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authorJoe Hershberger <joe.hershberger@ni.com>2012-12-11 22:16:24 -0600
committerTom Rini <trini@ti.com>2012-12-13 11:46:55 -0700
commit170ab11075d3be56e89d6444abf1148329130f4b (patch)
treed3088ad532f4f4a0082f625ce50cfd120d6a6a1d /lib/hashtable.c
parentbe11235ab802844e12d84921a38fd8ae4ddda080 (diff)
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env: Add support for callbacks to environment vars
Add support for per-variable callbacks to the "hashtable" functions. Signed-off-by: Joe Hershberger <joe.hershberger@ni.com> !!!fix comment in callback
Diffstat (limited to 'lib/hashtable.c')
-rw-r--r--lib/hashtable.c67
1 files changed, 63 insertions, 4 deletions
diff --git a/lib/hashtable.c b/lib/hashtable.c
index 7c6b96c..e922666 100644
--- a/lib/hashtable.c
+++ b/lib/hashtable.c
@@ -54,7 +54,8 @@
#define CONFIG_ENV_MAX_ENTRIES 512
#endif
-#include "search.h"
+#include <env_callback.h>
+#include <search.h>
/*
* [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
@@ -274,6 +275,17 @@ static inline int _compare_and_overwrite_entry(ENTRY item, ACTION action,
return 0;
}
+ /* If there is a callback, call it */
+ if (htab->table[idx].entry.callback &&
+ htab->table[idx].entry.callback(item.key,
+ item.data, env_op_overwrite, flag)) {
+ debug("callback() rejected setting variable "
+ "%s, skipping it!\n", item.key);
+ __set_errno(EINVAL);
+ *retval = NULL;
+ return 0;
+ }
+
free(htab->table[idx].entry.data);
htab->table[idx].entry.data = strdup(item.data);
if (!htab->table[idx].entry.data) {
@@ -398,6 +410,9 @@ int hsearch_r(ENTRY item, ACTION action, ENTRY ** retval,
++htab->filled;
+ /* This is a new entry, so look up a possible callback */
+ env_callback_init(&htab->table[idx].entry);
+
/* check for permission */
if (htab->change_ok != NULL && htab->change_ok(
&htab->table[idx].entry, item.data, env_op_create, flag)) {
@@ -409,6 +424,18 @@ int hsearch_r(ENTRY item, ACTION action, ENTRY ** retval,
return 0;
}
+ /* If there is a callback, call it */
+ if (htab->table[idx].entry.callback &&
+ htab->table[idx].entry.callback(item.key, item.data,
+ env_op_create, flag)) {
+ debug("callback() rejected setting variable "
+ "%s, skipping it!\n", item.key);
+ _hdelete(item.key, htab, &htab->table[idx].entry, idx);
+ __set_errno(EINVAL);
+ *retval = NULL;
+ return 0;
+ }
+
/* return new entry */
*retval = &htab->table[idx].entry;
return 1;
@@ -437,6 +464,7 @@ static void _hdelete(const char *key, struct hsearch_data *htab, ENTRY *ep,
debug("hdelete: DELETING key \"%s\"\n", key);
free((void *)ep->key);
free(ep->data);
+ ep->callback = NULL;
htab->table[idx].used = -1;
--htab->filled;
@@ -466,6 +494,15 @@ int hdelete_r(const char *key, struct hsearch_data *htab, int flag)
return 0;
}
+ /* If there is a callback, call it */
+ if (htab->table[idx].entry.callback &&
+ htab->table[idx].entry.callback(key, NULL, env_op_delete, flag)) {
+ debug("callback() rejected deleting variable "
+ "%s, skipping it!\n", key);
+ __set_errno(EINVAL);
+ return 0;
+ }
+
_hdelete(key, htab, ep, idx);
return 1;
@@ -838,11 +875,9 @@ int himport_r(struct hsearch_data *htab,
e.data = value;
hsearch_r(e, ENTER, &rv, htab, flag);
- if (rv == NULL) {
+ if (rv == NULL)
printf("himport_r: can't insert \"%s=%s\" into hash table\n",
name, value);
- return 0;
- }
debug("INSERT: table %p, filled %d/%d rv %p ==> name=\"%s\" value=\"%s\"\n",
htab, htab->filled, htab->size,
@@ -873,3 +908,27 @@ int himport_r(struct hsearch_data *htab,
debug("INSERT: done\n");
return 1; /* everything OK */
}
+
+/*
+ * hwalk_r()
+ */
+
+/*
+ * Walk all of the entries in the hash, calling the callback for each one.
+ * this allows some generic operation to be performed on each element.
+ */
+int hwalk_r(struct hsearch_data *htab, int (*callback)(ENTRY *))
+{
+ int i;
+ int retval;
+
+ for (i = 1; i <= htab->size; ++i) {
+ if (htab->table[i].used > 0) {
+ retval = callback(&htab->table[i].entry);
+ if (retval)
+ return retval;
+ }
+ }
+
+ return 0;
+}