drivers/staging/speakup/selection.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/slab.h> /* for kmalloc */
   3 #include <linux/consolemap.h>
   4 #include <linux/interrupt.h>
   5 #include <linux/sched.h>
   6 #include <linux/device.h> /* for dev_warn */
   7 #include <linux/selection.h>
   8 #include <linux/workqueue.h>
   9 #include <linux/tty.h>
  10 #include <linux/tty_flip.h>
  11 #include <linux/atomic.h>
  12
  13 #include "speakup.h"
  14
  15 /* ------ cut and paste ----- */
  16 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
  17 #define ishardspace(c)      ((c) == ' ')
  18
  19 unsigned short spk_xs, spk_ys, spk_xe, spk_ye; /* our region points */
  20
  21 /* Variables for selection control. */
  22 /* must not be deallocated */
  23 struct vc_data *spk_sel_cons;
  24 /* cleared by clear_selection */
  25 static int sel_start = -1;
  26 static int sel_end;
  27 static int sel_buffer_lth;
  28 static char *sel_buffer;
  29
  30 static unsigned char sel_pos(int n)
  31 {
  32         return inverse_translate(spk_sel_cons,
  33                 screen_glyph(spk_sel_cons, n), 0);
  34 }
  35
  36 void speakup_clear_selection(void)
  37 {
  38         sel_start = -1;
  39 }
  40
  41 /* does screen address p correspond to character at LH/RH edge of screen? */
  42 static int atedge(const int p, int size_row)
  43 {
  44         return !(p % size_row) || !((p + 2) % size_row);
  45 }
  46
  47 /* constrain v such that v <= u */
  48 static unsigned short limit(const unsigned short v, const unsigned short u)
  49 {
  50         return (v > u) ? u : v;
  51 }
  52
  53 int speakup_set_selection(struct tty_struct *tty)
  54 {
  55         int new_sel_start, new_sel_end;
  56         char *bp, *obp;
  57         int i, ps, pe;
  58         struct vc_data *vc = vc_cons[fg_console].d;
  59
  60         spk_xs = limit(spk_xs, vc->vc_cols - 1);
  61         spk_ys = limit(spk_ys, vc->vc_rows - 1);
  62         spk_xe = limit(spk_xe, vc->vc_cols - 1);
  63         spk_ye = limit(spk_ye, vc->vc_rows - 1);
  64         ps = spk_ys * vc->vc_size_row + (spk_xs << 1);
  65         pe = spk_ye * vc->vc_size_row + (spk_xe << 1);
  66
  67         if (ps > pe)    /* make sel_start <= sel_end */
  68                 swap(ps, pe);
  69
  70         if (spk_sel_cons != vc_cons[fg_console].d) {
  71                 speakup_clear_selection();
  72                 spk_sel_cons = vc_cons[fg_console].d;
  73                 dev_warn(tty->dev,
  74                          "Selection: mark console not the same as cut\n");
  75                 return -EINVAL;
  76         }
  77
  78         new_sel_start = ps;
  79         new_sel_end = pe;
  80
  81         /* select to end of line if on trailing space */
  82         if (new_sel_end > new_sel_start &&
  83             !atedge(new_sel_end, vc->vc_size_row) &&
  84             ishardspace(sel_pos(new_sel_end))) {
  85                 for (pe = new_sel_end + 2; ; pe += 2)
  86                         if (!ishardspace(sel_pos(pe)) ||
  87                             atedge(pe, vc->vc_size_row))
  88                                 break;
  89                 if (ishardspace(sel_pos(pe)))
  90                         new_sel_end = pe;
  91         }
  92         if ((new_sel_start == sel_start) && (new_sel_end == sel_end))
  93                 return 0; /* no action required */
  94
  95         sel_start = new_sel_start;
  96         sel_end = new_sel_end;
  97         /* Allocate a new buffer before freeing the old one ... */
  98         bp = kmalloc((sel_end - sel_start) / 2 + 1, GFP_ATOMIC);
  99         if (!bp) {
 100                 speakup_clear_selection();
 101                 return -ENOMEM;
 102         }
 103         kfree(sel_buffer);
 104         sel_buffer = bp;
 105
 106         obp = bp;
 107         for (i = sel_start; i <= sel_end; i += 2) {
 108                 *bp = sel_pos(i);
 109                 if (!ishardspace(*bp++))
 110                         obp = bp;
 111                 if (!((i + 2) % vc->vc_size_row)) {
 112                         /* strip trailing blanks from line and add newline,
 113                          * unless non-space at end of line.
 114                          */
 115                         if (obp != bp) {
 116                                 bp = obp;
 117                                 *bp++ = '\r';
 118                         }
 119                         obp = bp;
 120                 }
 121         }
 122         sel_buffer_lth = bp - sel_buffer;
 123         return 0;
 124 }
 125
 126 struct speakup_paste_work {
 127         struct work_struct work;
 128         struct tty_struct *tty;
 129 };
 130
 131 static void __speakup_paste_selection(struct work_struct *work)
 132 {
 133         struct speakup_paste_work *spw =
 134                 container_of(work, struct speakup_paste_work, work);
 135         struct tty_struct *tty = xchg(&spw->tty, NULL);
 136         struct vc_data *vc = (struct vc_data *)tty->driver_data;
 137         int pasted = 0, count;
 138         struct tty_ldisc *ld;
 139         DECLARE_WAITQUEUE(wait, current);
 140
 141         ld = tty_ldisc_ref(tty);
 142         if (!ld)
 143                 goto tty_unref;
 144         tty_buffer_lock_exclusive(&vc->port);
 145
 146         add_wait_queue(&vc->paste_wait, &wait);
 147         while (sel_buffer && sel_buffer_lth > pasted) {
 148                 set_current_state(TASK_INTERRUPTIBLE);
 149                 if (tty_throttled(tty)) {
 150                         schedule();
 151                         continue;
 152                 }
 153                 count = sel_buffer_lth - pasted;
 154                 count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 155                                               count);
 156                 pasted += count;
 157         }
 158         remove_wait_queue(&vc->paste_wait, &wait);
 159         __set_current_state(TASK_RUNNING);
 160
 161         tty_buffer_unlock_exclusive(&vc->port);
 162         tty_ldisc_deref(ld);
 163 tty_unref:
 164         tty_kref_put(tty);
 165 }
 166
 167 static struct speakup_paste_work speakup_paste_work = {
 168         .work = __WORK_INITIALIZER(speakup_paste_work.work,
 169                                    __speakup_paste_selection)
 170 };
 171
 172 int speakup_paste_selection(struct tty_struct *tty)
 173 {
 174         if (cmpxchg(&speakup_paste_work.tty, NULL, tty))
 175                 return -EBUSY;
 176
 177         tty_kref_get(tty);
 178         schedule_work_on(WORK_CPU_UNBOUND, &speakup_paste_work.work);
 179         return 0;
 180 }
 181
 182 void speakup_cancel_paste(void)
 183 {
 184         cancel_work_sync(&speakup_paste_work.work);
 185         tty_kref_put(speakup_paste_work.tty);
 186 }