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_ */
128