From c4929eecf7104f266f546ec742ca38ceee0e99c5 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin (Intel)" Date: Wed, 11 Jun 2025 18:35:33 -0700 Subject: [PATCH] io: replace local_isatty() with a proper function __isatty_nostatus() Replace local_isatty() inlined in libio with a proper function __isatty_nostatus(). This allows simpler system-specific implementations that don't need to touch errno at all. Note: I left the prototype in include/unistd.h (the internal header file.) It didn't much make sense to me to put it in a different header (not-cancel.h), but perhaps someone can elucidate the need. Add such an implementation for Linux, with a generic fallback. Signed-off-by: H. Peter Anvin (Intel) Reviewed-by: Adhemerval Zanella --- include/unistd.h | 1 + io/Makefile | 1 + io/isatty_nostatus.c | 29 +++++++++++++++++++++++ libio/filedoalloc.c | 12 +--------- sysdeps/unix/sysv/linux/isatty_nostatus.c | 29 +++++++++++++++++++++++ 5 files changed, 61 insertions(+), 11 deletions(-) create mode 100644 io/isatty_nostatus.c create mode 100644 sysdeps/unix/sysv/linux/isatty_nostatus.c diff --git a/include/unistd.h b/include/unistd.h index e241603b81..376ab5a936 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -152,6 +152,7 @@ libc_hidden_proto (__ttyname_r) extern __pid_t _Fork (void); libc_hidden_proto (_Fork); extern int __isatty (int __fd) attribute_hidden; +extern int __isatty_nostatus (int __fd) attribute_hidden; extern int __link (const char *__from, const char *__to); extern int __symlink (const char *__from, const char *__to); extern int __symlinkat (const char *__from, int __fd, const char *__to); diff --git a/io/Makefile b/io/Makefile index e06f3cb3db..edee38e233 100644 --- a/io/Makefile +++ b/io/Makefile @@ -92,6 +92,7 @@ routines := \ getdirname \ getwd \ isatty \ + isatty_nostatus \ lchmod \ lchown \ link \ diff --git a/io/isatty_nostatus.c b/io/isatty_nostatus.c new file mode 100644 index 0000000000..e8ee796f3b --- /dev/null +++ b/io/isatty_nostatus.c @@ -0,0 +1,29 @@ +/* Copyright (C) 1991-2025 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 + . */ + +#include +#include + +/* Return 1 if FD is a terminal, 0 if not, without changing errno */ +int +__isatty_nostatus (int fd) +{ + int save_errno = errno; + int res = __isatty (fd); + __set_errno (save_errno); + return res; +} diff --git a/libio/filedoalloc.c b/libio/filedoalloc.c index 9ddd75b429..f360d96a9b 100644 --- a/libio/filedoalloc.c +++ b/libio/filedoalloc.c @@ -61,16 +61,6 @@ #include #include -/* Return the result of isatty, without changing errno. */ -static int -local_isatty (int fd) -{ - int save_errno = errno; - int res = __isatty (fd); - __set_errno (save_errno); - return res; -} - /* Allocate a file buffer, or switch to unbuffered I/O. Streams for TTY devices default to line buffered. */ int @@ -90,7 +80,7 @@ _IO_file_doallocate (FILE *fp) #ifdef DEV_TTY_P DEV_TTY_P (&st) || #endif - local_isatty (fp->_fileno)) + __isatty_nostatus (fp->_fileno)) fp->_flags |= _IO_LINE_BUF; } #if defined _STATBUF_ST_BLKSIZE diff --git a/sysdeps/unix/sysv/linux/isatty_nostatus.c b/sysdeps/unix/sysv/linux/isatty_nostatus.c new file mode 100644 index 0000000000..7f110be00c --- /dev/null +++ b/sysdeps/unix/sysv/linux/isatty_nostatus.c @@ -0,0 +1,29 @@ +/* Copyright (C) 1991-2025 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 + . */ + +#include +#include +#include +#include + +/* Return 1 if FD is a terminal, 0 if not, without changing errno */ +int +__isatty_nostatus (int fd) +{ + struct __kernel_termios k_termios; + return INTERNAL_SYSCALL_CALL (ioctl, fd, TCGETS, &k_termios) == 0; +}