mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-09 23:00:07 +00:00
2cc7bad0ae
C99 specifies that the EOF condition on a file is "sticky": once EOF has been encountered, all subsequent reads should continue to return EOF until the file is closed or something clears the "end-of-file indicator" (e.g. fseek, clearerr). This is arguably a change from C89, where the wording was ambiguous; the BSDs always had sticky EOF, but the System V lineage would attempt to read from the underlying fd again. GNU libc has followed System V for as long as we've been using libio, but nowadays C99 conformance and BSD compatibility are more important than System V compatibility. You might wonder if changing the _underflow impls is sufficient to apply the C99 semantics to all of the many stdio functions that perform input. It should be enough to cover all paths to _IO_SYSREAD, and the only other functions that call _IO_SYSREAD are the _seekoff impls, which is OK because seeking clears EOF, and the _xsgetn impls, which, as far as I can tell, are unused within glibc. The test programs in this patch use a pseudoterminal to set up the necessary conditions. To facilitate this I added a new test-support function that sets up a pair of pty file descriptors for you; it's almost the same as BSD openpty, the only differences are that it allocates the optionally-returned tty pathname with malloc, and that it crashes if anything goes wrong. [BZ #1190] [BZ #19476] * libio/fileops.c (_IO_new_file_underflow): Return EOF immediately if the _IO_EOF_SEEN bit is already set; update commentary. * libio/oldfileops.c (_IO_old_file_underflow): Likewise. * libio/wfileops.c (_IO_wfile_underflow): Likewise. * support/support_openpty.c, support/tty.h: New files. * support/Makefile (libsupport-routines): Add support_openpty. * libio/tst-fgetc-after-eof.c, wcsmbs/test-fgetwc-after-eof.c: New test cases. * libio/Makefile (tests): Add tst-fgetc-after-eof. * wcsmbs/Makefile (tests): Add tst-fgetwc-after-eof.
46 lines
1.8 KiB
C
46 lines
1.8 KiB
C
/* Support functions related to (pseudo)terminals.
|
|
Copyright (C) 2018 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _SUPPORT_TTY_H
|
|
#define _SUPPORT_TTY_H 1
|
|
|
|
struct termios;
|
|
struct winsize;
|
|
|
|
/** Open a pseudoterminal pair. The outer fd is written to the address
|
|
A_OUTER and the inner fd to A_INNER.
|
|
|
|
If A_NAME is not NULL, it will be set to point to a string naming
|
|
the /dev/pts/NNN device corresponding to the inner fd; space for
|
|
this string is allocated with malloc and should be freed by the
|
|
caller when no longer needed. (This is different from the libutil
|
|
function 'openpty'.)
|
|
|
|
If TERMP is not NULL, the terminal parameters will be initialized
|
|
according to the termios structure it points to.
|
|
|
|
If WINP is not NULL, the terminal window size will be set
|
|
accordingly.
|
|
|
|
Terminates the process on failure (like xmalloc). */
|
|
extern void support_openpty (int *a_outer, int *a_inner, char **a_name,
|
|
const struct termios *termp,
|
|
const struct winsize *winp);
|
|
|
|
#endif
|