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, devname, UIO_SYSSPACE, NLC_FOLLOW, 73 cred, &synth_mp->mnt_ncmountpt, 74 &synth_mp->mnt_ncmountpt); 75 76 if (error) { 77 panic("synth: nlookup_init_root failed with %d", error); 78 /* NOTREACHED */ 79 } 80 81 error = nlookup(&nd); 82 if (error == 0) { 83 if (nd.nl_nch.ncp->nc_vp == NULL) { 84 kprintf("synth: nc_vp == NULL\n"); 85 return (NULL); 86 } 87 nch = nd.nl_nch; 88 cache_zero(&nd.nl_nch); 89 } 90 91 nlookup_done(&nd); 92 if (error) { 93 if (error != ENOENT) { /* Don't bother warning about ENOENT */ 94 kprintf("synth: nlookup of %s failed with %d\n", 95 devname, error); 96 } 97 return (NULL); 98 } 99 100 vp = nch.ncp->nc_vp; 101 /* A VX locked & refd vnode must be returned. */ 102 error = vget(vp, LK_EXCLUSIVE); 103 cache_unlock(&nch); 104 105 if (error) { 106 kprintf("synth: could not vget vnode\n"); 107 return (NULL); 108 } 109 110 return (vp); 111 } 112 113 static void 114 synthinit(void *arg __unused) 115 { 116 int error; 117 118 if ((error = vfs_rootmountalloc("devfs", "dummy", &synth_mp))) { 119 panic("synth: vfs_rootmountalloc failed with %d", error); 120 /* NOTREACHED */ 121 } 122 if ((error = VFS_MOUNT(synth_mp, NULL, NULL, proc0.p_ucred))) { 123 panic("synth: vfs_mount failed with %d", error); 124 /* NOTREACHED */ 125 } 126 if ((error = VFS_ROOT(synth_mp, &synth_vp))) { 127 panic("synth: vfs_root failed with %d", error); 128 /* NOTREACHED */ 129 } 130 cache_allocroot(&synth_mp->mnt_ncmountpt, synth_mp, synth_vp); 131 cache_unlock(&synth_mp->mnt_ncmountpt); /* leave ref intact */ 132 vput(synth_vp); 133 134 synth_inited = 1; 135 } 136 137 SYSINIT(synthinit, SI_SUB_VFS, SI_ORDER_ANY, synthinit, NULL); 138