MFC: r289863,r289931,r290110,r290230,r290231,r290232

r290232:

Microoptimize.

r290231:

Addition to prev. commit.
In some edge cases fp->_p can be changed in _sseek(), recalculate.

r290230:

Don't seek to the end if write buffer is empty (in append modes).
PR:     204156

r290110:

Add _flags2 per jhb@ suggestion since no room left in _flags.
Rewrite O_APPEND flag checking using new __S2OAP flag.

r289931:

According to POSIX, a write operation shall start at the current size of
the stream (if mode had 'a' as the first character).

r289863:

Since no room left in the _flags, reuse __SALC for O_APPEND.
It helps to remove _fcntl() call from _ftello() and optimize seek position
calculation in _swrite().

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/libc/stdio/freopen.c b/lib/libc/stdio/freopen.c
index bf3f030..58227fa 100644
--- a/lib/libc/stdio/freopen.c
+++ b/lib/libc/stdio/freopen.c
@@ -186,6 +186,7 @@ finish:
 	fp->_lb._size = 0;
 	fp->_orientation = 0;
 	memset(&fp->_mbstate, 0, sizeof(mbstate_t));
+	fp->_flags2 = 0;
 
 	if (f < 0) {			/* did not get it after all */
 		if (isopen)
@@ -239,8 +240,10 @@ finish:
 	 * we can do about this.  (We could set __SAPP and check in
 	 * fseek and ftell.)
 	 */
-	if (oflags & O_APPEND)
+	if (oflags & O_APPEND) {
+		fp->_flags2 |= __S2OAP;
 		(void) _sseek(fp, (fpos_t)0, SEEK_END);
+	}
 	FUNLOCKFILE(fp);
 	return (fp);
 }