tty_ptm.c revision 1.10
1 /* $NetBSD: tty_ptm.c,v 1.10 2006/07/17 14:49:16 ad 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 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the NetBSD 18 * Foundation, Inc. and its contributors. 19 * 4. Neither the name of The NetBSD Foundation nor the names of its 20 * contributors may be used to endorse or promote products derived 21 * from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 27 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: tty_ptm.c,v 1.10 2006/07/17 14:49:16 ad Exp $"); 38 39 #include "opt_ptm.h" 40 41 /* pty multiplexor driver /dev/ptm{,x} */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/ioctl.h> 46 #include <sys/proc.h> 47 #include <sys/tty.h> 48 #include <sys/stat.h> 49 #include <sys/file.h> 50 #include <sys/uio.h> 51 #include <sys/kernel.h> 52 #include <sys/vnode.h> 53 #include <sys/namei.h> 54 #include <sys/signalvar.h> 55 #include <sys/uio.h> 56 #include <sys/filedesc.h> 57 #include <sys/conf.h> 58 #include <sys/poll.h> 59 #include <sys/malloc.h> 60 #include <sys/pty.h> 61 #include <sys/kauth.h> 62 63 #ifdef DEBUG_PTM 64 #define DPRINTF(a) printf a 65 #else 66 #define DPRINTF(a) 67 #endif 68 69 #ifdef NO_DEV_PTM 70 const struct cdevsw ptm_cdevsw = { 71 noopen, noclose, noread, nowrite, noioctl, 72 nostop, notty, nopoll, nommap, nokqfilter, D_TTY 73 }; 74 #else 75 76 static struct ptm_pty *ptm; 77 int pts_major, ptc_major; 78 79 static dev_t pty_getfree(void); 80 static int pty_alloc_master(struct lwp *, int *, dev_t *); 81 static int pty_alloc_slave(struct lwp *, int *, dev_t); 82 83 void ptmattach(int); 84 85 dev_t 86 pty_makedev(char ms, int minor) 87 { 88 return makedev(ms == 't' ? pts_major : ptc_major, minor); 89 } 90 91 92 static dev_t 93 pty_getfree(void) 94 { 95 extern struct simplelock pt_softc_mutex; 96 int i; 97 98 simple_lock(&pt_softc_mutex); 99 for (i = 0; i < npty; i++) { 100 if (pty_isfree(i, 0)) 101 break; 102 } 103 simple_unlock(&pt_softc_mutex); 104 return pty_makedev('t', i); 105 } 106 107 /* 108 * Hacked up version of vn_open. We _only_ handle ptys and only open 109 * them with FREAD|FWRITE and never deal with creat or stuff like that. 110 * 111 * We need it because we have to fake up root credentials to open the pty. 112 */ 113 int 114 pty_vn_open(struct vnode *vp, struct lwp *l) 115 { 116 int error; 117 118 if (vp->v_type != VCHR) { 119 vput(vp); 120 return EINVAL; 121 } 122 123 error = VOP_OPEN(vp, FREAD|FWRITE, proc0.p_cred, l); 124 125 if (error) { 126 vput(vp); 127 return error; 128 } 129 130 vp->v_writecount++; 131 132 return 0; 133 } 134 135 static int 136 pty_alloc_master(struct lwp *l, int *fd, dev_t *dev) 137 { 138 int error; 139 struct file *fp; 140 struct vnode *vp; 141 struct proc *p = l->l_proc; 142 int md; 143 144 if ((error = falloc(p, &fp, fd)) != 0) { 145 DPRINTF(("falloc %d\n", error)); 146 return error; 147 } 148 retry: 149 /* Find and open a free master pty. */ 150 *dev = pty_getfree(); 151 md = minor(*dev); 152 if ((error = pty_check(md)) != 0) { 153 DPRINTF(("pty_check %d\n", error)); 154 goto bad; 155 } 156 if (ptm == NULL) { 157 error = EOPNOTSUPP; 158 goto bad; 159 } 160 if ((error = (*ptm->allocvp)(ptm, l, &vp, *dev, 'p')) != 0) 161 goto bad; 162 163 if ((error = pty_vn_open(vp, l)) != 0) { 164 /* 165 * Check if the master open failed because we lost 166 * the race to grab it. 167 */ 168 if (error != EIO) 169 goto bad; 170 error = !pty_isfree(md, 1); 171 if (error) 172 goto retry; 173 else 174 goto bad; 175 } 176 fp->f_flag = FREAD|FWRITE; 177 fp->f_type = DTYPE_VNODE; 178 fp->f_ops = &vnops; 179 fp->f_data = vp; 180 VOP_UNLOCK(vp, 0); 181 FILE_SET_MATURE(fp); 182 FILE_UNUSE(fp, l); 183 return 0; 184 bad: 185 FILE_UNUSE(fp, l); 186 fdremove(p->p_fd, *fd); 187 ffree(fp); 188 return error; 189 } 190 191 int 192 pty_grant_slave(struct lwp *l, dev_t dev) 193 { 194 int error; 195 struct vnode *vp; 196 197 /* 198 * Open the slave. 199 * namei -> setattr -> unlock -> revoke -> vrele -> 200 * namei -> open -> unlock 201 * Three stage rocket: 202 * 1. Change the owner and permissions on the slave. 203 * 2. Revoke all the users of the slave. 204 * 3. open the slave. 205 */ 206 if (ptm == NULL) 207 return EOPNOTSUPP; 208 209 if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0) 210 return error; 211 212 if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0) { 213 struct vattr vattr; 214 (*ptm->getvattr)(ptm, l->l_proc, &vattr); 215 /* Do the VOP_SETATTR() as root. */ 216 error = VOP_SETATTR(vp, &vattr, proc0.p_cred, l); 217 if (error) { 218 DPRINTF(("setattr %d\n", error)); 219 VOP_UNLOCK(vp, 0); 220 vrele(vp); 221 return error; 222 } 223 } 224 VOP_UNLOCK(vp, 0); 225 if (vp->v_usecount > 1 || 226 (vp->v_flag & (VALIASED | VLAYER))) 227 VOP_REVOKE(vp, REVOKEALL); 228 229 /* 230 * The vnode is useless after the revoke, we need to get it again. 231 */ 232 vrele(vp); 233 return 0; 234 } 235 236 static int 237 pty_alloc_slave(struct lwp *l, int *fd, dev_t dev) 238 { 239 int error; 240 struct file *fp; 241 struct vnode *vp; 242 struct proc *p = l->l_proc; 243 244 /* Grab a filedescriptor for the slave */ 245 if ((error = falloc(p, &fp, fd)) != 0) { 246 DPRINTF(("falloc %d\n", error)); 247 return error; 248 } 249 250 if (ptm == NULL) { 251 error = EOPNOTSUPP; 252 goto bad; 253 } 254 255 if ((error = (*ptm->allocvp)(ptm, l, &vp, dev, 't')) != 0) 256 goto bad; 257 if ((error = pty_vn_open(vp, l)) != 0) 258 goto bad; 259 260 fp->f_flag = FREAD|FWRITE; 261 fp->f_type = DTYPE_VNODE; 262 fp->f_ops = &vnops; 263 fp->f_data = vp; 264 VOP_UNLOCK(vp, 0); 265 FILE_SET_MATURE(fp); 266 FILE_UNUSE(fp, l); 267 return 0; 268 bad: 269 FILE_UNUSE(fp, l); 270 fdremove(p->p_fd, *fd); 271 ffree(fp); 272 return error; 273 } 274 275 struct ptm_pty * 276 pty_sethandler(struct ptm_pty *nptm) 277 { 278 struct ptm_pty *optm = ptm; 279 ptm = nptm; 280 return optm; 281 } 282 283 int 284 pty_fill_ptmget(struct lwp *l, dev_t dev, int cfd, int sfd, void *data) 285 { 286 struct ptmget *ptmg = data; 287 int error; 288 289 if (ptm == NULL) 290 return EOPNOTSUPP; 291 292 ptmg->cfd = cfd == -1 ? minor(dev) : cfd; 293 ptmg->sfd = sfd == -1 ? minor(dev) : sfd; 294 295 error = (*ptm->makename)(ptm, l, ptmg->cn, sizeof(ptmg->cn), dev, 'p'); 296 if (error) 297 return error; 298 299 return (*ptm->makename)(ptm, l, ptmg->sn, sizeof(ptmg->sn), dev, 't'); 300 } 301 302 void 303 /*ARGSUSED*/ 304 ptmattach(int n) 305 { 306 extern const struct cdevsw pts_cdevsw, ptc_cdevsw; 307 /* find the major and minor of the pty devices */ 308 if ((pts_major = cdevsw_lookup_major(&pts_cdevsw)) == -1) 309 panic("ptmattach: Can't find pty slave in cdevsw"); 310 if ((ptc_major = cdevsw_lookup_major(&ptc_cdevsw)) == -1) 311 panic("ptmattach: Can't find pty master in cdevsw"); 312 #ifdef COMPAT_BSDPTY 313 ptm = &ptm_bsdpty; 314 #endif 315 } 316 317 static int 318 /*ARGSUSED*/ 319 ptmopen(dev_t dev, int flag, int mode, struct lwp *l) 320 { 321 int error; 322 int fd; 323 324 switch(minor(dev)) { 325 case 0: /* /dev/ptmx */ 326 if ((error = pty_alloc_master(l, &fd, &dev)) != 0) 327 return error; 328 curlwp->l_dupfd = fd; 329 return EMOVEFD; 330 case 1: /* /dev/ptm */ 331 return 0; 332 default: 333 return ENODEV; 334 } 335 } 336 337 static int 338 /*ARGSUSED*/ 339 ptmclose(dev_t dev, int flag, int mode, struct lwp *l) 340 { 341 return (0); 342 } 343 344 static int 345 /*ARGSUSED*/ 346 ptmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct lwp *l) 347 { 348 int error; 349 dev_t newdev; 350 int cfd, sfd; 351 struct file *fp; 352 struct proc *p = l->l_proc; 353 354 error = 0; 355 switch (cmd) { 356 case TIOCPTMGET: 357 if ((error = pty_alloc_master(l, &cfd, &newdev)) != 0) 358 return error; 359 360 if ((error = pty_grant_slave(l, newdev)) != 0) 361 goto bad; 362 363 if ((error = pty_alloc_slave(l, &sfd, newdev)) != 0) 364 goto bad; 365 366 /* now, put the indices and names into struct ptmget */ 367 return pty_fill_ptmget(l, newdev, cfd, sfd, data); 368 default: 369 DPRINTF(("ptmioctl EINVAL\n")); 370 return EINVAL; 371 } 372 bad: 373 fp = fd_getfile(p->p_fd, cfd); 374 fdremove(p->p_fd, cfd); 375 ffree(fp); 376 return error; 377 } 378 379 const struct cdevsw ptm_cdevsw = { 380 ptmopen, ptmclose, noread, nowrite, ptmioctl, 381 nullstop, notty, nopoll, nommap, nokqfilter, D_TTY 382 }; 383 #endif 384
Indexes created Thu Sep 25 16:09:42 GMT 2025