implement uci_set, improve error handling

3 files changed, 180 insertions, 11 deletions

diff --git a/libuci.c b/libuci.c
index 400acd8..c0b4ab0 100644
--- a/libuci.c
+++ b/libuci.c
@@ -73,7 +73,7 @@ int uci_cleanup(struct uci_context *ctx)
 	return 0;
 }
 
-void uci_perror(struct uci_context *ctx, const char *str)
+void uci_perror(struct uci_context *ctx, const char *prefix)
 {
 	int err;
 
@@ -85,15 +85,20 @@ void uci_perror(struct uci_context *ctx, const char *str)
 	if ((err < 0) || (err >= UCI_ERR_LAST))
 		err = UCI_ERR_UNKNOWN;
 
+	if (prefix)
+		fprintf(stderr, "%s: ", prefix);
+	if (ctx->func)
+		fprintf(stderr, "%s: ", ctx->func);
+
 	switch (err) {
 	case UCI_ERR_PARSE:
 		if (ctx->pctx) {
-			fprintf(stderr, "%s: %s (%s) at line %d, byte %d\n", str, uci_errstr[err], (ctx->pctx->reason ? ctx->pctx->reason : "unknown"), ctx->pctx->line, ctx->pctx->byte);
+			fprintf(stderr, "%s (%s) at line %d, byte %d\n", uci_errstr[err], (ctx->pctx->reason ? ctx->pctx->reason : "unknown"), ctx->pctx->line, ctx->pctx->byte);
 			break;
 		}
 		/* fall through */
 	default:
-		fprintf(stderr, "%s: %s\n", str, uci_errstr[err]);
+		fprintf(stderr, "%s\n", uci_errstr[err]);
 		break;
 	}
 }
diff --git a/list.c b/list.c
index 0591061..5561778 100644
--- a/list.c
+++ b/list.c
@@ -21,7 +21,7 @@ static inline void uci_list_init(struct uci_list *ptr)
 	ptr->next = ptr;
 }
 
-/* inserts a new list entry between two consecutive entries */
+/* 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;
@@ -50,6 +50,10 @@ static inline void uci_list_del(struct uci_list *ptr)
 	uci_list_init(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 *
 uci_alloc_generic(struct uci_context *ctx, int type, const char *name, int size)
 {
@@ -137,6 +141,7 @@ 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);
 	return p;
 }
 
@@ -154,6 +159,21 @@ uci_free_package(struct uci_package *p)
 	uci_free_element(&p->e);
 }
 
+/* record a change that was done to a package */
+static inline void
+uci_add_history(struct uci_context *ctx, struct uci_package *p, int cmd, char *section, char *option, char *value)
+{
+	struct uci_history *h = (struct uci_history *) uci_malloc(ctx, sizeof(struct uci_history));
+
+	uci_list_init(&h->list);
+	h->cmd = cmd;
+	h->section = section;
+	h->option = option;
+	h->value = value;
+	uci_list_add(&p->history, &h->list);
+}
+
+
 static struct uci_element *uci_lookup_list(struct uci_context *ctx, struct uci_list *list, char *name)
 {
 	struct uci_element *e;
@@ -193,6 +213,131 @@ found:
 	return 0;
 }
 
+int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value)
+{
+	int size;
+	char *str;
+	struct uci_list *list;
+	struct uci_element *e;
+
+	UCI_HANDLE_ERR(ctx);
+	UCI_ASSERT(ctx, value != NULL);
+	UCI_ASSERT(ctx, element != NULL);
+	UCI_ASSERT(ctx, *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:
+		size = sizeof(struct uci_section);
+		break;
+	case UCI_TYPE_OPTION:
+		size = sizeof(struct uci_option);
+		break;
+	default:
+		UCI_THROW(ctx, UCI_ERR_INVAL);
+		break;
+	}
+
+	uci_list_del(&e->list);
+	e = uci_realloc(ctx, e, size);
+	str = uci_strdup(ctx, value);
+	uci_list_insert(list, &e->list);
+	*element = e;
+
+	switch(e->type) {
+	case UCI_TYPE_SECTION:
+		uci_to_section(e)->type = value;
+		break;
+	case UCI_TYPE_OPTION:
+		uci_to_option(e)->value = value;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+int uci_set(struct uci_context *ctx, char *package, char *section, char *option, char *value)
+{
+	struct uci_element *e;
+	struct uci_package *p = NULL;
+	struct uci_section *s = NULL;
+	struct uci_option *o = NULL;
+	struct uci_history *h;
+
+	UCI_HANDLE_ERR(ctx);
+	UCI_ASSERT(ctx, package != NULL);
+	UCI_ASSERT(ctx, section != NULL);
+
+	fprintf(stderr, "uci_set: '%s' '%s' '%s' = '%s'\n", package, section, option, value);
+
+	/*
+	 * 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
+	 */
+	UCI_TRAP_SAVE(ctx, notfound);
+	e = uci_lookup_list(ctx, &ctx->root, package);
+	if (!e)
+		goto notfound;
+
+	p = uci_to_package(e);
+	e = uci_lookup_list(ctx, &p->sections, section);
+	if (!e)
+		goto notfound;
+	s = uci_to_section(e);
+
+	if (option) {
+		e = uci_lookup_list(ctx, &s->options, option);
+		if (!e)
+			goto notfound;
+		o = uci_to_option(e);
+	}
+	UCI_TRAP_RESTORE(ctx);
+
+	/* 
+	 * no unknown element was supplied, assume that we can just update 
+	 * an existing entry
+	 */
+	if (o)
+		e = &o->e;
+	else
+		e = &s->e;
+
+	uci_add_history(ctx, p, UCI_CMD_CHANGE, section, option, value);
+	return uci_set_element_value(ctx, &e, value);
+
+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, ctx->errno);
+
+	/* now add the missing entry */
+	uci_add_history(ctx, p, UCI_CMD_ADD, section, option, value);
+	if (s)
+		uci_alloc_option(s, option, value);
+	else
+		uci_alloc_section(p, section, value);
+
+	return 0;
+}
+
 int uci_unload(struct uci_context *ctx, const char *name)
 {
 	struct uci_element *e;
@@ -212,4 +357,3 @@ found:
 	return 0;
 }
 
-
diff --git a/uci.h b/uci.h
index 021e5b3..6a6db67 100644
--- a/uci.h
+++ b/uci.h
@@ -136,6 +136,27 @@ extern int uci_cleanup(struct uci_context *ctx);
 extern int uci_lookup(struct uci_context *ctx, struct uci_element **res, char *package, char *section, char *option);
 
 /**
+ * uci_set_element_value: Replace an element's value with a new one
+ * @ctx: uci context
+ * @element: pointer to an uci_element struct pointer
+ * @value: new value
+ * 
+ * Only valid for uci_option and uci_section. Will replace the type string
+ * when used with an uci_section
+ */
+extern int uci_set_element_value(struct uci_context *ctx, struct uci_element **element, char *value);
+
+/**
+ * uci_set: Set an element's value; create the element if necessary
+ * @ctx: uci context
+ * @package: package name
+ * @section: section name
+ * @option: option name
+ * @value: value (option) or type (section)
+ */
+extern int uci_set(struct uci_context *ctx, char *package, char *section, char *option, char *value);
+
+/**
  * uci_list_configs: List available uci config files
  *
  * @ctx: uci context
@@ -166,6 +187,7 @@ struct uci_context
 
 	/* private: */
 	int errno;
+	const char *func;
 	jmp_buf trap;
 	char *buf;
 	int bufsz;
@@ -194,6 +216,7 @@ struct uci_package
 	struct uci_context *ctx;
 	/* private: */
 	int n_section;
+	struct uci_list history;
 };
 
 struct uci_section
@@ -221,12 +244,9 @@ struct uci_history
 {
 	struct uci_list list;
 	enum uci_command cmd;
-	union {
-		struct uci_element element;
-		struct uci_package package;
-		struct uci_section section;
-		struct uci_option option;
-	} data;
+	char *section;
+	char *option;
+	char *value;
 };
 
 /* linked list handling */