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 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
79 * holding the selection. The caller must hold the console lock.
80 */
clear_selection(void)81 void clear_selection(void)
82 {
83 highlight_pointer(-1); /* hide the pointer */
84 if (vc_sel.start != -1) {
85 highlight(vc_sel.start, vc_sel.end);
86 vc_sel.start = -1;
87 }
88 }
89 EXPORT_SYMBOL_GPL(clear_selection);
90
vc_is_sel(struct vc_data * vc)91 bool vc_is_sel(struct vc_data *vc)
92 {
93 return vc == 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
inword(const u32 c)107 static inline int inword(const u32 c)
108 {
109 return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
110 }
111
112 /**
113 * sel_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 */
sel_loadlut(char __user * p)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? */
atedge(const int p,int size_row)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) */
store_utf8(u32 c,char * p)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 */
set_selection_user(const struct tiocl_selection __user * sel,struct tty_struct * tty)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
vc_selection_store_chars(struct vc_data * vc,bool unicode)189 static int vc_selection_store_chars(struct vc_data *vc, bool unicode)
190 {
191 char *bp, *obp;
192 unsigned int i;
193
194 /* Allocate a new buffer before freeing the old one ... */
195 /* chars can take up to 4 bytes with unicode */
196 bp = kmalloc_array((vc_sel.end - vc_sel.start) / 2 + 1, unicode ? 4 : 1,
197 GFP_KERNEL | __GFP_NOWARN);
198 if (!bp) {
199 printk(KERN_WARNING "selection: kmalloc() failed\n");
200 clear_selection();
201 return -ENOMEM;
202 }
203 kfree(vc_sel.buffer);
204 vc_sel.buffer = bp;
205
206 obp = bp;
207 for (i = vc_sel.start; i <= vc_sel.end; i += 2) {
208 u32 c = sel_pos(i, unicode);
209 if (unicode)
210 bp += store_utf8(c, bp);
211 else
212 *bp++ = c;
213 if (!is_space_on_vt(c))
214 obp = bp;
215 if (!((i + 2) % vc->vc_size_row)) {
216 /* strip trailing blanks from line and add newline,
217 unless non-space at end of line. */
218 if (obp != bp) {
219 bp = obp;
220 *bp++ = '\r';
221 }
222 obp = bp;
223 }
224 }
225 vc_sel.buf_len = bp - vc_sel.buffer;
226
227 return 0;
228 }
229
vc_do_selection(struct vc_data * vc,unsigned short mode,int ps,int pe)230 static int vc_do_selection(struct vc_data *vc, unsigned short mode, int ps,
231 int pe)
232 {
233 int new_sel_start, new_sel_end, spc;
234 bool unicode = vt_do_kdgkbmode(fg_console) == K_UNICODE;
235
236 switch (mode) {
237 case TIOCL_SELCHAR: /* character-by-character selection */
238 new_sel_start = ps;
239 new_sel_end = pe;
240 break;
241 case TIOCL_SELWORD: /* word-by-word selection */
242 spc = is_space_on_vt(sel_pos(ps, unicode));
243 for (new_sel_start = ps; ; ps -= 2) {
244 if ((spc && !is_space_on_vt(sel_pos(ps, unicode))) ||
245 (!spc && !inword(sel_pos(ps, unicode))))
246 break;
247 new_sel_start = ps;
248 if (!(ps % vc->vc_size_row))
249 break;
250 }
251
252 spc = is_space_on_vt(sel_pos(pe, unicode));
253 for (new_sel_end = pe; ; pe += 2) {
254 if ((spc && !is_space_on_vt(sel_pos(pe, unicode))) ||
255 (!spc && !inword(sel_pos(pe, unicode))))
256 break;
257 new_sel_end = pe;
258 if (!((pe + 2) % vc->vc_size_row))
259 break;
260 }
261 break;
262 case TIOCL_SELLINE: /* line-by-line selection */
263 new_sel_start = rounddown(ps, vc->vc_size_row);
264 new_sel_end = rounddown(pe, vc->vc_size_row) +
265 vc->vc_size_row - 2;
266 break;
267 case TIOCL_SELPOINTER:
268 highlight_pointer(pe);
269 return 0;
270 default:
271 return -EINVAL;
272 }
273
274 /* remove the pointer */
275 highlight_pointer(-1);
276
277 /* select to end of line if on trailing space */
278 if (new_sel_end > new_sel_start &&
279 !atedge(new_sel_end, vc->vc_size_row) &&
280 is_space_on_vt(sel_pos(new_sel_end, unicode))) {
281 for (pe = new_sel_end + 2; ; pe += 2)
282 if (!is_space_on_vt(sel_pos(pe, unicode)) ||
283 atedge(pe, vc->vc_size_row))
284 break;
285 if (is_space_on_vt(sel_pos(pe, unicode)))
286 new_sel_end = pe;
287 }
288 if (vc_sel.start == -1) /* no current selection */
289 highlight(new_sel_start, new_sel_end);
290 else if (new_sel_start == vc_sel.start)
291 {
292 if (new_sel_end == vc_sel.end) /* no action required */
293 return 0;
294 else if (new_sel_end > vc_sel.end) /* extend to right */
295 highlight(vc_sel.end + 2, new_sel_end);
296 else /* contract from right */
297 highlight(new_sel_end + 2, vc_sel.end);
298 }
299 else if (new_sel_end == vc_sel.end)
300 {
301 if (new_sel_start < vc_sel.start) /* extend to left */
302 highlight(new_sel_start, vc_sel.start - 2);
303 else /* contract from left */
304 highlight(vc_sel.start, new_sel_start - 2);
305 }
306 else /* some other case; start selection from scratch */
307 {
308 clear_selection();
309 highlight(new_sel_start, new_sel_end);
310 }
311 vc_sel.start = new_sel_start;
312 vc_sel.end = new_sel_end;
313
314 return vc_selection_store_chars(vc, unicode);
315 }
316
vc_selection(struct vc_data * vc,struct tiocl_selection * v,struct tty_struct * tty)317 static int vc_selection(struct vc_data *vc, struct tiocl_selection *v,
318 struct tty_struct *tty)
319 {
320 int ps, pe;
321
322 poke_blanked_console();
323
324 if (v->sel_mode == TIOCL_SELCLEAR) {
325 /* useful for screendump without selection highlights */
326 clear_selection();
327 return 0;
328 }
329
330 v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
331 v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
332 v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
333 v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
334
335 if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
336 mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
337 v->ys);
338 return 0;
339 }
340
341 ps = v->ys * vc->vc_size_row + (v->xs << 1);
342 pe = v->ye * vc->vc_size_row + (v->xe << 1);
343 if (ps > pe) /* make vc_sel.start <= vc_sel.end */
344 swap(ps, pe);
345
346 if (vc_sel.cons != vc) {
347 clear_selection();
348 vc_sel.cons = vc;
349 }
350
351 return vc_do_selection(vc, v->sel_mode, ps, pe);
352 }
353
set_selection_kernel(struct tiocl_selection * v,struct tty_struct * tty)354 int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
355 {
356 int ret;
357
358 mutex_lock(&vc_sel.lock);
359 console_lock();
360 ret = vc_selection(vc_cons[fg_console].d, v, tty);
361 console_unlock();
362 mutex_unlock(&vc_sel.lock);
363
364 return ret;
365 }
366 EXPORT_SYMBOL_GPL(set_selection_kernel);
367
368 /* Insert the contents of the selection buffer into the
369 * queue of the tty associated with the current console.
370 * Invoked by ioctl().
371 *
372 * Locking: called without locks. Calls the ldisc wrongly with
373 * unsafe methods,
374 */
paste_selection(struct tty_struct * tty)375 int paste_selection(struct tty_struct *tty)
376 {
377 struct vc_data *vc = tty->driver_data;
378 int pasted = 0;
379 unsigned int count;
380 struct tty_ldisc *ld;
381 DECLARE_WAITQUEUE(wait, current);
382 int ret = 0;
383
384 console_lock();
385 poke_blanked_console();
386 console_unlock();
387
388 ld = tty_ldisc_ref_wait(tty);
389 if (!ld)
390 return -EIO; /* ldisc was hung up */
391 tty_buffer_lock_exclusive(&vc->port);
392
393 add_wait_queue(&vc->paste_wait, &wait);
394 mutex_lock(&vc_sel.lock);
395 while (vc_sel.buffer && vc_sel.buf_len > pasted) {
396 set_current_state(TASK_INTERRUPTIBLE);
397 if (signal_pending(current)) {
398 ret = -EINTR;
399 break;
400 }
401 if (tty_throttled(tty)) {
402 mutex_unlock(&vc_sel.lock);
403 schedule();
404 mutex_lock(&vc_sel.lock);
405 continue;
406 }
407 __set_current_state(TASK_RUNNING);
408 count = vc_sel.buf_len - pasted;
409 count = tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL,
410 count);
411 pasted += count;
412 }
413 mutex_unlock(&vc_sel.lock);
414 remove_wait_queue(&vc->paste_wait, &wait);
415 __set_current_state(TASK_RUNNING);
416
417 tty_buffer_unlock_exclusive(&vc->port);
418 tty_ldisc_deref(ld);
419 return ret;
420 }
421 EXPORT_SYMBOL_GPL(paste_selection);
422