1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (c) 2018 Facebook 3 4 #include <stdio.h> 5 #include <stdlib.h> 6 #include <string.h> 7 #include <errno.h> 8 #include <fcntl.h> 9 #include <syscall.h> 10 #include <unistd.h> 11 #include <linux/perf_event.h> 12 #include <sys/ioctl.h> 13 #include <sys/time.h> 14 #include <sys/types.h> 15 #include <sys/stat.h> 16 17 #include <linux/bpf.h> 18 #include <bpf/bpf.h> 19 #include <bpf/libbpf.h> 20 21 #include "cgroup_helpers.h" 22 #include "testing_helpers.h" 23 24 #define CHECK(condition, tag, format...) ({ \ 25 int __ret = !!(condition); \ 26 if (__ret) { \ 27 printf("%s:FAIL:%s ", __func__, tag); \ 28 printf(format); \ 29 } else { \ 30 printf("%s:PASS:%s\n", __func__, tag); \ 31 } \ 32 __ret; \ 33 }) 34 35 static int bpf_find_map(const char *test, struct bpf_object *obj, 36 const char *name) 37 { 38 struct bpf_map *map; 39 40 map = bpf_object__find_map_by_name(obj, name); 41 if (!map) 42 return -1; 43 return bpf_map__fd(map); 44 } 45 46 #define TEST_CGROUP "/test-bpf-get-cgroup-id/" 47 48 int main(int argc, char **argv) 49 { 50 const char *probe_name = "syscalls/sys_enter_nanosleep"; 51 const char *file = "get_cgroup_id_kern.bpf.o"; 52 int err, bytes, efd, prog_fd, pmu_fd; 53 int cgroup_fd, cgidmap_fd, pidmap_fd; 54 struct perf_event_attr attr = {}; 55 struct bpf_object *obj; 56 __u64 kcgid = 0, ucgid; 57 __u32 key = 0, pid; 58 int exit_code = 1; 59 char buf[256]; 60 const struct timespec req = { 61 .tv_sec = 1, 62 .tv_nsec = 0, 63 }; 64 65 cgroup_fd = cgroup_setup_and_join(TEST_CGROUP); 66 if (CHECK(cgroup_fd < 0, "cgroup_setup_and_join", "err %d errno %d\n", cgroup_fd, errno)) 67 return 1; 68 69 /* Use libbpf 1.0 API mode */ 70 libbpf_set_strict_mode(LIBBPF_STRICT_ALL); 71 72 err = bpf_prog_test_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd); 73 if (CHECK(err, "bpf_prog_test_load", "err %d errno %d\n", err, errno)) 74 goto cleanup_cgroup_env; 75 76 cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids"); 77 if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", 78 cgidmap_fd, errno)) 79 goto close_prog; 80 81 pidmap_fd = bpf_find_map(__func__, obj, "pidmap"); 82 if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", 83 pidmap_fd, errno)) 84 goto close_prog; 85 86 pid = getpid(); 87 bpf_map_update_elem(pidmap_fd, &key, &pid, 0); 88 89 snprintf(buf, sizeof(buf), 90 "/sys/kernel/debug/tracing/events/%s/id", probe_name); 91 efd = open(buf, O_RDONLY, 0); 92 if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) 93 goto close_prog; 94 bytes = read(efd, buf, sizeof(buf)); 95 close(efd); 96 if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read", 97 "bytes %d errno %d\n", bytes, errno)) 98 goto close_prog; 99 100 attr.config = strtol(buf, NULL, 0); 101 attr.type = PERF_TYPE_TRACEPOINT; 102 attr.sample_type = PERF_SAMPLE_RAW; 103 attr.sample_period = 1; 104 attr.wakeup_events = 1; 105 106 /* attach to this pid so the all bpf invocations will be in the 107 * cgroup associated with this pid. 108 */ 109 pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0); 110 if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd, 111 errno)) 112 goto close_prog; 113 114 err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); 115 if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err, 116 errno)) 117 goto close_pmu; 118 119 err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); 120 if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err, 121 errno)) 122 goto close_pmu; 123 124 /* trigger some syscalls */ 125 syscall(__NR_nanosleep, &req, NULL); 126 127 err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid); 128 if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno)) 129 goto close_pmu; 130 131 ucgid = get_cgroup_id(TEST_CGROUP); 132 if (CHECK(kcgid != ucgid, "compare_cgroup_id", 133 "kern cgid %llx user cgid %llx", kcgid, ucgid)) 134 goto close_pmu; 135 136 exit_code = 0; 137 printf("%s:PASS\n", argv[0]); 138 139 close_pmu: 140 close(pmu_fd); 141 close_prog: 142 bpf_object__close(obj); 143 cleanup_cgroup_env: 144 cleanup_cgroup_environment(); 145 return exit_code; 146 } 147