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/mutex.h>
  18 #include <linux/slab.h>
  19 #include <linux/types.h>
  20
  21 #include <linux/uaccess.h>
  22
  23 #include <linux/kbd_kern.h>
  24 #include <linux/vt_kern.h>
  25 #include <linux/consolemap.h>
  26 #include <linux/selection.h>
  27 #include <linux/tiocl.h>
  28 #include <linux/console.h>
  29 #include <linux/tty_flip.h>
  30
  31 #include <linux/sched/signal.h>
  32
  33 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
  34 #define isspace(c)      ((c) == ' ')
  35
  36 extern void poke_blanked_console(void);
  37
  38 /* FIXME: all this needs locking */
  39 /* Variables for selection control. */
  40 /* Use a dynamic buffer, instead of static (Dec 1994) */
  41 struct vc_data *sel_cons;               /* must not be deallocated */
  42 static int use_unicode;
  43 static volatile int sel_start = -1;     /* cleared by clear_selection */
  44 static int sel_end;
  45 static int sel_buffer_lth;
  46 static char *sel_buffer;
  47 static DEFINE_MUTEX(sel_lock);
  48
  49 /* clear_selection, highlight and highlight_pointer can be called
  50    from interrupt (via scrollback/front) */
  51
  52 /* set reverse video on characters s-e of console with selection. */
  53 static inline void highlight(const int s, const int e)
  54 {
  55         invert_screen(sel_cons, s, e-s+2, 1);
  56 }
  57
  58 /* use complementary color to show the pointer */
  59 static inline void highlight_pointer(const int where)
  60 {
  61         complement_pos(sel_cons, where);
  62 }
  63
  64 static u32
  65 sel_pos(int n)
  66 {
  67         if (use_unicode)
  68                 return screen_glyph_unicode(sel_cons, n / 2);
  69         return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
  70                                 0);
  71 }
  72
  73 /**
  74  *      clear_selection         -       remove current selection
  75  *
  76  *      Remove the current selection highlight, if any from the console
  77  *      holding the selection. The caller must hold the console lock.
  78  */
  79 void clear_selection(void)
  80 {
  81         highlight_pointer(-1); /* hide the pointer */
  82         if (sel_start != -1) {
  83                 highlight(sel_start, sel_end);
  84                 sel_start = -1;
  85         }
  86 }
  87
  88 bool vc_is_sel(struct vc_data *vc)
  89 {
  90         return vc == sel_cons;
  91 }
  92
  93 /*
  94  * User settable table: what characters are to be considered alphabetic?
  95  * 128 bits. Locked by the console lock.
  96  */
  97 static u32 inwordLut[]={
  98   0x00000000, /* control chars     */
  99   0x03FFE000, /* digits and "-./"  */
 100   0x87FFFFFE, /* uppercase and '_' */
 101   0x07FFFFFE, /* lowercase         */
 102 };
 103
 104 static inline int inword(const u32 c)
 105 {
 106         return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
 107 }
 108
 109 /**
 110  *      set loadlut             -       load the LUT table
 111  *      @p: user table
 112  *
 113  *      Load the LUT table from user space. The caller must hold the console
 114  *      lock. Make a temporary copy so a partial update doesn't make a mess.
 115  */
 116 int sel_loadlut(char __user *p)
 117 {
 118         u32 tmplut[ARRAY_SIZE(inwordLut)];
 119         if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
 120                 return -EFAULT;
 121         memcpy(inwordLut, tmplut, sizeof(inwordLut));
 122         return 0;
 123 }
 124
 125 /* does screen address p correspond to character at LH/RH edge of screen? */
 126 static inline int atedge(const int p, int size_row)
 127 {
 128         return (!(p % size_row) || !((p + 2) % size_row));
 129 }
 130
 131 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
 132 static int store_utf8(u32 c, char *p)
 133 {
 134         if (c < 0x80) {
 135                 /*  0******* */
 136                 p[0] = c;
 137                 return 1;
 138         } else if (c < 0x800) {
 139                 /* 110***** 10****** */
 140                 p[0] = 0xc0 | (c >> 6);
 141                 p[1] = 0x80 | (c & 0x3f);
 142                 return 2;
 143         } else if (c < 0x10000) {
 144                 /* 1110**** 10****** 10****** */
 145                 p[0] = 0xe0 | (c >> 12);
 146                 p[1] = 0x80 | ((c >> 6) & 0x3f);
 147                 p[2] = 0x80 | (c & 0x3f);
 148                 return 3;
 149         } else if (c < 0x110000) {
 150                 /* 11110*** 10****** 10****** 10****** */
 151                 p[0] = 0xf0 | (c >> 18);
 152                 p[1] = 0x80 | ((c >> 12) & 0x3f);
 153                 p[2] = 0x80 | ((c >> 6) & 0x3f);
 154                 p[3] = 0x80 | (c & 0x3f);
 155                 return 4;
 156         } else {
 157                 /* outside Unicode, replace with U+FFFD */
 158                 p[0] = 0xef;
 159                 p[1] = 0xbf;
 160                 p[2] = 0xbd;
 161                 return 3;
 162         }
 163 }
 164
 165 /**
 166  *      set_selection           -       set the current selection.
 167  *      @sel: user selection info
 168  *      @tty: the console tty
 169  *
 170  *      Invoked by the ioctl handle for the vt layer.
 171  *
 172  *      The entire selection process is managed under the console_lock. It's
 173  *       a lot under the lock but its hardly a performance path
 174  */
 175 static int __set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
 176 {
 177         struct vc_data *vc = vc_cons[fg_console].d;
 178         int new_sel_start, new_sel_end, spc;
 179         struct tiocl_selection v;
 180         char *bp, *obp;
 181         int i, ps, pe, multiplier;
 182         u32 c;
 183         int mode, ret = 0;
 184
 185         poke_blanked_console();
 186         if (copy_from_user(&v, sel, sizeof(*sel)))
 187                 return -EFAULT;
 188
 189         v.xs = min_t(u16, v.xs - 1, vc->vc_cols - 1);
 190         v.ys = min_t(u16, v.ys - 1, vc->vc_rows - 1);
 191         v.xe = min_t(u16, v.xe - 1, vc->vc_cols - 1);
 192         v.ye = min_t(u16, v.ye - 1, vc->vc_rows - 1);
 193         ps = v.ys * vc->vc_size_row + (v.xs << 1);
 194         pe = v.ye * vc->vc_size_row + (v.xe << 1);
 195
 196         if (v.sel_mode == TIOCL_SELCLEAR) {
 197                 /* useful for screendump without selection highlights */
 198                 clear_selection();
 199                 return 0;
 200         }
 201
 202         if (mouse_reporting() && (v.sel_mode & TIOCL_SELMOUSEREPORT)) {
 203                 mouse_report(tty, v.sel_mode & TIOCL_SELBUTTONMASK, v.xs, v.ys);
 204                 return 0;
 205         }
 206
 207         if (ps > pe)    /* make sel_start <= sel_end */
 208                 swap(ps, pe);
 209
 210         if (sel_cons != vc_cons[fg_console].d) {
 211                 clear_selection();
 212                 sel_cons = vc_cons[fg_console].d;
 213         }
 214         mode = vt_do_kdgkbmode(fg_console);
 215         if (mode == K_UNICODE)
 216                 use_unicode = 1;
 217         else
 218                 use_unicode = 0;
 219
 220         switch (v.sel_mode)
 221         {
 222                 case TIOCL_SELCHAR:     /* character-by-character selection */
 223                         new_sel_start = ps;
 224                         new_sel_end = pe;
 225                         break;
 226                 case TIOCL_SELWORD:     /* word-by-word selection */
 227                         spc = isspace(sel_pos(ps));
 228                         for (new_sel_start = ps; ; ps -= 2)
 229                         {
 230                                 if ((spc && !isspace(sel_pos(ps))) ||
 231                                     (!spc && !inword(sel_pos(ps))))
 232                                         break;
 233                                 new_sel_start = ps;
 234                                 if (!(ps % vc->vc_size_row))
 235                                         break;
 236                         }
 237                         spc = isspace(sel_pos(pe));
 238                         for (new_sel_end = pe; ; pe += 2)
 239                         {
 240                                 if ((spc && !isspace(sel_pos(pe))) ||
 241                                     (!spc && !inword(sel_pos(pe))))
 242                                         break;
 243                                 new_sel_end = pe;
 244                                 if (!((pe + 2) % vc->vc_size_row))
 245                                         break;
 246                         }
 247                         break;
 248                 case TIOCL_SELLINE:     /* line-by-line selection */
 249                         new_sel_start = ps - ps % vc->vc_size_row;
 250                         new_sel_end = pe + vc->vc_size_row
 251                                     - pe % vc->vc_size_row - 2;
 252                         break;
 253                 case TIOCL_SELPOINTER:
 254                         highlight_pointer(pe);
 255                         return 0;
 256                 default:
 257                         return -EINVAL;
 258         }
 259
 260         /* remove the pointer */
 261         highlight_pointer(-1);
 262
 263         /* select to end of line if on trailing space */
 264         if (new_sel_end > new_sel_start &&
 265                 !atedge(new_sel_end, vc->vc_size_row) &&
 266                 isspace(sel_pos(new_sel_end))) {
 267                 for (pe = new_sel_end + 2; ; pe += 2)
 268                         if (!isspace(sel_pos(pe)) ||
 269                             atedge(pe, vc->vc_size_row))
 270                                 break;
 271                 if (isspace(sel_pos(pe)))
 272                         new_sel_end = pe;
 273         }
 274         if (sel_start == -1)    /* no current selection */
 275                 highlight(new_sel_start, new_sel_end);
 276         else if (new_sel_start == sel_start)
 277         {
 278                 if (new_sel_end == sel_end)     /* no action required */
 279                         return 0;
 280                 else if (new_sel_end > sel_end) /* extend to right */
 281                         highlight(sel_end + 2, new_sel_end);
 282                 else                            /* contract from right */
 283                         highlight(new_sel_end + 2, sel_end);
 284         }
 285         else if (new_sel_end == sel_end)
 286         {
 287                 if (new_sel_start < sel_start)  /* extend to left */
 288                         highlight(new_sel_start, sel_start - 2);
 289                 else                            /* contract from left */
 290                         highlight(sel_start, new_sel_start - 2);
 291         }
 292         else    /* some other case; start selection from scratch */
 293         {
 294                 clear_selection();
 295                 highlight(new_sel_start, new_sel_end);
 296         }
 297         sel_start = new_sel_start;
 298         sel_end = new_sel_end;
 299
 300         /* Allocate a new buffer before freeing the old one ... */
 301         multiplier = use_unicode ? 4 : 1;  /* chars can take up to 4 bytes */
 302         bp = kmalloc_array((sel_end - sel_start) / 2 + 1, multiplier,
 303                            GFP_KERNEL);
 304         if (!bp) {
 305                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 306                 clear_selection();
 307                 return -ENOMEM;
 308         }
 309         kfree(sel_buffer);
 310         sel_buffer = bp;
 311
 312         obp = bp;
 313         for (i = sel_start; i <= sel_end; i += 2) {
 314                 c = sel_pos(i);
 315                 if (use_unicode)
 316                         bp += store_utf8(c, bp);
 317                 else
 318                         *bp++ = c;
 319                 if (!isspace(c))
 320                         obp = bp;
 321                 if (! ((i + 2) % vc->vc_size_row)) {
 322                         /* strip trailing blanks from line and add newline,
 323                            unless non-space at end of line. */
 324                         if (obp != bp) {
 325                                 bp = obp;
 326                                 *bp++ = '\r';
 327                         }
 328                         obp = bp;
 329                 }
 330         }
 331         sel_buffer_lth = bp - sel_buffer;
 332
 333         return ret;
 334 }
 335
 336 int set_selection(const struct tiocl_selection __user *v, struct tty_struct *tty)
 337 {
 338         int ret;
 339
 340         mutex_lock(&sel_lock);
 341         console_lock();
 342         ret = __set_selection(v, tty);
 343         console_unlock();
 344         mutex_unlock(&sel_lock);
 345
 346         return ret;
 347 }
 348
 349 /* Insert the contents of the selection buffer into the
 350  * queue of the tty associated with the current console.
 351  * Invoked by ioctl().
 352  *
 353  * Locking: called without locks. Calls the ldisc wrongly with
 354  * unsafe methods,
 355  */
 356 int paste_selection(struct tty_struct *tty)
 357 {
 358         struct vc_data *vc = tty->driver_data;
 359         int     pasted = 0;
 360         unsigned int count;
 361         struct  tty_ldisc *ld;
 362         DECLARE_WAITQUEUE(wait, current);
 363         int ret = 0;
 364
 365         console_lock();
 366         poke_blanked_console();
 367         console_unlock();
 368
 369         ld = tty_ldisc_ref_wait(tty);
 370         if (!ld)
 371                 return -EIO;    /* ldisc was hung up */
 372         tty_buffer_lock_exclusive(&vc->port);
 373
 374         add_wait_queue(&vc->paste_wait, &wait);
 375         mutex_lock(&sel_lock);
 376         while (sel_buffer && sel_buffer_lth > pasted) {
 377                 set_current_state(TASK_INTERRUPTIBLE);
 378                 if (signal_pending(current)) {
 379                         ret = -EINTR;
 380                         break;
 381                 }
 382                 if (tty_throttled(tty)) {
 383                         mutex_unlock(&sel_lock);
 384                         schedule();
 385                         mutex_lock(&sel_lock);
 386                         continue;
 387                 }
 388                 __set_current_state(TASK_RUNNING);
 389                 count = sel_buffer_lth - pasted;
 390                 count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 391                                               count);
 392                 pasted += count;
 393         }
 394         mutex_unlock(&sel_lock);
 395         remove_wait_queue(&vc->paste_wait, &wait);
 396         __set_current_state(TASK_RUNNING);
 397
 398         tty_buffer_unlock_exclusive(&vc->port);
 399         tty_ldisc_deref(ld);
 400         return ret;
 401 }