bpftool: Allow to read btf as raw data

#include <libbpf.h>

#include <linux/btf.h>

#include <linux/hashtable.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include "btf.h"

#include "json_writer.h"

	return err;

}

static struct btf *btf__parse_raw(const char *file)

{

	struct btf *btf;

	struct stat st;

	__u8 *buf;

	FILE *f;

	if (stat(file, &st))

		return NULL;

	f = fopen(file, "rb");

	if (!f)

		return NULL;

	buf = malloc(st.st_size);

	if (!buf) {

		btf = ERR_PTR(-ENOMEM);

		goto exit_close;

	}

	if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) {

		btf = ERR_PTR(-EINVAL);

		goto exit_free;

	}

	btf = btf__new(buf, st.st_size);

exit_free:

	free(buf);

exit_close:

	fclose(f);

	return btf;

}

static bool is_btf_raw(const char *file)

{

	__u16 magic = 0;

	int fd;

	fd = open(file, O_RDONLY);

	if (fd < 0)

		return false;

	read(fd, &magic, sizeof(magic));

	close(fd);

	return magic == BTF_MAGIC;

}

static int do_dump(int argc, char **argv)

{

	struct btf *btf = NULL;

		}

		NEXT_ARG();

	} else if (is_prefix(src, "file")) {

		if (is_btf_raw(*argv))

			btf = btf__parse_raw(*argv);

		else

			btf = btf__parse_elf(*argv, NULL);

		if (IS_ERR(btf)) {

			err = PTR_ERR(btf);

			btf = NULL;