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 */
  23 enum env_action {
  24         ENV_FIND,
  25         ENV_ENTER,
  26 };
  27
  28 /** struct env_entry - An entry in the environment hashtable */
  29 struct 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.  */
  46 struct 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.  */
  62 int hcreate_r(size_t nel, struct hsearch_data *htab);
  63
  64 /* Destroy current internal hash table.  */
  65 void 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  * */
  73 int 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  */
  80 int 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  */
  93 int hdelete_r(const char *key, struct hsearch_data *htab, int flag);
  94
  95 ssize_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  */
 102 int 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 */
 107 int 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_ */