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Add rudimentary support for symbolic links on UDF. Links are stored as a

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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
This commit is contained in:
John Baldwin 2009-02-06 22:24:03 +00:00
parent 643f85c491
commit e3024df2e0
2 changed files with 124 additions and 3 deletions
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12
sys/fs/udf/ecma167-udf.h
View File

@ -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;

115
sys/fs/udf/udf_vnops.c
View File

@ -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