From a29ed0e9c9de7c24a3629c01cf943e9e9838bab2 Mon Sep 17 00:00:00 2001 From: schwarze Date: Thu, 25 Aug 2016 19:21:33 +0000 Subject: [PATCH] After read errors, fgetln(3) sometimes succeeded (returning non-NULL) and failed (setting errno and ferror(3)) both at the same time. That's a bad idea in general, and here in particular since returning partial lines was neither reliable (sometimes, you got NULL anyway) nor predictable (almost always, the line would be truncated long before the actual read error). Instead, on read failure, fail properly and always return NULL. Issue found in a discussion with Andrey Chernov who finally agreed to move FreeBSD into the same direction. The fix is joint work with and OK by millert@. --- lib/libc/stdio/fgetln.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/lib/libc/stdio/fgetln.c b/lib/libc/stdio/fgetln.c index ae2eb10f96c..a5ea1b3207e 100644 --- a/lib/libc/stdio/fgetln.c +++ b/lib/libc/stdio/fgetln.c @@ -1,4 +1,4 @@ -/* $OpenBSD: fgetln.c,v 1.14 2015/08/31 02:53:57 guenther Exp $ */ +/* $OpenBSD: fgetln.c,v 1.15 2016/08/25 19:21:33 schwarze Exp $ */ /*- * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. @@ -115,8 +115,11 @@ fgetln(FILE *fp, size_t *lenp) (void)memcpy((void *)(fp->_lb._base + off), (void *)fp->_p, len - off); off = len; - if (__srefill(fp)) - break; /* EOF or error: return partial line */ + if (__srefill(fp)) { + if (fp->_flags & __SEOF) + break; + goto error; + } if ((p = memchr((void *)fp->_p, '\n', fp->_r)) == NULL) continue; -- 2.20.1