Commit 55b4de58 authored by Quentin Monnet's avatar Quentin Monnet Committed by Alexei Starovoitov
Browse files

bpftool: Remove asserts from JIT disassembler 



The JIT disassembler in bpftool is the only components (with the JSON
writer) using asserts to check the return values of functions. But it
does not do so in a consistent way, and diasm_print_insn() returns no
value, although sometimes the operation failed.

Remove the asserts, and instead check the return values, print messages
on errors, and propagate the error to the caller from prog.c.

Remove the inclusion of assert.h from jit_disasm.c, and also from map.c
where it is unused.

Signed-off-by: default avatarQuentin Monnet <quentin@isovalent.com>
Tested-by: default avatarNiklas Söderlund <niklas.soderlund@corigine.com>
Acked-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20221025150329.97371-3-quentin@isovalent.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b3d84af7

tools/bpf/bpftool/jit_disasm.c

+35 −16
Original line number Diff line number Diff line
@@ -18,7 +18,6 @@ 
#include <stdarg.h>

#include <stdint.h>

#include <stdlib.h>

#include <assert.h>

#include <unistd.h>

#include <string.h>

#include <bfd.h>
@@ -31,14 +30,18 @@ 
#include "json_writer.h"

#include "main.h"



static void get_exec_path(char *tpath, size_t size)

static int get_exec_path(char *tpath, size_t size)

{

	const char *path = "/proc/self/exe";

	ssize_t len;



	len = readlink(path, tpath, size - 1);

	assert(len > 0);

	if (len <= 0)

		return -1;



	tpath[len] = 0;



	return 0;

}



static int oper_count;
@@ -99,7 +102,7 @@ static int fprintf_json_styled(void *out, 
	return r;

}



void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,

int disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,

		      const char *arch, const char *disassembler_options,

		      const struct btf *btf,

		      const struct bpf_prog_linfo *prog_linfo,
@@ -108,21 +111,30 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes, 
{

	const struct bpf_line_info *linfo = NULL;

	disassembler_ftype disassemble;

	int count, i, pc = 0, err = -1;

	struct disassemble_info info;

	unsigned int nr_skip = 0;

	int count, i, pc = 0;

	char tpath[PATH_MAX];

	bfd *bfdf;



	if (!len)

		return;

		return -1;



	memset(tpath, 0, sizeof(tpath));

	get_exec_path(tpath, sizeof(tpath));

	if (get_exec_path(tpath, sizeof(tpath))) {

		p_err("failed to create disasembler (get_exec_path)");

		return -1;

	}



	bfdf = bfd_openr(tpath, NULL);

	assert(bfdf);

	assert(bfd_check_format(bfdf, bfd_object));

	if (!bfdf) {

		p_err("failed to create disassembler (bfd_openr)");

		return -1;

	}

	if (!bfd_check_format(bfdf, bfd_object)) {

		p_err("failed to create disassembler (bfd_check_format)");

		goto exit_close;

	}



	if (json_output)

		init_disassemble_info_compat(&info, stdout,
@@ -141,7 +153,7 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes, 
			bfdf->arch_info = inf;

		} else {

			p_err("No libbfd support for %s", arch);

			return;

			goto exit_close;

		}

	}
@@ -162,7 +174,10 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes, 
#else

	disassemble = disassembler(bfdf);

#endif

	assert(disassemble);

	if (!disassemble) {

		p_err("failed to create disassembler");

		goto exit_close;

	}



	if (json_output)

		jsonw_start_array(json_wtr);
@@ -226,7 +241,11 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes, 
	if (json_output)

		jsonw_end_array(json_wtr);



	err = 0;



exit_close:

	bfd_close(bfdf);

	return err;

}



int disasm_init(void)

tools/bpf/bpftool/main.h

+13 −12
Original line number Diff line number Diff line
@@ -173,7 +173,7 @@ int map_parse_fd_and_info(int *argc, char ***argv, void *info, __u32 *info_len); 


struct bpf_prog_linfo;

#ifdef HAVE_LIBBFD_SUPPORT

void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,

int disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,

		      const char *arch, const char *disassembler_options,

		      const struct btf *btf,

		      const struct bpf_prog_linfo *prog_linfo,
@@ -182,13 +182,14 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes, 
int disasm_init(void);

#else

static inline

void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,

int disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,

		      const char *arch, const char *disassembler_options,

		      const struct btf *btf,

		      const struct bpf_prog_linfo *prog_linfo,

		      __u64 func_ksym, unsigned int func_idx,

		      bool linum)

{

	return 0;

}

static inline int disasm_init(void)

{

tools/bpf/bpftool/map.c

+0 −1
Original line number Diff line number Diff line 
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

/* Copyright (C) 2017-2018 Netronome Systems, Inc. */



#include <assert.h>

#include <errno.h>

#include <fcntl.h>

#include <linux/err.h>

tools/bpf/bpftool/prog.c

+9 −6
Original line number Diff line number Diff line
@@ -822,10 +822,11 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode, 
					printf("%s:\n", sym_name);

				}



				disasm_print_insn(img, lens[i], opcodes,

				if (disasm_print_insn(img, lens[i], opcodes,

						      name, disasm_opt, btf,

						      prog_linfo, ksyms[i], i,

						  linum);

						      linum))

					goto exit_free;



				img += lens[i];
@@ -838,8 +839,10 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode, 
			if (json_output)

				jsonw_end_array(json_wtr);

		} else {

			disasm_print_insn(buf, member_len, opcodes, name,

					  disasm_opt, btf, NULL, 0, 0, false);

			if (disasm_print_insn(buf, member_len, opcodes, name,

					      disasm_opt, btf, NULL, 0, 0,

					      false))

				goto exit_free;

		}

	} else if (visual) {

		if (json_output)