| 1 | /* $NetBSD: tty_ptm.c,v 1.37 2015/08/24 22:50:32 pooka 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 2015/08/24 22:50:32 pooka 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 | |
| 57 | #include <miscfs/specfs/specdev.h> |
| 58 | |
| 59 | #ifdef COMPAT_60 |
| 60 | #include <compat/sys/ttycom.h> |
| 61 | #endif /* COMPAT_60 */ |
| 62 | |
| 63 | #include "ioconf.h" |
| 64 | |
| 65 | #ifdef DEBUG_PTM |
| 66 | #define DPRINTF(a) printf a |
| 67 | #else |
| 68 | #define DPRINTF(a) |
| 69 | #endif |
| 70 | |
| 71 | #ifdef NO_DEV_PTM |
| 72 | const struct cdevsw ptm_cdevsw = { |
| 73 | .d_open = noopen, |
| 74 | .d_close = noclose, |
| 75 | .d_read = noread, |
| 76 | .d_write = nowrite, |
| 77 | .d_ioctl = noioctl, |
| 78 | .d_stop = nostop, |
| 79 | .d_tty = notty, |
| 80 | .d_poll = nopoll, |
| 81 | .d_mmap = nommap, |
| 82 | .d_kqfilter = nokqfilter, |
| 83 | .d_discard = nodiscard, |
| 84 | .d_flag = D_TTY |
| 85 | }; |
| 86 | #else |
| 87 | |
| 88 | static struct ptm_pty *ptm; |
| 89 | int pts_major, ptc_major; |
| 90 | |
| 91 | static dev_t pty_getfree(void); |
| 92 | static int pty_alloc_master(struct lwp *, int *, dev_t *, struct mount *); |
| 93 | static int pty_alloc_slave(struct lwp *, int *, dev_t, struct mount *); |
| 94 | static int pty_vn_open(struct vnode *, struct lwp *); |
| 95 | |
| 96 | int |
| 97 | pty_getmp(struct lwp *l, struct mount **mpp) |
| 98 | { |
| 99 | if (ptm == NULL) |
| 100 | return EOPNOTSUPP; |
| 101 | |
| 102 | return (*ptm->getmp)(l, mpp); |
| 103 | } |
| 104 | |
| 105 | dev_t |
| 106 | pty_makedev(char ms, int minor) |
| 107 | { |
| 108 | return makedev(ms == 't' ? pts_major : ptc_major, minor); |
| 109 | } |
| 110 | |
| 111 | |
| 112 | static dev_t |
| 113 | pty_getfree(void) |
| 114 | { |
| 115 | extern kmutex_t pt_softc_mutex; |
| 116 | int i; |
| 117 | |
| 118 | mutex_enter(&pt_softc_mutex); |
| 119 | for (i = 0; i < npty; i++) { |
| 120 | if (pty_isfree(i, 0)) |
| 121 | break; |
| 122 | } |
| 123 | mutex_exit(&pt_softc_mutex); |
| 124 | return pty_makedev('t', i); |
| 125 | } |
| 126 | |
| 127 | /* |
| 128 | * Hacked up version of vn_open. We _only_ handle ptys and only open |
| 129 | * them with FREAD|FWRITE and never deal with creat or stuff like that. |
| 130 | * |
| 131 | * We need it because we have to fake up root credentials to open the pty. |
| 132 | */ |
| 133 | int |
| 134 | pty_vn_open(struct vnode *vp, struct lwp *l) |
| 135 | { |
| 136 | int error; |
| 137 | |
| 138 | if (vp->v_type != VCHR) { |
| 139 | vput(vp); |
| 140 | return EINVAL; |
| 141 | } |
| 142 | |
| 143 | error = VOP_OPEN(vp, FREAD|FWRITE, lwp0.l_cred); |
| 144 | |
| 145 | if (error) { |
| 146 | vput(vp); |
| 147 | return error; |
| 148 | } |
| 149 | |
| 150 | vp->v_writecount++; |
| 151 | |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | static int |
| 156 | pty_alloc_master(struct lwp *l, int *fd, dev_t *dev, struct mount *mp) |
| 157 | { |
| 158 | int error; |
| 159 | struct file *fp; |
| 160 | struct vnode *vp; |
| 161 | int md; |
| 162 | |
| 163 | if ((error = fd_allocfile(&fp, fd)) != 0) { |
| 164 | DPRINTF(("fd_allocfile %d\n" , error)); |
| 165 | return error; |
| 166 | } |
| 167 | retry: |
| 168 | /* Find and open a free master pty. */ |
| 169 | *dev = pty_getfree(); |
| 170 | md = minor(*dev); |
| 171 | if ((error = pty_check(md)) != 0) { |
| 172 | DPRINTF(("pty_check %d\n" , error)); |
| 173 | goto bad; |
| 174 | } |
| 175 | if (ptm == NULL) { |
| 176 | DPRINTF(("no ptm\n" )); |
| 177 | error = EOPNOTSUPP; |
| 178 | goto bad; |
| 179 | } |
| 180 | if ((error = (*ptm->allocvp)(mp, l, &vp, *dev, 'p')) != 0) { |
| 181 | DPRINTF(("pty_allocvp %d\n" , error)); |
| 182 | goto bad; |
| 183 | } |
| 184 | |
| 185 | if ((error = pty_vn_open(vp, l)) != 0) { |
| 186 | DPRINTF(("pty_vn_open %d\n" , error)); |
| 187 | /* |
| 188 | * Check if the master open failed because we lost |
| 189 | * the race to grab it. |
| 190 | */ |
| 191 | if (error != EIO) |
| 192 | goto bad; |
| 193 | error = !pty_isfree(md, 1); |
| 194 | DPRINTF(("pty_isfree %d\n" , error)); |
| 195 | if (error) |
| 196 | goto retry; |
| 197 | else |
| 198 | goto bad; |
| 199 | } |
| 200 | fp->f_flag = FREAD|FWRITE; |
| 201 | fp->f_type = DTYPE_VNODE; |
| 202 | fp->f_ops = &vnops; |
| 203 | fp->f_vnode = vp; |
| 204 | VOP_UNLOCK(vp); |
| 205 | fd_affix(curproc, fp, *fd); |
| 206 | return 0; |
| 207 | bad: |
| 208 | fd_abort(curproc, fp, *fd); |
| 209 | return error; |
| 210 | } |
| 211 | |
| 212 | int |
| 213 | pty_grant_slave(struct lwp *l, dev_t dev, struct mount *mp) |
| 214 | { |
| 215 | int error; |
| 216 | struct vnode *vp; |
| 217 | |
| 218 | /* |
| 219 | * Open the slave. |
| 220 | * namei -> setattr -> unlock -> revoke -> vrele -> |
| 221 | * namei -> open -> unlock |
| 222 | * Three stage rocket: |
| 223 | * 1. Change the owner and permissions on the slave. |
| 224 | * 2. Revoke all the users of the slave. |
| 225 | * 3. open the slave. |
| 226 | */ |
| 227 | if (ptm == NULL) |
| 228 | return EOPNOTSUPP; |
| 229 | if ((error = (*ptm->allocvp)(mp, l, &vp, dev, 't')) != 0) |
| 230 | return error; |
| 231 | |
| 232 | if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) { |
| 233 | struct vattr vattr; |
| 234 | (*ptm->getvattr)(mp, l, &vattr); |
| 235 | /* Do the VOP_SETATTR() as root. */ |
| 236 | error = VOP_SETATTR(vp, &vattr, lwp0.l_cred); |
| 237 | if (error) { |
| 238 | DPRINTF(("setattr %d\n" , error)); |
| 239 | VOP_UNLOCK(vp); |
| 240 | vrele(vp); |
| 241 | return error; |
| 242 | } |
| 243 | } |
| 244 | VOP_UNLOCK(vp); |
| 245 | VOP_REVOKE(vp, REVOKEALL); |
| 246 | |
| 247 | /* |
| 248 | * The vnode is useless after the revoke, we need to get it again. |
| 249 | */ |
| 250 | vrele(vp); |
| 251 | return 0; |
| 252 | } |
| 253 | |
| 254 | static int |
| 255 | pty_alloc_slave(struct lwp *l, int *fd, dev_t dev, struct mount *mp) |
| 256 | { |
| 257 | int error; |
| 258 | struct file *fp; |
| 259 | struct vnode *vp; |
| 260 | |
| 261 | /* Grab a filedescriptor for the slave */ |
| 262 | if ((error = fd_allocfile(&fp, fd)) != 0) { |
| 263 | DPRINTF(("fd_allocfile %d\n" , error)); |
| 264 | return error; |
| 265 | } |
| 266 | |
| 267 | if (ptm == NULL) { |
| 268 | error = EOPNOTSUPP; |
| 269 | goto bad; |
| 270 | } |
| 271 | |
| 272 | if ((error = (*ptm->allocvp)(mp, l, &vp, dev, 't')) != 0) |
| 273 | goto bad; |
| 274 | if ((error = pty_vn_open(vp, l)) != 0) |
| 275 | goto bad; |
| 276 | |
| 277 | fp->f_flag = FREAD|FWRITE; |
| 278 | fp->f_type = DTYPE_VNODE; |
| 279 | fp->f_ops = &vnops; |
| 280 | fp->f_vnode = vp; |
| 281 | VOP_UNLOCK(vp); |
| 282 | fd_affix(curproc, fp, *fd); |
| 283 | return 0; |
| 284 | bad: |
| 285 | fd_abort(curproc, fp, *fd); |
| 286 | return error; |
| 287 | } |
| 288 | |
| 289 | struct ptm_pty * |
| 290 | pty_sethandler(struct ptm_pty *nptm) |
| 291 | { |
| 292 | struct ptm_pty *optm = ptm; |
| 293 | ptm = nptm; |
| 294 | return optm; |
| 295 | } |
| 296 | |
| 297 | int |
| 298 | pty_fill_ptmget(struct lwp *l, dev_t dev, int cfd, int sfd, void *data, struct mount *mp) |
| 299 | { |
| 300 | struct ptmget *ptmg = data; |
| 301 | int error; |
| 302 | |
| 303 | if (ptm == NULL) |
| 304 | return EOPNOTSUPP; |
| 305 | |
| 306 | ptmg->cfd = cfd == -1 ? minor(dev) : cfd; |
| 307 | ptmg->sfd = sfd == -1 ? minor(dev) : sfd; |
| 308 | |
| 309 | error = (*ptm->makename)(mp, l, ptmg->cn, sizeof(ptmg->cn), dev, 'p'); |
| 310 | if (error) |
| 311 | return error; |
| 312 | |
| 313 | return (*ptm->makename)(mp, l, ptmg->sn, sizeof(ptmg->sn), dev, 't'); |
| 314 | } |
| 315 | |
| 316 | void |
| 317 | /*ARGSUSED*/ |
| 318 | ptmattach(int n) |
| 319 | { |
| 320 | extern const struct cdevsw pts_cdevsw, ptc_cdevsw; |
| 321 | /* find the major and minor of the pty devices */ |
| 322 | if ((pts_major = cdevsw_lookup_major(&pts_cdevsw)) == -1) |
| 323 | panic("ptmattach: Can't find pty slave in cdevsw" ); |
| 324 | if ((ptc_major = cdevsw_lookup_major(&ptc_cdevsw)) == -1) |
| 325 | panic("ptmattach: Can't find pty master in cdevsw" ); |
| 326 | #ifdef COMPAT_BSDPTY |
| 327 | ptm = &ptm_bsdpty; |
| 328 | #endif |
| 329 | } |
| 330 | |
| 331 | static int |
| 332 | /*ARGSUSED*/ |
| 333 | ptmopen(dev_t dev, int flag, int mode, struct lwp *l) |
| 334 | { |
| 335 | int error; |
| 336 | int fd; |
| 337 | dev_t ttydev; |
| 338 | struct mount *mp; |
| 339 | |
| 340 | switch(minor(dev)) { |
| 341 | case 0: /* /dev/ptmx */ |
| 342 | case 2: /* /emul/linux/dev/ptmx */ |
| 343 | if ((error = pty_getmp(l, &mp)) != 0) |
| 344 | return error; |
| 345 | if ((error = pty_alloc_master(l, &fd, &ttydev, mp)) != 0) |
| 346 | return error; |
| 347 | if (minor(dev) == 2) { |
| 348 | /* |
| 349 | * Linux ptyfs grants the pty right here. |
| 350 | * Handle this case here, instead of writing |
| 351 | * a new linux module. |
| 352 | */ |
| 353 | if ((error = pty_grant_slave(l, ttydev, mp)) != 0) { |
| 354 | file_t *fp = fd_getfile(fd); |
| 355 | if (fp != NULL) { |
| 356 | fd_close(fd); |
| 357 | } |
| 358 | return error; |
| 359 | } |
| 360 | } |
| 361 | curlwp->l_dupfd = fd; |
| 362 | return EMOVEFD; |
| 363 | case 1: /* /dev/ptm */ |
| 364 | return 0; |
| 365 | default: |
| 366 | return ENODEV; |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | static int |
| 371 | /*ARGSUSED*/ |
| 372 | ptmclose(dev_t dev, int flag, int mode, struct lwp *l) |
| 373 | { |
| 374 | |
| 375 | return (0); |
| 376 | } |
| 377 | |
| 378 | static int |
| 379 | /*ARGSUSED*/ |
| 380 | ptmioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) |
| 381 | { |
| 382 | int error; |
| 383 | dev_t newdev; |
| 384 | int cfd, sfd; |
| 385 | file_t *fp; |
| 386 | struct mount *mp; |
| 387 | |
| 388 | error = 0; |
| 389 | switch (cmd) { |
| 390 | case TIOCPTMGET: |
| 391 | if ((error = pty_getmp(l, &mp)) != 0) |
| 392 | return error; |
| 393 | |
| 394 | if ((error = pty_alloc_master(l, &cfd, &newdev, mp)) != 0) |
| 395 | return error; |
| 396 | |
| 397 | if ((error = pty_grant_slave(l, newdev, mp)) != 0) |
| 398 | goto bad; |
| 399 | |
| 400 | if ((error = pty_alloc_slave(l, &sfd, newdev, mp)) != 0) |
| 401 | goto bad; |
| 402 | |
| 403 | /* now, put the indices and names into struct ptmget */ |
| 404 | if ((error = pty_fill_ptmget(l, newdev, cfd, sfd, data, mp)) != 0) |
| 405 | goto bad2; |
| 406 | return 0; |
| 407 | default: |
| 408 | #ifdef COMPAT_60 |
| 409 | error = compat_60_ptmioctl(dev, cmd, data, flag, l); |
| 410 | if (error != EPASSTHROUGH) |
| 411 | return error; |
| 412 | #endif /* COMPAT_60 */ |
| 413 | DPRINTF(("ptmioctl EINVAL\n" )); |
| 414 | return EINVAL; |
| 415 | } |
| 416 | bad2: |
| 417 | fp = fd_getfile(sfd); |
| 418 | if (fp != NULL) { |
| 419 | fd_close(sfd); |
| 420 | } |
| 421 | bad: |
| 422 | fp = fd_getfile(cfd); |
| 423 | if (fp != NULL) { |
| 424 | fd_close(cfd); |
| 425 | } |
| 426 | return error; |
| 427 | } |
| 428 | |
| 429 | const struct cdevsw ptm_cdevsw = { |
| 430 | .d_open = ptmopen, |
| 431 | .d_close = ptmclose, |
| 432 | .d_read = noread, |
| 433 | .d_write = nowrite, |
| 434 | .d_ioctl = ptmioctl, |
| 435 | .d_stop = nullstop, |
| 436 | .d_tty = notty, |
| 437 | .d_poll = nopoll, |
| 438 | .d_mmap = nommap, |
| 439 | .d_kqfilter = nokqfilter, |
| 440 | .d_discard = nodiscard, |
| 441 | .d_flag = D_TTY |
| 442 | }; |
| 443 | #endif |
| 444 | |