[Xen-devel] [PATCH v3 4/9] xen: add basic hypervisor filesystem support

[Juergen Gross <jgross@suse.com>]

Add the infrastructure for the hypervisor filesystem.

This includes the hypercall interface and the base functions for
entry creation, deletion and modification.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V1:
- rename files from filesystem.* to hypfs.*
- add dummy write entry support
- rename hypercall filesystem_op to hypfs_op
- add support for unsigned integer entries

V2:
- test new entry name to be valid

V3:
- major rework, especially by supporting binary contents of entries
- addressed all comments
---
 xen/arch/arm/traps.c         |   1 +
 xen/arch/x86/hvm/hypercall.c |   1 +
 xen/arch/x86/hypercall.c     |   1 +
 xen/arch/x86/pv/hypercall.c  |   1 +
 xen/common/Makefile          |   1 +
 xen/common/hypfs.c           | 365 +++++++++++++++++++++++++++++++++++++++++++
 xen/include/public/hypfs.h   | 124 +++++++++++++++
 xen/include/public/xen.h     |   1 +
 xen/include/xen/hypercall.h  |   8 +
 xen/include/xen/hypfs.h      |  89 +++++++++++
 10 files changed, 592 insertions(+)
 create mode 100644 xen/common/hypfs.c
 create mode 100644 xen/include/public/hypfs.h
 create mode 100644 xen/include/xen/hypfs.h

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 6f9bec22d3..87af810667 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1382,6 +1382,7 @@ static arm_hypercall_t arm_hypercall_table[] = {
 #ifdef CONFIG_ARGO
     HYPERCALL(argo_op, 5),
 #endif
+    HYPERCALL(hypfs_op, 5),
 };
 
 #ifndef NDEBUG
diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index 33dd2d99d2..210dda4f38 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -144,6 +144,7 @@ static const hypercall_table_t hvm_hypercall_table[] = {
 #endif
     HYPERCALL(xenpmu_op),
     COMPAT_CALL(dm_op),
+    HYPERCALL(hypfs_op),
     HYPERCALL(arch_1)
 };
 
diff --git a/xen/arch/x86/hypercall.c b/xen/arch/x86/hypercall.c
index 7f299d45c6..05a3f5e25b 100644
--- a/xen/arch/x86/hypercall.c
+++ b/xen/arch/x86/hypercall.c
@@ -73,6 +73,7 @@ const hypercall_args_t hypercall_args_table[NR_hypercalls] =
     ARGS(hvm_op, 2),
     ARGS(dm_op, 3),
 #endif
+    ARGS(hypfs_op, 5),
     ARGS(mca, 1),
     ARGS(arch_1, 1),
 };
diff --git a/xen/arch/x86/pv/hypercall.c b/xen/arch/x86/pv/hypercall.c
index 17ddf9ea1f..83907d4f00 100644
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -85,6 +85,7 @@ const hypercall_table_t pv_hypercall_table[] = {
     HYPERCALL(hvm_op),
     COMPAT_CALL(dm_op),
 #endif
+    HYPERCALL(hypfs_op),
     HYPERCALL(mca),
     HYPERCALL(arch_1),
 };
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 62b34e69e9..a3f66aa0c0 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -11,6 +11,7 @@ obj-y += domain.o
 obj-y += event_2l.o
 obj-y += event_channel.o
 obj-y += event_fifo.o
+obj-y += hypfs.o
 obj-$(CONFIG_CRASH_DEBUG) += gdbstub.o
 obj-$(CONFIG_GRANT_TABLE) += grant_table.o
 obj-y += guestcopy.o
diff --git a/xen/common/hypfs.c b/xen/common/hypfs.c
new file mode 100644
index 0000000000..6762d20dfd
--- /dev/null
+++ b/xen/common/hypfs.c
@@ -0,0 +1,365 @@
+/******************************************************************************
+ *
+ * hypfs.c
+ *
+ * Simple sysfs-like file system for the hypervisor.
+ */
+
+#include <xen/lib.h>
+#include <xen/err.h>
+#include <xen/guest_access.h>
+#include <xen/hypercall.h>
+#include <xen/hypfs.h>
+#include <xen/rwlock.h>
+#include <public/hypfs.h>
+
+#define DIRENTRY_NAME_OFF offsetof(struct xen_hypfs_dirlistentry, name)
+#define DIRENTRY_SIZE(name_len) \
+    (DIRENTRY_NAME_OFF + ROUNDUP(name_len, alignof(struct xen_hypfs_direntry)))
+
+static DEFINE_RWLOCK(hypfs_lock);
+
+HYPFS_DIR_INIT(hypfs_root, "");
+
+static int add_entry(struct hypfs_entry_dir *parent, struct hypfs_entry *new)
+{
+    int ret = -ENOENT;
+    struct hypfs_entry *e;
+
+    write_lock(&hypfs_lock);
+
+    list_for_each_entry ( e, &parent->dirlist, list )
+    {
+        int cmp = strcmp(e->name, new->name);
+
+        if ( cmp > 0 )
+        {
+            ret = 0;
+            list_add_tail(&new->list, &e->list);
+            break;
+        }
+        if ( cmp == 0 )
+        {
+            ret = -EEXIST;
+            break;
+        }
+    }
+
+    if ( ret == -ENOENT )
+    {
+        ret = 0;
+        list_add_tail(&new->list, &parent->dirlist);
+    }
+
+    if ( !ret )
+    {
+        unsigned int sz = strlen(new->name) + 1;
+
+        parent->e.size += DIRENTRY_SIZE(sz);
+    }
+
+    write_unlock(&hypfs_lock);
+
+    return ret;
+}
+
+int hypfs_add_entry(struct hypfs_entry_dir *parent,
+                    struct hypfs_entry *entry, bool nofault)
+{
+    int ret;
+
+    ret = add_entry(parent, entry);
+    BUG_ON(nofault && ret);
+
+    return ret;
+}
+
+int hypfs_add_dir(struct hypfs_entry_dir *parent,
+                  struct hypfs_entry_dir *dir, bool nofault)
+{
+    int ret;
+
+    ret = add_entry(parent, &dir->e);
+    BUG_ON(nofault && ret);
+
+    return ret;
+}
+
+int hypfs_add_leaf(struct hypfs_entry_dir *parent,
+                   struct hypfs_entry_leaf *leaf, bool nofault)
+{
+    int ret;
+
+    if ( !leaf->content )
+        ret = -EINVAL;
+    else
+        ret = add_entry(parent, &leaf->e);
+    BUG_ON(nofault && ret);
+
+    return ret;
+}
+
+static int hypfs_get_path_user(char *buf, XEN_GUEST_HANDLE_PARAM(void) uaddr,
+                               unsigned long len)
+{
+    if ( len > XEN_HYPFS_MAX_PATHLEN )
+        return -EINVAL;
+
+    if ( copy_from_guest(buf, uaddr, len) )
+        return -EFAULT;
+
+    if ( buf[len - 1] )
+        return -EINVAL;
+
+    return 0;
+}
+
+static struct hypfs_entry *hypfs_get_entry_rel(struct hypfs_entry_dir *dir,
+                                               const char *path)
+{
+    const char *end;
+    struct hypfs_entry *entry;
+    unsigned int name_len;
+
+    if ( !*path )
+        return &dir->e;
+
+    if ( dir->e.type != XEN_HYPFS_TYPE_DIR )
+        return NULL;
+
+    end = strchr(path, '/');
+    if ( !end )
+        end = strchr(path, '\0');
+    name_len = end - path;
+
+    list_for_each_entry ( entry, &dir->dirlist, list )
+    {
+        int cmp = strncmp(path, entry->name, name_len);
+	struct hypfs_entry_dir *d = container_of(entry,
+                                                 struct hypfs_entry_dir, e);
+
+        if ( cmp < 0 )
+            return NULL;
+        if ( !cmp && strlen(entry->name) == name_len )
+            return *end ? hypfs_get_entry_rel(d, end + 1) : entry;
+    }
+
+    return NULL;
+}
+
+struct hypfs_entry *hypfs_get_entry(const char *path)
+{
+    if ( path[0] != '/' )
+        return NULL;
+
+    return hypfs_get_entry_rel(&hypfs_root, path + 1);
+}
+
+int hypfs_read_dir(const struct hypfs_entry *entry,
+                   XEN_GUEST_HANDLE_PARAM(void) uaddr)
+{
+    const struct hypfs_entry_dir *d;
+    struct hypfs_entry *e;
+    unsigned int size = entry->size;
+
+    d = container_of(entry, const struct hypfs_entry_dir, e);
+
+    list_for_each_entry ( e, &d->dirlist, list )
+    {
+        struct xen_hypfs_dirlistentry direntry;
+        unsigned int e_namelen = strlen(e->name) + 1;
+        unsigned int e_len = DIRENTRY_SIZE(e_namelen);
+
+        direntry.e.flags = e->write ? XEN_HYPFS_WRITEABLE : 0;
+        direntry.e.type = e->type;
+        direntry.e.encoding = e->encoding;
+        direntry.e.content_len = e->size;
+        direntry.off_next = list_is_last(&e->list, &d->dirlist) ? 0 : e_len;
+        if ( copy_to_guest(uaddr, &direntry, 1) )
+            return -EFAULT;
+
+        if ( copy_to_guest_offset(uaddr, DIRENTRY_NAME_OFF,
+                                  e->name, e_namelen) )
+            return -EFAULT;
+
+        guest_handle_add_offset(uaddr, e_len);
+
+        ASSERT(e_len <= size);
+        size -= e_len;
+    }
+
+    return 0;
+}
+
+int hypfs_read_leaf(const struct hypfs_entry *entry,
+                    XEN_GUEST_HANDLE_PARAM(void) uaddr)
+{
+    const struct hypfs_entry_leaf *l;
+
+    l = container_of(entry, const struct hypfs_entry_leaf, e);
+
+    return copy_to_guest(uaddr, l->content, entry->size) ? -EFAULT: 0;
+}
+
+static int hypfs_read(const struct hypfs_entry *entry,
+                      XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen)
+{
+    struct xen_hypfs_direntry e;
+    long ret = -EINVAL;
+
+    if ( ulen < sizeof(e) )
+        goto out;
+
+    e.flags = entry->write ? XEN_HYPFS_WRITEABLE : 0;
+    e.type = entry->type;
+    e.encoding = entry->encoding;
+    e.content_len = entry->size;
+
+    ret = -EFAULT;
+    if ( copy_to_guest(uaddr, &e, 1) )
+        goto out;
+
+    ret = 0;
+    if ( ulen < entry->size + sizeof(e) )
+        goto out;
+
+    guest_handle_add_offset(uaddr, sizeof(e));
+
+    ret = entry->read(entry, uaddr);
+
+ out:
+    return ret;
+}
+
+int hypfs_write_leaf(struct hypfs_entry_leaf *leaf,
+                     XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen)
+{
+    char *buf;
+    int ret;
+
+    if ( ulen > leaf->e.size )
+        ulen = leaf->e.size;
+
+    buf = xzalloc_array(char, ulen);
+    if ( !buf )
+        return -ENOMEM;
+
+    ret = -EFAULT;
+    if ( copy_from_guest(buf, uaddr, ulen) )
+        goto out;
+
+    ret = 0;
+    if ( leaf->e.type == XEN_HYPFS_TYPE_STRING )
+        buf[leaf->e.size - 1] = 0;
+    memcpy(leaf->write_ptr, buf, ulen);
+
+ out:
+    xfree(buf);
+    return ret;
+}
+
+int hypfs_write_bool(struct hypfs_entry_leaf *leaf,
+                     XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen)
+{
+    union {
+        char buf[8];
+        uint8_t u8;
+        uint16_t u16;
+        uint32_t u32;
+        uint64_t u64;
+    } u;
+
+    ASSERT(leaf->e.type == XEN_HYPFS_TYPE_UINT && leaf->e.size <= 8);
+
+    if ( ulen != leaf->e.size )
+        return -EDOM;
+
+    if ( copy_from_guest(u.buf, uaddr, ulen) )
+        return -EFAULT;
+
+    switch ( leaf->e.size )
+    {
+    case 1:
+        *(uint8_t *)leaf->write_ptr = !!u.u8;
+        break;
+    case 2:
+        *(uint16_t *)leaf->write_ptr = !!u.u16;
+        break;
+    case 4:
+        *(uint32_t *)leaf->write_ptr = !!u.u32;
+        break;
+    case 8:
+        *(uint64_t *)leaf->write_ptr = !!u.u64;
+        break;
+    }
+
+    return 0;
+}
+
+static int hypfs_write(struct hypfs_entry *entry,
+                       XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen)
+{
+    struct hypfs_entry_leaf *l;
+
+    if ( !entry->write )
+        return -EACCES;
+
+    l = container_of(entry, struct hypfs_entry_leaf, e);
+
+    return entry->write(l, uaddr, ulen);
+}
+
+long do_hypfs_op(unsigned int cmd,
+                 XEN_GUEST_HANDLE_PARAM(void) arg1, unsigned long arg2,
+                 XEN_GUEST_HANDLE_PARAM(void) arg3, unsigned long arg4)
+{
+    int ret;
+    struct hypfs_entry *entry;
+    static char path[XEN_HYPFS_MAX_PATHLEN];
+
+    if ( !is_control_domain(current->domain) &&
+         !is_hardware_domain(current->domain) )
+        return -EPERM;
+
+    if ( cmd == XEN_HYPFS_OP_get_version )
+        return XEN_HYPFS_VERSION;
+
+    if ( cmd == XEN_HYPFS_OP_write_contents )
+        write_lock(&hypfs_lock);
+    else
+        read_lock(&hypfs_lock);
+
+    ret = hypfs_get_path_user(path, arg1, arg2);
+    if ( ret )
+        goto out;
+
+    entry = hypfs_get_entry(path);
+    if ( !entry )
+    {
+        ret = -ENOENT;
+        goto out;
+    }
+
+    switch ( cmd )
+    {
+    case XEN_HYPFS_OP_read_contents:
+        ret = hypfs_read(entry, arg3, arg4);
+        break;
+
+    case XEN_HYPFS_OP_write_contents:
+        ret = hypfs_write(entry, arg3, arg4);
+        break;
+
+    default:
+        ret = -ENOSYS;
+        break;
+    }
+
+ out:
+    if ( cmd == XEN_HYPFS_OP_write_contents )
+        write_unlock(&hypfs_lock);
+    else
+        read_unlock(&hypfs_lock);
+
+    return ret;
+}
diff --git a/xen/include/public/hypfs.h b/xen/include/public/hypfs.h
new file mode 100644
index 0000000000..8351511227
--- /dev/null
+++ b/xen/include/public/hypfs.h
@@ -0,0 +1,124 @@
+/******************************************************************************
+ * Xen Hypervisor Filesystem
+ *
+ * Copyright (c) 2019, SUSE Software Solutions Germany GmbH
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __XEN_PUBLIC_HYPFS_H__
+#define __XEN_PUBLIC_HYPFS_H__
+
+#include "xen.h"
+
+/*
+ * Definitions for the __HYPERVISOR_hypfs_op hypercall.
+ */
+
+/* Highest version number of the hypfs interface currently defined. */
+#define XEN_HYPFS_VERSION      1
+
+/* Maximum length of a path in the filesystem. */
+#define XEN_HYPFS_MAX_PATHLEN 1024
+
+struct xen_hypfs_direntry {
+    uint16_t flags;
+#define XEN_HYPFS_WRITEABLE    0x0001
+    uint8_t type;
+#define XEN_HYPFS_TYPE_DIR     0x0000
+#define XEN_HYPFS_TYPE_BLOB    0x0001
+#define XEN_HYPFS_TYPE_STRING  0x0002
+#define XEN_HYPFS_TYPE_UINT    0x0003
+#define XEN_HYPFS_TYPE_INT     0x0004
+#define XEN_HYPFS_TYPE_BOOL    0x0005
+    uint8_t encoding;
+#define XEN_HYPFS_ENC_PLAIN    0x0000
+#define XEN_HYPFS_ENC_GZIP     0x0001
+    uint32_t content_len;
+};
+
+struct xen_hypfs_dirlistentry {
+    struct xen_hypfs_direntry e;
+    /* Offset in bytes to next entry (0 == this is the last entry). */
+    uint16_t off_next;
+    char name[XEN_FLEX_ARRAY_DIM];
+};
+
+/*
+ * Hypercall operations.
+ */
+
+/*
+ * XEN_HYPFS_OP_get_version
+ *
+ * Read highest interface version supported by the hypervisor.
+ *
+ * Possible return values:
+ * >0: highest supported interface version
+ * <0: negative Xen errno value
+ */
+#define XEN_HYPFS_OP_get_version     0
+
+/*
+ * XEN_HYPFS_OP_read_contents
+ *
+ * Read contents of a filesystem entry.
+ *
+ * Returns the direntry and contents of an entry in the buffer supplied by the
+ * caller (struct xen_hypfs_direntry with the contents following directly
+ * after it).
+ * The data buffer must be at least the size of the direntry returned in order
+ * to have success. If the data buffer was not large enough for all the data
+ * no entry data is returned, but the direntry will contain the needed size
+ * for the returned data.
+ * The format of the contents is according to its entry type and encoding.
+ *
+ * arg1: XEN_GUEST_HANDLE(path name)
+ * arg2: length of path name (including trailing zero byte)
+ * arg3: XEN_GUEST_HANDLE(data buffer written by hypervisor)
+ * arg4: data buffer size
+ *
+ * Possible return values:
+ * 0: success (at least the direntry was returned)
+ * <0 : negative Xen errno value
+ */
+#define XEN_HYPFS_OP_read_contents     1
+
+/*
+ * XEN_HYPFS_OP_write_contents
+ *
+ * Write contents of a filesystem entry.
+ *
+ * Writes an entry with the contents of a buffer supplied by the caller.
+ * The data type and encoding can't be changed. The size can be changed only
+ * for blobs and strings.
+ *
+ * arg1: XEN_GUEST_HANDLE(path name)
+ * arg2: length of path name (including trailing zero byte)
+ * arg3: XEN_GUEST_HANDLE(content buffer read by hypervisor)
+ * arg4: content buffer size
+ *
+ * Possible return values:
+ * 0: success
+ * <0 : negative Xen errno value
+ */
+#define XEN_HYPFS_OP_write_contents    2
+
+#endif /* __XEN_PUBLIC_HYPFS_H__ */
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index d2198dffad..bf80f1da8c 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -130,6 +130,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
 #define __HYPERVISOR_argo_op              39
 #define __HYPERVISOR_xenpmu_op            40
 #define __HYPERVISOR_dm_op                41
+#define __HYPERVISOR_hypfs_op             42
 
 /* Architecture-specific hypercall definitions. */
 #define __HYPERVISOR_arch_0               48
diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
index ad8ad27b23..349a0f6487 100644
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -150,6 +150,14 @@ do_dm_op(
     unsigned int nr_bufs,
     XEN_GUEST_HANDLE_PARAM(xen_dm_op_buf_t) bufs);
 
+extern long
+do_hypfs_op(
+    unsigned int cmd,
+    XEN_GUEST_HANDLE_PARAM(void) arg1,
+    unsigned long arg2,
+    XEN_GUEST_HANDLE_PARAM(void) arg3,
+    unsigned long arg4);
+
 #ifdef CONFIG_COMPAT
 
 extern int
diff --git a/xen/include/xen/hypfs.h b/xen/include/xen/hypfs.h
new file mode 100644
index 0000000000..a1c2140398
--- /dev/null
+++ b/xen/include/xen/hypfs.h
@@ -0,0 +1,89 @@
+#ifndef __XEN_HYPFS_H__
+#define __XEN_HYPFS_H__
+
+#include <xen/list.h>
+#include <xen/string.h>
+#include <public/hypfs.h>
+
+struct hypfs_entry_leaf;
+
+struct hypfs_entry {
+    unsigned short type;
+    unsigned short encoding;
+    unsigned int size;
+    const char *name;
+    struct list_head list;
+    int (*read)(const struct hypfs_entry *entry,
+                XEN_GUEST_HANDLE_PARAM(void) uaddr);
+    int (*write)(struct hypfs_entry_leaf *leaf,
+                 XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen);
+};
+
+struct hypfs_entry_leaf {
+    struct hypfs_entry e;
+    union {
+        const void *content;
+        void *write_ptr;
+    };
+};
+
+struct hypfs_entry_dir {
+    struct hypfs_entry e;
+    struct list_head dirlist;
+};
+
+#define HYPFS_DIR_INIT(var, nam)                \
+    struct hypfs_entry_dir var = {              \
+        .e.type = XEN_HYPFS_TYPE_DIR,           \
+        .e.encoding = XEN_HYPFS_ENC_PLAIN,      \
+        .e.name = nam,                          \
+        .e.size = 0,                            \
+        .e.list = LIST_HEAD_INIT(var.e.list),   \
+        .e.read = hypfs_read_dir,               \
+        .dirlist = LIST_HEAD_INIT(var.dirlist), \
+    }
+
+/* Content and size need to be set via hypfs_string_set(). */
+#define HYPFS_STRING_INIT(var, nam)             \
+    struct hypfs_entry_leaf var = {             \
+        .e.type = XEN_HYPFS_TYPE_STRING,        \
+        .e.encoding = XEN_HYPFS_ENC_PLAIN,      \
+        .e.name = nam,                          \
+        .e.read = hypfs_read_leaf,              \
+    }
+
+static inline void hypfs_string_set(struct hypfs_entry_leaf *leaf,
+                                    const char *str)
+{
+    leaf->content = str;
+    leaf->e.size = strlen(str) + 1;
+}
+
+#define HYPFS_UINT_INIT(var, nam, uint)         \
+    struct hypfs_entry_leaf var = {             \
+        .e.type = XEN_HYPFS_TYPE_UINT,          \
+        .e.encoding = XEN_HYPFS_ENC_PLAIN,      \
+        .e.name = nam,                          \
+        .e.size = sizeof(uint),                 \
+        .e.read = hypfs_read_leaf,              \
+        .content = &uint,                       \
+    }
+
+
+extern struct hypfs_entry_dir hypfs_root;
+
+struct hypfs_entry *hypfs_get_entry(const char *path);
+int hypfs_add_dir(struct hypfs_entry_dir *parent,
+                  struct hypfs_entry_dir *dir, bool nofault);
+int hypfs_add_leaf(struct hypfs_entry_dir *parent,
+                   struct hypfs_entry_leaf *leaf, bool nofault);
+int hypfs_read_dir(const struct hypfs_entry *entry,
+                   XEN_GUEST_HANDLE_PARAM(void) uaddr);
+int hypfs_read_leaf(const struct hypfs_entry *entry,
+                    XEN_GUEST_HANDLE_PARAM(void) uaddr);
+int hypfs_write_leaf(struct hypfs_entry_leaf *leaf,
+                     XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen);
+int hypfs_write_bool(struct hypfs_entry_leaf *leaf,
+                     XEN_GUEST_HANDLE_PARAM(void) uaddr, unsigned long ulen);
+
+#endif /* __XEN_HYPFS_H__ */
-- 
2.16.4


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