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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/xattr.h>
#include <test_progs.h>
#include "read_cgroupfs_xattr.skel.h"
#include "cgroup_read_xattr.skel.h"
#define CGROUP_FS_ROOT "/sys/fs/cgroup/"
#define CGROUP_FS_PARENT CGROUP_FS_ROOT "foo/"
#define CGROUP_FS_CHILD CGROUP_FS_PARENT "bar/"
static int move_pid_to_cgroup(const char *cgroup_folder, pid_t pid)
{
char filename[128];
char pid_str[64];
int procs_fd;
int ret;
snprintf(filename, sizeof(filename), "%scgroup.procs", cgroup_folder);
snprintf(pid_str, sizeof(pid_str), "%d", pid);
procs_fd = open(filename, O_WRONLY | O_APPEND);
if (!ASSERT_OK_FD(procs_fd, "open"))
return -1;
ret = write(procs_fd, pid_str, strlen(pid_str));
close(procs_fd);
if (!ASSERT_GT(ret, 0, "write cgroup.procs"))
return -1;
return 0;
}
static void reset_cgroups_and_lo(void)
{
rmdir(CGROUP_FS_CHILD);
rmdir(CGROUP_FS_PARENT);
system("ip addr del 1.1.1.1/32 dev lo");
system("ip link set dev lo down");
}
static const char xattr_value_a[] = "bpf_selftest_value_a";
static const char xattr_value_b[] = "bpf_selftest_value_b";
static const char xattr_name[] = "user.bpf_test";
static int setup_cgroups_and_lo(void)
{
int err;
err = mkdir(CGROUP_FS_PARENT, 0755);
if (!ASSERT_OK(err, "mkdir 1"))
goto error;
err = mkdir(CGROUP_FS_CHILD, 0755);
if (!ASSERT_OK(err, "mkdir 2"))
goto error;
err = setxattr(CGROUP_FS_PARENT, xattr_name, xattr_value_a,
strlen(xattr_value_a) + 1, 0);
if (!ASSERT_OK(err, "setxattr 1"))
goto error;
err = setxattr(CGROUP_FS_CHILD, xattr_name, xattr_value_b,
strlen(xattr_value_b) + 1, 0);
if (!ASSERT_OK(err, "setxattr 2"))
goto error;
err = system("ip link set dev lo up");
if (!ASSERT_OK(err, "lo up"))
goto error;
err = system("ip addr add 1.1.1.1 dev lo");
if (!ASSERT_OK(err, "lo addr v4"))
goto error;
err = write_sysctl("/proc/sys/net/ipv4/ping_group_range", "0 0");
if (!ASSERT_OK(err, "write_sysctl"))
goto error;
return 0;
error:
reset_cgroups_and_lo();
return err;
}
static void test_read_cgroup_xattr(void)
{
struct sockaddr_in sa4 = {
.sin_family = AF_INET,
.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
};
struct read_cgroupfs_xattr *skel = NULL;
pid_t pid = gettid();
int sock_fd = -1;
int connect_fd = -1;
if (!ASSERT_OK(setup_cgroups_and_lo(), "setup_cgroups_and_lo"))
return;
if (!ASSERT_OK(move_pid_to_cgroup(CGROUP_FS_CHILD, pid),
"move_pid_to_cgroup"))
goto out;
skel = read_cgroupfs_xattr__open_and_load();
if (!ASSERT_OK_PTR(skel, "read_cgroupfs_xattr__open_and_load"))
goto out;
skel->bss->target_pid = pid;
if (!ASSERT_OK(read_cgroupfs_xattr__attach(skel), "read_cgroupfs_xattr__attach"))
goto out;
sock_fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
if (!ASSERT_OK_FD(sock_fd, "sock create"))
goto out;
connect_fd = connect(sock_fd, &sa4, sizeof(sa4));
if (!ASSERT_OK_FD(connect_fd, "connect 1"))
goto out;
close(connect_fd);
ASSERT_TRUE(skel->bss->found_value_a, "found_value_a");
ASSERT_TRUE(skel->bss->found_value_b, "found_value_b");
out:
close(connect_fd);
close(sock_fd);
read_cgroupfs_xattr__destroy(skel);
move_pid_to_cgroup(CGROUP_FS_ROOT, pid);
reset_cgroups_and_lo();
}
void test_cgroup_xattr(void)
{
RUN_TESTS(cgroup_read_xattr);
if (test__start_subtest("read_cgroupfs_xattr"))
test_read_cgroup_xattr();
}
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