env: add check/apply logic to himport_r()
Change hashtable so that a callback function will decide whether a
variable can be overwritten, and possibly apply the changes.
So add a new field to struct hsearch_data:
o "apply" callback function to check whether a variable can be
overwritten, and possibly immediately apply the changes;
when NULL, no check is performed.
And a new argument to himport_r():
o "do_apply": whether to call the apply callback function
NOTE: This patch does not change the current behavior.
Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Reviewed-by: Marek Vasut <marex@denx.de>
diff --git a/include/search.h b/include/search.h
index 94d75fc..721c8ac 100644
--- a/include/search.h
+++ b/include/search.h
@@ -57,6 +57,16 @@
struct _ENTRY *table;
unsigned int size;
unsigned int filled;
+/*
+ * Callback function which will check whether the given change for variable
+ * "name" from "oldval" to "newval" may be applied or not, and possibly apply
+ * such change.
+ * When (flag & H_FORCE) is set, it shall not print out any error message and
+ * shall force overwriting of write-once variables.
+.* Must return 0 for approval, 1 for denial.
+ */
+ int (*apply)(const char *name, const char *oldval,
+ const char *newval, int flag);
};
/* Create a new hashing table which will at most contain NEL elements. */
@@ -97,10 +107,12 @@
/*
* nvars: length of vars array
* vars: array of strings (variable names) to import (nvars == 0 means all)
+ * do_apply: whether to call callback function to check the new argument,
+ * and possibly apply changes (false means accept everything)
*/
extern int himport_r(struct hsearch_data *__htab,
const char *__env, size_t __size, const char __sep,
- int __flag, int nvars, char * const vars[]);
+ int __flag, int nvars, char * const vars[], int do_apply);
/* Flags for himport_r() */
#define H_NOCLEAR (1 << 0) /* do not clear hash table before importing */