Translate "native" ACL structures into ext4 ACL structures when
reading or writing the ACL EAs.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
misc/fuse2fs.c | 253 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 248 insertions(+), 5 deletions(-)
diff --git a/misc/fuse2fs.c b/misc/fuse2fs.c
index 8be9070..317032c 100644
--- a/misc/fuse2fs.c
+++ b/misc/fuse2fs.c
@@ -18,6 +18,7 @@
# include <linux/xattr.h>
#endif
#include <sys/ioctl.h>
+#include <sys/acl.h>
#include <unistd.h>
#include <fuse.h>
#include "ext2fs/ext2fs.h"
@@ -43,6 +44,197 @@
# define FL_PUNCH_HOLE_FLAG (0)
#endif
+/* ACL translation stuff */
+/*
+ * 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 (h_sz < 0 || 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 (f_sz < 0 || 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;
+}
+
/*
* ext2_file_t contains a struct inode, so we can't leave files open.
* Use this as a proxy instead.
@@ -1837,6 +2029,28 @@ 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[] = {
+ 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),
+ XATTR_TRANSLATOR(NULL, NULL, NULL),
+};
+#undef XATTR_TRANSLATOR
+
static int op_getxattr(const char *path, const char *key, char *value,
size_t len)
{
@@ -1844,8 +2058,9 @@ static int op_getxattr(const char *path, const char *key, char *value,
struct fuse2fs *ff = (struct fuse2fs *)ctxt->private_data;
ext2_filsys fs = ff->fs;
struct ext2_xattr_handle *h;
- void *ptr;
- unsigned int plen;
+ struct xattr_translate *xt;
+ void *ptr, *cptr;
+ size_t plen, clen;
ext2_ino_t ino;
errcode_t err;
int ret = 0;
@@ -1885,6 +2100,17 @@ 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) {
@@ -1894,6 +2120,7 @@ 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);
@@ -2005,6 +2232,9 @@ static int op_setxattr(const char *path, const char *key, const char *value,
struct fuse2fs *ff = (struct fuse2fs *)ctxt->private_data;
ext2_filsys fs = ff->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;
@@ -2038,19 +2268,32 @@ 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)
--
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