1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
/**
* @file parser_schema.h
* @author Radek Krejci <rkrejci@cesnet.cz>
* @author Michal Vasko <mvasko@cesnet.cz>
* @brief Schema parsers for libyang
*
* Copyright (c) 2015 - 2026 CESNET, z.s.p.o.
*
* This source code is licensed under BSD 3-Clause License (the "License").
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://opensource.org/licenses/BSD-3-Clause
*/
#ifndef LY_PARSER_SCHEMA_H_
#define LY_PARSER_SCHEMA_H_
#include "log.h"
#ifdef __cplusplus
extern "C" {
#endif
struct ly_in;
struct lys_module;
/**
* @page howtoSchemaParsers Parsing YANG Modules
*
* YANG module parsers allow to read YANG module from a specific format. libyang supports the following module formats:
*
* - YANG
*
* Basic YANG schemas format described in [RFC 6020](http://tools.ietf.org/html/rfc6020) and
* [RFC 7951](http://tools.ietf.org/html/rfc7951) (so both YANG 1.0 and YANG 1.1 versions are supported).
*
* - YIN
*
* Alternative XML-based format to YANG - YANG Independent Notation. The details can be found in
* [RFC 6020](http://tools.ietf.org/html/rfc6020#section-11) and
* [RFC 7951](http://tools.ietf.org/html/rfc7951#section-13).
*
* When the [context](@ref howtoContext) is created, it already contains the following YANG modules, which
* are implemented internally by libyang:
* - ietf-inet-types@2025-12-22
* - ietf-yang-types@2025-12-22
* - ietf-yang-metadata@2016-08-05
* - yang@2025-01-29
* - default@2025-06-18
* - ietf-yang-schema-mount@2019-01-14
* - ietf-yang-structure-ext@2020-06-17
* - ietf-datastores@2018-02-14
* - ietf-yang-library@2019-01-04
*
* The `yang` module is the libyang's internal module to provide namespace and definitions of for various YANG
* attributes described in [RFC 7951](https://tools.ietf.org/html/rfc6243) (such as `insert` attribute for
* edit-config's data).
*
* Other modules can be added to the context manually with the functions listed below. Besides them,
* it is also possible to use ::ly_ctx_load_module() which tries to find the required module automatically - using
* ::ly_module_imp_clb or automatic search in working directory and in the context's search directories. For details, see
* [how the context works](@ref howtoContext).
*
* YANG modules are loaded in two steps. First, the input YANG/YIN data are parsed into \b lysp_* structures that reflect
* the structure of the input module and submodule(s). Mostly just syntax checks are done, no reference or type checking is
* performed in this step. If the module is supposed to be implemented, not just imported by another module, the second step
* is to compile it. The compiled tree may significantly differ from the source (parsed) tree structure. All the references
* are resolved, groupings are instantiated, types are resolved (and compiled by joining all the relevant restrictions
* when derived from another types) and many other syntactical checks are done.
*
* There is the main parsing function ::lys_parse() working with the libyang [input handler](@ref howtoInput). However,
* to simplify some of the use-cases, it is also possible to use other functions accepting input data from various sources.
*
* Functions List
* --------------
* - ::lys_parse()
* - ::lys_parse_mem()
* - ::lys_parse_fd()
* - ::lys_parse_path()
*
* - ::lys_search_localfile()
* - ::ly_ctx_set_module_imp_clb()
* - ::ly_ctx_load_module()
*/
/**
* @addtogroup schematree
* @{
*/
/**
* @brief Schema input formats accepted by libyang [parser functions](@ref howtoSchemaParsers).
*/
typedef enum {
LYS_IN_UNKNOWN = 0, /**< unknown format, used as return value in case of error */
LYS_IN_YANG = 1, /**< YANG schema input format */
LYS_IN_YIN = 3 /**< YIN schema input format */
} LYS_INFORMAT;
/**
* @brief Load a schema into the specified context.
*
* @param[in] ctx libyang context to use.
* @param[in] in Input handle to provide the dumped module in the specified format.
* @param[in] format Format of the schema to parse. Can be 0 to try to detect format from the input handler.
* @param[in] features Array of features to enable ended with NULL. If NULL, no features are enabled.
* @param[out] module Optional parsed module.
* @return LY_ERR value.
*/
LIBYANG_API_DECL LY_ERR lys_parse(struct ly_ctx *ctx, struct ly_in *in, LYS_INFORMAT format, const char **features,
struct lys_module **module);
/**
* @brief Load a schema into the specified context.
*
* This function is considered for a simple use, if you have a complex use-case,
* consider use of ::lys_parse() with a standalone input handler.
*
* @param[in] ctx libyang context to use.
* @param[in] data String containing the dumped module in the specified format.
* @param[in] format Format of the schema to parse.
* @param[out] module Optional parsed module.
* @return LY_ERR value.
*/
LIBYANG_API_DECL LY_ERR lys_parse_mem(struct ly_ctx *ctx, const char *data, LYS_INFORMAT format, struct lys_module **module);
/**
* @brief Read a schema from file descriptor into the specified context.
*
* @note Current implementation supports only reading data from standard (disk) file, not from sockets, pipes, etc.
*
* This function is considered for a simple use, if you have a complex use-case,
* consider use of ::lys_parse() with a standalone input handler.
*
* @param[in] ctx libyang context to use.
* @param[in] fd File descriptor of a regular file (e.g. sockets are not supported) containing the schema
* in the specified format.
* @param[in] format Format of the schema to parse.
* @param[out] module Optional parsed module.
* @return LY_ERR value.
*/
LIBYANG_API_DECL LY_ERR lys_parse_fd(struct ly_ctx *ctx, int fd, LYS_INFORMAT format, struct lys_module **module);
/**
* @brief Load a schema into the specified context from a file.
*
* This function is considered for a simple use, if you have a complex use-case,
* consider use of ::lys_parse() with a standalone input handler.
*
* @param[in] ctx libyang context to use.
* @param[in] path Path to the file with the module in the specified format.
* @param[in] format Format of the schema to parse.
* @param[out] module Optional parsed module.
* @return LY_ERR value.
*/
LIBYANG_API_DECL LY_ERR lys_parse_path(struct ly_ctx *ctx, const char *path, LYS_INFORMAT format, struct lys_module **module);
/**
* @brief Search for the schema file in the specified searchpaths.
*
* @param[in] searchpaths NULL-terminated array of paths to be searched (recursively). Current working
* directory is searched automatically (but non-recursively if not in the provided list). Caller can use
* result of the ::ly_ctx_get_searchdirs().
* @param[in] cwd Flag to implicitly search also in the current working directory (non-recursively).
* @param[in] name Name of the schema to find.
* @param[in] revision Revision of the schema to find. If NULL, the newest found schema filepath is returned.
* @param[out] localfile Mandatory output variable containing absolute path of the found schema. If no schema
* complying the provided restriction is found, NULL is set.
* @param[out] format Optional output variable containing expected format of the schema document according to the
* file suffix.
* @return LY_ERR value (LY_SUCCESS is returned even if the file is not found, then the *localfile is NULL).
*/
LIBYANG_API_DECL LY_ERR lys_search_localfile(const char * const *searchpaths, ly_bool cwd, const char *name, const char *revision,
char **localfile, LYS_INFORMAT *format);
/** @} schematree */
#ifdef __cplusplus
}
#endif
#endif /* LY_PARSER_SCHEMA_H_ */