Currently, the kprobe BPF program attachment method for bpf_load is
quite old. The implementation of bpf_load "directly" controls and
manages(create, delete) the kprobe events of DEBUGFS. On the other hand,
using using the libbpf automatically manages the kprobe event.
(under bpf_link interface)
By calling bpf_program__attach(_kprobe) in libbpf, the corresponding
kprobe is created and the BPF program will be attached to this kprobe.
To remove this, by simply invoking bpf_link__destroy will clean up the
event.
This commit refactors kprobe tracing programs (tracex{1~7}_user.c) with
libbpf using bpf_link interface and bpf_program__attach.
tracex2_kern.c, which tracks system calls (sys_*), has been modified to
append prefix depending on architecture.
Signed-off-by: Daniel T. Lee <danieltimlee@xxxxxxxxx>
---
Changes in V2:
- refactor pointer error check with libbpf_get_error
- on bpf object open failure, return instead jump to cleanup
- add macro for adding architecture prefix to system calls (sys_*)
samples/bpf/Makefile | 12 ++++----
samples/bpf/trace_common.h | 13 ++++++++
samples/bpf/tracex1_user.c | 37 ++++++++++++++++++-----
samples/bpf/tracex2_kern.c | 3 +-
samples/bpf/tracex2_user.c | 51 +++++++++++++++++++++++++------
samples/bpf/tracex3_user.c | 61 ++++++++++++++++++++++++++++----------
samples/bpf/tracex4_user.c | 51 ++++++++++++++++++++++++-------
samples/bpf/tracex6_user.c | 49 ++++++++++++++++++++++++++----
samples/bpf/tracex7_user.c | 39 +++++++++++++++++++-----
9 files changed, 252 insertions(+), 64 deletions(-)
create mode 100644 samples/bpf/trace_common.h
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 424f6fe7ce38..4c91e5914329 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -64,13 +64,13 @@ fds_example-objs := fds_example.o
sockex1-objs := sockex1_user.o
sockex2-objs := sockex2_user.o
sockex3-objs := bpf_load.o sockex3_user.o
-tracex1-objs := bpf_load.o tracex1_user.o $(TRACE_HELPERS)
-tracex2-objs := bpf_load.o tracex2_user.o
-tracex3-objs := bpf_load.o tracex3_user.o
-tracex4-objs := bpf_load.o tracex4_user.o
+tracex1-objs := tracex1_user.o $(TRACE_HELPERS)
+tracex2-objs := tracex2_user.o
+tracex3-objs := tracex3_user.o
+tracex4-objs := tracex4_user.o
tracex5-objs := bpf_load.o tracex5_user.o $(TRACE_HELPERS)
-tracex6-objs := bpf_load.o tracex6_user.o
-tracex7-objs := bpf_load.o tracex7_user.o
+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
diff --git a/samples/bpf/trace_common.h b/samples/bpf/trace_common.h
new file mode 100644
index 000000000000..8cb5400aed1f
--- /dev/null
+++ b/samples/bpf/trace_common.h
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef __TRACE_COMMON_H
+#define __TRACE_COMMON_H
+
+#ifdef __x86_64__
+#define SYSCALL(SYS) "__x64_" __stringify(SYS)
+#elif defined(__s390x__)
+#define SYSCALL(SYS) "__s390x_" __stringify(SYS)
+#else
+#define SYSCALL(SYS) __stringify(SYS)
+#endif
+
+#endif
diff --git a/samples/bpf/tracex1_user.c b/samples/bpf/tracex1_user.c
index 55fddbd08702..9d4adb7fd834 100644
--- a/samples/bpf/tracex1_user.c
+++ b/samples/bpf/tracex1_user.c
@@ -1,21 +1,41 @@
// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
-#include <linux/bpf.h>
#include <unistd.h>
-#include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
#include "trace_helpers.h"
int main(int ac, char **argv)
{
- FILE *f;
+ struct bpf_link *link = NULL;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
char filename[256];
+ FILE *f;
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 (!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;
+ }
- 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;
}
f = popen("taskset 1 ping -c5 localhost", "r");
@@ -23,5 +43,8 @@ int main(int ac, char **argv)
read_trace_pipe();
+cleanup:
+ bpf_link__destroy(link);
+ bpf_object__close(obj);
return 0;
}
diff --git a/samples/bpf/tracex2_kern.c b/samples/bpf/tracex2_kern.c
index d865bb309bcb..cc5f94c098f8 100644
--- a/samples/bpf/tracex2_kern.c
+++ b/samples/bpf/tracex2_kern.c
@@ -10,6 +10,7 @@
#include <uapi/linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
+#include "trace_common.h"
struct bpf_map_def SEC("maps") my_map = {
.type = BPF_MAP_TYPE_HASH,
@@ -77,7 +78,7 @@ struct bpf_map_def SEC("maps") my_hist_map = {
.max_entries = 1024,
};
-SEC("kprobe/sys_write")
+SEC("kprobe/" SYSCALL(sys_write))
int bpf_prog3(struct pt_regs *ctx)
{
long write_size = PT_REGS_PARM3(ctx);
diff --git a/samples/bpf/tracex2_user.c b/samples/bpf/tracex2_user.c
index c9544a4ce61a..3e36b3e4e3ef 100644
--- a/samples/bpf/tracex2_user.c
+++ b/samples/bpf/tracex2_user.c
@@ -3,17 +3,19 @@
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
-#include <linux/bpf.h>
#include <string.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
#include "bpf_util.h"
#define MAX_INDEX 64
#define MAX_STARS 38
+/* my_map, my_hist_map */
+static int map_fd[2];
+
static void stars(char *str, long val, long max, int width)
{
int i;
@@ -115,18 +117,39 @@ static void int_exit(int sig)
int main(int ac, char **argv)
{
struct rlimit r = {1024*1024, RLIM_INFINITY};
- char filename[256];
long key, next_key, value;
+ struct bpf_link *links[2];
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ char filename[256];
+ int i, j = 0;
FILE *f;
- int i;
-
- snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK)");
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");
+ return 0;
+ }
+
+ /* 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, "my_map");
+ map_fd[1] = bpf_object__find_map_fd_by_name(obj, "my_hist_map");
+ 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);
@@ -138,9 +161,14 @@ int main(int ac, char **argv)
f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r");
(void) f;
- if (load_bpf_file(filename)) {
- printf("%s", bpf_log_buf);
- return 1;
+ bpf_object__for_each_program(prog, obj) {
+ links[j] = bpf_program__attach(prog);
+ if (libbpf_get_error(links[j])) {
+ fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+ links[j] = NULL;
+ goto cleanup;
+ }
+ j++;
}
for (i = 0; i < 5; i++) {
@@ -156,5 +184,10 @@ int main(int ac, char **argv)
}
print_hist(map_fd[1]);
+cleanup:
+ for (j--; j >= 0; j--)
+ bpf_link__destroy(links[j]);
+
+ bpf_object__close(obj);
return 0;
}
diff --git a/samples/bpf/tracex3_user.c b/samples/bpf/tracex3_user.c
index cf8fedc773f2..70e987775c15 100644
--- a/samples/bpf/tracex3_user.c
+++ b/samples/bpf/tracex3_user.c
@@ -7,11 +7,10 @@
#include <unistd.h>
#include <stdbool.h>
#include <string.h>
-#include <linux/bpf.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
#include "bpf_util.h"
#define SLOTS 100
@@ -109,20 +108,11 @@ static void print_hist(int fd)
int main(int ac, char **argv)
{
struct rlimit r = {1024*1024, RLIM_INFINITY};
+ struct bpf_link *links[2];
+ struct bpf_program *prog;
+ struct bpf_object *obj;
char filename[256];
- int i;
-
- snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
-
- if (setrlimit(RLIMIT_MEMLOCK, &r)) {
- perror("setrlimit(RLIMIT_MEMLOCK)");
- return 1;
- }
-
- if (load_bpf_file(filename)) {
- printf("%s", bpf_log_buf);
- return 1;
- }
+ int map_fd, i, j = 0;
for (i = 1; i < ac; i++) {
if (strcmp(argv[i], "-a") == 0) {
@@ -137,6 +127,40 @@ int main(int ac, char **argv)
}
}
+ if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+ perror("setrlimit(RLIMIT_MEMLOCK)");
+ 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");
+ return 0;
+ }
+
+ /* 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, "lat_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) {
+ links[j] = bpf_program__attach(prog);
+ if (libbpf_get_error(links[j])) {
+ fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+ links[j] = NULL;
+ goto cleanup;
+ }
+ j++;
+ }
+
printf(" heatmap of IO latency\n");
if (text_only)
printf(" %s", sym[num_colors - 1]);
@@ -153,9 +177,14 @@ int main(int ac, char **argv)
for (i = 0; ; i++) {
if (i % 20 == 0)
print_banner();
- print_hist(map_fd[1]);
+ print_hist(map_fd);
sleep(2);
}
+cleanup:
+ for (j--; j >= 0; j--)
+ bpf_link__destroy(links[j]);
+
+ bpf_object__close(obj);
return 0;
}
diff --git a/samples/bpf/tracex4_user.c b/samples/bpf/tracex4_user.c
index ec52203fce39..e8faf8f184ae 100644
--- a/samples/bpf/tracex4_user.c
+++ b/samples/bpf/tracex4_user.c
@@ -8,11 +8,10 @@
#include <stdbool.h>
#include <string.h>
#include <time.h>
-#include <linux/bpf.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
-#include "bpf_load.h"
+#include <bpf/libbpf.h>
struct pair {
long long val;
@@ -36,8 +35,8 @@ static void print_old_objects(int fd)
key = write(1, "\e[1;1H\e[2J", 12); /* clear screen */
key = -1;
- while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
- bpf_map_lookup_elem(map_fd[0], &next_key, &v);
+ while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
+ bpf_map_lookup_elem(fd, &next_key, &v);
key = next_key;
if (val - v.val < 1000000000ll)
/* object was allocated more then 1 sec ago */
@@ -50,25 +49,55 @@ static void print_old_objects(int fd)
int main(int ac, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ struct bpf_link *links[2];
+ struct bpf_program *prog;
+ struct bpf_object *obj;
char filename[256];
- int i;
-
- snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+ int map_fd, i, j = 0;
if (setrlimit(RLIMIT_MEMLOCK, &r)) {
perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)");
return 1;
}
- 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");
+ return 0;
+ }
+
+ /* 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) {
+ links[j] = bpf_program__attach(prog);
+ if (libbpf_get_error(links[j])) {
+ fprintf(stderr, "ERROR: bpf_program__attach failed\n");
+ links[j] = NULL;
+ goto cleanup;
+ }
+ j++;
}
for (i = 0; ; i++) {
- print_old_objects(map_fd[1]);
+ print_old_objects(map_fd);
sleep(1);
}
+cleanup:
+ for (j--; j >= 0; j--)
+ bpf_link__destroy(links[j]);
+
+ bpf_object__close(obj);
return 0;
}
diff --git a/samples/bpf/tracex6_user.c b/samples/bpf/tracex6_user.c
index 4bb3c830adb2..33df9784775d 100644
--- a/samples/bpf/tracex6_user.c
+++ b/samples/bpf/tracex6_user.c
@@ -4,7 +4,6 @@
#include <assert.h>
#include <fcntl.h>
#include <linux/perf_event.h>
-#include <linux/bpf.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
@@ -15,12 +14,15 @@
#include <sys/wait.h>
#include <unistd.h>
-#include "bpf_load.h"
#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
#include "perf-sys.h"
#define SAMPLE_PERIOD 0x7fffffffffffffffULL
+/* counters, values, values2 */
+static int map_fd[3];
+
static void check_on_cpu(int cpu, struct perf_event_attr *attr)
{
struct bpf_perf_event_value value2;
@@ -174,16 +176,51 @@ static void test_bpf_perf_event(void)
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ struct bpf_link *links[2];
+ struct bpf_program *prog;
+ struct bpf_object *obj;
char filename[256];
+ int i = 0;
+
+ setrlimit(RLIMIT_MEMLOCK, &r);
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;
+ }
- setrlimit(RLIMIT_MEMLOCK, &r);
- 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[0] = bpf_object__find_map_fd_by_name(obj, "counters");
+ map_fd[1] = bpf_object__find_map_fd_by_name(obj, "values");
+ map_fd[2] = bpf_object__find_map_fd_by_name(obj, "values2");
+ if (map_fd[0] < 0 || map_fd[1] < 0 || map_fd[2] < 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++;
}
test_bpf_perf_event();
+
+cleanup:
+ for (i--; i >= 0; i--)
+ bpf_link__destroy(links[i]);
+
+ bpf_object__close(obj);
return 0;
}
diff --git a/samples/bpf/tracex7_user.c b/samples/bpf/tracex7_user.c
index ea6dae78f0df..fdcd6580dd73 100644
--- a/samples/bpf/tracex7_user.c
+++ b/samples/bpf/tracex7_user.c
@@ -1,28 +1,51 @@
#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>
int main(int argc, char **argv)
{
- FILE *f;
+ struct bpf_link *link = NULL;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
char filename[256];
char command[256];
- int ret;
+ int ret = 0;
+ FILE *f;
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 (!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;
+ }
- 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;
}
snprintf(command, 256, "mount %s tmpmnt/", argv[1]);
f = popen(command, "r");
ret = pclose(f);
+cleanup:
+ bpf_link__destroy(link);
+ bpf_object__close(obj);
return ret ? 0 : 1;
}
--
2.25.1
