freebsd-dev/sys/fs/devfs/devfs_devs.c
Poul-Henning Kamp 9d96090725 Reduce a fair bit of the atomics because we are now called with a
lock from kern_conf.c and cdev's act a lot more like real objects
these days.
2004-06-18 08:08:47 +00:00

427 lines
10 KiB
C

/*
* Copyright (c) 2000,2004
* 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"
#include "opt_mac.h"
#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/mac.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 struct cdev *devfs_inot[NDEVFSINO];
static struct cdev **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 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;
struct cdev **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);
}
struct cdev **
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 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;
#ifdef MAC
mac_init_devfsdirent(de);
#endif
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);
#ifdef MAC
mac_destroy_devfsdirent(de);
#endif
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;
struct cdev *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);
#ifdef MAC
mac_create_devfs_directory(
dm->dm_mount, s, q - s, de);
#endif
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;
}
#ifdef MAC
mac_create_devfs_device(dm->dm_mount, dev, de);
#endif
*dep = de;
de->de_dir = dd;
devfs_rules_apply(dm, de);
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
}
}
lockmgr(&dm->dm_lock, LK_DOWNGRADE, 0, curthread);
return (0);
}
/*
* devfs_create() and devfs_destroy() are called from kern_conf.c and
* in both cases the devlock() mutex is held, so no further locking
* is necesary and no sleeping allowed.
*/
void
devfs_create(struct cdev *dev)
{
int ino, i, *ip;
struct cdev **dp;
struct cdev **ot;
int *or;
int n;
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;
devfs_nextino = i;
/* see if it was occupied */
dp = devfs_itod(ino);
KASSERT(dp != NULL, ("DEVFS: No devptr inode %d", ino));
if (*dp != NULL)
continue;
ip = devfs_itor(ino);
KASSERT(ip != NULL, ("DEVFS: No iptr inode %d", ino));
if (*ip != 0)
continue;
break;
}
*dp = dev;
dev->si_inode = ino;
if (i > devfs_topino)
devfs_topino = i;
devfs_numino++;
devfs_generation++;
if (devfs_overflow != NULL || devfs_numino + 100 < NDEVFSINO)
return;
/*
* Try to allocate overflow table
* XXX: we can probably be less panicy these days and a linked
* XXX: list of PAGESIZE/PTRSIZE entries might be a better idea.
*
* XXX: we may be into witness unlove here.
*/
n = devfs_noverflowwant;
ot = malloc(sizeof(*ot) * n, M_DEVFS, M_NOWAIT | M_ZERO);
if (ot == NULL)
return;
or = malloc(sizeof(*or) * n, M_DEVFS, M_NOWAIT | M_ZERO);
if (or == NULL) {
free(ot, M_DEVFS);
return;
}
devfs_overflow = ot;
devfs_refoverflow = or;
devfs_noverflow = n;
printf("DEVFS Overflow table with %d entries allocated\n", n);
return;
}
void
devfs_destroy(struct cdev *dev)
{
int ino;
struct cdev **dp;
ino = dev->si_inode;
dev->si_inode = 0;
if (ino == 0)
return;
dp = devfs_itod(ino);
KASSERT(*dp == dev,
("DEVFS: destroying wrong cdev ino %d", ino));
*dp = NULL;
devfs_numino--;
devfs_generation++;
if (ino < devfs_nextino)
devfs_nextino = ino;
}