[PATCH 31/37] fuse2fs: translate ACL structures

Darrick J. Wong
2014-05-01T23:15:51Z

Translate "native" ACL structures into ext4 ACL structures when
reading or writing the ACL EAs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
configure | 5 +
configure.in | 8 +-
lib/config.h.in | 3 +
misc/fuse2fs.c | 262 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
4 files changed, 270 insertions(+), 8 deletions(-)

diff --git a/configure b/configure
index ce6a4ef..e5943af 100755
--- a/configure
+++ b/configure
@@ -10479,7 +10479,7 @@ fi
done

fi
-for ac_header in dirent.h errno.h execinfo.h getopt.h malloc.h mntent.h paths.h semaphore.h setjmp.h signal.h stdarg.h stdint.h stdlib.h termios.h termio.h unistd.h utime.h linux/falloc.h linux/fd.h linux/major.h linux/loop.h net/if_dl.h netinet/in.h sys/disklabel.h sys/file.h sys/ioctl.h sys/mkdev.h sys/mman.h sys/prctl.h sys/queue.h sys/resource.h sys/select.h sys/socket.h sys/sockio.h sys/stat.h sys/syscall.h sys/sysctl.h sys/sysmacros.h sys/time.h sys/types.h sys/un.h sys/wait.h
+for ac_header in dirent.h errno.h execinfo.h getopt.h malloc.h mntent.h paths.h semaphore.h setjmp.h signal.h stdarg.h stdint.h stdlib.h termios.h termio.h unistd.h utime.h linux/falloc.h linux/fd.h linux/major.h linux/loop.h net/if_dl.h netinet/in.h sys/acl.h sys/disklabel.h sys/file.h sys/ioctl.h sys/mkdev.h sys/mman.h sys/prctl.h sys/queue.h sys/resource.h sys/select.h sys/socket.h sys/sockio.h sys/stat.h sys/syscall.h sys/sysctl.h sys/sysmacros.h sys/time.h sys/types.h sys/un.h sys/wait.h
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
@@ -11228,6 +11228,7 @@ else
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
ac_fn_c_check_header_compile "$LINENO" "$ac_header" "$as_ac_Header" "#define _FILE_OFFSET_BITS 64
+#define FUSE_USE_VERSION 29
"
if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
cat >>confdefs.h <<_ACEOF
@@ -11246,6 +11247,7 @@ done

cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
+#define FUSE_USE_VERSION 29
#ifdef __linux__
#include <linux/fs.h>
#include <linux/falloc.h>
@@ -11365,6 +11367,7 @@ else
do :
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
ac_fn_c_check_header_compile "$LINENO" "$ac_header" "$as_ac_Header" "#define _FILE_OFFSET_BITS 64
+#define FUSE_USE_VERSION 29
#ifdef __linux__
# include <linux/fs.h>
# include <linux/falloc.h>
diff --git a/configure.in b/configure.in
index 2c455af..6c185e7 100644
--- a/configure.in
+++ b/configure.in
@@ -948,6 +948,7 @@ AC_CHECK_HEADERS(m4_flatten([
linux/loop.h
net/if_dl.h
netinet/in.h
+ sys/acl.h
sys/disklabel.h
sys/file.h
sys/ioctl.h
@@ -1177,10 +1178,12 @@ then
else
AC_CHECK_HEADERS([pthread.h fuse.h], [],
[AC_MSG_FAILURE([Cannot find fuse2fs headers.])],
-[#define _FILE_OFFSET_BITS 64])
+[#define _FILE_OFFSET_BITS 64
+#define FUSE_USE_VERSION 29])

AC_PREPROC_IFELSE(
-[AC_LANG_PROGRAM([[#ifdef __linux__
+[AC_LANG_PROGRAM([[#define FUSE_USE_VERSION 29
+#ifdef __linux__
#include <linux/fs.h>
#include <linux/falloc.h>
#include <linux/xattr.h>
@@ -1195,6 +1198,7 @@ fi
,
AC_CHECK_HEADERS([pthread.h fuse.h], [], [FUSE_CMT="#"],
[#define _FILE_OFFSET_BITS 64
+#define FUSE_USE_VERSION 29
#ifdef __linux__
# include <linux/fs.h>
# include <linux/falloc.h>
diff --git a/lib/config.h.in b/lib/config.h.in
index 118a508..852c305 100644
--- a/lib/config.h.in
+++ b/lib/config.h.in
@@ -426,6 +426,9 @@
/* Define to 1 if you have the `sysconf' function. */
#undef HAVE_SYSCONF

+/* Define to 1 if you have the <sys/acl.h> header file. */
+#undef HAVE_SYS_ACL_H
+
/* Define to 1 if you have the <sys/disklabel.h> header file. */
#undef HAVE_SYS_DISKLABEL_H

diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index dbb9048..93b4b90 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -17,9 +17,15 @@
# include <linux/falloc.h>
# include <linux/xattr.h>
# define FUSE_PLATFORM_OPTS ",nonempty,big_writes"
+# ifdef HAVE_SYS_ACL_H
+# define TRANSLATE_LINUX_ACLS
+# endif
#else
# define FUSE_PLATFORM_OPTS ""
#endif
+#ifdef TRANSLATE_LINUX_ACLS
+# include <sys/acl.h>
+#endif
#include <sys/ioctl.h>
#include <unistd.h>
#include <fuse.h>
@@ -59,6 +65,199 @@ static ext2_filsys global_fs; /* Try not to use this directly */
# define FL_PUNCH_HOLE_FLAG (0)
#endif

+/* ACL translation stuff */
+#ifdef TRANSLATE_LINUX_ACLS
+/*
+ * Copied from acl_ea.h in libacl source; ACLs have to be sent to and from fuse
+ * in this format... at least on Linux.
+ */
+#define ACL_EA_ACCESS "system.posix_acl_access"
+#define ACL_EA_DEFAULT "system.posix_acl_default"
+
+#define ACL_EA_VERSION 0x0002
+
+typedef struct {
+ u_int16_t e_tag;
+ u_int16_t e_perm;
+ u_int32_t e_id;
+} acl_ea_entry;
+
+typedef struct {
+ u_int32_t a_version;
+ acl_ea_entry a_entries[0];
+} acl_ea_header;
+
+static inline size_t acl_ea_size(int count)
+{
+ return sizeof(acl_ea_header) + count * sizeof(acl_ea_entry);
+}
+
+static inline int acl_ea_count(size_t size)
+{
+ if (size < sizeof(acl_ea_header))
+ return -1;
+ size -= sizeof(acl_ea_header);
+ if (size % sizeof(acl_ea_entry))
+ return -1;
+ return size / sizeof(acl_ea_entry);
+}
+
+/*
+ * ext4 ACL structures, copied from fs/ext4/acl.h.
+ */
+#define EXT4_ACL_VERSION 0x0001
+
+typedef struct {
+ __u16 e_tag;
+ __u16 e_perm;
+ __u32 e_id;
+} ext4_acl_entry;
+
+typedef struct {
+ __u16 e_tag;
+ __u16 e_perm;
+} ext4_acl_entry_short;
+
+typedef struct {
+ __u32 a_version;
+} ext4_acl_header;
+
+static inline size_t ext4_acl_size(int count)
+{
+ if (count <= 4) {
+ return sizeof(ext4_acl_header) +
+ count * sizeof(ext4_acl_entry_short);
+ } else {
+ return sizeof(ext4_acl_header) +
+ 4 * sizeof(ext4_acl_entry_short) +
+ (count - 4) * sizeof(ext4_acl_entry);
+ }
+}
+
+static inline int ext4_acl_count(size_t size)
+{
+ ssize_t s;
+ size -= sizeof(ext4_acl_header);
+ s = size - 4 * sizeof(ext4_acl_entry_short);
+ if (s < 0) {
+ if (size % sizeof(ext4_acl_entry_short))
+ return -1;
+ return size / sizeof(ext4_acl_entry_short);
+ } else {
+ if (s % sizeof(ext4_acl_entry))
+ return -1;
+ return s / sizeof(ext4_acl_entry) + 4;
+ }
+}
+
+static errcode_t fuse_to_ext4_acl(acl_ea_header *facl, size_t facl_sz,
+ ext4_acl_header **eacl, size_t *eacl_sz)
+{
+ int i, facl_count;
+ ext4_acl_header *h;
+ size_t h_sz;
+ ext4_acl_entry *e;
+ acl_ea_entry *a;
+ void *hptr;
+ errcode_t err;
+
+ facl_count = acl_ea_count(facl_sz);
+ h_sz = ext4_acl_size(facl_count);
+ if (facl_count < 0 || facl->a_version != ACL_EA_VERSION)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ err = ext2fs_get_mem(h_sz, &h);
+ if (err)
+ return err;
+
+ h->a_version = ext2fs_cpu_to_le32(EXT4_ACL_VERSION);
+ hptr = h + 1;
+ for (i = 0, a = facl->a_entries; i < facl_count; i++, a++) {
+ e = hptr;
+ e->e_tag = ext2fs_cpu_to_le16(a->e_tag);
+ e->e_perm = ext2fs_cpu_to_le16(a->e_perm);
+
+ switch (a->e_tag) {
+ case ACL_USER:
+ case ACL_GROUP:
+ e->e_id = ext2fs_cpu_to_le32(a->e_id);
+ hptr += sizeof(ext4_acl_entry);
+ break;
+ case ACL_USER_OBJ:
+ case ACL_GROUP_OBJ:
+ case ACL_MASK:
+ case ACL_OTHER:
+ hptr += sizeof(ext4_acl_entry_short);
+ break;
+ default:
+ err = EXT2_ET_INVALID_ARGUMENT;
+ goto out;
+ }
+ }
+
+ *eacl = h;
+ *eacl_sz = h_sz;
+ return err;
+out:
+ ext2fs_free_mem(&h);
+ return err;
+}
+
+static errcode_t ext4_to_fuse_acl(acl_ea_header **facl, size_t *facl_sz,
+ ext4_acl_header *eacl, size_t eacl_sz)
+{
+ int i, eacl_count;
+ acl_ea_header *f;
+ ext4_acl_entry *e;
+ acl_ea_entry *a;
+ size_t f_sz;
+ void *hptr;
+ errcode_t err;
+
+ eacl_count = ext4_acl_count(eacl_sz);
+ f_sz = acl_ea_size(eacl_count);
+ if (eacl_count < 0 ||
+ eacl->a_version != ext2fs_cpu_to_le32(EXT4_ACL_VERSION))
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ err = ext2fs_get_mem(f_sz, &f);
+ if (err)
+ return err;
+
+ f->a_version = ACL_EA_VERSION;
+ hptr = eacl + 1;
+ for (i = 0, a = f->a_entries; i < eacl_count; i++, a++) {
+ e = hptr;
+ a->e_tag = ext2fs_le16_to_cpu(e->e_tag);
+ a->e_perm = ext2fs_le16_to_cpu(e->e_perm);
+
+ switch (a->e_tag) {
+ case ACL_USER:
+ case ACL_GROUP:
+ a->e_id = ext2fs_le32_to_cpu(e->e_id);
+ hptr += sizeof(ext4_acl_entry);
+ break;
+ case ACL_USER_OBJ:
+ case ACL_GROUP_OBJ:
+ case ACL_MASK:
+ case ACL_OTHER:
+ hptr += sizeof(ext4_acl_entry_short);
+ break;
+ default:
+ err = EXT2_ET_INVALID_ARGUMENT;
+ goto out;
+ }
+ }
+
+ *facl = f;
+ *facl_sz = f_sz;
+ return err;
+out:
+ ext2fs_free_mem(&f);
+ return err;
+}
+#endif /* TRANSLATE_LINUX_ACLS */
+
/*
* ext2_file_t contains a struct inode, so we can't leave files open.
* Use this as a proxy instead.
@@ -2115,6 +2314,30 @@ static int op_statfs(const char *path, struct statvfs *buf)
return 0;
}

+typedef errcode_t (*xattr_xlate_get)(void **cooked_buf, size_t *cooked_sz,
+ const void *raw_buf, size_t raw_sz);
+typedef errcode_t (*xattr_xlate_set)(const void *cooked_buf, size_t cooked_sz,
+ void **raw_buf, size_t *raw_sz);
+struct xattr_translate {
+ const char *prefix;
+ xattr_xlate_get get;
+ xattr_xlate_set set;
+};
+
+#define XATTR_TRANSLATOR(p, g, s) \
+ {.prefix = (p), \
+ .get = (xattr_xlate_get)(g), \
+ .set = (xattr_xlate_set)(s)}
+
+static struct xattr_translate xattr_translators[] = {
+#ifdef TRANSLATE_LINUX_ACLS
+ XATTR_TRANSLATOR(ACL_EA_ACCESS, ext4_to_fuse_acl, fuse_to_ext4_acl),
+ XATTR_TRANSLATOR(ACL_EA_DEFAULT, ext4_to_fuse_acl, fuse_to_ext4_acl),
+#endif
+ XATTR_TRANSLATOR(NULL, NULL, NULL),
+};
+#undef XATTR_TRANSLATOR
+
static int op_getxattr(const char *path, const char *key, char *value,
size_t len)
{
@@ -2122,8 +2345,9 @@ static int op_getxattr(const char *path, const char *key, char *value,
struct fuse2fs *ff = (struct fuse2fs *)ctxt->private_data;
ext2_filsys fs;
struct ext2_xattr_handle *h;
- void *ptr;
- size_t plen;
+ struct xattr_translate *xt;
+ void *ptr, *cptr;
+ size_t plen, clen;
ext2_ino_t ino;
errcode_t err;
int ret = 0;
@@ -2166,6 +2390,17 @@ static int op_getxattr(const char *path, const char *key, char *value,
goto out2;
}

+ for (xt = xattr_translators; xt->prefix != NULL; xt++) {
+ if (strncmp(key, xt->prefix, strlen(xt->prefix)) == 0) {
+ err = xt->get(&cptr, &clen, ptr, plen);
+ if (err)
+ goto out3;
+ ext2fs_free_mem(&ptr);
+ ptr = cptr;
+ plen = clen;
+ }
+ }
+
if (!len) {
ret = plen;
} else if (len < plen) {
@@ -2175,6 +2410,7 @@ static int op_getxattr(const char *path, const char *key, char *value,
ret = plen;
}

+out3:
ext2fs_free_mem(&ptr);
out2:
err = ext2fs_xattrs_close(&h);
@@ -2289,6 +2525,9 @@ static int op_setxattr(const char *path, const char *key, const char *value,
struct fuse2fs *ff = (struct fuse2fs *)ctxt->private_data;
ext2_filsys fs;
struct ext2_xattr_handle *h;
+ struct xattr_translate *xt;
+ void *cvalue;
+ size_t clen;
ext2_ino_t ino;
errcode_t err;
int ret = 0;
@@ -2328,19 +2567,32 @@ static int op_setxattr(const char *path, const char *key, const char *value,
goto out2;
}

- err = ext2fs_xattr_set(h, key, value, len);
+ cvalue = (void *)value;
+ clen = len;
+ for (xt = xattr_translators; xt->prefix != NULL; xt++) {
+ if (strncmp(key, xt->prefix, strlen(xt->prefix)) == 0) {
+ err = xt->set(value, len, &cvalue, &clen);
+ if (err)
+ goto out3;
+ }
+ }
+
+ err = ext2fs_xattr_set(h, key, cvalue, clen);
if (err) {
ret = translate_error(fs, ino, err);
- goto out2;
+ goto out3;
}

err = ext2fs_xattrs_write(h);
if (err) {
ret = translate_error(fs, ino, err);
- goto out2;
+ goto out3;
}

ret = update_ctime(fs, ino, NULL);
+out3:
+ if (cvalue != value)
+ ext2fs_free_mem(&cvalue);
out2:
err = ext2fs_xattrs_close(&h);
if (!ret && err)