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- /* SPDX-License-Identifier: GPL-2.0+ */
- /*
- * termios fuctions to support arbitrary baudrates (on Linux)
- *
- * Copyright (c) 2021 Pali Rohár <pali@kernel.org>
- * Copyright (c) 2021 Marek Behún <marek.behun@nic.cz>
- */
- #ifndef _TERMIOS_LINUX_H_
- #define _TERMIOS_LINUX_H_
- /*
- * We need to use raw TCGETS2/TCSETS2 or TCGETS/TCSETS ioctls with the BOTHER
- * flag in struct termios2/termios, defined in Linux headers <asm/ioctls.h>
- * (included by <sys/ioctl.h>) and <asm/termbits.h>. Since these headers
- * conflict with glibc's header file <termios.h>, it is not possible to use
- * libc's termios functions and we need to reimplement them via ioctl() calls.
- *
- * An arbitrary baudrate is supported when the macro BOTHER is defined. The
- * baudrate value itself is then stored into the c_ospeed and c_ispeed members.
- * If ioctls TCGETS2/TCSETS2 are defined and supported then these fields are
- * present in struct termios2, otherwise these fields are present in struct
- * termios.
- *
- * Note that the Bnnn constants from <termios.h> need not be compatible with Bnnn
- * constants from <asm/termbits.h>.
- */
- #include <errno.h>
- #include <sys/ioctl.h>
- #include <sys/types.h>
- #include <asm/termbits.h>
- #if defined(BOTHER) && defined(TCGETS2)
- #define termios termios2
- #endif
- static inline int tcgetattr(int fd, struct termios *t)
- {
- #if defined(BOTHER) && defined(TCGETS2)
- return ioctl(fd, TCGETS2, t);
- #else
- return ioctl(fd, TCGETS, t);
- #endif
- }
- static inline int tcsetattr(int fd, int a, const struct termios *t)
- {
- int cmd;
- switch (a) {
- #if defined(BOTHER) && defined(TCGETS2)
- case TCSANOW:
- cmd = TCSETS2;
- break;
- case TCSADRAIN:
- cmd = TCSETSW2;
- break;
- case TCSAFLUSH:
- cmd = TCSETSF2;
- break;
- #else
- case TCSANOW:
- cmd = TCSETS;
- break;
- case TCSADRAIN:
- cmd = TCSETSW;
- break;
- case TCSAFLUSH:
- cmd = TCSETSF;
- break;
- #endif
- default:
- errno = EINVAL;
- return -1;
- }
- return ioctl(fd, cmd, t);
- }
- static inline int tcdrain(int fd)
- {
- return ioctl(fd, TCSBRK, 1);
- }
- static inline int tcflush(int fd, int q)
- {
- return ioctl(fd, TCFLSH, q);
- }
- static inline int tcsendbreak(int fd, int d)
- {
- #ifdef TCSBRKP
- return ioctl(fd, TCSBRKP, d);
- #else
- return ioctl(fd, TCSBRK, 0);
- #endif
- }
- static inline int tcflow(int fd, int a)
- {
- return ioctl(fd, TCXONC, a);
- }
- static inline pid_t tcgetsid(int fd)
- {
- pid_t sid;
- if (ioctl(fd, TIOCGSID, &sid) < 0)
- return (pid_t)-1;
- return sid;
- }
- static inline speed_t cfgetospeed(const struct termios *t)
- {
- return t->c_cflag & CBAUD;
- }
- static inline int cfsetospeed(struct termios *t, speed_t s)
- {
- if (s & ~CBAUD) {
- errno = EINVAL;
- return -1;
- }
- t->c_cflag &= ~CBAUD;
- t->c_cflag |= s;
- return 0;
- }
- #ifdef IBSHIFT
- static inline speed_t cfgetispeed(const struct termios *t)
- {
- speed_t s = (t->c_cflag >> IBSHIFT) & CBAUD;
- if (s == B0)
- return cfgetospeed(t);
- else
- return s;
- }
- static inline int cfsetispeed(struct termios *t, speed_t s)
- {
- if (s == 0)
- s = B0;
- if (s & ~CBAUD) {
- errno = EINVAL;
- return -1;
- }
- t->c_cflag &= ~(CBAUD << IBSHIFT);
- t->c_cflag |= s << IBSHIFT;
- return 0;
- }
- #else /* !IBSHIFT */
- static inline speed_t cfgetispeed(const struct termios *t)
- {
- return cfgetospeed(t);
- }
- static inline int cfsetispeed(struct termios *t, speed_t s)
- {
- return cfsetospeed(t, s);
- }
- #endif /* !IBSHIFT */
- static inline int cfsetspeed(struct termios *t, speed_t s)
- {
- if (cfsetospeed(t, s))
- return -1;
- #ifdef IBSHIFT
- if (cfsetispeed(t, s))
- return -1;
- #endif
- return 0;
- }
- static void cfmakeraw(struct termios *t)
- {
- t->c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR |
- ICRNL | IXON);
- t->c_oflag &= ~OPOST;
- t->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
- t->c_cflag &= ~(CSIZE | PARENB);
- t->c_cflag |= CS8;
- }
- #endif /* _TERMIOS_LINUX_H_ */
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