bpf: add a test case for syscalls/sys_{enter|exit}_* tracepoints

[linux-2.6-microblaze.git] / samples / bpf / syscall_tp_user.c

diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c
new file mode 100644 (file)
index 0000000..a3cb91e
--- /dev/null
+++ b/samples/bpf/syscall_tp_user.c
@@ -0,0 +1,71 @@
+/* Copyright (c) 2017 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <stdio.h>
+#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 "libbpf.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.
+ */
+
+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);
+}
+
+int main(int argc, char **argv)
+{
+       struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+       char filename[256];
+       int fd;
+
+       setrlimit(RLIMIT_MEMLOCK, &r);
+       snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+       if (load_bpf_file(filename)) {
+               fprintf(stderr, "%s", bpf_log_buf);
+               return 1;
+       }
+
+       /* 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 */
+       verify_map(map_fd[0]);
+       verify_map(map_fd[1]);
+
+       return 0;
+}