Author: jh
Date: Thu Aug 12 15:29:07 2010
New Revision: 211226
URL: http://svn.freebsd.org/changeset/base/211226
Log:
Allow user created symbolic links to cover device files and directories
if the device file appears during or after the link creation.
User created symbolic links are now inserted at the head of the
directory entry list after the "." and ".." entries. A new directory
entry flag DE_COVERED indicates that an entry is covered by a symbolic
link.
PR: kern/114057
Reviewed by: kib
Idea from: kib
Discussed on: freebsd-current (mostly silence)
Modified:
head/sys/fs/devfs/devfs.h
head/sys/fs/devfs/devfs_devs.c
head/sys/fs/devfs/devfs_vnops.c
Modified: head/sys/fs/devfs/devfs.h
==============================================================================
--- head/sys/fs/devfs/devfs.h Thu Aug 12 15:15:30 2010 (r211225)
+++ head/sys/fs/devfs/devfs.h Thu Aug 12 15:29:07 2010 (r211226)
@@ -126,10 +126,11 @@ struct devfs_dirent {
struct cdev_priv *de_cdp;
int de_inode;
int de_flags;
-#define DE_WHITEOUT 0x1
-#define DE_DOT 0x2
-#define DE_DOTDOT 0x4
-#define DE_DOOMED 0x8
+#define DE_WHITEOUT 0x01
+#define DE_DOT 0x02
+#define DE_DOTDOT 0x04
+#define DE_DOOMED 0x08
+#define DE_COVERED 0x10
int de_holdcnt;
struct dirent *de_dirent;
TAILQ_ENTRY(devfs_dirent) de_list;
@@ -182,7 +183,7 @@ void devfs_unmount_final(struct devfs_mo
struct devfs_dirent *devfs_newdirent (char *name, int namelen);
struct devfs_dirent *devfs_parent_dirent(struct devfs_dirent *de);
struct devfs_dirent *devfs_vmkdir (struct devfs_mount *, char *name, int
namelen, struct devfs_dirent *dotdot, u_int inode);
-struct devfs_dirent *devfs_find (struct devfs_dirent *dd, const char *name,
int namelen);
+struct devfs_dirent *devfs_find(struct devfs_dirent *dd, const char *name, int
namelen, int type);
#endif /* _KERNEL */
Modified: head/sys/fs/devfs/devfs_devs.c
==============================================================================
--- head/sys/fs/devfs/devfs_devs.c Thu Aug 12 15:15:30 2010
(r211225)
+++ head/sys/fs/devfs/devfs_devs.c Thu Aug 12 15:29:07 2010
(r211226)
@@ -158,13 +158,15 @@ devfs_free(struct cdev *cdev)
}
struct devfs_dirent *
-devfs_find(struct devfs_dirent *dd, const char *name, int namelen)
+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;
@@ -235,14 +237,19 @@ devfs_vmkdir(struct devfs_mount *dmp, ch
else
dd->de_inode = alloc_unr(devfs_inos);
- /* Create the "." entry in the new directory */
+ /*
+ * "." 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 */
+ /* Create the ".." entry in the new directory. */
de = devfs_newdirent("..", 2);
de->de_dirent->d_type = DT_DIR;
de->de_flags |= DE_DOTDOT;
@@ -382,7 +389,7 @@ devfs_populate_loop(struct devfs_mount *
struct devfs_dirent *de;
struct devfs_dirent *dd;
struct cdev *pdev;
- int j;
+ int de_flags, j;
char *q, *s;
sx_assert(&dm->dm_lock, SX_XLOCKED);
@@ -454,12 +461,27 @@ devfs_populate_loop(struct devfs_mount *
continue;
if (*q != '/')
break;
- de = devfs_find(dd, s, q - s);
+ 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) {
@@ -477,6 +499,7 @@ devfs_populate_loop(struct devfs_mount *
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
Modified: head/sys/fs/devfs/devfs_vnops.c
==============================================================================
--- head/sys/fs/devfs/devfs_vnops.c Thu Aug 12 15:15:30 2010
(r211225)
+++ head/sys/fs/devfs/devfs_vnops.c Thu Aug 12 15:29:07 2010
(r211226)
@@ -822,7 +822,7 @@ devfs_lookupx(struct vop_lookup_args *ap
return (ENOENT);
}
dd = dvp->v_data;
- de = devfs_find(dd, cnp->cn_nameptr, cnp->cn_namelen);
+ de = devfs_find(dd, cnp->cn_nameptr, cnp->cn_namelen, 0);
while (de == NULL) { /* While(...) so we can use break */
if (nameiop == DELETE)
@@ -1151,7 +1151,7 @@ devfs_readdir(struct vop_readdir_args *a
off = 0;
TAILQ_FOREACH(dd, &de->de_dlist, de_list) {
KASSERT(dd->de_cdp != (void *)0xdeadc0de, ("%s %d\n", __func__,
__LINE__));
- if (dd->de_flags & DE_WHITEOUT)
+ if (dd->de_flags & (DE_COVERED | DE_WHITEOUT))
continue;
if (devfs_prison_check(dd, uio->uio_td))
continue;
@@ -1232,7 +1232,7 @@ devfs_remove(struct vop_remove_args *ap)
{
struct vnode *vp = ap->a_vp;
struct devfs_dirent *dd;
- struct devfs_dirent *de;
+ struct devfs_dirent *de, *de_covered;
struct devfs_mount *dmp = VFSTODEVFS(vp->v_mount);
sx_xlock(&dmp->dm_lock);
@@ -1240,6 +1240,12 @@ devfs_remove(struct vop_remove_args *ap)
de = vp->v_data;
if (de->de_cdp == NULL) {
TAILQ_REMOVE(&dd->de_dlist, de, de_list);
+ if (de->de_dirent->d_type == DT_LNK) {
+ de_covered = devfs_find(dd, de->de_dirent->d_name,
+ de->de_dirent->d_namlen, 0);
+ if (de_covered != NULL)
+ de_covered->de_flags &= ~DE_COVERED;
+ }
devfs_delete(dmp, de, 1);
} else {
de->de_flags |= DE_WHITEOUT;
@@ -1479,7 +1485,7 @@ devfs_symlink(struct vop_symlink_args *a
{
int i, error;
struct devfs_dirent *dd;
- struct devfs_dirent *de;
+ struct devfs_dirent *de, *de_covered, *de_dotdot;
struct devfs_mount *dmp;
error = priv_check(curthread, PRIV_DEVFS_SYMLINK);
@@ -1500,7 +1506,18 @@ devfs_symlink(struct vop_symlink_args *a
#ifdef MAC
mac_devfs_create_symlink(ap->a_cnp->cn_cred, dmp->dm_mount, dd, de);
#endif
- TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
+ de_covered = devfs_find(dd, de->de_dirent->d_name,
+ de->de_dirent->d_namlen, 0);
+ if (de_covered != NULL) {
+ KASSERT((de_covered->de_flags & DE_COVERED) == 0,
+ ("devfs_symlink: entry %p already covered", de_covered));
+ de_covered->de_flags |= DE_COVERED;
+ }
+
+ de_dotdot = TAILQ_FIRST(&dd->de_dlist); /* "." */
+ de_dotdot = TAILQ_NEXT(de_dotdot, de_list); /* ".." */
+ TAILQ_INSERT_AFTER(&dd->de_dlist, de_dotdot, de, de_list);
+
return (devfs_allocv(de, ap->a_dvp->v_mount, LK_EXCLUSIVE, ap->a_vpp));
}
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