]> git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.git/commitdiff
selftests/bpf: Add test for d_path helper
authorJiri Olsa <jolsa@kernel.org>
Tue, 25 Aug 2020 19:21:23 +0000 (21:21 +0200)
committerAlexei Starovoitov <ast@kernel.org>
Tue, 25 Aug 2020 22:41:15 +0000 (15:41 -0700)
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>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-14-jolsa@kernel.org
tools/testing/selftests/bpf/prog_tests/d_path.c [new file with mode: 0644]
tools/testing/selftests/bpf/progs/test_d_path.c [new file with mode: 0644]

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 (file)
index 0000000..058765d
--- /dev/null
@@ -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 (file)
index 0000000..61f0078
--- /dev/null
@@ -0,0 +1,58 @@
+// 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;
+       __u32 cnt = cnt_stat;
+       int ret;
+
+       if (pid != my_pid)
+               return 0;
+
+       if (cnt >= MAX_FILES)
+               return 0;
+       ret = bpf_d_path(path, paths_stat[cnt], MAX_PATH_LEN);
+
+       rets_stat[cnt] = 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;
+       __u32 cnt = cnt_close;
+       int ret;
+
+       if (pid != my_pid)
+               return 0;
+
+       if (cnt >= MAX_FILES)
+               return 0;
+       ret = bpf_d_path(&file->f_path,
+                        paths_close[cnt], MAX_PATH_LEN);
+
+       rets_close[cnt] = ret;
+       cnt_close++;
+       return 0;
+}
+
+char _license[] SEC("license") = "GPL";