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 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 err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd); 70 if (CHECK(err, "bpf_prog_load", "err %d errno %d\n", err, errno)) 71 goto cleanup_cgroup_env; 72 73 cgidmap_fd = bpf_find_map(__func__, obj, "cg_ids"); 74 if (CHECK(cgidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", 75 cgidmap_fd, errno)) 76 goto close_prog; 77 78 pidmap_fd = bpf_find_map(__func__, obj, "pidmap"); 79 if (CHECK(pidmap_fd < 0, "bpf_find_map", "err %d errno %d\n", 80 pidmap_fd, errno)) 81 goto close_prog; 82 83 pid = getpid(); 84 bpf_map_update_elem(pidmap_fd, &key, &pid, 0); 85 86 snprintf(buf, sizeof(buf), 87 "/sys/kernel/debug/tracing/events/%s/id", probe_name); 88 efd = open(buf, O_RDONLY, 0); 89 if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) 90 goto close_prog; 91 bytes = read(efd, buf, sizeof(buf)); 92 close(efd); 93 if (CHECK(bytes <= 0 || bytes >= sizeof(buf), "read", 94 "bytes %d errno %d\n", bytes, errno)) 95 goto close_prog; 96 97 attr.config = strtol(buf, NULL, 0); 98 attr.type = PERF_TYPE_TRACEPOINT; 99 attr.sample_type = PERF_SAMPLE_RAW; 100 attr.sample_period = 1; 101 attr.wakeup_events = 1; 102 103 /* attach to this pid so the all bpf invocations will be in the 104 * cgroup associated with this pid. 105 */ 106 pmu_fd = syscall(__NR_perf_event_open, &attr, getpid(), -1, -1, 0); 107 if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", pmu_fd, 108 errno)) 109 goto close_prog; 110 111 err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); 112 if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", err, 113 errno)) 114 goto close_pmu; 115 116 err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); 117 if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", err, 118 errno)) 119 goto close_pmu; 120 121 /* trigger some syscalls */ 122 syscall(__NR_nanosleep, &req, NULL); 123 124 err = bpf_map_lookup_elem(cgidmap_fd, &key, &kcgid); 125 if (CHECK(err, "bpf_map_lookup_elem", "err %d errno %d\n", err, errno)) 126 goto close_pmu; 127 128 ucgid = get_cgroup_id(TEST_CGROUP); 129 if (CHECK(kcgid != ucgid, "compare_cgroup_id", 130 "kern cgid %llx user cgid %llx", kcgid, ucgid)) 131 goto close_pmu; 132 133 exit_code = 0; 134 printf("%s:PASS\n", argv[0]); 135 136 close_pmu: 137 close(pmu_fd); 138 close_prog: 139 bpf_object__close(obj); 140 cleanup_cgroup_env: 141 cleanup_cgroup_environment(); 142 return exit_code; 143 } 144