From: Andreas Fenkart afenkart@gmail.com

For double buffering to work, the target buffer must always be big enough to hold all data. This can only be ensured if buffers are of equal size, otherwise one must be smaller and we risk data loss when copying from the bigger to the smaller buffer.

Signed-off-by: Andreas Fenkart andreas.fenkart@digitalstrom.com --- tools/env/fw_env.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c index 692abda..b1c8217 100644 --- a/tools/env/fw_env.c +++ b/tools/env/fw_env.c @@ -1382,18 +1382,19 @@ static int parse_config(struct env_opts *opts) return -1; }

- if (HaveRedundEnv && stat (DEVNAME (1), &st)) { - fprintf (stderr, - "Cannot access MTD device %s: %s\n", - DEVNAME (1), strerror (errno)); - return -1; - } + if (HaveRedundEnv) { + if (stat(DEVNAME(1), &st)) { + fprintf(stderr, + "Cannot access MTD device %s: %s\n", + DEVNAME(1), strerror(errno)); + return -1; + }

- if (HaveRedundEnv && ENVSIZE(0) != ENVSIZE(1)) { - ENVSIZE(0) = ENVSIZE(1) = min(ENVSIZE(0), ENVSIZE(1)); - fprintf(stderr, - "Redundant environments have inequal size, set to 0x%08lx\n", - ENVSIZE(1)); + if (ENVSIZE(0) != ENVSIZE(1)) { + fprintf(stderr, + "Redundant environments have unequal size"); + return -1; + } }

usable_envsize = CUR_ENVSIZE - sizeof(uint32_t);

there are two groups of functions: - application ready tools: fw_setenv/fw_getenv/fw_parse_script these are used, when creating a single binary containing multiple tools (busybox like) - file access like: open/read/write/close above functions are implemented on top of these. applications can use those to modify several variables without creating a temporary batch script file

Signed-off-by: Andreas Fenkart andreas.fenkart@digitalstrom.com --- tools/env/fw_env.h | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 74 insertions(+), 1 deletion(-)

diff --git a/tools/env/fw_env.h b/tools/env/fw_env.h index dac964d..8bf74f3 100644 --- a/tools/env/fw_env.h +++ b/tools/env/fw_env.h @@ -67,12 +67,85 @@ struct env_opts {

int parse_aes_key(char *key, uint8_t *bin_key);

+/** + * fw_printenv - print one or several environment variables + * + * @argc number of variables names to be printed, print all if 0 + * @argv array of variable names to be printed + * @value_only do not repeat the variable name, only print the value, + * only one variable allowed with this option, argc must be 1 + * @opts encryption key, configuration file, defaults are used if NULL + */ int fw_printenv(int argc, char *argv[], int value_only, struct env_opts *opts); -char *fw_getenv(char *name); + +/** + * fw_setenv - adds or removes one variable from the environment + * + * @argc number of strings in argv, argv[0] is variable name, + * argc==1 means erase variable, argc > 1 means add a variable + * @argv argv[0] is variable name, argv[1..argc-1] are concatenated separated + * by single blank and set as the new value of the variable + * @opts how to retrieve environment from flash, defaults are used if NULL + * @ret EROFS if variable must not be changed (ethaddr, serial#) + */ int fw_setenv(int argc, char *argv[], struct env_opts *opts); + +/** + * fw_parse_script - add/remove multiple variables with a batch script + * + * @fname batch script file name + * @opts encryption key, configuration file, defaults are used if NULL + * + * Script Syntax: + * key [[space]+ value] + * lines starting with '#' treated as comment + * + * A variable without value will be deleted. Any number of spaces are allowed + * between key and value. The value starts with the first non-space character + * and ends with newline. No comments allowed on these lines. Spaces inside + * the value are preserved verbatim. + * + * Script Example:" + * netdev eth0 + * kernel_addr 400000 + * foo spaces are copied verbatim + * # delete variable bar + * bar\n" + */ int fw_parse_script(char *fname, struct env_opts *opts); + + +/** + * fw_env_open - read enviroment from flash and cache it in RAM + * + * @opts encryption key, configuration file, defaults are used if NULL + */ int fw_env_open(struct env_opts *opts); + +/** + * fw_getenv - lookup variable in RAM cache + * + * @name variable to be searched + * @ret NULL if not found + */ +char *fw_getenv(char *name); + +/** + * fw_env_write - set/clear a single variable in the RAM cache + * + * This is called in sequence to update the environment in RAM without updating + * the copy in flash after each set + * + * @name variable + * @value delete variable if NULL, otherwise create or overwrite the variable + */ int fw_env_write(char *name, char *value); + +/** + * fw_env_close - writes environment from RAM back to flash + * + * @opts encryption key, configuration file, defaults are used if NULL + */ int fw_env_close(struct env_opts *opts);

unsigned long crc32(unsigned long, const unsigned char *, unsigned);