v4.19.13 snapshot.
diff --git a/samples/bpf/load_sock_ops.c b/samples/bpf/load_sock_ops.c
new file mode 100644
index 0000000..8ecb41e
--- /dev/null
+++ b/samples/bpf/load_sock_ops.c
@@ -0,0 +1,97 @@
+/* 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 <stdlib.h>
+#include <string.h>
+#include <linux/bpf.h>
+#include <bpf/bpf.h>
+#include "bpf_load.h"
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/unistd.h>
+
+static void usage(char *pname)
+{
+ printf("USAGE:\n %s [-l] <cg-path> <prog filename>\n", pname);
+ printf("\tLoad and attach a sock_ops program to the specified "
+ "cgroup\n");
+ printf("\tIf \"-l\" is used, the program will continue to run\n");
+ printf("\tprinting the BPF log buffer\n");
+ printf("\tIf the specified filename does not end in \".o\", it\n");
+ printf("\tappends \"_kern.o\" to the name\n");
+ printf("\n");
+ printf(" %s -r <cg-path>\n", pname);
+ printf("\tDetaches the currently attached sock_ops program\n");
+ printf("\tfrom the specified cgroup\n");
+ printf("\n");
+ exit(1);
+}
+
+int main(int argc, char **argv)
+{
+ int logFlag = 0;
+ int error = 0;
+ char *cg_path;
+ char fn[500];
+ char *prog;
+ int cg_fd;
+
+ if (argc < 3)
+ usage(argv[0]);
+
+ if (!strcmp(argv[1], "-r")) {
+ cg_path = argv[2];
+ cg_fd = open(cg_path, O_DIRECTORY, O_RDONLY);
+ error = bpf_prog_detach(cg_fd, BPF_CGROUP_SOCK_OPS);
+ if (error) {
+ printf("ERROR: bpf_prog_detach: %d (%s)\n",
+ error, strerror(errno));
+ return 2;
+ }
+ return 0;
+ } else if (!strcmp(argv[1], "-h")) {
+ usage(argv[0]);
+ } else if (!strcmp(argv[1], "-l")) {
+ logFlag = 1;
+ if (argc < 4)
+ usage(argv[0]);
+ }
+
+ prog = argv[argc - 1];
+ cg_path = argv[argc - 2];
+ if (strlen(prog) > 480) {
+ fprintf(stderr, "ERROR: program name too long (> 480 chars)\n");
+ return 3;
+ }
+ cg_fd = open(cg_path, O_DIRECTORY, O_RDONLY);
+
+ if (!strcmp(prog + strlen(prog)-2, ".o"))
+ strcpy(fn, prog);
+ else
+ sprintf(fn, "%s_kern.o", prog);
+ if (logFlag)
+ printf("loading bpf file:%s\n", fn);
+ if (load_bpf_file(fn)) {
+ printf("ERROR: load_bpf_file failed for: %s\n", fn);
+ printf("%s", bpf_log_buf);
+ return 4;
+ }
+ if (logFlag)
+ printf("TCP BPF Loaded %s\n", fn);
+
+ error = bpf_prog_attach(prog_fd[0], cg_fd, BPF_CGROUP_SOCK_OPS, 0);
+ if (error) {
+ printf("ERROR: bpf_prog_attach: %d (%s)\n",
+ error, strerror(errno));
+ return 5;
+ } else if (logFlag) {
+ read_trace_pipe();
+ }
+
+ return error;
+}