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author | Arnd Bergmann <arnd@arndb.de> | 2011-10-20 15:14:25 +0200 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2011-10-20 15:14:25 +0200 |
commit | b4cbb8a4e602ea77b0525d06eff89c6a6070dab3 (patch) | |
tree | a5dd723679582505ef3905c90f0c2c032d191b94 /fs/xfs/xfs_acl.c | |
parent | 526b264163068f77c5f2409031f5e25caf3900a9 (diff) | |
parent | c5d7a9230e5e277f262b6806b7f4d6b35de5a3fb (diff) | |
download | linux-b4cbb8a4e602ea77b0525d06eff89c6a6070dab3.tar.bz2 |
Merge branch 'imx-features-for-arnd' of git://git.pengutronix.de/git/imx/linux-2.6 into imx/devel
Conflicts:
arch/arm/mach-mx5/clock-mx51-mx53.c
arch/arm/mach-mx5/devices-imx53.h
Diffstat (limited to 'fs/xfs/xfs_acl.c')
-rw-r--r-- | fs/xfs/xfs_acl.c | 420 |
1 files changed, 420 insertions, 0 deletions
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c new file mode 100644 index 000000000000..b6c4b3795c4a --- /dev/null +++ b/fs/xfs/xfs_acl.c @@ -0,0 +1,420 @@ +/* + * Copyright (c) 2008, Christoph Hellwig + * All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include "xfs.h" +#include "xfs_acl.h" +#include "xfs_attr.h" +#include "xfs_bmap_btree.h" +#include "xfs_inode.h" +#include "xfs_vnodeops.h" +#include "xfs_trace.h" +#include <linux/slab.h> +#include <linux/xattr.h> +#include <linux/posix_acl_xattr.h> + + +/* + * Locking scheme: + * - all ACL updates are protected by inode->i_mutex, which is taken before + * calling into this file. + */ + +STATIC struct posix_acl * +xfs_acl_from_disk(struct xfs_acl *aclp) +{ + struct posix_acl_entry *acl_e; + struct posix_acl *acl; + struct xfs_acl_entry *ace; + int count, i; + + count = be32_to_cpu(aclp->acl_cnt); + + acl = posix_acl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + + for (i = 0; i < count; i++) { + acl_e = &acl->a_entries[i]; + ace = &aclp->acl_entry[i]; + + /* + * The tag is 32 bits on disk and 16 bits in core. + * + * Because every access to it goes through the core + * format first this is not a problem. + */ + acl_e->e_tag = be32_to_cpu(ace->ae_tag); + acl_e->e_perm = be16_to_cpu(ace->ae_perm); + + switch (acl_e->e_tag) { + case ACL_USER: + case ACL_GROUP: + acl_e->e_id = be32_to_cpu(ace->ae_id); + break; + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + acl_e->e_id = ACL_UNDEFINED_ID; + break; + default: + goto fail; + } + } + return acl; + +fail: + posix_acl_release(acl); + return ERR_PTR(-EINVAL); +} + +STATIC void +xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl) +{ + const struct posix_acl_entry *acl_e; + struct xfs_acl_entry *ace; + int i; + + aclp->acl_cnt = cpu_to_be32(acl->a_count); + for (i = 0; i < acl->a_count; i++) { + ace = &aclp->acl_entry[i]; + acl_e = &acl->a_entries[i]; + + ace->ae_tag = cpu_to_be32(acl_e->e_tag); + ace->ae_id = cpu_to_be32(acl_e->e_id); + ace->ae_perm = cpu_to_be16(acl_e->e_perm); + } +} + +struct posix_acl * +xfs_get_acl(struct inode *inode, int type) +{ + struct xfs_inode *ip = XFS_I(inode); + struct posix_acl *acl; + struct xfs_acl *xfs_acl; + int len = sizeof(struct xfs_acl); + unsigned char *ea_name; + int error; + + acl = get_cached_acl(inode, type); + if (acl != ACL_NOT_CACHED) + return acl; + + trace_xfs_get_acl(ip); + + switch (type) { + case ACL_TYPE_ACCESS: + ea_name = SGI_ACL_FILE; + break; + case ACL_TYPE_DEFAULT: + ea_name = SGI_ACL_DEFAULT; + break; + default: + BUG(); + } + + /* + * If we have a cached ACLs value just return it, not need to + * go out to the disk. + */ + + xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); + if (!xfs_acl) + return ERR_PTR(-ENOMEM); + + error = -xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl, + &len, ATTR_ROOT); + if (error) { + /* + * If the attribute doesn't exist make sure we have a negative + * cache entry, for any other error assume it is transient and + * leave the cache entry as ACL_NOT_CACHED. + */ + if (error == -ENOATTR) { + acl = NULL; + goto out_update_cache; + } + goto out; + } + + acl = xfs_acl_from_disk(xfs_acl); + if (IS_ERR(acl)) + goto out; + + out_update_cache: + set_cached_acl(inode, type, acl); + out: + kfree(xfs_acl); + return acl; +} + +STATIC int +xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl) +{ + struct xfs_inode *ip = XFS_I(inode); + unsigned char *ea_name; + int error; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + + switch (type) { + case ACL_TYPE_ACCESS: + ea_name = SGI_ACL_FILE; + break; + case ACL_TYPE_DEFAULT: + if (!S_ISDIR(inode->i_mode)) + return acl ? -EACCES : 0; + ea_name = SGI_ACL_DEFAULT; + break; + default: + return -EINVAL; + } + + if (acl) { + struct xfs_acl *xfs_acl; + int len; + + xfs_acl = kzalloc(sizeof(struct xfs_acl), GFP_KERNEL); + if (!xfs_acl) + return -ENOMEM; + + xfs_acl_to_disk(xfs_acl, acl); + len = sizeof(struct xfs_acl) - + (sizeof(struct xfs_acl_entry) * + (XFS_ACL_MAX_ENTRIES - acl->a_count)); + + error = -xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl, + len, ATTR_ROOT); + + kfree(xfs_acl); + } else { + /* + * A NULL ACL argument means we want to remove the ACL. + */ + error = -xfs_attr_remove(ip, ea_name, ATTR_ROOT); + + /* + * If the attribute didn't exist to start with that's fine. + */ + if (error == -ENOATTR) + error = 0; + } + + if (!error) + set_cached_acl(inode, type, acl); + return error; +} + +static int +xfs_set_mode(struct inode *inode, umode_t mode) +{ + int error = 0; + + if (mode != inode->i_mode) { + struct iattr iattr; + + iattr.ia_valid = ATTR_MODE | ATTR_CTIME; + iattr.ia_mode = mode; + iattr.ia_ctime = current_fs_time(inode->i_sb); + + error = -xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL); + } + + return error; +} + +static int +xfs_acl_exists(struct inode *inode, unsigned char *name) +{ + int len = sizeof(struct xfs_acl); + + return (xfs_attr_get(XFS_I(inode), name, NULL, &len, + ATTR_ROOT|ATTR_KERNOVAL) == 0); +} + +int +posix_acl_access_exists(struct inode *inode) +{ + return xfs_acl_exists(inode, SGI_ACL_FILE); +} + +int +posix_acl_default_exists(struct inode *inode) +{ + if (!S_ISDIR(inode->i_mode)) + return 0; + return xfs_acl_exists(inode, SGI_ACL_DEFAULT); +} + +/* + * No need for i_mutex because the inode is not yet exposed to the VFS. + */ +int +xfs_inherit_acl(struct inode *inode, struct posix_acl *acl) +{ + umode_t mode = inode->i_mode; + int error = 0, inherit = 0; + + if (S_ISDIR(inode->i_mode)) { + error = xfs_set_acl(inode, ACL_TYPE_DEFAULT, acl); + if (error) + goto out; + } + + error = posix_acl_create(&acl, GFP_KERNEL, &mode); + if (error < 0) + return error; + + /* + * If posix_acl_create returns a positive value we need to + * inherit a permission that can't be represented using the Unix + * mode bits and we actually need to set an ACL. + */ + if (error > 0) + inherit = 1; + + error = xfs_set_mode(inode, mode); + if (error) + goto out; + + if (inherit) + error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl); + +out: + posix_acl_release(acl); + return error; +} + +int +xfs_acl_chmod(struct inode *inode) +{ + struct posix_acl *acl; + int error; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + + acl = xfs_get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl) || !acl) + return PTR_ERR(acl); + + error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); + if (error) + return error; + + error = xfs_set_acl(inode, ACL_TYPE_ACCESS, acl); + posix_acl_release(acl); + return error; +} + +static int +xfs_xattr_acl_get(struct dentry *dentry, const char *name, + void *value, size_t size, int type) +{ + struct posix_acl *acl; + int error; + + acl = xfs_get_acl(dentry->d_inode, type); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl == NULL) + return -ENODATA; + + error = posix_acl_to_xattr(acl, value, size); + posix_acl_release(acl); + + return error; +} + +static int +xfs_xattr_acl_set(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags, int type) +{ + struct inode *inode = dentry->d_inode; + struct posix_acl *acl = NULL; + int error = 0; + + if (flags & XATTR_CREATE) + return -EINVAL; + if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) + return value ? -EACCES : 0; + if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER)) + return -EPERM; + + if (!value) + goto set_acl; + + acl = posix_acl_from_xattr(value, size); + if (!acl) { + /* + * acl_set_file(3) may request that we set default ACLs with + * zero length -- defend (gracefully) against that here. + */ + goto out; + } + if (IS_ERR(acl)) { + error = PTR_ERR(acl); + goto out; + } + + error = posix_acl_valid(acl); + if (error) + goto out_release; + + error = -EINVAL; + if (acl->a_count > XFS_ACL_MAX_ENTRIES) + goto out_release; + + if (type == ACL_TYPE_ACCESS) { + umode_t mode = inode->i_mode; + error = posix_acl_equiv_mode(acl, &mode); + + if (error <= 0) { + posix_acl_release(acl); + acl = NULL; + + if (error < 0) + return error; + } + + error = xfs_set_mode(inode, mode); + if (error) + goto out_release; + } + + set_acl: + error = xfs_set_acl(inode, type, acl); + out_release: + posix_acl_release(acl); + out: + return error; +} + +const struct xattr_handler xfs_xattr_acl_access_handler = { + .prefix = POSIX_ACL_XATTR_ACCESS, + .flags = ACL_TYPE_ACCESS, + .get = xfs_xattr_acl_get, + .set = xfs_xattr_acl_set, +}; + +const struct xattr_handler xfs_xattr_acl_default_handler = { + .prefix = POSIX_ACL_XATTR_DEFAULT, + .flags = ACL_TYPE_DEFAULT, + .get = xfs_xattr_acl_get, + .set = xfs_xattr_acl_set, +}; |