From 5efc6af4ebb9d50eb978d0338835544fdfea0396 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 25 Apr 2011 10:40:25 -0400 Subject: [PATCH] fix 2 eof-related bugs in scanf 1. failed match of literal chars from the format string would always return matching failure rather than input failure at eof, leading to infinite loops in some programs. 2. unread of eof would wrongly adjust the character counts reported by %n, yielding an off-by-one error. --- src/stdio/__scanf.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/src/stdio/__scanf.c b/src/stdio/__scanf.c index 185615d3..062327d7 100644 --- a/src/stdio/__scanf.c +++ b/src/stdio/__scanf.c @@ -22,8 +22,7 @@ static int read(rctx_t *r) static void unread(rctx_t *r) { - //if (r->u || r->w < 0) return; - if (r->w < 0) return; + if (r->c < 0 || r->w < 0) return; r->w++; r->u = 1; } @@ -99,7 +98,9 @@ int __scanf(rctx_t *r, const wchar_t *fmt, va_list ap) } else if (*p != '%' || p[1] == '%') { if (*p == '%') p++; r->w = 1; - if (*p++ != read(r)) + if ((c = read(r)) < 0) + goto input_fail; + if (*p++ != c) goto match_fail; continue; } -- 2.25.1