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
bpf_find_map(const char * test,struct bpf_object * obj,const char * name)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
main(int argc,char ** argv)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