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/conf.h> 35 #include <sys/eventhandler.h> 36 #include <sys/fcntl.h> 37 #include <sys/kernel.h> 38 #include <sys/module.h> 39 #include <sys/proc.h> 40 #include <sys/sysctl.h> 41 #include <sys/syslog.h> 42 #include <sys/systm.h> 43 #include <sys/tty.h> 44 45 /* 46 * This driver implements a BSD-style compatibility naming scheme for 47 * the pts(4) driver. We just call into pts(4) to create the actual PTY. 48 * To make sure we don't use the same PTY multiple times, we abuse 49 * si_drv1 inside the cdev to mark whether the PTY is in use. 50 * 51 * It also implements a /dev/ptmx device node, which is useful for Linux 52 * binary emulation. 53 */ 54 55 static unsigned pty_warningcnt = 1; 56 SYSCTL_UINT(_kern, OID_AUTO, tty_pty_warningcnt, CTLFLAG_RW, 57 &pty_warningcnt, 0, 58 "Warnings that will be triggered upon legacy PTY allocation"); 59 60 static int 61 ptydev_fdopen(struct cdev *dev, int fflags, struct thread *td, struct file *fp) 62 { 63 int error; 64 char name[6]; /* "ttyXX" */ 65 66 if (!atomic_cmpset_ptr((uintptr_t *)&dev->si_drv1, 0, 1)) 67 return (EBUSY); 68 69 /* Generate device name and create PTY. */ 70 strlcpy(name, devtoname(dev), sizeof(name)); 71 name[0] = 't'; 72 73 error = pts_alloc_external(fflags & (FREAD|FWRITE), td, fp, dev, name); 74 if (error != 0) { 75 destroy_dev_sched(dev); 76 return (error); 77 } 78 79 /* Raise a warning when a legacy PTY has been allocated. */ 80 counted_warning(&pty_warningcnt, "is using legacy pty devices"); 81 82 return (0); 83 } 84 85 static struct cdevsw ptydev_cdevsw = { 86 .d_version = D_VERSION, 87 .d_fdopen = ptydev_fdopen, 88 .d_name = "ptydev", 89 }; 90 91 static void 92 pty_clone(void *arg, struct ucred *cr, char *name, int namelen, 93 struct cdev **dev) 94 { 95 struct make_dev_args mda; 96 int error; 97 98 /* Cloning is already satisfied. */ 99 if (*dev != NULL) 100 return; 101 102 /* Only catch /dev/ptyXX. */ 103 if (namelen != 5 || bcmp(name, "pty", 3) != 0) 104 return; 105 106 /* Only catch /dev/pty[l-sL-S]X. */ 107 if (!(name[3] >= 'l' && name[3] <= 's') && 108 !(name[3] >= 'L' && name[3] <= 'S')) 109 return; 110 111 /* Only catch /dev/pty[l-sL-S][0-9a-v]. */ 112 if (!(name[4] >= '0' && name[4] <= '9') && 113 !(name[4] >= 'a' && name[4] <= 'v')) 114 return; 115 116 /* Create the controller device node. */ 117 make_dev_args_init(&mda); 118 mda.mda_flags = MAKEDEV_CHECKNAME | MAKEDEV_REF; 119 mda.mda_devsw = &ptydev_cdevsw; 120 mda.mda_uid = UID_ROOT; 121 mda.mda_gid = GID_WHEEL; 122 mda.mda_mode = 0666; 123 error = make_dev_s(&mda, dev, "%s", name); 124 if (error != 0) 125 *dev = NULL; 126 } 127 128 static int 129 ptmx_fdopen(struct cdev *dev __unused, int fflags, struct thread *td, 130 struct file *fp) 131 { 132 133 return (pts_alloc(fflags & (FREAD|FWRITE), td, fp)); 134 } 135 136 static struct cdevsw ptmx_cdevsw = { 137 .d_version = D_VERSION, 138 .d_fdopen = ptmx_fdopen, 139 .d_name = "ptmx", 140 }; 141 142 static int 143 pty_modevent(module_t mod, int type, void *data) 144 { 145 146 switch(type) { 147 case MOD_LOAD: 148 EVENTHANDLER_REGISTER(dev_clone, pty_clone, 0, 1000); 149 make_dev_credf(MAKEDEV_ETERNAL_KLD, &ptmx_cdevsw, 0, NULL, 150 UID_ROOT, GID_WHEEL, 0666, "ptmx"); 151 break; 152 case MOD_SHUTDOWN: 153 break; 154 case MOD_UNLOAD: 155 /* XXX: No unloading support yet. */ 156 return (EBUSY); 157 default: 158 return (EOPNOTSUPP); 159 } 160 161 return (0); 162 } 163 164 DEV_MODULE(pty, pty_modevent, NULL); 165