summaryrefslogtreecommitdiffstats
path: root/samples/bpf/syscall_tp_user.c
diff options
context:
space:
mode:
Diffstat (limited to 'samples/bpf/syscall_tp_user.c')
-rw-r--r--samples/bpf/syscall_tp_user.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c
new file mode 100644
index 0000000000..7a09ac74fa
--- /dev/null
+++ b/samples/bpf/syscall_tp_user.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2017 Facebook
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <linux/perf_event.h>
+#include <errno.h>
+#include <bpf/libbpf.h>
+#include <bpf/bpf.h>
+
+/* This program verifies bpf attachment to tracepoint sys_enter_* and sys_exit_*.
+ * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
+ */
+
+static void usage(const char *cmd)
+{
+ printf("USAGE: %s [-i nr_tests] [-h]\n", cmd);
+ printf(" -i nr_tests # rounds of test to run\n");
+ printf(" -h # help\n");
+}
+
+static void verify_map(int map_id)
+{
+ __u32 key = 0;
+ __u32 val;
+
+ if (bpf_map_lookup_elem(map_id, &key, &val) != 0) {
+ fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
+ return;
+ }
+ if (val == 0) {
+ fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
+ return;
+ }
+
+ printf("verify map:%d val: %d\n", map_id, val);
+
+ val = 0;
+ if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
+ fprintf(stderr, "map_update failed: %s\n", strerror(errno));
+ return;
+ }
+}
+
+static int test(char *filename, int nr_tests)
+{
+ int map0_fds[nr_tests], map1_fds[nr_tests], fd, i, j = 0;
+ struct bpf_link **links = NULL;
+ struct bpf_object *objs[nr_tests];
+ struct bpf_program *prog;
+
+ for (i = 0; i < nr_tests; i++) {
+ 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;
+ }
+
+ /* One-time initialization */
+ if (!links) {
+ int nr_progs = 0;
+
+ bpf_object__for_each_program(prog, objs[i])
+ nr_progs += 1;
+
+ links = calloc(nr_progs * nr_tests, sizeof(struct bpf_link *));
+
+ if (!links)
+ goto cleanup;
+ }
+
+ /* 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
+ * and cpu = 0, which permits attached bpf execution on
+ * all cpus for all pid's. bpf program execution ignores
+ * cpu affinity.
+ */
+ /* trigger some "open" operations */
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ fprintf(stderr, "open failed: %s\n", strerror(errno));
+ return 1;
+ }
+ close(fd);
+
+ /* verify the map */
+ for (i = 0; i < nr_tests; i++) {
+ verify_map(map0_fds[i]);
+ verify_map(map1_fds[i]);
+ }
+
+cleanup:
+ if (links) {
+ for (j--; j >= 0; j--)
+ bpf_link__destroy(links[j]);
+
+ free(links);
+ }
+
+ for (i--; i >= 0; i--)
+ bpf_object__close(objs[i]);
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int opt, nr_tests = 1;
+ char filename[256];
+
+ while ((opt = getopt(argc, argv, "i:h")) != -1) {
+ switch (opt) {
+ case 'i':
+ nr_tests = atoi(optarg);
+ break;
+ case 'h':
+ default:
+ usage(argv[0]);
+ return 0;
+ }
+ }
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+ return test(filename, nr_tests);
+}