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freebsd-dev/sys/fs/devfs/devfs_devs.c
Ed Schouten 8fac9b7b7d Merge si_name and __si_namebuf. 
The si_name pointer always points to the __si_namebuf member inside the
same object. Remove it and rename __si_namebuf to si_name.
2012-02-10 12:40:50 +00:00

709 lines
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/*-
* 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 <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <sys/kdb.h>
#include <fs/devfs/devfs.h>
#include <fs/devfs/devfs_int.h>
#include <security/mac/mac_framework.h>
/*
* The one true (but secret) list of active devices in the system.
* Locked by dev_lock()/devmtx
*/
struct cdev_priv_list cdevp_list = TAILQ_HEAD_INITIALIZER(cdevp_list);
struct unrhdr *devfs_inos;
static MALLOC_DEFINE(M_DEVFS2, "DEVFS2", "DEVFS data 2");
static MALLOC_DEFINE(M_DEVFS3, "DEVFS3", "DEVFS data 3");
static MALLOC_DEFINE(M_CDEVP, "DEVFS1", "DEVFS cdev_priv storage");
static SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW, 0, "DEVFS filesystem");
static unsigned devfs_generation;
SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD,
&devfs_generation, 0, "DEVFS generation number");
unsigned devfs_rule_depth = 1;
SYSCTL_UINT(_vfs_devfs, OID_AUTO, rule_depth, CTLFLAG_RW,
&devfs_rule_depth, 0, "Max depth of ruleset include");
/*
* Helper sysctl for devname(3). We're given a dev_t and return the
* name, if any, registered by the device driver.
*/
static int
sysctl_devname(SYSCTL_HANDLER_ARGS)
{
int error;
dev_t ud;
struct cdev_priv *cdp;
struct cdev *dev;
error = SYSCTL_IN(req, &ud, sizeof (ud));
if (error)
return (error);
if (ud == NODEV)
return (EINVAL);
dev = NULL;
dev_lock();
TAILQ_FOREACH(cdp, &cdevp_list, cdp_list)
if (cdp->cdp_inode == ud) {
dev = &cdp->cdp_c;
dev_refl(dev);
break;
}
dev_unlock();
if (dev == NULL)
return (ENOENT);
error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
dev_rel(dev);
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, devname,
CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_MPSAFE,
NULL, 0, sysctl_devname, "", "devname(3) handler");
SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev, CTLFLAG_RD,
0, sizeof(struct cdev), "sizeof(struct cdev)");
SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLAG_RD,
0, sizeof(struct cdev_priv), "sizeof(struct cdev_priv)");
struct cdev *
devfs_alloc(int flags)
{
struct cdev_priv *cdp;
struct cdev *cdev;
struct timespec ts;
cdp = malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO |
((flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK));
if (cdp == NULL)
return (NULL);
cdp->cdp_dirents = &cdp->cdp_dirent0;
cdp->cdp_dirent0 = NULL;
cdp->cdp_maxdirent = 0;
cdp->cdp_inode = 0;
cdev = &cdp->cdp_c;
LIST_INIT(&cdev->si_children);
vfs_timestamp(&ts);
cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;
cdev->si_cred = NULL;
return (cdev);
}
int
devfs_dev_exists(const char *name)
{
struct cdev_priv *cdp;
mtx_assert(&devmtx, MA_OWNED);
TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
continue;
if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
return (1);
if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
return (1);
}
if (devfs_dir_find(name) != 0)
return (1);
return (0);
}
void
devfs_free(struct cdev *cdev)
{
struct cdev_priv *cdp;
cdp = cdev2priv(cdev);
if (cdev->si_cred != NULL)
crfree(cdev->si_cred);
devfs_free_cdp_inode(cdp->cdp_inode);
if (cdp->cdp_maxdirent > 0)
free(cdp->cdp_dirents, M_DEVFS2);
free(cdp, M_CDEVP);
}
struct devfs_dirent *
devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
{
struct devfs_dirent *de;
TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
if (namelen != de->de_dirent->d_namlen)
continue;
if (type != 0 && type != de->de_dirent->d_type)
continue;
if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
continue;
break;
}
KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
("devfs_find: returning a doomed entry"));
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);
de = malloc(i, M_DEVFS3, 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;
de->de_holdcnt = 1;
#ifdef MAC
mac_devfs_init(de);
#endif
return (de);
}
struct devfs_dirent *
devfs_parent_dirent(struct devfs_dirent *de)
{
if (de->de_dirent->d_type != DT_DIR)
return (de->de_dir);
if (de->de_flags & (DE_DOT | DE_DOTDOT))
return (NULL);
de = TAILQ_FIRST(&de->de_dlist); /* "." */
if (de == NULL)
return (NULL);
de = TAILQ_NEXT(de, de_list); /* ".." */
if (de == NULL)
return (NULL);
return (de->de_dir);
}
struct devfs_dirent *
devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen, struct devfs_dirent *dotdot, u_int inode)
{
struct devfs_dirent *dd;
struct devfs_dirent *de;
/* Create the new directory */
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;
if (inode != 0)
dd->de_inode = inode;
else
dd->de_inode = alloc_unr(devfs_inos);
/*
* "." and ".." are always the two first entries in the
* de_dlist list.
*
* Create the "." entry in the new directory.
*/
de = devfs_newdirent(".", 1);
de->de_dirent->d_type = DT_DIR;
de->de_flags |= DE_DOT;
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
de->de_dir = dd;
/* Create the ".." entry in the new directory. */
de = devfs_newdirent("..", 2);
de->de_dirent->d_type = DT_DIR;
de->de_flags |= DE_DOTDOT;
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
if (dotdot == NULL) {
de->de_dir = dd;
} else {
de->de_dir = dotdot;
sx_assert(&dmp->dm_lock, SX_XLOCKED);
TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
dotdot->de_links++;
devfs_rules_apply(dmp, dd);
}
#ifdef MAC
mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
#endif
return (dd);
}
void
devfs_dirent_free(struct devfs_dirent *de)
{
free(de, M_DEVFS3);
}
/*
* Removes a directory if it is empty. Also empty parent directories are
* removed recursively.
*/
static void
devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
{
struct devfs_dirent *dd, *de_dot, *de_dotdot;
sx_assert(&dm->dm_lock, SX_XLOCKED);
for (;;) {
KASSERT(de->de_dirent->d_type == DT_DIR,
("devfs_rmdir_empty: de is not a directory"));
if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
return;
de_dot = TAILQ_FIRST(&de->de_dlist);
KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
de_dotdot = TAILQ_NEXT(de_dot, de_list);
KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
/* Return if the directory is not empty. */
if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
return;
dd = devfs_parent_dirent(de);
KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
TAILQ_REMOVE(&dd->de_dlist, de, de_list);
DEVFS_DE_HOLD(dd);
devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
if (DEVFS_DE_DROP(dd)) {
devfs_dirent_free(dd);
return;
}
de = dd;
}
}
/*
* The caller needs to hold the dm for the duration of the call since
* dm->dm_lock may be temporary dropped.
*/
void
devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
{
struct devfs_dirent *dd;
struct vnode *vp;
KASSERT((de->de_flags & DE_DOOMED) == 0,
("devfs_delete doomed dirent"));
de->de_flags |= DE_DOOMED;
if ((flags & DEVFS_DEL_NORECURSE) == 0) {
dd = devfs_parent_dirent(de);
if (dd != NULL)
DEVFS_DE_HOLD(dd);
if (de->de_flags & DE_USER) {
KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
devfs_dir_unref_de(dm, dd);
}
} else
dd = NULL;
mtx_lock(&devfs_de_interlock);
vp = de->de_vnode;
if (vp != NULL) {
VI_LOCK(vp);
mtx_unlock(&devfs_de_interlock);
vholdl(vp);
sx_unlock(&dm->dm_lock);
if ((flags & DEVFS_DEL_VNLOCKED) == 0)
vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
else
VI_UNLOCK(vp);
vgone(vp);
if ((flags & DEVFS_DEL_VNLOCKED) == 0)
VOP_UNLOCK(vp, 0);
vdrop(vp);
sx_xlock(&dm->dm_lock);
} else
mtx_unlock(&devfs_de_interlock);
if (de->de_symlink) {
free(de->de_symlink, M_DEVFS);
de->de_symlink = NULL;
}
#ifdef MAC
mac_devfs_destroy(de);
#endif
if (de->de_inode > DEVFS_ROOTINO) {
devfs_free_cdp_inode(de->de_inode);
de->de_inode = 0;
}
if (DEVFS_DE_DROP(de))
devfs_dirent_free(de);
if (dd != NULL) {
if (DEVFS_DE_DROP(dd))
devfs_dirent_free(dd);
else
devfs_rmdir_empty(dm, dd);
}
}
/*
* Called on unmount.
* Recursively removes the entire tree.
* The caller needs to hold the dm for the duration of the call.
*/
static void
devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
{
struct devfs_dirent *de;
sx_assert(&dm->dm_lock, SX_XLOCKED);
DEVFS_DE_HOLD(dd);
for (;;) {
/*
* Use TAILQ_LAST() to remove "." and ".." last.
* We might need ".." to resolve a path in
* devfs_dir_unref_de().
*/
de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
if (de == NULL)
break;
TAILQ_REMOVE(&dd->de_dlist, de, de_list);
if (de->de_flags & DE_USER)
devfs_dir_unref_de(dm, dd);
if (de->de_flags & (DE_DOT | DE_DOTDOT))
devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
else if (de->de_dirent->d_type == DT_DIR)
devfs_purge(dm, de);
else
devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
}
if (DEVFS_DE_DROP(dd))
devfs_dirent_free(dd);
else if ((dd->de_flags & DE_DOOMED) == 0)
devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
}
/*
* Each cdev_priv has an array of pointers to devfs_dirent which is indexed
* by the mount points dm_idx.
* This function extends the array when necessary, taking into account that
* the default array is 1 element and not malloc'ed.
*/
static void
devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
{
struct devfs_dirent **dep;
int siz;
siz = (dm->dm_idx + 1) * sizeof *dep;
dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
dev_lock();
if (dm->dm_idx <= cdp->cdp_maxdirent) {
/* We got raced */
dev_unlock();
free(dep, M_DEVFS2);
return;
}
memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
if (cdp->cdp_maxdirent > 0)
free(cdp->cdp_dirents, M_DEVFS2);
cdp->cdp_dirents = dep;
/*
* XXX: if malloc told us how much we actually got this could
* XXX: be optimized.
*/
cdp->cdp_maxdirent = dm->dm_idx;
dev_unlock();
}
/*
* The caller needs to hold the dm for the duration of the call.
*/
static int
devfs_populate_loop(struct devfs_mount *dm, int cleanup)
{
struct cdev_priv *cdp;
struct devfs_dirent *de;
struct devfs_dirent *dd;
struct cdev *pdev;
int de_flags, j;
char *q, *s;
sx_assert(&dm->dm_lock, SX_XLOCKED);
dev_lock();
TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
/*
* If we are unmounting, or the device has been destroyed,
* clean up our dirent.
*/
if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
dm->dm_idx <= cdp->cdp_maxdirent &&
cdp->cdp_dirents[dm->dm_idx] != NULL) {
de = cdp->cdp_dirents[dm->dm_idx];
cdp->cdp_dirents[dm->dm_idx] = NULL;
KASSERT(cdp == de->de_cdp,
("%s %d %s %p %p", __func__, __LINE__,
cdp->cdp_c.si_name, cdp, de->de_cdp));
KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
dev_unlock();
TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
de->de_cdp = NULL;
de->de_inode = 0;
devfs_delete(dm, de, 0);
dev_lock();
cdp->cdp_inuse--;
dev_unlock();
return (1);
}
/*
* GC any lingering devices
*/
if (!(cdp->cdp_flags & CDP_ACTIVE)) {
if (cdp->cdp_inuse > 0)
continue;
TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
dev_unlock();
dev_rel(&cdp->cdp_c);
return (1);
}
/*
* Don't create any new dirents if we are unmounting
*/
if (cleanup)
continue;
KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));
if (dm->dm_idx <= cdp->cdp_maxdirent &&
cdp->cdp_dirents[dm->dm_idx] != NULL) {
de = cdp->cdp_dirents[dm->dm_idx];
KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
continue;
}
cdp->cdp_inuse++;
dev_unlock();
if (dm->dm_idx > cdp->cdp_maxdirent)
devfs_metoo(cdp, dm);
dd = dm->dm_rootdir;
s = cdp->cdp_c.si_name;
for (;;) {
for (q = s; *q != '/' && *q != '\0'; q++)
continue;
if (*q != '/')
break;
de = devfs_find(dd, s, q - s, 0);
if (de == NULL)
de = devfs_vmkdir(dm, s, q - s, dd, 0);
else if (de->de_dirent->d_type == DT_LNK) {
de = devfs_find(dd, s, q - s, DT_DIR);
if (de == NULL)
de = devfs_vmkdir(dm, s, q - s, dd, 0);
de->de_flags |= DE_COVERED;
}
s = q + 1;
dd = de;
KASSERT(dd->de_dirent->d_type == DT_DIR &&
(dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
("%s: invalid directory (si_name=%s)",
__func__, cdp->cdp_c.si_name));
}
de_flags = 0;
de = devfs_find(dd, s, q - s, DT_LNK);
if (de != NULL)
de_flags |= DE_COVERED;
de = devfs_newdirent(s, q - s);
if (cdp->cdp_c.si_flags & SI_ALIAS) {
de->de_uid = 0;
de->de_gid = 0;
de->de_mode = 0755;
de->de_dirent->d_type = DT_LNK;
pdev = cdp->cdp_c.si_parent;
j = strlen(pdev->si_name) + 1;
de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
bcopy(pdev->si_name, de->de_symlink, j);
} else {
de->de_uid = cdp->cdp_c.si_uid;
de->de_gid = cdp->cdp_c.si_gid;
de->de_mode = cdp->cdp_c.si_mode;
de->de_dirent->d_type = DT_CHR;
}
de->de_flags |= de_flags;
de->de_inode = cdp->cdp_inode;
de->de_cdp = cdp;
#ifdef MAC
mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
&cdp->cdp_c, de);
#endif
de->de_dir = dd;
TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
devfs_rules_apply(dm, de);
dev_lock();
/* XXX: could check that cdp is still active here */
KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
("%s %d\n", __func__, __LINE__));
cdp->cdp_dirents[dm->dm_idx] = de;
KASSERT(de->de_cdp != (void *)0xdeadc0de,
("%s %d\n", __func__, __LINE__));
dev_unlock();
return (1);
}
dev_unlock();
return (0);
}
/*
* The caller needs to hold the dm for the duration of the call.
*/
void
devfs_populate(struct devfs_mount *dm)
{
unsigned gen;
sx_assert(&dm->dm_lock, SX_XLOCKED);
gen = devfs_generation;
if (dm->dm_generation == gen)
return;
while (devfs_populate_loop(dm, 0))
continue;
dm->dm_generation = gen;
}
/*
* The caller needs to hold the dm for the duration of the call.
*/
void
devfs_cleanup(struct devfs_mount *dm)
{
sx_assert(&dm->dm_lock, SX_XLOCKED);
while (devfs_populate_loop(dm, 1))
continue;
devfs_purge(dm, dm->dm_rootdir);
}
/*
* 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)
{
struct cdev_priv *cdp;
mtx_assert(&devmtx, MA_OWNED);
cdp = cdev2priv(dev);
cdp->cdp_flags |= CDP_ACTIVE;
cdp->cdp_inode = alloc_unrl(devfs_inos);
dev_refl(dev);
TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
devfs_generation++;
}
void
devfs_destroy(struct cdev *dev)
{
struct cdev_priv *cdp;
mtx_assert(&devmtx, MA_OWNED);
cdp = cdev2priv(dev);
cdp->cdp_flags &= ~CDP_ACTIVE;
devfs_generation++;
}
ino_t
devfs_alloc_cdp_inode(void)
{
return (alloc_unr(devfs_inos));
}
void
devfs_free_cdp_inode(ino_t ino)
{
if (ino > 0)
free_unr(devfs_inos, ino);
}
static void
devfs_devs_init(void *junk __unused)
{
devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
}
SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);
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