libfrog: support editing filesystem property sets

Add some library functions so that spaceman and scrub can share the same
code to edit and retrieve filesystem properties.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/libfrog/Makefile b/libfrog/Makefile
index 0b5b23893a1304f5a2afade902421b17652f8152..acddc894ee9395d53a6a37dcd3d244b534a9fe42 100644 (file)
--- a/libfrog/Makefile
+++ b/libfrog/Makefile
@@ -20,6 +20,7 @@ convert.c \
 crc32.c \
 file_exchange.c \
 fsgeom.c \
+fsproperties.c \
 getparents.c \
 histogram.c \
 list_sort.c \
@@ -47,6 +48,7 @@ dahashselftest.h \
 div64.h \
 file_exchange.h \
 fsgeom.h \
+fsproperties.h \
 getparents.h \
 histogram.h \
 logging.h \
@@ -60,6 +62,11 @@ workqueue.h
 
 LSRCFILES += gen_crc32table.c
 
+ifeq ($(HAVE_LIBATTR),yes)
+CFILES+=fsprops.c
+HFILES+=fsprops.h
+endif
+
 LDIRT = gen_crc32table crc32table.h
 
 default: ltdepend $(LTLIBRARY)

diff --git a/libfrog/fsproperties.c b/libfrog/fsproperties.c
new file mode 100644 (file)
index 0000000..c317d15
--- /dev/null
+++ b/libfrog/fsproperties.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2024 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include <string.h>
+#include "xfs.h"
+#include "libfrog/fsgeom.h"
+#include "libfrog/fsproperties.h"
+#include "list.h"
+
+/* Return the offset of a string in a string table, or -1 if not found. */
+static inline int
+__fsprops_lookup(
+       const char      *values[],
+       unsigned int    nr_values,
+       const char      *value)
+{
+       unsigned int    i;
+
+       for (i = 0; i < nr_values; i++) {
+               if (values[i] && !strcmp(value, values[i]))
+                       return i;
+       }
+
+       return -1;
+}
+
+#define fsprops_lookup(values, value) \
+       __fsprops_lookup((values), ARRAY_SIZE(values), (value))
+
+/* Return true if a fs property name=value tuple is allowed. */
+bool
+fsprop_validate(
+       const char      *name,
+       const char      *value)
+{
+       return true;
+}

diff --git a/libfrog/fsproperties.h b/libfrog/fsproperties.h
new file mode 100644 (file)
index 0000000..6dee825
--- /dev/null
+++ b/libfrog/fsproperties.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2024 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#ifndef __LIBFROG_FSPROPERTIES_H__
+#define __LIBFROG_FSPROPERTIES_H__
+
+/* Name space for filesystem properties. */
+#define XFS_FSPROPS_NS         "trusted"
+
+/*
+ * All filesystem property xattr names must have this string after the
+ * namespace.  For example, the VFS xattr calls should use the name
+ * "trusted.xfs:fubar".  The xfs xattr ioctls would set ATTR_ROOT and use the
+ * name "xfs:fubar".
+ */
+#define XFS_FSPROPS_PREFIX     "xfs:"
+
+static inline int
+fsprop_name_to_attr_name(
+       const char              *prop_name,
+       char                    **attr_name)
+{
+       return asprintf(attr_name, XFS_FSPROPS_PREFIX "%s", prop_name);
+}
+
+static inline const char *
+attr_name_to_fsprop_name(
+       const char              *attr_name)
+{
+       const size_t            bytes = sizeof(XFS_FSPROPS_PREFIX) - 1;
+       unsigned int            i;
+
+       for (i = 0; i < bytes; i++) {
+               if (attr_name[i] == 0)
+                       return NULL;
+       }
+
+       if (memcmp(attr_name, XFS_FSPROPS_PREFIX, bytes) != 0)
+               return NULL;
+
+       return attr_name + bytes;
+}
+
+bool fsprop_validate(const char *name, const char *value);
+
+/* Specific Filesystem Properties */
+
+#endif /* __LIBFROG_FSPROPERTIES_H__ */

diff --git a/libfrog/fsprops.c b/libfrog/fsprops.c
new file mode 100644 (file)
index 0000000..d6d143e
--- /dev/null
+++ b/libfrog/fsprops.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2024 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "xfs.h"
+#include "handle.h"
+#include "libfrog/fsgeom.h"
+#include "libfrog/paths.h"
+#include "libfrog/bulkstat.h"
+#include "libfrog/fsprops.h"
+#include "libfrog/fsproperties.h"
+
+#include <attr/attributes.h>
+
+/*
+ * Given an xfd and a mount table path, get us the handle for the root dir so
+ * we can set filesystem properties.
+ */
+int
+fsprops_open_handle(
+       struct xfs_fd           *xfd,
+       struct fs_path          *fs_path,
+       struct fsprops_handle   *fph)
+{
+       struct xfs_bulkstat     bulkstat;
+       struct stat             sb;
+       int                     fd;
+       int                     ret;
+
+       /* fs properties only supported on V5 filesystems */
+       if (!(xfd->fsgeom.flags & XFS_FSOP_GEOM_FLAGS_V5SB)) {
+               errno = EOPNOTSUPP;
+               return -1;
+       }
+
+       ret = -xfrog_bulkstat_single(xfd, XFS_BULK_IREQ_SPECIAL_ROOT,
+                       XFS_BULK_IREQ_SPECIAL, &bulkstat);
+       if (ret)
+               return ret;
+
+       fd = open(fs_path->fs_dir, O_RDONLY | O_DIRECTORY);
+       if (fd < 0)
+               return -1;
+
+       ret = fstat(fd, &sb);
+       if (ret)
+               goto out_fd;
+
+       if (sb.st_ino != bulkstat.bs_ino) {
+               errno = ESRMNT;
+               ret = -1;
+               goto out_fd;
+       }
+
+       ret = fd_to_handle(fd, &fph->hanp, &fph->hlen);
+       if (ret)
+               goto out_fd;
+
+out_fd:
+       close(fd);
+       return ret;
+}
+
+/* Free a fsproperties handle. */
+void
+fsprops_free_handle(
+       struct fsprops_handle   *fph)
+{
+       if (fph->hanp)
+               free_handle(fph->hanp, fph->hlen);
+       fph->hanp = NULL;
+       fph->hlen = 0;
+}
+
+/* Call the given callback on every fs property accessible through the handle. */
+int
+fsprops_walk_names(
+       struct fsprops_handle   *fph,
+       fsprops_name_walk_fn    walk_fn,
+       void                    *priv)
+{
+       struct attrlist_cursor  cur = { };
+       char                    attrbuf[XFS_XATTR_LIST_MAX];
+       struct attrlist         *attrlist = (struct attrlist *)attrbuf;
+       int                     ret;
+
+       memset(attrbuf, 0, XFS_XATTR_LIST_MAX);
+
+       while ((ret = attr_list_by_handle(fph->hanp, fph->hlen, attrbuf,
+                               XFS_XATTR_LIST_MAX, XFS_IOC_ATTR_ROOT,
+                               &cur)) == 0) {
+               unsigned int    i;
+
+               for (i = 0; i < attrlist->al_count; i++) {
+                       struct attrlist_ent     *ent = ATTR_ENTRY(attrlist, i);
+                       const char              *p =
+                               attr_name_to_fsprop_name(ent->a_name);
+
+                       if (p) {
+                               ret = walk_fn(fph, p, ent->a_valuelen, priv);
+                               if (ret)
+                                       break;
+                       }
+               }
+
+               if (!attrlist->al_more)
+                       break;
+       }
+
+       return ret;
+}
+
+/* Retrieve the value of a specific fileystem property. */
+int
+fsprops_get(
+       struct fsprops_handle   *fph,
+       const char              *name,
+       void                    *valuebuf,
+       size_t                  *valuelen)
+{
+       struct xfs_attr_multiop ops = {
+               .am_opcode      = ATTR_OP_GET,
+               .am_attrvalue   = valuebuf,
+               .am_length      = *valuelen,
+               .am_flags       = XFS_IOC_ATTR_ROOT,
+       };
+       int                     ret;
+
+       ret = fsprop_name_to_attr_name(name, (char **)&ops.am_attrname);
+       if (ret < 0)
+               return ret;
+
+       ret = attr_multi_by_handle(fph->hanp, fph->hlen, &ops, 1, 0);
+       if (ret < 0)
+               goto out_name;
+
+       if (ops.am_error) {
+               errno = -ops.am_error;
+               ret = -1;
+               goto out_name;
+       }
+
+       *valuelen = ops.am_length;
+out_name:
+       free(ops.am_attrname);
+       return ret;
+}
+
+/* Set the value of a specific fileystem property. */
+int
+fsprops_set(
+       struct fsprops_handle   *fph,
+       const char              *name,
+       void                    *valuebuf,
+       size_t                  valuelen)
+{
+       struct xfs_attr_multiop ops = {
+               .am_opcode      = ATTR_OP_SET,
+               .am_attrvalue   = valuebuf,
+               .am_length      = valuelen,
+               .am_flags       = XFS_IOC_ATTR_ROOT,
+       };
+       int                     ret;
+
+       ret = fsprop_name_to_attr_name(name, (char **)&ops.am_attrname);
+       if (ret < 0)
+               return ret;
+
+       ret = attr_multi_by_handle(fph->hanp, fph->hlen, &ops, 1, 0);
+       if (ret < 0)
+               goto out_name;
+
+       if (ops.am_error) {
+               errno = -ops.am_error;
+               ret = -1;
+               goto out_name;
+       }
+
+out_name:
+       free(ops.am_attrname);
+       return ret;
+}
+
+/* Unset the value of a specific fileystem property. */
+int
+fsprops_remove(
+       struct fsprops_handle   *fph,
+       const char              *name)
+{
+       struct xfs_attr_multiop ops = {
+               .am_opcode      = ATTR_OP_REMOVE,
+               .am_flags       = XFS_IOC_ATTR_ROOT,
+       };
+       int                     ret;
+
+       ret = fsprop_name_to_attr_name(name, (char **)&ops.am_attrname);
+       if (ret < 0)
+               return ret;
+
+       ret = attr_multi_by_handle(fph->hanp, fph->hlen, &ops, 1, 0);
+       if (ret < 0)
+               goto out_name;
+
+       if (ops.am_error) {
+               errno = -ops.am_error;
+               ret = -1;
+               goto out_name;
+       }
+
+out_name:
+       free(ops.am_attrname);
+       return ret;
+}

diff --git a/libfrog/fsprops.h b/libfrog/fsprops.h
new file mode 100644 (file)
index 0000000..9276f24
--- /dev/null
+++ b/libfrog/fsprops.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2024 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#ifndef __LIBFROG_FSPROPS_H__
+#define __LIBFROG_FSPROPS_H__
+
+/* Edit and view filesystem property sets. */
+
+struct fsprops_handle {
+       void    *hanp;
+       size_t  hlen;
+};
+
+struct xfs_fd;
+struct fs_path;
+
+int fsprops_open_handle(struct xfs_fd *xfd, struct fs_path *fspath,
+               struct fsprops_handle *fph);
+void fsprops_free_handle(struct fsprops_handle *fph);
+
+typedef int (*fsprops_name_walk_fn)(struct fsprops_handle *fph,
+               const char *name, size_t valuelen, void *priv);
+
+int fsprops_walk_names(struct fsprops_handle *fph, fsprops_name_walk_fn walk_fn,
+               void *priv);
+int fsprops_get(struct fsprops_handle *fph, const char *name, void *attrbuf,
+               size_t *attrlen);
+int fsprops_set(struct fsprops_handle *fph, const char *name, void *attrbuf,
+               size_t attrlen);
+int fsprops_remove(struct fsprops_handle *fph, const char *name);
+
+#endif /* __LIBFROG_FSPROPS_H__ */