X-Git-Url: http://git.archive.openwrt.org/?p=project%2Fuci.git;a=blobdiff_plain;f=list.c;h=006e2a0ca8d2741f84731c62fc80eecebf877ef9;hp=502f51f216cd3debaa9e83eb1a8969af71247491;hb=ec8cbbbe0f20e67cbd3bd471b9ac55ceacaef7b8;hpb=f2520c27cd7942dc01d3386b4083b128648343c0

diff --git a/list.c b/list.c
index 502f51f..006e2a0 100644
--- a/list.c
+++ b/list.c
@@ -9,52 +9,35 @@
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
+ * GNU Lesser General Public License for more details.
  */
 
-#include <glob.h>
-
-/* initialize a list head/item */
-static inline void uci_list_init(struct uci_list *ptr)
+static void uci_list_set_pos(struct uci_list *head, struct uci_list *ptr, int pos)
 {
-	ptr->prev = ptr;
-	ptr->next = ptr;
-}
+	struct uci_list *new_head = head;
+	struct uci_element *p = NULL;
+
+	uci_list_del(ptr);
+	uci_foreach_element(head, p) {
+		if (pos-- <= 0)
+			break;
+		new_head = &p->list;
+	}
 
-/* inserts a new list entry after a given entry */
-static inline void uci_list_insert(struct uci_list *list, struct uci_list *ptr)
-{
-	list->next->prev = ptr;
-	ptr->prev = list;
-	ptr->next = list->next;
-	list->next = ptr;
+	uci_list_add(new_head->next, ptr);
 }
 
-/* inserts a new list entry at the tail of the list */
-static inline void uci_list_add(struct uci_list *head, struct uci_list *ptr)
+static inline void uci_list_fixup(struct uci_list *ptr)
 {
-	/* NB: head->prev points at the tail */
-	uci_list_insert(head->prev, ptr);
-}
-
-static inline void uci_list_del(struct uci_list *ptr)
-{
-	struct uci_list *next, *prev;
-
-	next = ptr->next;
-	prev = ptr->prev;
-
-	prev->next = next;
-	next->prev = prev;
-
-	uci_list_init(ptr);
+	ptr->prev->next = ptr;
+	ptr->next->prev = ptr;
 }
 
 /* 
  * uci_alloc_generic allocates a new uci_element with payload
  * payload is appended to the struct to save memory and reduce fragmentation
  */
-static struct uci_element *
+__private struct uci_element *
 uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size)
 {
 	struct uci_element *e;
@@ -74,13 +57,13 @@ uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size)
 
 error:
 	free(ptr);
-	UCI_THROW(ctx, ctx->errno);
+	UCI_THROW(ctx, ctx->err);
 
 done:
 	return e;
 }
 
-static void
+__private void
 uci_free_element(struct uci_element *e)
 {
 	if (e->name)
@@ -98,9 +81,10 @@ uci_alloc_option(struct uci_section *s, const char *name, const char *value)
 	struct uci_option *o;
 
 	o = uci_alloc_element(ctx, option, name, strlen(value) + 1);
-	o->value = uci_dataptr(o);
+	o->type = UCI_TYPE_STRING;
+	o->v.string = uci_dataptr(o);
 	o->section = s;
-	strcpy(o->value, value);
+	strcpy(o->v.string, value);
 	uci_list_add(&s->options, &o->e.list);
 
 	return o;
@@ -109,12 +93,93 @@ uci_alloc_option(struct uci_section *s, const char *name, const char *value)
 static inline void
 uci_free_option(struct uci_option *o)
 {
-	if ((o->value != uci_dataptr(o)) &&
-		(o->value != NULL))
-		free(o->value);
+	struct uci_element *e, *tmp;
+
+	switch(o->type) {
+	case UCI_TYPE_STRING:
+		if ((o->v.string != uci_dataptr(o)) &&
+			(o->v.string != NULL))
+			free(o->v.string);
+		break;
+	case UCI_TYPE_LIST:
+		uci_foreach_element_safe(&o->v.list, tmp, e) {
+			uci_free_element(e);
+		}
+		break;
+	default:
+		break;
+	}
 	uci_free_element(&o->e);
 }
 
+static struct uci_option *
+uci_alloc_list(struct uci_section *s, const char *name)
+{
+	struct uci_package *p = s->package;
+	struct uci_context *ctx = p->ctx;
+	struct uci_option *o;
+
+	o = uci_alloc_element(ctx, option, name, 0);
+	o->type = UCI_TYPE_LIST;
+	o->section = s;
+	uci_list_init(&o->v.list);
+	uci_list_add(&s->options, &o->e.list);
+
+	return o;
+}
+
+/* Based on an efficient hash function published by D. J. Bernstein */
+static unsigned int djbhash(unsigned int hash, char *str)
+{
+	int len = strlen(str);
+	int i;
+
+	/* initial value */
+	if (hash == ~0)
+		hash = 5381;
+
+	for(i = 0; i < len; i++) {
+		hash = ((hash << 5) + hash) + str[i];
+	}
+	return (hash & 0x7FFFFFFF);
+}
+
+/* fix up an unnamed section, e.g. after adding options to it */
+__private void uci_fixup_section(struct uci_context *ctx, struct uci_section *s)
+{
+	unsigned int hash = ~0;
+	struct uci_element *e;
+	char buf[16];
+
+	if (!s || s->e.name)
+		return;
+
+	/*
+	 * Generate a name for unnamed sections. This is used as reference
+	 * when locating or updating the section from apps/scripts.
+	 * To make multiple concurrent versions somewhat safe for updating,
+	 * the name is generated from a hash of its type and name/value
+	 * pairs of its option, and it is prefixed by a counter value.
+	 * If the order of the unnamed sections changes for some reason,
+	 * updates to them will be rejected.
+	 */
+	hash = djbhash(hash, s->type);
+	uci_foreach_element(&s->options, e) {
+		struct uci_option *o;
+		hash = djbhash(hash, e->name);
+		o = uci_to_option(e);
+		switch(o->type) {
+		case UCI_TYPE_STRING:
+			hash = djbhash(hash, o->v.string);
+			break;
+		default:
+			break;
+		}
+	}
+	sprintf(buf, "cfg%02x%04x", ++s->package->n_section, hash % (1 << 16));
+	s->e.name = uci_strdup(ctx, buf);
+}
+
 static struct uci_section *
 uci_alloc_section(struct uci_package *p, const char *type, const char *name)
 {
@@ -131,6 +196,7 @@ uci_alloc_section(struct uci_package *p, const char *type, const char *name)
 	strcpy(s->type, type);
 	if (name == NULL)
 		s->anonymous = true;
+	p->n_section++;
 
 	uci_list_add(&p->sections, &s->e.list);
 
@@ -151,45 +217,7 @@ uci_free_section(struct uci_section *s)
 	uci_free_element(&s->e);
 }
 
-/* record a change that was done to a package */
-static void
-uci_add_history(struct uci_context *ctx, struct uci_package *p, int cmd, char *section, char *option, char *value)
-{
-	struct uci_history *h;
-	int size = strlen(section) + 1;
-	char *ptr;
-
-	if (!p->confdir)
-		return;
-
-	if (value)
-		size += strlen(section) + 1;
-
-	h = uci_alloc_element(ctx, history, option, size);
-	ptr = uci_dataptr(h);
-	h->cmd = cmd;
-	h->section = strcpy(ptr, section);
-	if (value) {
-		ptr += strlen(ptr) + 1;
-		h->value = strcpy(ptr, value);
-	}
-	uci_list_add(&p->history, &h->e.list);
-}
-
-static void
-uci_free_history(struct uci_history *h)
-{
-	if (!h)
-		return;
-	if ((h->section != NULL) &&
-		(h->section != uci_dataptr(h))) {
-		free(h->section);
-		free(h->value);
-	}
-	uci_free_element(&h->e);
-}
-
-static struct uci_package *
+__plugin struct uci_package *
 uci_alloc_package(struct uci_context *ctx, const char *name)
 {
 	struct uci_package *p;
@@ -197,11 +225,12 @@ uci_alloc_package(struct uci_context *ctx, const char *name)
 	p = uci_alloc_element(ctx, package, name, 0);
 	p->ctx = ctx;
 	uci_list_init(&p->sections);
-	uci_list_init(&p->history);
+	uci_list_init(&p->delta);
+	uci_list_init(&p->saved_delta);
 	return p;
 }
 
-static void
+__private void
 uci_free_package(struct uci_package **package)
 {
 	struct uci_element *e, *tmp;
@@ -215,14 +244,34 @@ uci_free_package(struct uci_package **package)
 	uci_foreach_element_safe(&p->sections, tmp, e) {
 		uci_free_section(uci_to_section(e));
 	}
-	uci_foreach_element_safe(&p->history, tmp, e) {
-		uci_free_history(uci_to_history(e));
+	uci_foreach_element_safe(&p->delta, tmp, e) {
+		uci_free_delta(uci_to_delta(e));
+	}
+	uci_foreach_element_safe(&p->saved_delta, tmp, e) {
+		uci_free_delta(uci_to_delta(e));
 	}
 	uci_free_element(&p->e);
 	*package = NULL;
 }
 
-static struct uci_element *uci_lookup_list(struct uci_context *ctx, struct uci_list *list, const char *name)
+static void
+uci_free_any(struct uci_element **e)
+{
+	switch((*e)->type) {
+	case UCI_TYPE_SECTION:
+		uci_free_section(uci_to_section(*e));
+		break;
+	case UCI_TYPE_OPTION:
+		uci_free_option(uci_to_option(*e));
+		break;
+	default:
+		break;
+	}
+	*e = NULL;
+}
+
+__private struct uci_element *
+uci_lookup_list(struct uci_list *list, const char *name)
 {
 	struct uci_element *e;
 
@@ -233,28 +282,157 @@ static struct uci_element *uci_lookup_list(struct uci_context *ctx, struct uci_l
 	return NULL;
 }
 
-int uci_lookup(struct uci_context *ctx, struct uci_element **res, struct uci_package *p, char *section, char *option)
+static struct uci_element *
+uci_lookup_ext_section(struct uci_context *ctx, struct uci_ptr *ptr)
 {
-	struct uci_element *e;
+	char *idxstr, *t, *section, *name;
+	struct uci_element *e = NULL;
 	struct uci_section *s;
+	int idx, c;
+
+	section = uci_strdup(ctx, ptr->section);
+	name = idxstr = section + 1;
+
+	if (section[0] != '@')
+		goto error;
+
+	/* parse the section index part */
+	idxstr = strchr(idxstr, '[');
+	if (!idxstr)
+		goto error;
+	*idxstr = 0;
+	idxstr++;
+
+	t = strchr(idxstr, ']');
+	if (!t)
+		goto error;
+	if (t[1] != 0)
+		goto error;
+	*t = 0;
+
+	t = NULL;
+	idx = strtol(idxstr, &t, 10);
+	if (t && *t)
+		goto error;
+
+	if (!*name)
+		name = NULL;
+	else if (!uci_validate_type(name))
+		goto error;
+
+	/* if the given index is negative, it specifies the section number from 
+	 * the end of the list */
+	if (idx < 0) {
+		c = 0;
+		uci_foreach_element(&ptr->p->sections, e) {
+			s = uci_to_section(e);
+			if (name && (strcmp(s->type, name) != 0))
+				continue;
+
+			c++;
+		}
+		idx += c;
+	}
+
+	c = 0;
+	uci_foreach_element(&ptr->p->sections, e) {
+		s = uci_to_section(e);
+		if (name && (strcmp(s->type, name) != 0))
+			continue;
+
+		if (idx == c)
+			goto done;
+		c++;
+	}
+	e = NULL;
+	goto done;
+
+error:
+	e = NULL;
+	memset(ptr, 0, sizeof(struct uci_ptr));
+	UCI_THROW(ctx, UCI_ERR_INVAL);
+done:
+	free(section);
+	if (e)
+		ptr->section = e->name;
+	return e;
+}
 
+int
+uci_lookup_next(struct uci_context *ctx, struct uci_element **e, struct uci_list *list, const char *name)
+{
 	UCI_HANDLE_ERR(ctx);
-	UCI_ASSERT(ctx, res != NULL);
-	UCI_ASSERT(ctx, p != NULL);
-	UCI_ASSERT(ctx, uci_validate_name(section));
-	if (option)
-		UCI_ASSERT(ctx, uci_validate_name(option));
 
-	e = uci_lookup_list(ctx, &p->sections, section);
+	*e = uci_lookup_list(list, name);
+	if (!*e)
+		UCI_THROW(ctx, UCI_ERR_NOTFOUND);
+
+	return 0;
+}
+
+int
+uci_lookup_ptr(struct uci_context *ctx, struct uci_ptr *ptr, char *str, bool extended)
+{
+	struct uci_element *e;
+
+	UCI_HANDLE_ERR(ctx);
+	UCI_ASSERT(ctx, ptr != NULL);
+
+	if (str)
+		UCI_INTERNAL(uci_parse_ptr, ctx, ptr, str);
+
+	ptr->flags |= UCI_LOOKUP_DONE;
+
+	/* look up the package first */
+	if (ptr->p)
+		e = &ptr->p->e;
+	else
+		e = uci_lookup_list(&ctx->root, ptr->package);
+
+	if (!e) {
+		UCI_INTERNAL(uci_load, ctx, ptr->package, &ptr->p);
+		if (!ptr->p)
+			goto notfound;
+		ptr->last = &ptr->p->e;
+	} else {
+		ptr->p = uci_to_package(e);
+		ptr->last = e;
+	}
+
+	if (!ptr->section && !ptr->s)
+		goto complete;
+
+	/* if the section name validates as a regular name, pass through
+	 * to the regular uci_lookup function call */
+	if (ptr->s) {
+		e = &ptr->s->e;
+	} else if (ptr->flags & UCI_LOOKUP_EXTENDED) {
+		if (extended)
+			e = uci_lookup_ext_section(ctx, ptr);
+		else
+			UCI_THROW(ctx, UCI_ERR_INVAL);
+	} else {
+		e = uci_lookup_list(&ptr->p->sections, ptr->section);
+	}
+
 	if (!e)
-		goto notfound;
+		goto abort;
 
-	if (option) {
-		s = uci_to_section(e);
-		e = uci_lookup_list(ctx, &s->options, option);
+	ptr->last = e;
+	ptr->s = uci_to_section(e);
+
+	if (ptr->option) {
+		e = uci_lookup_list(&ptr->s->options, ptr->option);
+		if (!e)
+			goto abort;
+
+		ptr->o = uci_to_option(e);
+		ptr->last = e;
 	}
 
-	*res = e;
+complete:
+	ptr->flags |= UCI_LOOKUP_COMPLETE;
+abort:
 	return 0;
 
 notfound:
@@ -262,232 +440,267 @@ notfound:
 	return 0;
 }
 
-int uci_del_element(struct uci_context *ctx, struct uci_element *e)
+__private struct uci_element *
+uci_expand_ptr(struct uci_context *ctx, struct uci_ptr *ptr, bool complete)
 {
-	/* NB: UCI_INTERNAL use means without history tracking */
-	bool internal = ctx->internal;
-	struct uci_package *p = NULL;
-	struct uci_section *s = NULL;
-	struct uci_option *o = NULL;
-	struct uci_element *i, *tmp;
-	char *option = NULL;
+	UCI_ASSERT(ctx, ptr != NULL);
 
-	UCI_HANDLE_ERR(ctx);
-	UCI_ASSERT(ctx, e != NULL);
+	if (!(ptr->flags & UCI_LOOKUP_DONE))
+		UCI_INTERNAL(uci_lookup_ptr, ctx, ptr, NULL, 1);
+	if (complete && !(ptr->flags & UCI_LOOKUP_COMPLETE))
+		UCI_THROW(ctx, UCI_ERR_NOTFOUND);
+	UCI_ASSERT(ctx, ptr->p != NULL);
+
+	/* fill in missing string info */
+	if (ptr->p && !ptr->package)
+		ptr->package = ptr->p->e.name;
+	if (ptr->s && !ptr->section)
+		ptr->section = ptr->s->e.name;
+	if (ptr->o && !ptr->option)
+		ptr->option = ptr->o->e.name;
+
+	if (ptr->o)
+		return &ptr->o->e;
+	if (ptr->s)
+		return &ptr->s->e;
+	if (ptr->p)
+		return &ptr->p->e;
+	else
+		return NULL;
+}
 
-	switch(e->type) {
-	case UCI_TYPE_SECTION:
-		s = uci_to_section(e);
-		uci_foreach_element_safe(&s->options, tmp, i) {
-			uci_del_element(ctx, i);
-		}
-		break;
-	case UCI_TYPE_OPTION:
-		o = uci_to_option(e);
-		s = o->section;
-		p = s->package;
-		option = e->name;
-		break;
-	default:
-		UCI_THROW(ctx, UCI_ERR_INVAL);
-		break;
-	}
+static void uci_add_element_list(struct uci_context *ctx, struct uci_ptr *ptr, bool internal)
+{
+	struct uci_element *e;
+	struct uci_package *p;
 
-	p = s->package;
-	if (!internal)
-		uci_add_history(ctx, p, UCI_CMD_REMOVE, s->e.name, option, NULL);
+	p = ptr->p;
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_LIST_ADD, ptr->section, ptr->option, ptr->value);
 
-	switch(e->type) {
-	case UCI_TYPE_SECTION:
-		uci_free_section(s);
-		break;
-	case UCI_TYPE_OPTION:
-		uci_free_option(o);
-		break;
-	default:
-		break;
-	}
-	return 0;
+	e = uci_alloc_generic(ctx, UCI_TYPE_ITEM, ptr->value, sizeof(struct uci_option));
+	uci_list_add(&ptr->o->v.list, &e->list);
 }
 
-int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value)
+int uci_rename(struct uci_context *ctx, struct uci_ptr *ptr)
 {
-	/* NB: UCI_INTERNAL use means without history tracking */
-	bool internal = ctx->internal;
-	struct uci_list *list;
+	/* NB: UCI_INTERNAL use means without delta tracking */
+	bool internal = ctx && ctx->internal;
 	struct uci_element *e;
 	struct uci_package *p;
-	struct uci_section *s;
-	char *section;
-	char *option;
-	char *str;
-	int size;
+	char *n;
 
 	UCI_HANDLE_ERR(ctx);
-	UCI_ASSERT(ctx, (element != NULL) && (*element != NULL));
-
-	/* what the 'value' of an element means depends on the type
-	 * for a section, the 'value' means its type
-	 * for an option, the 'value' means its value string
-	 * when changing the value, shrink the element to its actual size
-	 * (it may have been allocated with a bigger size, to include
-	 *  its buffer)
-	 * then duplicate the string passed on the command line and
-	 * insert it into the structure.
-	 */
-	e = *element;
-	list = e->list.prev;
-	switch(e->type) {
-	case UCI_TYPE_SECTION:
-		UCI_ASSERT(ctx, uci_validate_name(value));
-		size = sizeof(struct uci_section);
-		s = uci_to_section(e);
-		section = e->name;
-		option = NULL;
-		break;
-	case UCI_TYPE_OPTION:
-		UCI_ASSERT(ctx, value != NULL);
-		size = sizeof(struct uci_option);
-		s = uci_to_option(e)->section;
-		section = s->e.name;
-		option = e->name;
-		break;
-	default:
-		UCI_THROW(ctx, UCI_ERR_INVAL);
-		return 0;
-	}
-	p = s->package;
-	if (!internal)
-		uci_add_history(ctx, p, UCI_CMD_CHANGE, section, option, value);
 
-	uci_list_del(&e->list);
-	e = uci_realloc(ctx, e, size);
-	str = uci_strdup(ctx, value);
-	uci_list_insert(list, &e->list);
-	*element = e;
+	e = uci_expand_ptr(ctx, ptr, true);
+	p = ptr->p;
 
-	switch(e->type) {
-	case UCI_TYPE_SECTION:
-		uci_to_section(e)->type = str;
-		break;
-	case UCI_TYPE_OPTION:
-		uci_to_option(e)->value = str;
-		break;
-	default:
-		break;
-	}
+	UCI_ASSERT(ctx, ptr->s);
+	UCI_ASSERT(ctx, ptr->value);
+
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_RENAME, ptr->section, ptr->option, ptr->value);
+
+	n = uci_strdup(ctx, ptr->value);
+	if (e->name)
+		free(e->name);
+	e->name = n;
+
+	if (e->type == UCI_TYPE_SECTION)
+		uci_to_section(e)->anonymous = false;
 
 	return 0;
 }
 
-int uci_rename(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *name)
+int uci_reorder_section(struct uci_context *ctx, struct uci_section *s, int pos)
 {
-	/* NB: UCI_INTERNAL use means without history tracking */
-	bool internal = ctx->internal;
-	struct uci_element *e;
+	struct uci_package *p = s->package;
+	char order[32];
 
 	UCI_HANDLE_ERR(ctx);
 
-	/* NB: p, section, option validated by uci_lookup */
-	UCI_INTERNAL(uci_lookup, ctx, &e, p, section, option);
+	uci_list_set_pos(&s->package->sections, &s->e.list, pos);
+	if (!ctx->internal && p->has_delta) {
+		sprintf(order, "%d", pos);
+		uci_add_delta(ctx, &p->delta, UCI_CMD_REORDER, s->e.name, NULL, order);
+	}
+
+	return 0;
+}
 
-	if (!internal)
-		uci_add_history(ctx, p, UCI_CMD_RENAME, section, option, name);
+int uci_add_section(struct uci_context *ctx, struct uci_package *p, const char *type, struct uci_section **res)
+{
+	bool internal = ctx && ctx->internal;
+	struct uci_section *s;
 
-	name = uci_strdup(ctx, name);
-	if (e->name)
-		free(e->name);
-	e->name = name;
+	UCI_HANDLE_ERR(ctx);
+	UCI_ASSERT(ctx, p != NULL);
+	s = uci_alloc_section(p, type, NULL);
+	uci_fixup_section(ctx, s);
+	*res = s;
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_ADD, s->e.name, NULL, type);
 
 	return 0;
 }
 
-
-int uci_delete(struct uci_context *ctx, struct uci_package *p, char *section, char *option)
+int uci_delete(struct uci_context *ctx, struct uci_ptr *ptr)
 {
 	/* NB: pass on internal flag to uci_del_element */
-	bool internal = ctx->internal;
+	bool internal = ctx && ctx->internal;
+	struct uci_package *p;
 	struct uci_element *e;
 
 	UCI_HANDLE_ERR(ctx);
 
-	/* NB: p, section, option validated by uci_lookup */
-	UCI_INTERNAL(uci_lookup, ctx, &e, p, section, option);
+	e = uci_expand_ptr(ctx, ptr, true);
+	p = ptr->p;
+
+	UCI_ASSERT(ctx, ptr->s);
+
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_REMOVE, ptr->section, ptr->option, NULL);
 
-	ctx->internal = internal;
-	return uci_del_element(ctx, e);
+	uci_free_any(&e);
+
+	if (ptr->option)
+		ptr->o = NULL;
+	else if (ptr->section)
+		ptr->s = NULL;
+
+	return 0;
 }
 
-int uci_set(struct uci_context *ctx, struct uci_package *p, char *section, char *option, char *value)
+int uci_add_list(struct uci_context *ctx, struct uci_ptr *ptr)
 {
-	/* NB: UCI_INTERNAL use means without history tracking */
-	bool internal = ctx->internal;
-	struct uci_element *e = NULL;
-	struct uci_section *s = NULL;
-	struct uci_option *o = NULL;
+	/* NB: UCI_INTERNAL use means without delta tracking */
+	bool internal = ctx && ctx->internal;
+	struct uci_option *prev = NULL;
+	const char *value2 = NULL;
 
 	UCI_HANDLE_ERR(ctx);
-	UCI_ASSERT(ctx, p != NULL);
-	UCI_ASSERT(ctx, uci_validate_name(section));
-	if (option) {
-		UCI_ASSERT(ctx, uci_validate_name(option));
-		UCI_ASSERT(ctx, value != NULL);
-	} else {
-		UCI_ASSERT(ctx, uci_validate_name(value));
+
+	uci_expand_ptr(ctx, ptr, false);
+	UCI_ASSERT(ctx, ptr->s);
+	UCI_ASSERT(ctx, ptr->value);
+
+	if (ptr->o) {
+		switch (ptr->o->type) {
+		case UCI_TYPE_STRING:
+			/* we already have a string value, convert that to a list */
+			prev = ptr->o;
+			value2 = ptr->value;
+			ptr->value = ptr->o->v.string;
+			break;
+		case UCI_TYPE_LIST:
+			uci_add_element_list(ctx, ptr, internal);
+			return 0;
+		default:
+			UCI_THROW(ctx, UCI_ERR_INVAL);
+			break;
+		}
 	}
 
-	/*
-	 * look up the package, section and option (if set)
-	 * if the section/option is to be modified and it is not found
-	 * create a new element in the appropriate list
-	 */
-	e = uci_lookup_list(ctx, &p->sections, section);
-	if (!e)
-		goto notfound;
+	ptr->o = uci_alloc_list(ptr->s, ptr->option);
+	if (prev) {
+		uci_add_element_list(ctx, ptr, true);
+		uci_free_option(prev);
+		ptr->value = value2;
+	}
+	uci_add_element_list(ctx, ptr, internal);
 
-	s = uci_to_section(e);
-	if (ctx->pctx)
-		ctx->pctx->section = s;
+	return 0;
+}
 
-	if (option) {
-		e = uci_lookup_list(ctx, &s->options, option);
-		if (!e)
-			goto notfound;
-		o = uci_to_option(e);
+int uci_del_list(struct uci_context *ctx, struct uci_ptr *ptr)
+{
+	/* NB: pass on internal flag to uci_del_element */
+	bool internal = ctx && ctx->internal;
+	struct uci_element *e, *tmp;
+	struct uci_package *p;
+
+	UCI_HANDLE_ERR(ctx);
+
+	uci_expand_ptr(ctx, ptr, false);
+	UCI_ASSERT(ctx, ptr->s);
+	UCI_ASSERT(ctx, ptr->value);
+
+	if (!(ptr->o && ptr->option))
+		return 0;
+
+	if ((ptr->o->type != UCI_TYPE_LIST))
+		return 0;
+
+	p = ptr->p;
+	if (!internal && p->has_delta)
+		uci_add_delta(ctx, &p->delta, UCI_CMD_LIST_DEL, ptr->section, ptr->option, ptr->value);
+
+	uci_foreach_element_safe(&ptr->o->v.list, tmp, e) {
+		if (!strcmp(ptr->value, uci_to_option(e)->e.name)) {
+			uci_free_option(uci_to_option(e));
+		}
 	}
 
-	/* 
-	 * no unknown element was supplied, assume that we can just update 
-	 * an existing entry
-	 */
-	if (o)
-		e = &o->e;
-	else
-		e = &s->e;
+	return 0;
+}
 
-	ctx->internal = internal;
-	return uci_set_element_value(ctx, &e, value);
+int uci_set(struct uci_context *ctx, struct uci_ptr *ptr)
+{
+	/* NB: UCI_INTERNAL use means without delta tracking */
+	bool internal = ctx && ctx->internal;
 
-notfound:
-	/* 
-	 * the entry that we need to update was not found,
-	 * check if the search failed prematurely.
-	 * this can happen if the package was not found, or if
-	 * an option was supplied, but the section wasn't found
-	 */
-	if (!p || (!s && option))
-		UCI_THROW(ctx, UCI_ERR_NOTFOUND);
+	UCI_HANDLE_ERR(ctx);
+	uci_expand_ptr(ctx, ptr, false);
+	UCI_ASSERT(ctx, ptr->value);
+	UCI_ASSERT(ctx, ptr->s || (!ptr->option && ptr->section));
+	if (!ptr->option && ptr->value[0]) {
+		UCI_ASSERT(ctx, uci_validate_type(ptr->value));
+	}
 
-	/* now add the missing entry */
-	if (!internal)
-		uci_add_history(ctx, p, UCI_CMD_ADD, section, option, value);
-	if (s)
-		uci_alloc_option(s, option, value);
-	else {
-		s = uci_alloc_section(p, value, section);
-		if (ctx->pctx)
-			ctx->pctx->section = s;
+	if (!ptr->o && ptr->s && ptr->option) {
+		struct uci_element *e;
+		e = uci_lookup_list(&ptr->s->options, ptr->option);
+		if (e)
+			ptr->o = uci_to_option(e);
 	}
+	if (!ptr->value[0]) {
+		/* if setting a nonexistant option/section to a nonexistant value,
+		 * exit without errors */
+		if (!(ptr->flags & UCI_LOOKUP_COMPLETE))
+			return 0;
+
+		return uci_delete(ctx, ptr);
+	} else if (!ptr->o && ptr->option) { /* new option */
+		ptr->o = uci_alloc_option(ptr->s, ptr->option, ptr->value);
+		ptr->last = &ptr->o->e;
+	} else if (!ptr->s && ptr->section) { /* new section */
+		ptr->s = uci_alloc_section(ptr->p, ptr->value, ptr->section);
+		ptr->last = &ptr->s->e;
+	} else if (ptr->o && ptr->option) { /* update option */
+		if ((ptr->o->type == UCI_TYPE_STRING) &&
+			!strcmp(ptr->o->v.string, ptr->value))
+			return 0;
+		uci_free_option(ptr->o);
+		ptr->o = uci_alloc_option(ptr->s, ptr->option, ptr->value);
+		ptr->last = &ptr->o->e;
+	} else if (ptr->s && ptr->section) { /* update section */
+		char *s = uci_strdup(ctx, ptr->value);
+
+		if (ptr->s->type == uci_dataptr(ptr->s)) {
+			ptr->last = NULL;
+			ptr->last = uci_realloc(ctx, ptr->s, sizeof(struct uci_section));
+			ptr->s = uci_to_section(ptr->last);
+			uci_list_fixup(&ptr->s->e.list);
+		} else {
+			free(ptr->s->type);
+		}
+		ptr->s->type = s;
+	} else {
+		UCI_THROW(ctx, UCI_ERR_INVAL);
+	}
+
+	if (!internal && ptr->p->has_delta)
+		uci_add_delta(ctx, &ptr->p->delta, UCI_CMD_CHANGE, ptr->section, ptr->option, ptr->value);
 
 	return 0;
 }