tools/testing/selftests/bpf/prog_tests/ns_current_pid_tgid.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2020 Carlos Neira cneirabustos@gmail.com */
   3 #include <test_progs.h>
   4 #include <sys/stat.h>
   5 #include <sys/types.h>
   6 #include <unistd.h>
   7 #include <sys/syscall.h>
   8
   9 struct bss {
  10         __u64 dev;
  11         __u64 ino;
  12         __u64 pid_tgid;
  13         __u64 user_pid_tgid;
  14 };
  15
  16 void test_ns_current_pid_tgid(void)
  17 {
  18         const char *probe_name = "raw_tracepoint/sys_enter";
  19         const char *file = "test_ns_current_pid_tgid.o";
  20         int err, key = 0, duration = 0;
  21         struct bpf_link *link = NULL;
  22         struct bpf_program *prog;
  23         struct bpf_map *bss_map;
  24         struct bpf_object *obj;
  25         struct bss bss;
  26         struct stat st;
  27         __u64 id;
  28
  29         obj = bpf_object__open_file(file, NULL);
  30         if (CHECK(IS_ERR(obj), "obj_open", "err %ld\n", PTR_ERR(obj)))
  31                 return;
  32
  33         err = bpf_object__load(obj);
  34         if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
  35                 goto cleanup;
  36
  37         bss_map = bpf_object__find_map_by_name(obj, "test_ns_.bss");
  38         if (CHECK(!bss_map, "find_bss_map", "failed\n"))
  39                 goto cleanup;
  40
  41         prog = bpf_object__find_program_by_title(obj, probe_name);
  42         if (CHECK(!prog, "find_prog", "prog '%s' not found\n",
  43                   probe_name))
  44                 goto cleanup;
  45
  46         memset(&bss, 0, sizeof(bss));
  47         pid_t tid = syscall(SYS_gettid);
  48         pid_t pid = getpid();
  49
  50         id = (__u64) tid << 32 | pid;
  51         bss.user_pid_tgid = id;
  52
  53         if (CHECK_FAIL(stat("/proc/self/ns/pid", &st))) {
  54                 perror("Failed to stat /proc/self/ns/pid");
  55                 goto cleanup;
  56         }
  57
  58         bss.dev = st.st_dev;
  59         bss.ino = st.st_ino;
  60
  61         err = bpf_map_update_elem(bpf_map__fd(bss_map), &key, &bss, 0);
  62         if (CHECK(err, "setting_bss", "failed to set bss : %d\n", err))
  63                 goto cleanup;
  64
  65         link = bpf_program__attach_raw_tracepoint(prog, "sys_enter");
  66         if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n",
  67                   PTR_ERR(link))) {
  68                 link = NULL;
  69                 goto cleanup;
  70         }
  71
  72         /* trigger some syscalls */
  73         usleep(1);
  74
  75         err = bpf_map_lookup_elem(bpf_map__fd(bss_map), &key, &bss);
  76         if (CHECK(err, "set_bss", "failed to get bss : %d\n", err))
  77                 goto cleanup;
  78
  79         if (CHECK(id != bss.pid_tgid, "Compare user pid/tgid vs. bpf pid/tgid",
  80                   "User pid/tgid %llu BPF pid/tgid %llu\n", id, bss.pid_tgid))
  81                 goto cleanup;
  82 cleanup:
  83         bpf_link__destroy(link);
  84         bpf_object__close(obj);
  85 }