drivers/char/selection.c

   1 /*
   2  * linux/drivers/char/selection.c
   3  *
   4  * This module exports the functions:
   5  *
   6  *     'int set_selection(const unsigned long arg)'
   7  *     'void clear_selection(void)'
   8  *     'int paste_selection(struct tty_struct *tty)'
   9  *     'int sel_loadlut(const unsigned long arg)'
  10  *
  11  * Now that /dev/vcs exists, most of this can disappear again.
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/tty.h>
  16 #include <linux/sched.h>
  17 #include <linux/mm.h>
  18 #include <linux/malloc.h>
  19 #include <linux/types.h>
  20
  21 #include <asm/uaccess.h>
  22
  23 #include <linux/vt_kern.h>
  24 #include <linux/consolemap.h>
  25 #include <linux/console_struct.h>
  26 #include <linux/selection.h>
  27
  28 #ifndef MIN
  29 #define MIN(a,b)        ((a) < (b) ? (a) : (b))
  30 #endif
  31
  32 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
  33 #define isspace(c)      ((c) == ' ')
  34
  35 extern void poke_blanked_console(void);
  36
  37 /* Variables for selection control. */
  38 /* Use a dynamic buffer, instead of static (Dec 1994) */
  39        int sel_cons = 0;                /* must not be disallocated */
  40 static volatile int sel_start = -1;     /* cleared by clear_selection */
  41 static int sel_end;
  42 static int sel_buffer_lth = 0;
  43 static char *sel_buffer = NULL;
  44
  45 /* clear_selection, highlight and highlight_pointer can be called
  46    from interrupt (via scrollback/front) */
  47
  48 /* set reverse video on characters s-e of console with selection. */
  49 inline static void
  50 highlight(const int s, const int e) {
  51         invert_screen(sel_cons, s, e-s+2, 1);
  52 }
  53
  54 /* use complementary color to show the pointer */
  55 inline static void
  56 highlight_pointer(const int where) {
  57         complement_pos(sel_cons, where);
  58 }
  59
  60 static unsigned char
  61 sel_pos(int n)
  62 {
  63         return inverse_translate(vc_cons[sel_cons].d, screen_glyph(sel_cons, n));
  64 }
  65
  66 /* remove the current selection highlight, if any,
  67    from the console holding the selection. */
  68 void
  69 clear_selection(void) {
  70         highlight_pointer(-1); /* hide the pointer */
  71         if (sel_start != -1) {
  72                 highlight(sel_start, sel_end);
  73                 sel_start = -1;
  74         }
  75 }
  76
  77 /*
  78  * User settable table: what characters are to be considered alphabetic?
  79  * 256 bits
  80  */
  81 static u32 inwordLut[8]={
  82   0x00000000, /* control chars     */
  83   0x03FF0000, /* digits            */
  84   0x87FFFFFE, /* uppercase and '_' */
  85   0x07FFFFFE, /* lowercase         */
  86   0x00000000,
  87   0x00000000,
  88   0xFF7FFFFF, /* latin-1 accented letters, not multiplication sign */
  89   0xFF7FFFFF  /* latin-1 accented letters, not division sign */
  90 };
  91
  92 static inline int inword(const unsigned char c) {
  93         return ( inwordLut[c>>5] >> (c & 0x1F) ) & 1;
  94 }
  95
  96 /* set inwordLut contents. Invoked by ioctl(). */
  97 int sel_loadlut(const unsigned long arg)
  98 {
  99         int err = -EFAULT;
 100
 101         if (!copy_from_user(inwordLut, (u32 *)(arg+4), 32))
 102                 err = 0;
 103         return err;
 104 }
 105
 106 /* does screen address p correspond to character at LH/RH edge of screen? */
 107 static inline int atedge(const int p, int size_row)
 108 {
 109         return (!(p % size_row) || !((p + 2) % size_row));
 110 }
 111
 112 /* constrain v such that v <= u */
 113 static inline unsigned short limit(const unsigned short v, const unsigned short u)
 114 {
 115         return (v > u) ? u : v;
 116 }
 117
 118 /* set the current selection. Invoked by ioctl() or by kernel code. */
 119 int set_selection(const unsigned long arg, struct tty_struct *tty, int user)
 120 {
 121         int sel_mode, new_sel_start, new_sel_end, spc;
 122         char *bp, *obp;
 123         int i, ps, pe;
 124         unsigned int currcons = fg_console;
 125
 126         unblank_screen();
 127         poke_blanked_console();
 128
 129         { unsigned short *args, xs, ys, xe, ye;
 130
 131           args = (unsigned short *)(arg + 1);
 132           if (user) {
 133                   int err;
 134                   err = verify_area(VERIFY_READ, args, sizeof(short) * 5);
 135                   if (err)
 136                         return err;
 137                   get_user(xs, args++);
 138                   get_user(ys, args++);
 139                   get_user(xe, args++);
 140                   get_user(ye, args++);
 141                   get_user(sel_mode, args);
 142           } else {
 143                   xs = *(args++); /* set selection from kernel */
 144                   ys = *(args++);
 145                   xe = *(args++);
 146                   ye = *(args++);
 147                   sel_mode = *args;
 148           }
 149           xs--; ys--; xe--; ye--;
 150           xs = limit(xs, video_num_columns - 1);
 151           ys = limit(ys, video_num_lines - 1);
 152           xe = limit(xe, video_num_columns - 1);
 153           ye = limit(ye, video_num_lines - 1);
 154           ps = ys * video_size_row + (xs << 1);
 155           pe = ye * video_size_row + (xe << 1);
 156
 157           if (sel_mode == 4) {
 158               /* useful for screendump without selection highlights */
 159               clear_selection();
 160               return 0;
 161           }
 162
 163           if (mouse_reporting() && (sel_mode & 16)) {
 164               mouse_report(tty, sel_mode & 15, xs, ys);
 165               return 0;
 166           }
 167         }
 168
 169         if (ps > pe)    /* make sel_start <= sel_end */
 170         {
 171                 int tmp = ps;
 172                 ps = pe;
 173                 pe = tmp;
 174         }
 175
 176         if (sel_cons != fg_console) {
 177                 clear_selection();
 178                 sel_cons = fg_console;
 179         }
 180
 181         switch (sel_mode)
 182         {
 183                 case 0: /* character-by-character selection */
 184                         new_sel_start = ps;
 185                         new_sel_end = pe;
 186                         break;
 187                 case 1: /* word-by-word selection */
 188                         spc = isspace(sel_pos(ps));
 189                         for (new_sel_start = ps; ; ps -= 2)
 190                         {
 191                                 if ((spc && !isspace(sel_pos(ps))) ||
 192                                     (!spc && !inword(sel_pos(ps))))
 193                                         break;
 194                                 new_sel_start = ps;
 195                                 if (!(ps % video_size_row))
 196                                         break;
 197                         }
 198                         spc = isspace(sel_pos(pe));
 199                         for (new_sel_end = pe; ; pe += 2)
 200                         {
 201                                 if ((spc && !isspace(sel_pos(pe))) ||
 202                                     (!spc && !inword(sel_pos(pe))))
 203                                         break;
 204                                 new_sel_end = pe;
 205                                 if (!((pe + 2) % video_size_row))
 206                                         break;
 207                         }
 208                         break;
 209                 case 2: /* line-by-line selection */
 210                         new_sel_start = ps - ps % video_size_row;
 211                         new_sel_end = pe + video_size_row
 212                                     - pe % video_size_row - 2;
 213                         break;
 214                 case 3:
 215                         highlight_pointer(pe);
 216                         return 0;
 217                 default:
 218                         return -EINVAL;
 219         }
 220
 221         /* remove the pointer */
 222         highlight_pointer(-1);
 223
 224         /* select to end of line if on trailing space */
 225         if (new_sel_end > new_sel_start &&
 226                 !atedge(new_sel_end, video_size_row) &&
 227                 isspace(sel_pos(new_sel_end))) {
 228                 for (pe = new_sel_end + 2; ; pe += 2)
 229                         if (!isspace(sel_pos(pe)) ||
 230                             atedge(pe, video_size_row))
 231                                 break;
 232                 if (isspace(sel_pos(pe)))
 233                         new_sel_end = pe;
 234         }
 235         if (sel_start == -1)    /* no current selection */
 236                 highlight(new_sel_start, new_sel_end);
 237         else if (new_sel_start == sel_start)
 238         {
 239                 if (new_sel_end == sel_end)     /* no action required */
 240                         return 0;
 241                 else if (new_sel_end > sel_end) /* extend to right */
 242                         highlight(sel_end + 2, new_sel_end);
 243                 else                            /* contract from right */
 244                         highlight(new_sel_end + 2, sel_end);
 245         }
 246         else if (new_sel_end == sel_end)
 247         {
 248                 if (new_sel_start < sel_start)  /* extend to left */
 249                         highlight(new_sel_start, sel_start - 2);
 250                 else                            /* contract from left */
 251                         highlight(sel_start, new_sel_start - 2);
 252         }
 253         else    /* some other case; start selection from scratch */
 254         {
 255                 clear_selection();
 256                 highlight(new_sel_start, new_sel_end);
 257         }
 258         sel_start = new_sel_start;
 259         sel_end = new_sel_end;
 260
 261         /* Allocate a new buffer before freeing the old one ... */
 262         bp = kmalloc((sel_end-sel_start)/2+1, GFP_KERNEL);
 263         if (!bp) {
 264                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 265                 clear_selection();
 266                 return -ENOMEM;
 267         }
 268         if (sel_buffer)
 269                 kfree(sel_buffer);
 270         sel_buffer = bp;
 271
 272         obp = bp;
 273         for (i = sel_start; i <= sel_end; i += 2) {
 274                 *bp = sel_pos(i);
 275                 if (!isspace(*bp++))
 276                         obp = bp;
 277                 if (! ((i + 2) % video_size_row)) {
 278                         /* strip trailing blanks from line and add newline,
 279                            unless non-space at end of line. */
 280                         if (obp != bp) {
 281                                 bp = obp;
 282                                 *bp++ = '\r';
 283                         }
 284                         obp = bp;
 285                 }
 286         }
 287         sel_buffer_lth = bp - sel_buffer;
 288         return 0;
 289 }
 290
 291 /* Insert the contents of the selection buffer into the
 292  * queue of the tty associated with the current console.
 293  * Invoked by ioctl().
 294  */
 295 int paste_selection(struct tty_struct *tty)
 296 {
 297         struct vt_struct *vt = (struct vt_struct *) tty->driver_data;
 298         int     pasted = 0, count;
 299         DECLARE_WAITQUEUE(wait, current);
 300
 301         poke_blanked_console();
 302         add_wait_queue(&vt->paste_wait, &wait);
 303         while (sel_buffer && sel_buffer_lth > pasted) {
 304                 set_current_state(TASK_INTERRUPTIBLE);
 305                 if (test_bit(TTY_THROTTLED, &tty->flags)) {
 306                         schedule();
 307                         continue;
 308                 }
 309                 count = sel_buffer_lth - pasted;
 310                 count = MIN(count, tty->ldisc.receive_room(tty));
 311                 tty->ldisc.receive_buf(tty, sel_buffer + pasted, 0, count);
 312                 pasted += count;
 313         }
 314         remove_wait_queue(&vt->paste_wait, &wait);
 315         current->state = TASK_RUNNING;
 316         return 0;
 317 }
 318
 319 EXPORT_SYMBOL(set_selection);
 320 EXPORT_SYMBOL(paste_selection);