Add a json_object_from_fd_ex() function, to allow the max nesting depth to be specified.

json_util.c

@@ -82,6 +82,10 @@ void _json_c_set_last_err(const char *err_fmt, ...)
 }
 
 struct json_object* json_object_from_fd(int fd)
+{
+	return json_object_from_fd_ex(fd, -1);
+}
+struct json_object* json_object_from_fd_ex(int fd, int in_depth)
 {
   struct printbuf *pb;
   struct json_object *obj;
@@ -92,15 +96,33 @@ struct json_object* json_object_from_fd(int fd)
     _json_c_set_last_err("json_object_from_file: printbuf_new failed\n");
     return NULL;
   }
+
+	int depth = JSON_TOKENER_DEFAULT_DEPTH;
+	if (in_depth != -1)
+		depth = in_depth;
+	json_tokener *tok = json_tokener_new_ex(depth);
+	if (!tok)
+	{
+		_json_c_set_last_err("json_object_from_fd: unable to allocate json_tokener(depth=%d): %s\n", depth, strerror(errno));
+		printbuf_free(pb);
+		return NULL;
+	}
+
   while((ret = read(fd, buf, JSON_FILE_BUF_SIZE)) > 0) {
     printbuf_memappend(pb, buf, ret);
   }
   if(ret < 0) {
     _json_c_set_last_err("json_object_from_fd: error reading fd %d: %s\n", fd, strerror(errno));
+	json_tokener_free(tok);
     printbuf_free(pb);
     return NULL;
   }
-  obj = json_tokener_parse(pb->buf);
+
+ 	obj = json_tokener_parse_ex(tok, pb->buf, printbuf_length(pb));
+	if (obj == NULL)
+		_json_c_set_last_err("json_tokener_parse_ex failed: %s\n", json_tokener_error_desc(json_tokener_get_error(tok)));
+
+	json_tokener_free(tok);
 	printbuf_free(pb);
 	return obj;
 }

json_util.h

@@ -50,8 +50,20 @@ JSON_EXPORT struct json_object* json_object_from_file(const char *filename);
  * Note, that the fd must be readable at the actual position, i.e.
  * use lseek(fd, 0, SEEK_SET) before.
  *
+ * The depth argument specifies the maximum object depth to pass to
+ * json_tokener_new_ex().  When depth == -1, JSON_TOKENER_DEFAULT_DEPTH
+ * is used instead.
+ *
  * Returns NULL on failure.  See json_util_get_last_err() for details.
  */
+JSON_EXPORT struct json_object* json_object_from_fd_ex(int fd, int depth);
+
+/**
+ * Create a JSON object from an already opened file descriptor, using
+ * the default maximum object depth. (JSON_TOKENER_DEFAULT_DEPTH)
+ *
+ * See json_object_from_fd_ex() for details.
+ */
 JSON_EXPORT struct json_object* json_object_from_fd(int fd);
 
 /**

tests/Makefile.am

@@ -36,6 +36,7 @@ EXTRA_DIST += $(TESTS)
 EXTRA_DIST += $(TESTS:.test=.expected)
 EXTRA_DIST += test-defs.sh
 EXTRA_DIST += valid.json
+EXTRA_DIST += valid_nested.json
 
 
 # Note: handled by test1.test

tests/test_util_file.c

@@ -5,6 +5,7 @@
 #include <stddef.h>
 #include <string.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -13,6 +14,7 @@
 #include "json_util.h"
 
 static void test_read_valid_with_fd(const char *testdir);
+static void test_read_valid_nested_with_fd(const char *testdir);
 static void test_read_nonexistant();
 static void test_read_closed(void);
 
@@ -129,6 +131,7 @@ int main(int argc, char **argv)
 	testdir = argv[1];
 
 	test_read_valid_with_fd(testdir);
+	test_read_valid_nested_with_fd(testdir);
 	test_read_nonexistant();
 	test_read_closed();
 	test_write_to_file();
@@ -137,7 +140,8 @@ int main(int argc, char **argv)
 
 static void test_read_valid_with_fd(const char *testdir)
 {
-	const char *filename = "./valid.json";
+	char filename[PATH_MAX];
+	(void)snprintf(filename, sizeof(filename), "%s/valid.json", testdir);
 
 	int d = open(filename, O_RDONLY, 0);
 	if (d < 0)
@@ -150,8 +154,8 @@ static void test_read_valid_with_fd(const char *testdir)
 	json_object *jso = json_object_from_fd(d);
 	if (jso != NULL)
 	{
-		printf("OK: json_object_from_fd(%s)=%s\n",
+		printf("OK: json_object_from_fd(valid.json)=%s\n",
-		       filename, json_object_to_json_string(jso));
+		       json_object_to_json_string(jso));
 		json_object_put(jso);
 	}
 	else
@@ -163,6 +167,50 @@ static void test_read_valid_with_fd(const char *testdir)
 	close(d);
 }
 
+static void test_read_valid_nested_with_fd(const char *testdir)
+{
+	char filename[PATH_MAX];
+	(void)snprintf(filename, sizeof(filename), "%s/valid_nested.json", testdir);
+
+	int d = open(filename, O_RDONLY, 0);
+	if (d < 0)
+	{
+		fprintf(stderr,
+			"FAIL: unable to open %s: %s\n",
+			filename, strerror(errno));
+		exit(EXIT_FAILURE);
+	}
+	json_object *jso = json_object_from_fd_ex(d, 20);
+	if (jso != NULL)
+	{
+		printf("OK: json_object_from_fd_ex(valid_nested.json, 20)=%s\n",
+		       json_object_to_json_string(jso));
+		json_object_put(jso);
+	}
+	else
+	{
+		fprintf(stderr,
+		        "FAIL: unable to parse contents of %s: %s\n",
+		        filename, json_util_get_last_err());
+	}
+
+	(void)lseek(d, SEEK_SET, 0);
+
+	jso = json_object_from_fd_ex(d, 3);
+	if (jso != NULL)
+	{
+		printf("FAIL: json_object_from_fd_ex(%s, 3)=%s\n",
+		       filename, json_object_to_json_string(jso));
+		json_object_put(jso);
+	}
+	else
+	{
+		printf("OK: correctly unable to parse contents of valid_nested.json with low max depth: %s\n",
+		        json_util_get_last_err());
+	}
+	close(d);
+}
+
 static void test_read_nonexistant()
 {
 	const char *filename = "./not_present.json";

tests/test_util_file.expected

@@ -1,4 +1,7 @@
-OK: json_object_from_fd(./valid.json)={ "foo": 123 }
+OK: json_object_from_fd(valid.json)={ "foo": 123 }
+OK: json_object_from_fd_ex(valid_nested.json, 20)={ "foo": 123, "obj2": { "obj3": { "obj4": { "foo": 999 } } } }
+OK: correctly unable to parse contents of valid_nested.json with low max depth: json_tokener_parse_ex failed: nesting too deep
+
 OK: json_object_from_file(./not_present.json) correctly returned NULL: json_object_from_file: error opening file ./not_present.json: ERRNO=ENOENT
 
 OK: json_object_from_fd(closed_fd), expecting NULL, EBADF, got:NULL, json_object_from_fd: error reading fd 10: ERRNO=EBADF

tests/valid_nested.json

@@ -0,0 +1 @@
+{"foo":123, "obj2": { "obj3": { "obj4": { "foo": 999 } } } }