428 lines
12 KiB
C
428 lines
12 KiB
C
/* $NetBSD: ptyfs_subr.c,v 1.22 2010/11/19 06:44:41 dholland Exp $ */
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/*
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* Copyright (c) 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ptyfs_subr.c 8.6 (Berkeley) 5/14/95
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*/
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/*
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* Copyright (c) 1994 Christopher G. Demetriou. All rights reserved.
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* Copyright (c) 1993 Jan-Simon Pendry
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*
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* This code is derived from software contributed to Berkeley by
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* Jan-Simon Pendry.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)procfs_subr.c 8.6 (Berkeley) 5/14/95
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: ptyfs_subr.c,v 1.22 2010/11/19 06:44:41 dholland Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/vnode.h>
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#include <sys/stat.h>
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#include <sys/malloc.h>
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#include <sys/file.h>
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#include <sys/namei.h>
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#include <sys/filedesc.h>
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#include <sys/select.h>
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#include <sys/tty.h>
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#include <sys/pty.h>
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#include <sys/kauth.h>
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#include <sys/lwp.h>
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#include <fs/ptyfs/ptyfs.h>
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#include <miscfs/specfs/specdev.h>
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static kmutex_t ptyfs_hashlock;
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static LIST_HEAD(ptyfs_hashhead, ptyfsnode) *ptyfs_used_tbl, *ptyfs_free_tbl;
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static u_long ptyfs_used_mask, ptyfs_free_mask; /* size of hash table - 1 */
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static kmutex_t ptyfs_used_slock, ptyfs_free_slock;
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static void ptyfs_getinfo(struct ptyfsnode *, struct lwp *);
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static void ptyfs_hashins(struct ptyfsnode *);
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static void ptyfs_hashrem(struct ptyfsnode *);
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static struct vnode *ptyfs_used_get(ptyfstype, int, struct mount *, int);
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static struct ptyfsnode *ptyfs_free_get(ptyfstype, int, struct lwp *);
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static void ptyfs_rehash(kmutex_t *, struct ptyfs_hashhead **,
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u_long *);
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#define PTYHASH(type, pty, mask) (PTYFS_FILENO(type, pty) % (mask + 1))
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static void
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ptyfs_getinfo(struct ptyfsnode *ptyfs, struct lwp *l)
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{
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extern struct ptm_pty *ptyfs_save_ptm, ptm_ptyfspty;
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if (ptyfs->ptyfs_type == PTYFSroot) {
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ptyfs->ptyfs_mode = S_IRUSR|S_IXUSR|S_IRGRP|S_IXGRP|
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S_IROTH|S_IXOTH;
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goto out;
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} else
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ptyfs->ptyfs_mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|
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S_IROTH|S_IWOTH;
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if (ptyfs_save_ptm != NULL && ptyfs_save_ptm != &ptm_ptyfspty) {
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int error;
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struct pathbuf *pb;
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struct nameidata nd;
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char ttyname[64];
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kauth_cred_t cred;
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struct vattr va;
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/*
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* We support traditional ptys, so we copy the info
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* from the inode
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*/
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if ((error = (*ptyfs_save_ptm->makename)(
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ptyfs_save_ptm, l, ttyname, sizeof(ttyname),
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ptyfs->ptyfs_pty, ptyfs->ptyfs_type == PTYFSpts ? 't'
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: 'p')) != 0)
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goto out;
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pb = pathbuf_create(ttyname);
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if (pb == NULL) {
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error = ENOMEM;
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goto out;
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}
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NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, pb);
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if ((error = namei(&nd)) != 0) {
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pathbuf_destroy(pb);
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goto out;
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}
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cred = kauth_cred_alloc();
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error = VOP_GETATTR(nd.ni_vp, &va, cred);
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kauth_cred_free(cred);
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VOP_UNLOCK(nd.ni_vp);
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vrele(nd.ni_vp);
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pathbuf_destroy(pb);
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if (error)
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goto out;
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ptyfs->ptyfs_uid = va.va_uid;
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ptyfs->ptyfs_gid = va.va_gid;
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ptyfs->ptyfs_mode = va.va_mode;
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ptyfs->ptyfs_flags = va.va_flags;
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ptyfs->ptyfs_birthtime = va.va_birthtime;
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ptyfs->ptyfs_ctime = va.va_ctime;
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ptyfs->ptyfs_mtime = va.va_mtime;
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ptyfs->ptyfs_atime = va.va_atime;
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return;
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}
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out:
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ptyfs->ptyfs_uid = ptyfs->ptyfs_gid = 0;
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ptyfs->ptyfs_flags |= PTYFS_CHANGE;
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PTYFS_ITIMES(ptyfs, NULL, NULL, NULL);
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ptyfs->ptyfs_birthtime = ptyfs->ptyfs_mtime =
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ptyfs->ptyfs_atime = ptyfs->ptyfs_ctime;
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ptyfs->ptyfs_flags = 0;
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}
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/*
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* allocate a ptyfsnode/vnode pair. the vnode is
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* referenced, and locked.
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*
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* the pid, ptyfs_type, and mount point uniquely
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* identify a ptyfsnode. the mount point is needed
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* because someone might mount this filesystem
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* twice.
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*
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* all ptyfsnodes are maintained on a singly-linked
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* list. new nodes are only allocated when they cannot
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* be found on this list. entries on the list are
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* removed when the vfs reclaim entry is called.
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*
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* a single lock is kept for the entire list. this is
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* needed because the getnewvnode() function can block
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* waiting for a vnode to become free, in which case there
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* may be more than one ptyess trying to get the same
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* vnode. this lock is only taken if we are going to
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* call getnewvnode, since the kernel itself is single-threaded.
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*
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* if an entry is found on the list, then call vget() to
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* take a reference. this is done because there may be
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* zero references to it and so it needs to removed from
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* the vnode free list.
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*/
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int
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ptyfs_allocvp(struct mount *mp, struct vnode **vpp, ptyfstype type, int pty,
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struct lwp *l)
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{
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struct ptyfsnode *ptyfs;
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struct vnode *vp;
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int error;
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retry:
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if ((*vpp = ptyfs_used_get(type, pty, mp, LK_EXCLUSIVE)) != NULL)
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return 0;
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if ((error = getnewvnode(VT_PTYFS, mp, ptyfs_vnodeop_p, &vp)) != 0) {
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*vpp = NULL;
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return error;
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}
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mutex_enter(&ptyfs_hashlock);
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if (ptyfs_used_get(type, pty, mp, 0) != NULL) {
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mutex_exit(&ptyfs_hashlock);
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ungetnewvnode(vp);
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goto retry;
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}
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vp->v_data = ptyfs = ptyfs_free_get(type, pty, l);
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ptyfs->ptyfs_vnode = vp;
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switch (type) {
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case PTYFSroot: /* /pts = dr-xr-xr-x */
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vp->v_type = VDIR;
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vp->v_vflag = VV_ROOT;
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break;
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case PTYFSpts: /* /pts/N = cxxxxxxxxx */
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case PTYFSptc: /* controlling side = cxxxxxxxxx */
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vp->v_type = VCHR;
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spec_node_init(vp, PTYFS_MAKEDEV(ptyfs));
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break;
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default:
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panic("ptyfs_allocvp");
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}
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ptyfs_hashins(ptyfs);
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uvm_vnp_setsize(vp, 0);
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mutex_exit(&ptyfs_hashlock);
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*vpp = vp;
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return 0;
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}
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int
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ptyfs_freevp(struct vnode *vp)
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{
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struct ptyfsnode *ptyfs = VTOPTYFS(vp);
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ptyfs_hashrem(ptyfs);
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vp->v_data = NULL;
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return 0;
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}
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/*
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* Initialize ptyfsnode hash table.
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*/
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void
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ptyfs_hashinit(void)
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{
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ptyfs_used_tbl = hashinit(desiredvnodes / 4, HASH_LIST, true,
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&ptyfs_used_mask);
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ptyfs_free_tbl = hashinit(desiredvnodes / 4, HASH_LIST, true,
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&ptyfs_free_mask);
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mutex_init(&ptyfs_hashlock, MUTEX_DEFAULT, IPL_NONE);
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mutex_init(&ptyfs_used_slock, MUTEX_DEFAULT, IPL_NONE);
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mutex_init(&ptyfs_free_slock, MUTEX_DEFAULT, IPL_NONE);
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}
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void
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ptyfs_hashreinit(void)
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{
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ptyfs_rehash(&ptyfs_used_slock, &ptyfs_used_tbl, &ptyfs_used_mask);
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ptyfs_rehash(&ptyfs_free_slock, &ptyfs_free_tbl, &ptyfs_free_mask);
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}
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static void
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ptyfs_rehash(kmutex_t *hlock, struct ptyfs_hashhead **hhead,
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u_long *hmask)
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{
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struct ptyfsnode *pp;
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struct ptyfs_hashhead *oldhash, *hash;
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u_long i, oldmask, mask, val;
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hash = hashinit(desiredvnodes / 4, HASH_LIST, true, &mask);
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mutex_enter(hlock);
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oldhash = *hhead;
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oldmask = *hmask;
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*hhead = hash;
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*hmask = mask;
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for (i = 0; i <= oldmask; i++) {
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while ((pp = LIST_FIRST(&oldhash[i])) != NULL) {
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LIST_REMOVE(pp, ptyfs_hash);
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val = PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
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ptyfs_used_mask);
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LIST_INSERT_HEAD(&hash[val], pp, ptyfs_hash);
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}
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}
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mutex_exit(hlock);
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hashdone(oldhash, HASH_LIST, oldmask);
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}
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/*
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* Free ptyfsnode hash table.
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*/
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void
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ptyfs_hashdone(void)
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{
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mutex_destroy(&ptyfs_hashlock);
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mutex_destroy(&ptyfs_used_slock);
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mutex_destroy(&ptyfs_free_slock);
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hashdone(ptyfs_used_tbl, HASH_LIST, ptyfs_used_mask);
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hashdone(ptyfs_free_tbl, HASH_LIST, ptyfs_free_mask);
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}
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/*
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* Get a ptyfsnode from the free table, or allocate one.
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* Removes the node from the free table.
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*/
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struct ptyfsnode *
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ptyfs_free_get(ptyfstype type, int pty, struct lwp *l)
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{
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struct ptyfs_hashhead *ppp;
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struct ptyfsnode *pp;
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mutex_enter(&ptyfs_free_slock);
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ppp = &ptyfs_free_tbl[PTYHASH(type, pty, ptyfs_free_mask)];
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LIST_FOREACH(pp, ppp, ptyfs_hash) {
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if (pty == pp->ptyfs_pty && pp->ptyfs_type == type) {
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LIST_REMOVE(pp, ptyfs_hash);
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mutex_exit(&ptyfs_free_slock);
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return pp;
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}
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}
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mutex_exit(&ptyfs_free_slock);
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pp = malloc(sizeof(struct ptyfsnode), M_TEMP, M_WAITOK);
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pp->ptyfs_pty = pty;
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pp->ptyfs_type = type;
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pp->ptyfs_fileno = PTYFS_FILENO(pty, type);
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ptyfs_getinfo(pp, l);
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return pp;
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}
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struct vnode *
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ptyfs_used_get(ptyfstype type, int pty, struct mount *mp, int flags)
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{
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struct ptyfs_hashhead *ppp;
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struct ptyfsnode *pp;
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struct vnode *vp;
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loop:
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mutex_enter(&ptyfs_used_slock);
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ppp = &ptyfs_used_tbl[PTYHASH(type, pty, ptyfs_used_mask)];
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LIST_FOREACH(pp, ppp, ptyfs_hash) {
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vp = PTYFSTOV(pp);
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if (pty == pp->ptyfs_pty && pp->ptyfs_type == type &&
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vp->v_mount == mp) {
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if (flags == 0) {
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mutex_exit(&ptyfs_used_slock);
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} else {
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mutex_enter(&vp->v_interlock);
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mutex_exit(&ptyfs_used_slock);
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if (vget(vp, flags))
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goto loop;
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}
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return vp;
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}
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}
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mutex_exit(&ptyfs_used_slock);
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return NULL;
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}
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/*
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* Insert the ptyfsnode into the used table and lock it.
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*/
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static void
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ptyfs_hashins(struct ptyfsnode *pp)
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{
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struct ptyfs_hashhead *ppp;
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/* lock the ptyfsnode, then put it on the appropriate hash list */
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VOP_LOCK(PTYFSTOV(pp), LK_EXCLUSIVE);
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mutex_enter(&ptyfs_used_slock);
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ppp = &ptyfs_used_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
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ptyfs_used_mask)];
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LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
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mutex_exit(&ptyfs_used_slock);
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}
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/*
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* Remove the ptyfsnode from the used table, and add it to the free table
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*/
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static void
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ptyfs_hashrem(struct ptyfsnode *pp)
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{
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struct ptyfs_hashhead *ppp;
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mutex_enter(&ptyfs_used_slock);
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LIST_REMOVE(pp, ptyfs_hash);
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mutex_exit(&ptyfs_used_slock);
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mutex_enter(&ptyfs_free_slock);
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ppp = &ptyfs_free_tbl[PTYHASH(pp->ptyfs_type, pp->ptyfs_pty,
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ptyfs_free_mask)];
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LIST_INSERT_HEAD(ppp, pp, ptyfs_hash);
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mutex_exit(&ptyfs_free_slock);
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}
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