freebsd-skq/sys/fs/devfs/devfs_devs.c
Dima Dorfman a1dc209638 Introduce the DEVFS "rule" subsystem. DEVFS rules permit the
administrator to define certain properties of new devfs nodes before
they become visible to the userland.  Both static (e.g., /dev/speaker)
and dynamic (e.g., /dev/bpf*, some removable devices) nodes are
supported.  Each DEVFS mount may have a different ruleset assigned to
it, permitting different policies to be implemented for things like
jails.

Approved by:	phk
2002-07-17 01:46:48 +00:00

445 lines
10 KiB
C

#define DEBUG 1
/*
* Copyright (c) 2000
* Poul-Henning Kamp. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* From: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
*
* $FreeBSD$
*/
#include "opt_devfs.h"
#ifndef NODEVFS
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <machine/atomic.h>
#include <fs/devfs/devfs.h>
static dev_t devfs_inot[NDEVFSINO];
static dev_t *devfs_overflow;
static int devfs_ref[NDEVFSINO];
static int *devfs_refoverflow;
static int devfs_nextino = 3;
static int devfs_numino;
static int devfs_topino;
static int devfs_noverflowwant = NDEVFSOVERFLOW;
static int devfs_noverflow;
static unsigned devfs_generation;
static void devfs_attemptoverflow(int insist);
static struct devfs_dirent *devfs_find (struct devfs_dirent *dd, const char *name, int namelen);
SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem");
SYSCTL_UINT(_vfs_devfs, OID_AUTO, noverflow, CTLFLAG_RW,
&devfs_noverflowwant, 0, "Size of DEVFS overflow table");
SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD,
&devfs_generation, 0, "DEVFS generation number");
SYSCTL_UINT(_vfs_devfs, OID_AUTO, inodes, CTLFLAG_RD,
&devfs_numino, 0, "DEVFS inodes");
SYSCTL_UINT(_vfs_devfs, OID_AUTO, topinode, CTLFLAG_RD,
&devfs_topino, 0, "DEVFS highest inode#");
static int *
devfs_itor(int inode)
{
if (inode < NDEVFSINO)
return (&devfs_ref[inode]);
else if (inode < NDEVFSINO + devfs_noverflow)
return (&devfs_refoverflow[inode - NDEVFSINO]);
else
panic ("YRK!");
}
static void
devfs_dropref(int inode)
{
int *ip;
ip = devfs_itor(inode);
atomic_add_int(ip, -1);
}
static int
devfs_getref(int inode)
{
int *ip, i, j;
dev_t *dp;
ip = devfs_itor(inode);
dp = devfs_itod(inode);
for (;;) {
i = *ip;
j = i + 1;
if (!atomic_cmpset_int(ip, i, j))
continue;
if (*dp != NULL)
return (1);
atomic_add_int(ip, -1);
return(0);
}
}
struct devfs_dirent **
devfs_itode (struct devfs_mount *dm, int inode)
{
if (inode < NDEVFSINO)
return (&dm->dm_dirent[inode]);
if (devfs_overflow == NULL)
return (NULL);
if (inode < NDEVFSINO + devfs_noverflow)
return (&dm->dm_overflow[inode - NDEVFSINO]);
return (NULL);
}
dev_t *
devfs_itod (int inode)
{
if (inode < NDEVFSINO)
return (&devfs_inot[inode]);
if (devfs_overflow == NULL)
return (NULL);
if (inode < NDEVFSINO + devfs_noverflow)
return (&devfs_overflow[inode - NDEVFSINO]);
return (NULL);
}
static void
devfs_attemptoverflow(int insist)
{
dev_t **ot;
int *or;
int n, nb;
/* Check if somebody beat us to it */
if (devfs_overflow != NULL)
return;
ot = NULL;
or = NULL;
n = devfs_noverflowwant;
nb = sizeof (struct dev_t *) * n;
MALLOC(ot, dev_t **, nb, M_DEVFS, (insist ? M_WAITOK : M_NOWAIT) | M_ZERO);
if (ot == NULL)
goto bail;
nb = sizeof (int) * n;
MALLOC(or, int *, nb, M_DEVFS, (insist ? M_WAITOK : M_NOWAIT) | M_ZERO);
if (or == NULL)
goto bail;
if (!atomic_cmpset_ptr(&devfs_overflow, NULL, ot))
goto bail;
devfs_refoverflow = or;
devfs_noverflow = n;
printf("DEVFS Overflow table with %d entries allocated when %d in use\n", n, devfs_numino);
return;
bail:
/* Somebody beat us to it, or something went wrong. */
if (ot != NULL)
FREE(ot, M_DEVFS);
if (or != NULL)
FREE(or, M_DEVFS);
return;
}
static struct devfs_dirent *
devfs_find(struct devfs_dirent *dd, const char *name, int namelen)
{
struct devfs_dirent *de;
TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
if (namelen != de->de_dirent->d_namlen)
continue;
if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
continue;
break;
}
return (de);
}
struct devfs_dirent *
devfs_newdirent(char *name, int namelen)
{
int i;
struct devfs_dirent *de;
struct dirent d;
d.d_namlen = namelen;
i = sizeof (*de) + GENERIC_DIRSIZ(&d);
MALLOC(de, struct devfs_dirent *, i, M_DEVFS, M_WAITOK | M_ZERO);
de->de_dirent = (struct dirent *)(de + 1);
de->de_dirent->d_namlen = namelen;
de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
bcopy(name, de->de_dirent->d_name, namelen);
de->de_dirent->d_name[namelen] = '\0';
vfs_timestamp(&de->de_ctime);
de->de_mtime = de->de_atime = de->de_ctime;
de->de_links = 1;
return (de);
}
struct devfs_dirent *
devfs_vmkdir(char *name, int namelen, struct devfs_dirent *dotdot)
{
struct devfs_dirent *dd;
struct devfs_dirent *de;
dd = devfs_newdirent(name, namelen);
TAILQ_INIT(&dd->de_dlist);
dd->de_dirent->d_type = DT_DIR;
dd->de_mode = 0555;
dd->de_links = 2;
dd->de_dir = dd;
de = devfs_newdirent(".", 1);
de->de_dirent->d_type = DT_DIR;
de->de_dir = dd;
de->de_flags |= DE_DOT;
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
de = devfs_newdirent("..", 2);
de->de_dirent->d_type = DT_DIR;
if (dotdot == NULL)
de->de_dir = dd;
else
de->de_dir = dotdot;
de->de_flags |= DE_DOTDOT;
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
return (dd);
}
static void
devfs_delete(struct devfs_dirent *dd, struct devfs_dirent *de)
{
if (de->de_symlink) {
FREE(de->de_symlink, M_DEVFS);
de->de_symlink = NULL;
}
if (de->de_vnode)
de->de_vnode->v_data = NULL;
TAILQ_REMOVE(&dd->de_dlist, de, de_list);
FREE(de, M_DEVFS);
}
void
devfs_purge(struct devfs_dirent *dd)
{
struct devfs_dirent *de;
for (;;) {
de = TAILQ_FIRST(&dd->de_dlist);
if (de == NULL)
break;
devfs_delete(dd, de);
}
FREE(dd, M_DEVFS);
}
int
devfs_populate(struct devfs_mount *dm)
{
int i, j;
dev_t dev, pdev;
struct devfs_dirent *dd;
struct devfs_dirent *de, **dep;
char *q, *s;
if (dm->dm_generation == devfs_generation)
return (0);
lockmgr(&dm->dm_lock, LK_UPGRADE, 0, curthread);
if (devfs_noverflow && dm->dm_overflow == NULL) {
i = devfs_noverflow * sizeof (struct devfs_dirent *);
MALLOC(dm->dm_overflow, struct devfs_dirent **, i,
M_DEVFS, M_WAITOK | M_ZERO);
}
while (dm->dm_generation != devfs_generation) {
dm->dm_generation = devfs_generation;
for (i = 0; i <= devfs_topino; i++) {
dev = *devfs_itod(i);
dep = devfs_itode(dm, i);
de = *dep;
if (dev == NULL && de == DE_DELETED) {
*dep = NULL;
continue;
}
if (dev == NULL && de != NULL) {
dd = de->de_dir;
*dep = NULL;
TAILQ_REMOVE(&dd->de_dlist, de, de_list);
if (de->de_vnode)
de->de_vnode->v_data = NULL;
FREE(de, M_DEVFS);
devfs_dropref(i);
continue;
}
if (dev == NULL)
continue;
if (de != NULL)
continue;
if (!devfs_getref(i))
continue;
dd = dm->dm_basedir;
s = dev->si_name;
for (;;) {
for (q = s; *q != '/' && *q != '\0'; q++)
continue;
if (*q != '/')
break;
de = devfs_find(dd, s, q - s);
if (de == NULL) {
de = devfs_vmkdir(s, q - s, dd);
de->de_inode = dm->dm_inode++;
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
dd->de_links++;
}
s = q + 1;
dd = de;
}
de = devfs_newdirent(s, q - s);
if (dev->si_flags & SI_ALIAS) {
de->de_inode = dm->dm_inode++;
de->de_uid = 0;
de->de_gid = 0;
de->de_mode = 0755;
de->de_dirent->d_type = DT_LNK;
pdev = dev->si_parent;
j = strlen(pdev->si_name) + 1;
MALLOC(de->de_symlink, char *, j, M_DEVFS, M_WAITOK);
bcopy(pdev->si_name, de->de_symlink, j);
} else {
de->de_inode = i;
de->de_uid = dev->si_uid;
de->de_gid = dev->si_gid;
de->de_mode = dev->si_mode;
de->de_dirent->d_type = DT_CHR;
}
*dep = de;
de->de_dir = dd;
devfs_rules_apply(dm, de);
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
#if 0
printf("Add ino%d %s\n", i, dev->si_name);
#endif
}
}
lockmgr(&dm->dm_lock, LK_DOWNGRADE, 0, curthread);
return (0);
}
static void
devfs_create(dev_t dev)
{
int ino, i, *ip;
dev_t *dp;
for (;;) {
/* Grab the next inode number */
ino = devfs_nextino;
i = ino + 1;
/* wrap around when we reach the end */
if (i >= NDEVFSINO + devfs_noverflow)
i = 3;
if (!atomic_cmpset_int(&devfs_nextino, ino, i))
continue;
/* see if it was occupied */
dp = devfs_itod(ino);
if (dp == NULL)
Debugger("dp == NULL\n");
if (*dp != NULL)
continue;
ip = devfs_itor(ino);
if (ip == NULL)
Debugger("ip == NULL\n");
if (*ip != 0)
continue;
if (!atomic_cmpset_ptr(dp, NULL, dev))
continue;
dev->si_inode = ino;
for (;;) {
i = devfs_topino;
if (i >= ino)
break;
if (atomic_cmpset_int(&devfs_topino, i, ino))
break;
printf("failed topino %d %d\n", i, ino);
}
break;
}
atomic_add_int(&devfs_numino, 1);
atomic_add_int(&devfs_generation, 1);
if (devfs_overflow == NULL && devfs_numino + 100 > NDEVFSINO)
devfs_attemptoverflow(0);
}
static void
devfs_destroy(dev_t dev)
{
int ino, i;
ino = dev->si_inode;
dev->si_inode = 0;
if (ino == 0)
return;
if (atomic_cmpset_ptr(devfs_itod(ino), dev, NULL)) {
atomic_add_int(&devfs_generation, 1);
atomic_add_int(&devfs_numino, -1);
i = devfs_nextino;
if (ino < i)
atomic_cmpset_int(&devfs_nextino, i, ino);
}
}
static void
devfs_init(void *junk)
{
devfs_create_hook = devfs_create;
devfs_destroy_hook = devfs_destroy;
devfs_present = 1;
devfs_rules_init();
}
SYSINIT(devfs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_init, NULL);
#endif