bpf: add a test case to test single tp multiple bpf attachment

The bpf sample program syscall_tp is modified to
show attachment of more than bpf programs
for a particular kernel tracepoint.

Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/samples/bpf/syscall_tp_user.c b/samples/bpf/syscall_tp_user.c
index a3cb91e..9169d32 100644 (file)
--- a/samples/bpf/syscall_tp_user.c
+++ b/samples/bpf/syscall_tp_user.c
@@ -23,6 +23,13 @@
  * This requires kernel CONFIG_FTRACE_SYSCALLS to be set.
  */
 
+static void usage(const char *cmd)
+{
+       printf("USAGE: %s [-i num_progs] [-h]\n", cmd);
+       printf("       -i num_progs      # number of progs of the test\n");
+       printf("       -h                # help\n");
+}
+
 static void verify_map(int map_id)
 {
        __u32 key = 0;
@@ -32,22 +39,29 @@ static void verify_map(int map_id)
                fprintf(stderr, "map_lookup failed: %s\n", strerror(errno));
                return;
        }
-       if (val == 0)
+       if (val == 0) {
                fprintf(stderr, "failed: map #%d returns value 0\n", map_id);
+               return;
+       }
+       val = 0;
+       if (bpf_map_update_elem(map_id, &key, &val, BPF_ANY) != 0) {
+               fprintf(stderr, "map_update failed: %s\n", strerror(errno));
+               return;
+       }
 }
 
-int main(int argc, char **argv)
+static int test(char *filename, int num_progs)
 {
-       struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
-       char filename[256];
-       int fd;
+       int i, fd, map0_fds[num_progs], map1_fds[num_progs];
 
-       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;
+       for (i = 0; i < num_progs; i++) {
+               if (load_bpf_file(filename)) {
+                       fprintf(stderr, "%s", bpf_log_buf);
+                       return 1;
+               }
+               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];
        }
 
        /* current load_bpf_file has perf_event_open default pid = -1
@@ -64,8 +78,34 @@ int main(int argc, char **argv)
        close(fd);
 
        /* verify the map */
-       verify_map(map_fd[0]);
-       verify_map(map_fd[1]);
+       for (i = 0; i < num_progs; i++) {
+               verify_map(map0_fds[i]);
+               verify_map(map1_fds[i]);
+       }
 
        return 0;
 }
+
+int main(int argc, char **argv)
+{
+       struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
+       int opt, num_progs = 1;
+       char filename[256];
+
+       while ((opt = getopt(argc, argv, "i:h")) != -1) {
+               switch (opt) {
+               case 'i':
+                       num_progs = atoi(optarg);
+                       break;
+               case 'h':
+               default:
+                       usage(argv[0]);
+                       return 0;
+               }
+       }
+
+       setrlimit(RLIMIT_MEMLOCK, &r);
+       snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+       return test(filename, num_progs);
+}