include/env.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * Common environment functions and definitions
   4  *
   5  * (C) Copyright 2000-2009
   6  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   7  */
   8
   9 #ifndef __ENV_H
  10 #define __ENV_H
  11
  12 #include <compiler.h>
  13 #include <stdbool.h>
  14 #include <linux/types.h>
  15
  16 struct environment_s;
  17
  18 /* Value for environment validity */
  19 enum env_valid {
  20         ENV_INVALID,    /* No valid environment */
  21         ENV_VALID,      /* First or only environment is valid */
  22         ENV_REDUND,     /* Redundant environment is valid */
  23 };
  24
  25 /** enum env_op - environment callback operation */
  26 enum env_op {
  27         env_op_create,
  28         env_op_delete,
  29         env_op_overwrite,
  30 };
  31
  32 /** struct env_clbk_tbl - declares a new callback */
  33 struct env_clbk_tbl {
  34         const char *name;               /* Callback name */
  35         int (*callback)(const char *name, const char *value, enum env_op op,
  36                         int flags);
  37 };
  38
  39 /*
  40  * Define a callback that can be associated with variables.
  41  * when associated through the ".callbacks" environment variable, the callback
  42  * will be executed any time the variable is inserted, overwritten, or deleted.
  43  *
  44  * For SPL these are silently dropped to reduce code size, since environment
  45  * callbacks are not supported with SPL.
  46  */
  47 #ifdef CONFIG_SPL_BUILD
  48 #define U_BOOT_ENV_CALLBACK(name, callback) \
  49         static inline __maybe_unused void _u_boot_env_noop_##name(void) \
  50         { \
  51                 (void)callback; \
  52         }
  53 #else
  54 #define U_BOOT_ENV_CALLBACK(name, callback) \
  55         ll_entry_declare(struct env_clbk_tbl, name, env_clbk) = \
  56         {#name, callback}
  57 #endif
  58
  59 /** enum env_redund_flags - Flags for the redundand_environment */
  60 enum env_redund_flags {
  61         ENV_REDUND_OBSOLETE = 0,
  62         ENV_REDUND_ACTIVE = 1,
  63 };
  64
  65 /**
  66  * env_get_id() - Gets a sequence number for the environment
  67  *
  68  * This value increments every time the environment changes, so can be used an
  69  * an indication of this
  70  *
  71  * Return: environment ID
  72  */
  73 int env_get_id(void);
  74
  75 /**
  76  * env_inc_id() - Increase the sequence number for the environment
  77  *
  78  * Increment the value that is used by env_get_id() to inform callers
  79  * if the environment has changed since they last checked.
  80  */
  81 void env_inc_id(void);
  82
  83 /**
  84  * env_init() - Set up the pre-relocation environment
  85  *
  86  * This locates the environment or uses the default if nothing is available.
  87  * This must be called before env_get() will work.
  88  *
  89  * Return: 0 if OK, -ENODEV if no environment drivers are enabled
  90  */
  91 int env_init(void);
  92
  93 /**
  94  * env_relocate() - Set up the post-relocation environment
  95  *
  96  * This loads the environment into RAM so that it can be modified. This is
  97  * called after relocation, before the environment is used
  98  */
  99 void env_relocate(void);
 100
 101 /**
 102  * env_get() - Look up the value of an environment variable
 103  *
 104  * In U-Boot proper this can be called before relocation (which is when the
 105  * environment is loaded from storage, i.e. GD_FLG_ENV_READY is 0). In that
 106  * case this function calls env_get_f().
 107  *
 108  * @varname:    Variable to look up
 109  * Return: value of variable, or NULL if not found
 110  */
 111 char *env_get(const char *varname);
 112
 113 /*
 114  * Like env_get, but prints an error if envvar isn't defined in the
 115  * environment.  It always returns what env_get does, so it can be used in
 116  * place of env_get without changing error handling otherwise.
 117  *
 118  * @varname:    Variable to look up
 119  * Return: value of variable, or NULL if not found
 120  */
 121 char *from_env(const char *envvar);
 122
 123 /**
 124  * env_get_f() - Look up the value of an environment variable (early)
 125  *
 126  * This function is called from env_get() if the environment has not been
 127  * loaded yet (GD_FLG_ENV_READY flag is 0). Some environment locations will
 128  * support reading the value (slowly) and some will not.
 129  *
 130  * @varname:    Variable to look up
 131  * Return: actual length of the variable value excluding the terminating
 132  *      NULL-byte, or -1 if the variable is not found
 133  */
 134 int env_get_f(const char *name, char *buf, unsigned int len);
 135
 136 /**
 137  * env_get_yesno() - Read an environment variable as a boolean
 138  *
 139  * Return: 1 if yes/true (Y/y/T/t), -1 if variable does not exist (i.e. default
 140  *      to true), 0 if otherwise
 141  */
 142 int env_get_yesno(const char *var);
 143
 144 /**
 145  * env_get_autostart() - Check if autostart is enabled
 146  *
 147  * Return: true if the "autostart" env var exists and is set to "yes"
 148  */
 149 bool env_get_autostart(void);
 150
 151 /**
 152  * env_set() - set an environment variable
 153  *
 154  * This sets or deletes the value of an environment variable. For setting the
 155  * value the variable is created if it does not already exist.
 156  *
 157  * @varname: Variable to adjust
 158  * @value: Value to set for the variable, or NULL or "" to delete the variable
 159  * Return: 0 if OK, 1 on error
 160  */
 161 int env_set(const char *varname, const char *value);
 162
 163 /**
 164  * env_get_ulong() - Return an environment variable as an integer value
 165  *
 166  * Most U-Boot environment variables store hex values. For those which store
 167  * (e.g.) base-10 integers, this function can be used to read the value.
 168  *
 169  * @name:       Variable to look up
 170  * @base:       Base to use (e.g. 10 for base 10, 2 for binary)
 171  * @default_val: Default value to return if no value is found
 172  * Return: the value found, or @default_val if none
 173  */
 174 ulong env_get_ulong(const char *name, int base, ulong default_val);
 175
 176 /**
 177  * env_set_ulong() - set an environment variable to an integer
 178  *
 179  * @varname: Variable to adjust
 180  * @value: Value to set for the variable (will be converted to a string)
 181  * Return: 0 if OK, 1 on error
 182  */
 183 int env_set_ulong(const char *varname, ulong value);
 184
 185 /**
 186  * env_get_hex() - Return an environment variable as a hex value
 187  *
 188  * Decode an environment as a hex number (it may or may not have a 0x
 189  * prefix). If the environment variable cannot be found, or does not start
 190  * with hex digits, the default value is returned.
 191  *
 192  * @varname:            Variable to decode
 193  * @default_val:        Value to return on error
 194  */
 195 ulong env_get_hex(const char *varname, ulong default_val);
 196
 197 /**
 198  * env_set_hex() - set an environment variable to a hex value
 199  *
 200  * @varname: Variable to adjust
 201  * @value: Value to set for the variable (will be converted to a hex string)
 202  * Return: 0 if OK, 1 on error
 203  */
 204 int env_set_hex(const char *varname, ulong value);
 205
 206 /**
 207  * env_set_addr - Set an environment variable to an address in hex
 208  *
 209  * @varname:    Environment variable to set
 210  * @addr:       Value to set it to
 211  * Return: 0 if ok, 1 on error
 212  */
 213 static inline int env_set_addr(const char *varname, const void *addr)
 214 {
 215         return env_set_hex(varname, (ulong)addr);
 216 }
 217
 218 /**
 219  * env_complete() - return an auto-complete for environment variables
 220  *
 221  * @var: partial name to auto-complete
 222  * @maxv: Maximum number of matches to return
 223  * @cmdv: Returns a list of possible matches
 224  * @maxsz: Size of buffer to use for matches
 225  * @buf: Buffer to use for matches
 226  * @dollar_comp: non-zero to wrap each match in ${...}
 227  * Return: number of matches found (in @cmdv)
 228  */
 229 int env_complete(char *var, int maxv, char *cmdv[], int maxsz, char *buf,
 230                  bool dollar_comp);
 231
 232 /**
 233  * eth_env_get_enetaddr() - Get an ethernet address from the environmnet
 234  *
 235  * @name: Environment variable to get (e.g. "ethaddr")
 236  * @enetaddr: Place to put MAC address (6 bytes)
 237  * Return: 1 if OK, 0 on error
 238  */
 239 int eth_env_get_enetaddr(const char *name, uint8_t *enetaddr);
 240
 241 /**
 242  * eth_env_set_enetaddr() - Set an ethernet address in the environmnet
 243  *
 244  * @name: Environment variable to set (e.g. "ethaddr")
 245  * @enetaddr: Pointer to MAC address to put into the variable (6 bytes)
 246  * Return: 0 if OK, non-zero otherwise
 247  */
 248 int eth_env_set_enetaddr(const char *name, const uint8_t *enetaddr);
 249
 250 /**
 251  * env_set_default_vars() - reset variables to their default value
 252  *
 253  * This resets individual variables to their value in the default environment
 254  *
 255  * @nvars: Number of variables to set/reset
 256  * @vars: List of variables to set/reset
 257  * @flags: Flags controlling matching (H_... - see search.h)
 258  */
 259 int env_set_default_vars(int nvars, char *const vars[], int flags);
 260
 261 /**
 262  * env_load() - Load the environment from storage
 263  *
 264  * Return: 0 if OK, -ve on error
 265  */
 266 int env_load(void);
 267
 268 /**
 269  * env_reload() - Re-Load the environment from current storage
 270  *
 271  * Return: 0 if OK, -ve on error
 272  */
 273 int env_reload(void);
 274
 275 /**
 276  * env_save() - Save the environment to storage
 277  *
 278  * Return: 0 if OK, -ve on error
 279  */
 280 int env_save(void);
 281
 282 /**
 283  * env_erase() - Erase the environment on storage
 284  *
 285  * Return: 0 if OK, -ve on error
 286  */
 287 int env_erase(void);
 288
 289 /**
 290  * env_select() - Select the environment storage
 291  *
 292  * Return: 0 if OK, -ve on error
 293  */
 294 int env_select(const char *name);
 295
 296 /**
 297  * env_import() - Import from a binary representation into hash table
 298  *
 299  * This imports the environment from a buffer. The format for each variable is
 300  * var=value\0 with a double \0 at the end of the buffer.
 301  *
 302  * @buf: Buffer containing the environment (struct environemnt_s *)
 303  * @check: non-zero to check the CRC at the start of the environment, 0 to
 304  *      ignore it
 305  * @flags: Flags controlling matching (H_... - see search.h)
 306  * Return: 0 if imported successfully, -ENOMSG if the CRC was bad, -EIO if
 307  *      something else went wrong
 308  */
 309 int env_import(const char *buf, int check, int flags);
 310
 311 /**
 312  * env_export() - Export the environment to a buffer
 313  *
 314  * Export from hash table into binary representation
 315  *
 316  * @env_out: Buffer to contain the environment (must be large enough!)
 317  * Return: 0 if OK, 1 on error
 318  */
 319 int env_export(struct environment_s *env_out);
 320
 321 /**
 322  * env_check_redund() - check the two redundant environments
 323  *   and find out, which is the valid one.
 324  *
 325  * @buf1: First environment (struct environemnt_s *)
 326  * @buf1_read_fail: 0 if buf1 is valid, non-zero if invalid
 327  * @buf2: Second environment (struct environemnt_s *)
 328  * @buf2_read_fail: 0 if buf2 is valid, non-zero if invalid
 329  * Return: 0 if OK,
 330  *      -EIO if no environment is valid,
 331  *      -ENOMSG if the CRC was bad
 332  */
 333
 334 int env_check_redund(const char *buf1, int buf1_read_fail,
 335                      const char *buf2, int buf2_read_fail);
 336
 337 /**
 338  * env_import_redund() - Select and import one of two redundant environments
 339  *
 340  * @buf1: First environment (struct environemnt_s *)
 341  * @buf1_read_fail: 0 if buf1 is valid, non-zero if invalid
 342  * @buf2: Second environment (struct environemnt_s *)
 343  * @buf2_read_fail: 0 if buf2 is valid, non-zero if invalid
 344  * @flags: Flags controlling matching (H_... - see search.h)
 345  * Return: 0 if OK, -EIO if no environment is valid, -ENOMSG if the CRC was bad
 346  */
 347 int env_import_redund(const char *buf1, int buf1_read_fail,
 348                       const char *buf2, int buf2_read_fail,
 349                       int flags);
 350
 351 /**
 352  * env_get_default() - Look up a variable from the default environment
 353  *
 354  * @name: Variable to look up
 355  * Return: value if found, NULL if not found in default environment
 356  */
 357 char *env_get_default(const char *name);
 358
 359 /**
 360  * env_get_default_into() - Look up a variable from the default environment and
 361  * copy its value in buf.
 362  *
 363  * @name: Variable to look up
 364  * Return: actual length of the variable value excluding the terminating
 365  *      NULL-byte, or -1 if the variable is not found
 366  */
 367 int env_get_default_into(const char *name, char *buf, unsigned int len);
 368
 369 /* [re]set to the default environment */
 370 void env_set_default(const char *s, int flags);
 371
 372 /**
 373  * env_import_fdt() - Import environment values from device tree blob
 374  *
 375  * This uses the value of the environment variable "env_fdt_path" as a
 376  * path to an fdt node, whose property/value pairs are added to the
 377  * environment.
 378  */
 379 #ifdef CONFIG_ENV_IMPORT_FDT
 380 void env_import_fdt(void);
 381 #else
 382 static inline void env_import_fdt(void) {}
 383 #endif
 384
 385 #endif