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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andriin@fb.com>
Cc: Wenbo Zhang <ethercflow@gmail.com>,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	Martin KaFai Lau <kafai@fb.com>, David Miller <davem@redhat.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Brendan Gregg <bgregg@netflix.com>,
	Florent Revest <revest@chromium.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH v9 bpf-next 13/14] selftests/bpf: Add test for d_path helper
Date: Sat,  1 Aug 2020 19:03:21 +0200
Message-ID: <20200801170322.75218-14-jolsa@kernel.org> (raw)
In-Reply-To: <20200801170322.75218-1-jolsa@kernel.org>

Adding test for d_path helper which is pretty much
copied from Wenbo Zhang's test for bpf_get_fd_path,
which never made it in.

The test is doing fstat/close on several fd types,
and verifies we got the d_path helper working on
kernel probes for vfs_getattr/filp_close functions.

Original-patch-by: Wenbo Zhang <ethercflow@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 .../testing/selftests/bpf/prog_tests/d_path.c | 147 ++++++++++++++++++
 .../testing/selftests/bpf/progs/test_d_path.c |  64 ++++++++
 2 files changed, 211 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/d_path.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_d_path.c

diff --git a/tools/testing/selftests/bpf/prog_tests/d_path.c b/tools/testing/selftests/bpf/prog_tests/d_path.c
new file mode 100644
index 000000000000..058765da17e6
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/d_path.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <test_progs.h>
+#include <sys/stat.h>
+#include <linux/sched.h>
+#include <sys/syscall.h>
+
+#define MAX_PATH_LEN		128
+#define MAX_FILES		7
+
+#include "test_d_path.skel.h"
+
+static int duration;
+
+static struct {
+	__u32 cnt;
+	char paths[MAX_FILES][MAX_PATH_LEN];
+} src;
+
+static int set_pathname(int fd, pid_t pid)
+{
+	char buf[MAX_PATH_LEN];
+
+	snprintf(buf, MAX_PATH_LEN, "/proc/%d/fd/%d", pid, fd);
+	return readlink(buf, src.paths[src.cnt++], MAX_PATH_LEN);
+}
+
+static int trigger_fstat_events(pid_t pid)
+{
+	int sockfd = -1, procfd = -1, devfd = -1;
+	int localfd = -1, indicatorfd = -1;
+	int pipefd[2] = { -1, -1 };
+	struct stat fileStat;
+	int ret = -1;
+
+	/* unmountable pseudo-filesystems */
+	if (CHECK(pipe(pipefd) < 0, "trigger", "pipe failed\n"))
+		return ret;
+	/* unmountable pseudo-filesystems */
+	sockfd = socket(AF_INET, SOCK_STREAM, 0);
+	if (CHECK(sockfd < 0, "trigger", "scoket failed\n"))
+		goto out_close;
+	/* mountable pseudo-filesystems */
+	procfd = open("/proc/self/comm", O_RDONLY);
+	if (CHECK(procfd < 0, "trigger", "open /proc/self/comm failed\n"))
+		goto out_close;
+	devfd = open("/dev/urandom", O_RDONLY);
+	if (CHECK(devfd < 0, "trigger", "open /dev/urandom failed\n"))
+		goto out_close;
+	localfd = open("/tmp/d_path_loadgen.txt", O_CREAT | O_RDONLY);
+	if (CHECK(localfd < 0, "trigger", "open /tmp/d_path_loadgen.txt failed\n"))
+		goto out_close;
+	/* bpf_d_path will return path with (deleted) */
+	remove("/tmp/d_path_loadgen.txt");
+	indicatorfd = open("/tmp/", O_PATH);
+	if (CHECK(indicatorfd < 0, "trigger", "open /tmp/ failed\n"))
+		goto out_close;
+
+	ret = set_pathname(pipefd[0], pid);
+	if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[0]\n"))
+		goto out_close;
+	ret = set_pathname(pipefd[1], pid);
+	if (CHECK(ret < 0, "trigger", "set_pathname failed for pipe[1]\n"))
+		goto out_close;
+	ret = set_pathname(sockfd, pid);
+	if (CHECK(ret < 0, "trigger", "set_pathname failed for socket\n"))
+		goto out_close;
+	ret = set_pathname(procfd, pid);
+	if (CHECK(ret < 0, "trigger", "set_pathname failed for proc\n"))
+		goto out_close;
+	ret = set_pathname(devfd, pid);
+	if (CHECK(ret < 0, "trigger", "set_pathname failed for dev\n"))
+		goto out_close;
+	ret = set_pathname(localfd, pid);
+	if (CHECK(ret < 0, "trigger", "set_pathname failed for file\n"))
+		goto out_close;
+	ret = set_pathname(indicatorfd, pid);
+	if (CHECK(ret < 0, "trigger", "set_pathname failed for dir\n"))
+		goto out_close;
+
+	/* triggers vfs_getattr */
+	fstat(pipefd[0], &fileStat);
+	fstat(pipefd[1], &fileStat);
+	fstat(sockfd, &fileStat);
+	fstat(procfd, &fileStat);
+	fstat(devfd, &fileStat);
+	fstat(localfd, &fileStat);
+	fstat(indicatorfd, &fileStat);
+
+out_close:
+	/* triggers filp_close */
+	close(pipefd[0]);
+	close(pipefd[1]);
+	close(sockfd);
+	close(procfd);
+	close(devfd);
+	close(localfd);
+	close(indicatorfd);
+	return ret;
+}
+
+void test_d_path(void)
+{
+	struct test_d_path__bss *bss;
+	struct test_d_path *skel;
+	int err;
+
+	skel = test_d_path__open_and_load();
+	if (CHECK(!skel, "setup", "d_path skeleton failed\n"))
+		goto cleanup;
+
+	err = test_d_path__attach(skel);
+	if (CHECK(err, "setup", "attach failed: %d\n", err))
+		goto cleanup;
+
+	bss = skel->bss;
+	bss->my_pid = getpid();
+
+	err = trigger_fstat_events(bss->my_pid);
+	if (err < 0)
+		goto cleanup;
+
+	for (int i = 0; i < MAX_FILES; i++) {
+		CHECK(strncmp(src.paths[i], bss->paths_stat[i], MAX_PATH_LEN),
+		      "check",
+		      "failed to get stat path[%d]: %s vs %s\n",
+		      i, src.paths[i], bss->paths_stat[i]);
+		CHECK(strncmp(src.paths[i], bss->paths_close[i], MAX_PATH_LEN),
+		      "check",
+		      "failed to get close path[%d]: %s vs %s\n",
+		      i, src.paths[i], bss->paths_close[i]);
+		/* The d_path helper returns size plus NUL char, hence + 1 */
+		CHECK(bss->rets_stat[i] != strlen(bss->paths_stat[i]) + 1,
+		      "check",
+		      "failed to match stat return [%d]: %d vs %zd [%s]\n",
+		      i, bss->rets_stat[i], strlen(bss->paths_stat[i]) + 1,
+		      bss->paths_stat[i]);
+		CHECK(bss->rets_close[i] != strlen(bss->paths_stat[i]) + 1,
+		      "check",
+		      "failed to match stat return [%d]: %d vs %zd [%s]\n",
+		      i, bss->rets_close[i], strlen(bss->paths_close[i]) + 1,
+		      bss->paths_stat[i]);
+	}
+
+cleanup:
+	test_d_path__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_d_path.c b/tools/testing/selftests/bpf/progs/test_d_path.c
new file mode 100644
index 000000000000..9d342d7a1de6
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_d_path.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#define MAX_PATH_LEN		128
+#define MAX_FILES		7
+
+pid_t my_pid = 0;
+__u32 cnt_stat = 0;
+__u32 cnt_close = 0;
+char paths_stat[MAX_FILES][MAX_PATH_LEN] = {};
+char paths_close[MAX_FILES][MAX_PATH_LEN] = {};
+int rets_stat[MAX_FILES] = {};
+int rets_close[MAX_FILES] = {};
+
+SEC("fentry/vfs_getattr")
+int BPF_PROG(prog_stat, struct path *path, struct kstat *stat,
+	     __u32 request_mask, unsigned int query_flags)
+{
+	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+	int ret;
+
+	if (pid != my_pid)
+		return 0;
+
+	if (cnt_stat >= MAX_FILES)
+		return 0;
+	ret = bpf_d_path(path, paths_stat[cnt_stat], MAX_PATH_LEN);
+
+	/* We need to recheck cnt_stat for verifier. */
+	if (cnt_stat >= MAX_FILES)
+		return 0;
+	rets_stat[cnt_stat] = ret;
+
+	cnt_stat++;
+	return 0;
+}
+
+SEC("fentry/filp_close")
+int BPF_PROG(prog_close, struct file *file, void *id)
+{
+	pid_t pid = bpf_get_current_pid_tgid() >> 32;
+	int ret;
+
+	if (pid != my_pid)
+		return 0;
+
+	if (cnt_close >= MAX_FILES)
+		return 0;
+	ret = bpf_d_path(&file->f_path,
+			 paths_close[cnt_close], MAX_PATH_LEN);
+
+	/* We need to recheck cnt_stat for verifier. */
+	if (cnt_close >= MAX_FILES)
+		return 0;
+	rets_close[cnt_close] = ret;
+
+	cnt_close++;
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.25.4


  parent reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-01 17:03 [PATCH v9 bpf-next 00/14] bpf: Add " Jiri Olsa
2020-08-01 17:03 ` [PATCH v9 bpf-next 01/14] tools resolve_btfids: Add size check to get_id function Jiri Olsa
2020-08-05  6:00   ` Andrii Nakryiko
2020-08-01 17:03 ` [PATCH v9 bpf-next 02/14] tools resolve_btfids: Add support for set symbols Jiri Olsa
2020-08-05  6:04   ` Andrii Nakryiko
2020-08-01 17:03 ` [PATCH v9 bpf-next 03/14] bpf: Move btf_resolve_size into __btf_resolve_size Jiri Olsa
2020-08-01 17:03 ` [PATCH v9 bpf-next 04/14] bpf: Add elem_id pointer as argument to __btf_resolve_size Jiri Olsa
2020-08-01 17:03 ` [PATCH v9 bpf-next 05/14] bpf: Add type_id " Jiri Olsa
2020-08-05  6:05   ` Andrii Nakryiko
2020-08-01 17:03 ` [PATCH v9 bpf-next 06/14] bpf: Remove recursion call in btf_struct_access Jiri Olsa
2020-08-05  6:12   ` Andrii Nakryiko
2020-08-05 17:36     ` Jiri Olsa
2020-08-01 17:03 ` [PATCH v9 bpf-next 07/14] bpf: Factor btf_struct_access function Jiri Olsa
2020-08-05  6:18   ` Andrii Nakryiko
2020-08-01 17:03 ` [PATCH v9 bpf-next 08/14] bpf: Add btf_struct_ids_match function Jiri Olsa
2020-08-05  6:27   ` Andrii Nakryiko
2020-08-05 17:56     ` Jiri Olsa
2020-08-05 21:31       ` Jiri Olsa
2020-08-05 21:57         ` Andrii Nakryiko
2020-08-01 17:03 ` [PATCH v9 bpf-next 09/14] bpf: Add BTF_SET_START/END macros Jiri Olsa
2020-08-05  6:29   ` Andrii Nakryiko
2020-08-01 17:03 ` [PATCH v9 bpf-next 10/14] bpf: Add d_path helper Jiri Olsa
2020-08-02  3:13   ` Alexei Starovoitov
2020-08-02 18:26     ` Jiri Olsa
2020-08-05  6:35   ` Andrii Nakryiko
2020-08-05 17:58     ` Jiri Olsa
2020-08-05 21:01       ` Jiri Olsa
2020-08-05 21:09         ` Andrii Nakryiko
2020-08-07  0:31   ` KP Singh
2020-08-07  8:35     ` Jiri Olsa
2020-08-07  9:42       ` KP Singh
2020-08-01 17:03 ` [PATCH v9 bpf-next 11/14] bpf: Update .BTF_ids section in btf.rst with sets info Jiri Olsa
2020-08-01 17:03 ` [PATCH v9 bpf-next 12/14] selftests/bpf: Add verifier test for d_path helper Jiri Olsa
2020-08-01 17:03 ` Jiri Olsa [this message]
2020-08-05  6:40   ` [PATCH v9 bpf-next 13/14] selftests/bpf: Add " Andrii Nakryiko
2020-08-05 18:00     ` Jiri Olsa
2020-08-01 17:03 ` [PATCH v9 bpf-next 14/14] selftests/bpf: Add set test to resolve_btfids Jiri Olsa
2020-08-05  6:41   ` Andrii Nakryiko

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