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 "bpf_rlimit.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.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 61 cgroup_fd = cgroup_setup_and_join(TEST_CGROUP); 62 if (CHECK(cgroup_fd < 0, "cgroup_setup_and_join", "err %d errno %d\n", cgroup_fd, errno)) 63 return 1; 64 65 err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd); 66 if (CHECK(err, "bpf_prog_load", "err %d errno %d\n", err, errno)) 67 goto cleanup_cgroup_env; 68 69 cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids"); 70 if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", 71 cgidmap_fd, errno)) 72 goto close_prog; 73 74 pidmap_fd = bpf_find_map(__func__, obj, "pidmap"); 75 if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", 76 pidmap_fd, errno)) 77 goto close_prog; 78 79 pid = getpid(); 80 bpf_map_update_elem(pidmap_fd, &key, &pid, 0); 81 82 snprintf(buf, sizeof(buf), 83 "/sys/kernel/debug/tracing/events/%s/id", probe_name); 84 efd = open(buf, O_RDONLY, 0); 85 if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) 86 goto close_prog; 87 bytes = read(efd, buf, sizeof(buf)); 88 close(efd); 89 if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read", 90 "bytes %d errno %d\n", bytes, errno)) 91 goto close_prog; 92 93 attr.config = strtol(buf, NULL, 0); 94 attr.type = PERF_TYPE_TRACEPOINT; 95 attr.sample_type = PERF_SAMPLE_RAW; 96 attr.sample_period = 1; 97 attr.wakeup_events = 1; 98 99 /* attach to this pid so the all bpf invocations will be in the 100 * cgroup associated with this pid. 101 */ 102 pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0); 103 if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd, 104 errno)) 105 goto close_prog; 106 107 err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); 108 if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err, 109 errno)) 110 goto close_pmu; 111 112 err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); 113 if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err, 114 errno)) 115 goto close_pmu; 116 117 /* trigger some syscalls */ 118 sleep(1); 119 120 err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid); 121 if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno)) 122 goto close_pmu; 123 124 ucgid = get_cgroup_id(TEST_CGROUP); 125 if (CHECK(kcgid != ucgid, "compare_cgroup_id", 126 "kern cgid %llx user cgid %llx", kcgid, ucgid)) 127 goto close_pmu; 128 129 exit_code = 0; 130 printf("%s:PASS\n", argv[0]); 131 132 close_pmu: 133 close(pmu_fd); 134 close_prog: 135 bpf_object__close(obj); 136 cleanup_cgroup_env: 137 cleanup_cgroup_environment(); 138 return exit_code; 139 } 140