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, 3 insertions, 1 deletions

diff --git a/lib/libc/stdio/fdopen.c b/lib/libc/stdio/fdopen.c
index 2e19b9f..e5d167a 100644
--- a/lib/libc/stdio/fdopen.c
+++ b/lib/libc/stdio/fdopen.c
@@ -90,7 +90,9 @@ fdopen(int fd, const char *mode)
 	 * O_APPEND bit set, assert __SAPP so that __swrite() caller
 	 * will _sseek() to the end before write.
 	 */
-	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
+	if (fdflags & O_APPEND)
+		fp->_flags2 |= __S2OAP;
+	else if (oflags & O_APPEND)
 		fp->_flags |= __SAPP;
 	fp->_file = fd;
 	fp->_cookie = fp;