/*

   * linux/fs/9p/error.c

   *

   * Error string handling

   *

   * Plan 9 uses error strings, Unix uses error numbers.  These functions
   * try to help manage that and provide for dynamically adding error
   * mappings.

   *
   *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   *
   *  This program is free software; you can redistribute it and/or modify

   *  it under the terms of the GNU General Public License version 2
   *  as published by the Free Software Foundation.

   *
   *  This program is distributed in the hope that it will 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 to:
   *  Free Software Foundation
   *  51 Franklin Street, Fifth Floor
   *  Boston, MA  02111-1301  USA
   *
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  #include <linux/module.h>
  #include <linux/list.h>
  #include <linux/jhash.h>

  #include <linux/errno.h>

  #include <net/9p/9p.h>

  /**
   * struct errormap - map string errors from Plan 9 to Linux numeric ids
   * @name: string sent over 9P
   * @val: numeric id most closely representing @name
   * @namelen: length of string
   * @list: hash-table list for string lookup
   */

  struct errormap {
  	char *name;
  	int val;

  	int namelen;

  	struct hlist_node list;
  };
  
  #define ERRHASHSZ		32
  static struct hlist_head hash_errmap[ERRHASHSZ];
  
  /* FixMe - reduce to a reasonable size */
  static struct errormap errmap[] = {

  	{"Operation not permitted", EPERM},
  	{"wstat prohibited", EPERM},
  	{"No such file or directory", ENOENT},

  	{"directory entry not found", ENOENT},

  	{"file not found", ENOENT},
  	{"Interrupted system call", EINTR},
  	{"Input/output error", EIO},
  	{"No such device or address", ENXIO},
  	{"Argument list too long", E2BIG},
  	{"Bad file descriptor", EBADF},
  	{"Resource temporarily unavailable", EAGAIN},
  	{"Cannot allocate memory", ENOMEM},
  	{"Permission denied", EACCES},
  	{"Bad address", EFAULT},
  	{"Block device required", ENOTBLK},
  	{"Device or resource busy", EBUSY},
  	{"File exists", EEXIST},
  	{"Invalid cross-device link", EXDEV},
  	{"No such device", ENODEV},
  	{"Not a directory", ENOTDIR},
  	{"Is a directory", EISDIR},
  	{"Invalid argument", EINVAL},
  	{"Too many open files in system", ENFILE},
  	{"Too many open files", EMFILE},
  	{"Text file busy", ETXTBSY},
  	{"File too large", EFBIG},
  	{"No space left on device", ENOSPC},
  	{"Illegal seek", ESPIPE},
  	{"Read-only file system", EROFS},
  	{"Too many links", EMLINK},
  	{"Broken pipe", EPIPE},
  	{"Numerical argument out of domain", EDOM},
  	{"Numerical result out of range", ERANGE},
  	{"Resource deadlock avoided", EDEADLK},
  	{"File name too long", ENAMETOOLONG},
  	{"No locks available", ENOLCK},
  	{"Function not implemented", ENOSYS},
  	{"Directory not empty", ENOTEMPTY},
  	{"Too many levels of symbolic links", ELOOP},
  	{"No message of desired type", ENOMSG},
  	{"Identifier removed", EIDRM},
  	{"No data available", ENODATA},
  	{"Machine is not on the network", ENONET},
  	{"Package not installed", ENOPKG},
  	{"Object is remote", EREMOTE},
  	{"Link has been severed", ENOLINK},
  	{"Communication error on send", ECOMM},
  	{"Protocol error", EPROTO},
  	{"Bad message", EBADMSG},
  	{"File descriptor in bad state", EBADFD},
  	{"Streams pipe error", ESTRPIPE},
  	{"Too many users", EUSERS},
  	{"Socket operation on non-socket", ENOTSOCK},
  	{"Message too long", EMSGSIZE},
  	{"Protocol not available", ENOPROTOOPT},
  	{"Protocol not supported", EPROTONOSUPPORT},
  	{"Socket type not supported", ESOCKTNOSUPPORT},
  	{"Operation not supported", EOPNOTSUPP},
  	{"Protocol family not supported", EPFNOSUPPORT},
  	{"Network is down", ENETDOWN},
  	{"Network is unreachable", ENETUNREACH},
  	{"Network dropped connection on reset", ENETRESET},
  	{"Software caused connection abort", ECONNABORTED},
  	{"Connection reset by peer", ECONNRESET},
  	{"No buffer space available", ENOBUFS},
  	{"Transport endpoint is already connected", EISCONN},
  	{"Transport endpoint is not connected", ENOTCONN},
  	{"Cannot send after transport endpoint shutdown", ESHUTDOWN},
  	{"Connection timed out", ETIMEDOUT},
  	{"Connection refused", ECONNREFUSED},
  	{"Host is down", EHOSTDOWN},
  	{"No route to host", EHOSTUNREACH},
  	{"Operation already in progress", EALREADY},
  	{"Operation now in progress", EINPROGRESS},
  	{"Is a named type file", EISNAM},
  	{"Remote I/O error", EREMOTEIO},
  	{"Disk quota exceeded", EDQUOT},

  /* errors from fossil, vacfs, and u9fs */
  	{"fid unknown or out of range", EBADF},
  	{"permission denied", EACCES},
  	{"file does not exist", ENOENT},
  	{"authentication failed", ECONNREFUSED},
  	{"bad offset in directory read", ESPIPE},
  	{"bad use of fid", EBADF},
  	{"wstat can't convert between files and directories", EPERM},
  	{"directory is not empty", ENOTEMPTY},
  	{"file exists", EEXIST},
  	{"file already exists", EEXIST},
  	{"file or directory already exists", EEXIST},
  	{"fid already in use", EBADF},
  	{"file in use", ETXTBSY},
  	{"i/o error", EIO},
  	{"file already open for I/O", ETXTBSY},
  	{"illegal mode", EINVAL},
  	{"illegal name", ENAMETOOLONG},
  	{"not a directory", ENOTDIR},

  	{"not a member of proposed group", EPERM},

  	{"not owner", EACCES},
  	{"only owner can change group in wstat", EACCES},
  	{"read only file system", EROFS},
  	{"no access to special file", EPERM},
  	{"i/o count too large", EIO},
  	{"unknown group", EINVAL},
  	{"unknown user", EINVAL},
  	{"bogus wstat buffer", EPROTO},
  	{"exclusive use file already open", EAGAIN},
  	{"corrupted directory entry", EIO},
  	{"corrupted file entry", EIO},
  	{"corrupted block label", EIO},
  	{"corrupted meta data", EIO},
  	{"illegal offset", EINVAL},
  	{"illegal path element", ENOENT},
  	{"root of file system is corrupted", EIO},
  	{"corrupted super block", EIO},
  	{"protocol botch", EPROTO},
  	{"file system is full", ENOSPC},
  	{"file is in use", EAGAIN},
  	{"directory entry is not allocated", ENOENT},
  	{"file is read only", EROFS},
  	{"file has been removed", EIDRM},
  	{"only support truncation to zero length", EPERM},
  	{"cannot remove root", EPERM},
  	{"file too big", EFBIG},
  	{"venti i/o error", EIO},
  	/* these are not errors */
  	{"u9fs rhostsauth: no authentication required", 0},
  	{"u9fs authnone: no authentication required", 0},
  	{NULL, -1}
  };

  /**

   * p9_error_init - preload mappings into hash list

   *
   */
  
  int p9_error_init(void)
  {
  	struct errormap *c;
  	int bucket;
  
  	/* initialize hash table */
  	for (bucket = 0; bucket < ERRHASHSZ; bucket++)
  		INIT_HLIST_HEAD(&hash_errmap[bucket]);
  
  	/* load initial error map into hash table */
  	for (c = errmap; c->name != NULL; c++) {
  		c->namelen = strlen(c->name);
  		bucket = jhash(c->name, c->namelen, 0) % ERRHASHSZ;
  		INIT_HLIST_NODE(&c->list);
  		hlist_add_head(&c->list, &hash_errmap[bucket]);
  	}
  
  	return 1;
  }
  EXPORT_SYMBOL(p9_error_init);
  
  /**
   * errstr2errno - convert error string to error number
   * @errstr: error string

   * @len: length of error string

   *
   */
  
  int p9_errstr2errno(char *errstr, int len)
  {
  	int errno;

  	struct errormap *c;
  	int bucket;
  
  	errno = 0;

  	c = NULL;
  	bucket = jhash(errstr, len, 0) % ERRHASHSZ;

  	hlist_for_each_entry(c, &hash_errmap[bucket], list) {

  		if (c->namelen == len && !memcmp(c->name, errstr, len)) {
  			errno = c->val;
  			break;
  		}
  	}
  
  	if (errno == 0) {
  		/* TODO: if error isn't found, add it dynamically */
  		errstr[len] = 0;

  		pr_err("%s: server reported unknown error %s
  ",
  		       __func__, errstr);

  		errno = ESERVERFAULT;

  	}
  
  	return -errno;
  }
  EXPORT_SYMBOL(p9_errstr2errno);