From patchwork Thu Jul 20 11:35:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 13320367 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4A7F2174E9 for ; Thu, 20 Jul 2023 11:37:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D408C433C8; Thu, 20 Jul 2023 11:37:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1689853079; bh=yHTHYQLY4tq1KnhJUM3JNitxWtkjwWdBn0X1+Ze/bJs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lPLC6fMdKM3lIkRWVSRkh5iCiAEqfp8SgfH0PtmAV7oXvJH23uj1wrqV5d3ToDlri 9241NPIfiM8/iZdSrDHKL5l9Doy53vG0TgaxmdIwyuz8wdPoy5NaHOW0r22rN0A3EZ j4A0wE5fxIQ+f+GEqEAhrT3KuwmVhIPBgX4Y+Ijyrghb+rpnjGsuhdeJnBUNZj32dy JjRXTm7PeoV/ILw8z2ont7IAAFWQaZp7LondUxJv/P6ZqrIWsnnAedVaFCEfI8QaWT 6iyokAUIrbCy8x9U48W2F1cO0T15MBf4bmdzzDH5yPgqmHEQP5IkpdkhDXJAwVtj6m GqpVqgj7zjgww== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo Subject: [PATCHv4 bpf-next 12/28] libbpf: Add elf_resolve_pattern_offsets function Date: Thu, 20 Jul 2023 13:35:34 +0200 Message-ID: <20230720113550.369257-13-jolsa@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230720113550.369257-1-jolsa@kernel.org> References: <20230720113550.369257-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net Adding elf_resolve_pattern_offsets function that looks up offsets for symbols specified by pattern argument. The 'pattern' argument allows wildcards (*?' supported). Offsets are returned in allocated array together with its size and needs to be released by the caller. Signed-off-by: Jiri Olsa --- tools/lib/bpf/elf.c | 61 +++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.c | 2 +- tools/lib/bpf/libbpf_internal.h | 5 +++ 3 files changed, 67 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/elf.c b/tools/lib/bpf/elf.c index 8c512641c1d7..9d0296c1726a 100644 --- a/tools/lib/bpf/elf.c +++ b/tools/lib/bpf/elf.c @@ -377,3 +377,64 @@ int elf_resolve_syms_offsets(const char *binary_path, int cnt, elf_close(&elf_fd); return err; } + +/* + * Return offsets in @poffsets for symbols specified by @pattern argument. + * On success returns 0 and offsets are returned in allocated @poffsets + * array with the @pctn size, that needs to be released by the caller. + */ +int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern, + unsigned long **poffsets, size_t *pcnt) +{ + int sh_types[2] = { SHT_SYMTAB, SHT_DYNSYM }; + unsigned long *offsets = NULL; + size_t cap = 0, cnt = 0; + struct elf_fd elf_fd; + int err = 0, i; + + err = elf_open(binary_path, &elf_fd); + if (err) + return err; + + for (i = 0; i < ARRAY_SIZE(sh_types); i++) { + struct elf_sym_iter iter; + struct elf_sym *sym; + + err = elf_sym_iter_new(&iter, elf_fd.elf, binary_path, sh_types[i], STT_FUNC); + if (err == -ENOENT) + continue; + if (err) + goto out; + + while ((sym = elf_sym_iter_next(&iter))) { + if (!glob_match(sym->name, pattern)) + continue; + + err = libbpf_ensure_mem((void **) &offsets, &cap, sizeof(*offsets), + cnt + 1); + if (err) + goto out; + + offsets[cnt++] = elf_sym_offset(sym); + } + + /* If we found anything in the first symbol section, + * do not search others to avoid duplicates. + */ + if (cnt) + break; + } + + if (cnt) { + *poffsets = offsets; + *pcnt = cnt; + } else { + err = -ENOENT; + } + +out: + if (err) + free(offsets); + elf_close(&elf_fd); + return err; +} diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ed1595590663..b690a729d2c1 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10544,7 +10544,7 @@ struct bpf_link *bpf_program__attach_ksyscall(const struct bpf_program *prog, } /* Adapted from perf/util/string.c */ -static bool glob_match(const char *str, const char *pat) +bool glob_match(const char *str, const char *pat) { while (*str && *pat && *pat != '*') { if (*pat == '?') { /* Matches any single character */ diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 92851c5f912d..ead551318fec 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -578,6 +578,8 @@ static inline bool is_pow_of_2(size_t x) #define PROG_LOAD_ATTEMPTS 5 int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts); +bool glob_match(const char *str, const char *pat); + long elf_find_func_offset(Elf *elf, const char *binary_path, const char *name); long elf_find_func_offset_from_file(const char *binary_path, const char *name); @@ -591,4 +593,7 @@ void elf_close(struct elf_fd *elf_fd); int elf_resolve_syms_offsets(const char *binary_path, int cnt, const char **syms, unsigned long **poffsets); +int elf_resolve_pattern_offsets(const char *binary_path, const char *pattern, + unsigned long **poffsets, size_t *pcnt); + #endif /* __LIBBPF_LIBBPF_INTERNAL_H */