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tools: bpf: make use of reallocarray reallocarray() is a safer variant of realloc which checks for multiplication overflow in case of array allocation. Since it's not available in Glibc < 2.26 import kernel's overflow.h and add a static inline implementation when needed. Use feature detection to probe for existence of reallocarray. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jiong Wang <jiong.wang@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-11 05:43:05 +08:00
// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <stdlib.h>
int main(void)
{
return !!reallocarray(NULL, 1, 1);
}
tools build: Add test-reallocarray.c to test-all.c to fix the build When a test is in the FEATURE_TESTS_BASIC list in tools/build/Makefile.feature must be added to tools/build/feature/test-all.c, because the successfull compilation and linking of that test-all.bin file means that all the features listed in FEATURE_TESTS_BASIC are present in the system, so we don't have to go on feature by feature test building them. Since reallocarray() is expected to be present in modern systems, it has a place in FEATURE_TESTS_BASIC, so that we speed up the build process building just that file. For older systems, such as ubuntu:16.04 (build failure reported by Jin Yao) debian:8, and for the current flagship RHEL distro, RHEL7, the build will fail as test-all.bin (without test-reallocarray.c included) passes but reallocarray() isn't present, making the build fail with: CC /tmp/build/perf/libbpf.o MKDIR /tmp/build/perf/fs/ CC /tmp/build/perf/fs/tracing_path.o LD /tmp/build/perf/fd/libapi-in.o CC /tmp/build/perf/bpf.o libbpf.c: In function 'bpf_object__add_program': libbpf.c:367:10: error: implicit declaration of function 'reallocarray' [-Werror=implicit-function-declaration] progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0])); ^ libbpf.c:367:2: error: nested extern declaration of 'reallocarray' [-Werror=nested-externs] progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0])); ^ libbpf.c:367:8: error: assignment makes pointer from integer without a cast [-Werror=int-conversion] progs = reallocarray(progs, nr_progs + 1, sizeof(progs[0])); ^ libbpf.c: In function 'bpf_object__elf_collect': libbpf.c:887:10: error: assignment makes pointer from integer without a cast [-Werror=int-conversion] reloc = reallocarray(reloc, nr_reloc, ^ libbpf.c: In function 'bpf_program__reloc_text': libbpf.c:1394:12: error: assignment makes pointer from integer without a cast [-Werror=int-conversion] new_insn = reallocarray(prog->insns, new_cnt, sizeof(*insn)); ^ CC /tmp/build/perf/nlattr.o Even with: $ grep reallocarray /tmp/build/perf/FEATURE-DUMP feature-reallocarray=1 $ Which ubuntu:16.04.5 LTS doesn't have: perfbuilder@38a153a1bba8:/$ head -2 /etc/os-release NAME="Ubuntu" VERSION="16.04.5 LTS (Xenial Xerus)" perfbuilder@38a153a1bba8:/$ find /usr/include/ -name "*.h" | xargs grep -w reallocarray perfbuilder@38a153a1bba8:/$ Fix it by including it to test-all.c, which ends up forcing the individual tests to be triggered and for the build process to notice that indeed reallocarray() is not there: perfbuilder@38a153a1bba8:/$ cat /tmp/build/perf/feature/test-all.make.output In file included from test-all.c:178:0: test-reallocarray.c: In function 'main_test_reallocarray': test-reallocarray.c:7:11: error: implicit declaration of function 'reallocarray' [-Werror=implicit-function-declaration] return !!reallocarray(NULL, 1, 1); ^ cc1: all warnings being treated as errors perfbuilder@38a153a1bba8:/$ That is the only test that is failing on Ubuntu 16.03.5 LTS, so all tests are forced: perfbuilder@38a153a1bba8:/tmp/build/perf/feature$ ls -lSr *.make.output <SNIP successful tests> -rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 15:00 test-dwarf.make.output -rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 14:16 test-cplus-demangle.make.output -rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 15:00 test-bpf.make.output -rw-r--r--. 1 perfbuilder perfbuilder 0 Feb 14 15:00 test-backtrace.make.output -rw-r--r--. 1 perfbuilder perfbuilder 104 Feb 14 15:00 test-bionic.make.output -rw-r--r--. 1 perfbuilder perfbuilder 107 Feb 14 15:00 test-libunwind-x86.make.output -rw-r--r--. 1 perfbuilder perfbuilder 115 Feb 14 15:00 test-libunwind-aarch64.make.output -rw-r--r--. 1 perfbuilder perfbuilder 122 Feb 14 15:00 test-libbabeltrace.make.output -rw-r--r--. 1 perfbuilder perfbuilder 254 Feb 14 15:00 test-reallocarray.make.output -rw-r--r--. 1 perfbuilder perfbuilder 312 Feb 14 15:00 test-all.make.output perfbuilder@38a153a1bba8:/tmp/build/perf/feature$ And that reallocarray() one shows: perfbuilder@38a153a1bba8:/tmp/build/perf/feature$ cat test-reallocarray.make.output test-reallocarray.c: In function 'main': test-reallocarray.c:7:11: error: implicit declaration of function 'reallocarray' [-Werror=implicit-function-declaration] return !!reallocarray(NULL, 1, 1); ^ cc1: all warnings being treated as errors perfbuilder@38a153a1bba8:/tmp/build/perf/feature$ Which now generates the expected result: perfbuilder@38a153a1bba8:~$ grep reallocarray /tmp/build/perf/FEATURE-DUMP feature-reallocarray=0 perfbuilder@38a153a1bba8:~$ The fallback mechanism kicks in and libbpf and perf are again buildable in systems without reallocarray(): $ cat tools/include/tools/libc_compat.h // SPDX-License-Identifier: (LGPL-2.0+ OR BSD-2-Clause) /* Copyright (C) 2018 Netronome Systems, Inc. */ #ifndef __TOOLS_LIBC_COMPAT_H #define __TOOLS_LIBC_COMPAT_H #include <stdlib.h> #include <linux/overflow.h> #ifdef COMPAT_NEED_REALLOCARRAY static inline void *reallocarray(void *ptr, size_t nmemb, size_t size) { size_t bytes; if (unlikely(check_mul_overflow(nmemb, size, &bytes))) return NULL; return realloc(ptr, bytes); } #endif #endif $ Reported-by: Jin Yao <yao.jin@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jakub Kicinski <jakub.kicinski@netronome.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Yonghong Song <yhs@fb.com> Fixes: 531b014e7a2f ("tools: bpf: make use of reallocarray") Link: https://lkml.kernel.org/n/tip-aonqku8axii8rxki5g11w40b@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 23:01:04 +08:00
#undef _GNU_SOURCE