[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;
}

static int first_call = 1;
static const char *callback_list;

/*
 * 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;
	char callback_name[256] = "";
	struct env_clbk_tbl *clbkp;
	int ret = 1;

	if (first_call) {
		callback_list = getenv(ENV_CALLBACK_VAR);
		first_call = 0;
	}

	/* 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, void *priv)
{
	ENTRY e, *ep;
	struct env_clbk_tbl *clbkp;

	e.key	= name;
	e.data	= NULL;
	e.callback = 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, NULL);
	/* configure any dynamic callback bindings */
	env_attr_walk(value, set_callback, NULL);

	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
1b610271 HS	38	static int first_call = 1;
	39	static const char *callback_list;
	40
170ab110 JH	41	/*
	42	* Look for a possible callback for a newly added variable
	43	* This is called specifically when the variable did not exist in the hash
	44	* previously, so the blanket update did not find this variable.
	45	*/
	46	void env_callback_init(ENTRY *var_entry)
	47	{
	48	const char *var_name = var_entry->key;
170ab110 JH	49	char callback_name[256] = "";
	50	struct env_clbk_tbl *clbkp;
	51	int ret = 1;
	52
1b610271 HS	53	if (first_call) {
	54	callback_list = getenv(ENV_CALLBACK_VAR);
	55	first_call = 0;
	56	}
	57
170ab110 JH	58	/* look in the ".callbacks" var for a reference to this variable */
	59	if (callback_list != NULL)
	60	ret = env_attr_lookup(callback_list, var_name, callback_name);
	61
	62	/* only if not found there, look in the static list */
	63	if (ret)
	64	ret = env_attr_lookup(ENV_CALLBACK_LIST_STATIC, var_name,
	65	callback_name);
	66
	67	/* if an association was found, set the callback pointer */
	68	if (!ret && strlen(callback_name)) {
	69	clbkp = find_env_callback(callback_name);
	70	if (clbkp != NULL)
	71	#if defined(CONFIG_NEEDS_MANUAL_RELOC)
	72	var_entry->callback = clbkp->callback + gd->reloc_off;
	73	#else
	74	var_entry->callback = clbkp->callback;
	75	#endif
	76	}
	77	}
	78
	79	/*
	80	* Called on each existing env var prior to the blanket update since removing
	81	* a callback association should remove its callback.
	82	*/
	83	static int clear_callback(ENTRY *entry)
	84	{
	85	entry->callback = NULL;
	86
	87	return 0;
	88	}
	89
	90	/*
	91	* Call for each element in the list that associates variables to callbacks
	92	*/
cca98fd6	93	static int set_callback(const char name, const char value, void *priv)
170ab110 JH	94	{
	95	ENTRY e, *ep;
	96	struct env_clbk_tbl *clbkp;
	97
	98	e.key = name;
	99	e.data = NULL;
5a689439	100	e.callback = NULL;
170ab110 JH	101	hsearch_r(e, FIND, &ep, &env_htab, 0);
	102
	103	/* does the env variable actually exist? */
	104	if (ep != NULL) {
	105	/* the assocaition delares no callback, so remove the pointer */
	106	if (value == NULL \|\| strlen(value) == 0)
	107	ep->callback = NULL;
	108	else {
	109	/* assign the requested callback */
	110	clbkp = find_env_callback(value);
	111	if (clbkp != NULL)
	112	#if defined(CONFIG_NEEDS_MANUAL_RELOC)
	113	ep->callback = clbkp->callback + gd->reloc_off;
	114	#else
	115	ep->callback = clbkp->callback;
	116	#endif
	117	}
	118	}
	119
	120	return 0;
	121	}
	122
	123	static int on_callbacks(const char name, const char value, enum env_op op,
	124	int flags)
	125	{
	126	/* remove all callbacks */
	127	hwalk_r(&env_htab, clear_callback);
	128
	129	/* configure any static callback bindings */
cca98fd6	130	env_attr_walk(ENV_CALLBACK_LIST_STATIC, set_callback, NULL);
170ab110	131	/* configure any dynamic callback bindings */
cca98fd6	132	env_attr_walk(value, set_callback, NULL);
170ab110 JH	133
	134	return 0;
	135	}
	136	U_BOOT_ENV_CALLBACK(callbacks, on_callbacks);