drivers/tty/vt/selection.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This module exports the functions:
   4  *
   5  *     'int set_selection(struct tiocl_selection __user *, struct tty_struct *)'
   6  *     'void clear_selection(void)'
   7  *     'int paste_selection(struct tty_struct *)'
   8  *     'int sel_loadlut(char __user *)'
   9  *
  10  * Now that /dev/vcs exists, most of this can disappear again.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/tty.h>
  15 #include <linux/sched.h>
  16 #include <linux/mm.h>
  17 #include <linux/slab.h>
  18 #include <linux/types.h>
  19
  20 #include <linux/uaccess.h>
  21
  22 #include <linux/kbd_kern.h>
  23 #include <linux/vt_kern.h>
  24 #include <linux/consolemap.h>
  25 #include <linux/selection.h>
  26 #include <linux/tiocl.h>
  27 #include <linux/console.h>
  28 #include <linux/tty_flip.h>
  29
  30 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
  31 #define isspace(c)      ((c) == ' ')
  32
  33 extern void poke_blanked_console(void);
  34
  35 /* FIXME: all this needs locking */
  36 /* Variables for selection control. */
  37 /* Use a dynamic buffer, instead of static (Dec 1994) */
  38 struct vc_data *sel_cons;               /* must not be deallocated */
  39 static int use_unicode;
  40 static volatile int sel_start = -1;     /* cleared by clear_selection */
  41 static int sel_end;
  42 static int sel_buffer_lth;
  43 static char *sel_buffer;
  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 static inline void highlight(const int s, const int e)
  50 {
  51         invert_screen(sel_cons, s, e-s+2, 1);
  52 }
  53
  54 /* use complementary color to show the pointer */
  55 static inline void highlight_pointer(const int where)
  56 {
  57         complement_pos(sel_cons, where);
  58 }
  59
  60 static u16
  61 sel_pos(int n)
  62 {
  63         return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
  64                                 use_unicode);
  65 }
  66
  67 /**
  68  *      clear_selection         -       remove current selection
  69  *
  70  *      Remove the current selection highlight, if any from the console
  71  *      holding the selection. The caller must hold the console lock.
  72  */
  73 void clear_selection(void)
  74 {
  75         highlight_pointer(-1); /* hide the pointer */
  76         if (sel_start != -1) {
  77                 highlight(sel_start, sel_end);
  78                 sel_start = -1;
  79         }
  80 }
  81
  82 /*
  83  * User settable table: what characters are to be considered alphabetic?
  84  * 128 bits. Locked by the console lock.
  85  */
  86 static u32 inwordLut[]={
  87   0x00000000, /* control chars     */
  88   0x03FFE000, /* digits and "-./"  */
  89   0x87FFFFFE, /* uppercase and '_' */
  90   0x07FFFFFE, /* lowercase         */
  91 };
  92
  93 static inline int inword(const u16 c) {
  94         return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
  95 }
  96
  97 /**
  98  *      set loadlut             -       load the LUT table
  99  *      @p: user table
 100  *
 101  *      Load the LUT table from user space. The caller must hold the console
 102  *      lock. Make a temporary copy so a partial update doesn't make a mess.
 103  */
 104 int sel_loadlut(char __user *p)
 105 {
 106         u32 tmplut[ARRAY_SIZE(inwordLut)];
 107         if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
 108                 return -EFAULT;
 109         memcpy(inwordLut, tmplut, sizeof(inwordLut));
 110         return 0;
 111 }
 112
 113 /* does screen address p correspond to character at LH/RH edge of screen? */
 114 static inline int atedge(const int p, int size_row)
 115 {
 116         return (!(p % size_row) || !((p + 2) % size_row));
 117 }
 118
 119 /* constrain v such that v <= u */
 120 static inline unsigned short limit(const unsigned short v, const unsigned short u)
 121 {
 122         return (v > u) ? u : v;
 123 }
 124
 125 /* stores the char in UTF8 and returns the number of bytes used (1-3) */
 126 static int store_utf8(u16 c, char *p)
 127 {
 128         if (c < 0x80) {
 129                 /*  0******* */
 130                 p[0] = c;
 131                 return 1;
 132         } else if (c < 0x800) {
 133                 /* 110***** 10****** */
 134                 p[0] = 0xc0 | (c >> 6);
 135                 p[1] = 0x80 | (c & 0x3f);
 136                 return 2;
 137         } else {
 138                 /* 1110**** 10****** 10****** */
 139                 p[0] = 0xe0 | (c >> 12);
 140                 p[1] = 0x80 | ((c >> 6) & 0x3f);
 141                 p[2] = 0x80 | (c & 0x3f);
 142                 return 3;
 143         }
 144 }
 145
 146 /**
 147  *      set_selection           -       set the current selection.
 148  *      @sel: user selection info
 149  *      @tty: the console tty
 150  *
 151  *      Invoked by the ioctl handle for the vt layer.
 152  *
 153  *      The entire selection process is managed under the console_lock. It's
 154  *       a lot under the lock but its hardly a performance path
 155  */
 156 int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
 157 {
 158         struct vc_data *vc = vc_cons[fg_console].d;
 159         int sel_mode, new_sel_start, new_sel_end, spc;
 160         char *bp, *obp;
 161         int i, ps, pe, multiplier;
 162         u16 c;
 163         int mode;
 164
 165         poke_blanked_console();
 166
 167         { unsigned short xs, ys, xe, ye;
 168
 169           if (!access_ok(VERIFY_READ, sel, sizeof(*sel)))
 170                 return -EFAULT;
 171           __get_user(xs, &sel->xs);
 172           __get_user(ys, &sel->ys);
 173           __get_user(xe, &sel->xe);
 174           __get_user(ye, &sel->ye);
 175           __get_user(sel_mode, &sel->sel_mode);
 176           xs--; ys--; xe--; ye--;
 177           xs = limit(xs, vc->vc_cols - 1);
 178           ys = limit(ys, vc->vc_rows - 1);
 179           xe = limit(xe, vc->vc_cols - 1);
 180           ye = limit(ye, vc->vc_rows - 1);
 181           ps = ys * vc->vc_size_row + (xs << 1);
 182           pe = ye * vc->vc_size_row + (xe << 1);
 183
 184           if (sel_mode == TIOCL_SELCLEAR) {
 185               /* useful for screendump without selection highlights */
 186               clear_selection();
 187               return 0;
 188           }
 189
 190           if (mouse_reporting() && (sel_mode & TIOCL_SELMOUSEREPORT)) {
 191               mouse_report(tty, sel_mode & TIOCL_SELBUTTONMASK, xs, ys);
 192               return 0;
 193           }
 194         }
 195
 196         if (ps > pe)    /* make sel_start <= sel_end */
 197         {
 198                 int tmp = ps;
 199                 ps = pe;
 200                 pe = tmp;
 201         }
 202
 203         if (sel_cons != vc_cons[fg_console].d) {
 204                 clear_selection();
 205                 sel_cons = vc_cons[fg_console].d;
 206         }
 207         mode = vt_do_kdgkbmode(fg_console);
 208         if (mode == K_UNICODE)
 209                 use_unicode = 1;
 210         else
 211                 use_unicode = 0;
 212
 213         switch (sel_mode)
 214         {
 215                 case TIOCL_SELCHAR:     /* character-by-character selection */
 216                         new_sel_start = ps;
 217                         new_sel_end = pe;
 218                         break;
 219                 case TIOCL_SELWORD:     /* word-by-word selection */
 220                         spc = isspace(sel_pos(ps));
 221                         for (new_sel_start = ps; ; ps -= 2)
 222                         {
 223                                 if ((spc && !isspace(sel_pos(ps))) ||
 224                                     (!spc && !inword(sel_pos(ps))))
 225                                         break;
 226                                 new_sel_start = ps;
 227                                 if (!(ps % vc->vc_size_row))
 228                                         break;
 229                         }
 230                         spc = isspace(sel_pos(pe));
 231                         for (new_sel_end = pe; ; pe += 2)
 232                         {
 233                                 if ((spc && !isspace(sel_pos(pe))) ||
 234                                     (!spc && !inword(sel_pos(pe))))
 235                                         break;
 236                                 new_sel_end = pe;
 237                                 if (!((pe + 2) % vc->vc_size_row))
 238                                         break;
 239                         }
 240                         break;
 241                 case TIOCL_SELLINE:     /* line-by-line selection */
 242                         new_sel_start = ps - ps % vc->vc_size_row;
 243                         new_sel_end = pe + vc->vc_size_row
 244                                     - pe % vc->vc_size_row - 2;
 245                         break;
 246                 case TIOCL_SELPOINTER:
 247                         highlight_pointer(pe);
 248                         return 0;
 249                 default:
 250                         return -EINVAL;
 251         }
 252
 253         /* remove the pointer */
 254         highlight_pointer(-1);
 255
 256         /* select to end of line if on trailing space */
 257         if (new_sel_end > new_sel_start &&
 258                 !atedge(new_sel_end, vc->vc_size_row) &&
 259                 isspace(sel_pos(new_sel_end))) {
 260                 for (pe = new_sel_end + 2; ; pe += 2)
 261                         if (!isspace(sel_pos(pe)) ||
 262                             atedge(pe, vc->vc_size_row))
 263                                 break;
 264                 if (isspace(sel_pos(pe)))
 265                         new_sel_end = pe;
 266         }
 267         if (sel_start == -1)    /* no current selection */
 268                 highlight(new_sel_start, new_sel_end);
 269         else if (new_sel_start == sel_start)
 270         {
 271                 if (new_sel_end == sel_end)     /* no action required */
 272                         return 0;
 273                 else if (new_sel_end > sel_end) /* extend to right */
 274                         highlight(sel_end + 2, new_sel_end);
 275                 else                            /* contract from right */
 276                         highlight(new_sel_end + 2, sel_end);
 277         }
 278         else if (new_sel_end == sel_end)
 279         {
 280                 if (new_sel_start < sel_start)  /* extend to left */
 281                         highlight(new_sel_start, sel_start - 2);
 282                 else                            /* contract from left */
 283                         highlight(sel_start, new_sel_start - 2);
 284         }
 285         else    /* some other case; start selection from scratch */
 286         {
 287                 clear_selection();
 288                 highlight(new_sel_start, new_sel_end);
 289         }
 290         sel_start = new_sel_start;
 291         sel_end = new_sel_end;
 292
 293         /* Allocate a new buffer before freeing the old one ... */
 294         multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
 295         bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
 296         if (!bp) {
 297                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 298                 clear_selection();
 299                 return -ENOMEM;
 300         }
 301         kfree(sel_buffer);
 302         sel_buffer = bp;
 303
 304         obp = bp;
 305         for (i = sel_start; i <= sel_end; i += 2) {
 306                 c = sel_pos(i);
 307                 if (use_unicode)
 308                         bp += store_utf8(c, bp);
 309                 else
 310                         *bp++ = c;
 311                 if (!isspace(c))
 312                         obp = bp;
 313                 if (! ((i + 2) % vc->vc_size_row)) {
 314                         /* strip trailing blanks from line and add newline,
 315                            unless non-space at end of line. */
 316                         if (obp != bp) {
 317                                 bp = obp;
 318                                 *bp++ = '\r';
 319                         }
 320                         obp = bp;
 321                 }
 322         }
 323         sel_buffer_lth = bp - sel_buffer;
 324         return 0;
 325 }
 326
 327 /* Insert the contents of the selection buffer into the
 328  * queue of the tty associated with the current console.
 329  * Invoked by ioctl().
 330  *
 331  * Locking: called without locks. Calls the ldisc wrongly with
 332  * unsafe methods,
 333  */
 334 int paste_selection(struct tty_struct *tty)
 335 {
 336         struct vc_data *vc = tty->driver_data;
 337         int     pasted = 0;
 338         unsigned int count;
 339         struct  tty_ldisc *ld;
 340         DECLARE_WAITQUEUE(wait, current);
 341
 342         console_lock();
 343         poke_blanked_console();
 344         console_unlock();
 345
 346         ld = tty_ldisc_ref_wait(tty);
 347         if (!ld)
 348                 return -EIO;    /* ldisc was hung up */
 349         tty_buffer_lock_exclusive(&vc->port);
 350
 351         add_wait_queue(&vc->paste_wait, &wait);
 352         while (sel_buffer && sel_buffer_lth > pasted) {
 353                 set_current_state(TASK_INTERRUPTIBLE);
 354                 if (tty_throttled(tty)) {
 355                         schedule();
 356                         continue;
 357                 }
 358                 __set_current_state(TASK_RUNNING);
 359                 count = sel_buffer_lth - pasted;
 360                 count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 361                                               count);
 362                 pasted += count;
 363         }
 364         remove_wait_queue(&vc->paste_wait, &wait);
 365         __set_current_state(TASK_RUNNING);
 366
 367         tty_buffer_unlock_exclusive(&vc->port);
 368         tty_ldisc_deref(ld);
 369         return 0;
 370 }