u-boot/common/env_flags.c

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/*
* (C) Copyright 2012
* Joe Hershberger, National Instruments, joe.hershberger@ni.com
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <linux/string.h>
#include <linux/ctype.h>
#ifdef USE_HOSTCC /* Eliminate "ANSI does not permit..." warnings */
#include <stdint.h>
#include <stdio.h>
#include "fw_env.h"
#include <env_attr.h>
#include <env_flags.h>
#define getenv fw_getenv
#else
#include <common.h>
#include <environment.h>
#endif
#ifdef CONFIG_CMD_NET
#define ENV_FLAGS_NET_VARTYPE_REPS "im"
#else
#define ENV_FLAGS_NET_VARTYPE_REPS ""
#endif
static const char env_flags_vartype_rep[] = "sdxb" ENV_FLAGS_NET_VARTYPE_REPS;
static const char env_flags_varaccess_rep[] = "aroc";
static const int env_flags_varaccess_mask[] = {
0,
ENV_FLAGS_VARACCESS_PREVENT_DELETE |
ENV_FLAGS_VARACCESS_PREVENT_CREATE |
ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
ENV_FLAGS_VARACCESS_PREVENT_DELETE |
ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
ENV_FLAGS_VARACCESS_PREVENT_DELETE |
ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR};
#ifdef CONFIG_CMD_ENV_FLAGS
static const char * const env_flags_vartype_names[] = {
"string",
"decimal",
"hexadecimal",
"boolean",
#ifdef CONFIG_CMD_NET
"IP address",
"MAC address",
#endif
};
static const char * const env_flags_varaccess_names[] = {
"any",
"read-only",
"write-once",
"change-default",
};
/*
* Print the whole list of available type flags.
*/
void env_flags_print_vartypes(void)
{
enum env_flags_vartype curtype = (enum env_flags_vartype)0;
while (curtype != env_flags_vartype_end) {
printf("\t%c -\t%s\n", env_flags_vartype_rep[curtype],
env_flags_vartype_names[curtype]);
curtype++;
}
}
/*
* Print the whole list of available access flags.
*/
void env_flags_print_varaccess(void)
{
enum env_flags_varaccess curaccess = (enum env_flags_varaccess)0;
while (curaccess != env_flags_varaccess_end) {
printf("\t%c -\t%s\n", env_flags_varaccess_rep[curaccess],
env_flags_varaccess_names[curaccess]);
curaccess++;
}
}
/*
* Return the name of the type.
*/
const char *env_flags_get_vartype_name(enum env_flags_vartype type)
{
return env_flags_vartype_names[type];
}
/*
* Return the name of the access.
*/
const char *env_flags_get_varaccess_name(enum env_flags_varaccess access)
{
return env_flags_varaccess_names[access];
}
#endif /* CONFIG_CMD_ENV_FLAGS */
/*
* Parse the flags string from a .flags attribute list into the vartype enum.
*/
enum env_flags_vartype env_flags_parse_vartype(const char *flags)
{
char *type;
if (strlen(flags) <= ENV_FLAGS_VARTYPE_LOC)
return env_flags_vartype_string;
type = strchr(env_flags_vartype_rep,
flags[ENV_FLAGS_VARTYPE_LOC]);
if (type != NULL)
return (enum env_flags_vartype)
(type - &env_flags_vartype_rep[0]);
printf("## Warning: Unknown environment variable type '%c'\n",
flags[ENV_FLAGS_VARTYPE_LOC]);
return env_flags_vartype_string;
}
/*
* Parse the flags string from a .flags attribute list into the varaccess enum.
*/
enum env_flags_varaccess env_flags_parse_varaccess(const char *flags)
{
char *access;
if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
return env_flags_varaccess_any;
access = strchr(env_flags_varaccess_rep,
flags[ENV_FLAGS_VARACCESS_LOC]);
if (access != NULL)
return (enum env_flags_varaccess)
(access - &env_flags_varaccess_rep[0]);
printf("## Warning: Unknown environment variable access method '%c'\n",
flags[ENV_FLAGS_VARACCESS_LOC]);
return env_flags_varaccess_any;
}
/*
* Parse the binary flags from a hash table entry into the varaccess enum.
*/
enum env_flags_varaccess env_flags_parse_varaccess_from_binflags(int binflags)
{
int i;
for (i = 0; i < sizeof(env_flags_varaccess_mask); i++)
if (env_flags_varaccess_mask[i] ==
(binflags & ENV_FLAGS_VARACCESS_BIN_MASK))
return (enum env_flags_varaccess)i;
printf("Warning: Non-standard access flags. (0x%x)\n",
binflags & ENV_FLAGS_VARACCESS_BIN_MASK);
return env_flags_varaccess_any;
}
static inline int is_hex_prefix(const char *value)
{
return value[0] == '0' && (value[1] == 'x' || value[1] == 'X');
}
static void skip_num(int hex, const char *value, const char **end,
int max_digits)
{
int i;
if (hex && is_hex_prefix(value))
value += 2;
for (i = max_digits; i != 0; i--) {
if (hex && !isxdigit(*value))
break;
if (!hex && !isdigit(*value))
break;
value++;
}
if (end != NULL)
*end = value;
}
/*
* Based on the declared type enum, validate that the value string complies
* with that format
*/
static int _env_flags_validate_type(const char *value,
enum env_flags_vartype type)
{
const char *end;
#ifdef CONFIG_CMD_NET
const char *cur;
int i;
#endif
switch (type) {
case env_flags_vartype_string:
break;
case env_flags_vartype_decimal:
skip_num(0, value, &end, -1);
if (*end != '\0')
return -1;
break;
case env_flags_vartype_hex:
skip_num(1, value, &end, -1);
if (*end != '\0')
return -1;
if (value + 2 == end && is_hex_prefix(value))
return -1;
break;
case env_flags_vartype_bool:
if (value[0] != '1' && value[0] != 'y' && value[0] != 't' &&
value[0] != 'Y' && value[0] != 'T' &&
value[0] != '0' && value[0] != 'n' && value[0] != 'f' &&
value[0] != 'N' && value[0] != 'F')
return -1;
if (value[1] != '\0')
return -1;
break;
#ifdef CONFIG_CMD_NET
case env_flags_vartype_ipaddr:
cur = value;
for (i = 0; i < 4; i++) {
skip_num(0, cur, &end, 3);
if (cur == end)
return -1;
if (i != 3 && *end != '.')
return -1;
if (i == 3 && *end != '\0')
return -1;
cur = end + 1;
}
break;
case env_flags_vartype_macaddr:
cur = value;
for (i = 0; i < 6; i++) {
skip_num(1, cur, &end, 2);
if (cur == end)
return -1;
if (cur + 2 == end && is_hex_prefix(cur))
return -1;
if (i != 5 && *end != ':')
return -1;
if (i == 5 && *end != '\0')
return -1;
cur = end + 1;
}
break;
#endif
case env_flags_vartype_end:
return -1;
}
/* OK */
return 0;
}
/*
* Look for flags in a provided list and failing that the static list
*/
static inline int env_flags_lookup(const char *flags_list, const char *name,
char *flags)
{
int ret = 1;
if (!flags)
/* bad parameter */
return -1;
/* try the env first */
if (flags_list)
ret = env_attr_lookup(flags_list, name, flags);
if (ret != 0)
/* if not found in the env, look in the static list */
ret = env_attr_lookup(ENV_FLAGS_LIST_STATIC, name, flags);
return ret;
}
#ifdef USE_HOSTCC /* Functions only used from tools/env */
/*
* Look up any flags directly from the .flags variable and the static list
* and convert them to the vartype enum.
*/
enum env_flags_vartype env_flags_get_type(const char *name)
{
const char *flags_list = getenv(ENV_FLAGS_VAR);
char flags[ENV_FLAGS_ATTR_MAX_LEN + 1];
if (env_flags_lookup(flags_list, name, flags))
return env_flags_vartype_string;
if (strlen(flags) <= ENV_FLAGS_VARTYPE_LOC)
return env_flags_vartype_string;
return env_flags_parse_vartype(flags);
}
/*
* Look up the access of a variable directly from the .flags var.
*/
enum env_flags_varaccess env_flags_get_varaccess(const char *name)
{
const char *flags_list = getenv(ENV_FLAGS_VAR);
char flags[ENV_FLAGS_ATTR_MAX_LEN + 1];
if (env_flags_lookup(flags_list, name, flags))
return env_flags_varaccess_any;
if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
return env_flags_varaccess_any;
return env_flags_parse_varaccess(flags);
}
/*
* Validate that the proposed new value for "name" is valid according to the
* defined flags for that variable, if any.
*/
int env_flags_validate_type(const char *name, const char *value)
{
enum env_flags_vartype type;
if (value == NULL)
return 0;
type = env_flags_get_type(name);
if (_env_flags_validate_type(value, type) < 0) {
printf("## Error: flags type check failure for "
"\"%s\" <= \"%s\" (type: %c)\n",
name, value, env_flags_vartype_rep[type]);
return -1;
}
return 0;
}
/*
* Validate that the proposed access to variable "name" is valid according to
* the defined flags for that variable, if any.
*/
int env_flags_validate_varaccess(const char *name, int check_mask)
{
enum env_flags_varaccess access;
int access_mask;
access = env_flags_get_varaccess(name);
access_mask = env_flags_varaccess_mask[access];
return (check_mask & access_mask) != 0;
}
/*
* Validate the parameters to "env set" directly
*/
int env_flags_validate_env_set_params(int argc, char * const argv[])
{
if ((argc >= 3) && argv[2] != NULL) {
enum env_flags_vartype type = env_flags_get_type(argv[1]);
/*
* we don't currently check types that need more than
* one argument
*/
if (type != env_flags_vartype_string && argc > 3) {
printf("## Error: too many parameters for setting "
"\"%s\"\n", argv[1]);
return -1;
}
return env_flags_validate_type(argv[1], argv[2]);
}
/* ok */
return 0;
}
#else /* !USE_HOSTCC - Functions only used from lib/hashtable.c */
/*
* Parse the flag charachters from the .flags attribute list into the binary
* form to be stored in the environment entry->flags field.
*/
static int env_parse_flags_to_bin(const char *flags)
{
int binflags;
binflags = env_flags_parse_vartype(flags) & ENV_FLAGS_VARTYPE_BIN_MASK;
binflags |= env_flags_varaccess_mask[env_flags_parse_varaccess(flags)];
return binflags;
}
static int first_call = 1;
static const char *flags_list;
/*
* Look for possible flags 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_flags_init(ENTRY *var_entry)
{
const char *var_name = var_entry->key;
char flags[ENV_FLAGS_ATTR_MAX_LEN + 1] = "";
int ret = 1;
if (first_call) {
flags_list = getenv(ENV_FLAGS_VAR);
first_call = 0;
}
/* look in the ".flags" and static for a reference to this variable */
ret = env_flags_lookup(flags_list, var_name, flags);
/* if any flags were found, set the binary form to the entry */
if (!ret && strlen(flags))
var_entry->flags = env_parse_flags_to_bin(flags);
}
/*
* Called on each existing env var prior to the blanket update since removing
* a flag in the flag list should remove its flags.
*/
static int clear_flags(ENTRY *entry)
{
entry->flags = 0;
return 0;
}
/*
* Call for each element in the list that defines flags for a variable
*/
static int set_flags(const char *name, const char *value, void *priv)
{
ENTRY e, *ep;
e.key = name;
e.data = NULL;
hsearch_r(e, FIND, &ep, &env_htab, 0);
/* does the env variable actually exist? */
if (ep != NULL) {
/* the flag list is empty, so clear the flags */
if (value == NULL || strlen(value) == 0)
ep->flags = 0;
else
/* assign the requested flags */
ep->flags = env_parse_flags_to_bin(value);
}
return 0;
}
static int on_flags(const char *name, const char *value, enum env_op op,
int flags)
{
/* remove all flags */
hwalk_r(&env_htab, clear_flags);
/* configure any static flags */
env_attr_walk(ENV_FLAGS_LIST_STATIC, set_flags, NULL);
/* configure any dynamic flags */
env_attr_walk(value, set_flags, NULL);
return 0;
}
U_BOOT_ENV_CALLBACK(flags, on_flags);
/*
* Perform consistency checking before creating, overwriting, or deleting an
* environment variable. Called as a callback function by hsearch_r() and
* hdelete_r(). Returns 0 in case of success, 1 in case of failure.
* When (flag & H_FORCE) is set, do not print out any error message and force
* overwriting of write-once variables.
*/
int env_flags_validate(const ENTRY *item, const char *newval, enum env_op op,
int flag)
{
const char *name;
const char *oldval = NULL;
if (op != env_op_create)
oldval = item->data;
name = item->key;
/* Default value for NULL to protect string-manipulating functions */
newval = newval ? : "";
/* validate the value to match the variable type */
if (op != env_op_delete) {
enum env_flags_vartype type = (enum env_flags_vartype)
(ENV_FLAGS_VARTYPE_BIN_MASK & item->flags);
if (_env_flags_validate_type(newval, type) < 0) {
printf("## Error: flags type check failure for "
"\"%s\" <= \"%s\" (type: %c)\n",
name, newval, env_flags_vartype_rep[type]);
return -1;
}
}
/* check for access permission */
#ifndef CONFIG_ENV_ACCESS_IGNORE_FORCE
if (flag & H_FORCE)
return 0;
#endif
switch (op) {
case env_op_delete:
if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_DELETE) {
printf("## Error: Can't delete \"%s\"\n", name);
return 1;
}
break;
case env_op_overwrite:
if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_OVERWR) {
printf("## Error: Can't overwrite \"%s\"\n", name);
return 1;
} else if (item->flags &
ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR) {
const char *defval = getenv_default(name);
if (defval == NULL)
defval = "";
printf("oldval: %s defval: %s\n", oldval, defval);
if (strcmp(oldval, defval) != 0) {
printf("## Error: Can't overwrite \"%s\"\n",
name);
return 1;
}
}
break;
case env_op_create:
if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_CREATE) {
printf("## Error: Can't create \"%s\"\n", name);
return 1;
}
break;
}
return 0;
}
#endif