Fiddling with llist to make memory management easier. Specifically, the

option to delete the contents of the list when we delete the list is a
good thing.

5 files changed, 27 insertions, 16 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 48239798b..39361a232 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -477,8 +477,8 @@ typedef struct llist_s {
 } llist_t;
 extern llist_t *llist_add_to(llist_t *old_head, char *new_item);
 extern llist_t *llist_add_to_end(llist_t *list_head, char *data);
-extern llist_t *llist_free_one(llist_t *elm);
-extern void llist_free(llist_t *elm);
+extern void *llist_pop(llist_t **elm);
+extern void llist_free(llist_t *elm, void (*freeit)(void *data));
 
 extern void print_login_issue(const char *issue_file, const char *tty);
 extern void print_login_prompt(void);
diff --git a/libbb/Makefile.in b/libbb/Makefile.in
index e7725b8f0..865b7e726 100644
--- a/libbb/Makefile.in
+++ b/libbb/Makefile.in
@@ -101,7 +101,7 @@ $(LIBBB_MOBJ5):$(LIBBB_MSRC5)
         $(compile.c) -DL_$(notdir $*)
 
 LIBBB_MSRC6:=$(srcdir)/llist.c
-LIBBB_MOBJ6:=llist_add_to.o llist_add_to_end.o llist_free_one.o llist_free.o
+LIBBB_MOBJ6:=llist_add_to.o llist_add_to_end.o llist_pop.o llist_free.o
 LIBBB_MOBJ6:=$(patsubst %,$(LIBBB_DIR)/%, $(LIBBB_MOBJ6))
 $(LIBBB_MOBJ6):$(LIBBB_MSRC6)
         $(compile.c) -DL_$(notdir $*)
diff --git a/libbb/llist.c b/libbb/llist.c
index 5b70d6628..0d599db6b 100644
--- a/libbb/llist.c
+++ b/libbb/llist.c
@@ -47,21 +47,32 @@ llist_t *llist_add_to_end(llist_t *list_head, char *data)
 }
 #endif
 
-#ifdef L_llist_free_one
-/* Free the current list element and advance to the next entry in the list.
- * Returns a pointer to the next element.  */
-llist_t *llist_free_one(llist_t *elm)
+#ifdef L_llist_pop
+/* Remove first element from the list and return it */
+void *llist_pop(llist_t **head)
 {
-        llist_t *next = elm ? elm->link : NULL;
-        free(elm);
-        return next;
+        void *data;
+
+        if(!*head) data = *head;
+        else {
+                void *next = (*head)->link;
+                data = (*head)->data;
+                *head = (*head)->link;
+                free(next);
+        }
+
+        return data;
 }
 #endif
 
 #ifdef L_llist_free
-/* Recursively free all elements in the linked list.  */
-void llist_free(llist_t *elm)
+/* Recursively free all elements in the linked list.  If freeit != NULL
+ * call it on each datum in the list */
+void llist_free(llist_t *elm, void (*freeit)(void *data))
 {
-        while ((elm = llist_free_one(elm)));
+        while (elm) {
+                void *data = llist_pop(&elm);
+                if (freeit) freeit(data);
+        }
 }
 #endif
diff --git a/procps/pidof.c b/procps/pidof.c
index 5b3e53fdf..98008aaf1 100644
--- a/procps/pidof.c
+++ b/procps/pidof.c
@@ -65,7 +65,7 @@ int pidof_main(int argc, char **argv)
                 while (omits_p) {
                         /* are we asked to exclude the parent's process ID?  */
                         if (!strncmp(omits_p->data, "%PPID", 5)) {
-                                omits_p = llist_free_one(omits_p);
+                                llist_pop(&omits_p);
                                 snprintf(getppid_str, sizeof(getppid_str), "%d", getppid());
                                 omits_p = llist_add_to(omits_p, getppid_str);
 #if 0
@@ -117,7 +117,7 @@ int pidof_main(int argc, char **argv)
 
 #if ENABLE_FEATURE_PIDOF_OMIT
         if (ENABLE_FEATURE_CLEAN_UP)
-                llist_free(omits);
+                llist_free(omits, NULL);
 #endif
         return fail ? EXIT_FAILURE : EXIT_SUCCESS;
 }
diff --git a/util-linux/mount.c b/util-linux/mount.c
index 61ceba829..4bd6433ca 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -182,7 +182,7 @@ llist_t *fslist = 0;
 #if ENABLE_FEATURE_CLEAN_UP
 static void delete_block_backed_filesystems(void)
 {
-        llist_free(fslist);
+        llist_free(fslist, free);
 }
 #else
 void delete_block_backed_filesystems(void);