[U-Boot] [PATCH v1 3/5] env: unify logic to check and apply changes
Simon Glass
sjg at chromium.org
Wed Dec 7 02:50:47 CET 2011
Hi,
On Fri, Nov 18, 2011 at 8:49 AM, Gerlando Falauto
<gerlando.falauto at keymile.com> wrote:
> The logic of checking special parameters (e.g. baudrate, stdin, stdout,
> for a valid value and/or whether can be overwritten) and applying the
> new value to the running system is now all within a single function
> env_check_apply() which can be called whenever changes are made
> to the environment, no matter if by set, default or import.
>
> With this patch env_check_apply() is only called by "env set",
> retaining previous behavior.
>
> Also allow for selectively importing/resetting variables.
>
> So add 3 new arguments to himport_r():
> o "nvars", "vars":, number and list of variables to take into account
> (0 means ALL)
>
> o "apply" callback function to check whether a variable can be
> overwritten, and possibly immediately apply the changes;
> when NULL, no check is performed.
>
> Signed-off-by: Gerlando Falauto <gerlando.falauto at keymile.com>
I haven't seen any comments on this series, but it seems good to me.
However it no longer applies - can you please rebase and resend?
Regards,
Simon
> ---
> common/cmd_nvedit.c | 163 +++++++++++++++++++++++++++++++-----------------
> common/env_common.c | 6 +-
> include/environment.h | 7 ++
> include/search.h | 17 +++++-
> lib/hashtable.c | 43 +++++++++++++-
> 5 files changed, 174 insertions(+), 62 deletions(-)
>
> diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
> index 7194ade..d6ea25d 100644
> --- a/common/cmd_nvedit.c
> +++ b/common/cmd_nvedit.c
> @@ -196,32 +196,23 @@ static int do_env_grep (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[
> #endif
>
> /*
> - * Set a new environment variable,
> - * or replace or delete an existing one.
> + * Performs consistency checking before setting, replacing,
> + * or deleting an environment variable, then (if successful)
> + * apply the changes to internals so to make them effective.
> + * Code for this function was taken out of _do_env_set(),
> + * which now calls it.
> + * Also called as a callback function by himport_r().
> + * Returns 0 in case of success, 1 in case of failure.
> + * When (flag & H_FORCE) is set, force overwriting of
> + * write-once variables.
> */
>
> -int _do_env_set (int flag, int argc, char * const argv[])
> +int env_check_apply(const char *name, const char *oldval,
> + const char *newval, int flag)
> {
> bd_t *bd = gd->bd;
> - int i, len;
> + int i;
> int console = -1;
> - char *name, *value, *s;
> - ENTRY e, *ep;
> -
> - name = argv[1];
> -
> - if (strchr(name, '=')) {
> - printf("## Error: illegal character '=' in variable name \"%s\"\n", name);
> - return 1;
> - }
> -
> - env_id++;
> - /*
> - * search if variable with this name already exists
> - */
> - e.key = name;
> - e.data = NULL;
> - hsearch_r(e, FIND, &ep, &env_htab);
>
> /* Check for console redirection */
> if (strcmp(name, "stdin") == 0)
> @@ -232,22 +223,23 @@ int _do_env_set (int flag, int argc, char * const argv[])
> console = stderr;
>
> if (console != -1) {
> - if (argc < 3) { /* Cannot delete it! */
> + if ((newval == NULL) || (*newval == '\0')) {
> + /* We cannot delete stdin/stdout/stderr */
> printf("Can't delete \"%s\"\n", name);
> return 1;
> }
>
> #ifdef CONFIG_CONSOLE_MUX
> - i = iomux_doenv(console, argv[2]);
> + i = iomux_doenv(console, newval);
> if (i)
> return i;
> #else
> /* Try assigning specified device */
> - if (console_assign(console, argv[2]) < 0)
> + if (console_assign(console, newval) < 0)
> return 1;
>
> #ifdef CONFIG_SERIAL_MULTI
> - if (serial_assign(argv[2]) < 0)
> + if (serial_assign(newval) < 0)
> return 1;
> #endif
> #endif /* CONFIG_CONSOLE_MUX */
> @@ -255,25 +247,35 @@ int _do_env_set (int flag, int argc, char * const argv[])
>
> /*
> * Some variables like "ethaddr" and "serial#" can be set only
> - * once and cannot be deleted; also, "ver" is readonly.
> + * once and cannot be deleted, unless CONFIG_ENV_OVERWRITE
> + * is defined.
> */
> - if (ep) { /* variable exists */
> #ifndef CONFIG_ENV_OVERWRITE
> + if (oldval != NULL && /* variable exists */
> + (flag & H_FORCE) == 0) { /* and we are not forced */
> if ((strcmp(name, "serial#") == 0) ||
> ((strcmp(name, "ethaddr") == 0)
> #if defined(CONFIG_OVERWRITE_ETHADDR_ONCE) && defined(CONFIG_ETHADDR)
> - && (strcmp(ep->data, MK_STR(CONFIG_ETHADDR)) != 0)
> + && (strcmp(oldval, MK_STR(CONFIG_ETHADDR)) != 0)
> #endif /* CONFIG_OVERWRITE_ETHADDR_ONCE && CONFIG_ETHADDR */
> ) ) {
> printf("Can't overwrite \"%s\"\n", name);
> return 1;
> }
> + }
> #endif
> + /*
> + * When we change baudrate, or we are doing an env default -a
> + * (which will erase all variables prior to calling this),
> + * we want the baudrate to actually change - for real.
> + */
> + if (oldval != NULL || /* variable exists */
> + (flag & H_NOCLEAR) == 0) { /* or env is clear */
> /*
> * Switch to new baudrate if new baudrate is supported
> */
> if (strcmp(name, "baudrate") == 0) {
> - int baudrate = simple_strtoul(argv[2], NULL, 10);
> + int baudrate = simple_strtoul(newval, NULL, 10);
> int i;
> for (i = 0; i < N_BAUDRATES; ++i) {
> if (baudrate == baudrate_table[i])
> @@ -284,6 +286,10 @@ int _do_env_set (int flag, int argc, char * const argv[])
> baudrate);
> return 1;
> }
> + if (gd->baudrate == baudrate) {
> + /* If unchanged, we just say it's OK */
> + return 0;
> + }
> printf ("## Switch baudrate to %d bps and press ENTER ...\n",
> baudrate);
> udelay(50000);
> @@ -301,6 +307,74 @@ int _do_env_set (int flag, int argc, char * const argv[])
> }
> }
>
> + /*
> + * Some variables should be updated when the corresponding
> + * entry in the environment is changed
> + */
> +
> + if (strcmp(name, "ipaddr") == 0) {
> + const char *s = newval;
> + char *e;
> + unsigned long addr;
> + bd->bi_ip_addr = 0;
> + for (addr = 0, i = 0; i < 4; ++i) {
> + ulong val = s ? simple_strtoul(s, &e, 10) : 0;
> + addr <<= 8;
> + addr |= (val & 0xFF);
> + if (s)
> + s = (*e) ? e+1 : e;
> + }
> + bd->bi_ip_addr = htonl(addr);
> + return 0;
> + } else if (strcmp(newval, "loadaddr") == 0) {
> + load_addr = simple_strtoul(newval, NULL, 16);
> + return 0;
> + }
> +#if defined(CONFIG_CMD_NET)
> + else if (strcmp(newval, "bootfile") == 0) {
> + copy_filename(BootFile, newval, sizeof(BootFile));
> + return 0;
> + }
> +#endif
> + return 0;
> +}
> +
> +/*
> + * Set a new environment variable,
> + * or replace or delete an existing one.
> +*/
> +int _do_env_set(int flag, int argc, char * const argv[])
> +{
> + int i, len;
> + char *name, *value, *s;
> + ENTRY e, *ep;
> +
> + name = argv[1];
> + value = argv[2];
> +
> + if (strchr(name, '=')) {
> + printf("## Error: illegal character '='"
> + "in variable name \"%s\"\n", name);
> + return 1;
> + }
> +
> + env_id++;
> + /*
> + * search if variable with this name already exists
> + */
> + e.key = name;
> + e.data = NULL;
> + hsearch_r(e, FIND, &ep, &env_htab);
> +
> + /*
> + * Perform requested checks. Notice how since we are overwriting
> + * a single variable, we need to set H_NOCLEAR
> + */
> + if (env_check_apply(name, ep ? ep->data : NULL, value, H_NOCLEAR)) {
> + debug("check function did not approve, refusing\n");
> + return 1;
> + }
> +
> /* Delete only ? */
> if ((argc < 3) || argv[2] == NULL) {
> int rc = hdelete_r(name, &env_htab);
> @@ -338,34 +412,6 @@ int _do_env_set (int flag, int argc, char * const argv[])
> return 1;
> }
>
> - /*
> - * Some variables should be updated when the corresponding
> - * entry in the environment is changed
> - */
> -
> - if (strcmp(name, "ipaddr") == 0) {
> - char *s = argv[2]; /* always use only one arg */
> - char *e;
> - unsigned long addr;
> - bd->bi_ip_addr = 0;
> - for (addr = 0, i = 0; i < 4; ++i) {
> - ulong val = s ? simple_strtoul(s, &e, 10) : 0;
> - addr <<= 8;
> - addr |= (val & 0xFF);
> - if (s) s = (*e) ? e+1 : e;
> - }
> - bd->bi_ip_addr = htonl(addr);
> - return 0;
> - } else if (strcmp(argv[1], "loadaddr") == 0) {
> - load_addr = simple_strtoul(argv[2], NULL, 16);
> - return 0;
> - }
> -#if defined(CONFIG_CMD_NET)
> - else if (strcmp(argv[1], "bootfile") == 0) {
> - copy_filename(BootFile, argv[2], sizeof(BootFile));
> - return 0;
> - }
> -#endif
> return 0;
> }
>
> @@ -888,7 +934,8 @@ static int do_env_import(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv
> addr = (char *)ep->data;
> }
>
> - if (himport_r(&env_htab, addr, size, sep, del ? 0 : H_NOCLEAR) == 0) {
> + if (himport_r(&env_htab, addr, size, sep, del ? 0 : H_NOCLEAR,
> + 0, NULL, NULL) == 0) {
> error("Environment import failed: errno = %d\n", errno);
> return 1;
> }
> diff --git a/common/env_common.c b/common/env_common.c
> index c7e9bea..9d8c59e 100644
> --- a/common/env_common.c
> +++ b/common/env_common.c
> @@ -190,7 +190,8 @@ void set_default_env(const char *s)
> }
>
> if (himport_r(&env_htab, (char *)default_environment,
> - sizeof(default_environment), '\0', 0) == 0) {
> + sizeof(default_environment), '\0', 0,
> + 0, NULL, NULL) == 0) {
> error("Environment import failed: errno = %d\n", errno);
> }
> gd->flags |= GD_FLG_ENV_READY;
> @@ -215,7 +216,8 @@ int env_import(const char *buf, int check)
> }
> }
>
> - if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0)) {
> + if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0,
> + 0, NULL, NULL)) {
> gd->flags |= GD_FLG_ENV_READY;
> return 1;
> }
> diff --git a/include/environment.h b/include/environment.h
> index 6394a96..1936411 100644
> --- a/include/environment.h
> +++ b/include/environment.h
> @@ -174,6 +174,13 @@ void set_default_env(const char *s);
> /* Import from binary representation into hash table */
> int env_import(const char *buf, int check);
>
> +/*
> + * Check if variable "name" can be changed from oldval to newval,
> + * and if so, apply the changes (e.g. baudrate)
> + */
> +int env_check_apply(const char *name, const char *oldval,
> + const char *newval, int flag);
> +
> #endif
>
> #endif /* _ENVIRONMENT_H_ */
> diff --git a/include/search.h b/include/search.h
> index ef53edb..2a59e03 100644
> --- a/include/search.h
> +++ b/include/search.h
> @@ -47,6 +47,13 @@ typedef struct entry {
> struct _ENTRY;
>
> /*
> + * Callback function to be called for checking whether the given change may
> + * be applied or not. Must return 0 for approval, 1 for denial.
> + */
> +typedef int (*apply_cb)(const char *name, const char *oldval,
> + const char *newval, int flag);
> +
> +/*
> * Family of hash table handling functions. The functions also
> * have reentrant counterparts ending with _r. The non-reentrant
> * functions all work on a signle internal hashing table.
> @@ -94,11 +101,19 @@ extern ssize_t hexport_r(struct hsearch_data *__htab,
> const char __sep, char **__resp, size_t __size,
> int argc, char * const argv[]);
>
> +/*
> + * nvars, vars: variables to import (nvars == 0 means all)
> + * apply_cb: callback function to check validity of the new argument,
> + * and possibly apply changes (NULL means accept everything)
> + */
> extern int himport_r(struct hsearch_data *__htab,
> const char *__env, size_t __size, const char __sep,
> - int __flag);
> + int __flag,
> + int nvars, char * const vars[],
> + apply_cb apply);
>
> /* Flags for himport_r() */
> #define H_NOCLEAR 1 /* do not clear hash table before importing */
> +#define H_FORCE 2 /* overwrite read-only/write-once variables */
>
> #endif /* search.h */
> diff --git a/lib/hashtable.c b/lib/hashtable.c
> index b7ba341..22421f9 100644
> --- a/lib/hashtable.c
> +++ b/lib/hashtable.c
> @@ -603,6 +603,22 @@ ssize_t hexport_r(struct hsearch_data *htab, const char sep,
> * himport()
> */
>
> +/* Check whether variable name is amongst vars[] */
> +static int process_var(const char *name, int nvars, char * const vars[])
> +{
> + int i = 0;
> + /* No variables specified means process all of them */
> + if (nvars == 0)
> + return 1;
> +
> + for (i = 0; i < nvars; i++) {
> + if (!strcmp(name, vars[i]))
> + return 1;
> + }
> + debug("Skipping non-listed variable %s\n", name);
> + return 0;
> +}
> +
> /*
> * Import linearized data into hash table.
> *
> @@ -639,7 +655,9 @@ ssize_t hexport_r(struct hsearch_data *htab, const char sep,
> */
>
> int himport_r(struct hsearch_data *htab,
> - const char *env, size_t size, const char sep, int flag)
> + const char *env, size_t size, const char sep, int flag,
> + int nvars, char * const vars[],
> + apply_cb apply)
> {
> char *data, *sp, *dp, *name, *value;
>
> @@ -726,6 +744,8 @@ int himport_r(struct hsearch_data *htab,
> *dp++ = '\0'; /* terminate name */
>
> debug("DELETE CANDIDATE: \"%s\"\n", name);
> + if (!process_var(name, nvars, vars))
> + continue;
>
> if (hdelete_r(name, htab) == 0)
> debug("DELETE ERROR ##############################\n");
> @@ -743,10 +763,31 @@ int himport_r(struct hsearch_data *htab,
> *sp++ = '\0'; /* terminate value */
> ++dp;
>
> + /* Skip variables which are not supposed to be treated */
> + if (!process_var(name, nvars, vars))
> + continue;
> +
> /* enter into hash table */
> e.key = name;
> e.data = value;
>
> + /* if there is an apply function, check what it has to say */
> + if (apply != NULL) {
> + debug("searching before calling cb function"
> + " for %s\n", name);
> + /*
> + * Search for variable in existing env, so to pass
> + * its previous value to the apply callback
> + */
> + hsearch_r(e, FIND, &rv, htab);
> + debug("previous value was %s\n", rv ? rv->data : "");
> + if (apply(name, rv ? rv->data : NULL, value, flag)) {
> + debug("callback function refused to set"
> + " variable %s, skipping it!\n", name);
> + continue;
> + }
> + }
> +
> hsearch_r(e, ENTER, &rv, htab);
> if (rv == NULL) {
> printf("himport_r: can't insert \"%s=%s\" into hash table\n",
> --
> 1.7.1
>
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