From 1b3f07327ec124b695514a80cb008185e30bcbe0 Mon Sep 17 00:00:00 2001 From: ache Date: Sun, 1 Nov 2015 06:15:14 +0000 Subject: [PATCH] Don't seek to the end if write buffer is empty (in append modes). PR: 204156 MFC after: 1 week --- lib/libc/stdio/ftell.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/lib/libc/stdio/ftell.c b/lib/libc/stdio/ftell.c index abb6da11966c..8cf94ee39c91 100644 --- a/lib/libc/stdio/ftell.c +++ b/lib/libc/stdio/ftell.c @@ -119,7 +119,18 @@ _ftello(FILE *fp, fpos_t *offset) if (HASUB(fp)) pos -= fp->_r; /* Can be negative at this point. */ } else if ((fp->_flags & __SWR) && fp->_p != NULL) { - if ((fp->_flags & __SAPP) || (fp->_flags2 & __S2OAP)) { + /* + * Writing. Any buffered characters cause the + * position to be greater than that in the + * underlying object. + */ + n = fp->_p - fp->_bf._base; + if (pos > OFF_MAX - n) { + errno = EOVERFLOW; + return (1); + } + if (n > 0 && + ((fp->_flags & __SAPP) || (fp->_flags2 & __S2OAP))) { int serrno = errno; errno = 0; @@ -137,16 +148,6 @@ _ftello(FILE *fp, fpos_t *offset) } errno = serrno; } - /* - * Writing. Any buffered characters cause the - * position to be greater than that in the - * underlying object. - */ - n = fp->_p - fp->_bf._base; - if (pos > OFF_MAX - n) { - errno = EOVERFLOW; - return (1); - } pos += n; } *offset = pos; -- 2.39.5