diff options
Diffstat (limited to 'common/env_callback.c')
| -rw-r--r-- | common/env_callback.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/common/env_callback.c b/common/env_callback.c new file mode 100644 index 0000000000..78ca3674f0 --- /dev/null +++ b/common/env_callback.c @@ -0,0 +1,144 @@ +/* + * (C) Copyright 2012 + * Joe Hershberger, National Instruments, joe.hershberger@ni.com + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#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 + */ +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); |