[RFC][PATCH bpf-next] libbpf: add bpf_object__open_{file,mem} w/ sized opts

@@ -255,7 +255,7 @@ struct bpf_object {
 	 */
 	struct {
 		int fd;
-		void *obj_buf;
+		const void *obj_buf;
 		size_t obj_buf_sz;
 		Elf *elf;
 		GElf_Ehdr ehdr;

@@ -492,7 +492,7 @@ bpf_object__init_prog_names(struct bpf_object *obj)
 }
 
 static struct bpf_object *bpf_object__new(const char *path,
-					  void *obj_buf,
+					  const void *obj_buf,
 					  size_t obj_buf_sz)
 {
 	struct bpf_object *obj;

@@ -569,7 +569,7 @@ static int bpf_object__elf_init(struct bpf_object *obj)
 		 * obj_buf should have been validated by
 		 * bpf_object__open_buffer().
 		 */
-		obj->efile.elf = elf_memory(obj->efile.obj_buf,
+		obj->efile.elf = elf_memory((char *)obj->efile.obj_buf,
 					    obj->efile.obj_buf_sz);
 	} else {
 		obj->efile.fd = open(obj->path, O_RDONLY);

@@ -3597,7 +3597,7 @@ static int bpf_object__validate(struct bpf_object *obj, bool needs_kver)
 }
 
 static struct bpf_object *
-__bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz,
+__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
 		   bool needs_kver, int flags)
 {
 	struct bpf_object *obj;

@@ -3655,25 +3655,59 @@ struct bpf_object *bpf_object__open(const char *path)
 	return bpf_object__open_xattr(&attr);
 }
 
-struct bpf_object *bpf_object__open_buffer(void *obj_buf,
-					   size_t obj_buf_sz,
-					   const char *name)
+struct bpf_object *
+bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts)
+{
+	if (!OPTS_VALID(opts) || !path)
+		return ERR_PTR(-EINVAL);
+
+	pr_debug("loading %s\n", path);
+
+	return __bpf_object__open(path, NULL, 0, false, 0);
+}
+
+static struct bpf_object *
+__bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
+		       struct bpf_object_open_opts *opts, bool enforce_kver)
 {
 	char tmp_name[64];
+	const char *name;
 
-	/* param validation */
-	if (!obj_buf || obj_buf_sz <= 0)
-		return NULL;
+	if (!OPTS_VALID(opts) || !obj_buf || obj_buf_sz == 0)
+		return ERR_PTR(-EINVAL);
 
+	name = OPTS_GET(opts, object_name, NULL);
 	if (!name) {
 		snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
 			 (unsigned long)obj_buf,
 			 (unsigned long)obj_buf_sz);
 		name = tmp_name;
 	}
+
 	pr_debug("loading object '%s' from buffer\n", name);
 
-	return __bpf_object__open(name, obj_buf, obj_buf_sz, true, true);
+	return __bpf_object__open(name, obj_buf, obj_buf_sz, enforce_kver, 0);
+}
+
+struct bpf_object *
+bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
+		     struct bpf_object_open_opts *opts)
+{
+	return __bpf_object__open_mem(obj_buf, obj_buf_sz, opts, false);
+}
+
+struct bpf_object *
+bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz, const char *name)
+{
+	struct bpf_object_open_opts opts = {
+		.sz = sizeof(struct bpf_object_open_opts),
+		.object_name = name,
+	};
+
+	if (!obj_buf || obj_buf_sz == 0)
+		return NULL;
+
+	return __bpf_object__open_mem(obj_buf, obj_buf_sz, &opts, true);
 }
 
 int bpf_object__unload(struct bpf_object *obj)

@@ -67,14 +67,37 @@ struct bpf_object_open_attr {
 	enum bpf_prog_type prog_type;
 };
 
+struct bpf_object_open_opts {
+	/* size of this struct, for forward and backward compatiblity */
+	size_t sz;
+	/* object name override, if provided:
+	 * - for object open from file, this will override setting object
+	 *   name from file path's base name;
+	 * - for object open from memory buffer, this will specify an object
+	 *   name and will override default "<addr>-<buf-size>" name;
+	 */
+	const char *object_name;
+	/* program type to use if determination based on program name doesn't
+	 * work */
+	enum bpf_prog_type fallback_prog_type;
+};
+
 LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
 LIBBPF_API struct bpf_object *
+bpf_object__open_file(const char *path, struct bpf_object_open_opts *opts);
+LIBBPF_API struct bpf_object *
+bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
+		     struct bpf_object_open_opts *opts);
+
+/* deprecated bpf_object__open variants */
+LIBBPF_API struct bpf_object *
+bpf_object__open_buffer(const void *obj_buf, size_t obj_buf_sz,
+			const char *name);
+LIBBPF_API struct bpf_object *
 bpf_object__open_xattr(struct bpf_object_open_attr *attr);
-struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr,
-					    int flags);
-LIBBPF_API struct bpf_object *bpf_object__open_buffer(void *obj_buf,
-						      size_t obj_buf_sz,
-						      const char *name);
+struct bpf_object *
+__bpf_object__open_xattr(struct bpf_object_open_attr *attr, int flags);
+
 int bpf_object__section_size(const struct bpf_object *obj, const char *name,
 			     __u32 *size);
 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,

@@ -190,3 +190,9 @@ LIBBPF_0.0.5 {
 	global:
 		bpf_btf_get_next_id;
 } LIBBPF_0.0.4;
+
+LIBBPF_0.0.6 {
+	global:
+		bpf_object__open_file;
+		bpf_object__open_mem;
+} LIBBPF_0.0.5;

@@ -47,6 +47,12 @@ do {				\
 #define pr_info(fmt, ...)	__pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
 #define pr_debug(fmt, ...)	__pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
 
+#define OPTS_VALID(opts) (!(opts) || (opts)->sz >= sizeof((opts)->sz))
+#define OPTS_HAS(opts, field) \
+	((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
+#define OPTS_GET(opts, field, fallback_value) \
+	(OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
+
 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
 			 const char *str_sec, size_t str_len);