[XFS] Hook up compat XFS_IOC_ATTRLIST_BY_HANDLE ioctl handler

Add a compat handler for XFS_IOC_ATTRLIST_BY_HANDLE

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

2 files changed, 147 insertions, 1 deletions

diff --git a/fs/xfs/linux-2.6/xfs_ioctl32.c b/fs/xfs/linux-2.6/xfs_ioctl32.c
index cc1fe96efab5..e7eb0d7e0d56 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl32.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl32.c
@@ -46,6 +46,7 @@
 #include "xfs_fsops.h"
 #include "xfs_alloc.h"
 #include "xfs_rtalloc.h"
+#include "xfs_attr.h"
 #include "xfs_ioctl.h"
 #include "xfs_ioctl32.h"
 
@@ -343,6 +344,138 @@ xfs_compat_handlereq_copyin(
         return 0;
 }
 
+/*
+ * Convert userspace handle data into inode.
+ *
+ * We use the fact that all the fsop_handlereq ioctl calls have a data
+ * structure argument whose first component is always a xfs_fsop_handlereq_t,
+ * so we can pass that sub structure into this handy, shared routine.
+ *
+ * If no error, caller must always iput the returned inode.
+ */
+STATIC int
+xfs_vget_fsop_handlereq_compat(
+        xfs_mount_t             *mp,
+        struct inode            *parinode,      /* parent inode pointer    */
+        compat_xfs_fsop_handlereq_t     *hreq,
+        struct inode            **inode)
+{
+        void                    __user *hanp;
+        size_t                  hlen;
+        xfs_fid_t               *xfid;
+        xfs_handle_t            *handlep;
+        xfs_handle_t            handle;
+        xfs_inode_t             *ip;
+        xfs_ino_t               ino;
+        __u32                   igen;
+        int                     error;
+
+        /*
+         * Only allow handle opens under a directory.
+         */
+        if (!S_ISDIR(parinode->i_mode))
+                return XFS_ERROR(ENOTDIR);
+
+        hanp = compat_ptr(hreq->ihandle);
+        hlen = hreq->ihandlen;
+        handlep = &handle;
+
+        if (hlen < sizeof(handlep->ha_fsid) || hlen > sizeof(*handlep))
+                return XFS_ERROR(EINVAL);
+        if (copy_from_user(handlep, hanp, hlen))
+                return XFS_ERROR(EFAULT);
+        if (hlen < sizeof(*handlep))
+                memset(((char *)handlep) + hlen, 0, sizeof(*handlep) - hlen);
+        if (hlen > sizeof(handlep->ha_fsid)) {
+                if (handlep->ha_fid.fid_len !=
+                    (hlen - sizeof(handlep->ha_fsid) -
+                            sizeof(handlep->ha_fid.fid_len)) ||
+                    handlep->ha_fid.fid_pad)
+                        return XFS_ERROR(EINVAL);
+        }
+
+        /*
+         * Crack the handle, obtain the inode # & generation #
+         */
+        xfid = (struct xfs_fid *)&handlep->ha_fid;
+        if (xfid->fid_len == sizeof(*xfid) - sizeof(xfid->fid_len)) {
+                ino  = xfid->fid_ino;
+                igen = xfid->fid_gen;
+        } else {
+                return XFS_ERROR(EINVAL);
+        }
+
+        /*
+         * Get the XFS inode, building a Linux inode to go with it.
+         */
+        error = xfs_iget(mp, NULL, ino, 0, XFS_ILOCK_SHARED, &ip, 0);
+        if (error)
+                return error;
+        if (ip == NULL)
+                return XFS_ERROR(EIO);
+        if (ip->i_d.di_gen != igen) {
+                xfs_iput_new(ip, XFS_ILOCK_SHARED);
+                return XFS_ERROR(ENOENT);
+        }
+
+        xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+        *inode = VFS_I(ip);
+        return 0;
+}
+
+STATIC int
+xfs_compat_attrlist_by_handle(
+        xfs_mount_t             *mp,
+        void                    __user *arg,
+        struct inode            *parinode)
+{
+        int                     error;
+        attrlist_cursor_kern_t  *cursor;
+        compat_xfs_fsop_attrlist_handlereq_t al_hreq;
+        struct inode            *inode;
+        char                    *kbuf;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -XFS_ERROR(EPERM);
+        if (copy_from_user(&al_hreq, arg,
+                           sizeof(compat_xfs_fsop_attrlist_handlereq_t)))
+                return -XFS_ERROR(EFAULT);
+        if (al_hreq.buflen > XATTR_LIST_MAX)
+                return -XFS_ERROR(EINVAL);
+
+        /*
+         * Reject flags, only allow namespaces.
+         */
+        if (al_hreq.flags & ~(ATTR_ROOT | ATTR_SECURE))
+                return -XFS_ERROR(EINVAL);
+
+        error = xfs_vget_fsop_handlereq_compat(mp, parinode, &al_hreq.hreq,
+                                               &inode);
+        if (error)
+                goto out;
+
+        kbuf = kmalloc(al_hreq.buflen, GFP_KERNEL);
+        if (!kbuf)
+                goto out_vn_rele;
+
+        cursor = (attrlist_cursor_kern_t *)&al_hreq.pos;
+        error = xfs_attr_list(XFS_I(inode), kbuf, al_hreq.buflen,
+                                        al_hreq.flags, cursor);
+        if (error)
+                goto out_kfree;
+
+        if (copy_to_user(compat_ptr(al_hreq.buffer), kbuf, al_hreq.buflen))
+                error = -EFAULT;
+
+ out_kfree:
+        kfree(kbuf);
+ out_vn_rele:
+        iput(inode);
+ out:
+        return -error;
+}
+
 STATIC long
 xfs_compat_ioctl(
         xfs_inode_t     *ip,
@@ -368,7 +501,6 @@ xfs_compat_ioctl(
         case XFS_IOC_GETBMAPX:
 /* not handled
         case XFS_IOC_FSSETDM_BY_HANDLE:
-        case XFS_IOC_ATTRLIST_BY_HANDLE:
         case XFS_IOC_ATTRMULTI_BY_HANDLE:
 */
         case XFS_IOC_FSCOUNTS:
@@ -476,6 +608,8 @@ xfs_compat_ioctl(
                         return -XFS_ERROR(EFAULT);
                 return xfs_readlink_by_handle(mp, &hreq, inode);
         }
+        case XFS_IOC_ATTRLIST_BY_HANDLE_32:
+                return xfs_compat_attrlist_by_handle(mp, arg, inode);
         default:
                 return -XFS_ERROR(ENOIOCTLCMD);
         }
diff --git a/fs/xfs/linux-2.6/xfs_ioctl32.h b/fs/xfs/linux-2.6/xfs_ioctl32.h
index 8b2a12a8e96f..bbf3a2cd8a7d 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl32.h
+++ b/fs/xfs/linux-2.6/xfs_ioctl32.h
@@ -123,6 +123,18 @@ typedef struct compat_xfs_swapext {
 
 #define XFS_IOC_SWAPEXT_32      _IOWR('X', 109, struct compat_xfs_swapext)
 
+typedef struct compat_xfs_fsop_attrlist_handlereq {
+        struct compat_xfs_fsop_handlereq hreq; /* handle interface structure */
+        struct xfs_attrlist_cursor      pos; /* opaque cookie, list offset */
+        __u32                           flags;  /* which namespace to use */
+        __u32                           buflen; /* length of buffer supplied */
+        compat_uptr_t                   buffer; /* returned names */
+} __compat_packed compat_xfs_fsop_attrlist_handlereq_t;
+
+/* Note: actually this is read/write */
+#define XFS_IOC_ATTRLIST_BY_HANDLE_32 \
+        _IOW('X', 122, struct compat_xfs_fsop_attrlist_handlereq)
+
 #ifdef BROKEN_X86_ALIGNMENT
 /* on ia32 l_start is on a 32-bit boundary */
 typedef struct compat_xfs_flock64 {