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