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(u32 __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 is_space_on_vt(c) ((c) == ' ')
37
38 /* FIXME: all this needs locking */
39 static struct vc_selection {
40 struct mutex lock;
41 struct vc_data *cons; /* must not be deallocated */
42 char *buffer;
43 unsigned int buf_len;
44 volatile int start; /* cleared by clear_selection */
45 int end;
46 } vc_sel = {
47 .lock = __MUTEX_INITIALIZER(vc_sel.lock),
48 .start = -1,
49 };
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. */
highlight(const int s,const int e)55 static inline void highlight(const int s, const int e)
56 {
57 invert_screen(vc_sel.cons, s, e-s+2, true);
58 }
59
60 /* use complementary color to show the pointer */
highlight_pointer(const int where)61 static inline void highlight_pointer(const int where)
62 {
63 complement_pos(vc_sel.cons, where);
64 }
65
66 static u32
sel_pos(int n,bool unicode)67 sel_pos(int n, bool unicode)
68 {
69 if (unicode)
70 return screen_glyph_unicode(vc_sel.cons, n / 2);
71 return inverse_translate(vc_sel.cons, screen_glyph(vc_sel.cons, n),
72 false);
73 }
74
75 /**
76 * clear_selection - remove current selection
77 *
78 * Remove the current selection highlight, if any from the console holding the
79 * selection.
80 *
81 * Locking: The caller must hold the console lock.
82 */
clear_selection(void)83 void clear_selection(void)
84 {
85 highlight_pointer(-1); /* hide the pointer */
86 if (vc_sel.start != -1) {
87 highlight(vc_sel.start, vc_sel.end);
88 vc_sel.start = -1;
89 }
90 }
91 EXPORT_SYMBOL_GPL(clear_selection);
92
vc_is_sel(const struct vc_data * vc)93 bool vc_is_sel(const struct vc_data *vc)
94 {
95 return vc == vc_sel.cons;
96 }
97
98 /*
99 * User settable table: what characters are to be considered alphabetic?
100 * 128 bits. Locked by the console lock.
101 */
102 static u32 inwordLut[]={
103 0x00000000, /* control chars */
104 0x03FFE000, /* digits and "-./" */
105 0x87FFFFFE, /* uppercase and '_' */
106 0x07FFFFFE, /* lowercase */
107 };
108
inword(const u32 c)109 static inline int inword(const u32 c)
110 {
111 return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
112 }
113
114 /**
115 * sel_loadlut() - load the LUT table
116 * @lut: user table
117 *
118 * Load the LUT table from user space. Make a temporary copy so a partial
119 * update doesn't make a mess.
120 *
121 * Locking: The console lock is acquired.
122 */
sel_loadlut(u32 __user * lut)123 int sel_loadlut(u32 __user *lut)
124 {
125 u32 tmplut[ARRAY_SIZE(inwordLut)];
126
127 if (copy_from_user(tmplut, lut, sizeof(inwordLut)))
128 return -EFAULT;
129
130 console_lock();
131 memcpy(inwordLut, tmplut, sizeof(inwordLut));
132 console_unlock();
133
134 return 0;
135 }
136
137 /* does screen address p correspond to character at LH/RH edge of screen? */
atedge(const int p,int size_row)138 static inline int atedge(const int p, int size_row)
139 {
140 return (!(p % size_row) || !((p + 2) % size_row));
141 }
142
143 /* stores the char in UTF8 and returns the number of bytes used (1-4) */
store_utf8(u32 c,char * p)144 static int store_utf8(u32 c, char *p)
145 {
146 if (c < 0x80) {
147 /* 0******* */
148 p[0] = c;
149 return 1;
150 } else if (c < 0x800) {
151 /* 110***** 10****** */
152 p[0] = 0xc0 | (c >> 6);
153 p[1] = 0x80 | (c & 0x3f);
154 return 2;
155 } else if (c < 0x10000) {
156 /* 1110**** 10****** 10****** */
157 p[0] = 0xe0 | (c >> 12);
158 p[1] = 0x80 | ((c >> 6) & 0x3f);
159 p[2] = 0x80 | (c & 0x3f);
160 return 3;
161 } else if (c < 0x110000) {
162 /* 11110*** 10****** 10****** 10****** */
163 p[0] = 0xf0 | (c >> 18);
164 p[1] = 0x80 | ((c >> 12) & 0x3f);
165 p[2] = 0x80 | ((c >> 6) & 0x3f);
166 p[3] = 0x80 | (c & 0x3f);
167 return 4;
168 } else {
169 /* outside Unicode, replace with U+FFFD */
170 p[0] = 0xef;
171 p[1] = 0xbf;
172 p[2] = 0xbd;
173 return 3;
174 }
175 }
176
177 /**
178 * set_selection_user - set the current selection.
179 * @sel: user selection info
180 * @tty: the console tty
181 *
182 * Invoked by the ioctl handle for the vt layer.
183 *
184 * Locking: The entire selection process is managed under the console_lock.
185 * It's a lot under the lock but its hardly a performance path.
186 */
set_selection_user(const struct tiocl_selection __user * sel,struct tty_struct * tty)187 int set_selection_user(const struct tiocl_selection __user *sel,
188 struct tty_struct *tty)
189 {
190 struct tiocl_selection v;
191
192 if (copy_from_user(&v, sel, sizeof(*sel)))
193 return -EFAULT;
194
195 /*
196 * TIOCL_SELCLEAR and TIOCL_SELPOINTER are OK to use without
197 * CAP_SYS_ADMIN as they do not modify the selection.
198 */
199 switch (v.sel_mode) {
200 case TIOCL_SELCLEAR:
201 case TIOCL_SELPOINTER:
202 break;
203 default:
204 if (!capable(CAP_SYS_ADMIN))
205 return -EPERM;
206 }
207
208 return set_selection_kernel(&v, tty);
209 }
210
vc_selection_store_chars(struct vc_data * vc,bool unicode)211 static int vc_selection_store_chars(struct vc_data *vc, bool unicode)
212 {
213 char *bp, *obp;
214 unsigned int i;
215
216 /* Allocate a new buffer before freeing the old one ... */
217 /* chars can take up to 4 bytes with unicode */
218 bp = kmalloc_array((vc_sel.end - vc_sel.start) / 2 + 1, unicode ? 4 : 1,
219 GFP_KERNEL | __GFP_NOWARN);
220 if (!bp) {
221 printk(KERN_WARNING "selection: kmalloc() failed\n");
222 clear_selection();
223 return -ENOMEM;
224 }
225 kfree(vc_sel.buffer);
226 vc_sel.buffer = bp;
227
228 obp = bp;
229 for (i = vc_sel.start; i <= vc_sel.end; i += 2) {
230 u32 c = sel_pos(i, unicode);
231 if (unicode)
232 bp += store_utf8(c, bp);
233 else
234 *bp++ = c;
235 if (!is_space_on_vt(c))
236 obp = bp;
237 if (!((i + 2) % vc->vc_size_row)) {
238 /* strip trailing blanks from line and add newline,
239 unless non-space at end of line. */
240 if (obp != bp) {
241 bp = obp;
242 *bp++ = '\r';
243 }
244 obp = bp;
245 }
246 }
247 vc_sel.buf_len = bp - vc_sel.buffer;
248
249 return 0;
250 }
251
vc_do_selection(struct vc_data * vc,unsigned short mode,int ps,int pe)252 static int vc_do_selection(struct vc_data *vc, unsigned short mode, int ps,
253 int pe)
254 {
255 int new_sel_start, new_sel_end, spc;
256 bool unicode = vt_do_kdgkbmode(fg_console) == K_UNICODE;
257
258 switch (mode) {
259 case TIOCL_SELCHAR: /* character-by-character selection */
260 new_sel_start = ps;
261 new_sel_end = pe;
262 break;
263 case TIOCL_SELWORD: /* word-by-word selection */
264 spc = is_space_on_vt(sel_pos(ps, unicode));
265 for (new_sel_start = ps; ; ps -= 2) {
266 if ((spc && !is_space_on_vt(sel_pos(ps, unicode))) ||
267 (!spc && !inword(sel_pos(ps, unicode))))
268 break;
269 new_sel_start = ps;
270 if (!(ps % vc->vc_size_row))
271 break;
272 }
273
274 spc = is_space_on_vt(sel_pos(pe, unicode));
275 for (new_sel_end = pe; ; pe += 2) {
276 if ((spc && !is_space_on_vt(sel_pos(pe, unicode))) ||
277 (!spc && !inword(sel_pos(pe, unicode))))
278 break;
279 new_sel_end = pe;
280 if (!((pe + 2) % vc->vc_size_row))
281 break;
282 }
283 break;
284 case TIOCL_SELLINE: /* line-by-line selection */
285 new_sel_start = rounddown(ps, vc->vc_size_row);
286 new_sel_end = rounddown(pe, vc->vc_size_row) +
287 vc->vc_size_row - 2;
288 break;
289 case TIOCL_SELPOINTER:
290 highlight_pointer(pe);
291 return 0;
292 default:
293 return -EINVAL;
294 }
295
296 /* remove the pointer */
297 highlight_pointer(-1);
298
299 /* select to end of line if on trailing space */
300 if (new_sel_end > new_sel_start &&
301 !atedge(new_sel_end, vc->vc_size_row) &&
302 is_space_on_vt(sel_pos(new_sel_end, unicode))) {
303 for (pe = new_sel_end + 2; ; pe += 2)
304 if (!is_space_on_vt(sel_pos(pe, unicode)) ||
305 atedge(pe, vc->vc_size_row))
306 break;
307 if (is_space_on_vt(sel_pos(pe, unicode)))
308 new_sel_end = pe;
309 }
310 if (vc_sel.start == -1) /* no current selection */
311 highlight(new_sel_start, new_sel_end);
312 else if (new_sel_start == vc_sel.start)
313 {
314 if (new_sel_end == vc_sel.end) /* no action required */
315 return 0;
316 else if (new_sel_end > vc_sel.end) /* extend to right */
317 highlight(vc_sel.end + 2, new_sel_end);
318 else /* contract from right */
319 highlight(new_sel_end + 2, vc_sel.end);
320 }
321 else if (new_sel_end == vc_sel.end)
322 {
323 if (new_sel_start < vc_sel.start) /* extend to left */
324 highlight(new_sel_start, vc_sel.start - 2);
325 else /* contract from left */
326 highlight(vc_sel.start, new_sel_start - 2);
327 }
328 else /* some other case; start selection from scratch */
329 {
330 clear_selection();
331 highlight(new_sel_start, new_sel_end);
332 }
333 vc_sel.start = new_sel_start;
334 vc_sel.end = new_sel_end;
335
336 return vc_selection_store_chars(vc, unicode);
337 }
338
vc_selection(struct vc_data * vc,struct tiocl_selection * v,struct tty_struct * tty)339 static int vc_selection(struct vc_data *vc, struct tiocl_selection *v,
340 struct tty_struct *tty)
341 {
342 int ps, pe;
343
344 poke_blanked_console();
345
346 if (v->sel_mode == TIOCL_SELCLEAR) {
347 /* useful for screendump without selection highlights */
348 clear_selection();
349 return 0;
350 }
351
352 v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
353 v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
354 v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
355 v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
356
357 if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
358 mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
359 v->ys);
360 return 0;
361 }
362
363 ps = v->ys * vc->vc_size_row + (v->xs << 1);
364 pe = v->ye * vc->vc_size_row + (v->xe << 1);
365 if (ps > pe) /* make vc_sel.start <= vc_sel.end */
366 swap(ps, pe);
367
368 if (vc_sel.cons != vc) {
369 clear_selection();
370 vc_sel.cons = vc;
371 }
372
373 return vc_do_selection(vc, v->sel_mode, ps, pe);
374 }
375
set_selection_kernel(struct tiocl_selection * v,struct tty_struct * tty)376 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
377 {
378 int ret;
379
380 mutex_lock(&vc_sel.lock);
381 console_lock();
382 ret = vc_selection(vc_cons[fg_console].d, v, tty);
383 console_unlock();
384 mutex_unlock(&vc_sel.lock);
385
386 return ret;
387 }
388 EXPORT_SYMBOL_GPL(set_selection_kernel);
389
390 /* Insert the contents of the selection buffer into the
391 * queue of the tty associated with the current console.
392 * Invoked by ioctl().
393 *
394 * Locking: called without locks. Calls the ldisc wrongly with
395 * unsafe methods,
396 */
paste_selection(struct tty_struct * tty)397 int paste_selection(struct tty_struct *tty)
398 {
399 struct vc_data *vc = tty->driver_data;
400 int pasted = 0;
401 size_t count;
402 struct tty_ldisc *ld;
403 DECLARE_WAITQUEUE(wait, current);
404 int ret = 0;
405
406 bool bp = vc->vc_bracketed_paste;
407 static const char bracketed_paste_start[] = "\033[200~";
408 static const char bracketed_paste_end[] = "\033[201~";
409 const char *bps = bp ? bracketed_paste_start : NULL;
410 const char *bpe = bp ? bracketed_paste_end : NULL;
411
412 console_lock();
413 poke_blanked_console();
414 console_unlock();
415
416 ld = tty_ldisc_ref_wait(tty);
417 if (!ld)
418 return -EIO; /* ldisc was hung up */
419 tty_buffer_lock_exclusive(&vc->port);
420
421 add_wait_queue(&vc->paste_wait, &wait);
422 mutex_lock(&vc_sel.lock);
423 while (vc_sel.buffer && (vc_sel.buf_len > pasted || bpe)) {
424 set_current_state(TASK_INTERRUPTIBLE);
425 if (signal_pending(current)) {
426 ret = -EINTR;
427 break;
428 }
429 if (tty_throttled(tty)) {
430 mutex_unlock(&vc_sel.lock);
431 schedule();
432 mutex_lock(&vc_sel.lock);
433 continue;
434 }
435 __set_current_state(TASK_RUNNING);
436
437 if (bps) {
438 bps += tty_ldisc_receive_buf(ld, bps, NULL, strlen(bps));
439 if (*bps != '\0')
440 continue;
441 bps = NULL;
442 }
443
444 count = vc_sel.buf_len - pasted;
445 if (count) {
446 pasted += tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted,
447 NULL, count);
448 if (vc_sel.buf_len > pasted)
449 continue;
450 }
451
452 if (bpe) {
453 bpe += tty_ldisc_receive_buf(ld, bpe, NULL, strlen(bpe));
454 if (*bpe == '\0')
455 bpe = NULL;
456 }
457 }
458 mutex_unlock(&vc_sel.lock);
459 remove_wait_queue(&vc->paste_wait, &wait);
460 __set_current_state(TASK_RUNNING);
461
462 tty_buffer_unlock_exclusive(&vc->port);
463 tty_ldisc_deref(ld);
464 return ret;
465 }
466 EXPORT_SYMBOL_GPL(paste_selection);
467