env: Add support for access control to .flags

Add support for read-only, write-once, and change-default.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>

2 files changed, 50 insertions, 3 deletions

diff --git a/include/env_flags.h b/include/env_flags.h
index 7e72523..0bdae07 100644
--- a/include/env_flags.h
+++ b/include/env_flags.h
@@ -36,9 +36,18 @@ enum env_flags_vartype {
 	env_flags_vartype_end
 };
 
+enum env_flags_varaccess {
+	env_flags_varaccess_any,
+	env_flags_varaccess_readonly,
+	env_flags_varaccess_writeonce,
+	env_flags_varaccess_changedefault,
+	env_flags_varaccess_end
+};
+
 #define ENV_FLAGS_VAR ".flags"
 #define ENV_FLAGS_ATTR_MAX_LEN 2
 #define ENV_FLAGS_VARTYPE_LOC 0
+#define ENV_FLAGS_VARACCESS_LOC 1
 
 #ifndef CONFIG_ENV_FLAGS_LIST_STATIC
 #define CONFIG_ENV_FLAGS_LIST_STATIC ""
@@ -53,15 +62,31 @@ enum env_flags_vartype {
  */
 void env_flags_print_vartypes(void);
 /*
+ * Print the whole list of available access flags.
+ */
+void env_flags_print_varaccess(void);
+/*
  * Return the name of the type.
  */
 const char *env_flags_get_vartype_name(enum env_flags_vartype type);
+/*
+ * Return the name of the access.
+ */
+const char *env_flags_get_varaccess_name(enum env_flags_varaccess access);
 #endif
 
 /*
  * Parse the flags string from a .flags attribute list into the vartype enum.
  */
 enum env_flags_vartype env_flags_parse_vartype(const char *flags);
+/*
+ * Parse the flags string from a .flags attribute list into the varaccess enum.
+ */
+enum env_flags_varaccess env_flags_parse_varaccess(const char *flags);
+/*
+ * Parse the binary flags from a hash table entry into the varaccess enum.
+ */
+enum env_flags_varaccess env_flags_parse_varaccess_from_binflags(int binflags);
 
 #ifdef USE_HOSTCC
 /*
@@ -69,11 +94,25 @@ enum env_flags_vartype env_flags_parse_vartype(const char *flags);
  */
 enum env_flags_vartype env_flags_get_type(const char *name);
 /*
+ * Look up the access of a variable directly from the .flags var.
+ */
+enum env_flags_varaccess env_flags_get_access(const char *name);
+/*
  * Validate the newval for its type to conform with the requirements defined by
  * its flags (directly looked at the .flags var).
  */
 int env_flags_validate_type(const char *name, const char *newval);
 /*
+ * Validate the newval for its access to conform with the requirements defined
+ * by its flags (directly looked at the .flags var).
+ */
+int env_flags_validate_access(const char *name, int check_mask);
+/*
+ * Validate that the proposed access to variable "name" is valid according to
+ * the defined flags for that variable, if any.
+ */
+int env_flags_validate_varaccess(const char *name, int check_mask);
+/*
  * Validate the parameters passed to "env set" for type compliance
  */
 int env_flags_validate_env_set_params(int argc, char * const argv[]);
@@ -94,13 +133,18 @@ void env_flags_init(ENTRY *var_entry);
 int env_flags_validate(const ENTRY *item, const char *newval, enum env_op op,
 	int flag);
 
+#endif /* USE_HOSTCC */
+
 /*
  * These are the binary flags used in the environment entry->flags variable to
  * decribe properties of veriables in the table
  */
-#define ENV_FLAGS_VARTYPE_BIN_MASK	0x00000007
+#define ENV_FLAGS_VARTYPE_BIN_MASK			0x00000007
 /* The actual variable type values use the enum value (within the mask) */
-
-#endif /* USE_HOSTCC */
+#define ENV_FLAGS_VARACCESS_PREVENT_DELETE		0x00000008
+#define ENV_FLAGS_VARACCESS_PREVENT_CREATE		0x00000010
+#define ENV_FLAGS_VARACCESS_PREVENT_OVERWR		0x00000020
+#define ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR	0x00000040
+#define ENV_FLAGS_VARACCESS_BIN_MASK			0x00000078
 
 #endif /* __ENV_FLAGS_H__ */
diff --git a/include/environment.h b/include/environment.h
index 00e59ba..e64b43d 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -181,6 +181,9 @@ unsigned char env_get_char_memory(int index);
 /* Function that updates CRC of the enironment */
 void env_crc_update(void);
 
+/* Look up the variable from the default environment */
+char *getenv_default(const char *name);
+
 /* [re]set to the default environment */
 void set_default_env(const char *s);