The bpf_program__attach of libbpf(using bpf_link) is much more intuitive
than the previous method using ioctl.
bpf_program__attach_perf_event manages the enable of perf_event and
attach of BPF programs to it, so there's no neeed to do this
directly with ioctl.
In addition, bpf_link provides consistency in the use of API because it
allows disable (detach, destroy) for multiple events to be treated as
one bpf_link__destroy.
This commit refactors samples that attach the bpf program to perf_event
by using libbbpf instead of ioctl. Also the bpf_load in the samples were
removed and migrated to use libbbpf API.
Signed-off-by: Daniel T. Lee <danieltimlee@xxxxxxxxx>
---
samples/bpf/Makefile | 4 +--
samples/bpf/sampleip_user.c | 58 ++++++++++++++++++++++------------
samples/bpf/trace_event_user.c | 57 ++++++++++++++++++++++-----------
3 files changed, 78 insertions(+), 41 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index ff0061467dd3..424f6fe7ce38 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -88,8 +88,8 @@ 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_user.o
-trace_event-objs := bpf_load.o trace_event_user.o $(TRACE_HELPERS)
-sampleip-objs := bpf_load.o sampleip_user.o $(TRACE_HELPERS)
+trace_event-objs := trace_event_user.o $(TRACE_HELPERS)
+sampleip-objs := sampleip_user.o $(TRACE_HELPERS)
tc_l2_redirect-objs := bpf_load.o tc_l2_redirect_user.o
lwt_len_hist-objs := bpf_load.o lwt_len_hist_user.o
xdp_tx_iptunnel-objs := xdp_tx_iptunnel_user.o
diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
index b0f115f938bc..8a94ff558b17 100644
--- a/samples/bpf/sampleip_user.c
+++ b/samples/bpf/sampleip_user.c
@@ -10,13 +10,11 @@
#include <errno.h>
#include <signal.h>
#include <string.h>
-#include <assert.h>
#include <linux/perf_event.h>
#include <linux/ptrace.h>
#include <linux/bpf.h>
-#include <sys/ioctl.h>
+#include <bpf/bpf.h>
#include <bpf/libbpf.h>
-#include "bpf_load.h"
#include "perf-sys.h"
#include "trace_helpers.h"
@@ -25,6 +23,7 @@
#define MAX_IPS 8192
#define PAGE_OFFSET 0xffff880000000000
+static int map_fd;
static int nr_cpus;
static void usage(void)
@@ -34,7 +33,8 @@ static void usage(void)
printf(" duration # sampling duration (seconds), default 5\n");
}
-static int sampling_start(int *pmu_fd, int freq)
+static int sampling_start(int *pmu_fd, int freq, struct bpf_program *prog,
+ struct bpf_link **link)
{
int i;
@@ -53,20 +53,22 @@ static int sampling_start(int *pmu_fd, int freq)
fprintf(stderr, "ERROR: Initializing perf sampling\n");
return 1;
}
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF,
- prog_fd[0]) == 0);
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
+ link[i] = bpf_program__attach_perf_event(prog, pmu_fd[i]);
+ if (link[i] < 0) {
+ fprintf(stderr, "ERROR: Attach perf event\n");
+ return 1;
+ }
}
return 0;
}
-static void sampling_end(int *pmu_fd)
+static void sampling_end(struct bpf_link **link)
{
int i;
for (i = 0; i < nr_cpus; i++)
- close(pmu_fd[i]);
+ bpf_link__destroy(link[i]);
}
struct ipcount {
@@ -128,14 +130,17 @@ static void print_ip_map(int fd)
static void int_exit(int sig)
{
printf("\n");
- print_ip_map(map_fd[0]);
+ print_ip_map(map_fd);
exit(0);
}
int main(int argc, char **argv)
{
+ int prog_fd, *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
+ struct bpf_program *prog;
+ struct bpf_object *obj;
+ struct bpf_link **link;
char filename[256];
- int *pmu_fd, opt, freq = DEFAULT_FREQ, secs = DEFAULT_SECS;
/* process arguments */
while ((opt = getopt(argc, argv, "F:h")) != -1) {
@@ -165,36 +170,47 @@ int main(int argc, char **argv)
/* create perf FDs for each CPU */
nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
pmu_fd = malloc(nr_cpus * sizeof(int));
- if (pmu_fd == NULL) {
- fprintf(stderr, "ERROR: malloc of pmu_fd\n");
+ link = malloc(nr_cpus * sizeof(struct bpf_link *));
+ if (pmu_fd == NULL || link == NULL) {
+ fprintf(stderr, "ERROR: malloc of pmu_fd/link\n");
return 1;
}
/* load BPF program */
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
- if (load_bpf_file(filename)) {
+ if (bpf_prog_load(filename, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd)) {
fprintf(stderr, "ERROR: loading BPF program (errno %d):\n",
errno);
- if (strcmp(bpf_log_buf, "") == 0)
- fprintf(stderr, "Try: ulimit -l unlimited\n");
- else
- fprintf(stderr, "%s", bpf_log_buf);
return 1;
}
+
+ prog = bpf_program__next(NULL, obj);
+ if (!prog) {
+ printf("finding a prog in obj file failed\n");
+ return 1;
+ }
+
+ map_fd = bpf_object__find_map_fd_by_name(obj, "ip_map");
+ if (map_fd < 0) {
+ printf("finding a ip_map map in obj file failed\n");
+ return 1;
+ }
+
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
/* do sampling */
printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",
freq, secs);
- if (sampling_start(pmu_fd, freq) != 0)
+ if (sampling_start(pmu_fd, freq, prog, link) != 0)
return 1;
sleep(secs);
- sampling_end(pmu_fd);
+ sampling_end(link);
free(pmu_fd);
+ free(link);
/* output sample counts */
- print_ip_map(map_fd[0]);
+ print_ip_map(map_fd);
return 0;
}
diff --git a/samples/bpf/trace_event_user.c b/samples/bpf/trace_event_user.c
index 356171bc392b..fb5c7b91e74c 100644
--- a/samples/bpf/trace_event_user.c
+++ b/samples/bpf/trace_event_user.c
@@ -6,22 +6,21 @@
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
-#include <fcntl.h>
-#include <poll.h>
-#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <signal.h>
-#include <assert.h>
#include <errno.h>
#include <sys/resource.h>
+#include <bpf/bpf.h>
#include <bpf/libbpf.h>
-#include "bpf_load.h"
#include "perf-sys.h"
#include "trace_helpers.h"
#define SAMPLE_FREQ 50
+/* counts, stackmap */
+static int map_fd[2];
+struct bpf_program *prog;
static bool sys_read_seen, sys_write_seen;
static void print_ksym(__u64 addr)
@@ -137,6 +136,7 @@ static inline int generate_load(void)
static void test_perf_event_all_cpu(struct perf_event_attr *attr)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+ struct bpf_link **link = malloc(nr_cpus * sizeof(struct bpf_link *));
int *pmu_fd = malloc(nr_cpus * sizeof(int));
int i, error = 0;
@@ -151,8 +151,12 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
error = 1;
goto all_cpu_err;
}
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
- assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
+ link[i] = bpf_program__attach_perf_event(prog, pmu_fd[i]);
+ if (link[i] < 0) {
+ printf("bpf_program__attach_perf_event failed\n");
+ error = 1;
+ goto all_cpu_err;
+ }
}
if (generate_load() < 0) {
@@ -161,11 +165,11 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
}
print_stacks();
all_cpu_err:
- for (i--; i >= 0; i--) {
- ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
- close(pmu_fd[i]);
- }
+ for (i--; i >= 0; i--)
+ bpf_link__destroy(link[i]);
+
free(pmu_fd);
+ free(link);
if (error)
int_exit(0);
}
@@ -173,6 +177,7 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
static void test_perf_event_task(struct perf_event_attr *attr)
{
int pmu_fd, error = 0;
+ struct bpf_link *link;
/* per task perf event, enable inherit so the "dd ..." command can be traced properly.
* Enabling inherit will cause bpf_perf_prog_read_time helper failure.
@@ -185,8 +190,12 @@ static void test_perf_event_task(struct perf_event_attr *attr)
printf("sys_perf_event_open failed\n");
int_exit(0);
}
- assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
- assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
+ link = bpf_program__attach_perf_event(prog, pmu_fd);
+ if (link < 0) {
+ printf("bpf_program__attach_perf_event failed\n");
+ close(pmu_fd);
+ int_exit(0);
+ }
if (generate_load() < 0) {
error = 1;
@@ -194,8 +203,7 @@ static void test_perf_event_task(struct perf_event_attr *attr)
}
print_stacks();
err:
- ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
- close(pmu_fd);
+ bpf_link__destroy(link);
if (error)
int_exit(0);
}
@@ -282,7 +290,9 @@ static void test_bpf_perf_event(void)
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+ struct bpf_object *obj;
char filename[256];
+ int prog_fd;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
setrlimit(RLIMIT_MEMLOCK, &r);
@@ -295,9 +305,20 @@ int main(int argc, char **argv)
return 1;
}
- if (load_bpf_file(filename)) {
- printf("%s", bpf_log_buf);
- return 2;
+ if (bpf_prog_load(filename, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd))
+ return 1;
+
+ prog = bpf_program__next(NULL, obj);
+ if (!prog) {
+ printf("finding a prog in obj file failed\n");
+ return 1;
+ }
+
+ 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) {
+ printf("finding a counts/stackmap map in obj file failed\n");
+ return 1;
}
if (fork() == 0) {
--
2.25.1
