1 /* 2 * Copyright (c) 2010 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Alex Hornung <ahornung (at) gmail.com> 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 * 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 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/kernel.h> 38 #include <sys/vnode.h> 39 #include <sys/lock.h> 40 #include <sys/disk.h> 41 #include <sys/mount.h> 42 #include <sys/namecache.h> 43 #include <sys/nlookup.h> 44 #include <sys/proc.h> 45 #include <sys/thread2.h> 46 #include <sys/devfs.h> 47 48 struct mount *synth_mp; 49 struct vnode *synth_vp; 50 static int synth_inited = 0; 51 static int synth_synced = 0; 52 53 struct vnode * 54 getsynthvnode(const char *devname) 55 { 56 struct vnode *vp; 57 struct nchandle nch; 58 struct nlookupdata nd; 59 struct ucred *cred = proc0.p_ucred; 60 int error; 61 62 KKASSERT(synth_inited != 0); 63 KKASSERT(synth_mp != NULL); 64 KKASSERT(synth_mp->mnt_ncmountpt.mount != NULL); 65 66 /* Sync devfs/disks twice to make sure all devices are around */ 67 if (synth_synced < 2) { 68 sync_devs(); 69 ++synth_synced; 70 } 71 72 error = nlookup_init_root(&nd, 73 devname, UIO_SYSSPACE, NLC_FOLLOW, 74 cred, &synth_mp->mnt_ncmountpt, 75 &synth_mp->mnt_ncmountpt); 76 77 if (error) { 78 panic("synth: nlookup_init_root failed with %d", error); 79 /* NOTREACHED */ 80 } 81 82 error = nlookup(&nd); 83 if (error == 0) { 84 if (nd.nl_nch.ncp->nc_vp == NULL) { 85 kprintf("synth: nc_vp == NULL\n"); 86 return (NULL); 87 } 88 nch = nd.nl_nch; 89 cache_zero(&nd.nl_nch); 90 } 91 92 nlookup_done(&nd); 93 if (error) { 94 if (error != ENOENT) { /* Don't bother warning about ENOENT */ 95 kprintf("synth: nlookup of %s failed with %d\n", 96 devname, error); 97 } 98 return (NULL); 99 } 100 101 vp = nch.ncp->nc_vp; 102 /* A VX locked & refd vnode must be returned. */ 103 error = vget(vp, LK_EXCLUSIVE); 104 cache_unlock(&nch); 105 106 if (error) { 107 kprintf("synth: could not vget vnode\n"); 108 return (NULL); 109 } 110 111 return (vp); 112 } 113 114 static void 115 synthinit(void *arg __unused) 116 { 117 int error; 118 119 if ((error = vfs_rootmountalloc("devfs", "dummy", &synth_mp))) { 120 panic("synth: vfs_rootmountalloc failed with %d", error); 121 /* NOTREACHED */ 122 } 123 if ((error = VFS_MOUNT(synth_mp, NULL, NULL, proc0.p_ucred))) { 124 panic("synth: vfs_mount failed with %d", error); 125 /* NOTREACHED */ 126 } 127 if ((error = VFS_ROOT(synth_mp, &synth_vp))) { 128 panic("synth: vfs_root failed with %d", error); 129 /* NOTREACHED */ 130 } 131 cache_allocroot(&synth_mp->mnt_ncmountpt, synth_mp, synth_vp); 132 cache_unlock(&synth_mp->mnt_ncmountpt); /* leave ref intact */ 133 vput(synth_vp); 134 135 synth_inited = 1; 136 } 137 138 SYSINIT(synthinit, SI_SUB_VFS, SI_ORDER_ANY, synthinit, NULL); 139