LXR uboot/include/search.h

   1/* SPDX-License-Identifier: LGPL-2.1+ */
   2/*
   3 * Declarations for System V style searching functions.
   4 * Copyright (C) 1995-1999, 2000 Free Software Foundation, Inc.
   5 * This file is part of the GNU C Library.
   6 */
   7
   8/*
   9 * Based on code from uClibc-0.9.30.3
  10 * Extensions for use within U-Boot
  11 * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
  12 */
  13
  14#ifndef _SEARCH_H_
  15#define _SEARCH_H_
  16
  17#include <env.h>
  18#include <stddef.h>
  19
  20#define set_errno(val) do { errno = val; } while (0)
  21
  22/* enum env_action: action which shall be performed in the call to hsearch */
  23enum env_action {
  24        ENV_FIND,
  25        ENV_ENTER,
  26};
  27
  28/** struct env_entry - An entry in the environment hashtable */
  29struct env_entry {
  30        const char *key;
  31        char *data;
  32#ifndef CONFIG_SPL_BUILD
  33        int (*callback)(const char *name, const char *value, enum env_op op,
  34                int flags);
  35#endif
  36        int flags;
  37};
  38
  39/*
  40 * Family of hash table handling functions.  The functions also
  41 * have reentrant counterparts ending with _r.  The non-reentrant
  42 * functions all work on a single internal hash table.
  43 */
  44
  45/* Data type for reentrant functions.  */
  46struct hsearch_data {
  47        struct env_entry_node *table;
  48        unsigned int size;
  49        unsigned int filled;
  50/*
  51 * Callback function which will check whether the given change for variable
  52 * "item" to "newval" may be applied or not, and possibly apply such change.
  53 * When (flag & H_FORCE) is set, it shall not print out any error message and
  54 * shall force overwriting of write-once variables.
  55 * Must return 0 for approval, 1 for denial.
  56 */
  57        int (*change_ok)(const struct env_entry *item, const char *newval,
  58                         enum env_op, int flag);
  59};
  60
  61/* Create a new hash table which will contain at most "nel" elements.  */
  62int hcreate_r(size_t nel, struct hsearch_data *htab);
  63
  64/* Destroy current internal hash table.  */
  65void hdestroy_r(struct hsearch_data *htab);
  66
  67/*
  68 * Search for entry matching item.key in internal hash table.  If
  69 * action is `ENV_FIND' return found entry or signal error by returning
  70 * NULL.  If action is `ENV_ENTER' replace existing data (if any) with
  71 * item.data.
  72 * */
  73int hsearch_r(struct env_entry item, enum env_action action,
  74              struct env_entry **retval, struct hsearch_data *htab, int flag);
  75
  76/*
  77 * Search for an entry matching "match".  Otherwise, Same semantics
  78 * as hsearch_r().
  79 */
  80int hmatch_r(const char *match, int last_idx, struct env_entry **retval,
  81             struct hsearch_data *htab);
  82
  83/**
  84 * hdelete_r() - Search and delete entry in internal hash table
  85 *
  86 * @key: Name of entry to delete
  87 * @htab: Hash table
  88 * @flag: Flags to use (H_...)
  89 * @return 0 on success, -ENOENT if not found, -EPERM if the hash table callback
  90 *      rejected changing the variable, -EINVAL if the hash table refused to
  91 *      delete the variable
  92 */
  93int hdelete_r(const char *key, struct hsearch_data *htab, int flag);
  94
  95ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,
  96                  char **resp, size_t size, int argc, char *const argv[]);
  97
  98/*
  99 * nvars: length of vars array
 100 * vars: array of strings (variable names) to import (nvars == 0 means all)
 101 */
 102int himport_r(struct hsearch_data *htab, const char *env, size_t size,
 103              const char sep, int flag, int crlf_is_lf, int nvars,
 104              char * const vars[]);
 105
 106/* Walk the whole table calling the callback on each element */
 107int hwalk_r(struct hsearch_data *htab,
 108            int (*callback)(struct env_entry *entry));
 109
 110/* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
 111#define H_NOCLEAR       (1 << 0) /* do not clear hash table before importing */
 112#define H_FORCE         (1 << 1) /* overwrite read-only/write-once variables */
 113#define H_INTERACTIVE   (1 << 2) /* indicate that an import is user directed */
 114#define H_HIDE_DOT      (1 << 3) /* don't print env vars that begin with '.' */
 115#define H_MATCH_KEY     (1 << 4) /* search/grep key  = variable names        */
 116#define H_MATCH_DATA    (1 << 5) /* search/grep data = variable values       */
 117#define H_MATCH_BOTH    (H_MATCH_KEY | H_MATCH_DATA) /* search/grep both     */
 118#define H_MATCH_IDENT   (1 << 6) /* search for indentical strings            */
 119#define H_MATCH_SUBSTR  (1 << 7) /* search for substring matches             */
 120#define H_MATCH_REGEX   (1 << 8) /* search for regular expression matches    */
 121#define H_MATCH_METHOD  (H_MATCH_IDENT | H_MATCH_SUBSTR | H_MATCH_REGEX)
 122#define H_PROGRAMMATIC  (1 << 9) /* indicate that an import is from env_set() */
 123#define H_ORIGIN_FLAGS  (H_INTERACTIVE | H_PROGRAMMATIC)
 124#define H_DEFAULT       (1 << 10) /* indicate that an import is default env */
 125#define H_EXTERNAL      (1 << 11) /* indicate that an import is external env */
 126
 127#endif /* _SEARCH_H_ */
 128