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 extern void poke_blanked_console(void);
  39
  40 /* FIXME: all this needs locking */
  41 /* Variables for selection control. */
  42 /* Use a dynamic buffer, instead of static (Dec 1994) */
  43 struct vc_data *sel_cons;               /* must not be deallocated */
  44 static int use_unicode;
  45 static volatile int sel_start = -1;     /* cleared by clear_selection */
  46 static int sel_end;
  47 static int sel_buffer_lth;
  48 static char *sel_buffer;
  49 static DEFINE_MUTEX(sel_lock);
  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(sel_cons, s, e-s+2, 1);
  58 }
  59
  60 /* use complementary color to show the pointer */
  61 static inline void highlight_pointer(const int where)
  62 {
  63         complement_pos(sel_cons, where);
  64 }
  65
  66 static u32
  67 sel_pos(int n)
  68 {
  69         if (use_unicode)
  70                 return screen_glyph_unicode(sel_cons, n / 2);
  71         return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
  72                                 0);
  73 }
  74
  75 /**
  76  *      clear_selection         -       remove current selection
  77  *
  78  *      Remove the current selection highlight, if any from the console
  79  *      holding the selection. The caller must hold the console lock.
  80  */
  81 void clear_selection(void)
  82 {
  83         highlight_pointer(-1); /* hide the pointer */
  84         if (sel_start != -1) {
  85                 highlight(sel_start, sel_end);
  86                 sel_start = -1;
  87         }
  88 }
  89 EXPORT_SYMBOL_GPL(clear_selection);
  90
  91 /*
  92  * User settable table: what characters are to be considered alphabetic?
  93  * 128 bits. Locked by the console lock.
  94  */
  95 static u32 inwordLut[]={
  96   0x00000000, /* control chars     */
  97   0x03FFE000, /* digits and "-./"  */
  98   0x87FFFFFE, /* uppercase and '_' */
  99   0x07FFFFFE, /* lowercase         */
 100 };
 101
 102 static inline int inword(const u32 c)
 103 {
 104         return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
 105 }
 106
 107 /**
 108  *      set loadlut             -       load the LUT table
 109  *      @p: user table
 110  *
 111  *      Load the LUT table from user space. The caller must hold the console
 112  *      lock. Make a temporary copy so a partial update doesn't make a mess.
 113  */
 114 int sel_loadlut(char __user *p)
 115 {
 116         u32 tmplut[ARRAY_SIZE(inwordLut)];
 117         if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
 118                 return -EFAULT;
 119         memcpy(inwordLut, tmplut, sizeof(inwordLut));
 120         return 0;
 121 }
 122
 123 /* does screen address p correspond to character at LH/RH edge of screen? */
 124 static inline int atedge(const int p, int size_row)
 125 {
 126         return (!(p % size_row) || !((p + 2) % size_row));
 127 }
 128
 129 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
 130 static int store_utf8(u32 c, char *p)
 131 {
 132         if (c < 0x80) {
 133                 /*  0******* */
 134                 p[0] = c;
 135                 return 1;
 136         } else if (c < 0x800) {
 137                 /* 110***** 10****** */
 138                 p[0] = 0xc0 | (c >> 6);
 139                 p[1] = 0x80 | (c & 0x3f);
 140                 return 2;
 141         } else if (c < 0x10000) {
 142                 /* 1110**** 10****** 10****** */
 143                 p[0] = 0xe0 | (c >> 12);
 144                 p[1] = 0x80 | ((c >> 6) & 0x3f);
 145                 p[2] = 0x80 | (c & 0x3f);
 146                 return 3;
 147         } else if (c < 0x110000) {
 148                 /* 11110*** 10****** 10****** 10****** */
 149                 p[0] = 0xf0 | (c >> 18);
 150                 p[1] = 0x80 | ((c >> 12) & 0x3f);
 151                 p[2] = 0x80 | ((c >> 6) & 0x3f);
 152                 p[3] = 0x80 | (c & 0x3f);
 153                 return 4;
 154         } else {
 155                 /* outside Unicode, replace with U+FFFD */
 156                 p[0] = 0xef;
 157                 p[1] = 0xbf;
 158                 p[2] = 0xbd;
 159                 return 3;
 160         }
 161 }
 162
 163 /**
 164  *      set_selection_user      -       set the current selection.
 165  *      @sel: user selection info
 166  *      @tty: the console tty
 167  *
 168  *      Invoked by the ioctl handle for the vt layer.
 169  *
 170  *      The entire selection process is managed under the console_lock. It's
 171  *       a lot under the lock but its hardly a performance path
 172  */
 173 int set_selection_user(const struct tiocl_selection __user *sel,
 174                        struct tty_struct *tty)
 175 {
 176         struct tiocl_selection v;
 177
 178         if (copy_from_user(&v, sel, sizeof(*sel)))
 179                 return -EFAULT;
 180
 181         return set_selection_kernel(&v, tty);
 182 }
 183
 184 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
 185 {
 186         struct vc_data *vc = vc_cons[fg_console].d;
 187         int new_sel_start, new_sel_end, spc;
 188         char *bp, *obp;
 189         int i, ps, pe, multiplier;
 190         u32 c;
 191         int mode, ret = 0;
 192
 193         poke_blanked_console();
 194
 195         v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
 196         v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
 197         v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
 198         v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
 199         ps = v->ys * vc->vc_size_row + (v->xs << 1);
 200         pe = v->ye * vc->vc_size_row + (v->xe << 1);
 201
 202         if (v->sel_mode == TIOCL_SELCLEAR) {
 203                 /* useful for screendump without selection highlights */
 204                 clear_selection();
 205                 return 0;
 206         }
 207
 208         if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
 209                 mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
 210                              v->ys);
 211                 return 0;
 212         }
 213
 214         if (ps > pe)    /* make sel_start <= sel_end */
 215                 swap(ps, pe);
 216
 217         mutex_lock(&sel_lock);
 218         if (sel_cons != vc_cons[fg_console].d) {
 219                 clear_selection();
 220                 sel_cons = vc_cons[fg_console].d;
 221         }
 222         mode = vt_do_kdgkbmode(fg_console);
 223         if (mode == K_UNICODE)
 224                 use_unicode = 1;
 225         else
 226                 use_unicode = 0;
 227
 228         switch (v->sel_mode)
 229         {
 230                 case TIOCL_SELCHAR:     /* character-by-character selection */
 231                         new_sel_start = ps;
 232                         new_sel_end = pe;
 233                         break;
 234                 case TIOCL_SELWORD:     /* word-by-word selection */
 235                         spc = isspace(sel_pos(ps));
 236                         for (new_sel_start = ps; ; ps -= 2)
 237                         {
 238                                 if ((spc && !isspace(sel_pos(ps))) ||
 239                                     (!spc && !inword(sel_pos(ps))))
 240                                         break;
 241                                 new_sel_start = ps;
 242                                 if (!(ps % vc->vc_size_row))
 243                                         break;
 244                         }
 245                         spc = isspace(sel_pos(pe));
 246                         for (new_sel_end = pe; ; pe += 2)
 247                         {
 248                                 if ((spc && !isspace(sel_pos(pe))) ||
 249                                     (!spc && !inword(sel_pos(pe))))
 250                                         break;
 251                                 new_sel_end = pe;
 252                                 if (!((pe + 2) % vc->vc_size_row))
 253                                         break;
 254                         }
 255                         break;
 256                 case TIOCL_SELLINE:     /* line-by-line selection */
 257                         new_sel_start = ps - ps % vc->vc_size_row;
 258                         new_sel_end = pe + vc->vc_size_row
 259                                     - pe % vc->vc_size_row - 2;
 260                         break;
 261                 case TIOCL_SELPOINTER:
 262                         highlight_pointer(pe);
 263                         goto unlock;
 264                 default:
 265                         ret = -EINVAL;
 266                         goto unlock;
 267         }
 268
 269         /* remove the pointer */
 270         highlight_pointer(-1);
 271
 272         /* select to end of line if on trailing space */
 273         if (new_sel_end > new_sel_start &&
 274                 !atedge(new_sel_end, vc->vc_size_row) &&
 275                 isspace(sel_pos(new_sel_end))) {
 276                 for (pe = new_sel_end + 2; ; pe += 2)
 277                         if (!isspace(sel_pos(pe)) ||
 278                             atedge(pe, vc->vc_size_row))
 279                                 break;
 280                 if (isspace(sel_pos(pe)))
 281                         new_sel_end = pe;
 282         }
 283         if (sel_start == -1)    /* no current selection */
 284                 highlight(new_sel_start, new_sel_end);
 285         else if (new_sel_start == sel_start)
 286         {
 287                 if (new_sel_end == sel_end)     /* no action required */
 288                         goto unlock;
 289                 else if (new_sel_end > sel_end) /* extend to right */
 290                         highlight(sel_end + 2, new_sel_end);
 291                 else                            /* contract from right */
 292                         highlight(new_sel_end + 2, sel_end);
 293         }
 294         else if (new_sel_end == sel_end)
 295         {
 296                 if (new_sel_start < sel_start)  /* extend to left */
 297                         highlight(new_sel_start, sel_start - 2);
 298                 else                            /* contract from left */
 299                         highlight(sel_start, new_sel_start - 2);
 300         }
 301         else    /* some other case; start selection from scratch */
 302         {
 303                 clear_selection();
 304                 highlight(new_sel_start, new_sel_end);
 305         }
 306         sel_start = new_sel_start;
 307         sel_end = new_sel_end;
 308
 309         /* Allocate a new buffer before freeing the old one ... */
 310         multiplier = use_unicode ? 4 : 1;  /* chars can take up to 4 bytes */
 311         bp = kmalloc_array((sel_end - sel_start) / 2 + 1, multiplier,
 312                            GFP_KERNEL);
 313         if (!bp) {
 314                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 315                 clear_selection();
 316                 ret = -ENOMEM;
 317                 goto unlock;
 318         }
 319         kfree(sel_buffer);
 320         sel_buffer = bp;
 321
 322         obp = bp;
 323         for (i = sel_start; i <= sel_end; i += 2) {
 324                 c = sel_pos(i);
 325                 if (use_unicode)
 326                         bp += store_utf8(c, bp);
 327                 else
 328                         *bp++ = c;
 329                 if (!isspace(c))
 330                         obp = bp;
 331                 if (! ((i + 2) % vc->vc_size_row)) {
 332                         /* strip trailing blanks from line and add newline,
 333                            unless non-space at end of line. */
 334                         if (obp != bp) {
 335                                 bp = obp;
 336                                 *bp++ = '\r';
 337                         }
 338                         obp = bp;
 339                 }
 340         }
 341         sel_buffer_lth = bp - sel_buffer;
 342 unlock:
 343         mutex_unlock(&sel_lock);
 344         return ret;
 345 }
 346 EXPORT_SYMBOL_GPL(set_selection_kernel);
 347
 348 /* Insert the contents of the selection buffer into the
 349  * queue of the tty associated with the current console.
 350  * Invoked by ioctl().
 351  *
 352  * Locking: called without locks. Calls the ldisc wrongly with
 353  * unsafe methods,
 354  */
 355 int paste_selection(struct tty_struct *tty)
 356 {
 357         struct vc_data *vc = tty->driver_data;
 358         int     pasted = 0;
 359         unsigned int count;
 360         struct  tty_ldisc *ld;
 361         DECLARE_WAITQUEUE(wait, current);
 362         int ret = 0;
 363
 364         console_lock();
 365         poke_blanked_console();
 366         console_unlock();
 367
 368         ld = tty_ldisc_ref_wait(tty);
 369         if (!ld)
 370                 return -EIO;    /* ldisc was hung up */
 371         tty_buffer_lock_exclusive(&vc->port);
 372
 373         add_wait_queue(&vc->paste_wait, &wait);
 374         mutex_lock(&sel_lock);
 375         while (sel_buffer && sel_buffer_lth > pasted) {
 376                 set_current_state(TASK_INTERRUPTIBLE);
 377                 if (signal_pending(current)) {
 378                         ret = -EINTR;
 379                         break;
 380                 }
 381                 if (tty_throttled(tty)) {
 382                         mutex_unlock(&sel_lock);
 383                         schedule();
 384                         mutex_lock(&sel_lock);
 385                         continue;
 386                 }
 387                 __set_current_state(TASK_RUNNING);
 388                 count = sel_buffer_lth - pasted;
 389                 count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 390                                               count);
 391                 pasted += count;
 392         }
 393         mutex_unlock(&sel_lock);
 394         remove_wait_queue(&vc->paste_wait, &wait);
 395         __set_current_state(TASK_RUNNING);
 396
 397         tty_buffer_unlock_exclusive(&vc->port);
 398         tty_ldisc_deref(ld);
 399         return ret;
 400 }
 401 EXPORT_SYMBOL_GPL(paste_selection);