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/slab.h>
  20 #include <linux/types.h>
  21
  22 #include <linux/uaccess.h>
  23
  24 #include <linux/kbd_kern.h>
  25 #include <linux/vt_kern.h>
  26 #include <linux/consolemap.h>
  27 #include <linux/selection.h>
  28 #include <linux/tiocl.h>
  29 #include <linux/console.h>
  30 #include <linux/tty_flip.h>
  31
  32 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
  33 #define isspace(c)      ((c) == ' ')
  34
  35 extern void poke_blanked_console(void);
  36
  37 /* FIXME: all this needs locking */
  38 /* Variables for selection control. */
  39 /* Use a dynamic buffer, instead of static (Dec 1994) */
  40 struct vc_data *sel_cons;               /* must not be deallocated */
  41 static int use_unicode;
  42 static volatile int sel_start = -1;     /* cleared by clear_selection */
  43 static int sel_end;
  44 static int sel_buffer_lth;
  45 static char *sel_buffer;
  46
  47 /* clear_selection, highlight and highlight_pointer can be called
  48    from interrupt (via scrollback/front) */
  49
  50 /* set reverse video on characters s-e of console with selection. */
  51 static inline void highlight(const int s, const int e)
  52 {
  53         invert_screen(sel_cons, s, e-s+2, 1);
  54 }
  55
  56 /* use complementary color to show the pointer */
  57 static inline void highlight_pointer(const int where)
  58 {
  59         complement_pos(sel_cons, where);
  60 }
  61
  62 static u32
  63 sel_pos(int n)
  64 {
  65         if (use_unicode)
  66                 return screen_glyph_unicode(sel_cons, n / 2);
  67         return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
  68                                 0);
  69 }
  70
  71 /**
  72  *      clear_selection         -       remove current selection
  73  *
  74  *      Remove the current selection highlight, if any from the console
  75  *      holding the selection. The caller must hold the console lock.
  76  */
  77 void clear_selection(void)
  78 {
  79         highlight_pointer(-1); /* hide the pointer */
  80         if (sel_start != -1) {
  81                 highlight(sel_start, sel_end);
  82                 sel_start = -1;
  83         }
  84 }
  85 EXPORT_SYMBOL_GPL(clear_selection);
  86
  87 /*
  88  * User settable table: what characters are to be considered alphabetic?
  89  * 128 bits. Locked by the console lock.
  90  */
  91 static u32 inwordLut[]={
  92   0x00000000, /* control chars     */
  93   0x03FFE000, /* digits and "-./"  */
  94   0x87FFFFFE, /* uppercase and '_' */
  95   0x07FFFFFE, /* lowercase         */
  96 };
  97
  98 static inline int inword(const u32 c)
  99 {
 100         return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
 101 }
 102
 103 /**
 104  *      set loadlut             -       load the LUT table
 105  *      @p: user table
 106  *
 107  *      Load the LUT table from user space. The caller must hold the console
 108  *      lock. Make a temporary copy so a partial update doesn't make a mess.
 109  */
 110 int sel_loadlut(char __user *p)
 111 {
 112         u32 tmplut[ARRAY_SIZE(inwordLut)];
 113         if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
 114                 return -EFAULT;
 115         memcpy(inwordLut, tmplut, sizeof(inwordLut));
 116         return 0;
 117 }
 118
 119 /* does screen address p correspond to character at LH/RH edge of screen? */
 120 static inline int atedge(const int p, int size_row)
 121 {
 122         return (!(p % size_row) || !((p + 2) % size_row));
 123 }
 124
 125 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
 126 static int store_utf8(u32 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 if (c < 0x10000) {
 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         } else if (c < 0x110000) {
 144                 /* 11110*** 10****** 10****** 10****** */
 145                 p[0] = 0xf0 | (c >> 18);
 146                 p[1] = 0x80 | ((c >> 12) & 0x3f);
 147                 p[2] = 0x80 | ((c >> 6) & 0x3f);
 148                 p[3] = 0x80 | (c & 0x3f);
 149                 return 4;
 150         } else {
 151                 /* outside Unicode, replace with U+FFFD */
 152                 p[0] = 0xef;
 153                 p[1] = 0xbf;
 154                 p[2] = 0xbd;
 155                 return 3;
 156         }
 157 }
 158
 159 /**
 160  *      set_selection_user      -       set the current selection.
 161  *      @sel: user selection info
 162  *      @tty: the console tty
 163  *
 164  *      Invoked by the ioctl handle for the vt layer.
 165  *
 166  *      The entire selection process is managed under the console_lock. It's
 167  *       a lot under the lock but its hardly a performance path
 168  */
 169 int set_selection_user(const struct tiocl_selection __user *sel,
 170                        struct tty_struct *tty)
 171 {
 172         struct tiocl_selection v;
 173
 174         if (copy_from_user(&v, sel, sizeof(*sel)))
 175                 return -EFAULT;
 176
 177         return set_selection_kernel(&v, tty);
 178 }
 179
 180 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
 181 {
 182         struct vc_data *vc = vc_cons[fg_console].d;
 183         int new_sel_start, new_sel_end, spc;
 184         char *bp, *obp;
 185         int i, ps, pe, multiplier;
 186         u32 c;
 187         int mode;
 188
 189         poke_blanked_console();
 190
 191         v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
 192         v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
 193         v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
 194         v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
 195         ps = v->ys * vc->vc_size_row + (v->xs << 1);
 196         pe = v->ye * vc->vc_size_row + (v->xe << 1);
 197
 198         if (v->sel_mode == TIOCL_SELCLEAR) {
 199                 /* useful for screendump without selection highlights */
 200                 clear_selection();
 201                 return 0;
 202         }
 203
 204         if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
 205                 mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
 206                              v->ys);
 207                 return 0;
 208         }
 209
 210         if (ps > pe)    /* make sel_start <= sel_end */
 211                 swap(ps, pe);
 212
 213         if (sel_cons != vc_cons[fg_console].d) {
 214                 clear_selection();
 215                 sel_cons = vc_cons[fg_console].d;
 216         }
 217         mode = vt_do_kdgkbmode(fg_console);
 218         if (mode == K_UNICODE)
 219                 use_unicode = 1;
 220         else
 221                 use_unicode = 0;
 222
 223         switch (v->sel_mode)
 224         {
 225                 case TIOCL_SELCHAR:     /* character-by-character selection */
 226                         new_sel_start = ps;
 227                         new_sel_end = pe;
 228                         break;
 229                 case TIOCL_SELWORD:     /* word-by-word selection */
 230                         spc = isspace(sel_pos(ps));
 231                         for (new_sel_start = ps; ; ps -= 2)
 232                         {
 233                                 if ((spc && !isspace(sel_pos(ps))) ||
 234                                     (!spc && !inword(sel_pos(ps))))
 235                                         break;
 236                                 new_sel_start = ps;
 237                                 if (!(ps % vc->vc_size_row))
 238                                         break;
 239                         }
 240                         spc = isspace(sel_pos(pe));
 241                         for (new_sel_end = pe; ; pe += 2)
 242                         {
 243                                 if ((spc && !isspace(sel_pos(pe))) ||
 244                                     (!spc && !inword(sel_pos(pe))))
 245                                         break;
 246                                 new_sel_end = pe;
 247                                 if (!((pe + 2) % vc->vc_size_row))
 248                                         break;
 249                         }
 250                         break;
 251                 case TIOCL_SELLINE:     /* line-by-line selection */
 252                         new_sel_start = ps - ps % vc->vc_size_row;
 253                         new_sel_end = pe + vc->vc_size_row
 254                                     - pe % vc->vc_size_row - 2;
 255                         break;
 256                 case TIOCL_SELPOINTER:
 257                         highlight_pointer(pe);
 258                         return 0;
 259                 default:
 260                         return -EINVAL;
 261         }
 262
 263         /* remove the pointer */
 264         highlight_pointer(-1);
 265
 266         /* select to end of line if on trailing space */
 267         if (new_sel_end > new_sel_start &&
 268                 !atedge(new_sel_end, vc->vc_size_row) &&
 269                 isspace(sel_pos(new_sel_end))) {
 270                 for (pe = new_sel_end + 2; ; pe += 2)
 271                         if (!isspace(sel_pos(pe)) ||
 272                             atedge(pe, vc->vc_size_row))
 273                                 break;
 274                 if (isspace(sel_pos(pe)))
 275                         new_sel_end = pe;
 276         }
 277         if (sel_start == -1)    /* no current selection */
 278                 highlight(new_sel_start, new_sel_end);
 279         else if (new_sel_start == sel_start)
 280         {
 281                 if (new_sel_end == sel_end)     /* no action required */
 282                         return 0;
 283                 else if (new_sel_end > sel_end) /* extend to right */
 284                         highlight(sel_end + 2, new_sel_end);
 285                 else                            /* contract from right */
 286                         highlight(new_sel_end + 2, sel_end);
 287         }
 288         else if (new_sel_end == sel_end)
 289         {
 290                 if (new_sel_start < sel_start)  /* extend to left */
 291                         highlight(new_sel_start, sel_start - 2);
 292                 else                            /* contract from left */
 293                         highlight(sel_start, new_sel_start - 2);
 294         }
 295         else    /* some other case; start selection from scratch */
 296         {
 297                 clear_selection();
 298                 highlight(new_sel_start, new_sel_end);
 299         }
 300         sel_start = new_sel_start;
 301         sel_end = new_sel_end;
 302
 303         /* Allocate a new buffer before freeing the old one ... */
 304         multiplier = use_unicode ? 4 : 1;  /* chars can take up to 4 bytes */
 305         bp = kmalloc_array((sel_end - sel_start) / 2 + 1, multiplier,
 306                            GFP_KERNEL);
 307         if (!bp) {
 308                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 309                 clear_selection();
 310                 return -ENOMEM;
 311         }
 312         kfree(sel_buffer);
 313         sel_buffer = bp;
 314
 315         obp = bp;
 316         for (i = sel_start; i <= sel_end; i += 2) {
 317                 c = sel_pos(i);
 318                 if (use_unicode)
 319                         bp += store_utf8(c, bp);
 320                 else
 321                         *bp++ = c;
 322                 if (!isspace(c))
 323                         obp = bp;
 324                 if (! ((i + 2) % vc->vc_size_row)) {
 325                         /* strip trailing blanks from line and add newline,
 326                            unless non-space at end of line. */
 327                         if (obp != bp) {
 328                                 bp = obp;
 329                                 *bp++ = '\r';
 330                         }
 331                         obp = bp;
 332                 }
 333         }
 334         sel_buffer_lth = bp - sel_buffer;
 335         return 0;
 336 }
 337 EXPORT_SYMBOL_GPL(set_selection_kernel);
 338
 339 /* Insert the contents of the selection buffer into the
 340  * queue of the tty associated with the current console.
 341  * Invoked by ioctl().
 342  *
 343  * Locking: called without locks. Calls the ldisc wrongly with
 344  * unsafe methods,
 345  */
 346 int paste_selection(struct tty_struct *tty)
 347 {
 348         struct vc_data *vc = tty->driver_data;
 349         int     pasted = 0;
 350         unsigned int count;
 351         struct  tty_ldisc *ld;
 352         DECLARE_WAITQUEUE(wait, current);
 353
 354         console_lock();
 355         poke_blanked_console();
 356         console_unlock();
 357
 358         ld = tty_ldisc_ref_wait(tty);
 359         if (!ld)
 360                 return -EIO;    /* ldisc was hung up */
 361         tty_buffer_lock_exclusive(&vc->port);
 362
 363         add_wait_queue(&vc->paste_wait, &wait);
 364         while (sel_buffer && sel_buffer_lth > pasted) {
 365                 set_current_state(TASK_INTERRUPTIBLE);
 366                 if (tty_throttled(tty)) {
 367                         schedule();
 368                         continue;
 369                 }
 370                 __set_current_state(TASK_RUNNING);
 371                 count = sel_buffer_lth - pasted;
 372                 count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 373                                               count);
 374                 pasted += count;
 375         }
 376         remove_wait_queue(&vc->paste_wait, &wait);
 377         __set_current_state(TASK_RUNNING);
 378
 379         tty_buffer_unlock_exclusive(&vc->port);
 380         tty_ldisc_deref(ld);
 381         return 0;
 382 }
 383 EXPORT_SYMBOL_GPL(paste_selection);