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* [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function
@ 2023-03-31  9:31 Jiri Olsa
  2023-03-31  9:31 ` [PATCHv4 bpf-next 1/3] selftests/bpf: Add err.h header Jiri Olsa
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Jiri Olsa @ 2023-03-31  9:31 UTC (permalink / raw)
  To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
  Cc: bpf, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
	KP Singh, Stanislav Fomichev, Hao Luo

hi,
this selftests cleanup was previously posted as part of file build id changes [1],
which might take more time, so I'm sending the selftests changes separately so it
won't get stuck.

v4 changes:
  - added size argument to read_build_id [Andrii]
  - condition changes in parse_build_id_buf [Andrii]
  - use ELF_C_READ_MMAP in elf_begin [Andrii]
  - return -ENOENT in read_build_id if build id is not found [Andrii]
  - dropped elf class check [Andrii]

thanks,
jirka


[1] https://lore.kernel.org/bpf/20230316170149.4106586-1-jolsa@kernel.org/
---
Jiri Olsa (3):
      selftests/bpf: Add err.h header
      selftests/bpf: Add read_build_id function
      selftests/bpf: Replace extract_build_id with read_build_id

 tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c     | 19 +++++++------------
 tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c | 17 ++++++-----------
 tools/testing/selftests/bpf/progs/err.h                          | 18 ++++++++++++++++++
 tools/testing/selftests/bpf/progs/profiler.inc.h                 |  3 +--
 tools/testing/selftests/bpf/test_progs.c                         | 25 -------------------------
 tools/testing/selftests/bpf/test_progs.h                         |  1 -
 tools/testing/selftests/bpf/trace_helpers.c                      | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/trace_helpers.h                      |  5 +++++
 8 files changed, 119 insertions(+), 51 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/err.h

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCHv4 bpf-next 1/3] selftests/bpf: Add err.h header
  2023-03-31  9:31 [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function Jiri Olsa
@ 2023-03-31  9:31 ` Jiri Olsa
  2023-03-31  9:31 ` [PATCHv4 bpf-next 2/3] selftests/bpf: Add read_build_id function Jiri Olsa
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 5+ messages in thread
From: Jiri Olsa @ 2023-03-31  9:31 UTC (permalink / raw)
  To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
  Cc: bpf, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
	KP Singh, Stanislav Fomichev, Hao Luo

Moving error macros from profiler.inc.h to new err.h header.
It will be used in following changes.

Also adding PTR_ERR macro that will be used in following changes.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/testing/selftests/bpf/progs/err.h        | 18 ++++++++++++++++++
 .../testing/selftests/bpf/progs/profiler.inc.h |  3 +--
 2 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/err.h

diff --git a/tools/testing/selftests/bpf/progs/err.h b/tools/testing/selftests/bpf/progs/err.h
new file mode 100644
index 000000000000..d66d283d9e59
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/err.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ERR_H__
+#define __ERR_H__
+
+#define MAX_ERRNO 4095
+#define IS_ERR_VALUE(x) (unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO
+
+static inline int IS_ERR_OR_NULL(const void *ptr)
+{
+	return !ptr || IS_ERR_VALUE((unsigned long)ptr);
+}
+
+static inline long PTR_ERR(const void *ptr)
+{
+	return (long) ptr;
+}
+
+#endif /* __ERR_H__ */
diff --git a/tools/testing/selftests/bpf/progs/profiler.inc.h b/tools/testing/selftests/bpf/progs/profiler.inc.h
index 875513866032..f799d87e8700 100644
--- a/tools/testing/selftests/bpf/progs/profiler.inc.h
+++ b/tools/testing/selftests/bpf/progs/profiler.inc.h
@@ -6,6 +6,7 @@
 #include <bpf/bpf_tracing.h>
 
 #include "profiler.h"
+#include "err.h"
 
 #ifndef NULL
 #define NULL 0
@@ -16,7 +17,6 @@
 #define O_DIRECTORY 00200000
 #define __O_TMPFILE 020000000
 #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
-#define MAX_ERRNO 4095
 #define S_IFMT 00170000
 #define S_IFSOCK 0140000
 #define S_IFLNK 0120000
@@ -34,7 +34,6 @@
 #define S_ISBLK(m) (((m)&S_IFMT) == S_IFBLK)
 #define S_ISFIFO(m) (((m)&S_IFMT) == S_IFIFO)
 #define S_ISSOCK(m) (((m)&S_IFMT) == S_IFSOCK)
-#define IS_ERR_VALUE(x) (unsigned long)(void*)(x) >= (unsigned long)-MAX_ERRNO
 
 #define KILL_DATA_ARRAY_SIZE 8
 
-- 
2.39.2


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* [PATCHv4 bpf-next 2/3] selftests/bpf: Add read_build_id function
  2023-03-31  9:31 [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function Jiri Olsa
  2023-03-31  9:31 ` [PATCHv4 bpf-next 1/3] selftests/bpf: Add err.h header Jiri Olsa
@ 2023-03-31  9:31 ` Jiri Olsa
  2023-03-31  9:31 ` [PATCHv4 bpf-next 3/3] selftests/bpf: Replace extract_build_id with read_build_id Jiri Olsa
  2023-03-31 16:50 ` [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function patchwork-bot+netdevbpf
  3 siblings, 0 replies; 5+ messages in thread
From: Jiri Olsa @ 2023-03-31  9:31 UTC (permalink / raw)
  To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
  Cc: bpf, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
	KP Singh, Stanislav Fomichev, Hao Luo

Adding read_build_id function that parses out build id from
specified binary.

It will replace extract_build_id and also be used in following
changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/testing/selftests/bpf/trace_helpers.c | 82 +++++++++++++++++++++
 tools/testing/selftests/bpf/trace_helpers.h |  5 ++
 2 files changed, 87 insertions(+)

diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c
index 934bf28fc888..9b070cdf44ac 100644
--- a/tools/testing/selftests/bpf/trace_helpers.c
+++ b/tools/testing/selftests/bpf/trace_helpers.c
@@ -11,6 +11,9 @@
 #include <linux/perf_event.h>
 #include <sys/mman.h>
 #include "trace_helpers.h"
+#include <linux/limits.h>
+#include <libelf.h>
+#include <gelf.h>
 
 #define TRACEFS_PIPE	"/sys/kernel/tracing/trace_pipe"
 #define DEBUGFS_PIPE	"/sys/kernel/debug/tracing/trace_pipe"
@@ -234,3 +237,82 @@ ssize_t get_rel_offset(uintptr_t addr)
 	fclose(f);
 	return -EINVAL;
 }
+
+static int
+parse_build_id_buf(const void *note_start, Elf32_Word note_size, char *build_id)
+{
+	Elf32_Word note_offs = 0;
+
+	while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
+		Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
+
+		if (nhdr->n_type == 3 && nhdr->n_namesz == sizeof("GNU") &&
+		    !strcmp((char *)(nhdr + 1), "GNU") && nhdr->n_descsz > 0 &&
+		    nhdr->n_descsz <= BPF_BUILD_ID_SIZE) {
+			memcpy(build_id, note_start + note_offs +
+			       ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr), nhdr->n_descsz);
+			memset(build_id + nhdr->n_descsz, 0, BPF_BUILD_ID_SIZE - nhdr->n_descsz);
+			return (int) nhdr->n_descsz;
+		}
+
+		note_offs = note_offs + sizeof(Elf32_Nhdr) +
+			   ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
+	}
+
+	return -ENOENT;
+}
+
+/* Reads binary from *path* file and returns it in the *build_id* buffer
+ * with *size* which is expected to be at least BPF_BUILD_ID_SIZE bytes.
+ * Returns size of build id on success. On error the error value is
+ * returned.
+ */
+int read_build_id(const char *path, char *build_id, size_t size)
+{
+	int fd, err = -EINVAL;
+	Elf *elf = NULL;
+	GElf_Ehdr ehdr;
+	size_t max, i;
+
+	if (size < BPF_BUILD_ID_SIZE)
+		return -EINVAL;
+
+	fd = open(path, O_RDONLY | O_CLOEXEC);
+	if (fd < 0)
+		return -errno;
+
+	(void)elf_version(EV_CURRENT);
+
+	elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
+	if (!elf)
+		goto out;
+	if (elf_kind(elf) != ELF_K_ELF)
+		goto out;
+	if (!gelf_getehdr(elf, &ehdr))
+		goto out;
+
+	for (i = 0; i < ehdr.e_phnum; i++) {
+		GElf_Phdr mem, *phdr;
+		char *data;
+
+		phdr = gelf_getphdr(elf, i, &mem);
+		if (!phdr)
+			goto out;
+		if (phdr->p_type != PT_NOTE)
+			continue;
+		data = elf_rawfile(elf, &max);
+		if (!data)
+			goto out;
+		if (phdr->p_offset + phdr->p_memsz > max)
+			goto out;
+		err = parse_build_id_buf(data + phdr->p_offset, phdr->p_memsz, build_id);
+		if (err > 0)
+			break;
+	}
+
+out:
+	if (elf)
+		elf_end(elf);
+	close(fd);
+	return err;
+}
diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
index 53efde0e2998..876f3e711df6 100644
--- a/tools/testing/selftests/bpf/trace_helpers.h
+++ b/tools/testing/selftests/bpf/trace_helpers.h
@@ -4,6 +4,9 @@
 
 #include <bpf/libbpf.h>
 
+#define __ALIGN_MASK(x, mask)	(((x)+(mask))&~(mask))
+#define ALIGN(x, a)		__ALIGN_MASK(x, (typeof(x))(a)-1)
+
 struct ksym {
 	long addr;
 	char *name;
@@ -23,4 +26,6 @@ void read_trace_pipe(void);
 ssize_t get_uprobe_offset(const void *addr);
 ssize_t get_rel_offset(uintptr_t addr);
 
+int read_build_id(const char *path, char *build_id, size_t size);
+
 #endif
-- 
2.39.2


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* [PATCHv4 bpf-next 3/3] selftests/bpf: Replace extract_build_id with read_build_id
  2023-03-31  9:31 [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function Jiri Olsa
  2023-03-31  9:31 ` [PATCHv4 bpf-next 1/3] selftests/bpf: Add err.h header Jiri Olsa
  2023-03-31  9:31 ` [PATCHv4 bpf-next 2/3] selftests/bpf: Add read_build_id function Jiri Olsa
@ 2023-03-31  9:31 ` Jiri Olsa
  2023-03-31 16:50 ` [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function patchwork-bot+netdevbpf
  3 siblings, 0 replies; 5+ messages in thread
From: Jiri Olsa @ 2023-03-31  9:31 UTC (permalink / raw)
  To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko
  Cc: bpf, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
	KP Singh, Stanislav Fomichev, Hao Luo

Replacing extract_build_id with read_build_id that parses out
build id directly from elf without using readelf tool.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 .../bpf/prog_tests/stacktrace_build_id.c      | 19 ++++++--------
 .../bpf/prog_tests/stacktrace_build_id_nmi.c  | 17 +++++--------
 tools/testing/selftests/bpf/test_progs.c      | 25 -------------------
 tools/testing/selftests/bpf/test_progs.h      |  1 -
 4 files changed, 13 insertions(+), 49 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c
index 9ad09a6c538a..b7ba5cd47d96 100644
--- a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c
+++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c
@@ -7,13 +7,12 @@ void test_stacktrace_build_id(void)
 
 	int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
 	struct test_stacktrace_build_id *skel;
-	int err, stack_trace_len;
+	int err, stack_trace_len, build_id_size;
 	__u32 key, prev_key, val, duration = 0;
-	char buf[256];
-	int i, j;
+	char buf[BPF_BUILD_ID_SIZE];
 	struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
 	int build_id_matches = 0;
-	int retry = 1;
+	int i, retry = 1;
 
 retry:
 	skel = test_stacktrace_build_id__open_and_load();
@@ -52,9 +51,10 @@ void test_stacktrace_build_id(void)
 		  "err %d errno %d\n", err, errno))
 		goto cleanup;
 
-	err = extract_build_id(buf, 256);
+	build_id_size = read_build_id("urandom_read", buf, sizeof(buf));
+	err = build_id_size < 0 ? build_id_size : 0;
 
-	if (CHECK(err, "get build_id with readelf",
+	if (CHECK(err, "read_build_id",
 		  "err %d errno %d\n", err, errno))
 		goto cleanup;
 
@@ -64,8 +64,6 @@ void test_stacktrace_build_id(void)
 		goto cleanup;
 
 	do {
-		char build_id[64];
-
 		err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs);
 		if (CHECK(err, "lookup_elem from stackmap",
 			  "err %d, errno %d\n", err, errno))
@@ -73,10 +71,7 @@ void test_stacktrace_build_id(void)
 		for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
 			if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
 			    id_offs[i].offset != 0) {
-				for (j = 0; j < 20; ++j)
-					sprintf(build_id + 2 * j, "%02x",
-						id_offs[i].build_id[j] & 0xff);
-				if (strstr(buf, build_id) != NULL)
+				if (memcmp(buf, id_offs[i].build_id, build_id_size) == 0)
 					build_id_matches = 1;
 			}
 		prev_key = key;
diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
index f4ea1a215ce4..47558b0d7f66 100644
--- a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
+++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
@@ -28,11 +28,10 @@ void test_stacktrace_build_id_nmi(void)
 		.config = PERF_COUNT_HW_CPU_CYCLES,
 	};
 	__u32 key, prev_key, val, duration = 0;
-	char buf[256];
-	int i, j;
+	char buf[BPF_BUILD_ID_SIZE];
 	struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
-	int build_id_matches = 0;
-	int retry = 1;
+	int build_id_matches = 0, build_id_size;
+	int i, retry = 1;
 
 	attr.sample_freq = read_perf_max_sample_freq();
 
@@ -94,7 +93,8 @@ void test_stacktrace_build_id_nmi(void)
 		  "err %d errno %d\n", err, errno))
 		goto cleanup;
 
-	err = extract_build_id(buf, 256);
+	build_id_size = read_build_id("urandom_read", buf, sizeof(buf));
+	err = build_id_size < 0 ? build_id_size : 0;
 
 	if (CHECK(err, "get build_id with readelf",
 		  "err %d errno %d\n", err, errno))
@@ -106,8 +106,6 @@ void test_stacktrace_build_id_nmi(void)
 		goto cleanup;
 
 	do {
-		char build_id[64];
-
 		err = bpf_map__lookup_elem(skel->maps.stackmap, &key, sizeof(key),
 					   id_offs, sizeof(id_offs), 0);
 		if (CHECK(err, "lookup_elem from stackmap",
@@ -116,10 +114,7 @@ void test_stacktrace_build_id_nmi(void)
 		for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
 			if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
 			    id_offs[i].offset != 0) {
-				for (j = 0; j < 20; ++j)
-					sprintf(build_id + 2 * j, "%02x",
-						id_offs[i].build_id[j] & 0xff);
-				if (strstr(buf, build_id) != NULL)
+				if (memcmp(buf, id_offs[i].build_id, build_id_size) == 0)
 					build_id_matches = 1;
 			}
 		prev_key = key;
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index d903e6a72a96..ea82921110da 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -629,31 +629,6 @@ int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len)
 	return err;
 }
 
-int extract_build_id(char *build_id, size_t size)
-{
-	FILE *fp;
-	char *line = NULL;
-	size_t len = 0;
-
-	fp = popen("readelf -n ./urandom_read | grep 'Build ID'", "r");
-	if (fp == NULL)
-		return -1;
-
-	if (getline(&line, &len, fp) == -1)
-		goto err;
-	pclose(fp);
-
-	if (len > size)
-		len = size;
-	memcpy(build_id, line, len);
-	build_id[len] = '\0';
-	free(line);
-	return 0;
-err:
-	pclose(fp);
-	return -1;
-}
-
 static int finit_module(int fd, const char *param_values, int flags)
 {
 	return syscall(__NR_finit_module, fd, param_values, flags);
diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
index 4b06b8347cd4..10ba43250668 100644
--- a/tools/testing/selftests/bpf/test_progs.h
+++ b/tools/testing/selftests/bpf/test_progs.h
@@ -405,7 +405,6 @@ static inline void *u64_to_ptr(__u64 ptr)
 int bpf_find_map(const char *test, struct bpf_object *obj, const char *name);
 int compare_map_keys(int map1_fd, int map2_fd);
 int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len);
-int extract_build_id(char *build_id, size_t size);
 int kern_sync_rcu(void);
 int trigger_module_test_read(int read_sz);
 int trigger_module_test_write(int write_sz);
-- 
2.39.2


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function
  2023-03-31  9:31 [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function Jiri Olsa
                   ` (2 preceding siblings ...)
  2023-03-31  9:31 ` [PATCHv4 bpf-next 3/3] selftests/bpf: Replace extract_build_id with read_build_id Jiri Olsa
@ 2023-03-31 16:50 ` patchwork-bot+netdevbpf
  3 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-03-31 16:50 UTC (permalink / raw)
  To: Jiri Olsa
  Cc: ast, daniel, andrii, bpf, kafai, songliubraving, yhs,
	john.fastabend, kpsingh, sdf, haoluo

Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Fri, 31 Mar 2023 11:31:54 +0200 you wrote:
> hi,
> this selftests cleanup was previously posted as part of file build id changes [1],
> which might take more time, so I'm sending the selftests changes separately so it
> won't get stuck.
> 
> v4 changes:
>   - added size argument to read_build_id [Andrii]
>   - condition changes in parse_build_id_buf [Andrii]
>   - use ELF_C_READ_MMAP in elf_begin [Andrii]
>   - return -ENOENT in read_build_id if build id is not found [Andrii]
>   - dropped elf class check [Andrii]
> 
> [...]

Here is the summary with links:
  - [PATCHv4,bpf-next,1/3] selftests/bpf: Add err.h header
    https://git.kernel.org/bpf/bpf-next/c/328bafc9a373
  - [PATCHv4,bpf-next,2/3] selftests/bpf: Add read_build_id function
    https://git.kernel.org/bpf/bpf-next/c/88dc8b3605b3
  - [PATCHv4,bpf-next,3/3] selftests/bpf: Replace extract_build_id with read_build_id
    https://git.kernel.org/bpf/bpf-next/c/dcc46f51d770

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



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2023-03-31  9:31 [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function Jiri Olsa
2023-03-31  9:31 ` [PATCHv4 bpf-next 1/3] selftests/bpf: Add err.h header Jiri Olsa
2023-03-31  9:31 ` [PATCHv4 bpf-next 2/3] selftests/bpf: Add read_build_id function Jiri Olsa
2023-03-31  9:31 ` [PATCHv4 bpf-next 3/3] selftests/bpf: Replace extract_build_id with read_build_id Jiri Olsa
2023-03-31 16:50 ` [PATCHv4 bpf-next 0/3] selftests/bpf: Add read_build_id function patchwork-bot+netdevbpf

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