[PATCH bpf-next 0/3] samples: bpf: Refactor tracing programs with libbpf

STALE2191d

5 messages, 2 authors, 2020-08-25 · open the first message on its own page

[PATCH bpf-next 0/3] samples: bpf: Refactor tracing programs with libbpf

From: Daniel T. Lee <hidden>
Date: 2020-08-23 08:53:46 

For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
patch refactors the existing kprobe, tracepoint tracing programs with 
libbbpf bpf loader.

    - For kprobe events pointing to system calls, the SYSCALL() macro in
    trace_common.h was used.
    - Adding a kprobe/tracepoint event and attaching a bpf program to it
    was done through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Daniel T. Lee (3):
  samples: bpf: cleanup bpf_load.o from Makefile
  samples: bpf: Refactor kprobe tracing programs with libbpf
  samples: bpf: Refactor tracepoint tracing programs with libbpf

 samples/bpf/Makefile                          | 18 ++---
 samples/bpf/cpustat_kern.c                    | 36 +++++-----
 samples/bpf/cpustat_user.c                    | 47 +++++++++++--
 samples/bpf/lathist_kern.c                    | 24 +++----
 samples/bpf/lathist_user.c                    | 42 ++++++++++--
 samples/bpf/offwaketime_kern.c                | 52 +++++++-------
 samples/bpf/offwaketime_user.c                | 66 ++++++++++++++----
 samples/bpf/spintest_kern.c                   | 36 +++++-----
 samples/bpf/spintest_user.c                   | 68 +++++++++++++++----
 samples/bpf/syscall_tp_kern.c                 | 24 +++----
 samples/bpf/syscall_tp_user.c                 | 54 +++++++++++----
 .../bpf/test_current_task_under_cgroup_kern.c | 27 ++++----
 .../bpf/test_current_task_under_cgroup_user.c | 52 +++++++++++---
 samples/bpf/test_probe_write_user_kern.c      | 12 ++--
 samples/bpf/test_probe_write_user_user.c      | 49 ++++++++++---
 samples/bpf/trace_output_kern.c               | 15 ++--
 samples/bpf/trace_output_user.c               | 55 ++++++++++-----
 17 files changed, 465 insertions(+), 212 deletions(-)

-- 
2.25.1

[PATCH bpf-next 1/3] samples: bpf: cleanup bpf_load.o from Makefile

From: Daniel T. Lee <hidden>
Date: 2020-08-23 08:53:52 

Since commit cc7f641d637b ("samples: bpf: Refactor BPF map performance
test with libbpf") has ommited the removal of bpf_load.o from Makefile,
this commit removes the bpf_load.o rule for targets where bpf_load.o is
not used.

Fixes: cc7f641d637b ("samples: bpf: Refactor BPF map performance test with libbpf")
Signed-off-by: Daniel T. Lee <redacted>
---
 samples/bpf/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index f87ee02073ba..0cac89230c6d 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -76,7 +76,7 @@ trace_output-objs := bpf_load.o trace_output_user.o $(TRACE_HELPERS)
 lathist-objs := bpf_load.o lathist_user.o
 offwaketime-objs := bpf_load.o offwaketime_user.o $(TRACE_HELPERS)
 spintest-objs := bpf_load.o spintest_user.o $(TRACE_HELPERS)
-map_perf_test-objs := bpf_load.o map_perf_test_user.o
+map_perf_test-objs := map_perf_test_user.o
 test_overhead-objs := bpf_load.o test_overhead_user.o
 test_cgrp2_array_pin-objs := test_cgrp2_array_pin.o
 test_cgrp2_attach-objs := test_cgrp2_attach.o
-- 
2.25.1

[PATCH bpf-next 2/3] samples: bpf: Refactor kprobe tracing programs with libbpf

From: Daniel T. Lee <hidden>
Date: 2020-08-23 08:53:58 

For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing kprobe tracing programs with libbbpf
bpf loader.

    - For kprobe events pointing to system calls, the SYSCALL() macro in
    trace_common.h was used.
    - Adding a kprobe event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <redacted>
---
 samples/bpf/Makefile                          | 10 +--
 samples/bpf/lathist_kern.c                    | 24 +++----
 samples/bpf/lathist_user.c                    | 42 ++++++++++--
 samples/bpf/spintest_kern.c                   | 36 +++++-----
 samples/bpf/spintest_user.c                   | 68 +++++++++++++++----
 .../bpf/test_current_task_under_cgroup_kern.c | 27 ++++----
 .../bpf/test_current_task_under_cgroup_user.c | 52 +++++++++++---
 samples/bpf/test_probe_write_user_kern.c      | 12 ++--
 samples/bpf/test_probe_write_user_user.c      | 49 ++++++++++---
 samples/bpf/trace_output_kern.c               | 15 ++--
 samples/bpf/trace_output_user.c               | 55 ++++++++++-----
 11 files changed, 272 insertions(+), 118 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 0cac89230c6d..c74d477474e2 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -71,11 +71,11 @@ tracex4-objs := tracex4_user.o
 tracex5-objs := tracex5_user.o $(TRACE_HELPERS)
 tracex6-objs := tracex6_user.o
 tracex7-objs := tracex7_user.o
-test_probe_write_user-objs := bpf_load.o test_probe_write_user_user.o
-trace_output-objs := bpf_load.o trace_output_user.o $(TRACE_HELPERS)
-lathist-objs := bpf_load.o lathist_user.o
+test_probe_write_user-objs := test_probe_write_user_user.o
+trace_output-objs := trace_output_user.o $(TRACE_HELPERS)
+lathist-objs := lathist_user.o
 offwaketime-objs := bpf_load.o offwaketime_user.o $(TRACE_HELPERS)
-spintest-objs := bpf_load.o spintest_user.o $(TRACE_HELPERS)
+spintest-objs := spintest_user.o $(TRACE_HELPERS)
 map_perf_test-objs := map_perf_test_user.o
 test_overhead-objs := bpf_load.o test_overhead_user.o
 test_cgrp2_array_pin-objs := test_cgrp2_array_pin.o
@@ -86,7 +86,7 @@ xdp1-objs := xdp1_user.o
 # reuse xdp1 source intentionally
 xdp2-objs := xdp1_user.o
 xdp_router_ipv4-objs := xdp_router_ipv4_user.o
-test_current_task_under_cgroup-objs := bpf_load.o $(CGROUP_HELPERS) \
+test_current_task_under_cgroup-objs := $(CGROUP_HELPERS) \
 				       test_current_task_under_cgroup_user.o
 trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
 sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
diff --git a/samples/bpf/lathist_kern.c b/samples/bpf/lathist_kern.c
index ca9c2e4e69aa..4adfcbbe6ef4 100644
--- a/samples/bpf/lathist_kern.c
+++ b/samples/bpf/lathist_kern.c
@@ -18,12 +18,12 @@
  * trace_preempt_[on|off] tracepoints hooks is not supported.
  */
 
-struct bpf_map_def SEC("maps") my_map = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(int),
-	.value_size = sizeof(u64),
-	.max_entries = MAX_CPU,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, u64);
+	__uint(max_entries, MAX_CPU);
+} my_map SEC(".maps");
 
 SEC("kprobe/trace_preempt_off")
 int bpf_prog1(struct pt_regs *ctx)
@@ -61,12 +61,12 @@ static unsigned int log2l(unsigned long v)
 		return log2(v);
 }
 
-struct bpf_map_def SEC("maps") my_lat = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(int),
-	.value_size = sizeof(long),
-	.max_entries = MAX_CPU * MAX_ENTRIES,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, long);
+	__uint(max_entries, MAX_CPU * MAX_ENTRIES);
+} my_lat SEC(".maps");
 
 SEC("kprobe/trace_preempt_on")
 int bpf_prog2(struct pt_regs *ctx)
diff --git a/samples/bpf/lathist_user.c b/samples/bpf/lathist_user.c
index 2ff2839a52d5..7d8ff2418303 100644
--- a/samples/bpf/lathist_user.c
+++ b/samples/bpf/lathist_user.c
@@ -6,9 +6,8 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <signal.h>
-#include <linux/bpf.h>
+#include <bpf/libbpf.h>
 #include <bpf/bpf.h>
-#include "bpf_load.h"
 
 #define MAX_ENTRIES	20
 #define MAX_CPU		4
@@ -81,20 +80,51 @@ static void get_data(int fd)
 
 int main(int argc, char **argv)
 {
+	struct bpf_link *links[2];
+	struct bpf_program *prog;
+	struct bpf_object *obj;
 	char filename[256];
+	int map_fd, i = 0;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return 0;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	map_fd = bpf_object__find_map_fd_by_name(obj, "my_lat");
+	if (map_fd < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		links[i] = bpf_program__attach(prog);
+		if (libbpf_get_error(links[i])) {
+			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+			links[i] = NULL;
+			goto cleanup;
+		}
+		i++;
 	}
 
 	while (1) {
-		get_data(map_fd[1]);
+		get_data(map_fd);
 		print_hist();
 		sleep(5);
 	}
 
+cleanup:
+	for (i--; i >= 0; i--)
+		bpf_link__destroy(links[i]);
+
+	bpf_object__close(obj);
 	return 0;
 }
diff --git a/samples/bpf/spintest_kern.c b/samples/bpf/spintest_kern.c
index f508af357251..455da77319d9 100644
--- a/samples/bpf/spintest_kern.c
+++ b/samples/bpf/spintest_kern.c
@@ -12,25 +12,25 @@
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 
-struct bpf_map_def SEC("maps") my_map = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(long),
-	.value_size = sizeof(long),
-	.max_entries = 1024,
-};
-struct bpf_map_def SEC("maps") my_map2 = {
-	.type = BPF_MAP_TYPE_PERCPU_HASH,
-	.key_size = sizeof(long),
-	.value_size = sizeof(long),
-	.max_entries = 1024,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, long);
+	__type(value, long);
+	__uint(max_entries, 1024);
+} my_map SEC(".maps");
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+	__uint(key_size, sizeof(long));
+	__uint(value_size, sizeof(long));
+	__uint(max_entries, 1024);
+} my_map2 SEC(".maps");
 
-struct bpf_map_def SEC("maps") stackmap = {
-	.type = BPF_MAP_TYPE_STACK_TRACE,
-	.key_size = sizeof(u32),
-	.value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
-	.max_entries = 10000,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_STACK_TRACE);
+	__uint(key_size, sizeof(u32));
+	__uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));
+	__uint(max_entries, 10000);
+} stackmap SEC(".maps");
 
 #define PROG(foo) \
 int foo(struct pt_regs *ctx) \
diff --git a/samples/bpf/spintest_user.c b/samples/bpf/spintest_user.c
index fb430ea2ef51..847da9284fa8 100644
--- a/samples/bpf/spintest_user.c
+++ b/samples/bpf/spintest_user.c
@@ -1,40 +1,77 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
 #include <unistd.h>
-#include <linux/bpf.h>
 #include <string.h>
 #include <assert.h>
 #include <sys/resource.h>
 #include <bpf/libbpf.h>
-#include "bpf_load.h"
+#include <bpf/bpf.h>
 #include "trace_helpers.h"
 
 int main(int ac, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	char filename[256], symbol[256];
+	struct bpf_object *obj = NULL;
+	struct bpf_link *links[20];
 	long key, next_key, value;
-	char filename[256];
+	struct bpf_program *prog;
+	int map_fd, i, j = 0;
+	const char *title;
 	struct ksym *sym;
-	int i;
 
-	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-	setrlimit(RLIMIT_MEMLOCK, &r);
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK)");
+		return 1;
+	}
 
 	if (load_kallsyms()) {
 		printf("failed to process /proc/kallsyms\n");
 		return 2;
 	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		obj = NULL;
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd = bpf_object__find_map_fd_by_name(obj, "my_map");
+	if (map_fd < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		title = bpf_program__title(prog, false);
+		if (sscanf(title, "kprobe/%s", symbol) != 1)
+			continue;
+
+		/* Attach prog only when symbol exists */
+		if (ksym_get_addr(symbol)) {
+			links[j] = bpf_program__attach(prog);
+			if (libbpf_get_error(links[j])) {
+				fprintf(stderr, "bpf_program__attach failed\n");
+				links[j] = NULL;
+				goto cleanup;
+			}
+			j++;
+		}
 	}
 
 	for (i = 0; i < 5; i++) {
 		key = 0;
 		printf("kprobing funcs:");
-		while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
-			bpf_map_lookup_elem(map_fd[0], &next_key, &value);
+		while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0) {
+			bpf_map_lookup_elem(map_fd, &next_key, &value);
 			assert(next_key == value);
 			sym = ksym_search(value);
 			key = next_key;
@@ -48,10 +85,15 @@ int main(int ac, char **argv)
 		if (key)
 			printf("\n");
 		key = 0;
-		while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0)
-			bpf_map_delete_elem(map_fd[0], &next_key);
+		while (bpf_map_get_next_key(map_fd, &key, &next_key) == 0)
+			bpf_map_delete_elem(map_fd, &next_key);
 		sleep(1);
 	}
 
+cleanup:
+	for (j--; j >= 0; j--)
+		bpf_link__destroy(links[j]);
+
+	bpf_object__close(obj);
 	return 0;
 }
diff --git a/samples/bpf/test_current_task_under_cgroup_kern.c b/samples/bpf/test_current_task_under_cgroup_kern.c
index 6dc4f41bb6cb..fbd43e2bb4d3 100644
--- a/samples/bpf/test_current_task_under_cgroup_kern.c
+++ b/samples/bpf/test_current_task_under_cgroup_kern.c
@@ -10,23 +10,24 @@
 #include <linux/version.h>
 #include <bpf/bpf_helpers.h>
 #include <uapi/linux/utsname.h>
+#include "trace_common.h"
 
-struct bpf_map_def SEC("maps") cgroup_map = {
-	.type			= BPF_MAP_TYPE_CGROUP_ARRAY,
-	.key_size		= sizeof(u32),
-	.value_size		= sizeof(u32),
-	.max_entries	= 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
+	__uint(key_size, sizeof(u32));
+	__uint(value_size, sizeof(u32));
+	__uint(max_entries, 1);
+} cgroup_map SEC(".maps");
 
-struct bpf_map_def SEC("maps") perf_map = {
-	.type			= BPF_MAP_TYPE_ARRAY,
-	.key_size		= sizeof(u32),
-	.value_size		= sizeof(u64),
-	.max_entries	= 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u64);
+	__uint(max_entries, 1);
+} perf_map SEC(".maps");
 
 /* Writes the last PID that called sync to a map at index 0 */
-SEC("kprobe/sys_sync")
+SEC("kprobe/" SYSCALL(sys_sync))
 int bpf_prog1(struct pt_regs *ctx)
 {
 	u64 pid = bpf_get_current_pid_tgid();
diff --git a/samples/bpf/test_current_task_under_cgroup_user.c b/samples/bpf/test_current_task_under_cgroup_user.c
index 06e9f8ce42e2..ac251a417f45 100644
--- a/samples/bpf/test_current_task_under_cgroup_user.c
+++ b/samples/bpf/test_current_task_under_cgroup_user.c
@@ -4,10 +4,9 @@
 
 #define _GNU_SOURCE
 #include <stdio.h>
-#include <linux/bpf.h>
 #include <unistd.h>
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
 #include "cgroup_helpers.h"
 
 #define CGROUP_PATH		"/my-cgroup"
@@ -15,13 +14,44 @@
 int main(int argc, char **argv)
 {
 	pid_t remote_pid, local_pid = getpid();
-	int cg2, idx = 0, rc = 0;
+	struct bpf_link *link = NULL;
+	struct bpf_program *prog;
+	int cg2, idx = 0, rc = 1;
+	struct bpf_object *obj;
 	char filename[256];
+	int map_fd[2];
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return 0;
+	}
+
+	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
+	if (!prog) {
+		printf("finding a prog in obj file failed\n");
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "cgroup_map");
+	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "perf_map");
+	if (map_fd[0] < 0 || map_fd[1] < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	link = bpf_program__attach(prog);
+	if (libbpf_get_error(link)) {
+		fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+		link = NULL;
+		goto cleanup;
 	}
 
 	if (setup_cgroup_environment())
@@ -70,12 +100,14 @@ int main(int argc, char **argv)
 		goto err;
 	}
 
-	goto out;
-err:
-	rc = 1;
+	rc = 0;
 
-out:
+err:
 	close(cg2);
 	cleanup_cgroup_environment();
+
+cleanup:
+	bpf_link__destroy(link);
+	bpf_object__close(obj);
 	return rc;
 }
diff --git a/samples/bpf/test_probe_write_user_kern.c b/samples/bpf/test_probe_write_user_kern.c
index fd651a65281e..220a96438d75 100644
--- a/samples/bpf/test_probe_write_user_kern.c
+++ b/samples/bpf/test_probe_write_user_kern.c
@@ -13,12 +13,12 @@
 #include <bpf/bpf_core_read.h>
 #include "trace_common.h"
 
-struct bpf_map_def SEC("maps") dnat_map = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(struct sockaddr_in),
-	.value_size = sizeof(struct sockaddr_in),
-	.max_entries = 256,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, struct sockaddr_in);
+	__type(value, struct sockaddr_in);
+	__uint(max_entries, 256);
+} dnat_map SEC(".maps");
 
 /* kprobe is NOT a stable ABI
  * kernel functions can be removed, renamed or completely change semantics.
diff --git a/samples/bpf/test_probe_write_user_user.c b/samples/bpf/test_probe_write_user_user.c
index 045eb5e30f54..00ccfb834e45 100644
--- a/samples/bpf/test_probe_write_user_user.c
+++ b/samples/bpf/test_probe_write_user_user.c
@@ -1,21 +1,22 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
 #include <assert.h>
-#include <linux/bpf.h>
 #include <unistd.h>
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
 #include <sys/socket.h>
-#include <string.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
 int main(int ac, char **argv)
 {
-	int serverfd, serverconnfd, clientfd;
-	socklen_t sockaddr_len;
-	struct sockaddr serv_addr, mapped_addr, tmp_addr;
 	struct sockaddr_in *serv_addr_in, *mapped_addr_in, *tmp_addr_in;
+	struct sockaddr serv_addr, mapped_addr, tmp_addr;
+	int serverfd, serverconnfd, clientfd, map_fd;
+	struct bpf_link *link = NULL;
+	struct bpf_program *prog;
+	struct bpf_object *obj;
+	socklen_t sockaddr_len;
 	char filename[256];
 	char *ip;
 
@@ -24,10 +25,35 @@ int main(int ac, char **argv)
 	tmp_addr_in = (struct sockaddr_in *)&tmp_addr;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return 0;
+	}
+
+	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
+	if (libbpf_get_error(prog)) {
+		fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd = bpf_object__find_map_fd_by_name(obj, "dnat_map");
+	if (map_fd < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	link = bpf_program__attach(prog);
+	if (libbpf_get_error(link)) {
+		fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+		link = NULL;
+		goto cleanup;
 	}
 
 	assert((serverfd = socket(AF_INET, SOCK_STREAM, 0)) > 0);
@@ -51,7 +77,7 @@ int main(int ac, char **argv)
 	mapped_addr_in->sin_port = htons(5555);
 	mapped_addr_in->sin_addr.s_addr = inet_addr("255.255.255.255");
 
-	assert(!bpf_map_update_elem(map_fd[0], &mapped_addr, &serv_addr, BPF_ANY));
+	assert(!bpf_map_update_elem(map_fd, &mapped_addr, &serv_addr, BPF_ANY));
 
 	assert(listen(serverfd, 5) == 0);
 
@@ -75,5 +101,8 @@ int main(int ac, char **argv)
 	/* Is the server's getsockname = the socket getpeername */
 	assert(memcmp(&serv_addr, &tmp_addr, sizeof(struct sockaddr_in)) == 0);
 
+cleanup:
+	bpf_link__destroy(link);
+	bpf_object__close(obj);
 	return 0;
 }
diff --git a/samples/bpf/trace_output_kern.c b/samples/bpf/trace_output_kern.c
index 1d7d422cae6f..b64815af0943 100644
--- a/samples/bpf/trace_output_kern.c
+++ b/samples/bpf/trace_output_kern.c
@@ -2,15 +2,16 @@
 #include <linux/version.h>
 #include <uapi/linux/bpf.h>
 #include <bpf/bpf_helpers.h>
+#include "trace_common.h"
 
-struct bpf_map_def SEC("maps") my_map = {
-	.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
-	.key_size = sizeof(int),
-	.value_size = sizeof(u32),
-	.max_entries = 2,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+	__uint(key_size, sizeof(int));
+	__uint(value_size, sizeof(u32));
+	__uint(max_entries, 2);
+} my_map SEC(".maps");
 
-SEC("kprobe/sys_write")
+SEC("kprobe/" SYSCALL(sys_write))
 int bpf_prog1(struct pt_regs *ctx)
 {
 	struct S {
diff --git a/samples/bpf/trace_output_user.c b/samples/bpf/trace_output_user.c
index 60a17dd05345..364b98764d54 100644
--- a/samples/bpf/trace_output_user.c
+++ b/samples/bpf/trace_output_user.c
@@ -1,23 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #include <stdio.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <stdbool.h>
-#include <string.h>
 #include <fcntl.h>
 #include <poll.h>
-#include <linux/perf_event.h>
-#include <linux/bpf.h>
-#include <errno.h>
-#include <assert.h>
-#include <sys/syscall.h>
-#include <sys/ioctl.h>
-#include <sys/mman.h>
 #include <time.h>
 #include <signal.h>
 #include <bpf/libbpf.h>
-#include "bpf_load.h"
-#include "perf-sys.h"
 
 static __u64 time_get_ns(void)
 {
@@ -57,20 +44,48 @@ static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
 int main(int argc, char **argv)
 {
 	struct perf_buffer_opts pb_opts = {};
+	struct bpf_link *link = NULL;
+	struct bpf_program *prog;
 	struct perf_buffer *pb;
+	struct bpf_object *obj;
+	int map_fd, ret = 0;
 	char filename[256];
 	FILE *f;
-	int ret;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return 0;
+	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd = bpf_object__find_map_fd_by_name(obj, "my_map");
+	if (map_fd < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
+	if (libbpf_get_error(prog)) {
+		fprintf(stderr, "ERROR: finding a prog in obj file failed\n");
+		goto cleanup;
+	}
+
+	link = bpf_program__attach(prog);
+	if (libbpf_get_error(link)) {
+		fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+		link = NULL;
+		goto cleanup;
 	}
 
 	pb_opts.sample_cb = print_bpf_output;
-	pb = perf_buffer__new(map_fd[0], 8, &pb_opts);
+	pb = perf_buffer__new(map_fd, 8, &pb_opts);
 	ret = libbpf_get_error(pb);
 	if (ret) {
 		printf("failed to setup perf_buffer: %d\n", ret);
@@ -84,5 +99,9 @@ int main(int argc, char **argv)
 	while ((ret = perf_buffer__poll(pb, 1000)) >= 0 && cnt < MAX_CNT) {
 	}
 	kill(0, SIGINT);
+
+cleanup:
+	bpf_link__destroy(link);
+	bpf_object__close(obj);
 	return ret;
 }
-- 
2.25.1

[PATCH bpf-next 3/3] samples: bpf: Refactor tracepoint tracing programs with libbpf

From: Daniel T. Lee <hidden>
Date: 2020-08-23 08:54:02 

For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing tracepoint tracing programs with libbbpf
bpf loader.

    - Adding a tracepoint event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <redacted>
---
 samples/bpf/Makefile           |  6 ++--
 samples/bpf/cpustat_kern.c     | 36 +++++++++----------
 samples/bpf/cpustat_user.c     | 47 ++++++++++++++++++++----
 samples/bpf/offwaketime_kern.c | 52 +++++++++++++--------------
 samples/bpf/offwaketime_user.c | 66 ++++++++++++++++++++++++++--------
 samples/bpf/syscall_tp_kern.c  | 24 ++++++-------
 samples/bpf/syscall_tp_user.c  | 54 +++++++++++++++++++++-------
 7 files changed, 192 insertions(+), 93 deletions(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index c74d477474e2..a6d3646b3818 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -74,7 +74,7 @@ tracex7-objs := tracex7_user.o
 test_probe_write_user-objs := test_probe_write_user_user.o
 trace_output-objs := trace_output_user.o $(TRACE_HELPERS)
 lathist-objs := lathist_user.o
-offwaketime-objs := bpf_load.o offwaketime_user.o $(TRACE_HELPERS)
+offwaketime-objs := offwaketime_user.o $(TRACE_HELPERS)
 spintest-objs := spintest_user.o $(TRACE_HELPERS)
 map_perf_test-objs := map_perf_test_user.o
 test_overhead-objs := bpf_load.o test_overhead_user.o
@@ -100,8 +100,8 @@ xdp_redirect_map-objs := xdp_redirect_map_user.o
 xdp_redirect_cpu-objs := bpf_load.o xdp_redirect_cpu_user.o
 xdp_monitor-objs := bpf_load.o xdp_monitor_user.o
 xdp_rxq_info-objs := xdp_rxq_info_user.o
-syscall_tp-objs := bpf_load.o syscall_tp_user.o
-cpustat-objs := bpf_load.o cpustat_user.o
+syscall_tp-objs := syscall_tp_user.o
+cpustat-objs := cpustat_user.o
 xdp_adjust_tail-objs := xdp_adjust_tail_user.o
 xdpsock-objs := xdpsock_user.o
 xdp_fwd-objs := xdp_fwd_user.o
diff --git a/samples/bpf/cpustat_kern.c b/samples/bpf/cpustat_kern.c
index a86a19d5f033..5aefd19cdfa1 100644
--- a/samples/bpf/cpustat_kern.c
+++ b/samples/bpf/cpustat_kern.c
@@ -51,28 +51,28 @@ static int cpu_opps[] = { 208000, 432000, 729000, 960000, 1200000 };
 #define MAP_OFF_PSTATE_IDX	3
 #define MAP_OFF_NUM		4
 
-struct bpf_map_def SEC("maps") my_map = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(u64),
-	.max_entries = MAX_CPU * MAP_OFF_NUM,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u64);
+	__uint(max_entries, MAX_CPU * MAP_OFF_NUM);
+} my_map SEC(".maps");
 
 /* cstate_duration records duration time for every idle state per CPU */
-struct bpf_map_def SEC("maps") cstate_duration = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(u64),
-	.max_entries = MAX_CPU * MAX_CSTATE_ENTRIES,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u64);
+	__uint(max_entries, MAX_CPU * MAX_CSTATE_ENTRIES);
+} cstate_duration SEC(".maps");
 
 /* pstate_duration records duration time for every operating point per CPU */
-struct bpf_map_def SEC("maps") pstate_duration = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(u64),
-	.max_entries = MAX_CPU * MAX_PSTATE_ENTRIES,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u64);
+	__uint(max_entries, MAX_CPU * MAX_PSTATE_ENTRIES);
+} pstate_duration SEC(".maps");
 
 /*
  * The trace events for cpu_idle and cpu_frequency are taken from:
diff --git a/samples/bpf/cpustat_user.c b/samples/bpf/cpustat_user.c
index 869a99406dbf..96675985e9e0 100644
--- a/samples/bpf/cpustat_user.c
+++ b/samples/bpf/cpustat_user.c
@@ -9,7 +9,6 @@
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
-#include <linux/bpf.h>
 #include <locale.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -18,7 +17,9 @@
 #include <sys/wait.h>
 
 #include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
+
+static int cstate_map_fd, pstate_map_fd;
 
 #define MAX_CPU			8
 #define MAX_PSTATE_ENTRIES	5
@@ -181,21 +182,50 @@ static void int_exit(int sig)
 {
 	cpu_stat_inject_cpu_idle_event();
 	cpu_stat_inject_cpu_frequency_event();
-	cpu_stat_update(map_fd[1], map_fd[2]);
+	cpu_stat_update(cstate_map_fd, pstate_map_fd);
 	cpu_stat_print();
 	exit(0);
 }
 
 int main(int argc, char **argv)
 {
+	struct bpf_link *link = NULL;
+	struct bpf_program *prog;
+	struct bpf_object *obj;
 	char filename[256];
 	int ret;
 
 	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		return 0;
+	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
+	if (!prog) {
+		printf("finding a prog in obj file failed\n");
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	cstate_map_fd = bpf_object__find_map_fd_by_name(obj, "cstate_duration");
+	pstate_map_fd = bpf_object__find_map_fd_by_name(obj, "pstate_duration");
+	if (cstate_map_fd < 0 || pstate_map_fd < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	link = bpf_program__attach(prog);
+	if (libbpf_get_error(link)) {
+		fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+		link = NULL;
+		goto cleanup;
 	}
 
 	ret = cpu_stat_inject_cpu_idle_event();
@@ -210,10 +240,13 @@ int main(int argc, char **argv)
 	signal(SIGTERM, int_exit);
 
 	while (1) {
-		cpu_stat_update(map_fd[1], map_fd[2]);
+		cpu_stat_update(cstate_map_fd, pstate_map_fd);
 		cpu_stat_print();
 		sleep(5);
 	}
 
+cleanup:
+	bpf_link__destroy(link);
+	bpf_object__close(obj);
 	return 0;
 }
diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c
index e74ee1cd4b9c..14b792915a9c 100644
--- a/samples/bpf/offwaketime_kern.c
+++ b/samples/bpf/offwaketime_kern.c
@@ -28,38 +28,38 @@ struct key_t {
 	u32 tret;
 };
 
-struct bpf_map_def SEC("maps") counts = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(struct key_t),
-	.value_size = sizeof(u64),
-	.max_entries = 10000,
-};
-
-struct bpf_map_def SEC("maps") start = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(u64),
-	.max_entries = 10000,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, struct key_t);
+	__type(value, u64);
+	__uint(max_entries, 10000);
+} counts SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, u32);
+	__type(value, u64);
+	__uint(max_entries, 10000);
+} start SEC(".maps");
 
 struct wokeby_t {
 	char name[TASK_COMM_LEN];
 	u32 ret;
 };
 
-struct bpf_map_def SEC("maps") wokeby = {
-	.type = BPF_MAP_TYPE_HASH,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(struct wokeby_t),
-	.max_entries = 10000,
-};
-
-struct bpf_map_def SEC("maps") stackmap = {
-	.type = BPF_MAP_TYPE_STACK_TRACE,
-	.key_size = sizeof(u32),
-	.value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
-	.max_entries = 10000,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, u32);
+	__type(value, struct wokeby_t);
+	__uint(max_entries, 10000);
+} wokeby SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_STACK_TRACE);
+	__uint(key_size, sizeof(u32));
+	__uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));
+	__uint(max_entries, 10000);
+} stackmap SEC(".maps");
 
 #define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
 
diff --git a/samples/bpf/offwaketime_user.c b/samples/bpf/offwaketime_user.c
index 51c7da5341cc..5734cfdaaacb 100644
--- a/samples/bpf/offwaketime_user.c
+++ b/samples/bpf/offwaketime_user.c
@@ -5,19 +5,19 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <signal.h>
-#include <linux/bpf.h>
-#include <string.h>
 #include <linux/perf_event.h>
 #include <errno.h>
-#include <assert.h>
 #include <stdbool.h>
 #include <sys/resource.h>
 #include <bpf/libbpf.h>
-#include "bpf_load.h"
+#include <bpf/bpf.h>
 #include "trace_helpers.h"
 
 #define PRINT_RAW_ADDR 0
 
+/* counts, stackmap */
+static int map_fd[2];
+
 static void print_ksym(__u64 addr)
 {
 	struct ksym *sym;
@@ -52,14 +52,14 @@ static void print_stack(struct key_t *key, __u64 count)
 	int i;
 
 	printf("%s;", key->target);
-	if (bpf_map_lookup_elem(map_fd[3], &key->tret, ip) != 0) {
+	if (bpf_map_lookup_elem(map_fd[1], &key->tret, ip) != 0) {
 		printf("---;");
 	} else {
 		for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
 			print_ksym(ip[i]);
 	}
 	printf("-;");
-	if (bpf_map_lookup_elem(map_fd[3], &key->wret, ip) != 0) {
+	if (bpf_map_lookup_elem(map_fd[1], &key->wret, ip) != 0) {
 		printf("---;");
 	} else {
 		for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)
@@ -96,23 +96,54 @@ static void int_exit(int sig)
 int main(int argc, char **argv)
 {
 	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+	struct bpf_object *obj = NULL;
+	struct bpf_link *links[2];
+	struct bpf_program *prog;
+	int delay = 1, i = 0;
 	char filename[256];
-	int delay = 1;
-
-	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-	setrlimit(RLIMIT_MEMLOCK, &r);
 
-	signal(SIGINT, int_exit);
-	signal(SIGTERM, int_exit);
+	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+		perror("setrlimit(RLIMIT_MEMLOCK)");
+		return 1;
+	}
 
 	if (load_kallsyms()) {
 		printf("failed to process /proc/kallsyms\n");
 		return 2;
 	}
 
-	if (load_bpf_file(filename)) {
-		printf("%s", bpf_log_buf);
-		return 1;
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+	obj = bpf_object__open_file(filename, NULL);
+	if (libbpf_get_error(obj)) {
+		fprintf(stderr, "ERROR: opening BPF object file failed\n");
+		obj = NULL;
+		goto cleanup;
+	}
+
+	/* load BPF program */
+	if (bpf_object__load(obj)) {
+		fprintf(stderr, "ERROR: loading BPF object file failed\n");
+		goto cleanup;
+	}
+
+	map_fd[0] = bpf_object__find_map_fd_by_name(obj, "counts");
+	map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
+	if (map_fd[0] < 0 || map_fd[1] < 0) {
+		fprintf(stderr, "ERROR: finding a map in obj file failed\n");
+		goto cleanup;
+	}
+
+	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
+
+	bpf_object__for_each_program(prog, obj) {
+		links[i] = bpf_program__attach(prog);
+		if (libbpf_get_error(links[i])) {
+			fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+			links[i] = NULL;
+			goto cleanup;
+		}
+		i++;
 	}
 
 	if (argc > 1)
@@ -120,5 +151,10 @@ int main(int argc, char **argv)
 	sleep(delay);
 	print_stacks(map_fd[0]);
 
+cleanup:
+	for (i--; i >= 0; i--)
+		bpf_link__destroy(links[i]);
+
+	bpf_object__close(obj);
 	return 0;
 }
diff --git a/samples/bpf/syscall_tp_kern.c b/samples/bpf/syscall_tp_kern.c
index 5a62b03b1f88..50231c2eff9c 100644
--- a/samples/bpf/syscall_tp_kern.c
+++ b/samples/bpf/syscall_tp_kern.c
@@ -18,19 +18,19 @@ struct syscalls_exit_open_args {
 	long ret;
 };
 
-struct bpf_map_def SEC("maps") enter_open_map = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(u32),
-	.max_entries = 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u32);
+	__uint(max_entries, 1);
+} enter_open_map SEC(".maps");
 
-struct bpf_map_def SEC("maps") exit_open_map = {
-	.type = BPF_MAP_TYPE_ARRAY,
-	.key_size = sizeof(u32),
-	.value_size = sizeof(u32),
-	.max_entries = 1,
-};
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, u32);
+	__type(value, u32);
+	__uint(max_entries, 1);
+} exit_open_map SEC(".maps");
 
 static __always_inline void count(void *map)
 {
diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c
index 57014bab7cbe..76a1d00128fb 100644
--- a/samples/bpf/syscall_tp_user.c
+++ b/samples/bpf/syscall_tp_user.c
@@ -5,16 +5,12 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <stdlib.h>
-#include <signal.h>
-#include <linux/bpf.h>
 #include <string.h>
 #include <linux/perf_event.h>
 #include <errno.h>
-#include <assert.h>
-#include <stdbool.h>
 #include <sys/resource.h>
+#include <bpf/libbpf.h>
 #include <bpf/bpf.h>
-#include "bpf_load.h"
 
 /* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
  * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
@@ -49,16 +45,44 @@ static void verify_map(int map_id)
 
 static int test(char *filename, int num_progs)
 {
-	int i, fd, map0_fds[num_progs], map1_fds[num_progs];
+	int map0_fds[num_progs], map1_fds[num_progs], fd, i, j = 0;
+	struct bpf_link *links[num_progs * 4];
+	struct bpf_object *objs[num_progs];
+	struct bpf_program *prog;
 
 	for (i = 0; i < num_progs; i++) {
-		if (load_bpf_file(filename)) {
-			fprintf(stderr, "%s", bpf_log_buf);
-			return 1;
+		objs[i] = bpf_object__open_file(filename, NULL);
+		if (libbpf_get_error(objs[i])) {
+			fprintf(stderr, "opening BPF object file failed\n");
+			objs[i] = NULL;
+			goto cleanup;
 		}
-		printf("prog #%d: map ids %d %d\n", i, map_fd[0], map_fd[1]);
-		map0_fds[i] = map_fd[0];
-		map1_fds[i] = map_fd[1];
+
+		/* load BPF program */
+		if (bpf_object__load(objs[i])) {
+			fprintf(stderr, "loading BPF object file failed\n");
+			goto cleanup;
+		}
+
+		map0_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
+							      "enter_open_map");
+		map1_fds[i] = bpf_object__find_map_fd_by_name(objs[i],
+							      "exit_open_map");
+		if (map0_fds[i] < 0 || map1_fds[i] < 0) {
+			fprintf(stderr, "finding a map in obj file failed\n");
+			goto cleanup;
+		}
+
+		bpf_object__for_each_program(prog, objs[i]) {
+			links[j] = bpf_program__attach(prog);
+			if (libbpf_get_error(links[j])) {
+				fprintf(stderr, "bpf_program__attach failed\n");
+				links[j] = NULL;
+				goto cleanup;
+			}
+			j++;
+		}
+		printf("prog #%d: map ids %d %d\n", i, map0_fds[i], map1_fds[i]);
 	}
 
 	/* current load_bpf_file has perf_event_open default pid = -1
@@ -80,6 +104,12 @@ static int test(char *filename, int num_progs)
 		verify_map(map1_fds[i]);
 	}
 
+cleanup:
+	for (j--; j >= 0; j--)
+		bpf_link__destroy(links[j]);
+
+	for (i--; i >= 0; i--)
+		bpf_object__close(objs[i]);
 	return 0;
 }
 
-- 
2.25.1

Re: [PATCH bpf-next 0/3] samples: bpf: Refactor tracing programs with libbpf

From: Alexei Starovoitov <hidden>
Date: 2020-08-25 04:02:18 

On Sun, Aug 23, 2020 at 05:53:31PM +0900, Daniel T. Lee wrote:
For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
patch refactors the existing kprobe, tracepoint tracing programs with 
libbbpf bpf loader.
Thank for you doing the conversion. Applied.
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