Author: jhb
Date: Fri Feb 6 22:24:03 2009
New Revision: 188251
URL: http://svn.freebsd.org/changeset/base/188251
Log:
Add rudimentary support for symbolic links on UDF. Links are stored as a
sequence of pathname components. We walk the list building a string in
the caller's passed in buffer. Currently this only handles path names
in CS8 (character set 8) as that is what mkisofs generates for UDF images.
MFC after: 1 month
Modified:
head/sys/fs/udf/ecma167-udf.h
head/sys/fs/udf/udf_vnops.c
Modified: head/sys/fs/udf/ecma167-udf.h
==============================================================================
--- head/sys/fs/udf/ecma167-udf.h Fri Feb 6 22:22:08 2009
(r188250)
+++ head/sys/fs/udf/ecma167-udf.h Fri Feb 6 22:24:03 2009
(r188251)
@@ -354,6 +354,18 @@ struct file_entry {
#define UDF_FENTRY_PERM_GRP_MASK 0xE0
#define UDF_FENTRY_PERM_OWNER_MASK 0x1C00
+/* Path Component [4/14.16.1] */
+struct path_component {
+ uint8_t type;
+ uint8_t length;
+ uint16_t version;
+ uint8_t identifier[0];
+} __packed;
+#define UDF_PATH_ROOT 2
+#define UDF_PATH_DOTDOT 3
+#define UDF_PATH_DOT 4
+#define UDF_PATH_PATH 5
+
union dscrptr {
struct desc_tag tag;
struct anchor_vdp avdp;
Modified: head/sys/fs/udf/udf_vnops.c
==============================================================================
--- head/sys/fs/udf/udf_vnops.c Fri Feb 6 22:22:08 2009 (r188250)
+++ head/sys/fs/udf/udf_vnops.c Fri Feb 6 22:24:03 2009 (r188251)
@@ -859,12 +859,121 @@ udf_readdir(struct vop_readdir_args *a)
return (error);
}
-/* Are there any implementations out there that do soft-links? */
static int
udf_readlink(struct vop_readlink_args *ap)
{
- printf("%s called\n", __func__);
- return (EOPNOTSUPP);
+ struct path_component *pc, *end;
+ struct vnode *vp;
+ struct uio uio;
+ struct iovec iov[1];
+ struct udf_node *node;
+ void *buf;
+ char *cp;
+ int error, len, root;
+
+ /*
+ * A symbolic link in UDF is a list of variable-length path
+ * component structures. We build a pathname in the caller's
+ * uio by traversing this list.
+ */
+ vp = ap->a_vp;
+ node = VTON(vp);
+ len = le64toh(node->fentry->inf_len);
+ buf = malloc(iov[0].iov_len, M_DEVBUF, M_WAITOK);
+ iov[0].iov_base = buf;
+ iov[0].iov_len = len;
+ uio.uio_iov = iov;
+ uio.uio_iovcnt = 1;
+ uio.uio_offset = 0;
+ uio.uio_resid = iov[0].iov_len;
+ uio.uio_segflg = UIO_SYSSPACE;
+ uio.uio_rw = UIO_READ;
+ uio.uio_td = curthread;
+ error = VOP_READ(vp, &uio, 0, ap->a_cred);
+ if (error)
+ goto error;
+
+ pc = buf;
+ end = (void *)((char *)buf + len);
+ root = 0;
+ while (pc < end) {
+ switch (pc->type) {
+ case UDF_PATH_ROOT:
+ /* Only allow this at the beginning of a path. */
+ if ((void *)pc != buf) {
+ error = EINVAL;
+ goto error;
+ }
+ cp = "/";
+ len = 1;
+ root = 1;
+ break;
+ case UDF_PATH_DOT:
+ cp = ".";
+ len = 1;
+ break;
+ case UDF_PATH_DOTDOT:
+ cp = "..";
+ len = 2;
+ break;
+ case UDF_PATH_PATH:
+ if (pc->length == 0) {
+ error = EINVAL;
+ goto error;
+ }
+ /*
+ * XXX: We only support CS8 which appears to map
+ * to ASCII directly.
+ */
+ switch (pc->identifier[0]) {
+ case 8:
+ cp = pc->identifier + 1;
+ len = pc->length - 1;
+ break;
+ default:
+ error = EOPNOTSUPP;
+ goto error;
+ }
+ break;
+ default:
+ error = EINVAL;
+ goto error;
+ }
+
+ /*
+ * If this is not the first component, insert a path
+ * separator.
+ */
+ if (pc != buf) {
+ /* If we started with root we already have a "/". */
+ if (root)
+ goto skipslash;
+ root = 0;
+ if (ap->a_uio->uio_resid < 1) {
+ error = ENAMETOOLONG;
+ goto error;
+ }
+ error = uiomove("/", 1, ap->a_uio);
+ if (error)
+ break;
+ }
+ skipslash:
+
+ /* Append string at 'cp' of length 'len' to our path. */
+ if (len > ap->a_uio->uio_resid) {
+ error = ENAMETOOLONG;
+ goto error;
+ }
+ error = uiomove(cp, len, ap->a_uio);
+ if (error)
+ break;
+
+ /* Advance to next component. */
+ pc = (void *)((char *)pc + 4 + pc->length);
+ }
+error:
+ free(buf, M_DEVBUF);
+ return (error);
}
static int
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