376 lines
18 KiB
C
376 lines
18 KiB
C
#ifndef _SYSPARAM_H_
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#define _SYSPARAM_H_
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#include <esp/types.h>
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/** @file sysparam.h
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*
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* Read/write "system parameters" to persistent flash.
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*
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* System parameters are stored as key/value pairs. Keys are string values
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* between 1 and 255 characters long. Values can be any data up to 255 bytes
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* in length (but are most commonly also text strings). Up to 126 key/value
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* pairs can be stored at a time.
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*
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* Keys and values are stored in flash using a progressive list structure
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* which allows space-efficient storage and minimizes flash erase cycles,
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* improving write speed and increasing the lifespan of the flash memory.
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*/
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#ifndef SYSPARAM_REGION_SECTORS
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/** Number of (4K) sectors that make up a sysparam region. Total sysparam data
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* cannot be larger than this. Note that the full sysparam area is two
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* regions, so the actual amount of used flash space will be *twice* this
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* amount.
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*/
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#define SYSPARAM_REGION_SECTORS 1
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#endif
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/** Status codes returned by all sysparam functions
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*
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* Error codes (`SYSPARAM_ERR_*`) all have values less than zero, and can be
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* returned by any function. Values greater than zero are non-error status
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* codes which may be returned by some functions to indicate various results.
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*/
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typedef enum {
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SYSPARAM_OK = 0, ///< Success
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SYSPARAM_NOTFOUND = 1, ///< Entry not found matching criteria
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SYSPARAM_PARSEFAILED = 2, ///< Unable to parse retrieved value
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SYSPARAM_ERR_NOINIT = -1, ///< sysparam_init() must be called first
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SYSPARAM_ERR_BADVALUE = -2, ///< One or more arguments were invalid
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SYSPARAM_ERR_FULL = -3, ///< No space left in sysparam area (or too many keys in use)
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SYSPARAM_ERR_IO = -4, ///< I/O error reading/writing flash
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SYSPARAM_ERR_CORRUPT = -5, ///< Sysparam region has bad/corrupted data
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SYSPARAM_ERR_NOMEM = -6, ///< Unable to allocate memory
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} sysparam_status_t;
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/** Structure used by sysparam_iter_next() to keep track of its current state
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* and return its results. This should be initialized by calling
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* sysparam_iter_start() and cleaned up afterward by calling
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* sysparam_iter_end().
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*/
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typedef struct {
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char *key;
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uint8_t *value;
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size_t key_len;
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size_t value_len;
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size_t bufsize;
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struct sysparam_context *ctx;
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} sysparam_iter_t;
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/** Initialize sysparam and set up the current area of flash to use.
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*
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* This must be called (and return successfully) before any other sysparam
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* routines (except sysparam_create_area()) are called.
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*
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* This should normally be taken care of automatically on boot by the OS
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* startup routines. It may be necessary to call it specially, however, if
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* the normal initialization failed, or after calling sysparam_create_area()
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* to reformat the current area.
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*
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* @param[in] base_addr The flash address which should contain the start of
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* the (already present) sysparam area
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*
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* @retval ::SYSPARAM_OK Initialization successful.
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* @retval ::SYSPARAM_NOTFOUND The specified address does not appear to
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* contain a sysparam area. It may be
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* necessary to call sysparam_create_area() to
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* create one first.
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_init(uint32_t base_addr);
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/** Create a new sysparam area in flash at the specified address.
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*
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* By default, this routine will scan the specified area to make sure it
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* appears to be empty (i.e. all 0xFF bytes) before setting it up as a new
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* sysparam area. If there appears to be other data already present, it will
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* not overwrite it. Setting `force` to `true` will cause it to clobber any
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* existing data instead.
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*
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* @param[in] base_addr The flash address at which it should start
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* (must be a multiple of the sector size)
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* @param[in] force Proceed even if the space does not appear to be empty
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*
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* @retval ::SYSPARAM_OK Area (re)created successfully.
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* @retval ::SYSPARAM_NOTFOUND `force` was not specified, and the area at
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* `base_addr` appears to have other data. No
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* action taken.
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*
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* Note: This routine can create a sysparam area in another location than the
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* one currently being used, but does not change which area is currently used
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* (you will need to call sysparam_init() again if you want to do that). If
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* you reformat the area currently being used, you will also need to call
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* sysparam_init() again afterward before you will be able to continue using
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* it.
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*/
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sysparam_status_t sysparam_create_area(uint32_t base_addr, bool force);
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/** Get the value associated with a key
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*
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* This is the core "get value" function. It will retrieve the value for the
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* specified key in a freshly malloc()'d buffer and return it. Raw values can
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* contain any data (including zero bytes), so the `actual_length` parameter
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* should be used to determine the length of the data in the buffer.
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*
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* It is up to the caller to free() the returned buffer when done using it.
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*
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* Note: If the status result is anything other than ::SYSPARAM_OK, the value
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* in `destptr` is not changed. This means it is possible to set a default
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* value before calling this function which will be left as-is if a sysparam
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* value could not be successfully read.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[out] destptr Pointer to a location to hold the address of the
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* returned data buffer
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* @param[out] actual_length Pointer to a location to hold the length of the
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* returned data buffer
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*
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* @retval ::SYSPARAM_OK Value successfully retrieved.
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* @retval ::SYSPARAM_NOTFOUND Key/value not found. No buffer returned.
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* @retval ::SYSPARAM_ERR_NOINIT sysparam_init() must be called first
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_get_data(const char *key, uint8_t **destptr, size_t *actual_length);
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/** Get the value associate with a key (static buffers only)
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*
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* This performs the same function as sysparam_get_data() but without
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* performing any memory allocations. It can thus be used before the heap has
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* been configured or in other cases where using the heap would be a problem
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* (i.e. in an OOM handler, etc). It requires that the caller pass in a
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* suitably sized buffer for the value to be read (if the supplied buffer is
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* not large enough, the returned value will be truncated and the full
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* required length will be returned in `actual_length`).
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*
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* NOTE: In addition to being large enough for the value, the supplied buffer
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* must also be at least as large as the length of the key being requested.
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* If it is not, an error will be returned.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[in] buffer Pointer to a buffer to hold the returned value
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* @param[in] buffer_size Length of the supplied buffer in bytes
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* @param[out] actual_length pointer to a location to hold the actual length
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* of the data which was associated with the key
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* (may be NULL).
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*
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* @retval ::SYSPARAM_OK Value successfully retrieved
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* @retval ::SYSPARAM_NOTFOUND Key/value not found
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* @retval ::SYSPARAM_ERR_NOINIT sysparam_init() must be called first
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* @retval ::SYSPARAM_ERR_NOMEM The supplied buffer is too small
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_get_data_static(const char *key, uint8_t *buffer, size_t buffer_size, size_t *actual_length);
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/** Get the string value associated with a key
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*
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* This routine can be used if you know that the value in a key will (or at
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* least should) be a string. It will return a zero-terminated char buffer
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* containing the value retrieved.
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*
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* It is up to the caller to free() the returned buffer when done using it.
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*
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* Note: If the status result is anything other than ::SYSPARAM_OK, the value
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* in `destptr` is not changed. This means it is possible to set a default
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* value before calling this function which will be left as-is if a sysparam
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* value could not be successfully read.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[out] destptr Pointer to a location to hold the address of the
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* returned data buffer
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*
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* @retval ::SYSPARAM_OK Value successfully retrieved.
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* @retval ::SYSPARAM_NOTFOUND Key/value not found.
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* @retval ::SYSPARAM_ERR_NOINIT sysparam_init() must be called first
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_get_string(const char *key, char **destptr);
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/** Get the int32_t value associated with a key
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*
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* This routine can be used if you know that the value in a key will (or at
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* least should) be an integer value. It will parse the stored data as a
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* number (in standard decimal or "0x" hex notation) and return the result.
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*
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* Note: If the status result is anything other than ::SYSPARAM_OK, the value
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* in `result` is not changed. This means it is possible to set a default
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* value before calling this function which will be left as-is if a sysparam
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* value could not be successfully read.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[out] result Pointer to a location to hold returned integer value
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*
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* @retval ::SYSPARAM_OK Value successfully retrieved.
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* @retval ::SYSPARAM_NOTFOUND Key/value not found.
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* @retval ::SYSPARAM_PARSEFAILED The retrieved value could not be parsed as
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* an integer.
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* @retval ::SYSPARAM_ERR_NOINIT sysparam_init() must be called first
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_get_int(const char *key, int32_t *result);
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/** Get the boolean value associated with a key
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*
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* This routine can be used if you know that the value in a key will (or at
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* least should) be a boolean setting. It will read the specified value as a
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* text string and attempt to parse it as a boolean value.
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*
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* It will recognize the following (case-insensitive) strings:
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* * True: "yes", "y", "true", "t", "1"
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* * False: "no", "n", "false", "f", "0"
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*
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* Note: If the status result is anything other than ::SYSPARAM_OK, the value
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* in `result` is not changed. This means it is possible to set a default
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* value before calling this function which will be left as-is if a sysparam
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* value could not be successfully read.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[out] result Pointer to a location to hold returned boolean value
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*
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* @retval ::SYSPARAM_OK Value successfully retrieved.
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* @retval ::SYSPARAM_NOTFOUND Key/value not found.
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* @retval ::SYSPARAM_PARSEFAILED The retrieved value could not be parsed as a
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* boolean setting.
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* @retval ::SYSPARAM_ERR_NOINIT sysparam_init() must be called first
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_get_bool(const char *key, bool *result);
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/** Set the value associated with a key
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*
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* The supplied value can be any data, up to 255 bytes in length. If `value`
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* is NULL or `value_len` is 0, this is treated as a request to delete any
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* current entry matching `key`.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[in] value Pointer to a buffer containing the value data
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* @param[in] value_len Length of the data in the buffer
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*
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* @retval ::SYSPARAM_OK Value successfully set.
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* @retval ::SYSPARAM_ERR_NOINIT sysparam_init() must be called first
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* @retval ::SYSPARAM_ERR_BADVALUE Either an empty key was provided or
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* value_len is too large
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* @retval ::SYSPARAM_ERR_FULL No space left in sysparam area
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* (or too many keys in use)
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_set_data(const char *key, const uint8_t *value, size_t value_len);
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/** Set a key's value from a string
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*
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* Performs the same function as sysparam_set_data(), but accepts a
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* zero-terminated string value instead.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[in] value Value to set (zero-terminated string)
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*
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* @retval ::SYSPARAM_OK Value successfully set.
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* @retval ::SYSPARAM_ERR_BADVALUE Either an empty key was provided or the
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* length of `value` is too large
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* @retval ::SYSPARAM_ERR_FULL No space left in sysparam area
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* (or too many keys in use)
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_set_string(const char *key, const char *value);
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/** Set a key's value as a number
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*
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* Converts an int32_t value to a decimal number and writes it to the
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* specified key. This does the inverse of the sysparam_get_int()
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* function.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[in] value Value to set
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*
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* @retval ::SYSPARAM_OK Value successfully set.
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* @retval ::SYSPARAM_ERR_BADVALUE An empty key was provided.
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* @retval ::SYSPARAM_ERR_FULL No space left in sysparam area
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* (or too many keys in use)
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_set_int(const char *key, int32_t value);
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/** Set a key's value as a boolean (yes/no) string
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*
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* Converts a bool value to a corresponding text string and writes it to the
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* specified key. This does the inverse of the sysparam_get_bool()
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* function.
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*
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* Note that if the key already contains a value which parses to the same
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* boolean (true/false) value, it is left unchanged.
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*
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* @param[in] key Key name (zero-terminated string)
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* @param[in] value Value to set
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*
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* @retval ::SYSPARAM_OK Value successfully set.
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* @retval ::SYSPARAM_ERR_BADVALUE An empty key was provided.
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* @retval ::SYSPARAM_ERR_FULL No space left in sysparam area
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* (or too many keys in use)
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_set_bool(const char *key, bool value);
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/** Begin iterating through all key/value pairs
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*
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* This function initializes a sysparam_iter_t structure to prepare it for
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* iterating through the list of key/value pairs using sysparam_iter_next().
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* This does not fetch any items (the first successive call to
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* sysparam_iter_next() will return the first key/value in the list).
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*
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* NOTE: When done, you must call sysparam_iter_end() to free the resources
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* associated with `iter`, or you will leak memory.
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*
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* @param[in] iter A pointer to a sysparam_iter_t structure to initialize
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*
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* @retval ::SYSPARAM_OK Initialization successful
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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*/
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sysparam_status_t sysparam_iter_start(sysparam_iter_t *iter);
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/** Fetch the next key/value pair
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*
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* This will retrieve the next key and value from the sysparam area, placing
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* them in `iter->key`, and `iter->value` (and updating `iter->key_len` and
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* `iter->value_len`).
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*
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* NOTE: `iter->key` and `iter->value` are static buffers local to the `iter`
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* structure, and will be overwritten with the next call to
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* sysparam_iter_next() using the same `iter`. They should *not* be free()d
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* after use.
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*
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* @param[in] iter The iterator structure to update
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*
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* @retval ::SYSPARAM_OK Next key/value retrieved
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* @retval ::SYSPARAM_ERR_NOMEM Unable to allocate memory
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* @retval ::SYSPARAM_ERR_CORRUPT Sysparam region has bad/corrupted data
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* @retval ::SYSPARAM_ERR_IO I/O error reading/writing flash
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*/
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sysparam_status_t sysparam_iter_next(sysparam_iter_t *iter);
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/** Finish iterating through keys/values
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*
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* Cleans up and releases resources allocated by sysparam_iter_start() /
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* sysparam_iter_next().
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*/
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void sysparam_iter_end(sysparam_iter_t *iter);
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#endif /* _SYSPARAM_H_ */
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