selection.c

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/*
 * This module exports the functions:
 *
 *     'int set_selection(struct tiocl_selection __user *, 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/slab.h>
#include <linux/types.h>

#include <asm/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>

/* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
#define isspace(c)  ((c) == ' ')

extern void poke_blanked_console(void);

/* FIXME: all this needs locking */
/* Variables for selection control. */
/* Use a dynamic buffer, instead of static (Dec 1994) */
struct vc_data *sel_cons;       /* must not be deallocated */
static int use_unicode;
static volatile int sel_start = -1;     /* cleared by clear_selection */
static int sel_end;
static int sel_buffer_lth;
static char *sel_buffer;

/* 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(sel_cons, s, e-s+2, 1);
}

/* use complementary color to show the pointer */
static inline void highlight_pointer(const int where)
{
    complement_pos(sel_cons, where);
}

static u16
sel_pos(int n)
{
    return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
                use_unicode);
}

void clear_selection(void)
{
    highlight_pointer(-1); /* hide the pointer */
    if (sel_start != -1) {
        highlight(sel_start, sel_end);
        sel_start = -1;
    }
}

/*
 * User settable table: what characters are to be considered alphabetic?
 * 256 bits. Locked by the console lock.
 */
static u32 inwordLut[8]={
  0x00000000, /* control chars     */
  0x03FF0000, /* digits            */
  0x87FFFFFE, /* uppercase and '_' */
  0x07FFFFFE, /* lowercase         */
  0x00000000,
  0x00000000,
  0xFF7FFFFF, /* latin-1 accented letters, not multiplication sign */
  0xFF7FFFFF  /* latin-1 accented letters, not division sign */
};

static inline int inword(const u16 c) {
    return c > 0xff || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
}

int sel_loadlut(char __user *p)
{
    u32 tmplut[8];
    if (copy_from_user(tmplut, (u32 __user *)(p+4), 32))
        return -EFAULT;
    memcpy(inwordLut, tmplut, 32);
    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));
}

/* constrain v such that v <= u */
static inline unsigned short limit(const unsigned short v, const unsigned short u)
{
    return (v > u) ? u : v;
}

/* stores the char in UTF8 and returns the number of bytes used (1-3) */
static int store_utf8(u16 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 {
        /* 1110**** 10****** 10****** */
        p[0] = 0xe0 | (c >> 12);
        p[1] = 0x80 | ((c >> 6) & 0x3f);
        p[2] = 0x80 | (c & 0x3f);
        return 3;
        }
}

int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
{
    struct vc_data *vc = vc_cons[fg_console].d;
    int sel_mode, new_sel_start, new_sel_end, spc;
    char *bp, *obp;
    int i, ps, pe, multiplier;
    u16 c;
    int mode;

    poke_blanked_console();

    { unsigned short xs, ys, xe, ye;

      if (!access_ok(VERIFY_READ, sel, sizeof(*sel)))
        return -EFAULT;
      __get_user(xs, &sel->xs);
      __get_user(ys, &sel->ys);
      __get_user(xe, &sel->xe);
      __get_user(ye, &sel->ye);
      __get_user(sel_mode, &sel->sel_mode);
      xs--; ys--; xe--; ye--;
      xs = limit(xs, vc->vc_cols - 1);
      ys = limit(ys, vc->vc_rows - 1);
      xe = limit(xe, vc->vc_cols - 1);
      ye = limit(ye, vc->vc_rows - 1);
      ps = ys * vc->vc_size_row + (xs << 1);
      pe = ye * vc->vc_size_row + (xe << 1);

      if (sel_mode == TIOCL_SELCLEAR) {
          /* useful for screendump without selection highlights */
          clear_selection();
          return 0;
      }

      if (mouse_reporting() && (sel_mode & TIOCL_SELMOUSEREPORT)) {
          mouse_report(tty, sel_mode & TIOCL_SELBUTTONMASK, xs, ys);
          return 0;
      }
        }

    if (ps > pe)    /* make sel_start <= sel_end */
    {
        int tmp = ps;
        ps = pe;
        pe = tmp;
    }

    if (sel_cons != vc_cons[fg_console].d) {
        clear_selection();
        sel_cons = vc_cons[fg_console].d;
    }
    mode = vt_do_kdgkbmode(fg_console);
    if (mode == K_UNICODE)
        use_unicode = 1;
    else
        use_unicode = 0;

    switch (sel_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 = isspace(sel_pos(ps));
            for (new_sel_start = ps; ; ps -= 2)
            {
                if ((spc && !isspace(sel_pos(ps))) ||
                    (!spc && !inword(sel_pos(ps))))
                    break;
                new_sel_start = ps;
                if (!(ps % vc->vc_size_row))
                    break;
            }
            spc = isspace(sel_pos(pe));
            for (new_sel_end = pe; ; pe += 2)
            {
                if ((spc && !isspace(sel_pos(pe))) ||
                    (!spc && !inword(sel_pos(pe))))
                    break;
                new_sel_end = pe;
                if (!((pe + 2) % vc->vc_size_row))
                    break;
            }
            break;
        case TIOCL_SELLINE: /* line-by-line selection */
            new_sel_start = ps - ps % vc->vc_size_row;
            new_sel_end = pe + vc->vc_size_row
                    - pe % 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) &&
        isspace(sel_pos(new_sel_end))) {
        for (pe = new_sel_end + 2; ; pe += 2)
            if (!isspace(sel_pos(pe)) ||
                atedge(pe, vc->vc_size_row))
                break;
        if (isspace(sel_pos(pe)))
            new_sel_end = pe;
    }
    if (sel_start == -1)    /* no current selection */
        highlight(new_sel_start, new_sel_end);
    else if (new_sel_start == sel_start)
    {
        if (new_sel_end == sel_end) /* no action required */
            return 0;
        else if (new_sel_end > sel_end) /* extend to right */
            highlight(sel_end + 2, new_sel_end);
        else                /* contract from right */
            highlight(new_sel_end + 2, sel_end);
    }
    else if (new_sel_end == sel_end)
    {
        if (new_sel_start < sel_start)  /* extend to left */
            highlight(new_sel_start, sel_start - 2);
        else                /* contract from left */
            highlight(sel_start, new_sel_start - 2);
    }
    else    /* some other case; start selection from scratch */
    {
        clear_selection();
        highlight(new_sel_start, new_sel_end);
    }
    sel_start = new_sel_start;
    sel_end = new_sel_end;

    /* Allocate a new buffer before freeing the old one ... */
    multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
    bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
    if (!bp) {
        printk(KERN_WARNING "selection: kmalloc() failed\n");
        clear_selection();
        return -ENOMEM;
    }
    kfree(sel_buffer);
    sel_buffer = bp;

    obp = bp;
    for (i = sel_start; i <= sel_end; i += 2) {
        c = sel_pos(i);
        if (use_unicode)
            bp += store_utf8(c, bp);
        else
            *bp++ = c;
        if (!isspace(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;
        }
    }
    sel_buffer_lth = bp - sel_buffer;
    return 0;
}

/* 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);


    console_lock();
    poke_blanked_console();
    console_unlock();

    /* FIXME: wtf is this supposed to achieve ? */
    ld = tty_ldisc_ref(tty);
    if (!ld)
        ld = tty_ldisc_ref_wait(tty);

    /* FIXME: this is completely unsafe */
    add_wait_queue(&vc->paste_wait, &wait);
    while (sel_buffer && sel_buffer_lth > pasted) {
        set_current_state(TASK_INTERRUPTIBLE);
        if (test_bit(TTY_THROTTLED, &tty->flags)) {
            schedule();
            continue;
        }
        count = sel_buffer_lth - pasted;
        count = min(count, tty->receive_room);
        tty->ldisc->ops->receive_buf(tty, sel_buffer + pasted,
                                NULL, count);
        pasted += count;
    }
    remove_wait_queue(&vc->paste_wait, &wait);
    __set_current_state(TASK_RUNNING);

    tty_ldisc_deref(ld);
    return 0;
}