src/context.c - github/CESNET/libyang - Gitiles

 /**
  * @file context.c
  * @author Radek Krejci <rkrejci@cesnet.cz>
  * @brief context implementation for libyang
  *
  * Copyright (c) 2015 CESNET, z.s.p.o.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  * 3. Neither the name of the Company nor the names of its contributors
  *    may be used to endorse or promote products derived from this
  *    software without specific prior written permission.
  */

 #define _GNU_SOURCE
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #include <errno.h>
 #include <fcntl.h>

 #include "common.h"
 #include "context.h"
 #include "dict_private.h"
 #include "parser.h"
 #include "tree_internal.h"

 #define IETF_INET_TYPES_PATH "../models/ietf-inet-types@2013-07-15.h"
 #define IETF_YANG_TYPES_PATH "../models/ietf-yang-types@2013-07-15.h"
 #define IETF_YANG_LIB_PATH "../models/ietf-yang-library@2015-07-03.h"

 #include IETF_INET_TYPES_PATH
 #include IETF_YANG_TYPES_PATH
 #include IETF_YANG_LIB_PATH

 API struct ly_ctx *
 ly_ctx_new(const char *search_dir)
 {
     struct ly_ctx *ctx;
     char *cwd;

     ctx = calloc(1, sizeof *ctx);
     if (!ctx) {
         LOGMEM;
         return NULL;
     }

     /* dictionary */
     lydict_init(&ctx->dict);

     /* models list */
     ctx->models.list = calloc(16, sizeof *ctx->models.list);
     if (!ctx->models.list) {
         LOGMEM;
         free(ctx);
         return NULL;
     }
     ctx->models.used = 0;
     ctx->models.size = 16;
     if (search_dir) {
         cwd = get_current_dir_name();
         if (chdir(search_dir)) {
             LOGERR(LY_ESYS, "Unable to use search directory \"%s\" (%s)",
                    search_dir, strerror(errno));
             free(cwd);
             ly_ctx_destroy(ctx);
             return NULL;
         }
         ctx->models.search_path = get_current_dir_name();
         chdir(cwd);
         free(cwd);
     }
     ctx->models.module_set_id = 1;

     /* load ietf-inet-types */
     ctx->models.list[0] = (struct lys_module *)lys_parse_data(ctx, (char *)ietf_inet_types_2013_07_15_yin, LYS_IN_YIN);
     if (!ctx->models.list[0]) {
         ly_ctx_destroy(ctx);
         return NULL;
     }

     /* load ietf-yang-types */
     ctx->models.list[1] = (struct lys_module *)lys_parse_data(ctx, (char *)ietf_yang_types_2013_07_15_yin, LYS_IN_YIN);
     if (!ctx->models.list[1]) {
         ly_ctx_destroy(ctx);
         return NULL;
     }

     /* load ietf-yang-library */
     ctx->models.list[2] = (struct lys_module *)lys_parse_data(ctx, (char *)ietf_yang_library_2015_07_03_yin, LYS_IN_YIN);
     if (!ctx->models.list[2]) {
         ly_ctx_destroy(ctx);
         return NULL;
     }

     return ctx;
 }

 API void
 ly_ctx_set_searchdir(struct ly_ctx *ctx, const char *search_dir)
 {
     char *cwd;

     if (!ctx) {
         return;
     }

     if (search_dir) {
         cwd = get_current_dir_name();
         if (chdir(search_dir)) {
             LOGERR(LY_ESYS, "Unable to use search directory \"%s\" (%s)",
                    search_dir, strerror(errno));
             free(cwd);
             return;
         }
         free(ctx->models.search_path);
         ctx->models.search_path = get_current_dir_name();

         chdir(cwd);
         free(cwd);
     } else {
         free(ctx->models.search_path);
         ctx->models.search_path = NULL;
     }
 }

 API const char *
 ly_ctx_get_searchdir(const struct ly_ctx *ctx)
 {
     return ctx->models.search_path;
 }

 API void
 ly_ctx_destroy(struct ly_ctx *ctx)
 {
     if (!ctx) {
         return;
     }

     /* models list */
     while (ctx->models.used) {
         lys_free(ctx->models.list[0], 1);
     }
     free(ctx->models.search_path);
     free(ctx->models.list);

     /* dictionary */
     lydict_clean(&ctx->dict);

     free(ctx);
 }

 API const struct lys_submodule *
 ly_ctx_get_submodule(const struct lys_module *module, const char *name, const char *revision)
 {
     struct lys_submodule *result;
     int i;

     if (!module || !name) {
         ly_errno = LY_EINVAL;
         return NULL;
     }

     /* TODO search also for submodules not directly available from the main module */

     /* search in modules included by the main module */
     if (module->type) {
         module = ((struct lys_submodule *)module)->belongsto;
     }
     for (i = 0; i < module->inc_size; i++) {
         result = module->inc[i].submodule;
         if (strcmp(name, result->name)) {
             continue;
         }

         if (!revision || (result->rev_size && !strcmp(revision, result->rev[0].date))) {
             return result;
         }
     }

     return NULL;
 }

 static const struct lys_module *
 ly_ctx_get_module_by(const struct ly_ctx *ctx, const char *key, int offset, const char *revision)
 {
     int i;
     struct lys_module *result = NULL;

     if (!ctx || !key) {
         ly_errno = LY_EINVAL;
         return NULL;
     }

     for (i = 0; i < ctx->models.used; i++) {
         /* use offset to get address of the pointer to string (char**), remember that offset is in
          * bytes, so we have to cast the pointer to the module to (char*), finally, we want to have
          * string not the pointer to string
          */
         if (!ctx->models.list[i] || strcmp(key, *(char**)(((char*)ctx->models.list[i]) + offset))) {
             continue;
         }

         if (!revision) {
             /* compare revisons and remember the newest one */
             if (result) {
                 if (!ctx->models.list[i]->rev_size) {
                     /* the current have no revision, keep the previous with some revision */
                     continue;
                 }
                 if (result->rev_size && strcmp(ctx->models.list[i]->rev[0].date, result->rev[0].date) < 0) {
                     /* the previous found matching module has a newer revision */
                     continue;
                 }
             }

             /* remember the current match and search for newer version */
             result = ctx->models.list[i];
         } else {
             if (ctx->models.list[i]->rev_size && !strcmp(revision, ctx->models.list[i]->rev[0].date)) {
                 /* matching revision */
                 result = ctx->models.list[i];
                 break;
             }
         }
     }

     return result;

 }

 API const struct lys_module *
 ly_ctx_get_module_by_ns(const struct ly_ctx *ctx, const char *ns, const char *revision)
 {
     return ly_ctx_get_module_by(ctx, ns, offsetof(struct lys_module, ns), revision);
 }

 API const struct lys_module *
 ly_ctx_get_module(const struct ly_ctx *ctx, const char *name, const char *revision)
 {
     return ly_ctx_get_module_by(ctx, name, offsetof(struct lys_module, name), revision);
 }

 API void
 ly_ctx_set_module_clb(struct ly_ctx *ctx, ly_module_clb clb, void *user_data)
 {
     ctx->module_clb = clb;
     ctx->module_clb_data = user_data;
 }

 API ly_module_clb
 ly_ctx_get_module_clb(const struct ly_ctx *ctx, void **user_data)
 {
     if (user_data) {
         *user_data = ctx->module_clb_data;
     }
     return ctx->module_clb;
 }

 API const struct lys_module *
 ly_ctx_load_module(struct ly_ctx *ctx, const char *name, const char *revision)
 {
     const struct lys_module *module;
     char *module_data;
     void (*module_data_free)(char *module_data) = NULL;
     LYS_INFORMAT format = LYS_IN_UNKNOWN;

     if (!ctx || !name) {
         ly_errno = LY_EINVAL;
         return NULL;
     }

     if (ctx->module_clb) {
         module_data = ctx->module_clb(name, revision, ctx->module_clb_data, &format, &module_data_free);
         if (!module_data) {
             LOGERR(LY_EVALID, "User module retrieval callback failed!");
             return NULL;
         }
         module = lys_parse_data(ctx, module_data, format);
         if (module_data_free) {
             module_data_free(module_data);
         } else {
             free(module_data);
         }
     } else {
         module = lyp_search_file(ctx, NULL, name, revision);
     }

     return module;
 }

 API const char **
 ly_ctx_get_module_names(const struct ly_ctx *ctx)
 {
     int i;
     const char **result = NULL;

     if (!ctx) {
         ly_errno = LY_EINVAL;
         return NULL;
     }

     result = malloc((ctx->models.used+1) * sizeof *result);
     if (!result) {
         LOGMEM;
         return NULL;
     }

     for (i = 0; i < ctx->models.used; i++) {
         result[i] = ctx->models.list[i]->name;
     }
     result[i] = NULL;

     return result;
 }

 API const char **
 ly_ctx_get_submodule_names(const struct ly_ctx *ctx, const char *module_name)
 {
     int i;
     const char **result = NULL;
     const struct lys_module *mod;

     if (!ctx) {
         ly_errno = LY_EINVAL;
         return NULL;
     }

     mod = ly_ctx_get_module(ctx, module_name, NULL);
     if (!mod) {
         LOGERR(LY_EVALID, "Data model \"%s\" not loaded", module_name);
         return NULL;
     }

     result = malloc((mod->inc_size+1) * sizeof *result);
     if (!result) {
         LOGMEM;
         return NULL;
     }

     for (i = 0; i < mod->inc_size; i++) {
         result[i] = mod->inc[i].submodule->name;
     }
     result[i] = NULL;

     return result;
 }

 static int
 ylib_feature(struct lyd_node *parent, struct lys_module *cur_mod)
 {
     int i, j;

     /* module features */
     for (i = 0; i < cur_mod->features_size; ++i) {
         if (!(cur_mod->features[i].flags & LYS_FENABLED)) {
             continue;
         }

         if (!lyd_new_leaf(parent, NULL, "feature", cur_mod->features[i].name)) {
             return EXIT_FAILURE;
         }
     }

     /* submodule features */
     for (i = 0; i < cur_mod->inc_size; ++i) {
         for (j = 0; j < cur_mod->inc[i].submodule->features_size; ++j) {
             if (!(cur_mod->inc[i].submodule->features[j].flags & LYS_FENABLED)) {
                 continue;
             }

             if (!lyd_new_leaf(parent, NULL, "feature", cur_mod->inc[i].submodule->features[j].name)) {
                 return EXIT_FAILURE;
             }
         }
     }

     return EXIT_SUCCESS;
 }

 static int
 ylib_deviation(struct lyd_node *parent, struct lys_module *cur_mod, struct ly_ctx *ctx)
 {
     int i, j, k;
     struct lys_module *target_module, *mod_iter;
     struct lyd_node *cont;

     for (i = 0; i < ctx->models.used; ++i) {
         mod_iter = ctx->models.list[i];
         for (k = 0; k < mod_iter->deviation_size; ++k) {
             if (mod_iter->deviation[k].target->module->type) {
                 target_module = ((struct lys_submodule *)mod_iter->deviation[k].target->module)->belongsto;
             } else {
                 target_module = mod_iter->deviation[k].target->module;
             }

             /* we found a module deviating our module */
             if (target_module == cur_mod) {
                 cont = lyd_new(parent, NULL, "deviation");
                 if (!cont) {
                     return EXIT_FAILURE;
                 }

                 if (!lyd_new_leaf(cont, NULL, "name", mod_iter->name)) {
                     return EXIT_FAILURE;
                 }
                 if (!lyd_new_leaf(cont, NULL, "revision", (mod_iter->rev_size ? mod_iter->rev[0].date : ""))) {
                     return EXIT_FAILURE;
                 }
             }
         }

         for (j = 0; j < mod_iter->inc_size; ++j) {
             for (k = 0; k < mod_iter->inc[j].submodule->deviation_size; ++k) {
                 if (mod_iter->inc[j].submodule->deviation[k].target->module->type) {
                     target_module = ((struct lys_submodule *)
                                     mod_iter->inc[j].submodule->deviation[k].target->module)->belongsto;
                 } else {
                     target_module = mod_iter->inc[j].submodule->deviation[k].target->module;
                 }

                 /* we found a submodule deviating our module */
                 if (target_module == cur_mod) {
                     cont = lyd_new(parent, NULL, "deviation");
                     if (!cont) {
                         return EXIT_FAILURE;
                     }

                     if (!lyd_new_leaf(cont, NULL, "name", mod_iter->inc[j].submodule->name)) {
                         return EXIT_FAILURE;
                     }
                     if (!lyd_new_leaf(cont, NULL, "revision",
                                           (mod_iter->inc[j].submodule->rev_size ?
                                            mod_iter->inc[j].submodule->rev[0].date : ""))) {
                         return EXIT_FAILURE;
                     }
                 }
             }
         }
     }

     return EXIT_SUCCESS;
 }

 static int
 ylib_submodules(struct lyd_node *parent, struct lys_module *cur_mod)
 {
     int i;
     struct lyd_node *cont, *item;

     if (cur_mod->inc_size) {
         cont = lyd_new(parent, NULL, "submodules");
     }

     for (i = 0; i < cur_mod->inc_size; ++i) {
         item = lyd_new(cont, NULL, "submodule");
         if (!item) {
             return EXIT_FAILURE;
         }

         if (!lyd_new_leaf(item, NULL, "name", cur_mod->inc[i].submodule->name)) {
             return EXIT_FAILURE;
         }
         if (!lyd_new_leaf(item, NULL, "revision", (cur_mod->inc[i].submodule->rev_size ?
                           cur_mod->inc[i].submodule->rev[0].date : ""))) {
             return EXIT_FAILURE;
         }
         if (cur_mod->inc[i].submodule->uri
                 && !lyd_new_leaf(item, NULL, "schema", cur_mod->inc[i].submodule->uri)) {
             return EXIT_FAILURE;
         }
     }

     return EXIT_SUCCESS;
 }

 API struct lyd_node *
 ly_ctx_info(struct ly_ctx *ctx)
 {
     int i;
     char id[8];
     const struct lys_module *mod;
     struct lyd_node *root, *cont;

     mod = ly_ctx_get_module(ctx, "ietf-yang-library", NULL);
     if (!mod) {
         mod = lyp_search_file(ctx, NULL, "ietf-yang-library", NULL);
     }
     if (!mod || !mod->data || strcmp(mod->data->next->name, "modules")) {
         return NULL;
     }

     root = lyd_new(NULL, mod, "modules");
     if (!root) {
         return NULL;
     }

     for (i = 0; i < ctx->models.used; ++i) {
         cont = lyd_new(root, NULL, "module");
         if (!cont) {
             lyd_free(root);
             return NULL;
         }

         if (!lyd_new_leaf(cont, NULL, "name", ctx->models.list[i]->name)) {
             lyd_free(root);
             return NULL;
         }
         if (!lyd_new_leaf(cont, NULL, "revision", (ctx->models.list[i]->rev_size ?
                               ctx->models.list[i]->rev[0].date : ""))) {
             lyd_free(root);
             return NULL;
         }
         if (ctx->models.list[i]->uri
                 && !lyd_new_leaf(cont, NULL, "schema", ctx->models.list[i]->uri)) {
             lyd_free(root);
             return NULL;
         }
         if (!lyd_new_leaf(cont, NULL, "namespace", ctx->models.list[i]->ns)) {
             lyd_free(root);
             return NULL;
         }
         if (ylib_feature(cont, ctx->models.list[i])) {
             lyd_free(root);
             return NULL;
         }
         if (ylib_deviation(cont, ctx->models.list[i], ctx)) {
             lyd_free(root);
             return NULL;
         }
         if (ctx->models.list[i]->implemented
                 && !lyd_new_leaf(cont, NULL, "conformance", "implement")) {
             lyd_free(root);
             return NULL;
         }
         if (!ctx->models.list[i]->implemented
                 && !lyd_new_leaf(cont, NULL, "conformance", "import")) {
             lyd_free(root);
             return NULL;
         }
         if (ylib_submodules(cont, ctx->models.list[i])) {
             lyd_free(root);
             return NULL;
         }
     }

     sprintf(id, "%u", ctx->models.module_set_id);
     if (!lyd_new_leaf(root, mod, "module-set-id", id)) {
         lyd_free(root);
         return NULL;
     }

     if (lyd_validate(root, 0)) {
         lyd_free(root);
         return NULL;
     }

     return root;
 }
	/**
	* @file context.c
	* @author Radek Krejci <rkrejci@cesnet.cz>
	* @brief context implementation for libyang
	*
	* Copyright (c) 2015 CESNET, z.s.p.o.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	* 3. Neither the name of the Company nor the names of its contributors
	* may be used to endorse or promote products derived from this
	* software without specific prior written permission.
	*/

	#define _GNU_SOURCE
	#include <stddef.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <unistd.h>
	#include <errno.h>
	#include <fcntl.h>

	#include "common.h"
	#include "context.h"
	#include "dict_private.h"
	#include "parser.h"
	#include "tree_internal.h"

	#define IETF_INET_TYPES_PATH "../models/ietf-inet-types@2013-07-15.h"
	#define IETF_YANG_TYPES_PATH "../models/ietf-yang-types@2013-07-15.h"
	#define IETF_YANG_LIB_PATH "../models/ietf-yang-library@2015-07-03.h"

	#include IETF_INET_TYPES_PATH
	#include IETF_YANG_TYPES_PATH
	#include IETF_YANG_LIB_PATH

	API struct ly_ctx *
	ly_ctx_new(const char *search_dir)
	{
	struct ly_ctx *ctx;
	char *cwd;

	ctx = calloc(1, sizeof *ctx);
	if (!ctx) {
	LOGMEM;
	return NULL;
	}

	/* dictionary */
	lydict_init(&ctx->dict);

	/* models list */
	ctx->models.list = calloc(16, sizeof *ctx->models.list);
	if (!ctx->models.list) {
	LOGMEM;
	free(ctx);
	return NULL;
	}
	ctx->models.used = 0;
	ctx->models.size = 16;
	if (search_dir) {
	cwd = get_current_dir_name();
	if (chdir(search_dir)) {
	LOGERR(LY_ESYS, "Unable to use search directory \"%s\" (%s)",
	search_dir, strerror(errno));
	free(cwd);
	ly_ctx_destroy(ctx);
	return NULL;
	}
	ctx->models.search_path = get_current_dir_name();
	chdir(cwd);
	free(cwd);
	}
	ctx->models.module_set_id = 1;

	/* load ietf-inet-types */
	ctx->models.list[0] = (struct lys_module )lys_parse_data(ctx, (char )ietf_inet_types_2013_07_15_yin, LYS_IN_YIN);
	if (!ctx->models.list[0]) {
	ly_ctx_destroy(ctx);
	return NULL;
	}

	/* load ietf-yang-types */
	ctx->models.list[1] = (struct lys_module )lys_parse_data(ctx, (char )ietf_yang_types_2013_07_15_yin, LYS_IN_YIN);
	if (!ctx->models.list[1]) {
	ly_ctx_destroy(ctx);
	return NULL;
	}

	/* load ietf-yang-library */
	ctx->models.list[2] = (struct lys_module )lys_parse_data(ctx, (char )ietf_yang_library_2015_07_03_yin, LYS_IN_YIN);
	if (!ctx->models.list[2]) {
	ly_ctx_destroy(ctx);
	return NULL;
	}

	return ctx;
	}

	API void
	ly_ctx_set_searchdir(struct ly_ctx ctx, const char search_dir)
	{
	char *cwd;

	if (!ctx) {
	return;
	}

	if (search_dir) {
	cwd = get_current_dir_name();
	if (chdir(search_dir)) {
	LOGERR(LY_ESYS, "Unable to use search directory \"%s\" (%s)",
	search_dir, strerror(errno));
	free(cwd);
	return;
	}
	free(ctx->models.search_path);
	ctx->models.search_path = get_current_dir_name();

	chdir(cwd);
	free(cwd);
	} else {
	free(ctx->models.search_path);
	ctx->models.search_path = NULL;
	}
	}

	API const char *
	ly_ctx_get_searchdir(const struct ly_ctx *ctx)
	{
	return ctx->models.search_path;
	}

	API void
	ly_ctx_destroy(struct ly_ctx *ctx)
	{
	if (!ctx) {
	return;
	}

	/* models list */
	while (ctx->models.used) {
	lys_free(ctx->models.list[0], 1);
	}
	free(ctx->models.search_path);
	free(ctx->models.list);

	/* dictionary */
	lydict_clean(&ctx->dict);

	free(ctx);
	}

	API const struct lys_submodule *
	ly_ctx_get_submodule(const struct lys_module module, const char name, const char *revision)
	{
	struct lys_submodule *result;
	int i;

	if (!module \|\| !name) {
	ly_errno = LY_EINVAL;
	return NULL;
	}

	/* TODO search also for submodules not directly available from the main module */

	/* search in modules included by the main module */
	if (module->type) {
	module = ((struct lys_submodule *)module)->belongsto;
	}
	for (i = 0; i < module->inc_size; i++) {
	result = module->inc[i].submodule;
	if (strcmp(name, result->name)) {
	continue;
	}

	if (!revision \|\| (result->rev_size && !strcmp(revision, result->rev[0].date))) {
	return result;
	}
	}

	return NULL;
	}

	static const struct lys_module *
	ly_ctx_get_module_by(const struct ly_ctx ctx, const char key, int offset, const char *revision)
	{
	int i;
	struct lys_module *result = NULL;

	if (!ctx \|\| !key) {
	ly_errno = LY_EINVAL;
	return NULL;
	}

	for (i = 0; i < ctx->models.used; i++) {
	/* use offset to get address of the pointer to string (char**), remember that offset is in
	* bytes, so we have to cast the pointer to the module to (char*), finally, we want to have
	* string not the pointer to string
	*/
	if (!ctx->models.list[i] \|\| strcmp(key, (char)(((char)ctx->models.list[i]) + offset))) {
	continue;
	}

	if (!revision) {
	/* compare revisons and remember the newest one */
	if (result) {
	if (!ctx->models.list[i]->rev_size) {
	/* the current have no revision, keep the previous with some revision */
	continue;
	}
	if (result->rev_size && strcmp(ctx->models.list[i]->rev[0].date, result->rev[0].date) < 0) {
	/* the previous found matching module has a newer revision */
	continue;
	}
	}

	/* remember the current match and search for newer version */
	result = ctx->models.list[i];
	} else {
	if (ctx->models.list[i]->rev_size && !strcmp(revision, ctx->models.list[i]->rev[0].date)) {
	/* matching revision */
	result = ctx->models.list[i];
	break;
	}
	}
	}

	return result;

	}

	API const struct lys_module *
	ly_ctx_get_module_by_ns(const struct ly_ctx ctx, const char ns, const char *revision)
	{
	return ly_ctx_get_module_by(ctx, ns, offsetof(struct lys_module, ns), revision);
	}

	API const struct lys_module *
	ly_ctx_get_module(const struct ly_ctx ctx, const char name, const char *revision)
	{
	return ly_ctx_get_module_by(ctx, name, offsetof(struct lys_module, name), revision);
	}

	API void
	ly_ctx_set_module_clb(struct ly_ctx ctx, ly_module_clb clb, void user_data)
	{
	ctx->module_clb = clb;
	ctx->module_clb_data = user_data;
	}

	API ly_module_clb
	ly_ctx_get_module_clb(const struct ly_ctx ctx, void *user_data)
	{
	if (user_data) {
	*user_data = ctx->module_clb_data;
	}
	return ctx->module_clb;
	}

	API const struct lys_module *
	ly_ctx_load_module(struct ly_ctx ctx, const char name, const char *revision)
	{
	const struct lys_module *module;
	char *module_data;
	void (module_data_free)(char module_data) = NULL;
	LYS_INFORMAT format = LYS_IN_UNKNOWN;

	if (!ctx \|\| !name) {
	ly_errno = LY_EINVAL;
	return NULL;
	}

	if (ctx->module_clb) {
	module_data = ctx->module_clb(name, revision, ctx->module_clb_data, &format, &module_data_free);
	if (!module_data) {
	LOGERR(LY_EVALID, "User module retrieval callback failed!");
	return NULL;
	}
	module = lys_parse_data(ctx, module_data, format);
	if (module_data_free) {
	module_data_free(module_data);
	} else {
	free(module_data);
	}
	} else {
	module = lyp_search_file(ctx, NULL, name, revision);
	}

	return module;
	}

	API const char **
	ly_ctx_get_module_names(const struct ly_ctx *ctx)
	{
	int i;
	const char **result = NULL;

	if (!ctx) {
	ly_errno = LY_EINVAL;
	return NULL;
	}

	result = malloc((ctx->models.used+1) * sizeof *result);
	if (!result) {
	LOGMEM;
	return NULL;
	}

	for (i = 0; i < ctx->models.used; i++) {
	result[i] = ctx->models.list[i]->name;
	}
	result[i] = NULL;

	return result;
	}

	API const char **
	ly_ctx_get_submodule_names(const struct ly_ctx ctx, const char module_name)
	{
	int i;
	const char **result = NULL;
	const struct lys_module *mod;

	if (!ctx) {
	ly_errno = LY_EINVAL;
	return NULL;
	}

	mod = ly_ctx_get_module(ctx, module_name, NULL);
	if (!mod) {
	LOGERR(LY_EVALID, "Data model \"%s\" not loaded", module_name);
	return NULL;
	}

	result = malloc((mod->inc_size+1) * sizeof *result);
	if (!result) {
	LOGMEM;
	return NULL;
	}

	for (i = 0; i < mod->inc_size; i++) {
	result[i] = mod->inc[i].submodule->name;
	}
	result[i] = NULL;

	return result;
	}

	static int
	ylib_feature(struct lyd_node parent, struct lys_module cur_mod)
	{
	int i, j;

	/* module features */
	for (i = 0; i < cur_mod->features_size; ++i) {
	if (!(cur_mod->features[i].flags & LYS_FENABLED)) {
	continue;
	}

	if (!lyd_new_leaf(parent, NULL, "feature", cur_mod->features[i].name)) {
	return EXIT_FAILURE;
	}
	}

	/* submodule features */
	for (i = 0; i < cur_mod->inc_size; ++i) {
	for (j = 0; j < cur_mod->inc[i].submodule->features_size; ++j) {
	if (!(cur_mod->inc[i].submodule->features[j].flags & LYS_FENABLED)) {
	continue;
	}

	if (!lyd_new_leaf(parent, NULL, "feature", cur_mod->inc[i].submodule->features[j].name)) {
	return EXIT_FAILURE;
	}
	}
	}

	return EXIT_SUCCESS;
	}

	static int
	ylib_deviation(struct lyd_node parent, struct lys_module cur_mod, struct ly_ctx *ctx)
	{
	int i, j, k;
	struct lys_module target_module, mod_iter;
	struct lyd_node *cont;

	for (i = 0; i < ctx->models.used; ++i) {
	mod_iter = ctx->models.list[i];
	for (k = 0; k < mod_iter->deviation_size; ++k) {
	if (mod_iter->deviation[k].target->module->type) {
	target_module = ((struct lys_submodule *)mod_iter->deviation[k].target->module)->belongsto;
	} else {
	target_module = mod_iter->deviation[k].target->module;
	}

	/* we found a module deviating our module */
	if (target_module == cur_mod) {
	cont = lyd_new(parent, NULL, "deviation");
	if (!cont) {
	return EXIT_FAILURE;
	}

	if (!lyd_new_leaf(cont, NULL, "name", mod_iter->name)) {
	return EXIT_FAILURE;
	}
	if (!lyd_new_leaf(cont, NULL, "revision", (mod_iter->rev_size ? mod_iter->rev[0].date : ""))) {
	return EXIT_FAILURE;
	}
	}
	}

	for (j = 0; j < mod_iter->inc_size; ++j) {
	for (k = 0; k < mod_iter->inc[j].submodule->deviation_size; ++k) {
	if (mod_iter->inc[j].submodule->deviation[k].target->module->type) {
	target_module = ((struct lys_submodule *)
	mod_iter->inc[j].submodule->deviation[k].target->module)->belongsto;
	} else {
	target_module = mod_iter->inc[j].submodule->deviation[k].target->module;
	}

	/* we found a submodule deviating our module */
	if (target_module == cur_mod) {
	cont = lyd_new(parent, NULL, "deviation");
	if (!cont) {
	return EXIT_FAILURE;
	}

	if (!lyd_new_leaf(cont, NULL, "name", mod_iter->inc[j].submodule->name)) {
	return EXIT_FAILURE;
	}
	if (!lyd_new_leaf(cont, NULL, "revision",
	(mod_iter->inc[j].submodule->rev_size ?
	mod_iter->inc[j].submodule->rev[0].date : ""))) {
	return EXIT_FAILURE;
	}
	}
	}
	}
	}

	return EXIT_SUCCESS;
	}

	static int
	ylib_submodules(struct lyd_node parent, struct lys_module cur_mod)
	{
	int i;
	struct lyd_node cont, item;

	if (cur_mod->inc_size) {
	cont = lyd_new(parent, NULL, "submodules");
	}

	for (i = 0; i < cur_mod->inc_size; ++i) {
	item = lyd_new(cont, NULL, "submodule");
	if (!item) {
	return EXIT_FAILURE;
	}

	if (!lyd_new_leaf(item, NULL, "name", cur_mod->inc[i].submodule->name)) {
	return EXIT_FAILURE;
	}
	if (!lyd_new_leaf(item, NULL, "revision", (cur_mod->inc[i].submodule->rev_size ?
	cur_mod->inc[i].submodule->rev[0].date : ""))) {
	return EXIT_FAILURE;
	}
	if (cur_mod->inc[i].submodule->uri
	&& !lyd_new_leaf(item, NULL, "schema", cur_mod->inc[i].submodule->uri)) {
	return EXIT_FAILURE;
	}
	}

	return EXIT_SUCCESS;
	}

	API struct lyd_node *
	ly_ctx_info(struct ly_ctx *ctx)
	{
	int i;
	char id[8];
	const struct lys_module *mod;
	struct lyd_node root, cont;

	mod = ly_ctx_get_module(ctx, "ietf-yang-library", NULL);
	if (!mod) {
	mod = lyp_search_file(ctx, NULL, "ietf-yang-library", NULL);
	}
	if (!mod \|\| !mod->data \|\| strcmp(mod->data->next->name, "modules")) {
	return NULL;
	}

	root = lyd_new(NULL, mod, "modules");
	if (!root) {
	return NULL;
	}

	for (i = 0; i < ctx->models.used; ++i) {
	cont = lyd_new(root, NULL, "module");
	if (!cont) {
	lyd_free(root);
	return NULL;
	}

	if (!lyd_new_leaf(cont, NULL, "name", ctx->models.list[i]->name)) {
	lyd_free(root);
	return NULL;
	}
	if (!lyd_new_leaf(cont, NULL, "revision", (ctx->models.list[i]->rev_size ?
	ctx->models.list[i]->rev[0].date : ""))) {
	lyd_free(root);
	return NULL;
	}
	if (ctx->models.list[i]->uri
	&& !lyd_new_leaf(cont, NULL, "schema", ctx->models.list[i]->uri)) {
	lyd_free(root);
	return NULL;
	}
	if (!lyd_new_leaf(cont, NULL, "namespace", ctx->models.list[i]->ns)) {
	lyd_free(root);
	return NULL;
	}
	if (ylib_feature(cont, ctx->models.list[i])) {
	lyd_free(root);
	return NULL;
	}
	if (ylib_deviation(cont, ctx->models.list[i], ctx)) {
	lyd_free(root);
	return NULL;
	}
	if (ctx->models.list[i]->implemented
	&& !lyd_new_leaf(cont, NULL, "conformance", "implement")) {
	lyd_free(root);
	return NULL;
	}
	if (!ctx->models.list[i]->implemented
	&& !lyd_new_leaf(cont, NULL, "conformance", "import")) {
	lyd_free(root);
	return NULL;
	}
	if (ylib_submodules(cont, ctx->models.list[i])) {
	lyd_free(root);
	return NULL;
	}
	}

	sprintf(id, "%u", ctx->models.module_set_id);
	if (!lyd_new_leaf(root, mod, "module-set-id", id)) {
	lyd_free(root);
	return NULL;
	}

	if (lyd_validate(root, 0)) {
	lyd_free(root);
	return NULL;
	}

	return root;
	}