From 170ab11075d3be56e89d6444abf1148329130f4b Mon Sep 17 00:00:00 2001 From: Joe Hershberger Date: Tue, 11 Dec 2012 22:16:24 -0600 Subject: env: Add support for callbacks to environment vars Add support for per-variable callbacks to the "hashtable" functions. Signed-off-by: Joe Hershberger !!!fix comment in callback --- common/Makefile | 4 + common/env_attr.c | 222 ++++++++++++++++++++++++++++++++++++++++++++++++++ common/env_callback.c | 144 ++++++++++++++++++++++++++++++++ 3 files changed, 370 insertions(+) create mode 100644 common/env_attr.c create mode 100644 common/env_callback.c (limited to 'common') diff --git a/common/Makefile b/common/Makefile index ce30359..04812e9 100644 --- a/common/Makefile +++ b/common/Makefile @@ -44,6 +44,8 @@ COBJS-y += cmd_nvedit.o COBJS-y += cmd_version.o # environment +COBJS-y += env_attr.o +COBJS-y += env_callback.o COBJS-y += env_common.o COBJS-$(CONFIG_ENV_IS_IN_DATAFLASH) += env_dataflash.o COBJS-$(CONFIG_ENV_IS_IN_EEPROM) += env_eeprom.o @@ -207,6 +209,8 @@ COBJS-y += env_common.o COBJS-$(CONFIG_ENV_IS_IN_FLASH) += env_flash.o COBJS-$(CONFIG_SPL_YMODEM_SUPPORT) += xyzModem.o COBJS-$(CONFIG_SPL_NET_SUPPORT) += cmd_nvedit.o +COBJS-$(CONFIG_SPL_NET_SUPPORT) += env_attr.o +COBJS-$(CONFIG_SPL_NET_SUPPORT) += env_callback.o COBJS-$(CONFIG_SPL_NET_SUPPORT) += env_common.o COBJS-$(CONFIG_SPL_NET_SUPPORT) += env_nowhere.o COBJS-$(CONFIG_SPL_NET_SUPPORT) += miiphyutil.o diff --git a/common/env_attr.c b/common/env_attr.c new file mode 100644 index 0000000..7d330a5 --- /dev/null +++ b/common/env_attr.c @@ -0,0 +1,222 @@ +/* + * (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 +#include +#include +#include +#include + +/* + * Iterate through the whole list calling the callback for each found element. + * "attr_list" takes the form: + * attributes = [^,:\s]* + * entry = name[:attributes] + * list = entry[,list] + */ +int env_attr_walk(const char *attr_list, + int (*callback)(const char *name, const char *attributes)) +{ + const char *entry, *entry_end; + char *name, *attributes; + + if (!attr_list) + /* list not found */ + return 1; + + entry = attr_list; + do { + char *entry_cpy = NULL; + + entry_end = strchr(entry, ENV_ATTR_LIST_DELIM); + /* check if this is the last entry in the list */ + if (entry_end == NULL) { + int entry_len = strlen(entry); + + if (entry_len) { + /* + * allocate memory to copy the entry into since + * we will need to inject '\0' chars and squash + * white-space before calling the callback + */ + entry_cpy = malloc(entry_len + 1); + if (entry_cpy) + /* copy the rest of the list */ + strcpy(entry_cpy, entry); + else + return -ENOMEM; + } + } else { + int entry_len = entry_end - entry; + + if (entry_len) { + /* + * allocate memory to copy the entry into since + * we will need to inject '\0' chars and squash + * white-space before calling the callback + */ + entry_cpy = malloc(entry_len + 1); + if (entry_cpy) { + /* copy just this entry and null term */ + strncpy(entry_cpy, entry, entry_len); + entry_cpy[entry_len] = '\0'; + } else + return -ENOMEM; + } + } + + /* check if there is anything to process (e.g. not ",,,") */ + if (entry_cpy != NULL) { + attributes = strchr(entry_cpy, ENV_ATTR_SEP); + /* check if there is a ':' */ + if (attributes != NULL) { + /* replace the ':' with '\0' to term name */ + *attributes++ = '\0'; + /* remove white-space from attributes */ + attributes = strim(attributes); + } + /* remove white-space from name */ + name = strim(entry_cpy); + + /* only call the callback if there is a name */ + if (strlen(name) != 0) { + int retval = 0; + + retval = callback(name, attributes); + if (retval) { + free(entry_cpy); + return retval; + } + } + } + + free(entry_cpy); + entry = entry_end + 1; + } while (entry_end != NULL); + + return 0; +} + +/* + * Search for the last matching string in another string with the option to + * start looking at a certain point (i.e. ignore anything beyond that point). + */ +static char *reverse_strstr(const char *searched, const char *search_for, + const char *searched_start) +{ + char *result = NULL; + + if (*search_for == '\0') + return (char *)searched; + + for (;;) { + char *match = strstr(searched, search_for); + + /* + * Stop looking if no new match is found or looking past the + * searched_start pointer + */ + if (match == NULL || (searched_start != NULL && + match + strlen(search_for) > searched_start)) + break; + + result = match; + searched = match + 1; + } + + return result; +} + +/* + * Retrieve the attributes string associated with a single name in the list + * There is no protection on attributes being too small for the value + */ +int env_attr_lookup(const char *attr_list, const char *name, char *attributes) +{ + const char *entry = NULL; + + if (!attributes) + /* bad parameter */ + return -1; + if (!attr_list) + /* list not found */ + return 1; + + entry = reverse_strstr(attr_list, name, NULL); + while (entry != NULL) { + const char *prevch = entry - 1; + const char *nextch = entry + strlen(name); + + /* Skip spaces */ + while (*prevch == ' ') + prevch--; + while (*nextch == ' ') + nextch++; + + /* check for an exact match */ + if ((entry == attr_list || + *prevch == ENV_ATTR_LIST_DELIM) && + (*nextch == ENV_ATTR_SEP || + *nextch == ENV_ATTR_LIST_DELIM || + *nextch == '\0')) + break; + + entry = reverse_strstr(attr_list, name, entry); + } + if (entry != NULL) { + int len; + + /* skip the name */ + entry += strlen(name); + /* skip spaces */ + while (*entry == ' ') + entry++; + if (*entry != ENV_ATTR_SEP) + len = 0; + else { + const char *delim; + static const char delims[] = { + ENV_ATTR_LIST_DELIM, ' ', '\0'}; + + /* skip the attr sep */ + entry += 1; + /* skip spaces */ + while (*entry == ' ') + entry++; + + delim = strpbrk(entry, delims); + if (delim == NULL) + len = strlen(entry); + else + len = delim - entry; + memcpy(attributes, entry, len); + } + attributes[len] = '\0'; + + /* success */ + return 0; + } + + /* not found in list */ + return 2; +} diff --git a/common/env_callback.c b/common/env_callback.c new file mode 100644 index 0000000..78ca367 --- /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 +#include + +#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); -- cgit v1.1