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