1 /*- 2 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Portions of this software were developed under sponsorship from Snow 6 * B.V., the Netherlands. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/queue.h> 37 #include <sys/sysctl.h> 38 #include <sys/systm.h> 39 #include <sys/tty.h> 40 #include <sys/uio.h> 41 42 #include <vm/uma.h> 43 44 /* 45 * TTY input queue buffering. 46 * 47 * Unlike the output queue, the input queue has more features that are 48 * needed to properly implement various features offered by the TTY 49 * interface: 50 * 51 * - Data can be removed from the tail of the queue, which is used to 52 * implement backspace. 53 * - Once in a while, input has to be `canonicalized'. When ICANON is 54 * turned on, this will be done after a CR has been inserted. 55 * Otherwise, it should be done after any character has been inserted. 56 * - The input queue can store one bit per byte, called the quoting bit. 57 * This bit is used by TTYDISC to make backspace work on quoted 58 * characters. 59 * 60 * In most cases, there is probably less input than output, so unlike 61 * the outq, we'll stick to 128 byte blocks here. 62 */ 63 64 static int ttyinq_flush_secure = 1; 65 SYSCTL_INT(_kern, OID_AUTO, tty_inq_flush_secure, CTLFLAG_RW, 66 &ttyinq_flush_secure, 0, "Zero buffers while flushing"); 67 68 #define TTYINQ_QUOTESIZE (TTYINQ_DATASIZE / BMSIZE) 69 #define BMSIZE 32 70 #define GETBIT(tib,boff) \ 71 ((tib)->tib_quotes[(boff) / BMSIZE] & (1 << ((boff) % BMSIZE))) 72 #define SETBIT(tib,boff) \ 73 ((tib)->tib_quotes[(boff) / BMSIZE] |= (1 << ((boff) % BMSIZE))) 74 #define CLRBIT(tib,boff) \ 75 ((tib)->tib_quotes[(boff) / BMSIZE] &= ~(1 << ((boff) % BMSIZE))) 76 77 struct ttyinq_block { 78 struct ttyinq_block *tib_prev; 79 struct ttyinq_block *tib_next; 80 uint32_t tib_quotes[TTYINQ_QUOTESIZE]; 81 char tib_data[TTYINQ_DATASIZE]; 82 }; 83 84 static uma_zone_t ttyinq_zone; 85 86 #define TTYINQ_INSERT_TAIL(ti, tib) do { \ 87 if (ti->ti_end == 0) { \ 88 tib->tib_prev = NULL; \ 89 tib->tib_next = ti->ti_firstblock; \ 90 ti->ti_firstblock = tib; \ 91 } else { \ 92 tib->tib_prev = ti->ti_lastblock; \ 93 tib->tib_next = ti->ti_lastblock->tib_next; \ 94 ti->ti_lastblock->tib_next = tib; \ 95 } \ 96 if (tib->tib_next != NULL) \ 97 tib->tib_next->tib_prev = tib; \ 98 ti->ti_nblocks++; \ 99 } while (0) 100 101 #define TTYINQ_REMOVE_HEAD(ti) do { \ 102 ti->ti_firstblock = ti->ti_firstblock->tib_next; \ 103 if (ti->ti_firstblock != NULL) \ 104 ti->ti_firstblock->tib_prev = NULL; \ 105 ti->ti_nblocks--; \ 106 } while (0) 107 108 #define TTYINQ_RECYCLE(ti, tib) do { \ 109 if (ti->ti_quota <= ti->ti_nblocks) \ 110 uma_zfree(ttyinq_zone, tib); \ 111 else \ 112 TTYINQ_INSERT_TAIL(ti, tib); \ 113 } while (0) 114 115 int 116 ttyinq_setsize(struct ttyinq *ti, struct tty *tp, size_t size) 117 { 118 struct ttyinq_block *tib; 119 120 ti->ti_quota = howmany(size, TTYINQ_DATASIZE); 121 122 while (ti->ti_quota > ti->ti_nblocks) { 123 /* 124 * List is getting bigger. 125 * Add new blocks to the tail of the list. 126 * 127 * We must unlock the TTY temporarily, because we need 128 * to allocate memory. This won't be a problem, because 129 * in the worst case, another thread ends up here, which 130 * may cause us to allocate too many blocks, but this 131 * will be caught by the loop below. 132 */ 133 tty_unlock(tp); 134 tib = uma_zalloc(ttyinq_zone, M_WAITOK); 135 tty_lock(tp); 136 137 if (tty_gone(tp)) { 138 uma_zfree(ttyinq_zone, tib); 139 return (ENXIO); 140 } 141 142 TTYINQ_INSERT_TAIL(ti, tib); 143 } 144 return (0); 145 } 146 147 void 148 ttyinq_free(struct ttyinq *ti) 149 { 150 struct ttyinq_block *tib; 151 152 ttyinq_flush(ti); 153 ti->ti_quota = 0; 154 155 while ((tib = ti->ti_firstblock) != NULL) { 156 TTYINQ_REMOVE_HEAD(ti); 157 uma_zfree(ttyinq_zone, tib); 158 } 159 160 MPASS(ti->ti_nblocks == 0); 161 } 162 163 int 164 ttyinq_read_uio(struct ttyinq *ti, struct tty *tp, struct uio *uio, 165 size_t rlen, size_t flen) 166 { 167 168 MPASS(rlen <= uio->uio_resid); 169 170 while (rlen > 0) { 171 int error; 172 struct ttyinq_block *tib; 173 size_t cbegin, cend, clen; 174 175 /* See if there still is data. */ 176 if (ti->ti_begin == ti->ti_linestart) 177 return (0); 178 tib = ti->ti_firstblock; 179 if (tib == NULL) 180 return (0); 181 182 /* 183 * The end address should be the lowest of these three: 184 * - The write pointer 185 * - The blocksize - we can't read beyond the block 186 * - The end address if we could perform the full read 187 */ 188 cbegin = ti->ti_begin; 189 cend = MIN(MIN(ti->ti_linestart, ti->ti_begin + rlen), 190 TTYINQ_DATASIZE); 191 clen = cend - cbegin; 192 MPASS(clen >= flen); 193 rlen -= clen; 194 195 /* 196 * We can prevent buffering in some cases: 197 * - We need to read the block until the end. 198 * - We don't need to read the block until the end, but 199 * there is no data beyond it, which allows us to move 200 * the write pointer to a new block. 201 */ 202 if (cend == TTYINQ_DATASIZE || cend == ti->ti_end) { 203 /* 204 * Fast path: zero copy. Remove the first block, 205 * so we can unlock the TTY temporarily. 206 */ 207 TTYINQ_REMOVE_HEAD(ti); 208 ti->ti_begin = 0; 209 210 /* 211 * Because we remove the first block, we must 212 * fix up the block offsets. 213 */ 214 #define CORRECT_BLOCK(t) do { \ 215 if (t <= TTYINQ_DATASIZE) \ 216 t = 0; \ 217 else \ 218 t -= TTYINQ_DATASIZE; \ 219 } while (0) 220 CORRECT_BLOCK(ti->ti_linestart); 221 CORRECT_BLOCK(ti->ti_reprint); 222 CORRECT_BLOCK(ti->ti_end); 223 #undef CORRECT_BLOCK 224 225 /* 226 * Temporary unlock and copy the data to 227 * userspace. We may need to flush trailing 228 * bytes, like EOF characters. 229 */ 230 tty_unlock(tp); 231 error = uiomove(tib->tib_data + cbegin, 232 clen - flen, uio); 233 tty_lock(tp); 234 235 /* Block can now be readded to the list. */ 236 TTYINQ_RECYCLE(ti, tib); 237 } else { 238 char ob[TTYINQ_DATASIZE - 1]; 239 240 /* 241 * Slow path: store data in a temporary buffer. 242 */ 243 memcpy(ob, tib->tib_data + cbegin, clen - flen); 244 ti->ti_begin += clen; 245 MPASS(ti->ti_begin < TTYINQ_DATASIZE); 246 247 /* Temporary unlock and copy the data to userspace. */ 248 tty_unlock(tp); 249 error = uiomove(ob, clen - flen, uio); 250 tty_lock(tp); 251 } 252 253 if (error != 0) 254 return (error); 255 if (tty_gone(tp)) 256 return (ENXIO); 257 } 258 259 return (0); 260 } 261 262 static __inline void 263 ttyinq_set_quotes(struct ttyinq_block *tib, size_t offset, 264 size_t length, int value) 265 { 266 267 if (value) { 268 /* Set the bits. */ 269 for (; length > 0; length--, offset++) 270 SETBIT(tib, offset); 271 } else { 272 /* Unset the bits. */ 273 for (; length > 0; length--, offset++) 274 CLRBIT(tib, offset); 275 } 276 } 277 278 size_t 279 ttyinq_write(struct ttyinq *ti, const void *buf, size_t nbytes, int quote) 280 { 281 const char *cbuf = buf; 282 struct ttyinq_block *tib; 283 unsigned int boff; 284 size_t l; 285 286 while (nbytes > 0) { 287 boff = ti->ti_end % TTYINQ_DATASIZE; 288 289 if (ti->ti_end == 0) { 290 /* First time we're being used or drained. */ 291 MPASS(ti->ti_begin == 0); 292 tib = ti->ti_firstblock; 293 if (tib == NULL) { 294 /* Queue has no blocks. */ 295 break; 296 } 297 ti->ti_lastblock = tib; 298 } else if (boff == 0) { 299 /* We reached the end of this block on last write. */ 300 tib = ti->ti_lastblock->tib_next; 301 if (tib == NULL) { 302 /* We've reached the watermark. */ 303 break; 304 } 305 ti->ti_lastblock = tib; 306 } else { 307 tib = ti->ti_lastblock; 308 } 309 310 /* Don't copy more than was requested. */ 311 l = MIN(nbytes, TTYINQ_DATASIZE - boff); 312 MPASS(l > 0); 313 memcpy(tib->tib_data + boff, cbuf, l); 314 315 /* Set the quoting bits for the proper region. */ 316 ttyinq_set_quotes(tib, boff, l, quote); 317 318 cbuf += l; 319 nbytes -= l; 320 ti->ti_end += l; 321 } 322 323 return (cbuf - (const char *)buf); 324 } 325 326 int 327 ttyinq_write_nofrag(struct ttyinq *ti, const void *buf, size_t nbytes, int quote) 328 { 329 size_t ret; 330 331 if (ttyinq_bytesleft(ti) < nbytes) 332 return (-1); 333 334 /* We should always be able to write it back. */ 335 ret = ttyinq_write(ti, buf, nbytes, quote); 336 MPASS(ret == nbytes); 337 338 return (0); 339 } 340 341 void 342 ttyinq_canonicalize(struct ttyinq *ti) 343 { 344 345 ti->ti_linestart = ti->ti_reprint = ti->ti_end; 346 ti->ti_startblock = ti->ti_reprintblock = ti->ti_lastblock; 347 } 348 349 size_t 350 ttyinq_findchar(struct ttyinq *ti, const char *breakc, size_t maxlen, 351 char *lastc) 352 { 353 struct ttyinq_block *tib = ti->ti_firstblock; 354 unsigned int boff = ti->ti_begin; 355 unsigned int bend = MIN(MIN(TTYINQ_DATASIZE, ti->ti_linestart), 356 ti->ti_begin + maxlen); 357 358 MPASS(maxlen > 0); 359 360 if (tib == NULL) 361 return (0); 362 363 while (boff < bend) { 364 if (strchr(breakc, tib->tib_data[boff]) && !GETBIT(tib, boff)) { 365 *lastc = tib->tib_data[boff]; 366 return (boff - ti->ti_begin + 1); 367 } 368 boff++; 369 } 370 371 /* Not found - just process the entire block. */ 372 return (bend - ti->ti_begin); 373 } 374 375 void 376 ttyinq_flush(struct ttyinq *ti) 377 { 378 struct ttyinq_block *tib; 379 380 ti->ti_begin = 0; 381 ti->ti_linestart = 0; 382 ti->ti_reprint = 0; 383 ti->ti_end = 0; 384 385 /* Zero all data in the input queue to get rid of passwords. */ 386 if (ttyinq_flush_secure) { 387 for (tib = ti->ti_firstblock; tib != NULL; tib = tib->tib_next) 388 bzero(&tib->tib_data, sizeof tib->tib_data); 389 } 390 } 391 392 int 393 ttyinq_peekchar(struct ttyinq *ti, char *c, int *quote) 394 { 395 unsigned int boff; 396 struct ttyinq_block *tib = ti->ti_lastblock; 397 398 if (ti->ti_linestart == ti->ti_end) 399 return (-1); 400 401 MPASS(ti->ti_end > 0); 402 boff = (ti->ti_end - 1) % TTYINQ_DATASIZE; 403 404 *c = tib->tib_data[boff]; 405 *quote = GETBIT(tib, boff); 406 407 return (0); 408 } 409 410 void 411 ttyinq_unputchar(struct ttyinq *ti) 412 { 413 414 MPASS(ti->ti_linestart < ti->ti_end); 415 416 if (--ti->ti_end % TTYINQ_DATASIZE == 0) { 417 /* Roll back to the previous block. */ 418 ti->ti_lastblock = ti->ti_lastblock->tib_prev; 419 /* 420 * This can only fail if we are unputchar()'ing the 421 * first character in the queue. 422 */ 423 MPASS((ti->ti_lastblock == NULL) == (ti->ti_end == 0)); 424 } 425 } 426 427 void 428 ttyinq_reprintpos_set(struct ttyinq *ti) 429 { 430 431 ti->ti_reprint = ti->ti_end; 432 ti->ti_reprintblock = ti->ti_lastblock; 433 } 434 435 void 436 ttyinq_reprintpos_reset(struct ttyinq *ti) 437 { 438 439 ti->ti_reprint = ti->ti_linestart; 440 ti->ti_reprintblock = ti->ti_startblock; 441 } 442 443 static void 444 ttyinq_line_iterate(struct ttyinq *ti, 445 ttyinq_line_iterator_t *iterator, void *data, 446 unsigned int offset, struct ttyinq_block *tib) 447 { 448 unsigned int boff; 449 450 /* Use the proper block when we're at the queue head. */ 451 if (offset == 0) 452 tib = ti->ti_firstblock; 453 454 /* Iterate all characters and call the iterator function. */ 455 for (; offset < ti->ti_end; offset++) { 456 boff = offset % TTYINQ_DATASIZE; 457 MPASS(tib != NULL); 458 459 /* Call back the iterator function. */ 460 iterator(data, tib->tib_data[boff], GETBIT(tib, boff)); 461 462 /* Last byte iterated - go to the next block. */ 463 if (boff == TTYINQ_DATASIZE - 1) 464 tib = tib->tib_next; 465 MPASS(tib != NULL); 466 } 467 } 468 469 void 470 ttyinq_line_iterate_from_linestart(struct ttyinq *ti, 471 ttyinq_line_iterator_t *iterator, void *data) 472 { 473 474 ttyinq_line_iterate(ti, iterator, data, 475 ti->ti_linestart, ti->ti_startblock); 476 } 477 478 void 479 ttyinq_line_iterate_from_reprintpos(struct ttyinq *ti, 480 ttyinq_line_iterator_t *iterator, void *data) 481 { 482 483 ttyinq_line_iterate(ti, iterator, data, 484 ti->ti_reprint, ti->ti_reprintblock); 485 } 486 487 static void 488 ttyinq_startup(void *dummy) 489 { 490 491 ttyinq_zone = uma_zcreate("ttyinq", sizeof(struct ttyinq_block), 492 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 493 } 494 495 SYSINIT(ttyinq, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyinq_startup, NULL); 496