env: make "env default" selective, check and apply

Change the syntax (user API) for "env default":
  -f: override write-once variables
  var... : accept individual variable(s)
  -a: all (resetting the whole env is NOT the default behavior)

Enable variable checking and make changes effective by
enabling do_apply argument to himport_r().

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>

diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c
index 310ca16ae303d2ea0aff03141d7df2b9b920316c..3474bc60940bb1b4d5ac7dc9324287627f3939b4 100644 (file)
--- a/common/cmd_nvedit.c
+++ b/common/cmd_nvedit.c
@@ -656,14 +656,41 @@ int envmatch(uchar *s1, int i2)
        return -1;
 }
 
-static int do_env_default(cmd_tbl_t *cmdtp, int flag,
+static int do_env_default(cmd_tbl_t *cmdtp, int __flag,
                          int argc, char * const argv[])
 {
-       if (argc != 2 || strcmp(argv[1], "-f") != 0)
-               return CMD_RET_USAGE;
+       int all = 0, flag = 0;
 
-       set_default_env("## Resetting to default environment\n");
-       return 0;
+       debug("Initial value for argc=%d\n", argc);
+       while (--argc > 0 && **++argv == '-') {
+               char *arg = *argv;
+
+               while (*++arg) {
+                       switch (*arg) {
+                       case 'a':               /* default all */
+                               all = 1;
+                               break;
+                       case 'f':               /* force */
+                               flag |= H_FORCE;
+                               break;
+                       default:
+                               return cmd_usage(cmdtp);
+                       }
+               }
+       }
+       debug("Final value for argc=%d\n", argc);
+       if (all && (argc == 0)) {
+               /* Reset the whole environment */
+               set_default_env("## Resetting to default environment\n");
+               return 0;
+       }
+       if (!all && (argc > 0)) {
+               /* Reset individual variables */
+               set_default_vars(argc, argv);
+               return 0;
+       }
+
+       return cmd_usage(cmdtp);
 }
 
 static int do_env_delete(cmd_tbl_t *cmdtp, int flag,
@@ -994,7 +1021,8 @@ U_BOOT_CMD(
 #if defined(CONFIG_CMD_ASKENV)
        "ask name [message] [size] - ask for environment variable\nenv "
 #endif
-       "default -f - reset default environment\n"
+       "default [-f] -a - [forcibly] reset default environment\n"
+       "env default [-f] var [...] - [forcibly] reset variable(s) to their default values\n"
 #if defined(CONFIG_CMD_EDITENV)
        "env edit name - edit environment variable\n"
 #endif

diff --git a/common/env_common.c b/common/env_common.c
index b9865bf630b2866246c08e71353710cd577ef546..3e46c260df815a2dfeb4d707c6e697cc0ce80347 100644 (file)
--- a/common/env_common.c
+++ b/common/env_common.c
@@ -180,6 +180,11 @@ const uchar *env_get_addr(int index)
 
 void set_default_env(const char *s)
 {
+       /*
+        * By default, do not apply changes as they will eventually
+        * be applied by someone else
+        */
+       int do_apply = 0;
        if (sizeof(default_environment) > ENV_SIZE) {
                puts("*** Error - default environment is too large\n\n");
                return;
@@ -191,6 +196,14 @@ void set_default_env(const char *s)
                                "using default environment\n\n",
                                s + 1);
                } else {
+                       /*
+                        * This set_to_default was explicitly asked for
+                        * by the user, as opposed to being a recovery
+                        * mechanism.  Therefore we check every single
+                        * variable and apply changes to the system
+                        * right away (e.g. baudrate, console).
+                        */
+                       do_apply = 1;
                        puts(s);
                }
        } else {
@@ -199,12 +212,25 @@ void set_default_env(const char *s)
 
        if (himport_r(&env_htab, (char *)default_environment,
                        sizeof(default_environment), '\0', 0,
-                       0, NULL, 0 /* do_apply */) == 0)
+                       0, NULL, do_apply) == 0)
                error("Environment import failed: errno = %d\n", errno);
 
        gd->flags |= GD_FLG_ENV_READY;
 }
 
+
+/* [re]set individual variables to their value in the default environment */
+int set_default_vars(int nvars, char * const vars[])
+{
+       /*
+        * Special use-case: import from default environment
+        * (and use \0 as a separator)
+        */
+       return himport_r(&env_htab, (const char *)default_environment,
+                               sizeof(default_environment), '\0', H_NOCLEAR,
+                               nvars, vars, 1 /* do_apply */);
+}
+
 /*
  * Check if CRC is valid and (if yes) import the environment.
  * Note that "buf" may or may not be aligned.

diff --git a/include/environment.h b/include/environment.h
index 90fb1302b1e6ffb077f8d1941b4f841804b6df23..e8ab7033bf7e75166d2e008985215da45146471d 100644 (file)
--- a/include/environment.h
+++ b/include/environment.h
@@ -181,6 +181,9 @@ void env_crc_update(void);
 /* [re]set to the default environment */
 void set_default_env(const char *s);
 
+/* [re]set individual variables to their value in the default environment */
+int set_default_vars(int nvars, char * const vars[]);
+
 /* Import from binary representation into hash table */
 int env_import(const char *buf, int check);