qemu/util/qemu-openpty.c
AlexChen fae0b0de71 util: Remove redundant checks in the openpty()
As we can see from the following function call stack, amaster and aslave
can not be NULL: char_pty_open() -> qemu_openpty_raw() -> openpty().
In addition, according to the API specification for openpty():
https://www.gnu.org/software/libc/manual/html_node/Pseudo_002dTerminal-Pairs.html,
the arguments name, termp and winp can all be NULL, but arguments amaster or aslave
can not be NULL.
Finally, amaster and aslave has been dereferenced at the beginning of the openpty().
So the checks on amaster and aslave in the openpty() are redundant. Remove them.

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Alex Chen <alex.chen@huawei.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <5F9FE5B8.1030803@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-09-15 14:42:48 +02:00

140 lines
3.8 KiB
C

/*
* qemu-openpty.c
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2010 Red Hat, Inc.
*
* Wrapper function qemu_openpty() implementation.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/*
* This is not part of oslib-posix.c because this function
* uses openpty() which often in -lutil, and if we add this
* dependency to oslib-posix.o, every app will have to be
* linked with -lutil.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#if defined HAVE_PTY_H
# include <pty.h>
#elif defined CONFIG_BSD
# include <termios.h>
# if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
# include <libutil.h>
# else
# include <util.h>
# endif
#elif defined CONFIG_SOLARIS
# include <termios.h>
# include <stropts.h>
#else
# include <termios.h>
#endif
#ifdef __sun__
#if !defined(HAVE_OPENPTY)
/* Once illumos has openpty(), this is going to be removed. */
static int openpty(int *amaster, int *aslave, char *name,
struct termios *termp, struct winsize *winp)
{
const char *slave;
int mfd = -1, sfd = -1;
*amaster = *aslave = -1;
mfd = open("/dev/ptmx", O_RDWR | O_NOCTTY);
if (mfd < 0)
goto err;
if (grantpt(mfd) == -1 || unlockpt(mfd) == -1)
goto err;
if ((slave = ptsname(mfd)) == NULL)
goto err;
if ((sfd = open(slave, O_RDONLY | O_NOCTTY)) == -1)
goto err;
if (ioctl(sfd, I_PUSH, "ptem") == -1 ||
(termp != NULL && tcgetattr(sfd, termp) < 0))
goto err;
*amaster = mfd;
*aslave = sfd;
if (winp)
ioctl(sfd, TIOCSWINSZ, winp);
return 0;
err:
if (sfd != -1)
close(sfd);
close(mfd);
return -1;
}
#endif
static void cfmakeraw (struct termios *termios_p)
{
termios_p->c_iflag &=
~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
termios_p->c_oflag &= ~OPOST;
termios_p->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
termios_p->c_cflag &= ~(CSIZE|PARENB);
termios_p->c_cflag |= CS8;
termios_p->c_cc[VMIN] = 0;
termios_p->c_cc[VTIME] = 0;
}
#endif
int qemu_openpty_raw(int *aslave, char *pty_name)
{
int amaster;
struct termios tty;
#if defined(__OpenBSD__) || defined(__DragonFly__)
char pty_buf[PATH_MAX];
#define q_ptsname(x) pty_buf
#else
char *pty_buf = NULL;
#define q_ptsname(x) ptsname(x)
#endif
if (openpty(&amaster, aslave, pty_buf, NULL, NULL) < 0) {
return -1;
}
/* Set raw attributes on the pty. */
tcgetattr(*aslave, &tty);
cfmakeraw(&tty);
tcsetattr(*aslave, TCSAFLUSH, &tty);
if (pty_name) {
strcpy(pty_name, q_ptsname(amaster));
}
return amaster;
}