/* * mm/shmem_acl.c * * (C) 2005 Andreas Gruenbacher <agruen@suse.de> * * This file is released under the GPL. */ #include <linux/fs.h> #include <linux/shmem_fs.h> #include <linux/xattr.h> #include <linux/generic_acl.h> /** * shmem_get_acl - generic_acl_operations->getacl() operation */ static struct posix_acl * shmem_get_acl(struct inode *inode, int type) { struct posix_acl *acl = NULL; spin_lock(&inode->i_lock); switch(type) { case ACL_TYPE_ACCESS: acl = posix_acl_dup(SHMEM_I(inode)->i_acl); break; case ACL_TYPE_DEFAULT: acl = posix_acl_dup(SHMEM_I(inode)->i_default_acl); break; } spin_unlock(&inode->i_lock); return acl; } /** * shmem_set_acl - generic_acl_operations->setacl() operation */ static void shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl) { struct posix_acl *free = NULL; spin_lock(&inode->i_lock); switch(type) { case ACL_TYPE_ACCESS: free = SHMEM_I(inode)->i_acl; SHMEM_I(inode)->i_acl = posix_acl_dup(acl); break; case ACL_TYPE_DEFAULT: free = SHMEM_I(inode)->i_default_acl; SHMEM_I(inode)->i_default_acl = posix_acl_dup(acl); break; } spin_unlock(&inode->i_lock); posix_acl_release(free); } struct generic_acl_operations shmem_acl_ops = { .getacl = shmem_get_acl, .setacl = shmem_set_acl, }; /** * shmem_list_acl_access, shmem_get_acl_access, shmem_set_acl_access, * shmem_xattr_acl_access_handler - plumbing code to implement the * system.posix_acl_access xattr using the generic acl functions. */ static size_t shmem_list_acl_access(struct inode *inode, char *list, size_t list_size, const char *name, size_t name_len) { return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, list, list_size); } static int shmem_get_acl_access(struct inode *inode, const char *name, void *buffer, size_t size) { if (strcmp(name, "") != 0) return -EINVAL; return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, buffer, size); } static int shmem_set_acl_access(struct inode *inode, const char *name, const void *value, size_t size, int flags) { if (strcmp(name, "") != 0) return -EINVAL; return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, value, size); } struct xattr_handler shmem_xattr_acl_access_handler = { .prefix = POSIX_ACL_XATTR_ACCESS, .list = shmem_list_acl_access, .get = shmem_get_acl_access, .set = shmem_set_acl_access, }; /** * shmem_list_acl_default, shmem_get_acl_default, shmem_set_acl_default, * shmem_xattr_acl_default_handler - plumbing code to implement the * system.posix_acl_default xattr using the generic acl functions. */ static size_t shmem_list_acl_default(struct inode *inode, char *list, size_t list_size, const char *name, size_t name_len) { return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, list, list_size); } static int shmem_get_acl_default(struct inode *inode, const char *name, void *buffer, size_t size) { if (strcmp(name, "") != 0) return -EINVAL; return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, buffer, size); } static int shmem_set_acl_default(struct inode *inode, const char *name, const void *value, size_t size, int flags) { if (strcmp(name, "") != 0) return -EINVAL; return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, value, size); } struct xattr_handler shmem_xattr_acl_default_handler = { .prefix = POSIX_ACL_XATTR_DEFAULT, .list = shmem_list_acl_default, .get = shmem_get_acl_default, .set = shmem_set_acl_default, }; /** * shmem_acl_init - Inizialize the acl(s) of a new inode */ int shmem_acl_init(struct inode *inode, struct inode *dir) { return generic_acl_init(inode, dir, &shmem_acl_ops); } /** * shmem_acl_destroy_inode - destroy acls hanging off the in-memory inode * * This is done before destroying the actual inode. */ void shmem_acl_destroy_inode(struct inode *inode) { if (SHMEM_I(inode)->i_acl) posix_acl_release(SHMEM_I(inode)->i_acl); SHMEM_I(inode)->i_acl = NULL; if (SHMEM_I(inode)->i_default_acl) posix_acl_release(SHMEM_I(inode)->i_default_acl); SHMEM_I(inode)->i_default_acl = NULL; } /** * shmem_check_acl - check_acl() callback for generic_permission() */ static int shmem_check_acl(struct inode *inode, int mask) { struct posix_acl *acl = shmem_get_acl(inode, ACL_TYPE_ACCESS); if (acl) { int error = posix_acl_permission(inode, acl, mask); posix_acl_release(acl); return error; } return -EAGAIN; } /** * shmem_permission - permission() inode operation */ int shmem_permission(struct inode *inode, int mask, struct nameidata *nd) { return generic_permission(inode, mask, shmem_check_acl); }