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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 <stddef.h>
18 
19 #define __set_errno(val) do { errno = val; } while (0)
20 
21 enum env_op {
22 	env_op_create,
23 	env_op_delete,
24 	env_op_overwrite,
25 };
26 
27 /* Action which shall be performed in the call to hsearch.  */
28 typedef enum {
29 	FIND,
30 	ENTER
31 } ACTION;
32 
33 typedef struct entry {
34 	const char *key;
35 	char *data;
36 	int (*callback)(const char *name, const char *value, enum env_op op,
37 		int flags);
38 	int flags;
39 } ENTRY;
40 
41 /* Opaque type for internal use.  */
42 struct _ENTRY;
43 
44 /*
45  * Family of hash table handling functions.  The functions also
46  * have reentrant counterparts ending with _r.  The non-reentrant
47  * functions all work on a single internal hash table.
48  */
49 
50 /* Data type for reentrant functions.  */
51 struct hsearch_data {
52 	struct _ENTRY *table;
53 	unsigned int size;
54 	unsigned int filled;
55 /*
56  * Callback function which will check whether the given change for variable
57  * "__item" to "newval" may be applied or not, and possibly apply such change.
58  * When (flag & H_FORCE) is set, it shall not print out any error message and
59  * shall force overwriting of write-once variables.
60  * Must return 0 for approval, 1 for denial.
61  */
62 	int (*change_ok)(const ENTRY *__item, const char *newval, enum env_op,
63 		int flag);
64 };
65 
66 /* Create a new hash table which will contain at most "__nel" elements.  */
67 extern int hcreate_r(size_t __nel, struct hsearch_data *__htab);
68 
69 /* Destroy current internal hash table.  */
70 extern void hdestroy_r(struct hsearch_data *__htab);
71 
72 /*
73  * Search for entry matching __item.key in internal hash table.  If
74  * ACTION is `FIND' return found entry or signal error by returning
75  * NULL.  If ACTION is `ENTER' replace existing data (if any) with
76  * __item.data.
77  * */
78 extern int hsearch_r(ENTRY __item, ACTION __action, ENTRY ** __retval,
79 		     struct hsearch_data *__htab, int __flag);
80 
81 /*
82  * Search for an entry matching "__match".  Otherwise, Same semantics
83  * as hsearch_r().
84  */
85 extern int hmatch_r(const char *__match, int __last_idx, ENTRY ** __retval,
86 		    struct hsearch_data *__htab);
87 
88 /* Search and delete entry matching "__key" in internal hash table. */
89 extern int hdelete_r(const char *__key, struct hsearch_data *__htab,
90 		     int __flag);
91 
92 extern ssize_t hexport_r(struct hsearch_data *__htab,
93 		     const char __sep, int __flag, char **__resp, size_t __size,
94 		     int argc, char * const argv[]);
95 
96 /*
97  * nvars: length of vars array
98  * vars: array of strings (variable names) to import (nvars == 0 means all)
99  */
100 extern int himport_r(struct hsearch_data *__htab,
101 		     const char *__env, size_t __size, const char __sep,
102 		     int __flag, int __crlf_is_lf, int nvars,
103 		     char * const vars[]);
104 
105 /* Walk the whole table calling the callback on each element */
106 extern int hwalk_r(struct hsearch_data *__htab, int (*callback)(ENTRY *));
107 
108 /* Flags for himport_r(), hexport_r(), hdelete_r(), and hsearch_r() */
109 #define H_NOCLEAR	(1 << 0) /* do not clear hash table before importing */
110 #define H_FORCE		(1 << 1) /* overwrite read-only/write-once variables */
111 #define H_INTERACTIVE	(1 << 2) /* indicate that an import is user directed */
112 #define H_HIDE_DOT	(1 << 3) /* don't print env vars that begin with '.' */
113 #define H_MATCH_KEY	(1 << 4) /* search/grep key  = variable names	     */
114 #define H_MATCH_DATA	(1 << 5) /* search/grep data = variable values	     */
115 #define H_MATCH_BOTH	(H_MATCH_KEY | H_MATCH_DATA) /* search/grep both     */
116 #define H_MATCH_IDENT	(1 << 6) /* search for indentical strings	     */
117 #define H_MATCH_SUBSTR	(1 << 7) /* search for substring matches	     */
118 #define H_MATCH_REGEX	(1 << 8) /* search for regular expression matches    */
119 #define H_MATCH_METHOD	(H_MATCH_IDENT | H_MATCH_SUBSTR | H_MATCH_REGEX)
120 #define H_PROGRAMMATIC	(1 << 9) /* indicate that an import is from env_set() */
121 #define H_ORIGIN_FLAGS	(H_INTERACTIVE | H_PROGRAMMATIC)
122 
123 #endif /* _SEARCH_H_ */
124