[people/ms/u-boot.git] / common / env_callback.c

/*
 * (C) Copyright 2012
 * Joe Hershberger, National Instruments, joe.hershberger@ni.com
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <environment.h>

#if defined(CONFIG_NEEDS_MANUAL_RELOC)
DECLARE_GLOBAL_DATA_PTR;
#endif

/*
 * Look up a callback function pointer by name
 */
static struct env_clbk_tbl *find_env_callback(const char *name)
{
	struct env_clbk_tbl *clbkp;
	int i;
	int num_callbacks = ll_entry_count(struct env_clbk_tbl, env_clbk);

	if (name == NULL)
		return NULL;

	/* look up the callback in the linker-list */
	for (i = 0, clbkp = ll_entry_start(struct env_clbk_tbl, env_clbk);
	     i < num_callbacks;
	     i++, clbkp++) {
		if (strcmp(name, clbkp->name) == 0)
			return clbkp;
	}

	return NULL;
}

/*
 * Look for a possible callback for a newly added variable
 * This is called specifically when the variable did not exist in the hash
 * previously, so the blanket update did not find this variable.
 */
void env_callback_init(ENTRY *var_entry)
{
	const char *var_name = var_entry->key;
	const char *callback_list = getenv(ENV_CALLBACK_VAR);
	char callback_name[256] = "";
	struct env_clbk_tbl *clbkp;
	int ret = 1;

	/* look in the ".callbacks" var for a reference to this variable */
	if (callback_list != NULL)
		ret = env_attr_lookup(callback_list, var_name, callback_name);

	/* only if not found there, look in the static list */
	if (ret)
		ret = env_attr_lookup(ENV_CALLBACK_LIST_STATIC, var_name,
			callback_name);

	/* if an association was found, set the callback pointer */
	if (!ret && strlen(callback_name)) {
		clbkp = find_env_callback(callback_name);
		if (clbkp != NULL)
#if defined(CONFIG_NEEDS_MANUAL_RELOC)
			var_entry->callback = clbkp->callback + gd->reloc_off;
#else
			var_entry->callback = clbkp->callback;
#endif
	}
}

/*
 * Called on each existing env var prior to the blanket update since removing
 * a callback association should remove its callback.
 */
static int clear_callback(ENTRY *entry)
{
	entry->callback = NULL;

	return 0;
}

/*
 * Call for each element in the list that associates variables to callbacks
 */
static int set_callback(const char *name, const char *value)
{
	ENTRY e, *ep;
	struct env_clbk_tbl *clbkp;

	e.key	= name;
	e.data	= NULL;
	hsearch_r(e, FIND, &ep, &env_htab, 0);

	/* does the env variable actually exist? */
	if (ep != NULL) {
		/* the assocaition delares no callback, so remove the pointer */
		if (value == NULL || strlen(value) == 0)
			ep->callback = NULL;
		else {
			/* assign the requested callback */
			clbkp = find_env_callback(value);
			if (clbkp != NULL)
#if defined(CONFIG_NEEDS_MANUAL_RELOC)
				ep->callback = clbkp->callback + gd->reloc_off;
#else
				ep->callback = clbkp->callback;
#endif
		}
	}

	return 0;
}

static int on_callbacks(const char *name, const char *value, enum env_op op,
	int flags)
{
	/* remove all callbacks */
	hwalk_r(&env_htab, clear_callback);

	/* configure any static callback bindings */
	env_attr_walk(ENV_CALLBACK_LIST_STATIC, set_callback);
	/* configure any dynamic callback bindings */
	env_attr_walk(value, set_callback);

	return 0;
}
U_BOOT_ENV_CALLBACK(callbacks, on_callbacks);
Commit	Line	Data
170ab110 JH	1	/*
	2	* (C) Copyright 2012
	3	* Joe Hershberger, National Instruments, joe.hershberger@ni.com
	4	*
1a459660	5	* SPDX-License-Identifier: GPL-2.0+
170ab110 JH	6	*/
	7
	8	#include <common.h>
	9	#include <environment.h>
	10
	11	#if defined(CONFIG_NEEDS_MANUAL_RELOC)
	12	DECLARE_GLOBAL_DATA_PTR;
	13	#endif
	14
	15	/*
	16	* Look up a callback function pointer by name
	17	*/
268d966d	18	static struct env_clbk_tbl find_env_callback(const char name)
170ab110 JH	19	{
	20	struct env_clbk_tbl *clbkp;
	21	int i;
	22	int num_callbacks = ll_entry_count(struct env_clbk_tbl, env_clbk);
	23
	24	if (name == NULL)
	25	return NULL;
	26
	27	/* look up the callback in the linker-list */
	28	for (i = 0, clbkp = ll_entry_start(struct env_clbk_tbl, env_clbk);
	29	i < num_callbacks;
	30	i++, clbkp++) {
	31	if (strcmp(name, clbkp->name) == 0)
	32	return clbkp;
	33	}
	34
	35	return NULL;
	36	}
	37
	38	/*
	39	* Look for a possible callback for a newly added variable
	40	* This is called specifically when the variable did not exist in the hash
	41	* previously, so the blanket update did not find this variable.
	42	*/
	43	void env_callback_init(ENTRY *var_entry)
	44	{
	45	const char *var_name = var_entry->key;
	46	const char *callback_list = getenv(ENV_CALLBACK_VAR);
	47	char callback_name[256] = "";
	48	struct env_clbk_tbl *clbkp;
	49	int ret = 1;
	50
	51	/* look in the ".callbacks" var for a reference to this variable */
	52	if (callback_list != NULL)
	53	ret = env_attr_lookup(callback_list, var_name, callback_name);
	54
	55	/* only if not found there, look in the static list */
	56	if (ret)
	57	ret = env_attr_lookup(ENV_CALLBACK_LIST_STATIC, var_name,
	58	callback_name);
	59
	60	/* if an association was found, set the callback pointer */
	61	if (!ret && strlen(callback_name)) {
	62	clbkp = find_env_callback(callback_name);
	63	if (clbkp != NULL)
	64	#if defined(CONFIG_NEEDS_MANUAL_RELOC)
	65	var_entry->callback = clbkp->callback + gd->reloc_off;
	66	#else
	67	var_entry->callback = clbkp->callback;
	68	#endif
	69	}
	70	}
	71
	72	/*
	73	* Called on each existing env var prior to the blanket update since removing
	74	* a callback association should remove its callback.
	75	*/
	76	static int clear_callback(ENTRY *entry)
	77	{
	78	entry->callback = NULL;
	79
	80	return 0;
	81	}
	82
83	/*
84	* Call for each element in the list that associates variables to callbacks
85	*/
86	static int set_callback(const char name, const char value)
87	{
88	ENTRY e, *ep;
89	struct env_clbk_tbl *clbkp;
90
91	e.key = name;
92	e.data = NULL;
93	hsearch_r(e, FIND, &ep, &env_htab, 0);
94
95	/* does the env variable actually exist? */
96	if (ep != NULL) {
97	/* the assocaition delares no callback, so remove the pointer */
98	if (value == NULL \|\| strlen(value) == 0)
99	ep->callback = NULL;
100	else {
101	/* assign the requested callback */
102	clbkp = find_env_callback(value);
103	if (clbkp != NULL)
104	#if defined(CONFIG_NEEDS_MANUAL_RELOC)
105	ep->callback = clbkp->callback + gd->reloc_off;
106	#else
107	ep->callback = clbkp->callback;
108	#endif
109	}
110	}
111
112	return 0;
113	}
114
115	static int on_callbacks(const char name, const char value, enum env_op op,
116	int flags)
117	{
118	/* remove all callbacks */
119	hwalk_r(&env_htab, clear_callback);
120
121	/* configure any static callback bindings */
122	env_attr_walk(ENV_CALLBACK_LIST_STATIC, set_callback);
123	/* configure any dynamic callback bindings */
124	env_attr_walk(value, set_callback);
125
126	return 0;
127	}
128	U_BOOT_ENV_CALLBACK(callbacks, on_callbacks);