137 lines
3.2 KiB
C
137 lines
3.2 KiB
C
/*
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* (C) Copyright 2012
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* Joe Hershberger, National Instruments, joe.hershberger@ni.com
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <environment.h>
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#if defined(CONFIG_NEEDS_MANUAL_RELOC)
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DECLARE_GLOBAL_DATA_PTR;
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#endif
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/*
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* Look up a callback function pointer by name
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*/
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static struct env_clbk_tbl *find_env_callback(const char *name)
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{
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struct env_clbk_tbl *clbkp;
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int i;
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int num_callbacks = ll_entry_count(struct env_clbk_tbl, env_clbk);
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if (name == NULL)
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return NULL;
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/* look up the callback in the linker-list */
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for (i = 0, clbkp = ll_entry_start(struct env_clbk_tbl, env_clbk);
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i < num_callbacks;
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i++, clbkp++) {
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if (strcmp(name, clbkp->name) == 0)
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return clbkp;
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}
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return NULL;
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}
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static int first_call = 1;
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static const char *callback_list;
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/*
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* Look for a possible callback for a newly added variable
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* This is called specifically when the variable did not exist in the hash
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* previously, so the blanket update did not find this variable.
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*/
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void env_callback_init(ENTRY *var_entry)
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{
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const char *var_name = var_entry->key;
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char callback_name[256] = "";
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struct env_clbk_tbl *clbkp;
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int ret = 1;
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if (first_call) {
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callback_list = getenv(ENV_CALLBACK_VAR);
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first_call = 0;
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}
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/* look in the ".callbacks" var for a reference to this variable */
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if (callback_list != NULL)
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ret = env_attr_lookup(callback_list, var_name, callback_name);
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/* only if not found there, look in the static list */
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if (ret)
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ret = env_attr_lookup(ENV_CALLBACK_LIST_STATIC, var_name,
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callback_name);
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/* if an association was found, set the callback pointer */
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if (!ret && strlen(callback_name)) {
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clbkp = find_env_callback(callback_name);
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if (clbkp != NULL)
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#if defined(CONFIG_NEEDS_MANUAL_RELOC)
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var_entry->callback = clbkp->callback + gd->reloc_off;
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#else
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var_entry->callback = clbkp->callback;
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#endif
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}
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}
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/*
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* Called on each existing env var prior to the blanket update since removing
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* a callback association should remove its callback.
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*/
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static int clear_callback(ENTRY *entry)
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{
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entry->callback = NULL;
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return 0;
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}
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/*
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* Call for each element in the list that associates variables to callbacks
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*/
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static int set_callback(const char *name, const char *value, void *priv)
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{
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ENTRY e, *ep;
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struct env_clbk_tbl *clbkp;
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e.key = name;
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e.data = NULL;
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e.callback = NULL;
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hsearch_r(e, FIND, &ep, &env_htab, 0);
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/* does the env variable actually exist? */
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if (ep != NULL) {
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/* the assocaition delares no callback, so remove the pointer */
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if (value == NULL || strlen(value) == 0)
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ep->callback = NULL;
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else {
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/* assign the requested callback */
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clbkp = find_env_callback(value);
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if (clbkp != NULL)
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#if defined(CONFIG_NEEDS_MANUAL_RELOC)
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ep->callback = clbkp->callback + gd->reloc_off;
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#else
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ep->callback = clbkp->callback;
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#endif
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}
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}
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return 0;
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}
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static int on_callbacks(const char *name, const char *value, enum env_op op,
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int flags)
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{
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/* remove all callbacks */
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hwalk_r(&env_htab, clear_callback);
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/* configure any static callback bindings */
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env_attr_walk(ENV_CALLBACK_LIST_STATIC, set_callback, NULL);
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/* configure any dynamic callback bindings */
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env_attr_walk(value, set_callback, NULL);
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return 0;
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}
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U_BOOT_ENV_CALLBACK(callbacks, on_callbacks);
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