[U-Boot] [PATCH v3 1/6] env: unify logic to check and apply changes

Marek Vasut
2012-04-02T18:56:04Z

Dear Gerlando Falauto,

> 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.
>
> Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
> ---
> common/cmd_nvedit.c | 170
> ++++++++++++++++++++++++++++++++------------------- include/search.h |
> 3 +-
> 2 files changed, 109 insertions(+), 64 deletions(-)
>
> diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
> index 22f9821..e762e76 100644
> --- a/common/cmd_nvedit.c
> +++ b/common/cmd_nvedit.c
> @@ -197,32 +197,21 @@ static int do_env_grep(cmd_tbl_t *cmdtp, int flag,
> #endif
>
> /*
> - * Set a new environment variable,
> - * or replace or delete an existing one.
> + * Perform 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 instead.
> + * 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 _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)
> @@ -233,60 +222,76 @@ int _do_env_set(int flag, int argc, char * const
> argv[]) console = stderr;
>
> if (console != -1) {
> - if (argc < 3) { /* Cannot delete it! */
> - printf("Can't delete \"%s\"\n", name);
> + if ((newval == NULL) || (*newval == '\0')) {
> + /* We cannot delete stdin/stdout/stderr */
> + if ((flag & H_FORCE) == 0)

Given H_FORCE isn't set on any env var yet, won't this break bisectability?

> + 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 */
> }
>
> /*
> - * Some variables like "ethaddr" and "serial#" can be set only
> - * once and cannot be deleted; also, "ver" is readonly.
> + * Some variables like "ethaddr" and "serial#" can be set only 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])
> break;
> }
> if (i == N_BAUDRATES) {
> - printf("## Baudrate %d bps not supported\n",
> - baudrate);
> + if ((flag & H_FORCE) == 0)
> + printf("## Baudrate %d bps not "
> + "supported\n", 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);
> + "press ENTER ...\n", baudrate);

What changed above?

> udelay(50000);
> gd->baudrate = baudrate;
> #if defined(CONFIG_PPC) || defined(CONFIG_MCF52x2)
> @@ -300,6 +305,73 @@ 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(name, "loadaddr") == 0) {
> + load_addr = simple_strtoul(newval, NULL, 16);
> + return 0;
> + }
> +#if defined(CONFIG_CMD_NET)
> + else if (strcmp(name, "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 ? */

Shouldn't delete-only be handled before env_check_apply() to make it faster?

> if (argc < 3 || argv[2] == NULL) {
> int rc = hdelete_r(name, &env_htab);
> @@ -337,34 +409,6 @@ 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;
> }
>
> diff --git a/include/search.h b/include/search.h
> index ef53edb..a4a5ef4 100644
> --- a/include/search.h
> +++ b/include/search.h
> @@ -99,6 +99,7 @@ extern int himport_r(struct hsearch_data *__htab,
> int __flag);
>
> /* Flags for himport_r() */
> -#define H_NOCLEAR 1 /* do not clear hash table before
importing */
> +#define H_NOCLEAR (1 << 0) /* do not clear hash table before
importing */
> +#define H_FORCE (1 << 1) /* overwrite read-only/write-once
variables */
>
> #endif /* search.h */