diff options
Diffstat (limited to 'drivers/tty/vt/selection.c')
| -rw-r--r-- | drivers/tty/vt/selection.c | 421 |
1 files changed, 421 insertions, 0 deletions
diff --git a/drivers/tty/vt/selection.c b/drivers/tty/vt/selection.c new file mode 100644 index 000000000..6ef22f01c --- /dev/null +++ b/drivers/tty/vt/selection.c @@ -0,0 +1,421 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This module exports the functions: + * + * 'int set_selection_user(struct tiocl_selection __user *, + * struct tty_struct *)' + * 'int set_selection_kernel(struct tiocl_selection *, struct tty_struct *)' + * 'void clear_selection(void)' + * 'int paste_selection(struct tty_struct *)' + * 'int sel_loadlut(char __user *)' + * + * Now that /dev/vcs exists, most of this can disappear again. + */ + +#include <linux/module.h> +#include <linux/tty.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/types.h> + +#include <linux/uaccess.h> + +#include <linux/kbd_kern.h> +#include <linux/vt_kern.h> +#include <linux/consolemap.h> +#include <linux/selection.h> +#include <linux/tiocl.h> +#include <linux/console.h> +#include <linux/tty_flip.h> + +#include <linux/sched/signal.h> + +/* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */ +#define is_space_on_vt(c) ((c) == ' ') + +/* FIXME: all this needs locking */ +static struct vc_selection { + struct mutex lock; + struct vc_data *cons; /* must not be deallocated */ + char *buffer; + unsigned int buf_len; + volatile int start; /* cleared by clear_selection */ + int end; +} vc_sel = { + .lock = __MUTEX_INITIALIZER(vc_sel.lock), + .start = -1, +}; + +/* clear_selection, highlight and highlight_pointer can be called + from interrupt (via scrollback/front) */ + +/* set reverse video on characters s-e of console with selection. */ +static inline void highlight(const int s, const int e) +{ + invert_screen(vc_sel.cons, s, e-s+2, true); +} + +/* use complementary color to show the pointer */ +static inline void highlight_pointer(const int where) +{ + complement_pos(vc_sel.cons, where); +} + +static u32 +sel_pos(int n, bool unicode) +{ + if (unicode) + return screen_glyph_unicode(vc_sel.cons, n / 2); + return inverse_translate(vc_sel.cons, screen_glyph(vc_sel.cons, n), + false); +} + +/** + * clear_selection - remove current selection + * + * Remove the current selection highlight, if any from the console + * holding the selection. The caller must hold the console lock. + */ +void clear_selection(void) +{ + highlight_pointer(-1); /* hide the pointer */ + if (vc_sel.start != -1) { + highlight(vc_sel.start, vc_sel.end); + vc_sel.start = -1; + } +} +EXPORT_SYMBOL_GPL(clear_selection); + +bool vc_is_sel(struct vc_data *vc) +{ + return vc == vc_sel.cons; +} + +/* + * User settable table: what characters are to be considered alphabetic? + * 128 bits. Locked by the console lock. + */ +static u32 inwordLut[]={ + 0x00000000, /* control chars */ + 0x03FFE000, /* digits and "-./" */ + 0x87FFFFFE, /* uppercase and '_' */ + 0x07FFFFFE, /* lowercase */ +}; + +static inline int inword(const u32 c) +{ + return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1); +} + +/** + * sel_loadlut() - load the LUT table + * @p: user table + * + * Load the LUT table from user space. The caller must hold the console + * lock. Make a temporary copy so a partial update doesn't make a mess. + */ +int sel_loadlut(char __user *p) +{ + u32 tmplut[ARRAY_SIZE(inwordLut)]; + if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut))) + return -EFAULT; + memcpy(inwordLut, tmplut, sizeof(inwordLut)); + return 0; +} + +/* does screen address p correspond to character at LH/RH edge of screen? */ +static inline int atedge(const int p, int size_row) +{ + return (!(p % size_row) || !((p + 2) % size_row)); +} + +/* stores the char in UTF8 and returns the number of bytes used (1-4) */ +static int store_utf8(u32 c, char *p) +{ + if (c < 0x80) { + /* 0******* */ + p[0] = c; + return 1; + } else if (c < 0x800) { + /* 110***** 10****** */ + p[0] = 0xc0 | (c >> 6); + p[1] = 0x80 | (c & 0x3f); + return 2; + } else if (c < 0x10000) { + /* 1110**** 10****** 10****** */ + p[0] = 0xe0 | (c >> 12); + p[1] = 0x80 | ((c >> 6) & 0x3f); + p[2] = 0x80 | (c & 0x3f); + return 3; + } else if (c < 0x110000) { + /* 11110*** 10****** 10****** 10****** */ + p[0] = 0xf0 | (c >> 18); + p[1] = 0x80 | ((c >> 12) & 0x3f); + p[2] = 0x80 | ((c >> 6) & 0x3f); + p[3] = 0x80 | (c & 0x3f); + return 4; + } else { + /* outside Unicode, replace with U+FFFD */ + p[0] = 0xef; + p[1] = 0xbf; + p[2] = 0xbd; + return 3; + } +} + +/** + * set_selection_user - set the current selection. + * @sel: user selection info + * @tty: the console tty + * + * Invoked by the ioctl handle for the vt layer. + * + * The entire selection process is managed under the console_lock. It's + * a lot under the lock but its hardly a performance path + */ +int set_selection_user(const struct tiocl_selection __user *sel, + struct tty_struct *tty) +{ + struct tiocl_selection v; + + if (copy_from_user(&v, sel, sizeof(*sel))) + return -EFAULT; + + return set_selection_kernel(&v, tty); +} + +static int vc_selection_store_chars(struct vc_data *vc, bool unicode) +{ + char *bp, *obp; + unsigned int i; + + /* Allocate a new buffer before freeing the old one ... */ + /* chars can take up to 4 bytes with unicode */ + bp = kmalloc_array((vc_sel.end - vc_sel.start) / 2 + 1, unicode ? 4 : 1, + GFP_KERNEL | __GFP_NOWARN); + if (!bp) { + printk(KERN_WARNING "selection: kmalloc() failed\n"); + clear_selection(); + return -ENOMEM; + } + kfree(vc_sel.buffer); + vc_sel.buffer = bp; + + obp = bp; + for (i = vc_sel.start; i <= vc_sel.end; i += 2) { + u32 c = sel_pos(i, unicode); + if (unicode) + bp += store_utf8(c, bp); + else + *bp++ = c; + if (!is_space_on_vt(c)) + obp = bp; + if (!((i + 2) % vc->vc_size_row)) { + /* strip trailing blanks from line and add newline, + unless non-space at end of line. */ + if (obp != bp) { + bp = obp; + *bp++ = '\r'; + } + obp = bp; + } + } + vc_sel.buf_len = bp - vc_sel.buffer; + + return 0; +} + +static int vc_do_selection(struct vc_data *vc, unsigned short mode, int ps, + int pe) +{ + int new_sel_start, new_sel_end, spc; + bool unicode = vt_do_kdgkbmode(fg_console) == K_UNICODE; + + switch (mode) { + case TIOCL_SELCHAR: /* character-by-character selection */ + new_sel_start = ps; + new_sel_end = pe; + break; + case TIOCL_SELWORD: /* word-by-word selection */ + spc = is_space_on_vt(sel_pos(ps, unicode)); + for (new_sel_start = ps; ; ps -= 2) { + if ((spc && !is_space_on_vt(sel_pos(ps, unicode))) || + (!spc && !inword(sel_pos(ps, unicode)))) + break; + new_sel_start = ps; + if (!(ps % vc->vc_size_row)) + break; + } + + spc = is_space_on_vt(sel_pos(pe, unicode)); + for (new_sel_end = pe; ; pe += 2) { + if ((spc && !is_space_on_vt(sel_pos(pe, unicode))) || + (!spc && !inword(sel_pos(pe, unicode)))) + break; + new_sel_end = pe; + if (!((pe + 2) % vc->vc_size_row)) + break; + } + break; + case TIOCL_SELLINE: /* line-by-line selection */ + new_sel_start = rounddown(ps, vc->vc_size_row); + new_sel_end = rounddown(pe, vc->vc_size_row) + + vc->vc_size_row - 2; + break; + case TIOCL_SELPOINTER: + highlight_pointer(pe); + return 0; + default: + return -EINVAL; + } + + /* remove the pointer */ + highlight_pointer(-1); + + /* select to end of line if on trailing space */ + if (new_sel_end > new_sel_start && + !atedge(new_sel_end, vc->vc_size_row) && + is_space_on_vt(sel_pos(new_sel_end, unicode))) { + for (pe = new_sel_end + 2; ; pe += 2) + if (!is_space_on_vt(sel_pos(pe, unicode)) || + atedge(pe, vc->vc_size_row)) + break; + if (is_space_on_vt(sel_pos(pe, unicode))) + new_sel_end = pe; + } + if (vc_sel.start == -1) /* no current selection */ + highlight(new_sel_start, new_sel_end); + else if (new_sel_start == vc_sel.start) + { + if (new_sel_end == vc_sel.end) /* no action required */ + return 0; + else if (new_sel_end > vc_sel.end) /* extend to right */ + highlight(vc_sel.end + 2, new_sel_end); + else /* contract from right */ + highlight(new_sel_end + 2, vc_sel.end); + } + else if (new_sel_end == vc_sel.end) + { + if (new_sel_start < vc_sel.start) /* extend to left */ + highlight(new_sel_start, vc_sel.start - 2); + else /* contract from left */ + highlight(vc_sel.start, new_sel_start - 2); + } + else /* some other case; start selection from scratch */ + { + clear_selection(); + highlight(new_sel_start, new_sel_end); + } + vc_sel.start = new_sel_start; + vc_sel.end = new_sel_end; + + return vc_selection_store_chars(vc, unicode); +} + +static int vc_selection(struct vc_data *vc, struct tiocl_selection *v, + struct tty_struct *tty) +{ + int ps, pe; + + poke_blanked_console(); + + if (v->sel_mode == TIOCL_SELCLEAR) { + /* useful for screendump without selection highlights */ + clear_selection(); + return 0; + } + + v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1); + v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1); + v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1); + v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1); + + if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) { + mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs, + v->ys); + return 0; + } + + ps = v->ys * vc->vc_size_row + (v->xs << 1); + pe = v->ye * vc->vc_size_row + (v->xe << 1); + if (ps > pe) /* make vc_sel.start <= vc_sel.end */ + swap(ps, pe); + + if (vc_sel.cons != vc) { + clear_selection(); + vc_sel.cons = vc; + } + + return vc_do_selection(vc, v->sel_mode, ps, pe); +} + +int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty) +{ + int ret; + + mutex_lock(&vc_sel.lock); + console_lock(); + ret = vc_selection(vc_cons[fg_console].d, v, tty); + console_unlock(); + mutex_unlock(&vc_sel.lock); + + return ret; +} +EXPORT_SYMBOL_GPL(set_selection_kernel); + +/* Insert the contents of the selection buffer into the + * queue of the tty associated with the current console. + * Invoked by ioctl(). + * + * Locking: called without locks. Calls the ldisc wrongly with + * unsafe methods, + */ +int paste_selection(struct tty_struct *tty) +{ + struct vc_data *vc = tty->driver_data; + int pasted = 0; + unsigned int count; + struct tty_ldisc *ld; + DECLARE_WAITQUEUE(wait, current); + int ret = 0; + + console_lock(); + poke_blanked_console(); + console_unlock(); + + ld = tty_ldisc_ref_wait(tty); + if (!ld) + return -EIO; /* ldisc was hung up */ + tty_buffer_lock_exclusive(&vc->port); + + add_wait_queue(&vc->paste_wait, &wait); + mutex_lock(&vc_sel.lock); + while (vc_sel.buffer && vc_sel.buf_len > pasted) { + set_current_state(TASK_INTERRUPTIBLE); + if (signal_pending(current)) { + ret = -EINTR; + break; + } + if (tty_throttled(tty)) { + mutex_unlock(&vc_sel.lock); + schedule(); + mutex_lock(&vc_sel.lock); + continue; + } + __set_current_state(TASK_RUNNING); + count = vc_sel.buf_len - pasted; + count = tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL, + count); + pasted += count; + } + mutex_unlock(&vc_sel.lock); + remove_wait_queue(&vc->paste_wait, &wait); + __set_current_state(TASK_RUNNING); + + tty_buffer_unlock_exclusive(&vc->port); + tty_ldisc_deref(ld); + return ret; +} +EXPORT_SYMBOL_GPL(paste_selection); |