diff options
Diffstat (limited to 'drivers/tty/n_tty.cc')
| -rw-r--r-- | drivers/tty/n_tty.cc | 539 |
1 files changed, 0 insertions, 539 deletions
diff --git a/drivers/tty/n_tty.cc b/drivers/tty/n_tty.cc deleted file mode 100644 index 0e312b0..0000000 --- a/drivers/tty/n_tty.cc +++ /dev/null @@ -1,539 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ -/* Copyright (C) 2026 Richard Qin */ - -/* - * n_tty.cc — N_TTY line discipline - * - * Implements the standard terminal line discipline: - * - * Canonical mode (ICANON): - * Input is buffered until newline/EOF. Backspace (VERASE) and - * kill-line (VKILL) editing are supported. - * - * Raw mode (!ICANON): - * Characters are available immediately (subject to VMIN/VTIME). - * - * Signal generation (ISIG): - * VINTR → SIGINT, VQUIT → SIGQUIT, VSUSP → SIGTSTP - * - * Echo (ECHO): - * Typed characters are reflected to output. - * - * Input processing (c_iflag): - * ICRNL: CR → NL mapping - * INLCR: NL → CR mapping - * IGNCR: ignore CR - * ISTRIP: strip high bit - * - * Output processing (c_oflag): - * OPOST + ONLCR: NL → CR+NL on output - * - * Reference: Linux drivers/tty/n_tty.c - */ - -#include <lume/tty.h> -#include <lume/tty_ioctl.h> -#include <lume/signal.h> -#include <lume/signal_nr.h> -#include <lume/slab.h> -#include <lume/new.h> -#include <lume/errno.h> -#include <lume/task.h> -#include <lume/sched.h> - -#ifndef ENOIOCTLCMD -#define ENOIOCTLCMD 515 -#endif - -extern void schedule(); - -/* ================================================================== */ -/* N_TTY internal data */ -/* ================================================================== */ - -inline constexpr int N_TTY_BUF_SIZE = 4096; - -struct n_tty_data { - char read_buf[N_TTY_BUF_SIZE]; - int read_head; /* producer writes here (from receive_buf) */ - int read_tail; /* consumer reads from here (from read()) */ - int canon_head; /* in canonical mode: end of last complete line */ - bool eof_pending; /* Ctrl+D was pressed */ - Spinlock lock; -}; - -static inline int buf_count(const n_tty_data* d) -{ - return (d->read_head - d->read_tail + N_TTY_BUF_SIZE) % N_TTY_BUF_SIZE; -} - -static inline int canon_count(const n_tty_data* d) -{ - return (d->canon_head - d->read_tail + N_TTY_BUF_SIZE) % N_TTY_BUF_SIZE; -} - -static inline bool buf_full(const n_tty_data* d) -{ - return buf_count(d) >= N_TTY_BUF_SIZE - 1; -} - -static inline void buf_put(n_tty_data* d, char c) -{ - d->read_buf[d->read_head] = c; - d->read_head = (d->read_head + 1) % N_TTY_BUF_SIZE; -} - -static inline char buf_get(n_tty_data* d) -{ - char c = d->read_buf[d->read_tail]; - d->read_tail = (d->read_tail + 1) % N_TTY_BUF_SIZE; - return c; -} - -/* ================================================================== */ -/* Output helpers */ -/* ================================================================== */ - -static void tty_put_char(tty_struct* tty, char c) -{ - if (tty->driver && tty->driver->ops && tty->driver->ops->put_char) { - tty->driver->ops->put_char(tty, c); - } -} - -/* - * Process and output a single character, applying c_oflag transformations. - */ -static void tty_output_char(tty_struct* tty, char c) -{ - if (tty->termios_data.c_oflag & OPOST) { - if (c == '\n' && (tty->termios_data.c_oflag & ONLCR)) { - tty_put_char(tty, '\r'); - tty_put_char(tty, '\n'); - return; - } - if (c == '\r' && (tty->termios_data.c_oflag & OCRNL)) { - tty_put_char(tty, '\n'); - return; - } - } - tty_put_char(tty, c); -} - -/* - * Echo a character back to the terminal. - * Control characters are displayed as ^X. - */ -static void echo_char(tty_struct* tty, char c) -{ - if (!(tty->termios_data.c_lflag & ECHO)) - return; - - if (c == '\n') { - tty_output_char(tty, '\n'); - return; - } - - if (c == '\t') { - tty_put_char(tty, '\t'); - return; - } - - /* Control characters: echo as ^X */ - if ((tty->termios_data.c_lflag & ECHOCTL) && c < 0x20 && c != '\t' && c != '\n') { - tty_put_char(tty, '^'); - tty_put_char(tty, c + '@'); - return; - } - - if (c == 0x7f) { /* DEL */ - tty_put_char(tty, '^'); - tty_put_char(tty, '?'); - return; - } - - tty_output_char(tty, c); -} - -/* - * Erase one character visually (backspace + space + backspace). - */ -static void erase_char(tty_struct* tty, char erased) -{ - if (!(tty->termios_data.c_lflag & ECHO)) - return; - - if ((tty->termios_data.c_lflag & ECHOE)) { - /* If the erased char was a control char displayed as ^X, erase 2 cols */ - if ((erased < 0x20 && erased != '\t' && erased != '\n') || erased == 0x7f) { - tty_put_char(tty, '\b'); - tty_put_char(tty, ' '); - tty_put_char(tty, '\b'); - tty_put_char(tty, '\b'); - tty_put_char(tty, ' '); - tty_put_char(tty, '\b'); - } else { - tty_put_char(tty, '\b'); - tty_put_char(tty, ' '); - tty_put_char(tty, '\b'); - } - } -} - -/* ================================================================== */ -/* Input processing — receive_buf (called from IRQ or driver) */ -/* ================================================================== */ - -static void n_tty_receive_buf(tty_struct* tty, const char* cp, int count) -{ - auto* d = static_cast<n_tty_data*>(tty->ldisc.data); - if (!d) return; - - const termios& t = tty->termios_data; - - LockGuard guard(d->lock); - - for (int i = 0; i < count; i++) { - char c = cp[i]; - - /* Strip high bit if requested */ - if (t.c_iflag & ISTRIP) - c &= 0x7f; - - /* Input CR/NL processing */ - if (c == '\r') { - if (t.c_iflag & IGNCR) - continue; - if (t.c_iflag & ICRNL) - c = '\n'; - } else if (c == '\n') { - if (t.c_iflag & INLCR) - c = '\r'; - } - - /* Signal generation */ - if (t.c_lflag & ISIG) { - if (c == t.c_cc[VINTR]) { - tty_signal_pgrp(tty, SIGINT); - echo_char(tty, c); - if (!(t.c_lflag & NOFLSH)) { - /* Flush input buffer */ - d->read_head = d->read_tail; - d->canon_head = d->read_tail; - } - continue; - } - if (c == t.c_cc[VQUIT]) { - tty_signal_pgrp(tty, SIGQUIT); - echo_char(tty, c); - if (!(t.c_lflag & NOFLSH)) { - d->read_head = d->read_tail; - d->canon_head = d->read_tail; - } - continue; - } - if (c == t.c_cc[VSUSP]) { - tty_signal_pgrp(tty, SIGTSTP); - echo_char(tty, c); - continue; - } - } - - /* Canonical mode processing */ - if (t.c_lflag & ICANON) { - /* EOF (Ctrl+D) */ - if (c == t.c_cc[VEOF]) { - d->eof_pending = true; - d->canon_head = d->read_head; - tty->read_wait.wake_all(); - continue; - } - - /* ERASE (backspace/DEL) */ - if (c == t.c_cc[VERASE]) { - if (d->read_head != d->canon_head && - d->read_head != d->read_tail) { - int prev = (d->read_head - 1 + N_TTY_BUF_SIZE) % N_TTY_BUF_SIZE; - char erased = d->read_buf[prev]; - d->read_head = prev; - erase_char(tty, erased); - } - continue; - } - - /* KILL (Ctrl+U — erase entire line) */ - if (c == t.c_cc[VKILL]) { - while (d->read_head != d->canon_head && - d->read_head != d->read_tail) { - int prev = (d->read_head - 1 + N_TTY_BUF_SIZE) % N_TTY_BUF_SIZE; - char erased = d->read_buf[prev]; - d->read_head = prev; - erase_char(tty, erased); - } - if (t.c_lflag & ECHOK) { - tty_output_char(tty, '\n'); - } - continue; - } - - /* WERASE (Ctrl+W — erase word) */ - if ((t.c_lflag & IEXTEN) && c == t.c_cc[VWERASE]) { - /* Skip trailing spaces */ - while (d->read_head != d->canon_head) { - int prev = (d->read_head - 1 + N_TTY_BUF_SIZE) % N_TTY_BUF_SIZE; - if (d->read_buf[prev] != ' ' && d->read_buf[prev] != '\t') - break; - erase_char(tty, d->read_buf[prev]); - d->read_head = prev; - } - /* Erase word */ - while (d->read_head != d->canon_head) { - int prev = (d->read_head - 1 + N_TTY_BUF_SIZE) % N_TTY_BUF_SIZE; - if (d->read_buf[prev] == ' ' || d->read_buf[prev] == '\t') - break; - erase_char(tty, d->read_buf[prev]); - d->read_head = prev; - } - continue; - } - - /* REPRINT (Ctrl+R) */ - if ((t.c_lflag & IEXTEN) && c == t.c_cc[VREPRINT]) { - tty_output_char(tty, '\n'); - int pos = d->canon_head; - while (pos != d->read_head) { - echo_char(tty, d->read_buf[pos]); - pos = (pos + 1) % N_TTY_BUF_SIZE; - } - continue; - } - - /* Regular character — buffer it */ - if (!buf_full(d)) { - buf_put(d, c); - echo_char(tty, c); - } - - /* Line complete on newline or EOL */ - if (c == '\n' || c == t.c_cc[VEOL] || - (t.c_cc[VEOL2] && c == t.c_cc[VEOL2])) { - d->canon_head = d->read_head; - tty->read_wait.wake_all(); - } - } else { - /* Raw / non-canonical mode */ - if (!buf_full(d)) { - buf_put(d, c); - echo_char(tty, c); - tty->read_wait.wake_all(); - } - } - } -} - -/* ================================================================== */ -/* N_TTY read — blocking read from the input buffer */ -/* ================================================================== */ - -static int n_tty_read(tty_struct* tty, file* fp, char* buf, uint64 count) -{ - auto* d = static_cast<n_tty_data*>(tty->ldisc.data); - if (!d) return -EIO; - - const termios& t = tty->termios_data; - TaskControlBlock* curr = current_task(); - int copied = 0; - - if (t.c_lflag & ICANON) { - /* Canonical mode: block until a complete line is available */ - while (canon_count(d) == 0 && !d->eof_pending) { - if (tty->flags & TTY_IO_ERROR) - return -EIO; - - /* Check for pending signals — return -EINTR so the - * trap return path can deliver them via do_signal() */ - if (signal_pending(curr)) - return -EINTR; - - tty->read_wait.prepare_to_wait(curr, TaskState::Sleeping); - if (canon_count(d) == 0 && !d->eof_pending) - schedule(); - tty->read_wait.finish_wait(curr); - } - - if (d->eof_pending && canon_count(d) == 0) { - d->eof_pending = false; - return 0; /* EOF */ - } - - /* Copy up to one line */ - LockGuard guard(d->lock); - while (copied < static_cast<int>(count) && d->read_tail != d->canon_head) { - buf[copied++] = buf_get(d); - } - } else { - /* Non-canonical mode */ - int vmin = t.c_cc[VMIN]; - /* VTIME not implemented (would need timers) */ - - if (vmin == 0) vmin = 1; - - while (buf_count(d) < vmin) { - if (tty->flags & TTY_IO_ERROR) - return -EIO; - - if (signal_pending(curr)) - return -EINTR; - - tty->read_wait.prepare_to_wait(curr, TaskState::Sleeping); - if (buf_count(d) < vmin) - schedule(); - tty->read_wait.finish_wait(curr); - } - - LockGuard guard(d->lock); - while (copied < static_cast<int>(count) && buf_count(d) > 0) { - buf[copied++] = buf_get(d); - } - } - - return copied; -} - -/* ================================================================== */ -/* N_TTY write — output through the driver with post-processing */ -/* ================================================================== */ - -static int n_tty_write(tty_struct* tty, file* fp, const char* buf, uint64 count) -{ - if (!tty->driver || !tty->driver->ops || !tty->driver->ops->write) - return -EIO; - - /* Apply output processing (OPOST) */ - if (tty->termios_data.c_oflag & OPOST) { - for (uint64 i = 0; i < count; i++) { - tty_output_char(tty, buf[i]); - } - return static_cast<int>(count); - } - - /* Raw output: pass directly to driver */ - return tty->driver->ops->write(tty, buf, static_cast<int>(count)); -} - -/* ================================================================== */ -/* N_TTY ioctl */ -/* ================================================================== */ - -static int n_tty_ioctl(tty_struct* tty, unsigned int cmd, uint64 arg) -{ - auto* d = static_cast<n_tty_data*>(tty->ldisc.data); - - switch (cmd) { - case FIONREAD: { - int count = buf_count(d); - auto* p = reinterpret_cast<int*>(arg); - *p = count; - return 0; - } - default: - return -ENOIOCTLCMD; - } -} - -/* ================================================================== */ -/* N_TTY open / close */ -/* ================================================================== */ - -static int n_tty_open(tty_struct* tty) -{ - auto* d = new n_tty_data{}; - if (!d) return -ENOMEM; - - d->read_head = 0; - d->read_tail = 0; - d->canon_head = 0; - d->eof_pending = false; - d->lock.init("n_tty"); - - tty->ldisc.data = d; - return 0; -} - -static void n_tty_close(tty_struct* tty) -{ - auto* d = static_cast<n_tty_data*>(tty->ldisc.data); - if (d) { - delete d; - tty->ldisc.data = nullptr; - } -} - -static void n_tty_flush_buffer(tty_struct* tty) -{ - auto* d = static_cast<n_tty_data*>(tty->ldisc.data); - if (!d) return; - LockGuard guard(d->lock); - d->read_head = 0; - d->read_tail = 0; - d->canon_head = 0; - d->eof_pending = false; -} - -static int n_tty_chars_in_buffer(tty_struct* tty) -{ - auto* d = static_cast<n_tty_data*>(tty->ldisc.data); - if (!d) return 0; - return buf_count(d); -} - -/* - * Probe input readiness for poll(). In canonical mode the read syscall - * blocks until a whole line is queued, so we mirror that: POLLIN only - * when canon_count() shows a finalized line (or pending EOF). In raw - * mode any character satisfies VMIN==1 immediately. Without this - * mirror, ppoll() would falsely signal POLLIN on partial canonical - * input, then read() would block — exactly the busy-loop the shell's - * ppoll-then-read pattern is trying to avoid. - */ -bool n_tty_input_ready(tty_struct* tty) -{ - auto* d = static_cast<n_tty_data*>(tty->ldisc.data); - if (!d) return false; - const termios& t = tty->termios_data; - if (t.c_lflag & ICANON) - return canon_count(d) != 0 || d->eof_pending; - int vmin = t.c_cc[VMIN]; - if (vmin == 0) vmin = 1; - return buf_count(d) >= vmin; -} - -static void n_tty_set_termios(tty_struct* /*tty*/, const termios* /*old*/) -{ - /* Nothing special needed for now */ -} - -static void n_tty_hangup(tty_struct* tty) -{ - n_tty_flush_buffer(tty); - tty->read_wait.wake_all(); -} - -/* ================================================================== */ -/* N_TTY ops table */ -/* ================================================================== */ - -const tty_ldisc_ops n_tty_ops = { - .name = "n_tty", - .num = 0, /* N_TTY */ - .open = n_tty_open, - .close = n_tty_close, - .read = n_tty_read, - .write = n_tty_write, - .receive_buf = n_tty_receive_buf, - .ioctl = n_tty_ioctl, - .flush_buffer = n_tty_flush_buffer, - .chars_in_buffer = n_tty_chars_in_buffer, - .set_termios = n_tty_set_termios, - .hangup = n_tty_hangup, -}; |