (__predict_false(n == 0))
+               return OK;
+       if (__predict_false(n == -1))
+               return ERR;
+       if (__predict_false(fflush(win->fp) != 0))
+               return ERR;
+       return waddnstr(win, win->buf, n);
 }
 
 __strong_alias(vwprintw, vw_printw)