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