// SPDX-License-Identifier: GPL-2.0

  /*
   * (C) 2001 Clemson University and The University of Chicago
   *
   * See COPYING in top-level directory.
   */
  
  /*
   *  Linux VFS extended attribute operations.
   */
  
  #include "protocol.h"

  #include "orangefs-kernel.h"
  #include "orangefs-bufmap.h"

  #include <linux/posix_acl_xattr.h>
  #include <linux/xattr.h>

  #define SYSTEM_ORANGEFS_KEY "system.pvfs2."
  #define SYSTEM_ORANGEFS_KEY_LEN 13

  
  /*
   * this function returns
   *   0 if the key corresponding to name is not meant to be printed as part
   *     of a listxattr.
   *   1 if the key corresponding to name is meant to be returned as part of
   *     a listxattr.

   * The ones that start SYSTEM_ORANGEFS_KEY are the ones to avoid printing.

   */
  static int is_reserved_key(const char *key, size_t size)
  {

  	if (size < SYSTEM_ORANGEFS_KEY_LEN)

  		return 1;

  	return strncmp(key, SYSTEM_ORANGEFS_KEY, SYSTEM_ORANGEFS_KEY_LEN) ?  1 : 0;

  }
  
  static inline int convert_to_internal_xattr_flags(int setxattr_flags)
  {
  	int internal_flag = 0;
  
  	if (setxattr_flags & XATTR_REPLACE) {
  		/* Attribute must exist! */

  		internal_flag = ORANGEFS_XATTR_REPLACE;

  	} else if (setxattr_flags & XATTR_CREATE) {
  		/* Attribute must not exist */

  		internal_flag = ORANGEFS_XATTR_CREATE;

  	}
  	return internal_flag;
  }
  
  
  /*
   * Tries to get a specified key's attributes of a given
   * file into a user-specified buffer. Note that the getxattr
   * interface allows for the users to probe the size of an
   * extended attribute by passing in a value of 0 to size.
   * Thus our return value is always the size of the attribute
   * unless the key does not exist for the file and/or if
   * there were errors in fetching the attribute value.
   */

  ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
  				void *buffer, size_t size)

  {

  	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
  	struct orangefs_kernel_op_s *new_op = NULL;

  	ssize_t ret = -ENOMEM;
  	ssize_t length = 0;
  	int fsuid;
  	int fsgid;
  
  	gossip_debug(GOSSIP_XATTR_DEBUG,

  		     "%s: name %s, buffer_size %zd
  ",
  		     __func__, name, size);

  	if (S_ISLNK(inode->i_mode))
  		return -EOPNOTSUPP;

  	if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)

  		return -EINVAL;

  	fsuid = from_kuid(&init_user_ns, current_fsuid());
  	fsgid = from_kgid(&init_user_ns, current_fsgid());

  
  	gossip_debug(GOSSIP_XATTR_DEBUG,
  		     "getxattr on inode %pU, name %s "
  		     "(uid %o, gid %o)
  ",
  		     get_khandle_from_ino(inode),
  		     name,
  		     fsuid,
  		     fsgid);

  	down_read(&orangefs_inode->xattr_sem);

  	new_op = op_alloc(ORANGEFS_VFS_OP_GETXATTR);

  	if (!new_op)
  		goto out_unlock;

  	new_op->upcall.req.getxattr.refn = orangefs_inode->refn;

  	strcpy(new_op->upcall.req.getxattr.key, name);

  
  	/*
  	 * NOTE: Although keys are meant to be NULL terminated textual
  	 * strings, I am going to explicitly pass the length just in case
  	 * we change this later on...
  	 */

  	new_op->upcall.req.getxattr.key_sz = strlen(name) + 1;

  	ret = service_operation(new_op, "orangefs_inode_getxattr",

  				get_interruptible_flag(inode));
  	if (ret != 0) {
  		if (ret == -ENOENT) {
  			ret = -ENODATA;
  			gossip_debug(GOSSIP_XATTR_DEBUG,

  				     "orangefs_inode_getxattr: inode %pU key %s"

  				     " does not exist!
  ",
  				     get_khandle_from_ino(inode),
  				     (char *)new_op->upcall.req.getxattr.key);
  		}
  		goto out_release_op;
  	}
  
  	/*
  	 * Length returned includes null terminator.
  	 */
  	length = new_op->downcall.resp.getxattr.val_sz;
  
  	/*
  	 * Just return the length of the queried attribute.
  	 */
  	if (size == 0) {
  		ret = length;
  		goto out_release_op;
  	}
  
  	/*
  	 * Check to see if key length is > provided buffer size.
  	 */
  	if (length > size) {
  		ret = -ERANGE;
  		goto out_release_op;
  	}

  	memcpy(buffer, new_op->downcall.resp.getxattr.val, length);

  	memset(buffer + length, 0, size - length);

  	gossip_debug(GOSSIP_XATTR_DEBUG,

  	     "orangefs_inode_getxattr: inode %pU "

  	     "key %s key_sz %d, val_len %d
  ",
  	     get_khandle_from_ino(inode),
  	     (char *)new_op->
  		upcall.req.getxattr.key,
  		     (int)new_op->
  		upcall.req.getxattr.key_sz,
  	     (int)ret);
  
  	ret = length;
  
  out_release_op:
  	op_release(new_op);
  out_unlock:

  	up_read(&orangefs_inode->xattr_sem);

  	return ret;
  }

  static int orangefs_inode_removexattr(struct inode *inode, const char *name,
  				      int flags)

  {

  	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
  	struct orangefs_kernel_op_s *new_op = NULL;

  	int ret = -ENOMEM;

  	if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)

  		return -EINVAL;

  	down_write(&orangefs_inode->xattr_sem);
  	new_op = op_alloc(ORANGEFS_VFS_OP_REMOVEXATTR);

  	if (!new_op)
  		goto out_unlock;

  	new_op->upcall.req.removexattr.refn = orangefs_inode->refn;

  	/*
  	 * NOTE: Although keys are meant to be NULL terminated
  	 * textual strings, I am going to explicitly pass the
  	 * length just in case we change this later on...
  	 */

  	strcpy(new_op->upcall.req.removexattr.key, name);
  	new_op->upcall.req.removexattr.key_sz = strlen(name) + 1;

  
  	gossip_debug(GOSSIP_XATTR_DEBUG,

  		     "orangefs_inode_removexattr: key %s, key_sz %d
  ",

  		     (char *)new_op->upcall.req.removexattr.key,
  		     (int)new_op->upcall.req.removexattr.key_sz);
  
  	ret = service_operation(new_op,

  				"orangefs_inode_removexattr",

  				get_interruptible_flag(inode));
  	if (ret == -ENOENT) {
  		/*
  		 * Request to replace a non-existent attribute is an error.
  		 */
  		if (flags & XATTR_REPLACE)
  			ret = -ENODATA;
  		else
  			ret = 0;
  	}
  
  	gossip_debug(GOSSIP_XATTR_DEBUG,

  		     "orangefs_inode_removexattr: returning %d
  ", ret);

  
  	op_release(new_op);
  out_unlock:

  	up_write(&orangefs_inode->xattr_sem);

  	return ret;
  }
  
  /*
   * Tries to set an attribute for a given key on a file.
   *
   * Returns a -ve number on error and 0 on success.  Key is text, but value
   * can be binary!
   */

  int orangefs_inode_setxattr(struct inode *inode, const char *name,
  			    const void *value, size_t size, int flags)

  {

  	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
  	struct orangefs_kernel_op_s *new_op;

  	int internal_flag = 0;
  	int ret = -ENOMEM;
  
  	gossip_debug(GOSSIP_XATTR_DEBUG,

  		     "%s: name %s, buffer_size %zd
  ",
  		     __func__, name, size);

  	if (size > ORANGEFS_MAX_XATTR_VALUELEN)
  		return -EINVAL;

  	if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)

  		return -EINVAL;

  	internal_flag = convert_to_internal_xattr_flags(flags);

  	/* This is equivalent to a removexattr */

  	if (size == 0 && !value) {

  		gossip_debug(GOSSIP_XATTR_DEBUG,

  			     "removing xattr (%s)
  ",

  			     name);

  		return orangefs_inode_removexattr(inode, name, flags);

  	}
  
  	gossip_debug(GOSSIP_XATTR_DEBUG,
  		     "setxattr on inode %pU, name %s
  ",
  		     get_khandle_from_ino(inode),
  		     name);

  	down_write(&orangefs_inode->xattr_sem);
  	new_op = op_alloc(ORANGEFS_VFS_OP_SETXATTR);

  	if (!new_op)
  		goto out_unlock;

  	new_op->upcall.req.setxattr.refn = orangefs_inode->refn;

  	new_op->upcall.req.setxattr.flags = internal_flag;
  	/*
  	 * NOTE: Although keys are meant to be NULL terminated textual
  	 * strings, I am going to explicitly pass the length just in
  	 * case we change this later on...
  	 */

  	strcpy(new_op->upcall.req.setxattr.keyval.key, name);
  	new_op->upcall.req.setxattr.keyval.key_sz = strlen(name) + 1;

  	memcpy(new_op->upcall.req.setxattr.keyval.val, value, size);
  	new_op->upcall.req.setxattr.keyval.val_sz = size;
  
  	gossip_debug(GOSSIP_XATTR_DEBUG,

  		     "orangefs_inode_setxattr: key %s, key_sz %d "

  		     " value size %zd
  ",
  		     (char *)new_op->upcall.req.setxattr.keyval.key,
  		     (int)new_op->upcall.req.setxattr.keyval.key_sz,
  		     size);
  
  	ret = service_operation(new_op,

  				"orangefs_inode_setxattr",

  				get_interruptible_flag(inode));
  
  	gossip_debug(GOSSIP_XATTR_DEBUG,

  		     "orangefs_inode_setxattr: returning %d
  ",

  		     ret);
  
  	/* when request is serviced properly, free req op struct */
  	op_release(new_op);
  out_unlock:

  	up_write(&orangefs_inode->xattr_sem);

  	return ret;
  }
  
  /*
   * Tries to get a specified object's keys into a user-specified buffer of a
   * given size.  Note that like the previous instances of xattr routines, this
   * also allows you to pass in a NULL pointer and 0 size to probe the size for
   * subsequent memory allocations. Thus our return value is always the size of
   * all the keys unless there were errors in fetching the keys!
   */

  ssize_t orangefs_listxattr(struct dentry *dentry, char *buffer, size_t size)

  {
  	struct inode *inode = dentry->d_inode;

  	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
  	struct orangefs_kernel_op_s *new_op;
  	__u64 token = ORANGEFS_ITERATE_START;

  	ssize_t ret = -ENOMEM;
  	ssize_t total = 0;

  	int count_keys = 0;
  	int key_size;
  	int i = 0;

  	int returned_count = 0;

  	if (size > 0 && !buffer) {

  		gossip_err("%s: bogus NULL pointers
  ", __func__);
  		return -EINVAL;
  	}

  	down_read(&orangefs_inode->xattr_sem);
  	new_op = op_alloc(ORANGEFS_VFS_OP_LISTXATTR);

  	if (!new_op)
  		goto out_unlock;
  
  	if (buffer && size > 0)
  		memset(buffer, 0, size);
  
  try_again:
  	key_size = 0;

  	new_op->upcall.req.listxattr.refn = orangefs_inode->refn;

  	new_op->upcall.req.listxattr.token = token;
  	new_op->upcall.req.listxattr.requested_count =

  	    (size == 0) ? 0 : ORANGEFS_MAX_XATTR_LISTLEN;

  	ret = service_operation(new_op, __func__,
  				get_interruptible_flag(inode));
  	if (ret != 0)
  		goto done;
  
  	if (size == 0) {
  		/*
  		 * This is a bit of a big upper limit, but I did not want to
  		 * spend too much time getting this correct, since users end
  		 * up allocating memory rather than us...
  		 */
  		total = new_op->downcall.resp.listxattr.returned_count *

  			ORANGEFS_MAX_XATTR_NAMELEN;

  		goto done;
  	}

  	returned_count = new_op->downcall.resp.listxattr.returned_count;
  	if (returned_count < 0 ||

  	    returned_count > ORANGEFS_MAX_XATTR_LISTLEN) {

  		gossip_err("%s: impossible value for returned_count:%d:
  ",
  		__func__,
  		returned_count);

  		ret = -EIO;

  		goto done;
  	}

  	/*
  	 * Check to see how much can be fit in the buffer. Fit only whole keys.
  	 */

  	for (i = 0; i < returned_count; i++) {

  		if (new_op->downcall.resp.listxattr.lengths[i] < 0 ||
  		    new_op->downcall.resp.listxattr.lengths[i] >
  		    ORANGEFS_MAX_XATTR_NAMELEN) {
  			gossip_err("%s: impossible value for lengths[%d]
  ",
  			    __func__,
  			    new_op->downcall.resp.listxattr.lengths[i]);
  			ret = -EIO;
  			goto done;
  		}

  		if (total + new_op->downcall.resp.listxattr.lengths[i] > size)
  			goto done;
  
  		/*
  		 * Since many dumb programs try to setxattr() on our reserved
  		 * xattrs this is a feeble attempt at defeating those by not
  		 * listing them in the output of listxattr.. sigh
  		 */
  		if (is_reserved_key(new_op->downcall.resp.listxattr.key +
  				    key_size,
  				    new_op->downcall.resp.
  					listxattr.lengths[i])) {
  			gossip_debug(GOSSIP_XATTR_DEBUG, "Copying key %d -> %s
  ",
  					i, new_op->downcall.resp.listxattr.key +
  						key_size);
  			memcpy(buffer + total,
  				new_op->downcall.resp.listxattr.key + key_size,
  				new_op->downcall.resp.listxattr.lengths[i]);
  			total += new_op->downcall.resp.listxattr.lengths[i];
  			count_keys++;
  		} else {
  			gossip_debug(GOSSIP_XATTR_DEBUG, "[RESERVED] key %d -> %s
  ",
  					i, new_op->downcall.resp.listxattr.key +
  						key_size);
  		}
  		key_size += new_op->downcall.resp.listxattr.lengths[i];
  	}
  
  	/*
  	 * Since the buffer was large enough, we might have to continue
  	 * fetching more keys!
  	 */
  	token = new_op->downcall.resp.listxattr.token;

  	if (token != ORANGEFS_ITERATE_END)

  		goto try_again;
  
  done:
  	gossip_debug(GOSSIP_XATTR_DEBUG, "%s: returning %d"
  		     " [size of buffer %ld] (filled in %d keys)
  ",
  		     __func__,
  		     ret ? (int)ret : (int)total,
  		     (long)size,
  		     count_keys);
  	op_release(new_op);
  	if (ret == 0)
  		ret = total;
  out_unlock:

  	up_read(&orangefs_inode->xattr_sem);

  	return ret;
  }

  static int orangefs_xattr_set_default(const struct xattr_handler *handler,

  				      struct dentry *unused,
  				      struct inode *inode,

  				      const char *name,
  				      const void *buffer,
  				      size_t size,
  				      int flags)

  {

  	return orangefs_inode_setxattr(inode, name, buffer, size, flags);

  }

  static int orangefs_xattr_get_default(const struct xattr_handler *handler,

  				      struct dentry *unused,
  				      struct inode *inode,

  				      const char *name,
  				      void *buffer,
  				      size_t size)

  {

  	return orangefs_inode_getxattr(inode, name, buffer, size);

  
  }

  static const struct xattr_handler orangefs_xattr_default_handler = {

  	.prefix = "",  /* match any name => handlers called with full name */

  	.get = orangefs_xattr_get_default,
  	.set = orangefs_xattr_set_default,

  };

  const struct xattr_handler *orangefs_xattr_handlers[] = {

  	&posix_acl_access_xattr_handler,
  	&posix_acl_default_xattr_handler,

  	&orangefs_xattr_default_handler,

  	NULL
  };