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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>
Subject: [PATCHv4 bpf-next 12/28] libbpf: Add elf_resolve_pattern_offsets function
Date: Thu, 20 Jul 2023 13:35:34 +0200	[thread overview]
Message-ID: <20230720113550.369257-13-jolsa@kernel.org> (raw)
In-Reply-To: <20230720113550.369257-1-jolsa@kernel.org>

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 <jolsa@kernel.org>
---
 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 */
-- 
2.41.0


  parent reply	other threads:[~2023-07-20 11:37 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-20 11:35 [PATCHv4 bpf-next 00/28] bpf: Add multi uprobe link Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 01/28] bpf: Switch BPF_F_KPROBE_MULTI_RETURN macro to enum Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 02/28] bpf: Add attach_type checks under bpf_prog_attach_check_attach_type Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 03/28] bpf: Add multi uprobe link Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 04/28] bpf: Add cookies support for uprobe_multi link Jiri Olsa
2023-07-21  2:18   ` Yafang Shao
2023-07-21  7:39     ` Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 05/28] bpf: Add pid filter " Jiri Olsa
2023-07-21  2:55   ` Yafang Shao
2023-07-21  8:31     ` Oleg Nesterov
2023-07-21  8:54       ` Oleg Nesterov
2023-07-21  9:05         ` Yafang Shao
2023-07-21 10:41           ` Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 06/28] bpf: Add bpf_get_func_ip helper support for uprobe link Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 07/28] libbpf: Add uprobe_multi attach type and link names Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 08/28] libbpf: Move elf_find_func_offset* functions to elf object Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 09/28] libbpf: Add elf_open/elf_close functions Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 10/28] libbpf: Add elf symbol iterator Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 11/28] libbpf: Add elf_resolve_syms_offsets function Jiri Olsa
2023-07-20 11:35 ` Jiri Olsa [this message]
2023-07-20 11:35 ` [PATCHv4 bpf-next 13/28] libbpf: Add bpf_link_create support for multi uprobes Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 14/28] libbpf: Add bpf_program__attach_uprobe_multi function Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 15/28] libbpf: Add support for u[ret]probe.multi[.s] program sections Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 16/28] libbpf: Add uprobe multi link detection Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 17/28] libbpf: Add uprobe multi link support to bpf_program__attach_usdt Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 18/28] selftests/bpf: Move get_time_ns to testing_helpers.h Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 19/28] selftests/bpf: Add uprobe_multi skel test Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 20/28] selftests/bpf: Add uprobe_multi api test Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 21/28] selftests/bpf: Add uprobe_multi link test Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 22/28] selftests/bpf: Add uprobe_multi test program Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 23/28] selftests/bpf: Add uprobe_multi bench test Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 24/28] selftests/bpf: Add uprobe_multi usdt test code Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 25/28] selftests/bpf: Add uprobe_multi usdt bench test Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 26/28] selftests/bpf: Add uprobe_multi cookie test Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 27/28] selftests/bpf: Add uprobe_multi pid filter tests Jiri Olsa
2023-07-20 11:35 ` [PATCHv4 bpf-next 28/28] selftests/bpf: Add extra link to uprobe_multi tests Jiri Olsa

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