Add support to output data in JSON. This is still work in progress and

the output structures may still change but it should be a good starting
point for poeple to start playing with it.
OK benno@, job@, deraadt@

1 files changed, 224 insertions, 0 deletions

diff --git a/usr.sbin/bgpctl/json.c b/usr.sbin/bgpctl/json.c
new file mode 100644
index 00000000000..106fd2f7729
--- /dev/null
+++ b/usr.sbin/bgpctl/json.c
@@ -0,0 +1,224 @@
+/*
+ * Copyright (c) 2020 Claudio Jeker <claudio@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <err.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "json.h"
+
+#define JSON_MAX_STACK	16
+
+enum json_type {
+	NONE,
+	START,
+	ARRAY,
+	OBJECT
+};
+
+struct json_stack {
+	const char	*name;
+	unsigned int	count;
+	enum json_type	type;
+} stack[JSON_MAX_STACK];
+
+char indent[JSON_MAX_STACK + 1];
+int level;
+
+static void
+do_comma_indent(void)
+{
+	if (stack[level].count++ > 0)
+		printf(",\n");
+	printf("\t%.*s", level, indent);
+}
+
+static void
+do_name(const char *name)
+{
+	if (stack[level].type == ARRAY)
+		return;
+	printf("\"%s\": ", name);
+}
+
+static int
+do_find(enum json_type type, const char *name)
+{
+	int i;
+
+	for (i = level; i > 0; i--)
+		if (type == stack[i].type &&
+		    strcmp(name, stack[i].name) == 0)
+			return i;
+
+	/* not found */
+	return -1;
+}
+
+void
+json_do_start(void)
+{
+	memset(indent, '\t', JSON_MAX_STACK);
+	memset(stack, 0, sizeof(stack));
+	level = 0;
+	stack[level].type = START;
+
+	printf("{\n");
+}
+
+void
+json_do_finish(void)
+{
+	while (level > 0)
+		json_do_end();
+	printf("\n}\n");
+}
+
+void
+json_do_array(const char *name)
+{
+	int i, l;
+
+	if ((l = do_find(ARRAY, name)) > 0) {
+		/* array already in use, close element and move on */
+		for (i = level - l; i > 0; i--)
+			json_do_end();
+		return;
+	}
+	/* Do not stack arrays, while allowed this is not needed */
+	if (stack[level].type == ARRAY)
+		json_do_end();
+
+	do_comma_indent();
+	do_name(name);
+	printf("[\n");
+
+	if (++level >= JSON_MAX_STACK)
+		errx(1, "json stack too deep");
+	
+	stack[level].name = name;
+	stack[level].type = ARRAY;
+	stack[level].count = 0;
+}
+
+void
+json_do_object(const char *name)
+{
+	int i, l;
+
+	if ((l = do_find(OBJECT, name)) > 0) {
+		/* roll back to that object and close it */
+		for (i = level - l; i >= 0; i--)
+			json_do_end();
+	}
+
+	do_comma_indent();
+	do_name(name);
+	printf("{\n");
+
+	if (++level >= JSON_MAX_STACK)
+		errx(1, "json stack too deep");
+	
+	stack[level].name = name;
+	stack[level].type = OBJECT;
+	stack[level].count = 0;
+}
+
+void
+json_do_end(void)
+{
+	if (stack[level].type == ARRAY)
+		printf("\n%.*s]", level, indent);
+	else if (stack[level].type == OBJECT)
+		printf("\n%.*s}", level, indent);
+	else
+		errx(1, "json bad stack state");
+
+	stack[level].name = NULL;
+	stack[level].type = NONE;
+	stack[level].count = 0;
+
+	if (level-- <= 0)
+		errx(1, "json stack underflow");
+
+	stack[level].count++;
+}
+
+void
+json_do_printf(const char *name, const char *fmt, ...)
+{
+	va_list ap;
+
+	do_comma_indent();
+
+	do_name(name);
+	printf("\"");
+	va_start(ap, fmt);
+	vprintf(fmt, ap);
+	va_end(ap);
+	printf("\"");
+}
+
+void
+json_do_hexdump(const char *name, void *buf, size_t len)
+{
+	uint8_t *data = buf;
+	size_t i;
+
+	do_comma_indent();
+	do_name(name);
+	printf("\"");
+	for (i=0; i < len; i++)
+		printf("%02x", *(data+i));
+	printf("\"");
+}
+
+void
+json_do_bool(const char *name, int v)
+{
+	do_comma_indent();
+	do_name(name);
+	if (v)
+		printf("true");
+	else
+		printf("false");
+}
+
+void
+json_do_uint(const char *name, uint64_t v)
+{
+	do_comma_indent();
+	do_name(name);
+	printf("%llu", v);
+}
+
+void
+json_do_int(const char *name, int64_t v)
+{
+	do_comma_indent();
+	do_name(name);
+	printf("%lld", v);
+}
+
+void
+json_do_double(const char *name, double v)
+{
+	do_comma_indent();
+	do_name(name);
+	printf("%f", v);
+}