[Feature]add MT2731_MP2_MR2_SVN388 baseline version

Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/tools/lib/bpf/libbpf.c b/src/kernel/linux/v4.14/tools/lib/bpf/libbpf.c
new file mode 100644
index 0000000..701d29c
--- /dev/null
+++ b/src/kernel/linux/v4.14/tools/lib/bpf/libbpf.c
@@ -0,0 +1,1802 @@
+/*
+ * Common eBPF ELF object loading operations.
+ *
+ * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
+ * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
+ * Copyright (C) 2015 Huawei Inc.
+ * Copyright (C) 2017 Nicira, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License (not later!)
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not,  see <http://www.gnu.org/licenses>
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <libgen.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <asm/unistd.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/bpf.h>
+#include <linux/list.h>
+#include <linux/limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+#include <libelf.h>
+#include <gelf.h>
+
+#include "libbpf.h"
+#include "bpf.h"
+
+#ifndef EM_BPF
+#define EM_BPF 247
+#endif
+
+#ifndef BPF_FS_MAGIC
+#define BPF_FS_MAGIC		0xcafe4a11
+#endif
+
+#define __printf(a, b)	__attribute__((format(printf, a, b)))
+
+__printf(1, 2)
+static int __base_pr(const char *format, ...)
+{
+	va_list args;
+	int err;
+
+	va_start(args, format);
+	err = vfprintf(stderr, format, args);
+	va_end(args);
+	return err;
+}
+
+static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
+static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
+static __printf(1, 2) libbpf_print_fn_t __pr_debug;
+
+#define __pr(func, fmt, ...)	\
+do {				\
+	if ((func))		\
+		(func)("libbpf: " fmt, ##__VA_ARGS__); \
+} while (0)
+
+#define pr_warning(fmt, ...)	__pr(__pr_warning, fmt, ##__VA_ARGS__)
+#define pr_info(fmt, ...)	__pr(__pr_info, fmt, ##__VA_ARGS__)
+#define pr_debug(fmt, ...)	__pr(__pr_debug, fmt, ##__VA_ARGS__)
+
+void libbpf_set_print(libbpf_print_fn_t warn,
+		      libbpf_print_fn_t info,
+		      libbpf_print_fn_t debug)
+{
+	__pr_warning = warn;
+	__pr_info = info;
+	__pr_debug = debug;
+}
+
+#define STRERR_BUFSIZE  128
+
+#define ERRNO_OFFSET(e)		((e) - __LIBBPF_ERRNO__START)
+#define ERRCODE_OFFSET(c)	ERRNO_OFFSET(LIBBPF_ERRNO__##c)
+#define NR_ERRNO	(__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
+
+static const char *libbpf_strerror_table[NR_ERRNO] = {
+	[ERRCODE_OFFSET(LIBELF)]	= "Something wrong in libelf",
+	[ERRCODE_OFFSET(FORMAT)]	= "BPF object format invalid",
+	[ERRCODE_OFFSET(KVERSION)]	= "'version' section incorrect or lost",
+	[ERRCODE_OFFSET(ENDIAN)]	= "Endian mismatch",
+	[ERRCODE_OFFSET(INTERNAL)]	= "Internal error in libbpf",
+	[ERRCODE_OFFSET(RELOC)]		= "Relocation failed",
+	[ERRCODE_OFFSET(VERIFY)]	= "Kernel verifier blocks program loading",
+	[ERRCODE_OFFSET(PROG2BIG)]	= "Program too big",
+	[ERRCODE_OFFSET(KVER)]		= "Incorrect kernel version",
+	[ERRCODE_OFFSET(PROGTYPE)]	= "Kernel doesn't support this program type",
+};
+
+int libbpf_strerror(int err, char *buf, size_t size)
+{
+	if (!buf || !size)
+		return -1;
+
+	err = err > 0 ? err : -err;
+
+	if (err < __LIBBPF_ERRNO__START) {
+		int ret;
+
+		ret = strerror_r(err, buf, size);
+		buf[size - 1] = '\0';
+		return ret;
+	}
+
+	if (err < __LIBBPF_ERRNO__END) {
+		const char *msg;
+
+		msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
+		snprintf(buf, size, "%s", msg);
+		buf[size - 1] = '\0';
+		return 0;
+	}
+
+	snprintf(buf, size, "Unknown libbpf error %d", err);
+	buf[size - 1] = '\0';
+	return -1;
+}
+
+#define CHECK_ERR(action, err, out) do {	\
+	err = action;			\
+	if (err)			\
+		goto out;		\
+} while(0)
+
+
+/* Copied from tools/perf/util/util.h */
+#ifndef zfree
+# define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
+#endif
+
+#ifndef zclose
+# define zclose(fd) ({			\
+	int ___err = 0;			\
+	if ((fd) >= 0)			\
+		___err = close((fd));	\
+	fd = -1;			\
+	___err; })
+#endif
+
+#ifdef HAVE_LIBELF_MMAP_SUPPORT
+# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ_MMAP
+#else
+# define LIBBPF_ELF_C_READ_MMAP ELF_C_READ
+#endif
+
+/*
+ * bpf_prog should be a better name but it has been used in
+ * linux/filter.h.
+ */
+struct bpf_program {
+	/* Index in elf obj file, for relocation use. */
+	int idx;
+	char *section_name;
+	struct bpf_insn *insns;
+	size_t insns_cnt;
+	enum bpf_prog_type type;
+
+	struct {
+		int insn_idx;
+		int map_idx;
+	} *reloc_desc;
+	int nr_reloc;
+
+	struct {
+		int nr;
+		int *fds;
+	} instances;
+	bpf_program_prep_t preprocessor;
+
+	struct bpf_object *obj;
+	void *priv;
+	bpf_program_clear_priv_t clear_priv;
+};
+
+struct bpf_map {
+	int fd;
+	char *name;
+	size_t offset;
+	struct bpf_map_def def;
+	void *priv;
+	bpf_map_clear_priv_t clear_priv;
+};
+
+static LIST_HEAD(bpf_objects_list);
+
+struct bpf_object {
+	char license[64];
+	u32 kern_version;
+
+	struct bpf_program *programs;
+	size_t nr_programs;
+	struct bpf_map *maps;
+	size_t nr_maps;
+
+	bool loaded;
+
+	/*
+	 * Information when doing elf related work. Only valid if fd
+	 * is valid.
+	 */
+	struct {
+		int fd;
+		void *obj_buf;
+		size_t obj_buf_sz;
+		Elf *elf;
+		GElf_Ehdr ehdr;
+		Elf_Data *symbols;
+		size_t strtabidx;
+		struct {
+			GElf_Shdr shdr;
+			Elf_Data *data;
+		} *reloc;
+		int nr_reloc;
+		int maps_shndx;
+	} efile;
+	/*
+	 * All loaded bpf_object is linked in a list, which is
+	 * hidden to caller. bpf_objects__<func> handlers deal with
+	 * all objects.
+	 */
+	struct list_head list;
+
+	void *priv;
+	bpf_object_clear_priv_t clear_priv;
+
+	char path[];
+};
+#define obj_elf_valid(o)	((o)->efile.elf)
+
+static void bpf_program__unload(struct bpf_program *prog)
+{
+	int i;
+
+	if (!prog)
+		return;
+
+	/*
+	 * If the object is opened but the program was never loaded,
+	 * it is possible that prog->instances.nr == -1.
+	 */
+	if (prog->instances.nr > 0) {
+		for (i = 0; i < prog->instances.nr; i++)
+			zclose(prog->instances.fds[i]);
+	} else if (prog->instances.nr != -1) {
+		pr_warning("Internal error: instances.nr is %d\n",
+			   prog->instances.nr);
+	}
+
+	prog->instances.nr = -1;
+	zfree(&prog->instances.fds);
+}
+
+static void bpf_program__exit(struct bpf_program *prog)
+{
+	if (!prog)
+		return;
+
+	if (prog->clear_priv)
+		prog->clear_priv(prog, prog->priv);
+
+	prog->priv = NULL;
+	prog->clear_priv = NULL;
+
+	bpf_program__unload(prog);
+	zfree(&prog->section_name);
+	zfree(&prog->insns);
+	zfree(&prog->reloc_desc);
+
+	prog->nr_reloc = 0;
+	prog->insns_cnt = 0;
+	prog->idx = -1;
+}
+
+static int
+bpf_program__init(void *data, size_t size, char *name, int idx,
+		    struct bpf_program *prog)
+{
+	if (size < sizeof(struct bpf_insn)) {
+		pr_warning("corrupted section '%s'\n", name);
+		return -EINVAL;
+	}
+
+	bzero(prog, sizeof(*prog));
+
+	prog->section_name = strdup(name);
+	if (!prog->section_name) {
+		pr_warning("failed to alloc name for prog %s\n",
+			   name);
+		goto errout;
+	}
+
+	prog->insns = malloc(size);
+	if (!prog->insns) {
+		pr_warning("failed to alloc insns for %s\n", name);
+		goto errout;
+	}
+	prog->insns_cnt = size / sizeof(struct bpf_insn);
+	memcpy(prog->insns, data,
+	       prog->insns_cnt * sizeof(struct bpf_insn));
+	prog->idx = idx;
+	prog->instances.fds = NULL;
+	prog->instances.nr = -1;
+	prog->type = BPF_PROG_TYPE_KPROBE;
+
+	return 0;
+errout:
+	bpf_program__exit(prog);
+	return -ENOMEM;
+}
+
+static int
+bpf_object__add_program(struct bpf_object *obj, void *data, size_t size,
+			char *name, int idx)
+{
+	struct bpf_program prog, *progs;
+	int nr_progs, err;
+
+	err = bpf_program__init(data, size, name, idx, &prog);
+	if (err)
+		return err;
+
+	progs = obj->programs;
+	nr_progs = obj->nr_programs;
+
+	progs = realloc(progs, sizeof(progs[0]) * (nr_progs + 1));
+	if (!progs) {
+		/*
+		 * In this case the original obj->programs
+		 * is still valid, so don't need special treat for
+		 * bpf_close_object().
+		 */
+		pr_warning("failed to alloc a new program '%s'\n",
+			   name);
+		bpf_program__exit(&prog);
+		return -ENOMEM;
+	}
+
+	pr_debug("found program %s\n", prog.section_name);
+	obj->programs = progs;
+	obj->nr_programs = nr_progs + 1;
+	prog.obj = obj;
+	progs[nr_progs] = prog;
+	return 0;
+}
+
+static struct bpf_object *bpf_object__new(const char *path,
+					  void *obj_buf,
+					  size_t obj_buf_sz)
+{
+	struct bpf_object *obj;
+
+	obj = calloc(1, sizeof(struct bpf_object) + strlen(path) + 1);
+	if (!obj) {
+		pr_warning("alloc memory failed for %s\n", path);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	strcpy(obj->path, path);
+	obj->efile.fd = -1;
+
+	/*
+	 * Caller of this function should also calls
+	 * bpf_object__elf_finish() after data collection to return
+	 * obj_buf to user. If not, we should duplicate the buffer to
+	 * avoid user freeing them before elf finish.
+	 */
+	obj->efile.obj_buf = obj_buf;
+	obj->efile.obj_buf_sz = obj_buf_sz;
+	obj->efile.maps_shndx = -1;
+
+	obj->loaded = false;
+
+	INIT_LIST_HEAD(&obj->list);
+	list_add(&obj->list, &bpf_objects_list);
+	return obj;
+}
+
+static void bpf_object__elf_finish(struct bpf_object *obj)
+{
+	if (!obj_elf_valid(obj))
+		return;
+
+	if (obj->efile.elf) {
+		elf_end(obj->efile.elf);
+		obj->efile.elf = NULL;
+	}
+	obj->efile.symbols = NULL;
+
+	zfree(&obj->efile.reloc);
+	obj->efile.nr_reloc = 0;
+	zclose(obj->efile.fd);
+	obj->efile.obj_buf = NULL;
+	obj->efile.obj_buf_sz = 0;
+}
+
+static int bpf_object__elf_init(struct bpf_object *obj)
+{
+	int err = 0;
+	GElf_Ehdr *ep;
+
+	if (obj_elf_valid(obj)) {
+		pr_warning("elf init: internal error\n");
+		return -LIBBPF_ERRNO__LIBELF;
+	}
+
+	if (obj->efile.obj_buf_sz > 0) {
+		/*
+		 * obj_buf should have been validated by
+		 * bpf_object__open_buffer().
+		 */
+		obj->efile.elf = elf_memory(obj->efile.obj_buf,
+					    obj->efile.obj_buf_sz);
+	} else {
+		obj->efile.fd = open(obj->path, O_RDONLY);
+		if (obj->efile.fd < 0) {
+			pr_warning("failed to open %s: %s\n", obj->path,
+					strerror(errno));
+			return -errno;
+		}
+
+		obj->efile.elf = elf_begin(obj->efile.fd,
+				LIBBPF_ELF_C_READ_MMAP,
+				NULL);
+	}
+
+	if (!obj->efile.elf) {
+		pr_warning("failed to open %s as ELF file\n",
+				obj->path);
+		err = -LIBBPF_ERRNO__LIBELF;
+		goto errout;
+	}
+
+	if (!gelf_getehdr(obj->efile.elf, &obj->efile.ehdr)) {
+		pr_warning("failed to get EHDR from %s\n",
+				obj->path);
+		err = -LIBBPF_ERRNO__FORMAT;
+		goto errout;
+	}
+	ep = &obj->efile.ehdr;
+
+	/* Old LLVM set e_machine to EM_NONE */
+	if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
+		pr_warning("%s is not an eBPF object file\n",
+			obj->path);
+		err = -LIBBPF_ERRNO__FORMAT;
+		goto errout;
+	}
+
+	return 0;
+errout:
+	bpf_object__elf_finish(obj);
+	return err;
+}
+
+static int
+bpf_object__check_endianness(struct bpf_object *obj)
+{
+	static unsigned int const endian = 1;
+
+	switch (obj->efile.ehdr.e_ident[EI_DATA]) {
+	case ELFDATA2LSB:
+		/* We are big endian, BPF obj is little endian. */
+		if (*(unsigned char const *)&endian != 1)
+			goto mismatch;
+		break;
+
+	case ELFDATA2MSB:
+		/* We are little endian, BPF obj is big endian. */
+		if (*(unsigned char const *)&endian != 0)
+			goto mismatch;
+		break;
+	default:
+		return -LIBBPF_ERRNO__ENDIAN;
+	}
+
+	return 0;
+
+mismatch:
+	pr_warning("Error: endianness mismatch.\n");
+	return -LIBBPF_ERRNO__ENDIAN;
+}
+
+static int
+bpf_object__init_license(struct bpf_object *obj,
+			 void *data, size_t size)
+{
+	memcpy(obj->license, data,
+	       min(size, sizeof(obj->license) - 1));
+	pr_debug("license of %s is %s\n", obj->path, obj->license);
+	return 0;
+}
+
+static int
+bpf_object__init_kversion(struct bpf_object *obj,
+			  void *data, size_t size)
+{
+	u32 kver;
+
+	if (size != sizeof(kver)) {
+		pr_warning("invalid kver section in %s\n", obj->path);
+		return -LIBBPF_ERRNO__FORMAT;
+	}
+	memcpy(&kver, data, sizeof(kver));
+	obj->kern_version = kver;
+	pr_debug("kernel version of %s is %x\n", obj->path,
+		 obj->kern_version);
+	return 0;
+}
+
+static int
+bpf_object__validate_maps(struct bpf_object *obj)
+{
+	int i;
+
+	/*
+	 * If there's only 1 map, the only error case should have been
+	 * catched in bpf_object__init_maps().
+	 */
+	if (!obj->maps || !obj->nr_maps || (obj->nr_maps == 1))
+		return 0;
+
+	for (i = 1; i < obj->nr_maps; i++) {
+		const struct bpf_map *a = &obj->maps[i - 1];
+		const struct bpf_map *b = &obj->maps[i];
+
+		if (b->offset - a->offset < sizeof(struct bpf_map_def)) {
+			pr_warning("corrupted map section in %s: map \"%s\" too small\n",
+				   obj->path, a->name);
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+static int compare_bpf_map(const void *_a, const void *_b)
+{
+	const struct bpf_map *a = _a;
+	const struct bpf_map *b = _b;
+
+	return a->offset - b->offset;
+}
+
+static int
+bpf_object__init_maps(struct bpf_object *obj)
+{
+	int i, map_idx, nr_maps = 0;
+	Elf_Scn *scn;
+	Elf_Data *data;
+	Elf_Data *symbols = obj->efile.symbols;
+
+	if (obj->efile.maps_shndx < 0)
+		return -EINVAL;
+	if (!symbols)
+		return -EINVAL;
+
+	scn = elf_getscn(obj->efile.elf, obj->efile.maps_shndx);
+	if (scn)
+		data = elf_getdata(scn, NULL);
+	if (!scn || !data) {
+		pr_warning("failed to get Elf_Data from map section %d\n",
+			   obj->efile.maps_shndx);
+		return -EINVAL;
+	}
+
+	/*
+	 * Count number of maps. Each map has a name.
+	 * Array of maps is not supported: only the first element is
+	 * considered.
+	 *
+	 * TODO: Detect array of map and report error.
+	 */
+	for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
+		GElf_Sym sym;
+
+		if (!gelf_getsym(symbols, i, &sym))
+			continue;
+		if (sym.st_shndx != obj->efile.maps_shndx)
+			continue;
+		nr_maps++;
+	}
+
+	/* Alloc obj->maps and fill nr_maps. */
+	pr_debug("maps in %s: %d maps in %zd bytes\n", obj->path,
+		 nr_maps, data->d_size);
+
+	if (!nr_maps)
+		return 0;
+
+	obj->maps = calloc(nr_maps, sizeof(obj->maps[0]));
+	if (!obj->maps) {
+		pr_warning("alloc maps for object failed\n");
+		return -ENOMEM;
+	}
+	obj->nr_maps = nr_maps;
+
+	/*
+	 * fill all fd with -1 so won't close incorrect
+	 * fd (fd=0 is stdin) when failure (zclose won't close
+	 * negative fd)).
+	 */
+	for (i = 0; i < nr_maps; i++)
+		obj->maps[i].fd = -1;
+
+	/*
+	 * Fill obj->maps using data in "maps" section.
+	 */
+	for (i = 0, map_idx = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
+		GElf_Sym sym;
+		const char *map_name;
+		struct bpf_map_def *def;
+
+		if (!gelf_getsym(symbols, i, &sym))
+			continue;
+		if (sym.st_shndx != obj->efile.maps_shndx)
+			continue;
+
+		map_name = elf_strptr(obj->efile.elf,
+				      obj->efile.strtabidx,
+				      sym.st_name);
+		obj->maps[map_idx].offset = sym.st_value;
+		if (sym.st_value + sizeof(struct bpf_map_def) > data->d_size) {
+			pr_warning("corrupted maps section in %s: last map \"%s\" too small\n",
+				   obj->path, map_name);
+			return -EINVAL;
+		}
+
+		obj->maps[map_idx].name = strdup(map_name);
+		if (!obj->maps[map_idx].name) {
+			pr_warning("failed to alloc map name\n");
+			return -ENOMEM;
+		}
+		pr_debug("map %d is \"%s\"\n", map_idx,
+			 obj->maps[map_idx].name);
+		def = (struct bpf_map_def *)(data->d_buf + sym.st_value);
+		obj->maps[map_idx].def = *def;
+		map_idx++;
+	}
+
+	qsort(obj->maps, obj->nr_maps, sizeof(obj->maps[0]), compare_bpf_map);
+	return bpf_object__validate_maps(obj);
+}
+
+static bool section_have_execinstr(struct bpf_object *obj, int idx)
+{
+	Elf_Scn *scn;
+	GElf_Shdr sh;
+
+	scn = elf_getscn(obj->efile.elf, idx);
+	if (!scn)
+		return false;
+
+	if (gelf_getshdr(scn, &sh) != &sh)
+		return false;
+
+	if (sh.sh_flags & SHF_EXECINSTR)
+		return true;
+
+	return false;
+}
+
+static int bpf_object__elf_collect(struct bpf_object *obj)
+{
+	Elf *elf = obj->efile.elf;
+	GElf_Ehdr *ep = &obj->efile.ehdr;
+	Elf_Scn *scn = NULL;
+	int idx = 0, err = 0;
+
+	/* Elf is corrupted/truncated, avoid calling elf_strptr. */
+	if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL)) {
+		pr_warning("failed to get e_shstrndx from %s\n",
+			   obj->path);
+		return -LIBBPF_ERRNO__FORMAT;
+	}
+
+	while ((scn = elf_nextscn(elf, scn)) != NULL) {
+		char *name;
+		GElf_Shdr sh;
+		Elf_Data *data;
+
+		idx++;
+		if (gelf_getshdr(scn, &sh) != &sh) {
+			pr_warning("failed to get section header from %s\n",
+				   obj->path);
+			err = -LIBBPF_ERRNO__FORMAT;
+			goto out;
+		}
+
+		name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
+		if (!name) {
+			pr_warning("failed to get section name from %s\n",
+				   obj->path);
+			err = -LIBBPF_ERRNO__FORMAT;
+			goto out;
+		}
+
+		data = elf_getdata(scn, 0);
+		if (!data) {
+			pr_warning("failed to get section data from %s(%s)\n",
+				   name, obj->path);
+			err = -LIBBPF_ERRNO__FORMAT;
+			goto out;
+		}
+		pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
+			 name, (unsigned long)data->d_size,
+			 (int)sh.sh_link, (unsigned long)sh.sh_flags,
+			 (int)sh.sh_type);
+
+		if (strcmp(name, "license") == 0)
+			err = bpf_object__init_license(obj,
+						       data->d_buf,
+						       data->d_size);
+		else if (strcmp(name, "version") == 0)
+			err = bpf_object__init_kversion(obj,
+							data->d_buf,
+							data->d_size);
+		else if (strcmp(name, "maps") == 0)
+			obj->efile.maps_shndx = idx;
+		else if (sh.sh_type == SHT_SYMTAB) {
+			if (obj->efile.symbols) {
+				pr_warning("bpf: multiple SYMTAB in %s\n",
+					   obj->path);
+				err = -LIBBPF_ERRNO__FORMAT;
+			} else {
+				obj->efile.symbols = data;
+				obj->efile.strtabidx = sh.sh_link;
+			}
+		} else if ((sh.sh_type == SHT_PROGBITS) &&
+			   (sh.sh_flags & SHF_EXECINSTR) &&
+			   (data->d_size > 0)) {
+			err = bpf_object__add_program(obj, data->d_buf,
+						      data->d_size, name, idx);
+			if (err) {
+				char errmsg[STRERR_BUFSIZE];
+
+				strerror_r(-err, errmsg, sizeof(errmsg));
+				pr_warning("failed to alloc program %s (%s): %s",
+					   name, obj->path, errmsg);
+			}
+		} else if (sh.sh_type == SHT_REL) {
+			void *reloc = obj->efile.reloc;
+			int nr_reloc = obj->efile.nr_reloc + 1;
+			int sec = sh.sh_info; /* points to other section */
+
+			/* Only do relo for section with exec instructions */
+			if (!section_have_execinstr(obj, sec)) {
+				pr_debug("skip relo %s(%d) for section(%d)\n",
+					 name, idx, sec);
+				continue;
+			}
+
+			reloc = realloc(reloc,
+					sizeof(*obj->efile.reloc) * nr_reloc);
+			if (!reloc) {
+				pr_warning("realloc failed\n");
+				err = -ENOMEM;
+			} else {
+				int n = nr_reloc - 1;
+
+				obj->efile.reloc = reloc;
+				obj->efile.nr_reloc = nr_reloc;
+
+				obj->efile.reloc[n].shdr = sh;
+				obj->efile.reloc[n].data = data;
+			}
+		}
+		if (err)
+			goto out;
+	}
+
+	if (!obj->efile.strtabidx || obj->efile.strtabidx >= idx) {
+		pr_warning("Corrupted ELF file: index of strtab invalid\n");
+		return LIBBPF_ERRNO__FORMAT;
+	}
+	if (obj->efile.maps_shndx >= 0)
+		err = bpf_object__init_maps(obj);
+out:
+	return err;
+}
+
+static struct bpf_program *
+bpf_object__find_prog_by_idx(struct bpf_object *obj, int idx)
+{
+	struct bpf_program *prog;
+	size_t i;
+
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+		if (prog->idx == idx)
+			return prog;
+	}
+	return NULL;
+}
+
+static int
+bpf_program__collect_reloc(struct bpf_program *prog,
+			   size_t nr_maps, GElf_Shdr *shdr,
+			   Elf_Data *data, Elf_Data *symbols,
+			   int maps_shndx, struct bpf_map *maps)
+{
+	int i, nrels;
+
+	pr_debug("collecting relocating info for: '%s'\n",
+		 prog->section_name);
+	nrels = shdr->sh_size / shdr->sh_entsize;
+
+	prog->reloc_desc = malloc(sizeof(*prog->reloc_desc) * nrels);
+	if (!prog->reloc_desc) {
+		pr_warning("failed to alloc memory in relocation\n");
+		return -ENOMEM;
+	}
+	prog->nr_reloc = nrels;
+
+	for (i = 0; i < nrels; i++) {
+		GElf_Sym sym;
+		GElf_Rel rel;
+		unsigned int insn_idx;
+		struct bpf_insn *insns = prog->insns;
+		size_t map_idx;
+
+		if (!gelf_getrel(data, i, &rel)) {
+			pr_warning("relocation: failed to get %d reloc\n", i);
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		if (!gelf_getsym(symbols,
+				 GELF_R_SYM(rel.r_info),
+				 &sym)) {
+			pr_warning("relocation: symbol %"PRIx64" not found\n",
+				   GELF_R_SYM(rel.r_info));
+			return -LIBBPF_ERRNO__FORMAT;
+		}
+
+		if (sym.st_shndx != maps_shndx) {
+			pr_warning("Program '%s' contains non-map related relo data pointing to section %u\n",
+				   prog->section_name, sym.st_shndx);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+
+		insn_idx = rel.r_offset / sizeof(struct bpf_insn);
+		pr_debug("relocation: insn_idx=%u\n", insn_idx);
+
+		if (insns[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
+			pr_warning("bpf: relocation: invalid relo for insns[%d].code 0x%x\n",
+				   insn_idx, insns[insn_idx].code);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+
+		/* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
+		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+			if (maps[map_idx].offset == sym.st_value) {
+				pr_debug("relocation: find map %zd (%s) for insn %u\n",
+					 map_idx, maps[map_idx].name, insn_idx);
+				break;
+			}
+		}
+
+		if (map_idx >= nr_maps) {
+			pr_warning("bpf relocation: map_idx %d large than %d\n",
+				   (int)map_idx, (int)nr_maps - 1);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+
+		prog->reloc_desc[i].insn_idx = insn_idx;
+		prog->reloc_desc[i].map_idx = map_idx;
+	}
+	return 0;
+}
+
+static int
+bpf_object__create_maps(struct bpf_object *obj)
+{
+	unsigned int i;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		struct bpf_map_def *def = &obj->maps[i].def;
+		int *pfd = &obj->maps[i].fd;
+
+		*pfd = bpf_create_map(def->type,
+				      def->key_size,
+				      def->value_size,
+				      def->max_entries,
+				      0);
+		if (*pfd < 0) {
+			size_t j;
+			int err = *pfd;
+
+			pr_warning("failed to create map (name: '%s'): %s\n",
+				   obj->maps[i].name,
+				   strerror(errno));
+			for (j = 0; j < i; j++)
+				zclose(obj->maps[j].fd);
+			return err;
+		}
+		pr_debug("create map %s: fd=%d\n", obj->maps[i].name, *pfd);
+	}
+
+	return 0;
+}
+
+static int
+bpf_program__relocate(struct bpf_program *prog, struct bpf_object *obj)
+{
+	int i;
+
+	if (!prog || !prog->reloc_desc)
+		return 0;
+
+	for (i = 0; i < prog->nr_reloc; i++) {
+		int insn_idx, map_idx;
+		struct bpf_insn *insns = prog->insns;
+
+		insn_idx = prog->reloc_desc[i].insn_idx;
+		map_idx = prog->reloc_desc[i].map_idx;
+
+		if (insn_idx >= (int)prog->insns_cnt) {
+			pr_warning("relocation out of range: '%s'\n",
+				   prog->section_name);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+		insns[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;
+		insns[insn_idx].imm = obj->maps[map_idx].fd;
+	}
+
+	zfree(&prog->reloc_desc);
+	prog->nr_reloc = 0;
+	return 0;
+}
+
+
+static int
+bpf_object__relocate(struct bpf_object *obj)
+{
+	struct bpf_program *prog;
+	size_t i;
+	int err;
+
+	for (i = 0; i < obj->nr_programs; i++) {
+		prog = &obj->programs[i];
+
+		err = bpf_program__relocate(prog, obj);
+		if (err) {
+			pr_warning("failed to relocate '%s'\n",
+				   prog->section_name);
+			return err;
+		}
+	}
+	return 0;
+}
+
+static int bpf_object__collect_reloc(struct bpf_object *obj)
+{
+	int i, err;
+
+	if (!obj_elf_valid(obj)) {
+		pr_warning("Internal error: elf object is closed\n");
+		return -LIBBPF_ERRNO__INTERNAL;
+	}
+
+	for (i = 0; i < obj->efile.nr_reloc; i++) {
+		GElf_Shdr *shdr = &obj->efile.reloc[i].shdr;
+		Elf_Data *data = obj->efile.reloc[i].data;
+		int idx = shdr->sh_info;
+		struct bpf_program *prog;
+		size_t nr_maps = obj->nr_maps;
+
+		if (shdr->sh_type != SHT_REL) {
+			pr_warning("internal error at %d\n", __LINE__);
+			return -LIBBPF_ERRNO__INTERNAL;
+		}
+
+		prog = bpf_object__find_prog_by_idx(obj, idx);
+		if (!prog) {
+			pr_warning("relocation failed: no %d section\n",
+				   idx);
+			return -LIBBPF_ERRNO__RELOC;
+		}
+
+		err = bpf_program__collect_reloc(prog, nr_maps,
+						 shdr, data,
+						 obj->efile.symbols,
+						 obj->efile.maps_shndx,
+						 obj->maps);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int
+load_program(enum bpf_prog_type type, struct bpf_insn *insns,
+	     int insns_cnt, char *license, u32 kern_version, int *pfd)
+{
+	int ret;
+	char *log_buf;
+
+	if (!insns || !insns_cnt)
+		return -EINVAL;
+
+	log_buf = malloc(BPF_LOG_BUF_SIZE);
+	if (!log_buf)
+		pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
+
+	ret = bpf_load_program(type, insns, insns_cnt, license,
+			       kern_version, log_buf, BPF_LOG_BUF_SIZE);
+
+	if (ret >= 0) {
+		*pfd = ret;
+		ret = 0;
+		goto out;
+	}
+
+	ret = -LIBBPF_ERRNO__LOAD;
+	pr_warning("load bpf program failed: %s\n", strerror(errno));
+
+	if (log_buf && log_buf[0] != '\0') {
+		ret = -LIBBPF_ERRNO__VERIFY;
+		pr_warning("-- BEGIN DUMP LOG ---\n");
+		pr_warning("\n%s\n", log_buf);
+		pr_warning("-- END LOG --\n");
+	} else if (insns_cnt >= BPF_MAXINSNS) {
+		pr_warning("Program too large (%d insns), at most %d insns\n",
+			   insns_cnt, BPF_MAXINSNS);
+		ret = -LIBBPF_ERRNO__PROG2BIG;
+	} else {
+		/* Wrong program type? */
+		if (type != BPF_PROG_TYPE_KPROBE) {
+			int fd;
+
+			fd = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
+					      insns_cnt, license, kern_version,
+					      NULL, 0);
+			if (fd >= 0) {
+				close(fd);
+				ret = -LIBBPF_ERRNO__PROGTYPE;
+				goto out;
+			}
+		}
+
+		if (log_buf)
+			ret = -LIBBPF_ERRNO__KVER;
+	}
+
+out:
+	free(log_buf);
+	return ret;
+}
+
+static int
+bpf_program__load(struct bpf_program *prog,
+		  char *license, u32 kern_version)
+{
+	int err = 0, fd, i;
+
+	if (prog->instances.nr < 0 || !prog->instances.fds) {
+		if (prog->preprocessor) {
+			pr_warning("Internal error: can't load program '%s'\n",
+				   prog->section_name);
+			return -LIBBPF_ERRNO__INTERNAL;
+		}
+
+		prog->instances.fds = malloc(sizeof(int));
+		if (!prog->instances.fds) {
+			pr_warning("Not enough memory for BPF fds\n");
+			return -ENOMEM;
+		}
+		prog->instances.nr = 1;
+		prog->instances.fds[0] = -1;
+	}
+
+	if (!prog->preprocessor) {
+		if (prog->instances.nr != 1) {
+			pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
+				   prog->section_name, prog->instances.nr);
+		}
+		err = load_program(prog->type, prog->insns, prog->insns_cnt,
+				   license, kern_version, &fd);
+		if (!err)
+			prog->instances.fds[0] = fd;
+		goto out;
+	}
+
+	for (i = 0; i < prog->instances.nr; i++) {
+		struct bpf_prog_prep_result result;
+		bpf_program_prep_t preprocessor = prog->preprocessor;
+
+		bzero(&result, sizeof(result));
+		err = preprocessor(prog, i, prog->insns,
+				   prog->insns_cnt, &result);
+		if (err) {
+			pr_warning("Preprocessing the %dth instance of program '%s' failed\n",
+				   i, prog->section_name);
+			goto out;
+		}
+
+		if (!result.new_insn_ptr || !result.new_insn_cnt) {
+			pr_debug("Skip loading the %dth instance of program '%s'\n",
+				 i, prog->section_name);
+			prog->instances.fds[i] = -1;
+			if (result.pfd)
+				*result.pfd = -1;
+			continue;
+		}
+
+		err = load_program(prog->type, result.new_insn_ptr,
+				   result.new_insn_cnt,
+				   license, kern_version, &fd);
+
+		if (err) {
+			pr_warning("Loading the %dth instance of program '%s' failed\n",
+					i, prog->section_name);
+			goto out;
+		}
+
+		if (result.pfd)
+			*result.pfd = fd;
+		prog->instances.fds[i] = fd;
+	}
+out:
+	if (err)
+		pr_warning("failed to load program '%s'\n",
+			   prog->section_name);
+	zfree(&prog->insns);
+	prog->insns_cnt = 0;
+	return err;
+}
+
+static int
+bpf_object__load_progs(struct bpf_object *obj)
+{
+	size_t i;
+	int err;
+
+	for (i = 0; i < obj->nr_programs; i++) {
+		err = bpf_program__load(&obj->programs[i],
+					obj->license,
+					obj->kern_version);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static int bpf_object__validate(struct bpf_object *obj)
+{
+	if (obj->kern_version == 0) {
+		pr_warning("%s doesn't provide kernel version\n",
+			   obj->path);
+		return -LIBBPF_ERRNO__KVERSION;
+	}
+	return 0;
+}
+
+static struct bpf_object *
+__bpf_object__open(const char *path, void *obj_buf, size_t obj_buf_sz)
+{
+	struct bpf_object *obj;
+	int err;
+
+	if (elf_version(EV_CURRENT) == EV_NONE) {
+		pr_warning("failed to init libelf for %s\n", path);
+		return ERR_PTR(-LIBBPF_ERRNO__LIBELF);
+	}
+
+	obj = bpf_object__new(path, obj_buf, obj_buf_sz);
+	if (IS_ERR(obj))
+		return obj;
+
+	CHECK_ERR(bpf_object__elf_init(obj), err, out);
+	CHECK_ERR(bpf_object__check_endianness(obj), err, out);
+	CHECK_ERR(bpf_object__elf_collect(obj), err, out);
+	CHECK_ERR(bpf_object__collect_reloc(obj), err, out);
+	CHECK_ERR(bpf_object__validate(obj), err, out);
+
+	bpf_object__elf_finish(obj);
+	return obj;
+out:
+	bpf_object__close(obj);
+	return ERR_PTR(err);
+}
+
+struct bpf_object *bpf_object__open(const char *path)
+{
+	/* param validation */
+	if (!path)
+		return NULL;
+
+	pr_debug("loading %s\n", path);
+
+	return __bpf_object__open(path, NULL, 0);
+}
+
+struct bpf_object *bpf_object__open_buffer(void *obj_buf,
+					   size_t obj_buf_sz,
+					   const char *name)
+{
+	char tmp_name[64];
+
+	/* param validation */
+	if (!obj_buf || obj_buf_sz <= 0)
+		return NULL;
+
+	if (!name) {
+		snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
+			 (unsigned long)obj_buf,
+			 (unsigned long)obj_buf_sz);
+		tmp_name[sizeof(tmp_name) - 1] = '\0';
+		name = tmp_name;
+	}
+	pr_debug("loading object '%s' from buffer\n",
+		 name);
+
+	return __bpf_object__open(name, obj_buf, obj_buf_sz);
+}
+
+int bpf_object__unload(struct bpf_object *obj)
+{
+	size_t i;
+
+	if (!obj)
+		return -EINVAL;
+
+	for (i = 0; i < obj->nr_maps; i++)
+		zclose(obj->maps[i].fd);
+
+	for (i = 0; i < obj->nr_programs; i++)
+		bpf_program__unload(&obj->programs[i]);
+
+	return 0;
+}
+
+int bpf_object__load(struct bpf_object *obj)
+{
+	int err;
+
+	if (!obj)
+		return -EINVAL;
+
+	if (obj->loaded) {
+		pr_warning("object should not be loaded twice\n");
+		return -EINVAL;
+	}
+
+	obj->loaded = true;
+
+	CHECK_ERR(bpf_object__create_maps(obj), err, out);
+	CHECK_ERR(bpf_object__relocate(obj), err, out);
+	CHECK_ERR(bpf_object__load_progs(obj), err, out);
+
+	return 0;
+out:
+	bpf_object__unload(obj);
+	pr_warning("failed to load object '%s'\n", obj->path);
+	return err;
+}
+
+static int check_path(const char *path)
+{
+	struct statfs st_fs;
+	char *dname, *dir;
+	int err = 0;
+
+	if (path == NULL)
+		return -EINVAL;
+
+	dname = strdup(path);
+	if (dname == NULL)
+		return -ENOMEM;
+
+	dir = dirname(dname);
+	if (statfs(dir, &st_fs)) {
+		pr_warning("failed to statfs %s: %s\n", dir, strerror(errno));
+		err = -errno;
+	}
+	free(dname);
+
+	if (!err && st_fs.f_type != BPF_FS_MAGIC) {
+		pr_warning("specified path %s is not on BPF FS\n", path);
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+int bpf_program__pin_instance(struct bpf_program *prog, const char *path,
+			      int instance)
+{
+	int err;
+
+	err = check_path(path);
+	if (err)
+		return err;
+
+	if (prog == NULL) {
+		pr_warning("invalid program pointer\n");
+		return -EINVAL;
+	}
+
+	if (instance < 0 || instance >= prog->instances.nr) {
+		pr_warning("invalid prog instance %d of prog %s (max %d)\n",
+			   instance, prog->section_name, prog->instances.nr);
+		return -EINVAL;
+	}
+
+	if (bpf_obj_pin(prog->instances.fds[instance], path)) {
+		pr_warning("failed to pin program: %s\n", strerror(errno));
+		return -errno;
+	}
+	pr_debug("pinned program '%s'\n", path);
+
+	return 0;
+}
+
+static int make_dir(const char *path)
+{
+	int err = 0;
+
+	if (mkdir(path, 0700) && errno != EEXIST)
+		err = -errno;
+
+	if (err)
+		pr_warning("failed to mkdir %s: %s\n", path, strerror(-err));
+	return err;
+}
+
+int bpf_program__pin(struct bpf_program *prog, const char *path)
+{
+	int i, err;
+
+	err = check_path(path);
+	if (err)
+		return err;
+
+	if (prog == NULL) {
+		pr_warning("invalid program pointer\n");
+		return -EINVAL;
+	}
+
+	if (prog->instances.nr <= 0) {
+		pr_warning("no instances of prog %s to pin\n",
+			   prog->section_name);
+		return -EINVAL;
+	}
+
+	err = make_dir(path);
+	if (err)
+		return err;
+
+	for (i = 0; i < prog->instances.nr; i++) {
+		char buf[PATH_MAX];
+		int len;
+
+		len = snprintf(buf, PATH_MAX, "%s/%d", path, i);
+		if (len < 0)
+			return -EINVAL;
+		else if (len >= PATH_MAX)
+			return -ENAMETOOLONG;
+
+		err = bpf_program__pin_instance(prog, buf, i);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+int bpf_map__pin(struct bpf_map *map, const char *path)
+{
+	int err;
+
+	err = check_path(path);
+	if (err)
+		return err;
+
+	if (map == NULL) {
+		pr_warning("invalid map pointer\n");
+		return -EINVAL;
+	}
+
+	if (bpf_obj_pin(map->fd, path)) {
+		pr_warning("failed to pin map: %s\n", strerror(errno));
+		return -errno;
+	}
+
+	pr_debug("pinned map '%s'\n", path);
+	return 0;
+}
+
+int bpf_object__pin(struct bpf_object *obj, const char *path)
+{
+	struct bpf_program *prog;
+	struct bpf_map *map;
+	int err;
+
+	if (!obj)
+		return -ENOENT;
+
+	if (!obj->loaded) {
+		pr_warning("object not yet loaded; load it first\n");
+		return -ENOENT;
+	}
+
+	err = make_dir(path);
+	if (err)
+		return err;
+
+	bpf_map__for_each(map, obj) {
+		char buf[PATH_MAX];
+		int len;
+
+		len = snprintf(buf, PATH_MAX, "%s/%s", path,
+			       bpf_map__name(map));
+		if (len < 0)
+			return -EINVAL;
+		else if (len >= PATH_MAX)
+			return -ENAMETOOLONG;
+
+		err = bpf_map__pin(map, buf);
+		if (err)
+			return err;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		char buf[PATH_MAX];
+		int len;
+
+		len = snprintf(buf, PATH_MAX, "%s/%s", path,
+			       prog->section_name);
+		if (len < 0)
+			return -EINVAL;
+		else if (len >= PATH_MAX)
+			return -ENAMETOOLONG;
+
+		err = bpf_program__pin(prog, buf);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+void bpf_object__close(struct bpf_object *obj)
+{
+	size_t i;
+
+	if (!obj)
+		return;
+
+	if (obj->clear_priv)
+		obj->clear_priv(obj, obj->priv);
+
+	bpf_object__elf_finish(obj);
+	bpf_object__unload(obj);
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		zfree(&obj->maps[i].name);
+		if (obj->maps[i].clear_priv)
+			obj->maps[i].clear_priv(&obj->maps[i],
+						obj->maps[i].priv);
+		obj->maps[i].priv = NULL;
+		obj->maps[i].clear_priv = NULL;
+	}
+	zfree(&obj->maps);
+	obj->nr_maps = 0;
+
+	if (obj->programs && obj->nr_programs) {
+		for (i = 0; i < obj->nr_programs; i++)
+			bpf_program__exit(&obj->programs[i]);
+	}
+	zfree(&obj->programs);
+
+	list_del(&obj->list);
+	free(obj);
+}
+
+struct bpf_object *
+bpf_object__next(struct bpf_object *prev)
+{
+	struct bpf_object *next;
+
+	if (!prev)
+		next = list_first_entry(&bpf_objects_list,
+					struct bpf_object,
+					list);
+	else
+		next = list_next_entry(prev, list);
+
+	/* Empty list is noticed here so don't need checking on entry. */
+	if (&next->list == &bpf_objects_list)
+		return NULL;
+
+	return next;
+}
+
+const char *bpf_object__name(struct bpf_object *obj)
+{
+	return obj ? obj->path : ERR_PTR(-EINVAL);
+}
+
+unsigned int bpf_object__kversion(struct bpf_object *obj)
+{
+	return obj ? obj->kern_version : 0;
+}
+
+int bpf_object__set_priv(struct bpf_object *obj, void *priv,
+			 bpf_object_clear_priv_t clear_priv)
+{
+	if (obj->priv && obj->clear_priv)
+		obj->clear_priv(obj, obj->priv);
+
+	obj->priv = priv;
+	obj->clear_priv = clear_priv;
+	return 0;
+}
+
+void *bpf_object__priv(struct bpf_object *obj)
+{
+	return obj ? obj->priv : ERR_PTR(-EINVAL);
+}
+
+struct bpf_program *
+bpf_program__next(struct bpf_program *prev, struct bpf_object *obj)
+{
+	size_t idx;
+
+	if (!obj->programs)
+		return NULL;
+	/* First handler */
+	if (prev == NULL)
+		return &obj->programs[0];
+
+	if (prev->obj != obj) {
+		pr_warning("error: program handler doesn't match object\n");
+		return NULL;
+	}
+
+	idx = (prev - obj->programs) + 1;
+	if (idx >= obj->nr_programs)
+		return NULL;
+	return &obj->programs[idx];
+}
+
+int bpf_program__set_priv(struct bpf_program *prog, void *priv,
+			  bpf_program_clear_priv_t clear_priv)
+{
+	if (prog->priv && prog->clear_priv)
+		prog->clear_priv(prog, prog->priv);
+
+	prog->priv = priv;
+	prog->clear_priv = clear_priv;
+	return 0;
+}
+
+void *bpf_program__priv(struct bpf_program *prog)
+{
+	return prog ? prog->priv : ERR_PTR(-EINVAL);
+}
+
+const char *bpf_program__title(struct bpf_program *prog, bool needs_copy)
+{
+	const char *title;
+
+	title = prog->section_name;
+	if (needs_copy) {
+		title = strdup(title);
+		if (!title) {
+			pr_warning("failed to strdup program title\n");
+			return ERR_PTR(-ENOMEM);
+		}
+	}
+
+	return title;
+}
+
+int bpf_program__fd(struct bpf_program *prog)
+{
+	return bpf_program__nth_fd(prog, 0);
+}
+
+int bpf_program__set_prep(struct bpf_program *prog, int nr_instances,
+			  bpf_program_prep_t prep)
+{
+	int *instances_fds;
+
+	if (nr_instances <= 0 || !prep)
+		return -EINVAL;
+
+	if (prog->instances.nr > 0 || prog->instances.fds) {
+		pr_warning("Can't set pre-processor after loading\n");
+		return -EINVAL;
+	}
+
+	instances_fds = malloc(sizeof(int) * nr_instances);
+	if (!instances_fds) {
+		pr_warning("alloc memory failed for fds\n");
+		return -ENOMEM;
+	}
+
+	/* fill all fd with -1 */
+	memset(instances_fds, -1, sizeof(int) * nr_instances);
+
+	prog->instances.nr = nr_instances;
+	prog->instances.fds = instances_fds;
+	prog->preprocessor = prep;
+	return 0;
+}
+
+int bpf_program__nth_fd(struct bpf_program *prog, int n)
+{
+	int fd;
+
+	if (n >= prog->instances.nr || n < 0) {
+		pr_warning("Can't get the %dth fd from program %s: only %d instances\n",
+			   n, prog->section_name, prog->instances.nr);
+		return -EINVAL;
+	}
+
+	fd = prog->instances.fds[n];
+	if (fd < 0) {
+		pr_warning("%dth instance of program '%s' is invalid\n",
+			   n, prog->section_name);
+		return -ENOENT;
+	}
+
+	return fd;
+}
+
+void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
+{
+	prog->type = type;
+}
+
+static bool bpf_program__is_type(struct bpf_program *prog,
+				 enum bpf_prog_type type)
+{
+	return prog ? (prog->type == type) : false;
+}
+
+#define BPF_PROG_TYPE_FNS(NAME, TYPE)			\
+int bpf_program__set_##NAME(struct bpf_program *prog)	\
+{							\
+	if (!prog)					\
+		return -EINVAL;				\
+	bpf_program__set_type(prog, TYPE);		\
+	return 0;					\
+}							\
+							\
+bool bpf_program__is_##NAME(struct bpf_program *prog)	\
+{							\
+	return bpf_program__is_type(prog, TYPE);	\
+}							\
+
+BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
+BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
+BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
+BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
+BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
+BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
+BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
+
+int bpf_map__fd(struct bpf_map *map)
+{
+	return map ? map->fd : -EINVAL;
+}
+
+const struct bpf_map_def *bpf_map__def(struct bpf_map *map)
+{
+	return map ? &map->def : ERR_PTR(-EINVAL);
+}
+
+const char *bpf_map__name(struct bpf_map *map)
+{
+	return map ? map->name : NULL;
+}
+
+int bpf_map__set_priv(struct bpf_map *map, void *priv,
+		     bpf_map_clear_priv_t clear_priv)
+{
+	if (!map)
+		return -EINVAL;
+
+	if (map->priv) {
+		if (map->clear_priv)
+			map->clear_priv(map, map->priv);
+	}
+
+	map->priv = priv;
+	map->clear_priv = clear_priv;
+	return 0;
+}
+
+void *bpf_map__priv(struct bpf_map *map)
+{
+	return map ? map->priv : ERR_PTR(-EINVAL);
+}
+
+struct bpf_map *
+bpf_map__next(struct bpf_map *prev, struct bpf_object *obj)
+{
+	size_t idx;
+	struct bpf_map *s, *e;
+
+	if (!obj || !obj->maps)
+		return NULL;
+
+	s = obj->maps;
+	e = obj->maps + obj->nr_maps;
+
+	if (prev == NULL)
+		return s;
+
+	if ((prev < s) || (prev >= e)) {
+		pr_warning("error in %s: map handler doesn't belong to object\n",
+			   __func__);
+		return NULL;
+	}
+
+	idx = (prev - obj->maps) + 1;
+	if (idx >= obj->nr_maps)
+		return NULL;
+	return &obj->maps[idx];
+}
+
+struct bpf_map *
+bpf_object__find_map_by_name(struct bpf_object *obj, const char *name)
+{
+	struct bpf_map *pos;
+
+	bpf_map__for_each(pos, obj) {
+		if (pos->name && !strcmp(pos->name, name))
+			return pos;
+	}
+	return NULL;
+}
+
+struct bpf_map *
+bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
+{
+	int i;
+
+	for (i = 0; i < obj->nr_maps; i++) {
+		if (obj->maps[i].offset == offset)
+			return &obj->maps[i];
+	}
+	return ERR_PTR(-ENOENT);
+}
+
+long libbpf_get_error(const void *ptr)
+{
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+	return 0;
+}
+
+int bpf_prog_load(const char *file, enum bpf_prog_type type,
+		  struct bpf_object **pobj, int *prog_fd)
+{
+	struct bpf_program *prog;
+	struct bpf_object *obj;
+	int err;
+
+	obj = bpf_object__open(file);
+	if (IS_ERR(obj))
+		return -ENOENT;
+
+	prog = bpf_program__next(NULL, obj);
+	if (!prog) {
+		bpf_object__close(obj);
+		return -ENOENT;
+	}
+
+	bpf_program__set_type(prog, type);
+	err = bpf_object__load(obj);
+	if (err) {
+		bpf_object__close(obj);
+		return -EINVAL;
+	}
+
+	*pobj = obj;
+	*prog_fd = bpf_program__fd(prog);
+	return 0;
+}