drivers/tty/vt/selection.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This module exports the functions:
   4  *
   5  *     'int set_selection_user(struct tiocl_selection __user *,
   6  *                             struct tty_struct *)'
   7  *     'int set_selection_kernel(struct tiocl_selection *, struct tty_struct *)'
   8  *     'void clear_selection(void)'
   9  *     'int paste_selection(struct tty_struct *)'
  10  *     'int sel_loadlut(u32 __user *)'
  11  *
  12  * Now that /dev/vcs exists, most of this can disappear again.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/tty.h>
  17 #include <linux/sched.h>
  18 #include <linux/mm.h>
  19 #include <linux/mutex.h>
  20 #include <linux/slab.h>
  21 #include <linux/types.h>
  22
  23 #include <linux/uaccess.h>
  24
  25 #include <linux/kbd_kern.h>
  26 #include <linux/vt_kern.h>
  27 #include <linux/consolemap.h>
  28 #include <linux/selection.h>
  29 #include <linux/tiocl.h>
  30 #include <linux/console.h>
  31 #include <linux/tty_flip.h>
  32
  33 #include <linux/sched/signal.h>
  34
  35 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
  36 #define is_space_on_vt(c)       ((c) == ' ')
  37
  38 /* FIXME: all this needs locking */
  39 static struct vc_selection {
  40         struct mutex lock;
  41         struct vc_data *cons;                   /* must not be deallocated */
  42         char *buffer;
  43         unsigned int buf_len;
  44         volatile int start;                     /* cleared by clear_selection */
  45         int end;
  46 } vc_sel = {
  47         .lock = __MUTEX_INITIALIZER(vc_sel.lock),
  48         .start = -1,
  49 };
  50
  51 /* clear_selection, highlight and highlight_pointer can be called
  52    from interrupt (via scrollback/front) */
  53
  54 /* set reverse video on characters s-e of console with selection. */
  55 static inline void highlight(const int s, const int e)
  56 {
  57         invert_screen(vc_sel.cons, s, e-s+2, true);
  58 }
  59
  60 /* use complementary color to show the pointer */
  61 static inline void highlight_pointer(const int where)
  62 {
  63         complement_pos(vc_sel.cons, where);
  64 }
  65
  66 static u32
  67 sel_pos(int n, bool unicode)
  68 {
  69         if (unicode)
  70                 return screen_glyph_unicode(vc_sel.cons, n / 2);
  71         return inverse_translate(vc_sel.cons, screen_glyph(vc_sel.cons, n),
  72                         false);
  73 }
  74
  75 /**
  76  * clear_selection - remove current selection
  77  *
  78  * Remove the current selection highlight, if any from the console holding the
  79  * selection.
  80  *
  81  * Locking: The caller must hold the console lock.
  82  */
  83 void clear_selection(void)
  84 {
  85         highlight_pointer(-1); /* hide the pointer */
  86         if (vc_sel.start != -1) {
  87                 highlight(vc_sel.start, vc_sel.end);
  88                 vc_sel.start = -1;
  89         }
  90 }
  91 EXPORT_SYMBOL_GPL(clear_selection);
  92
  93 bool vc_is_sel(const struct vc_data *vc)
  94 {
  95         return vc == vc_sel.cons;
  96 }
  97
  98 /*
  99  * User settable table: what characters are to be considered alphabetic?
 100  * 128 bits. Locked by the console lock.
 101  */
 102 static u32 inwordLut[]={
 103   0x00000000, /* control chars     */
 104   0x03FFE000, /* digits and "-./"  */
 105   0x87FFFFFE, /* uppercase and '_' */
 106   0x07FFFFFE, /* lowercase         */
 107 };
 108
 109 static inline int inword(const u32 c)
 110 {
 111         return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
 112 }
 113
 114 /**
 115  * sel_loadlut() - load the LUT table
 116  * @lut: user table
 117  *
 118  * Load the LUT table from user space. Make a temporary copy so a partial
 119  * update doesn't make a mess.
 120  *
 121  * Locking: The console lock is acquired.
 122  */
 123 int sel_loadlut(u32 __user *lut)
 124 {
 125         u32 tmplut[ARRAY_SIZE(inwordLut)];
 126
 127         if (copy_from_user(tmplut, lut, sizeof(inwordLut)))
 128                 return -EFAULT;
 129
 130         console_lock();
 131         memcpy(inwordLut, tmplut, sizeof(inwordLut));
 132         console_unlock();
 133
 134         return 0;
 135 }
 136
 137 /* does screen address p correspond to character at LH/RH edge of screen? */
 138 static inline int atedge(const int p, int size_row)
 139 {
 140         return (!(p % size_row) || !((p + 2) % size_row));
 141 }
 142
 143 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
 144 static int store_utf8(u32 c, char *p)
 145 {
 146         if (c < 0x80) {
 147                 /*  0******* */
 148                 p[0] = c;
 149                 return 1;
 150         } else if (c < 0x800) {
 151                 /* 110***** 10****** */
 152                 p[0] = 0xc0 | (c >> 6);
 153                 p[1] = 0x80 | (c & 0x3f);
 154                 return 2;
 155         } else if (c < 0x10000) {
 156                 /* 1110**** 10****** 10****** */
 157                 p[0] = 0xe0 | (c >> 12);
 158                 p[1] = 0x80 | ((c >> 6) & 0x3f);
 159                 p[2] = 0x80 | (c & 0x3f);
 160                 return 3;
 161         } else if (c < 0x110000) {
 162                 /* 11110*** 10****** 10****** 10****** */
 163                 p[0] = 0xf0 | (c >> 18);
 164                 p[1] = 0x80 | ((c >> 12) & 0x3f);
 165                 p[2] = 0x80 | ((c >> 6) & 0x3f);
 166                 p[3] = 0x80 | (c & 0x3f);
 167                 return 4;
 168         } else {
 169                 /* outside Unicode, replace with U+FFFD */
 170                 p[0] = 0xef;
 171                 p[1] = 0xbf;
 172                 p[2] = 0xbd;
 173                 return 3;
 174         }
 175 }
 176
 177 /**
 178  * set_selection_user - set the current selection.
 179  * @sel: user selection info
 180  * @tty: the console tty
 181  *
 182  * Invoked by the ioctl handle for the vt layer.
 183  *
 184  * Locking: The entire selection process is managed under the console_lock.
 185  * It's a lot under the lock but its hardly a performance path.
 186  */
 187 int set_selection_user(const struct tiocl_selection __user *sel,
 188                        struct tty_struct *tty)
 189 {
 190         struct tiocl_selection v;
 191
 192         if (copy_from_user(&v, sel, sizeof(*sel)))
 193                 return -EFAULT;
 194
 195         return set_selection_kernel(&v, tty);
 196 }
 197
 198 static int vc_selection_store_chars(struct vc_data *vc, bool unicode)
 199 {
 200         char *bp, *obp;
 201         unsigned int i;
 202
 203         /* Allocate a new buffer before freeing the old one ... */
 204         /* chars can take up to 4 bytes with unicode */
 205         bp = kmalloc_array((vc_sel.end - vc_sel.start) / 2 + 1, unicode ? 4 : 1,
 206                            GFP_KERNEL | __GFP_NOWARN);
 207         if (!bp) {
 208                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 209                 clear_selection();
 210                 return -ENOMEM;
 211         }
 212         kfree(vc_sel.buffer);
 213         vc_sel.buffer = bp;
 214
 215         obp = bp;
 216         for (i = vc_sel.start; i <= vc_sel.end; i += 2) {
 217                 u32 c = sel_pos(i, unicode);
 218                 if (unicode)
 219                         bp += store_utf8(c, bp);
 220                 else
 221                         *bp++ = c;
 222                 if (!is_space_on_vt(c))
 223                         obp = bp;
 224                 if (!((i + 2) % vc->vc_size_row)) {
 225                         /* strip trailing blanks from line and add newline,
 226                            unless non-space at end of line. */
 227                         if (obp != bp) {
 228                                 bp = obp;
 229                                 *bp++ = '\r';
 230                         }
 231                         obp = bp;
 232                 }
 233         }
 234         vc_sel.buf_len = bp - vc_sel.buffer;
 235
 236         return 0;
 237 }
 238
 239 static int vc_do_selection(struct vc_data *vc, unsigned short mode, int ps,
 240                 int pe)
 241 {
 242         int new_sel_start, new_sel_end, spc;
 243         bool unicode = vt_do_kdgkbmode(fg_console) == K_UNICODE;
 244
 245         switch (mode) {
 246         case TIOCL_SELCHAR:     /* character-by-character selection */
 247                 new_sel_start = ps;
 248                 new_sel_end = pe;
 249                 break;
 250         case TIOCL_SELWORD:     /* word-by-word selection */
 251                 spc = is_space_on_vt(sel_pos(ps, unicode));
 252                 for (new_sel_start = ps; ; ps -= 2) {
 253                         if ((spc && !is_space_on_vt(sel_pos(ps, unicode))) ||
 254                             (!spc && !inword(sel_pos(ps, unicode))))
 255                                 break;
 256                         new_sel_start = ps;
 257                         if (!(ps % vc->vc_size_row))
 258                                 break;
 259                 }
 260
 261                 spc = is_space_on_vt(sel_pos(pe, unicode));
 262                 for (new_sel_end = pe; ; pe += 2) {
 263                         if ((spc && !is_space_on_vt(sel_pos(pe, unicode))) ||
 264                             (!spc && !inword(sel_pos(pe, unicode))))
 265                                 break;
 266                         new_sel_end = pe;
 267                         if (!((pe + 2) % vc->vc_size_row))
 268                                 break;
 269                 }
 270                 break;
 271         case TIOCL_SELLINE:     /* line-by-line selection */
 272                 new_sel_start = rounddown(ps, vc->vc_size_row);
 273                 new_sel_end = rounddown(pe, vc->vc_size_row) +
 274                         vc->vc_size_row - 2;
 275                 break;
 276         case TIOCL_SELPOINTER:
 277                 highlight_pointer(pe);
 278                 return 0;
 279         default:
 280                 return -EINVAL;
 281         }
 282
 283         /* remove the pointer */
 284         highlight_pointer(-1);
 285
 286         /* select to end of line if on trailing space */
 287         if (new_sel_end > new_sel_start &&
 288                 !atedge(new_sel_end, vc->vc_size_row) &&
 289                 is_space_on_vt(sel_pos(new_sel_end, unicode))) {
 290                 for (pe = new_sel_end + 2; ; pe += 2)
 291                         if (!is_space_on_vt(sel_pos(pe, unicode)) ||
 292                             atedge(pe, vc->vc_size_row))
 293                                 break;
 294                 if (is_space_on_vt(sel_pos(pe, unicode)))
 295                         new_sel_end = pe;
 296         }
 297         if (vc_sel.start == -1) /* no current selection */
 298                 highlight(new_sel_start, new_sel_end);
 299         else if (new_sel_start == vc_sel.start)
 300         {
 301                 if (new_sel_end == vc_sel.end)  /* no action required */
 302                         return 0;
 303                 else if (new_sel_end > vc_sel.end)      /* extend to right */
 304                         highlight(vc_sel.end + 2, new_sel_end);
 305                 else                            /* contract from right */
 306                         highlight(new_sel_end + 2, vc_sel.end);
 307         }
 308         else if (new_sel_end == vc_sel.end)
 309         {
 310                 if (new_sel_start < vc_sel.start) /* extend to left */
 311                         highlight(new_sel_start, vc_sel.start - 2);
 312                 else                            /* contract from left */
 313                         highlight(vc_sel.start, new_sel_start - 2);
 314         }
 315         else    /* some other case; start selection from scratch */
 316         {
 317                 clear_selection();
 318                 highlight(new_sel_start, new_sel_end);
 319         }
 320         vc_sel.start = new_sel_start;
 321         vc_sel.end = new_sel_end;
 322
 323         return vc_selection_store_chars(vc, unicode);
 324 }
 325
 326 static int vc_selection(struct vc_data *vc, struct tiocl_selection *v,
 327                 struct tty_struct *tty)
 328 {
 329         int ps, pe;
 330
 331         poke_blanked_console();
 332
 333         if (v->sel_mode == TIOCL_SELCLEAR) {
 334                 /* useful for screendump without selection highlights */
 335                 clear_selection();
 336                 return 0;
 337         }
 338
 339         v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
 340         v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
 341         v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
 342         v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
 343
 344         if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
 345                 mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
 346                              v->ys);
 347                 return 0;
 348         }
 349
 350         ps = v->ys * vc->vc_size_row + (v->xs << 1);
 351         pe = v->ye * vc->vc_size_row + (v->xe << 1);
 352         if (ps > pe)    /* make vc_sel.start <= vc_sel.end */
 353                 swap(ps, pe);
 354
 355         if (vc_sel.cons != vc) {
 356                 clear_selection();
 357                 vc_sel.cons = vc;
 358         }
 359
 360         return vc_do_selection(vc, v->sel_mode, ps, pe);
 361 }
 362
 363 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
 364 {
 365         int ret;
 366
 367         mutex_lock(&vc_sel.lock);
 368         console_lock();
 369         ret = vc_selection(vc_cons[fg_console].d, v, tty);
 370         console_unlock();
 371         mutex_unlock(&vc_sel.lock);
 372
 373         return ret;
 374 }
 375 EXPORT_SYMBOL_GPL(set_selection_kernel);
 376
 377 /* Insert the contents of the selection buffer into the
 378  * queue of the tty associated with the current console.
 379  * Invoked by ioctl().
 380  *
 381  * Locking: called without locks. Calls the ldisc wrongly with
 382  * unsafe methods,
 383  */
 384 int paste_selection(struct tty_struct *tty)
 385 {
 386         struct vc_data *vc = tty->driver_data;
 387         int     pasted = 0;
 388         size_t count;
 389         struct  tty_ldisc *ld;
 390         DECLARE_WAITQUEUE(wait, current);
 391         int ret = 0;
 392
 393         console_lock();
 394         poke_blanked_console();
 395         console_unlock();
 396
 397         ld = tty_ldisc_ref_wait(tty);
 398         if (!ld)
 399                 return -EIO;    /* ldisc was hung up */
 400         tty_buffer_lock_exclusive(&vc->port);
 401
 402         add_wait_queue(&vc->paste_wait, &wait);
 403         mutex_lock(&vc_sel.lock);
 404         while (vc_sel.buffer && vc_sel.buf_len > pasted) {
 405                 set_current_state(TASK_INTERRUPTIBLE);
 406                 if (signal_pending(current)) {
 407                         ret = -EINTR;
 408                         break;
 409                 }
 410                 if (tty_throttled(tty)) {
 411                         mutex_unlock(&vc_sel.lock);
 412                         schedule();
 413                         mutex_lock(&vc_sel.lock);
 414                         continue;
 415                 }
 416                 __set_current_state(TASK_RUNNING);
 417                 count = vc_sel.buf_len - pasted;
 418                 count = tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL,
 419                                               count);
 420                 pasted += count;
 421         }
 422         mutex_unlock(&vc_sel.lock);
 423         remove_wait_queue(&vc->paste_wait, &wait);
 424         __set_current_state(TASK_RUNNING);
 425
 426         tty_buffer_unlock_exclusive(&vc->port);
 427         tty_ldisc_deref(ld);
 428         return ret;
 429 }
 430 EXPORT_SYMBOL_GPL(paste_selection);