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 new_sel_start, new_sel_end, spc;
 160         struct tiocl_selection v;
 161         char *bp, *obp;
 162         int i, ps, pe, multiplier;
 163         u16 c;
 164         int mode;
 165
 166         poke_blanked_console();
 167         if (copy_from_user(&v, sel, sizeof(*sel)))
 168                 return -EFAULT;
 169
 170         v.xs = limit(v.xs - 1, vc->vc_cols - 1);
 171         v.ys = limit(v.ys - 1, vc->vc_rows - 1);
 172         v.xe = limit(v.xe - 1, vc->vc_cols - 1);
 173         v.ye = limit(v.ye - 1, vc->vc_rows - 1);
 174         ps = v.ys * vc->vc_size_row + (v.xs << 1);
 175         pe = v.ye * vc->vc_size_row + (v.xe << 1);
 176
 177         if (v.sel_mode == TIOCL_SELCLEAR) {
 178                 /* useful for screendump without selection highlights */
 179                 clear_selection();
 180                 return 0;
 181         }
 182
 183         if (mouse_reporting() && (v.sel_mode & TIOCL_SELMOUSEREPORT)) {
 184                 mouse_report(tty, v.sel_mode & TIOCL_SELBUTTONMASK, v.xs, v.ys);
 185                 return 0;
 186         }
 187
 188         if (ps > pe)    /* make sel_start <= sel_end */
 189         {
 190                 int tmp = ps;
 191                 ps = pe;
 192                 pe = tmp;
 193         }
 194
 195         if (sel_cons != vc_cons[fg_console].d) {
 196                 clear_selection();
 197                 sel_cons = vc_cons[fg_console].d;
 198         }
 199         mode = vt_do_kdgkbmode(fg_console);
 200         if (mode == K_UNICODE)
 201                 use_unicode = 1;
 202         else
 203                 use_unicode = 0;
 204
 205         switch (v.sel_mode)
 206         {
 207                 case TIOCL_SELCHAR:     /* character-by-character selection */
 208                         new_sel_start = ps;
 209                         new_sel_end = pe;
 210                         break;
 211                 case TIOCL_SELWORD:     /* word-by-word selection */
 212                         spc = isspace(sel_pos(ps));
 213                         for (new_sel_start = ps; ; ps -= 2)
 214                         {
 215                                 if ((spc && !isspace(sel_pos(ps))) ||
 216                                     (!spc && !inword(sel_pos(ps))))
 217                                         break;
 218                                 new_sel_start = ps;
 219                                 if (!(ps % vc->vc_size_row))
 220                                         break;
 221                         }
 222                         spc = isspace(sel_pos(pe));
 223                         for (new_sel_end = pe; ; pe += 2)
 224                         {
 225                                 if ((spc && !isspace(sel_pos(pe))) ||
 226                                     (!spc && !inword(sel_pos(pe))))
 227                                         break;
 228                                 new_sel_end = pe;
 229                                 if (!((pe + 2) % vc->vc_size_row))
 230                                         break;
 231                         }
 232                         break;
 233                 case TIOCL_SELLINE:     /* line-by-line selection */
 234                         new_sel_start = ps - ps % vc->vc_size_row;
 235                         new_sel_end = pe + vc->vc_size_row
 236                                     - pe % vc->vc_size_row - 2;
 237                         break;
 238                 case TIOCL_SELPOINTER:
 239                         highlight_pointer(pe);
 240                         return 0;
 241                 default:
 242                         return -EINVAL;
 243         }
 244
 245         /* remove the pointer */
 246         highlight_pointer(-1);
 247
 248         /* select to end of line if on trailing space */
 249         if (new_sel_end > new_sel_start &&
 250                 !atedge(new_sel_end, vc->vc_size_row) &&
 251                 isspace(sel_pos(new_sel_end))) {
 252                 for (pe = new_sel_end + 2; ; pe += 2)
 253                         if (!isspace(sel_pos(pe)) ||
 254                             atedge(pe, vc->vc_size_row))
 255                                 break;
 256                 if (isspace(sel_pos(pe)))
 257                         new_sel_end = pe;
 258         }
 259         if (sel_start == -1)    /* no current selection */
 260                 highlight(new_sel_start, new_sel_end);
 261         else if (new_sel_start == sel_start)
 262         {
 263                 if (new_sel_end == sel_end)     /* no action required */
 264                         return 0;
 265                 else if (new_sel_end > sel_end) /* extend to right */
 266                         highlight(sel_end + 2, new_sel_end);
 267                 else                            /* contract from right */
 268                         highlight(new_sel_end + 2, sel_end);
 269         }
 270         else if (new_sel_end == sel_end)
 271         {
 272                 if (new_sel_start < sel_start)  /* extend to left */
 273                         highlight(new_sel_start, sel_start - 2);
 274                 else                            /* contract from left */
 275                         highlight(sel_start, new_sel_start - 2);
 276         }
 277         else    /* some other case; start selection from scratch */
 278         {
 279                 clear_selection();
 280                 highlight(new_sel_start, new_sel_end);
 281         }
 282         sel_start = new_sel_start;
 283         sel_end = new_sel_end;
 284
 285         /* Allocate a new buffer before freeing the old one ... */
 286         multiplier = use_unicode ? 3 : 1;  /* chars can take up to 3 bytes */
 287         bp = kmalloc(((sel_end-sel_start)/2+1)*multiplier, GFP_KERNEL);
 288         if (!bp) {
 289                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 290                 clear_selection();
 291                 return -ENOMEM;
 292         }
 293         kfree(sel_buffer);
 294         sel_buffer = bp;
 295
 296         obp = bp;
 297         for (i = sel_start; i <= sel_end; i += 2) {
 298                 c = sel_pos(i);
 299                 if (use_unicode)
 300                         bp += store_utf8(c, bp);
 301                 else
 302                         *bp++ = c;
 303                 if (!isspace(c))
 304                         obp = bp;
 305                 if (! ((i + 2) % vc->vc_size_row)) {
 306                         /* strip trailing blanks from line and add newline,
 307                            unless non-space at end of line. */
 308                         if (obp != bp) {
 309                                 bp = obp;
 310                                 *bp++ = '\r';
 311                         }
 312                         obp = bp;
 313                 }
 314         }
 315         sel_buffer_lth = bp - sel_buffer;
 316         return 0;
 317 }
 318
 319 /* Insert the contents of the selection buffer into the
 320  * queue of the tty associated with the current console.
 321  * Invoked by ioctl().
 322  *
 323  * Locking: called without locks. Calls the ldisc wrongly with
 324  * unsafe methods,
 325  */
 326 int paste_selection(struct tty_struct *tty)
 327 {
 328         struct vc_data *vc = tty->driver_data;
 329         int     pasted = 0;
 330         unsigned int count;
 331         struct  tty_ldisc *ld;
 332         DECLARE_WAITQUEUE(wait, current);
 333
 334         console_lock();
 335         poke_blanked_console();
 336         console_unlock();
 337
 338         ld = tty_ldisc_ref_wait(tty);
 339         if (!ld)
 340                 return -EIO;    /* ldisc was hung up */
 341         tty_buffer_lock_exclusive(&vc->port);
 342
 343         add_wait_queue(&vc->paste_wait, &wait);
 344         while (sel_buffer && sel_buffer_lth > pasted) {
 345                 set_current_state(TASK_INTERRUPTIBLE);
 346                 if (tty_throttled(tty)) {
 347                         schedule();
 348                         continue;
 349                 }
 350                 __set_current_state(TASK_RUNNING);
 351                 count = sel_buffer_lth - pasted;
 352                 count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 353                                               count);
 354                 pasted += count;
 355         }
 356         remove_wait_queue(&vc->paste_wait, &wait);
 357         __set_current_state(TASK_RUNNING);
 358
 359         tty_buffer_unlock_exclusive(&vc->port);
 360         tty_ldisc_deref(ld);
 361         return 0;
 362 }