diff options
Diffstat (limited to 'drivers/char/n_tty.c')
| -rw-r--r-- | drivers/char/n_tty.c | 792 |
1 files changed, 620 insertions, 172 deletions
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c index efbfe9612658..f6f0e4ec2b51 100644 --- a/drivers/char/n_tty.c +++ b/drivers/char/n_tty.c @@ -47,8 +47,8 @@ #include <linux/bitops.h> #include <linux/audit.h> #include <linux/file.h> +#include <linux/uaccess.h> -#include <asm/uaccess.h> #include <asm/system.h> /* number of characters left in xmit buffer before select has we have room */ @@ -62,6 +62,17 @@ #define TTY_THRESHOLD_THROTTLE 128 /* now based on remaining room */ #define TTY_THRESHOLD_UNTHROTTLE 128 +/* + * Special byte codes used in the echo buffer to represent operations + * or special handling of characters. Bytes in the echo buffer that + * are not part of such special blocks are treated as normal character + * codes. + */ +#define ECHO_OP_START 0xff +#define ECHO_OP_MOVE_BACK_COL 0x80 +#define ECHO_OP_SET_CANON_COL 0x81 +#define ECHO_OP_ERASE_TAB 0x82 + static inline unsigned char *alloc_buf(void) { gfp_t prio = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL; @@ -169,6 +180,7 @@ static void check_unthrottle(struct tty_struct *tty) * * Locking: tty_read_lock for read fields. */ + static void reset_buffer_flags(struct tty_struct *tty) { unsigned long flags; @@ -176,6 +188,11 @@ static void reset_buffer_flags(struct tty_struct *tty) spin_lock_irqsave(&tty->read_lock, flags); tty->read_head = tty->read_tail = tty->read_cnt = 0; spin_unlock_irqrestore(&tty->read_lock, flags); + + mutex_lock(&tty->echo_lock); + tty->echo_pos = tty->echo_cnt = tty->echo_overrun = 0; + mutex_unlock(&tty->echo_lock); + tty->canon_head = tty->canon_data = tty->erasing = 0; memset(&tty->read_flags, 0, sizeof tty->read_flags); n_tty_set_room(tty); @@ -266,89 +283,118 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty) } /** - * opost - output post processor + * do_output_char - output one character * @c: character (or partial unicode symbol) * @tty: terminal device + * @space: space available in tty driver write buffer * - * Perform OPOST processing. Returns -1 when the output device is - * full and the character must be retried. Note that Linux currently - * ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY. They simply aren't - * relevant in the world today. If you ever need them, add them here. + * This is a helper function that handles one output character + * (including special characters like TAB, CR, LF, etc.), + * putting the results in the tty driver's write buffer. + * + * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY + * and NLDLY. They simply aren't relevant in the world today. + * If you ever need them, add them here. + * + * Returns the number of bytes of buffer space used or -1 if + * no space left. * - * Called from both the receive and transmit sides and can be called - * re-entrantly. Relies on lock_kernel() for tty->column state. + * Locking: should be called under the output_lock to protect + * the column state and space left in the buffer */ -static int opost(unsigned char c, struct tty_struct *tty) +static int do_output_char(unsigned char c, struct tty_struct *tty, int space) { - int space, spaces; + int spaces; - space = tty_write_room(tty); if (!space) return -1; - lock_kernel(); - if (O_OPOST(tty)) { - switch (c) { - case '\n': - if (O_ONLRET(tty)) - tty->column = 0; - if (O_ONLCR(tty)) { - if (space < 2) { - unlock_kernel(); - return -1; - } - tty_put_char(tty, '\r'); - tty->column = 0; - } - tty->canon_column = tty->column; - break; - case '\r': - if (O_ONOCR(tty) && tty->column == 0) { - unlock_kernel(); - return 0; - } - if (O_OCRNL(tty)) { - c = '\n'; - if (O_ONLRET(tty)) - tty->canon_column = tty->column = 0; - break; - } + switch (c) { + case '\n': + if (O_ONLRET(tty)) + tty->column = 0; + if (O_ONLCR(tty)) { + if (space < 2) + return -1; tty->canon_column = tty->column = 0; + tty_put_char(tty, '\r'); + tty_put_char(tty, c); + return 2; + } + tty->canon_column = tty->column; + break; + case '\r': + if (O_ONOCR(tty) && tty->column == 0) + return 0; + if (O_OCRNL(tty)) { + c = '\n'; + if (O_ONLRET(tty)) + tty->canon_column = tty->column = 0; break; - case '\t': - spaces = 8 - (tty->column & 7); - if (O_TABDLY(tty) == XTABS) { - if (space < spaces) { - unlock_kernel(); - return -1; - } - tty->column += spaces; - tty->ops->write(tty, " ", spaces); - unlock_kernel(); - return 0; - } + } + tty->canon_column = tty->column = 0; + break; + case '\t': + spaces = 8 - (tty->column & 7); + if (O_TABDLY(tty) == XTABS) { + if (space < spaces) + return -1; tty->column += spaces; - break; - case '\b': - if (tty->column > 0) - tty->column--; - break; - default: + tty->ops->write(tty, " ", spaces); + return spaces; + } + tty->column += spaces; + break; + case '\b': + if (tty->column > 0) + tty->column--; + break; + default: + if (!iscntrl(c)) { if (O_OLCUC(tty)) c = toupper(c); - if (!iscntrl(c) && !is_continuation(c, tty)) + if (!is_continuation(c, tty)) tty->column++; - break; } + break; } + tty_put_char(tty, c); - unlock_kernel(); - return 0; + return 1; } /** - * opost_block - block postprocess + * process_output - output post processor + * @c: character (or partial unicode symbol) + * @tty: terminal device + * + * Perform OPOST processing. Returns -1 when the output device is + * full and the character must be retried. + * + * Locking: output_lock to protect column state and space left + * (also, this is called from n_tty_write under the + * tty layer write lock) + */ + +static int process_output(unsigned char c, struct tty_struct *tty) +{ + int space, retval; + + mutex_lock(&tty->output_lock); + + space = tty_write_room(tty); + retval = do_output_char(c, tty, space); + + mutex_unlock(&tty->output_lock); + if (retval < 0) + return -1; + else + return 0; +} + +/** + * process_output_block - block post processor * @tty: terminal device * @inbuf: user buffer * @nr: number of bytes @@ -358,26 +404,32 @@ static int opost(unsigned char c, struct tty_struct *tty) * the simple cases normally found and helps to generate blocks of * symbols for the console driver and thus improve performance. * - * Called from n_tty_write under the tty layer write lock. Relies - * on lock_kernel for the tty->column state. + * Locking: output_lock to protect column state and space left + * (also, this is called from n_tty_write under the + * tty layer write lock) */ -static ssize_t opost_block(struct tty_struct *tty, - const unsigned char *buf, unsigned int nr) +static ssize_t process_output_block(struct tty_struct *tty, + const unsigned char *buf, unsigned int nr) { int space; int i; const unsigned char *cp; + mutex_lock(&tty->output_lock); + space = tty_write_room(tty); - if (!space) + if (!space) { + mutex_unlock(&tty->output_lock); return 0; + } if (nr > space) nr = space; - lock_kernel(); for (i = 0, cp = buf; i < nr; i++, cp++) { - switch (*cp) { + unsigned char c = *cp; + + switch (c) { case '\n': if (O_ONLRET(tty)) tty->column = 0; @@ -399,54 +451,403 @@ static ssize_t opost_block(struct tty_struct *tty, tty->column--; break; default: - if (O_OLCUC(tty)) - goto break_out; - if (!iscntrl(*cp)) - tty->column++; + if (!iscntrl(c)) { + if (O_OLCUC(tty)) + goto break_out; + if (!is_continuation(c, tty)) + tty->column++; + } break; } } break_out: - if (tty->ops->flush_chars) - tty->ops->flush_chars(tty); i = tty->ops->write(tty, buf, i); - unlock_kernel(); + + mutex_unlock(&tty->output_lock); return i; } +/** + * process_echoes - write pending echo characters + * @tty: terminal device + * + * Write previously buffered echo (and other ldisc-generated) + * characters to the tty. + * + * Characters generated by the ldisc (including echoes) need to + * be buffered because the driver's write buffer can fill during + * heavy program output. Echoing straight to the driver will + * often fail under these conditions, causing lost characters and + * resulting mismatches of ldisc state information. + * + * Since the ldisc state must represent the characters actually sent + * to the driver at the time of the write, operations like certain + * changes in column state are also saved in the buffer and executed + * here. + * + * A circular fifo buffer is used so that the most recent characters + * are prioritized. Also, when control characters are echoed with a + * prefixed "^", the pair is treated atomically and thus not separated. + * + * Locking: output_lock to protect column state and space left, + * echo_lock to protect the echo buffer + */ + +static void process_echoes(struct tty_struct *tty) +{ + int space, nr; + unsigned char c; + unsigned char *cp, *buf_end; + + if (!tty->echo_cnt) + return; + + mutex_lock(&tty->output_lock); + mutex_lock(&tty->echo_lock); + + space = tty_write_room(tty); + + buf_end = tty->echo_buf + N_TTY_BUF_SIZE; + cp = tty->echo_buf + tty->echo_pos; + nr = tty->echo_cnt; + while (nr > 0) { + c = *cp; + if (c == ECHO_OP_START) { + unsigned char op; + unsigned char *opp; + int no_space_left = 0; + + /* + * If the buffer byte is the start of a multi-byte + * operation, get the next byte, which is either the + * op code or a control character value. + */ + opp = cp + 1; + if (opp == buf_end) + opp -= N_TTY_BUF_SIZE; + op = *opp; + + switch (op) { + unsigned int num_chars, num_bs; + + case ECHO_OP_ERASE_TAB: + if (++opp == buf_end) + opp -= N_TTY_BUF_SIZE; + num_chars = *opp; + + /* + * Determine how many columns to go back + * in order to erase the tab. + * This depends on the number of columns + * used by other characters within the tab + * area. If this (modulo 8) count is from + * the start of input rather than from a + * previous tab, we offset by canon column. + * Otherwise, tab spacing is normal. + */ + if (!(num_chars & 0x80)) + num_chars += tty->canon_column; + num_bs = 8 - (num_chars & 7); + + if (num_bs > space) { + no_space_left = 1; + break; + } + space -= num_bs; + while (num_bs--) { + tty_put_char(tty, '\b'); + if (tty->column > 0) + tty->column--; + } + cp += 3; + nr -= 3; + break; + + case ECHO_OP_SET_CANON_COL: + tty->canon_column = tty->column; + cp += 2; + nr -= 2; + break; + + case ECHO_OP_MOVE_BACK_COL: + if (tty->column > 0) + tty->column--; + cp += 2; + nr -= 2; + break; + + case ECHO_OP_START: + /* This is an escaped echo op start code */ + if (!space) { + no_space_left = 1; + break; + } + tty_put_char(tty, ECHO_OP_START); + tty->column++; + space--; + cp += 2; + nr -= 2; + break; + + default: + if (iscntrl(op)) { + if (L_ECHOCTL(tty)) { + /* + * Ensure there is enough space + * for the whole ctrl pair. + */ + if (space < 2) { + no_space_left = 1; + break; + } + tty_put_char(tty, '^'); + tty_put_char(tty, op ^ 0100); + tty->column += 2; + space -= 2; + } else { + if (!space) { + no_space_left = 1; + break; + } + tty_put_char(tty, op); + space--; + } + } + /* + * If above falls through, this was an + * undefined op. + */ + cp += 2; + nr -= 2; + } + + if (no_space_left) + break; + } else { + int retval; + + retval = do_output_char(c, tty, space); + if (retval < 0) + break; + space -= retval; + cp += 1; + nr -= 1; + } + + /* When end of circular buffer reached, wrap around */ + if (cp >= buf_end) + cp -= N_TTY_BUF_SIZE; + } + + if (nr == 0) { + tty->echo_pos = 0; + tty->echo_cnt = 0; + tty->echo_overrun = 0; + } else { + int num_processed = tty->echo_cnt - nr; + tty->echo_pos += num_processed; + tty->echo_pos &= N_TTY_BUF_SIZE - 1; + tty->echo_cnt = nr; + if (num_processed > 0) + tty->echo_overrun = 0; + } + + mutex_unlock(&tty->echo_lock); + mutex_unlock(&tty->output_lock); + + if (tty->ops->flush_chars) + tty->ops->flush_chars(tty); +} /** - * echo_char - echo characters + * add_echo_byte - add a byte to the echo buffer + * @c: unicode byte to echo + * @tty: terminal device + * + * Add a character or operation byte to the echo buffer. + * + * Should be called under the echo lock to protect the echo buffer. + */ + +static void add_echo_byte(unsigned char c, struct tty_struct *tty) +{ + int new_byte_pos; + + if (tty->echo_cnt == N_TTY_BUF_SIZE) { + /* Circular buffer is already at capacity */ + new_byte_pos = tty->echo_pos; + + /* + * Since the buffer start position needs to be advanced, + * be sure to step by a whole operation byte group. + */ + if (tty->echo_buf[tty->echo_pos] == ECHO_OP_START) { + if (tty->echo_buf[(tty->echo_pos + 1) & + (N_TTY_BUF_SIZE - 1)] == + ECHO_OP_ERASE_TAB) { + tty->echo_pos += 3; + tty->echo_cnt -= 2; + } else { + tty->echo_pos += 2; + tty->echo_cnt -= 1; + } + } else { + tty->echo_pos++; + } + tty->echo_pos &= N_TTY_BUF_SIZE - 1; + + tty->echo_overrun = 1; + } else { + new_byte_pos = tty->echo_pos + tty->echo_cnt; + new_byte_pos &= N_TTY_BUF_SIZE - 1; + tty->echo_cnt++; + } + + tty->echo_buf[new_byte_pos] = c; +} + +/** + * echo_move_back_col - add operation to move back a column + * @tty: terminal device + * + * Add an operation to the echo buffer to move back one column. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_move_back_col(struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty); + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_set_canon_col - add operation to set the canon column + * @tty: terminal device + * + * Add an operation to the echo buffer to set the canon column + * to the current column. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_set_canon_col(struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_SET_CANON_COL, tty); + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_erase_tab - add operation to erase a tab + * @num_chars: number of character columns already used + * @after_tab: true if num_chars starts after a previous tab + * @tty: terminal device + * + * Add an operation to the echo buffer to erase a tab. + * + * Called by the eraser function, which knows how many character + * columns have been used since either a previous tab or the start + * of input. This information will be used later, along with + * canon column (if applicable), to go back the correct number + * of columns. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_erase_tab(unsigned int num_chars, int after_tab, + struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_ERASE_TAB, tty); + + /* We only need to know this modulo 8 (tab spacing) */ + num_chars &= 7; + + /* Set the high bit as a flag if num_chars is after a previous tab */ + if (after_tab) + num_chars |= 0x80; + + add_echo_byte(num_chars, tty); + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_char_raw - echo a character raw * @c: unicode byte to echo * @tty: terminal device * * Echo user input back onto the screen. This must be called only when * L_ECHO(tty) is true. Called from the driver receive_buf path. * - * Relies on BKL for tty column locking + * This variant does not treat control characters specially. + * + * Locking: echo_lock to protect the echo buffer + */ + +static void echo_char_raw(unsigned char c, struct tty_struct *tty) +{ + mutex_lock(&tty->echo_lock); + + if (c == ECHO_OP_START) { + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_START, tty); + } else { + add_echo_byte(c, tty); + } + + mutex_unlock(&tty->echo_lock); +} + +/** + * echo_char - echo a character + * @c: unicode byte to echo + * @tty: terminal device + * + * Echo user input back onto the screen. This must be called only when + * L_ECHO(tty) is true. Called from the driver receive_buf path. + * + * This variant tags control characters to be possibly echoed as + * as "^X" (where X is the letter representing the control char). + * + * Locking: echo_lock to protect the echo buffer */ static void echo_char(unsigned char c, struct tty_struct *tty) { - if (L_ECHOCTL(tty) && iscntrl(c) && c != '\t') { - tty_put_char(tty, '^'); - tty_put_char(tty, c ^ 0100); - tty->column += 2; - } else - opost(c, tty); + mutex_lock(&tty->echo_lock); + + if (c == ECHO_OP_START) { + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(ECHO_OP_START, tty); + } else { + if (iscntrl(c) && c != '\t') + add_echo_byte(ECHO_OP_START, tty); + add_echo_byte(c, tty); + } + + mutex_unlock(&tty->echo_lock); } /** - * finsh_erasing - complete erase + * finish_erasing - complete erase * @tty: tty doing the erase - * - * Relies on BKL for tty column locking */ + static inline void finish_erasing(struct tty_struct *tty) { if (tty->erasing) { - tty_put_char(tty, '/'); - tty->column++; + echo_char_raw('/', tty); tty->erasing = 0; } } @@ -460,7 +861,7 @@ static inline void finish_erasing(struct tty_struct *tty) * present in the stream from the driver layer. Handles the complexities * of UTF-8 multibyte symbols. * - * Locking: read_lock for tty buffers, BKL for column/erasing state + * Locking: read_lock for tty buffers */ static void eraser(unsigned char c, struct tty_struct *tty) @@ -471,7 +872,7 @@ static void eraser(unsigned char c, struct tty_struct *tty) /* FIXME: locking needed ? */ if (tty->read_head == tty->canon_head) { - /* opost('\a', tty); */ /* what do you think? */ + /* process_output('\a', tty); */ /* what do you think? */ return; } if (c == ERASE_CHAR(tty)) @@ -497,7 +898,7 @@ static void eraser(unsigned char c, struct tty_struct *tty) echo_char(KILL_CHAR(tty), tty); /* Add a newline if ECHOK is on and ECHOKE is off. */ if (L_ECHOK(tty)) - opost('\n', tty); + echo_char_raw('\n', tty); return; } kill_type = KILL; @@ -533,67 +934,61 @@ static void eraser(unsigned char c, struct tty_struct *tty) if (L_ECHO(tty)) { if (L_ECHOPRT(tty)) { if (!tty->erasing) { - tty_put_char(tty, '\\'); - tty->column++; + echo_char_raw('\\', tty); tty->erasing = 1; } /* if cnt > 1, output a multi-byte character */ echo_char(c, tty); while (--cnt > 0) { head = (head+1) & (N_TTY_BUF_SIZE-1); - tty_put_char(tty, tty->read_buf[head]); + echo_char_raw(tty->read_buf[head], tty); + echo_move_back_col(tty); } } else if (kill_type == ERASE && !L_ECHOE(tty)) { echo_char(ERASE_CHAR(tty), tty); } else if (c == '\t') { - unsigned int col = tty->canon_column; - unsigned long tail = tty->canon_head; - - /* Find the column of the last char. */ - while (tail != tty->read_head) { + unsigned int num_chars = 0; + int after_tab = 0; + unsigned long tail = tty->read_head; + + /* + * Count the columns used for characters + * since the start of input or after a + * previous tab. + * This info is used to go back the correct + * number of columns. + */ + while (tail != tty->canon_head) { + tail = (tail-1) & (N_TTY_BUF_SIZE-1); c = tty->read_buf[tail]; - if (c == '\t') - col = (col | 7) + 1; - else if (iscntrl(c)) { + if (c == '\t') { + after_tab = 1; + break; + } else if (iscntrl(c)) { if (L_ECHOCTL(tty)) - col += 2; - } else if (!is_continuation(c, tty)) - col++; - tail = (tail+1) & (N_TTY_BUF_SIZE-1); - } - - /* should never happen */ - if (tty->column > 0x80000000) - tty->column = 0; - - /* Now backup to that column. */ - while (tty->column > col) { - /* Can't use opost here. */ - tty_put_char(tty, '\b'); - if (tty->column > 0) - tty->column--; + num_chars += 2; + } else if (!is_continuation(c, tty)) { + num_chars++; + } } + echo_erase_tab(num_chars, after_tab, tty); } else { if (iscntrl(c) && L_ECHOCTL(tty)) { - tty_put_char(tty, '\b'); - tty_put_char(tty, ' '); - tty_put_char(tty, '\b'); - if (tty->column > 0) - tty->column--; + echo_char_raw('\b', tty); + echo_char_raw(' ', tty); + echo_char_raw('\b', tty); } if (!iscntrl(c) || L_ECHOCTL(tty)) { - tty_put_char(tty, '\b'); - tty_put_char(tty, ' '); - tty_put_char(tty, '\b'); - if (tty->column > 0) - tty->column--; + echo_char_raw('\b', tty); + echo_char_raw(' ', tty); + echo_char_raw('\b', tty); } } } if (kill_type == ERASE) break; } - if (tty->read_head == tty->canon_head) + if (tty->read_head == tty->canon_head && L_ECHO(tty)) finish_erasing(tty); } @@ -712,6 +1107,7 @@ static inline void n_tty_receive_parity_error(struct tty_struct *tty, static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) { unsigned long flags; + int parmrk; if (tty->raw) { put_tty_queue(c, tty); @@ -721,18 +1117,21 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) if (I_ISTRIP(tty)) c &= 0x7f; if (I_IUCLC(tty) && L_IEXTEN(tty)) - c=tolower(c); + c = tolower(c); if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && - ((I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty)) || - c == INTR_CHAR(tty) || c == QUIT_CHAR(tty) || c == SUSP_CHAR(tty))) + I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) && + c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) { start_tty(tty); + process_echoes(tty); + } if (tty->closing) { if (I_IXON(tty)) { - if (c == START_CHAR(tty)) + if (c == START_CHAR(tty)) { start_tty(tty); - else if (c == STOP_CHAR(tty)) + process_echoes(tty); + } else if (c == STOP_CHAR(tty)) stop_tty(tty); } return; @@ -745,19 +1144,23 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) * up. */ if (!test_bit(c, tty->process_char_map) || tty->lnext) { - finish_erasing(tty); tty->lnext = 0; + parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; + if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { + /* beep if no space */ + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } if (L_ECHO(tty)) { - if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { - tty_put_char(tty, '\a'); /* beep if no space */ - return; - } + finish_erasing(tty); /* Record the column of first canon char. */ if (tty->canon_head == tty->read_head) - tty->canon_column = tty->column; + echo_set_canon_col(tty); echo_char(c, tty); + process_echoes(tty); } - if (I_PARMRK(tty) && c == (unsigned char) '\377') + if (parmrk) put_tty_queue(c, tty); put_tty_queue(c, tty); return; @@ -766,6 +1169,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) if (I_IXON(tty)) { if (c == START_CHAR(tty)) { start_tty(tty); + process_echoes(tty); return; } if (c == STOP_CHAR(tty)) { @@ -786,7 +1190,6 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) if (c == SUSP_CHAR(tty)) { send_signal: /* - * Echo character, and then send the signal. * Note that we do not use isig() here because we want * the order to be: * 1) flush, 2) echo, 3) signal @@ -795,8 +1198,12 @@ send_signal: n_tty_flush_buffer(tty); tty_driver_flush_buffer(tty); } - if (L_ECHO(tty)) + if (I_IXON(tty)) + start_tty(tty); + if (L_ECHO(tty)) { echo_char(c, tty); + process_echoes(tty); + } if (tty->pgrp) kill_pgrp(tty->pgrp, signal, 1); return; @@ -815,6 +1222,7 @@ send_signal: if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) || (c == WERASE_CHAR(tty) && L_IEXTEN(tty))) { eraser(c, tty); + process_echoes(tty); return; } if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) { @@ -822,8 +1230,9 @@ send_signal: if (L_ECHO(tty)) { finish_erasing(tty); if (L_ECHOCTL(tty)) { - tty_put_char(tty, '^'); - tty_put_char(tty, '\b'); + echo_char_raw('^', tty); + echo_char_raw('\b', tty); + process_echoes(tty); } } return; @@ -834,22 +1243,29 @@ send_signal: finish_erasing(tty); echo_char(c, tty); - opost('\n', tty); + echo_char_raw('\n', tty); while (tail != tty->read_head) { echo_char(tty->read_buf[tail], tty); tail = (tail+1) & (N_TTY_BUF_SIZE-1); } + process_echoes(tty); return; } if (c == '\n') { + if (tty->read_cnt >= N_TTY_BUF_SIZE) { + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } if (L_ECHO(tty) || L_ECHONL(tty)) { - if (tty->read_cnt >= N_TTY_BUF_SIZE-1) - tty_put_char(tty, '\a'); - opost('\n', tty); + echo_char_raw('\n', tty); + process_echoes(tty); } goto handle_newline; } if (c == EOF_CHAR(tty)) { + if (tty->read_cnt >= N_TTY_BUF_SIZE) + return; if (tty->canon_head != tty->read_head) set_bit(TTY_PUSH, &tty->flags); c = __DISABLED_CHAR; @@ -857,22 +1273,28 @@ send_signal: } if ((c == EOL_CHAR(tty)) || (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { + parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) + ? 1 : 0; + if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) { + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } /* * XXX are EOL_CHAR and EOL2_CHAR echoed?!? */ if (L_ECHO(tty)) { - if (tty->read_cnt >= N_TTY_BUF_SIZE-1) - tty_put_char(tty, '\a'); /* Record the column of first canon char. */ if (tty->canon_head == tty->read_head) - tty->canon_column = tty->column; + echo_set_canon_col(tty); echo_char(c, tty); + process_echoes(tty); } /* * XXX does PARMRK doubling happen for * EOL_CHAR and EOL2_CHAR? */ - if (I_PARMRK(tty) && c == (unsigned char) '\377') + if (parmrk) put_tty_queue(c, tty); handle_newline: @@ -889,23 +1311,27 @@ handle_newline: } } - finish_erasing(tty); + parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; + if (tty->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) { + /* beep if no space */ + if (L_ECHO(tty)) + process_output('\a', tty); + return; + } if (L_ECHO(tty)) { - if (tty->read_cnt >= N_TTY_BUF_SIZE-1) { - tty_put_char(tty, '\a'); /* beep if no space */ - return; - } + finish_erasing(tty); if (c == '\n') - opost('\n', tty); + echo_char_raw('\n', tty); else { /* Record the column of first canon char. */ if (tty->canon_head == tty->read_head) - tty->canon_column = tty->column; + echo_set_canon_col(tty); echo_char(c, tty); } + process_echoes(tty); } - if (I_PARMRK(tty) && c == (unsigned char) '\377') + if (parmrk) put_tty_queue(c, tty); put_tty_queue(c, tty); @@ -923,10 +1349,11 @@ handle_newline: static void n_tty_write_wakeup(struct tty_struct *tty) { - if (tty->fasync) { - set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + /* Write out any echoed characters that are still pending */ + process_echoes(tty); + + if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) kill_fasync(&tty->fasync, SIGIO, POLL_OUT); - } } /** @@ -1134,6 +1561,10 @@ static void n_tty_close(struct tty_struct *tty) free_buf(tty->read_buf); tty->read_buf = NULL; } + if (tty->echo_buf) { + free_buf(tty->echo_buf); + tty->echo_buf = NULL; + } } /** @@ -1151,13 +1582,19 @@ static int n_tty_open(struct tty_struct *tty) if (!tty) return -EINVAL; - /* This one is ugly. Currently a malloc failure here can panic */ + /* These are ugly. Currently a malloc failure here can panic */ if (!tty->read_buf) { tty->read_buf = alloc_buf(); if (!tty->read_buf) return -ENOMEM; } + if (!tty->echo_buf) { + tty->echo_buf = alloc_buf(); + if (!tty->echo_buf) + return -ENOMEM; + } memset(tty->read_buf, 0, N_TTY_BUF_SIZE); + memset(tty->echo_buf, 0, N_TTY_BUF_SIZE); reset_buffer_flags(tty); tty->column = 0; n_tty_set_termios(tty, NULL); @@ -1487,16 +1924,23 @@ do_it_again: * @buf: userspace buffer pointer * @nr: size of I/O * - * Write function of the terminal device. This is serialized with + * Write function of the terminal device. This is serialized with * respect to other write callers but not to termios changes, reads - * and other such events. We must be careful with N_TTY as the receive - * code will echo characters, thus calling driver write methods. + * and other such events. Since the receive code will echo characters, + * thus calling driver write methods, the output_lock is used in + * the output processing functions called here as well as in the + * echo processing function to protect the column state and space + * left in the buffer. * * This code must be sure never to sleep through a hangup. + * + * Locking: output_lock to protect column state and space left + * (note that the process_output*() functions take this + * lock themselves) */ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, - const unsigned char *buf, size_t nr) + const unsigned char *buf, size_t nr) { const unsigned char *b = buf; DECLARE_WAITQUEUE(wait, current); @@ -1510,6 +1954,9 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, return retval; } + /* Write out any echoed characters that are still pending */ + process_echoes(tty); + add_wait_queue(&tty->write_wait, &wait); while (1) { set_current_state(TASK_INTERRUPTIBLE); @@ -1523,7 +1970,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, } if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) { while (nr > 0) { - ssize_t num = opost_block(tty, b, nr); + ssize_t num = process_output_block(tty, b, nr); if (num < 0) { if (num == -EAGAIN) break; @@ -1535,7 +1982,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, if (nr == 0) break; c = *b; - if (opost(c, tty) < 0) + if (process_output(c, tty) < 0) break; b++; nr--; } @@ -1565,6 +2012,8 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, break_out: __set_current_state(TASK_RUNNING); remove_wait_queue(&tty->write_wait, &wait); + if (b - buf != nr && tty->fasync) + set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); return (b - buf) ? b - buf : retval; } @@ -1663,4 +2112,3 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = { .receive_buf = n_tty_receive_buf, .write_wakeup = n_tty_write_wakeup }; - |
