bpftool: use libbpf's btf__parse_elf API (58650cc4) · Commits · 戴 / test

tools/bpf/bpftool/btf.c

+8 −109

Original line number	Diff line number	Diff line
		@@ -8,8 +8,8 @@
		#include <stdio.h>
		#include <string.h>
		#include <unistd.h>
		#include <gelf.h>
		#include <bpf.h>
		#include <libbpf.h>
		#include <linux/btf.h>

		#include "btf.h"
		@@ -340,112 +340,6 @@ static int dump_btf_raw(const struct btf *btf,
		return 0;
		}

		static bool check_btf_endianness(GElf_Ehdr *ehdr)
		{
		static unsigned int const endian = 1;

		switch (ehdr->e_ident[EI_DATA]) {
		case ELFDATA2LSB:
		return (unsigned char const )&endian == 1;
		case ELFDATA2MSB:
		return (unsigned char const )&endian == 0;
		default:
		return 0;
		}
		}

		static int btf_load_from_elf(const char path, struct btf *btf)
		{
		int err = -1, fd = -1, idx = 0;
		Elf_Data *btf_data = NULL;
		Elf_Scn *scn = NULL;
		Elf *elf = NULL;
		GElf_Ehdr ehdr;

		if (elf_version(EV_CURRENT) == EV_NONE) {
		p_err("failed to init libelf for %s", path);
		return -1;
		}

		fd = open(path, O_RDONLY);
		if (fd < 0) {
		p_err("failed to open %s: %s", path, strerror(errno));
		return -1;
		}

		elf = elf_begin(fd, ELF_C_READ, NULL);
		if (!elf) {
		p_err("failed to open %s as ELF file", path);
		goto done;
		}
		if (!gelf_getehdr(elf, &ehdr)) {
		p_err("failed to get EHDR from %s", path);
		goto done;
		}
		if (!check_btf_endianness(&ehdr)) {
		p_err("non-native ELF endianness is not supported");
		goto done;
		}
		if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) {
		p_err("failed to get e_shstrndx from %s\n", path);
		goto done;
		}

		while ((scn = elf_nextscn(elf, scn)) != NULL) {
		GElf_Shdr sh;
		char *name;

		idx++;
		if (gelf_getshdr(scn, &sh) != &sh) {
		p_err("failed to get section(%d) header from %s",
		idx, path);
		goto done;
		}
		name = elf_strptr(elf, ehdr.e_shstrndx, sh.sh_name);
		if (!name) {
		p_err("failed to get section(%d) name from %s",
		idx, path);
		goto done;
		}
		if (strcmp(name, BTF_ELF_SEC) == 0) {
		btf_data = elf_getdata(scn, 0);
		if (!btf_data) {
		p_err("failed to get section(%d, %s) data from %s",
		idx, name, path);
		goto done;
		}
		break;
		}
		}

		if (!btf_data) {
		p_err("%s ELF section not found in %s", BTF_ELF_SEC, path);
		goto done;
		}

		*btf = btf__new(btf_data->d_buf, btf_data->d_size);
		if (IS_ERR(*btf)) {
		err = PTR_ERR(*btf);
		*btf = NULL;
		p_err("failed to load BTF data from %s: %s",
		path, strerror(err));
		goto done;
		}

		err = 0;
		done:
		if (err) {
		if (*btf) {
		btf__free(*btf);
		*btf = NULL;
		}
		}
		if (elf)
		elf_end(elf);
		close(fd);
		return err;
		}

		static int do_dump(int argc, char **argv)
		{
		struct btf *btf = NULL;
		@@ -522,9 +416,14 @@ static int do_dump(int argc, char **argv)
		}
		NEXT_ARG();
		} else if (is_prefix(src, "file")) {
		err = btf_load_from_elf(*argv, &btf);
		if (err)
		btf = btf__parse_elf(*argv, NULL);
		if (IS_ERR(btf)) {
		err = PTR_ERR(btf);
		btf = NULL;
		p_err("failed to load BTF from %s: %s",
		*argv, strerror(err));
		goto done;
		}
		NEXT_ARG();
		} else {
		err = -1;

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