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Date: Wed, 9 Oct 2019 09:26:32 -0700
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Carlos Neira <cneirabustos@...il.com>
Cc: Networking <netdev@...r.kernel.org>, Yonghong Song <yhs@...com>,
ebiederm@...ssion.com, Jesper Dangaard Brouer <brouer@...hat.com>,
bpf <bpf@...r.kernel.org>
Subject: Re: [PATCH v13 4/4] tools/testing/selftests/bpf: Add self-tests for
new helper.
On Wed, Oct 9, 2019 at 8:29 AM Carlos Neira <cneirabustos@...il.com> wrote:
>
> Self tests added for new helper
>
> Signed-off-by: Carlos Neira <cneirabustos@...il.com>
> ---
> tools/testing/selftests/bpf/bpf_helpers.h | 4 +
> .../bpf/prog_tests/get_ns_current_pid_tgid.c | 85 +++++++++++++++++++
> .../bpf/progs/get_ns_current_pid_tgid_kern.c | 53 ++++++++++++
> 3 files changed, 142 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/get_ns_current_pid_tgid.c
> create mode 100644 tools/testing/selftests/bpf/progs/get_ns_current_pid_tgid_kern.c
>
> diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
> index 54a50699bbfd..16261b23e011 100644
> --- a/tools/testing/selftests/bpf/bpf_helpers.h
> +++ b/tools/testing/selftests/bpf/bpf_helpers.h
> @@ -233,6 +233,10 @@ static int (*bpf_send_signal)(unsigned sig) = (void *)BPF_FUNC_send_signal;
> static long long (*bpf_tcp_gen_syncookie)(struct bpf_sock *sk, void *ip,
> int ip_len, void *tcp, int tcp_len) =
> (void *) BPF_FUNC_tcp_gen_syncookie;
> +static unsigned long long (*bpf_get_ns_current_pid_tgid)(struct bpf_pidns_info *nsinfo,
> + unsigned int buf_size) =
> + (void *) BPF_FUNC_get_ns_current_pid_tgid;
> +
This is obsolete as of two days ago :) We now generate this
automatically from the bpf.h's documentation (which is currently
broken for your helper, I replied on respective patch). So please pull
latest bpf-next and rebase.
>
> /* llvm builtin functions that eBPF C program may use to
> * emit BPF_LD_ABS and BPF_LD_IND instructions
> diff --git a/tools/testing/selftests/bpf/prog_tests/get_ns_current_pid_tgid.c b/tools/testing/selftests/bpf/prog_tests/get_ns_current_pid_tgid.c
> new file mode 100644
> index 000000000000..a7bff0ef6677
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/get_ns_current_pid_tgid.c
> @@ -0,0 +1,85 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2019 Carlos Neira cneirabustos@...il.com */
> +#include <test_progs.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <unistd.h>
> +#include <sys/syscall.h>
> +
> +void test_get_ns_current_pid_tgid(void)
> +{
> + const char *probe_name = "syscalls/sys_enter_nanosleep";
> + const char *file = "get_ns_current_pid_tgid_kern.o";
> + int ns_data_map_fd, duration = 0;
> + struct perf_event_attr attr = {};
> + int err, efd, prog_fd, pmu_fd;
> + __u64 ino, dev, id, nspid;
> + struct bpf_object *obj;
> + struct stat st;
> + __u32 key = 0;
> + char buf[256];
> +
> + err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
> + if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno))
> + return;
> +
> + ns_data_map_fd = bpf_find_map(__func__, obj, "ns_data_map");
> + if (CHECK_FAIL(ns_data_map_fd < 0))
> + goto close_prog;
> +
> + pid_t tid = syscall(SYS_gettid);
> + pid_t pid = getpid();
> +
> + id = (__u64) tid << 32 | pid;
> + bpf_map_update_elem(ns_data_map_fd, &key, &id, 0);
> +
> + if (stat("/proc/self/ns/pid", &st))
CHECK() or CHECK_FAIL() ?
> + goto close_prog;
> +
> + dev = st.st_dev;
> + ino = st.st_ino;
> + key = 1;
> + bpf_map_update_elem(ns_data_map_fd, &key, &dev, 0);
> + key = 2;
> + bpf_map_update_elem(ns_data_map_fd, &key, &ino, 0);
> +
> + snprintf(buf, sizeof(buf),
> + "/sys/kernel/debug/tracing/events/%s/id", probe_name);
> + efd = open(buf, O_RDONLY, 0);
> + read(efd, buf, sizeof(buf));
> + close(efd);
> + attr.config = strtol(buf, NULL, 0);
> + attr.type = PERF_TYPE_TRACEPOINT;
> + attr.sample_type = PERF_SAMPLE_RAW;
> + attr.sample_period = 1;
> + attr.wakeup_events = 1;
> +
> + pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0);
> + if (CHECK_FAIL(pmu_fd < 0))
> + goto cleanup;
> +
> + err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0);
> + if (CHECK_FAIL(err))
> + goto cleanup;
> +
> + err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);
> + if (CHECK_FAIL(err))
> + goto cleanup;
All this attaching boilerplate is now obsolete as well, stick to
bpf_program__attach_tracepoint(). But even better, use RAW_TRACEPOINT.
> +
> + /* trigger some syscalls */
> + sleep(1);
> + key = 3;
> + err = bpf_map_lookup_elem(ns_data_map_fd, &key, &nspid);
> + if (CHECK_FAIL(err))
> + goto cleanup;
> +
> + if (CHECK(id != nspid, "Compare user pid/tgid vs. bpf pid/tgid",
> + "Userspace pid/tgid %llu EBPF pid/tgid %llu\n", id, nspid))
> + goto cleanup;
> +
> +cleanup:
> + close(pmu_fd);
> +close_prog:
> + bpf_object__close(obj);
> +}
> diff --git a/tools/testing/selftests/bpf/progs/get_ns_current_pid_tgid_kern.c b/tools/testing/selftests/bpf/progs/get_ns_current_pid_tgid_kern.c
> new file mode 100644
> index 000000000000..3659aaa7c71f
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/get_ns_current_pid_tgid_kern.c
> @@ -0,0 +1,53 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2019 Carlos Neira cneirabustos@...il.com */
> +
> +#include <linux/bpf.h>
> +#include "bpf_helpers.h"
> +
> +struct {
> + __uint(type, BPF_MAP_TYPE_ARRAY);
> + __uint(max_entries, 4);
> + __type(key, __u32);
> + __type(value, __u64);
> +} ns_data_map SEC(".maps");
> +
> +
> +SEC("tracepoint/syscalls/sys_enter_nanosleep")
> +int trace(void *ctx)
> +{
> + __u64 *val, *inum, *dev, nspidtgid, *expected_pid;
> + struct bpf_pidns_info nsdata;
> + __u32 key = 1;
> +
> + dev = bpf_map_lookup_elem(&ns_data_map, &key);
> + if (!dev)
> + return 0;
> + key = 2;
> + inum = bpf_map_lookup_elem(&ns_data_map, &key);
> + if (!inum)
> + return 0;
> +
> + nsdata.dev = *dev;
> + nsdata.inum = *inum;
> +
> + if (bpf_get_ns_current_pid_tgid(&nsdata, sizeof(struct bpf_pidns_info)))
> + return 0;
> +
> + nspidtgid = (__u64)nsdata.tgid << 32 | nsdata.pid;
> + key = 0;
> + expected_pid = bpf_map_lookup_elem(&ns_data_map, &key);
> +
> + if (!expected_pid || *expected_pid != nspidtgid)
> + return 0;
> +
> + key = 3;
> + val = bpf_map_lookup_elem(&ns_data_map, &key);
Please, use global data for this, will make this BPF program much
shorter, cleaner, and up to the point. See recent patch by Daniel T.
Lee, or some of the tests I added (e.g.,
progs/test_core_reloc_kernel.c)
> +
> + if (val)
> + *val = nspidtgid;
> +
> + return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> +__u32 _version SEC("version") = 1;
You can drop version now (recent stuff), it's not required by libbpf anymore.
> --
> 2.20.1
>
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