Date: Sat, 16 Aug 2014 01:29:50 +0000 (UTC) From: "Pedro F. Giffuni" <pfg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r270035 - stable/10/lib/libc/stdio Message-ID: <201408160129.s7G1TojV024013@svn.freebsd.org>
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Author: pfg Date: Sat Aug 16 01:29:49 2014 New Revision: 270035 URL: http://svnweb.freebsd.org/changeset/base/270035 Log: MFC r268924: Update fflush(3) to return success on a read-only stream. This is done for compliance with SUSv3. The changes cause no secondary effects in the gnulib tests (we pass them). Obtained from: Apple Inc. (Libc 997.90.3 with changes) Reviewed by: bde Phabric: D440 Modified: stable/10/lib/libc/stdio/fflush.c Directory Properties: stable/10/ (props changed) Modified: stable/10/lib/libc/stdio/fflush.c ============================================================================== --- stable/10/lib/libc/stdio/fflush.c Sat Aug 16 01:06:23 2014 (r270034) +++ stable/10/lib/libc/stdio/fflush.c Sat Aug 16 01:29:49 2014 (r270035) @@ -60,7 +60,7 @@ fflush(FILE *fp) /* * There is disagreement about the correct behaviour of fflush() - * when passed a file which is not open for reading. According to + * when passed a file which is not open for writing. According to * the ISO C standard, the behaviour is undefined. * Under linux, such an fflush returns success and has no effect; * under Windows, such an fflush is documented as behaving instead @@ -68,11 +68,13 @@ fflush(FILE *fp) * Given that applications may be written with the expectation of * either of these two behaviours, the only safe (non-astonishing) * option is to return EBADF and ask that applications be fixed. + * SUSv3 now requires that fflush() returns success on a read-only + * stream. + * */ - if ((fp->_flags & (__SWR | __SRW)) == 0) { - errno = EBADF; - retval = EOF; - } else + if ((fp->_flags & (__SWR | __SRW)) == 0) + retval = 0; + else retval = __sflush(fp); FUNLOCKFILE(fp); return (retval); @@ -89,10 +91,9 @@ __fflush(FILE *fp) if (fp == NULL) return (_fwalk(sflush_locked)); - if ((fp->_flags & (__SWR | __SRW)) == 0) { - errno = EBADF; - retval = EOF; - } else + if ((fp->_flags & (__SWR | __SRW)) == 0) + retval = 0; + else retval = __sflush(fp); return (retval); } @@ -122,6 +123,12 @@ __sflush(FILE *fp) for (; n > 0; n -= t, p += t) { t = _swrite(fp, (char *)p, n); if (t <= 0) { + /* Reset _p and _w. */ + if (p > fp->_p) /* Some was written. */ + memmove(fp->_p, p, n); + fp->_p += n; + if ((fp->_flags & (__SLBF | __SNBF)) == 0) + fp->_w -= n; fp->_flags |= __SERR; return (EOF); }
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