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