drivers/tty/vt/selection.c

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This source file includes following definitions.
highlight
highlight_pointer
sel_pos
clear_selection
vc_is_sel
inword
sel_loadlut
atedge
store_utf8
set_selection_user
__set_selection_kernel
set_selection_kernel
paste_selection
   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/mutex.h>
  20 #include <linux/slab.h>
  21 #include <linux/types.h>
  22 
  23 #include <linux/uaccess.h>
  24 
  25 #include <linux/kbd_kern.h>
  26 #include <linux/vt_kern.h>
  27 #include <linux/consolemap.h>
  28 #include <linux/selection.h>
  29 #include <linux/tiocl.h>
  30 #include <linux/console.h>
  31 #include <linux/tty_flip.h>
  32 
  33 #include <linux/sched/signal.h>
  34 
  35 /* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
  36 #define isspace(c)      ((c) == ' ')
  37 
  38 extern void poke_blanked_console(void);
  39 
  40 /* FIXME: all this needs locking */
  41 /* Variables for selection control. */
  42 /* Use a dynamic buffer, instead of static (Dec 1994) */
  43 struct vc_data *sel_cons;               /* must not be deallocated */
  44 static int use_unicode;
  45 static volatile int sel_start = -1;     /* cleared by clear_selection */
  46 static int sel_end;
  47 static int sel_buffer_lth;
  48 static char *sel_buffer;
  49 static DEFINE_MUTEX(sel_lock);
  50 
  51 /* clear_selection, highlight and highlight_pointer can be called
  52    from interrupt (via scrollback/front) */
  53 
  54 /* set reverse video on characters s-e of console with selection. */
  55 static inline void highlight(const int s, const int e)
  56 {
  57         invert_screen(sel_cons, s, e-s+2, 1);
  58 }
  59 
  60 /* use complementary color to show the pointer */
  61 static inline void highlight_pointer(const int where)
  62 {
  63         complement_pos(sel_cons, where);
  64 }
  65 
  66 static u32
  67 sel_pos(int n)
  68 {
  69         if (use_unicode)
  70                 return screen_glyph_unicode(sel_cons, n / 2);
  71         return inverse_translate(sel_cons, screen_glyph(sel_cons, n),
  72                                 0);
  73 }
  74 
  75 /**
  76  *      clear_selection         -       remove current selection
  77  *
  78  *      Remove the current selection highlight, if any from the console
  79  *      holding the selection. The caller must hold the console lock.
  80  */
  81 void clear_selection(void)
  82 {
  83         highlight_pointer(-1); /* hide the pointer */
  84         if (sel_start != -1) {
  85                 highlight(sel_start, sel_end);
  86                 sel_start = -1;
  87         }
  88 }
  89 EXPORT_SYMBOL_GPL(clear_selection);
  90 
  91 bool vc_is_sel(struct vc_data *vc)
  92 {
  93         return vc == sel_cons;
  94 }
  95 
  96 /*
  97  * User settable table: what characters are to be considered alphabetic?
  98  * 128 bits. Locked by the console lock.
  99  */
 100 static u32 inwordLut[]={
 101   0x00000000, /* control chars     */
 102   0x03FFE000, /* digits and "-./"  */
 103   0x87FFFFFE, /* uppercase and '_' */
 104   0x07FFFFFE, /* lowercase         */
 105 };
 106 
 107 static inline int inword(const u32 c)
 108 {
 109         return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
 110 }
 111 
 112 /**
 113  *      set loadlut             -       load the LUT table
 114  *      @p: user table
 115  *
 116  *      Load the LUT table from user space. The caller must hold the console
 117  *      lock. Make a temporary copy so a partial update doesn't make a mess.
 118  */
 119 int sel_loadlut(char __user *p)
 120 {
 121         u32 tmplut[ARRAY_SIZE(inwordLut)];
 122         if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
 123                 return -EFAULT;
 124         memcpy(inwordLut, tmplut, sizeof(inwordLut));
 125         return 0;
 126 }
 127 
 128 /* does screen address p correspond to character at LH/RH edge of screen? */
 129 static inline int atedge(const int p, int size_row)
 130 {
 131         return (!(p % size_row) || !((p + 2) % size_row));
 132 }
 133 
 134 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
 135 static int store_utf8(u32 c, char *p)
 136 {
 137         if (c < 0x80) {
 138                 /*  0******* */
 139                 p[0] = c;
 140                 return 1;
 141         } else if (c < 0x800) {
 142                 /* 110***** 10****** */
 143                 p[0] = 0xc0 | (c >> 6);
 144                 p[1] = 0x80 | (c & 0x3f);
 145                 return 2;
 146         } else if (c < 0x10000) {
 147                 /* 1110**** 10****** 10****** */
 148                 p[0] = 0xe0 | (c >> 12);
 149                 p[1] = 0x80 | ((c >> 6) & 0x3f);
 150                 p[2] = 0x80 | (c & 0x3f);
 151                 return 3;
 152         } else if (c < 0x110000) {
 153                 /* 11110*** 10****** 10****** 10****** */
 154                 p[0] = 0xf0 | (c >> 18);
 155                 p[1] = 0x80 | ((c >> 12) & 0x3f);
 156                 p[2] = 0x80 | ((c >> 6) & 0x3f);
 157                 p[3] = 0x80 | (c & 0x3f);
 158                 return 4;
 159         } else {
 160                 /* outside Unicode, replace with U+FFFD */
 161                 p[0] = 0xef;
 162                 p[1] = 0xbf;
 163                 p[2] = 0xbd;
 164                 return 3;
 165         }
 166 }
 167 
 168 /**
 169  *      set_selection_user      -       set the current selection.
 170  *      @sel: user selection info
 171  *      @tty: the console tty
 172  *
 173  *      Invoked by the ioctl handle for the vt layer.
 174  *
 175  *      The entire selection process is managed under the console_lock. It's
 176  *       a lot under the lock but its hardly a performance path
 177  */
 178 int set_selection_user(const struct tiocl_selection __user *sel,
 179                        struct tty_struct *tty)
 180 {
 181         struct tiocl_selection v;
 182 
 183         if (copy_from_user(&v, sel, sizeof(*sel)))
 184                 return -EFAULT;
 185 
 186         return set_selection_kernel(&v, tty);
 187 }
 188 
 189 static int __set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
 190 {
 191         struct vc_data *vc = vc_cons[fg_console].d;
 192         int new_sel_start, new_sel_end, spc;
 193         char *bp, *obp;
 194         int i, ps, pe, multiplier;
 195         u32 c;
 196         int mode, ret = 0;
 197 
 198         poke_blanked_console();
 199 
 200         v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
 201         v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
 202         v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
 203         v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
 204         ps = v->ys * vc->vc_size_row + (v->xs << 1);
 205         pe = v->ye * vc->vc_size_row + (v->xe << 1);
 206 
 207         if (v->sel_mode == TIOCL_SELCLEAR) {
 208                 /* useful for screendump without selection highlights */
 209                 clear_selection();
 210                 return 0;
 211         }
 212 
 213         if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
 214                 mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
 215                              v->ys);
 216                 return 0;
 217         }
 218 
 219         if (ps > pe)    /* make sel_start <= sel_end */
 220                 swap(ps, pe);
 221 
 222         if (sel_cons != vc_cons[fg_console].d) {
 223                 clear_selection();
 224                 sel_cons = vc_cons[fg_console].d;
 225         }
 226         mode = vt_do_kdgkbmode(fg_console);
 227         if (mode == K_UNICODE)
 228                 use_unicode = 1;
 229         else
 230                 use_unicode = 0;
 231 
 232         switch (v->sel_mode)
 233         {
 234                 case TIOCL_SELCHAR:     /* character-by-character selection */
 235                         new_sel_start = ps;
 236                         new_sel_end = pe;
 237                         break;
 238                 case TIOCL_SELWORD:     /* word-by-word selection */
 239                         spc = isspace(sel_pos(ps));
 240                         for (new_sel_start = ps; ; ps -= 2)
 241                         {
 242                                 if ((spc && !isspace(sel_pos(ps))) ||
 243                                     (!spc && !inword(sel_pos(ps))))
 244                                         break;
 245                                 new_sel_start = ps;
 246                                 if (!(ps % vc->vc_size_row))
 247                                         break;
 248                         }
 249                         spc = isspace(sel_pos(pe));
 250                         for (new_sel_end = pe; ; pe += 2)
 251                         {
 252                                 if ((spc && !isspace(sel_pos(pe))) ||
 253                                     (!spc && !inword(sel_pos(pe))))
 254                                         break;
 255                                 new_sel_end = pe;
 256                                 if (!((pe + 2) % vc->vc_size_row))
 257                                         break;
 258                         }
 259                         break;
 260                 case TIOCL_SELLINE:     /* line-by-line selection */
 261                         new_sel_start = ps - ps % vc->vc_size_row;
 262                         new_sel_end = pe + vc->vc_size_row
 263                                     - pe % vc->vc_size_row - 2;
 264                         break;
 265                 case TIOCL_SELPOINTER:
 266                         highlight_pointer(pe);
 267                         return 0;
 268                 default:
 269                         return -EINVAL;
 270         }
 271 
 272         /* remove the pointer */
 273         highlight_pointer(-1);
 274 
 275         /* select to end of line if on trailing space */
 276         if (new_sel_end > new_sel_start &&
 277                 !atedge(new_sel_end, vc->vc_size_row) &&
 278                 isspace(sel_pos(new_sel_end))) {
 279                 for (pe = new_sel_end + 2; ; pe += 2)
 280                         if (!isspace(sel_pos(pe)) ||
 281                             atedge(pe, vc->vc_size_row))
 282                                 break;
 283                 if (isspace(sel_pos(pe)))
 284                         new_sel_end = pe;
 285         }
 286         if (sel_start == -1)    /* no current selection */
 287                 highlight(new_sel_start, new_sel_end);
 288         else if (new_sel_start == sel_start)
 289         {
 290                 if (new_sel_end == sel_end)     /* no action required */
 291                         return 0;
 292                 else if (new_sel_end > sel_end) /* extend to right */
 293                         highlight(sel_end + 2, new_sel_end);
 294                 else                            /* contract from right */
 295                         highlight(new_sel_end + 2, sel_end);
 296         }
 297         else if (new_sel_end == sel_end)
 298         {
 299                 if (new_sel_start < sel_start)  /* extend to left */
 300                         highlight(new_sel_start, sel_start - 2);
 301                 else                            /* contract from left */
 302                         highlight(sel_start, new_sel_start - 2);
 303         }
 304         else    /* some other case; start selection from scratch */
 305         {
 306                 clear_selection();
 307                 highlight(new_sel_start, new_sel_end);
 308         }
 309         sel_start = new_sel_start;
 310         sel_end = new_sel_end;
 311 
 312         /* Allocate a new buffer before freeing the old one ... */
 313         multiplier = use_unicode ? 4 : 1;  /* chars can take up to 4 bytes */
 314         bp = kmalloc_array((sel_end - sel_start) / 2 + 1, multiplier,
 315                            GFP_KERNEL);
 316         if (!bp) {
 317                 printk(KERN_WARNING "selection: kmalloc() failed\n");
 318                 clear_selection();
 319                 return -ENOMEM;
 320         }
 321         kfree(sel_buffer);
 322         sel_buffer = bp;
 323 
 324         obp = bp;
 325         for (i = sel_start; i <= sel_end; i += 2) {
 326                 c = sel_pos(i);
 327                 if (use_unicode)
 328                         bp += store_utf8(c, bp);
 329                 else
 330                         *bp++ = c;
 331                 if (!isspace(c))
 332                         obp = bp;
 333                 if (! ((i + 2) % vc->vc_size_row)) {
 334                         /* strip trailing blanks from line and add newline,
 335                            unless non-space at end of line. */
 336                         if (obp != bp) {
 337                                 bp = obp;
 338                                 *bp++ = '\r';
 339                         }
 340                         obp = bp;
 341                 }
 342         }
 343         sel_buffer_lth = bp - sel_buffer;
 344 
 345         return ret;
 346 }
 347 
 348 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
 349 {
 350         int ret;
 351 
 352         mutex_lock(&sel_lock);
 353         console_lock();
 354         ret = __set_selection_kernel(v, tty);
 355         console_unlock();
 356         mutex_unlock(&sel_lock);
 357 
 358         return ret;
 359 }
 360 EXPORT_SYMBOL_GPL(set_selection_kernel);
 361 
 362 /* Insert the contents of the selection buffer into the
 363  * queue of the tty associated with the current console.
 364  * Invoked by ioctl().
 365  *
 366  * Locking: called without locks. Calls the ldisc wrongly with
 367  * unsafe methods,
 368  */
 369 int paste_selection(struct tty_struct *tty)
 370 {
 371         struct vc_data *vc = tty->driver_data;
 372         int     pasted = 0;
 373         unsigned int count;
 374         struct  tty_ldisc *ld;
 375         DECLARE_WAITQUEUE(wait, current);
 376         int ret = 0;
 377 
 378         console_lock();
 379         poke_blanked_console();
 380         console_unlock();
 381 
 382         ld = tty_ldisc_ref_wait(tty);
 383         if (!ld)
 384                 return -EIO;    /* ldisc was hung up */
 385         tty_buffer_lock_exclusive(&vc->port);
 386 
 387         add_wait_queue(&vc->paste_wait, &wait);
 388         mutex_lock(&sel_lock);
 389         while (sel_buffer && sel_buffer_lth > pasted) {
 390                 set_current_state(TASK_INTERRUPTIBLE);
 391                 if (signal_pending(current)) {
 392                         ret = -EINTR;
 393                         break;
 394                 }
 395                 if (tty_throttled(tty)) {
 396                         mutex_unlock(&sel_lock);
 397                         schedule();
 398                         mutex_lock(&sel_lock);
 399                         continue;
 400                 }
 401                 __set_current_state(TASK_RUNNING);
 402                 count = sel_buffer_lth - pasted;
 403                 count = tty_ldisc_receive_buf(ld, sel_buffer + pasted, NULL,
 404                                               count);
 405                 pasted += count;
 406         }
 407         mutex_unlock(&sel_lock);
 408         remove_wait_queue(&vc->paste_wait, &wait);
 409         __set_current_state(TASK_RUNNING);
 410 
 411         tty_buffer_unlock_exclusive(&vc->port);
 412         tty_ldisc_deref(ld);
 413         return ret;
 414 }
 415 EXPORT_SYMBOL_GPL(paste_selection);
/* [<][>][^][v][top][bottom][index][help] */
root/drivers/tty/vt/selection.c

DEFINITIONS
