freebsd-skq/sys/fs/devfs/devfs_devs.c
Alexander Motin ca187878c0 Fix long known bug with handling device aliases residing not in devfs root.
Historically creation of device aliases created symbolic links using only
name of target device as a link target, not considering current directory.
Fix that by adding number of "../" chunks to the terget device name,
required to get out of the current directory to devfs root first.

MFC after:	1 month
2013-12-12 11:05:48 +00:00

717 lines
17 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 <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_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, *dt;
struct cdev *pdev;
int de_flags, depth, 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;
dt = dd;
depth = 0;
while (dt != dm->dm_rootdir &&
(dt = devfs_parent_dirent(dt)) != NULL)
depth++;
j = depth * 3 + strlen(pdev->si_name) + 1;
de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
de->de_symlink[0] = 0;
while (depth-- > 0)
strcat(de->de_symlink, "../");
strcat(de->de_symlink, pdev->si_name);
} 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 necessary 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);