selftests/bpf: convert test_cgrp2_attach2 example into kselftest

Convert test_cgrp2_attach2 example into a proper test_cgroup_attach
kselftest. It's better because we do run kselftest on a constant
basis, so there are better chances to spot a potential regression.

Also make it slightly less verbose to conform kselftests output style.

Output example:
  $ ./test_cgroup_attach
  #override:PASS
  #multi:PASS
  test_cgroup_attach:PASS

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

samples/bpf/Makefile

@@ -26,7 +26,6 @@ hostprogs-y += map_perf_test
 hostprogs-y += test_overhead
 hostprogs-y += test_cgrp2_array_pin
 hostprogs-y += test_cgrp2_attach
-hostprogs-y += test_cgrp2_attach2
 hostprogs-y += test_cgrp2_sock
 hostprogs-y += test_cgrp2_sock2
 hostprogs-y += xdp1
@@ -81,7 +80,6 @@ map_perf_test-objs := bpf_load.o map_perf_test_user.o
 test_overhead-objs := bpf_load.o test_overhead_user.o
 test_cgrp2_array_pin-objs := test_cgrp2_array_pin.o
 test_cgrp2_attach-objs := test_cgrp2_attach.o
-test_cgrp2_attach2-objs := test_cgrp2_attach2.o $(CGROUP_HELPERS)
 test_cgrp2_sock-objs := test_cgrp2_sock.o
 test_cgrp2_sock2-objs := bpf_load.o test_cgrp2_sock2.o
 xdp1-objs := xdp1_user.o

tools/testing/selftests/bpf/.gitignore

@@ -22,6 +22,7 @@ test_lirc_mode2_user
 get_cgroup_id_user
 test_skb_cgroup_id_user
 test_socket_cookie
+test_cgroup_attach
 test_cgroup_storage
 test_select_reuseport
 test_flow_dissector

tools/testing/selftests/bpf/Makefile

@@ -26,7 +26,7 @@ TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test
 	test_sock test_btf test_sockmap test_lirc_mode2_user get_cgroup_id_user \
 	test_socket_cookie test_cgroup_storage test_select_reuseport test_section_names \
 	test_netcnt test_tcpnotify_user test_sock_fields test_sysctl test_hashmap \
-	test_btf_dump
+	test_btf_dump test_cgroup_attach
 
 BPF_OBJ_FILES = $(patsubst %.c,%.o, $(notdir $(wildcard progs/*.c)))
 TEST_GEN_FILES = $(BPF_OBJ_FILES)
@@ -99,6 +99,7 @@ $(OUTPUT)/test_cgroup_storage: cgroup_helpers.c
 $(OUTPUT)/test_netcnt: cgroup_helpers.c
 $(OUTPUT)/test_sock_fields: cgroup_helpers.c
 $(OUTPUT)/test_sysctl: cgroup_helpers.c
+$(OUTPUT)/test_cgroup_attach: cgroup_helpers.c
 
 .PHONY: force
 

tools/testing/selftests/bpf/test_cgroup_attach.c

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+
 /* eBPF example program:
  *
  * - Creates arraymap in kernel with 4 bytes keys and 8 byte values
@@ -25,20 +27,27 @@
 #include <sys/resource.h>
 #include <sys/time.h>
 #include <unistd.h>
+#include <linux/filter.h>
 
 #include <linux/bpf.h>
 #include <bpf/bpf.h>
 
-#include "bpf_insn.h"
+#include "bpf_util.h"
 #include "bpf_rlimit.h"
 #include "cgroup_helpers.h"
 
 #define FOO		"/foo"
 #define BAR		"/foo/bar/"
-#define PING_CMD	"ping -c1 -w1 127.0.0.1 > /dev/null"
+#define PING_CMD	"ping -q -c1 -w1 127.0.0.1 > /dev/null"
 
 char bpf_log_buf[BPF_LOG_BUF_SIZE];
 
+#ifdef DEBUG
+#define debug(args...) printf(args)
+#else
+#define debug(args...)
+#endif
+
 static int prog_load(int verdict)
 {
 	int ret;
@@ -89,7 +98,7 @@ static int test_foo_bar(void)
 		goto err;
 	}
 
-	printf("Attached DROP prog. This ping in cgroup /foo should fail...\n");
+	debug("Attached DROP prog. This ping in cgroup /foo should fail...\n");
 	assert(system(PING_CMD) != 0);
 
 	/* Create cgroup /foo/bar, get fd, and join it */
@@ -100,7 +109,7 @@ static int test_foo_bar(void)
 	if (join_cgroup(BAR))
 		goto err;
 
-	printf("Attached DROP prog. This ping in cgroup /foo/bar should fail...\n");
+	debug("Attached DROP prog. This ping in cgroup /foo/bar should fail...\n");
 	assert(system(PING_CMD) != 0);
 
 	if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS,
@@ -109,7 +118,7 @@ static int test_foo_bar(void)
 		goto err;
 	}
 
-	printf("Attached PASS prog. This ping in cgroup /foo/bar should pass...\n");
+	debug("Attached PASS prog. This ping in cgroup /foo/bar should pass...\n");
 	assert(system(PING_CMD) == 0);
 
 	if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
@@ -117,7 +126,7 @@ static int test_foo_bar(void)
 		goto err;
 	}
 
-	printf("Detached PASS from /foo/bar while DROP is attached to /foo.\n"
+	debug("Detached PASS from /foo/bar while DROP is attached to /foo.\n"
 	       "This ping in cgroup /foo/bar should fail...\n");
 	assert(system(PING_CMD) != 0);
 
@@ -132,7 +141,7 @@ static int test_foo_bar(void)
 		goto err;
 	}
 
-	printf("Attached PASS from /foo/bar and detached DROP from /foo.\n"
+	debug("Attached PASS from /foo/bar and detached DROP from /foo.\n"
 	       "This ping in cgroup /foo/bar should pass...\n");
 	assert(system(PING_CMD) == 0);
 
@@ -199,9 +208,9 @@ out:
 	close(bar);
 	cleanup_cgroup_environment();
 	if (!rc)
-		printf("### override:PASS\n");
+		printf("#override:PASS\n");
 	else
-		printf("### override:FAIL\n");
+		printf("#override:FAIL\n");
 	return rc;
 }
 
@@ -441,19 +450,26 @@ out:
 	close(cg5);
 	cleanup_cgroup_environment();
 	if (!rc)
-		printf("### multi:PASS\n");
+		printf("#multi:PASS\n");
 	else
-		printf("### multi:FAIL\n");
+		printf("#multi:FAIL\n");
 	return rc;
 }
 
-int main(int argc, char **argv)
+int main(void)
 {
-	int rc = 0;
+	int (*tests[])(void) = {test_foo_bar, test_multiprog};
+	int errors = 0;
+	int i;
 
-	rc = test_foo_bar();
-	if (rc)
-		return rc;
+	for (i = 0; i < ARRAY_SIZE(tests); i++)
+		if (tests[i]())
+			errors++;
 
-	return test_multiprog();
+	if (errors)
+		printf("test_cgroup_attach:FAIL\n");
+	else
+		printf("test_cgroup_attach:PASS\n");
+
+	return errors ? EXIT_FAILURE : EXIT_SUCCESS;
 }