tty_ptm.c revision 1.37.2.3
1 /* $NetBSD: tty_ptm.c,v 1.37.2.3 2016/07/26 05:54:40 pgoyette Exp $ */ 2 3 /*- 4 * Copyright (c) 2004 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: tty_ptm.c,v 1.37.2.3 2016/07/26 05:54:40 pgoyette Exp $"); 31 32 #ifdef _KERNEL_OPT 33 #include "opt_compat_netbsd.h" 34 #include "opt_ptm.h" 35 #endif 36 37 /* pty multiplexor driver /dev/ptm{,x} */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/ioctl.h> 42 #include <sys/proc.h> 43 #include <sys/tty.h> 44 #include <sys/stat.h> 45 #include <sys/file.h> 46 #include <sys/uio.h> 47 #include <sys/kernel.h> 48 #include <sys/vnode.h> 49 #include <sys/namei.h> 50 #include <sys/signalvar.h> 51 #include <sys/filedesc.h> 52 #include <sys/conf.h> 53 #include <sys/poll.h> 54 #include <sys/pty.h> 55 #include <sys/kauth.h> 56 #include <sys/localcount.h> 57 58 #include <miscfs/specfs/specdev.h> 59 60 #ifdef COMPAT_60 61 #include <compat/sys/ttycom.h> 62 #endif /* COMPAT_60 */ 63 64 #include "ioconf.h" 65 66 #ifdef DEBUG_PTM 67 #define DPRINTF(a) printf a 68 #else 69 #define DPRINTF(a) 70 #endif 71 72 #ifdef NO_DEV_PTM 73 const struct cdevsw ptm_cdevsw = { 74 DEVSW_MODULE_INIT 75 .d_open = noopen, 76 .d_close = noclose, 77 .d_read = noread, 78 .d_write = nowrite, 79 .d_ioctl = noioctl, 80 .d_stop = nostop, 81 .d_tty = notty, 82 .d_poll = nopoll, 83 .d_mmap = nommap, 84 .d_kqfilter = nokqfilter, 85 .d_discard = nodiscard, 86 .d_flag = D_TTY 87 }; 88 #else /* NO_DEV_PTM */ 89 90 static struct ptm_pty *ptm; 91 int pts_major, ptc_major; 92 93 static dev_t pty_getfree(void); 94 static int pty_alloc_master(struct lwp *, int *, dev_t *, struct mount *); 95 static int pty_alloc_slave(struct lwp *, int *, dev_t, struct mount *); 96 static int pty_vn_open(struct vnode *, struct lwp *); 97 98 int 99 pty_getmp(struct lwp *l, struct mount **mpp) 100 { 101 if (ptm == NULL) 102 return EOPNOTSUPP; 103 104 return (*ptm->getmp)(l, mpp); 105 } 106 107 dev_t 108 pty_makedev(char ms, int minor) 109 { 110 return makedev(ms == 't' ? pts_major : ptc_major, minor); 111 } 112 113 114 static dev_t 115 pty_getfree(void) 116 { 117 extern kmutex_t pt_softc_mutex; 118 int i; 119 120 mutex_enter(&pt_softc_mutex); 121 for (i = 0; i < npty; i++) { 122 if (pty_isfree(i, 0)) 123 break; 124 } 125 mutex_exit(&pt_softc_mutex); 126 return pty_makedev('t', i); 127 } 128 129 /* 130 * Hacked up version of vn_open. We _only_ handle ptys and only open 131 * them with FREAD|FWRITE and never deal with creat or stuff like that. 132 * 133 * We need it because we have to fake up root credentials to open the pty. 134 */ 135 int 136 pty_vn_open(struct vnode *vp, struct lwp *l) 137 { 138 int error; 139 140 if (vp->v_type != VCHR) { 141 vput(vp); 142 return EINVAL; 143 } 144 145 error = VOP_OPEN(vp, FREAD|FWRITE, lwp0.l_cred); 146 147 if (error) { 148 vput(vp); 149 return error; 150 } 151 152 vp->v_writecount++; 153 154 return 0; 155 } 156 157 static int 158 pty_alloc_master(struct lwp *l, int *fd, dev_t *dev, struct mount *mp) 159 { 160 int error; 161 struct file *fp; 162 struct vnode *vp; 163 int md; 164 165 if ((error = fd_allocfile(&fp, fd)) != 0) { 166 DPRINTF(("fd_allocfile %d\n", error)); 167 return error; 168 } 169 retry: 170 /* Find and open a free master pty. */ 171 *dev = pty_getfree(); 172 md = minor(*dev); 173 if ((error = pty_check(md)) != 0) { 174 DPRINTF(("pty_check %d\n", error)); 175 goto bad; 176 } 177 if (ptm == NULL) { 178 DPRINTF(("no ptm\n")); 179 error = EOPNOTSUPP; 180 goto bad; 181 } 182 if ((error = (*ptm->allocvp)(mp, l, &vp, *dev, 'p')) != 0) { 183 DPRINTF(("pty_allocvp %d\n", error)); 184 goto bad; 185 } 186 187 if ((error = pty_vn_open(vp, l)) != 0) { 188 DPRINTF(("pty_vn_open %d\n", error)); 189 /* 190 * Check if the master open failed because we lost 191 * the race to grab it. 192 */ 193 if (error != EIO) 194 goto bad; 195 error = !pty_isfree(md, 1); 196 DPRINTF(("pty_isfree %d\n", error)); 197 if (error) 198 goto retry; 199 else 200 goto bad; 201 } 202 fp->f_flag = FREAD|FWRITE; 203 fp->f_type = DTYPE_VNODE; 204 fp->f_ops = &vnops; 205 fp->f_vnode = vp; 206 VOP_UNLOCK(vp); 207 fd_affix(curproc, fp, *fd); 208 return 0; 209 bad: 210 fd_abort(curproc, fp, *fd); 211 return error; 212 } 213 214 int 215 pty_grant_slave(struct lwp *l, dev_t dev, struct mount *mp) 216 { 217 int error; 218 struct vnode *vp; 219 220 /* 221 * Open the slave. 222 * namei -> setattr -> unlock -> revoke -> vrele -> 223 * namei -> open -> unlock 224 * Three stage rocket: 225 * 1. Change the owner and permissions on the slave. 226 * 2. Revoke all the users of the slave. 227 * 3. open the slave. 228 */ 229 if (ptm == NULL) 230 return EOPNOTSUPP; 231 if ((error = (*ptm->allocvp)(mp, l, &vp, dev, 't')) != 0) 232 return error; 233 234 if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) { 235 struct vattr vattr; 236 (*ptm->getvattr)(mp, l, &vattr); 237 /* Do the VOP_SETATTR() as root. */ 238 error = VOP_SETATTR(vp, &vattr, lwp0.l_cred); 239 if (error) { 240 DPRINTF(("setattr %d\n", error)); 241 VOP_UNLOCK(vp); 242 vrele(vp); 243 return error; 244 } 245 } 246 VOP_UNLOCK(vp); 247 VOP_REVOKE(vp, REVOKEALL); 248 249 /* 250 * The vnode is useless after the revoke, we need to get it again. 251 */ 252 vrele(vp); 253 return 0; 254 } 255 256 static int 257 pty_alloc_slave(struct lwp *l, int *fd, dev_t dev, struct mount *mp) 258 { 259 int error; 260 struct file *fp; 261 struct vnode *vp; 262 263 /* Grab a filedescriptor for the slave */ 264 if ((error = fd_allocfile(&fp, fd)) != 0) { 265 DPRINTF(("fd_allocfile %d\n", error)); 266 return error; 267 } 268 269 if (ptm == NULL) { 270 error = EOPNOTSUPP; 271 goto bad; 272 } 273 274 if ((error = (*ptm->allocvp)(mp, l, &vp, dev, 't')) != 0) 275 goto bad; 276 if ((error = pty_vn_open(vp, l)) != 0) 277 goto bad; 278 279 fp->f_flag = FREAD|FWRITE; 280 fp->f_type = DTYPE_VNODE; 281 fp->f_ops = &vnops; 282 fp->f_vnode = vp; 283 VOP_UNLOCK(vp); 284 fd_affix(curproc, fp, *fd); 285 return 0; 286 bad: 287 fd_abort(curproc, fp, *fd); 288 return error; 289 } 290 291 struct ptm_pty * 292 pty_sethandler(struct ptm_pty *nptm) 293 { 294 struct ptm_pty *optm = ptm; 295 ptm = nptm; 296 return optm; 297 } 298 299 int 300 pty_fill_ptmget(struct lwp *l, dev_t dev, int cfd, int sfd, void *data, struct mount *mp) 301 { 302 struct ptmget *ptmg = data; 303 int error; 304 305 if (ptm == NULL) 306 return EOPNOTSUPP; 307 308 ptmg->cfd = cfd == -1 ? minor(dev) : cfd; 309 ptmg->sfd = sfd == -1 ? minor(dev) : sfd; 310 311 error = (*ptm->makename)(mp, l, ptmg->cn, sizeof(ptmg->cn), dev, 'p'); 312 if (error) 313 return error; 314 315 return (*ptm->makename)(mp, l, ptmg->sn, sizeof(ptmg->sn), dev, 't'); 316 } 317 318 void 319 /*ARGSUSED*/ 320 ptmattach(int n) 321 { 322 extern const struct cdevsw pts_cdevsw, ptc_cdevsw; 323 /* find the major and minor of the pty devices */ 324 if ((pts_major = cdevsw_lookup_major(&pts_cdevsw)) == -1) 325 panic("ptmattach: Can't find pty slave in cdevsw"); 326 if ((ptc_major = cdevsw_lookup_major(&ptc_cdevsw)) == -1) 327 panic("ptmattach: Can't find pty master in cdevsw"); 328 #ifdef COMPAT_BSDPTY 329 ptm = &ptm_bsdpty; 330 #endif 331 } 332 333 static int 334 /*ARGSUSED*/ 335 ptmopen(dev_t dev, int flag, int mode, struct lwp *l) 336 { 337 int error; 338 int fd; 339 dev_t ttydev; 340 struct mount *mp; 341 342 switch(minor(dev)) { 343 case 0: /* /dev/ptmx */ 344 case 2: /* /emul/linux/dev/ptmx */ 345 if ((error = pty_getmp(l, &mp)) != 0) 346 return error; 347 if ((error = pty_alloc_master(l, &fd, &ttydev, mp)) != 0) 348 return error; 349 if (minor(dev) == 2) { 350 /* 351 * Linux ptyfs grants the pty right here. 352 * Handle this case here, instead of writing 353 * a new linux module. 354 */ 355 if ((error = pty_grant_slave(l, ttydev, mp)) != 0) { 356 file_t *fp = fd_getfile(fd); 357 if (fp != NULL) { 358 fd_close(fd); 359 } 360 return error; 361 } 362 } 363 curlwp->l_dupfd = fd; 364 return EMOVEFD; 365 case 1: /* /dev/ptm */ 366 return 0; 367 default: 368 return ENODEV; 369 } 370 } 371 372 static int 373 /*ARGSUSED*/ 374 ptmclose(dev_t dev, int flag, int mode, struct lwp *l) 375 { 376 377 return (0); 378 } 379 380 static int 381 /*ARGSUSED*/ 382 ptmioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) 383 { 384 int error; 385 dev_t newdev; 386 int cfd, sfd; 387 file_t *fp; 388 struct mount *mp; 389 390 error = 0; 391 switch (cmd) { 392 case TIOCPTMGET: 393 if ((error = pty_getmp(l, &mp)) != 0) 394 return error; 395 396 if ((error = pty_alloc_master(l, &cfd, &newdev, mp)) != 0) 397 return error; 398 399 if ((error = pty_grant_slave(l, newdev, mp)) != 0) 400 goto bad; 401 402 if ((error = pty_alloc_slave(l, &sfd, newdev, mp)) != 0) 403 goto bad; 404 405 /* now, put the indices and names into struct ptmget */ 406 if ((error = pty_fill_ptmget(l, newdev, cfd, sfd, data, mp)) != 0) 407 goto bad2; 408 return 0; 409 default: 410 #ifdef COMPAT_60 411 error = compat_60_ptmioctl(dev, cmd, data, flag, l); 412 if (error != EPASSTHROUGH) 413 return error; 414 #endif /* COMPAT_60 */ 415 DPRINTF(("ptmioctl EINVAL\n")); 416 return EINVAL; 417 } 418 bad2: 419 fp = fd_getfile(sfd); 420 if (fp != NULL) { 421 fd_close(sfd); 422 } 423 bad: 424 fp = fd_getfile(cfd); 425 if (fp != NULL) { 426 fd_close(cfd); 427 } 428 return error; 429 } 430 431 const struct cdevsw ptm_cdevsw = { 432 DEVSW_MODULE_INIT 433 .d_open = ptmopen, 434 .d_close = ptmclose, 435 .d_read = noread, 436 .d_write = nowrite, 437 .d_ioctl = ptmioctl, 438 .d_stop = nullstop, 439 .d_tty = notty, 440 .d_poll = nopoll, 441 .d_mmap = nommap, 442 .d_kqfilter = nokqfilter, 443 .d_discard = nodiscard, 444 .d_flag = D_TTY 445 }; 446 #endif 447
Indexes created Thu Oct 02 14:10:14 GMT 2025