diff mbox series

[bpf-next,v2,2/8] bpftool: Remove asserts from JIT disassembler

Message ID 20220911201451.12368-3-quentin@isovalent.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series bpftool: Add LLVM as default library for disassembling JIT-ed programs | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 1 maintainers not CCed: martin.lau@linux.dev
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 176 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-VM_Test-7 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-8 success Logs for test_maps on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_progs on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_progs on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-12 success Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-13 success Logs for test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-14 success Logs for test_progs_no_alu32 on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-15 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-PR fail PR summary
bpf/vmtest-bpf-next-VM_Test-6 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-2 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-3 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-1 success Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-16 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-17 success Logs for test_verifier on x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-4 success Logs for llvm-toolchain
bpf/vmtest-bpf-next-VM_Test-5 success Logs for set-matrix

Commit Message

Quentin Monnet Sept. 11, 2022, 8:14 p.m. UTC 
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: Quentin Monnet <quentin@isovalent.com>
Tested-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Acked-by: Song Liu <song@kernel.org>
---
 tools/bpf/bpftool/jit_disasm.c | 51 +++++++++++++++++++++++-----------
 tools/bpf/bpftool/main.h       | 25 +++++++++--------
 tools/bpf/bpftool/map.c        |  1 -
 tools/bpf/bpftool/prog.c       | 15 ++++++----
 4 files changed, 57 insertions(+), 35 deletions(-)
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/jit_disasm.c b/tools/bpf/bpftool/jit_disasm.c
index 71cb258ab0ee..723a9b799a0c 100644
--- a/tools/bpf/bpftool/jit_disasm.c
+++ b/tools/bpf/bpftool/jit_disasm.c
@@ -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;
@@ -99,30 +102,39 @@  static int fprintf_json_styled(void *out,
 	return r;
 }
 
-void 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)
+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)
 {
 	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)
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 5e5060c2ac04..c9e171082cf6 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -173,22 +173,23 @@  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,
-		       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);
+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);
 int disasm_init(void);
 #else
 static inline
-void 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)
+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)
 {
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 38b6bc9c26c3..a0e573589811 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -1,7 +1,6 @@ 
 // 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>
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index a31ae9f0c307..345dca656a34 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -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,
-						  name, disasm_opt, btf,
-						  prog_linfo, ksyms[i], i,
-						  linum);
+				if (disasm_print_insn(img, lens[i], opcodes,
+						      name, disasm_opt, btf,
+						      prog_linfo, ksyms[i], i,
+						      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)