/* SPDX-License-Identifier: GPL-2.0 */

/*

 * bpf_glue.c:	BPF code to call both legacy and libbpf code

 * Authors:	Hangbin Liu <haliu@redhat.com>

 *

 */

#include <limits.h>

#include "bpf_util.h"

#ifdef HAVE_LIBBPF

#include <bpf/bpf.h>

#endif

int bpf_program_load(enum bpf_prog_type type, const struct bpf_insn *insns,

		     size_t size_insns, const char *license, char *log,

		     size_t size_log)

{

#ifdef HAVE_LIBBPF

	return bpf_load_program(type, insns, size_insns / sizeof(struct bpf_insn),

				license, 0, log, size_log);

#else

	return bpf_prog_load_dev(type, insns, size_insns, license, 0, log, size_log);

#endif

}

int bpf_program_attach(int prog_fd, int target_fd, enum bpf_attach_type type)

{

#ifdef HAVE_LIBBPF

	return bpf_prog_attach(prog_fd, target_fd, type, 0);

#else

	return bpf_prog_attach_fd(prog_fd, target_fd, type);

#endif

}

#ifdef HAVE_LIBBPF

static const char *_libbpf_compile_version = LIBBPF_VERSION;

static char _libbpf_version[10] = {};

const char *get_libbpf_version(void)

{

	/* Start by copying compile-time version into buffer so we have a

	 * fallback value in case we are dynamically linked, or can't find a

	 * version in /proc/self/maps below.

	 */

	strncpy(_libbpf_version, _libbpf_compile_version,

		sizeof(_libbpf_version)-1);

#ifdef LIBBPF_DYNAMIC

	char buf[PATH_MAX], *s;

	bool found = false;

	FILE *fp;

	/* When dynamically linking against libbpf, we can't be sure that the

	 * version we discovered at compile time is actually the one we are

	 * using at runtime. This can lead to hard-to-debug errors, so we try to

	 * discover the correct version at runtime.

	 *

	 * The simple solution to this would be if libbpf itself exported a

	 * version in its API. But since it doesn't, we work around this by

	 * parsing the mappings of the binary at runtime, looking for the full

	 * filename of libbpf.so and using that.

	 */

	fp = fopen("/proc/self/maps", "r");

	if (fp == NULL)

		goto out;

	while ((s = fgets(buf, sizeof(buf), fp)) != NULL) {

		if ((s = strstr(buf, "libbpf.so.")) != NULL) {

			strncpy(_libbpf_version, s+10, sizeof(_libbpf_version)-1);

			strtok(_libbpf_version, "\n");

			found = true;

			break;

		}

	}

	fclose(fp);

out:

	if (!found)

		fprintf(stderr, "Couldn't find runtime libbpf version - falling back to compile-time value!\n");

#endif /* LIBBPF_DYNAMIC */

	_libbpf_version[sizeof(_libbpf_version)-1] = '\0';

	return _libbpf_version;

}

#else

const char *get_libbpf_version(void)

{

	return NULL;

}

#endif /* HAVE_LIBBPF */