1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_TTY_H 3 #define _LINUX_TTY_H 4 5 #include <linux/fs.h> 6 #include <linux/major.h> 7 #include <linux/termios.h> 8 #include <linux/workqueue.h> 9 #include <linux/tty_buffer.h> 10 #include <linux/tty_driver.h> 11 #include <linux/tty_ldisc.h> 12 #include <linux/tty_port.h> 13 #include <linux/mutex.h> 14 #include <linux/tty_flags.h> 15 #include <uapi/linux/tty.h> 16 #include <linux/rwsem.h> 17 #include <linux/llist.h> 18 #include <linux/android_kabi.h> 19 20 21 /* 22 * (Note: the *_driver.minor_start values 1, 64, 128, 192 are 23 * hardcoded at present.) 24 */ 25 #define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */ 26 #define NR_UNIX98_PTY_RESERVE 1024 /* Default reserve for main devpts */ 27 #define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */ 28 29 /* 30 * This character is the same as _POSIX_VDISABLE: it cannot be used as 31 * a c_cc[] character, but indicates that a particular special character 32 * isn't in use (eg VINTR has no character etc) 33 */ 34 #define __DISABLED_CHAR '\0' 35 36 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR]) 37 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT]) 38 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE]) 39 #define KILL_CHAR(tty) ((tty)->termios.c_cc[VKILL]) 40 #define EOF_CHAR(tty) ((tty)->termios.c_cc[VEOF]) 41 #define TIME_CHAR(tty) ((tty)->termios.c_cc[VTIME]) 42 #define MIN_CHAR(tty) ((tty)->termios.c_cc[VMIN]) 43 #define SWTC_CHAR(tty) ((tty)->termios.c_cc[VSWTC]) 44 #define START_CHAR(tty) ((tty)->termios.c_cc[VSTART]) 45 #define STOP_CHAR(tty) ((tty)->termios.c_cc[VSTOP]) 46 #define SUSP_CHAR(tty) ((tty)->termios.c_cc[VSUSP]) 47 #define EOL_CHAR(tty) ((tty)->termios.c_cc[VEOL]) 48 #define REPRINT_CHAR(tty) ((tty)->termios.c_cc[VREPRINT]) 49 #define DISCARD_CHAR(tty) ((tty)->termios.c_cc[VDISCARD]) 50 #define WERASE_CHAR(tty) ((tty)->termios.c_cc[VWERASE]) 51 #define LNEXT_CHAR(tty) ((tty)->termios.c_cc[VLNEXT]) 52 #define EOL2_CHAR(tty) ((tty)->termios.c_cc[VEOL2]) 53 54 #define _I_FLAG(tty, f) ((tty)->termios.c_iflag & (f)) 55 #define _O_FLAG(tty, f) ((tty)->termios.c_oflag & (f)) 56 #define _C_FLAG(tty, f) ((tty)->termios.c_cflag & (f)) 57 #define _L_FLAG(tty, f) ((tty)->termios.c_lflag & (f)) 58 59 #define I_IGNBRK(tty) _I_FLAG((tty), IGNBRK) 60 #define I_BRKINT(tty) _I_FLAG((tty), BRKINT) 61 #define I_IGNPAR(tty) _I_FLAG((tty), IGNPAR) 62 #define I_PARMRK(tty) _I_FLAG((tty), PARMRK) 63 #define I_INPCK(tty) _I_FLAG((tty), INPCK) 64 #define I_ISTRIP(tty) _I_FLAG((tty), ISTRIP) 65 #define I_INLCR(tty) _I_FLAG((tty), INLCR) 66 #define I_IGNCR(tty) _I_FLAG((tty), IGNCR) 67 #define I_ICRNL(tty) _I_FLAG((tty), ICRNL) 68 #define I_IUCLC(tty) _I_FLAG((tty), IUCLC) 69 #define I_IXON(tty) _I_FLAG((tty), IXON) 70 #define I_IXANY(tty) _I_FLAG((tty), IXANY) 71 #define I_IXOFF(tty) _I_FLAG((tty), IXOFF) 72 #define I_IMAXBEL(tty) _I_FLAG((tty), IMAXBEL) 73 #define I_IUTF8(tty) _I_FLAG((tty), IUTF8) 74 75 #define O_OPOST(tty) _O_FLAG((tty), OPOST) 76 #define O_OLCUC(tty) _O_FLAG((tty), OLCUC) 77 #define O_ONLCR(tty) _O_FLAG((tty), ONLCR) 78 #define O_OCRNL(tty) _O_FLAG((tty), OCRNL) 79 #define O_ONOCR(tty) _O_FLAG((tty), ONOCR) 80 #define O_ONLRET(tty) _O_FLAG((tty), ONLRET) 81 #define O_OFILL(tty) _O_FLAG((tty), OFILL) 82 #define O_OFDEL(tty) _O_FLAG((tty), OFDEL) 83 #define O_NLDLY(tty) _O_FLAG((tty), NLDLY) 84 #define O_CRDLY(tty) _O_FLAG((tty), CRDLY) 85 #define O_TABDLY(tty) _O_FLAG((tty), TABDLY) 86 #define O_BSDLY(tty) _O_FLAG((tty), BSDLY) 87 #define O_VTDLY(tty) _O_FLAG((tty), VTDLY) 88 #define O_FFDLY(tty) _O_FLAG((tty), FFDLY) 89 90 #define C_BAUD(tty) _C_FLAG((tty), CBAUD) 91 #define C_CSIZE(tty) _C_FLAG((tty), CSIZE) 92 #define C_CSTOPB(tty) _C_FLAG((tty), CSTOPB) 93 #define C_CREAD(tty) _C_FLAG((tty), CREAD) 94 #define C_PARENB(tty) _C_FLAG((tty), PARENB) 95 #define C_PARODD(tty) _C_FLAG((tty), PARODD) 96 #define C_HUPCL(tty) _C_FLAG((tty), HUPCL) 97 #define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL) 98 #define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD) 99 #define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS) 100 #define C_CMSPAR(tty) _C_FLAG((tty), CMSPAR) 101 102 #define L_ISIG(tty) _L_FLAG((tty), ISIG) 103 #define L_ICANON(tty) _L_FLAG((tty), ICANON) 104 #define L_XCASE(tty) _L_FLAG((tty), XCASE) 105 #define L_ECHO(tty) _L_FLAG((tty), ECHO) 106 #define L_ECHOE(tty) _L_FLAG((tty), ECHOE) 107 #define L_ECHOK(tty) _L_FLAG((tty), ECHOK) 108 #define L_ECHONL(tty) _L_FLAG((tty), ECHONL) 109 #define L_NOFLSH(tty) _L_FLAG((tty), NOFLSH) 110 #define L_TOSTOP(tty) _L_FLAG((tty), TOSTOP) 111 #define L_ECHOCTL(tty) _L_FLAG((tty), ECHOCTL) 112 #define L_ECHOPRT(tty) _L_FLAG((tty), ECHOPRT) 113 #define L_ECHOKE(tty) _L_FLAG((tty), ECHOKE) 114 #define L_FLUSHO(tty) _L_FLAG((tty), FLUSHO) 115 #define L_PENDIN(tty) _L_FLAG((tty), PENDIN) 116 #define L_IEXTEN(tty) _L_FLAG((tty), IEXTEN) 117 #define L_EXTPROC(tty) _L_FLAG((tty), EXTPROC) 118 119 struct device; 120 struct signal_struct; 121 struct tty_operations; 122 123 /** 124 * struct tty_struct - state associated with a tty while open 125 * 126 * @flow.lock: lock for flow members 127 * @flow.stopped: tty stopped/started by tty_stop/tty_start 128 * @flow.tco_stopped: tty stopped/started by TCOOFF/TCOON ioctls (it has 129 * precedense over @flow.stopped) 130 * @flow.unused: alignment for Alpha, so that no members other than @flow.* are 131 * modified by the same 64b word store. The @flow's __aligned is 132 * there for the very same reason. 133 * @ctrl.lock: lock for ctrl members 134 * @ctrl.pgrp: process group of this tty (setpgrp(2)) 135 * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both 136 * @ctrl.lock and legacy mutex, readers must use at least one of 137 * them. 138 * @ctrl.pktstatus: packet mode status (bitwise OR of TIOCPKT_* constants) 139 * @ctrl.packet: packet mode enabled 140 * 141 * All of the state associated with a tty while the tty is open. Persistent 142 * storage for tty devices is referenced here as @port in struct tty_port. 143 */ 144 struct tty_struct { 145 int magic; 146 struct kref kref; 147 struct device *dev; /* class device or NULL (e.g. ptys, serdev) */ 148 struct tty_driver *driver; 149 const struct tty_operations *ops; 150 int index; 151 152 /* Protects ldisc changes: Lock tty not pty */ 153 struct ld_semaphore ldisc_sem; 154 struct tty_ldisc *ldisc; 155 156 struct mutex atomic_write_lock; 157 struct mutex legacy_mutex; 158 struct mutex throttle_mutex; 159 struct rw_semaphore termios_rwsem; 160 struct mutex winsize_mutex; 161 /* Termios values are protected by the termios rwsem */ 162 struct ktermios termios, termios_locked; 163 char name[64]; 164 unsigned long flags; 165 int count; 166 struct winsize winsize; /* winsize_mutex */ 167 168 struct { 169 spinlock_t lock; 170 bool stopped; 171 bool tco_stopped; 172 unsigned long unused[0]; 173 } __aligned(sizeof(unsigned long)) flow; 174 175 struct { 176 spinlock_t lock; 177 struct pid *pgrp; 178 struct pid *session; 179 unsigned char pktstatus; 180 bool packet; 181 unsigned long unused[0]; 182 } __aligned(sizeof(unsigned long)) ctrl; 183 184 int hw_stopped; 185 unsigned int receive_room; /* Bytes free for queue */ 186 int flow_change; 187 188 struct tty_struct *link; 189 struct fasync_struct *fasync; 190 wait_queue_head_t write_wait; 191 wait_queue_head_t read_wait; 192 struct work_struct hangup_work; 193 void *disc_data; 194 void *driver_data; 195 spinlock_t files_lock; /* protects tty_files list */ 196 struct list_head tty_files; 197 198 #define N_TTY_BUF_SIZE 4096 199 200 int closing; 201 unsigned char *write_buf; 202 int write_cnt; 203 /* If the tty has a pending do_SAK, queue it here - akpm */ 204 struct work_struct SAK_work; 205 struct tty_port *port; 206 207 ANDROID_KABI_RESERVE(1); 208 ANDROID_KABI_RESERVE(2); 209 } __randomize_layout; 210 211 /* Each of a tty's open files has private_data pointing to tty_file_private */ 212 struct tty_file_private { 213 struct tty_struct *tty; 214 struct file *file; 215 struct list_head list; 216 }; 217 218 /* tty magic number */ 219 #define TTY_MAGIC 0x5401 220 221 /* 222 * These bits are used in the flags field of the tty structure. 223 * 224 * So that interrupts won't be able to mess up the queues, 225 * copy_to_cooked must be atomic with respect to itself, as must 226 * tty->write. Thus, you must use the inline functions set_bit() and 227 * clear_bit() to make things atomic. 228 */ 229 #define TTY_THROTTLED 0 /* Call unthrottle() at threshold min */ 230 #define TTY_IO_ERROR 1 /* Cause an I/O error (may be no ldisc too) */ 231 #define TTY_OTHER_CLOSED 2 /* Other side (if any) has closed */ 232 #define TTY_EXCLUSIVE 3 /* Exclusive open mode */ 233 #define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */ 234 #define TTY_LDISC_OPEN 11 /* Line discipline is open */ 235 #define TTY_PTY_LOCK 16 /* pty private */ 236 #define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */ 237 #define TTY_HUPPED 18 /* Post driver->hangup() */ 238 #define TTY_HUPPING 19 /* Hangup in progress */ 239 #define TTY_LDISC_CHANGING 20 /* Change pending - non-block IO */ 240 #define TTY_LDISC_HALTED 22 /* Line discipline is halted */ 241 tty_io_nonblock(struct tty_struct * tty,struct file * file)242 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file) 243 { 244 return file->f_flags & O_NONBLOCK || 245 test_bit(TTY_LDISC_CHANGING, &tty->flags); 246 } 247 tty_io_error(struct tty_struct * tty)248 static inline bool tty_io_error(struct tty_struct *tty) 249 { 250 return test_bit(TTY_IO_ERROR, &tty->flags); 251 } 252 tty_throttled(struct tty_struct * tty)253 static inline bool tty_throttled(struct tty_struct *tty) 254 { 255 return test_bit(TTY_THROTTLED, &tty->flags); 256 } 257 258 #ifdef CONFIG_TTY 259 extern void tty_kref_put(struct tty_struct *tty); 260 extern struct pid *tty_get_pgrp(struct tty_struct *tty); 261 extern void tty_vhangup_self(void); 262 extern void disassociate_ctty(int priv); 263 extern dev_t tty_devnum(struct tty_struct *tty); 264 extern void proc_clear_tty(struct task_struct *p); 265 extern struct tty_struct *get_current_tty(void); 266 /* tty_io.c */ 267 extern int __init tty_init(void); 268 extern const char *tty_name(const struct tty_struct *tty); 269 extern struct tty_struct *tty_kopen_exclusive(dev_t device); 270 extern struct tty_struct *tty_kopen_shared(dev_t device); 271 extern void tty_kclose(struct tty_struct *tty); 272 extern int tty_dev_name_to_number(const char *name, dev_t *number); 273 #else tty_kref_put(struct tty_struct * tty)274 static inline void tty_kref_put(struct tty_struct *tty) 275 { } tty_get_pgrp(struct tty_struct * tty)276 static inline struct pid *tty_get_pgrp(struct tty_struct *tty) 277 { return NULL; } tty_vhangup_self(void)278 static inline void tty_vhangup_self(void) 279 { } disassociate_ctty(int priv)280 static inline void disassociate_ctty(int priv) 281 { } tty_devnum(struct tty_struct * tty)282 static inline dev_t tty_devnum(struct tty_struct *tty) 283 { return 0; } proc_clear_tty(struct task_struct * p)284 static inline void proc_clear_tty(struct task_struct *p) 285 { } get_current_tty(void)286 static inline struct tty_struct *get_current_tty(void) 287 { return NULL; } 288 /* tty_io.c */ tty_init(void)289 static inline int __init tty_init(void) 290 { return 0; } tty_name(const struct tty_struct * tty)291 static inline const char *tty_name(const struct tty_struct *tty) 292 { return "(none)"; } tty_kopen_exclusive(dev_t device)293 static inline struct tty_struct *tty_kopen_exclusive(dev_t device) 294 { return ERR_PTR(-ENODEV); } tty_kclose(struct tty_struct * tty)295 static inline void tty_kclose(struct tty_struct *tty) 296 { } tty_dev_name_to_number(const char * name,dev_t * number)297 static inline int tty_dev_name_to_number(const char *name, dev_t *number) 298 { return -ENOTSUPP; } 299 #endif 300 301 extern struct ktermios tty_std_termios; 302 303 extern int vcs_init(void); 304 305 extern struct class *tty_class; 306 307 /** 308 * tty_kref_get - get a tty reference 309 * @tty: tty device 310 * 311 * Return a new reference to a tty object. The caller must hold 312 * sufficient locks/counts to ensure that their existing reference cannot 313 * go away 314 */ 315 tty_kref_get(struct tty_struct * tty)316 static inline struct tty_struct *tty_kref_get(struct tty_struct *tty) 317 { 318 if (tty) 319 kref_get(&tty->kref); 320 return tty; 321 } 322 323 extern const char *tty_driver_name(const struct tty_struct *tty); 324 extern void tty_wait_until_sent(struct tty_struct *tty, long timeout); 325 extern void stop_tty(struct tty_struct *tty); 326 extern void start_tty(struct tty_struct *tty); 327 extern void tty_write_message(struct tty_struct *tty, char *msg); 328 extern int tty_send_xchar(struct tty_struct *tty, char ch); 329 extern int tty_put_char(struct tty_struct *tty, unsigned char c); 330 extern unsigned int tty_chars_in_buffer(struct tty_struct *tty); 331 extern unsigned int tty_write_room(struct tty_struct *tty); 332 extern void tty_driver_flush_buffer(struct tty_struct *tty); 333 extern void tty_unthrottle(struct tty_struct *tty); 334 extern int tty_throttle_safe(struct tty_struct *tty); 335 extern int tty_unthrottle_safe(struct tty_struct *tty); 336 extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws); 337 extern int tty_get_icount(struct tty_struct *tty, 338 struct serial_icounter_struct *icount); 339 extern int is_current_pgrp_orphaned(void); 340 extern void tty_hangup(struct tty_struct *tty); 341 extern void tty_vhangup(struct tty_struct *tty); 342 extern int tty_hung_up_p(struct file *filp); 343 extern void do_SAK(struct tty_struct *tty); 344 extern void __do_SAK(struct tty_struct *tty); 345 extern void no_tty(void); 346 extern speed_t tty_termios_baud_rate(struct ktermios *termios); 347 extern void tty_termios_encode_baud_rate(struct ktermios *termios, 348 speed_t ibaud, speed_t obaud); 349 extern void tty_encode_baud_rate(struct tty_struct *tty, 350 speed_t ibaud, speed_t obaud); 351 352 /** 353 * tty_get_baud_rate - get tty bit rates 354 * @tty: tty to query 355 * 356 * Returns the baud rate as an integer for this terminal. The 357 * termios lock must be held by the caller and the terminal bit 358 * flags may be updated. 359 * 360 * Locking: none 361 */ tty_get_baud_rate(struct tty_struct * tty)362 static inline speed_t tty_get_baud_rate(struct tty_struct *tty) 363 { 364 return tty_termios_baud_rate(&tty->termios); 365 } 366 367 unsigned char tty_get_char_size(unsigned int cflag); 368 unsigned char tty_get_frame_size(unsigned int cflag); 369 370 extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old); 371 extern int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b); 372 extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt); 373 374 extern void tty_wakeup(struct tty_struct *tty); 375 376 extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file, 377 unsigned int cmd, unsigned long arg); 378 extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg); 379 extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx); 380 extern void tty_release_struct(struct tty_struct *tty, int idx); 381 extern void tty_init_termios(struct tty_struct *tty); 382 extern void tty_save_termios(struct tty_struct *tty); 383 extern int tty_standard_install(struct tty_driver *driver, 384 struct tty_struct *tty); 385 386 extern struct mutex tty_mutex; 387 388 /* n_tty.c */ 389 extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops); 390 #ifdef CONFIG_TTY 391 extern void __init n_tty_init(void); 392 #else n_tty_init(void)393 static inline void n_tty_init(void) { } 394 #endif 395 396 /* tty_audit.c */ 397 #ifdef CONFIG_AUDIT 398 extern void tty_audit_exit(void); 399 extern void tty_audit_fork(struct signal_struct *sig); 400 extern int tty_audit_push(void); 401 #else tty_audit_exit(void)402 static inline void tty_audit_exit(void) 403 { 404 } tty_audit_fork(struct signal_struct * sig)405 static inline void tty_audit_fork(struct signal_struct *sig) 406 { 407 } tty_audit_push(void)408 static inline int tty_audit_push(void) 409 { 410 return 0; 411 } 412 #endif 413 414 /* tty_ioctl.c */ 415 extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file, 416 unsigned int cmd, unsigned long arg); 417 418 /* vt.c */ 419 420 extern int vt_ioctl(struct tty_struct *tty, 421 unsigned int cmd, unsigned long arg); 422 423 extern long vt_compat_ioctl(struct tty_struct *tty, 424 unsigned int cmd, unsigned long arg); 425 426 /* tty_mutex.c */ 427 /* functions for preparation of BKL removal */ 428 extern void tty_lock(struct tty_struct *tty); 429 extern int tty_lock_interruptible(struct tty_struct *tty); 430 extern void tty_unlock(struct tty_struct *tty); 431 extern void tty_lock_slave(struct tty_struct *tty); 432 extern void tty_unlock_slave(struct tty_struct *tty); 433 extern void tty_set_lock_subclass(struct tty_struct *tty); 434 435 #endif 436