1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2 /* Copyright (c) 2019 Netronome Systems, Inc. */
10 #include <sys/utsname.h>
12 #include <linux/btf.h>
13 #include <linux/filter.h>
14 #include <linux/kernel.h>
15 #include <linux/version.h>
19 #include "libbpf_internal.h"
21 /* On Ubuntu LINUX_VERSION_CODE doesn't correspond to info.release,
22 * but Ubuntu provides /proc/version_signature file, as described at
23 * https://ubuntu.com/kernel, with an example contents below, which we
24 * can use to get a proper LINUX_VERSION_CODE.
26 * Ubuntu 5.4.0-12.15-generic 5.4.8
28 * In the above, 5.4.8 is what kernel is actually expecting, while
29 * uname() call will return 5.4.0 in info.release.
31 static __u32 get_ubuntu_kernel_version(void)
33 const char *ubuntu_kver_file = "/proc/version_signature";
34 __u32 major, minor, patch;
38 if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) != 0)
41 f = fopen(ubuntu_kver_file, "re");
45 ret = fscanf(f, "%*s %*s %u.%u.%u\n", &major, &minor, &patch);
50 return KERNEL_VERSION(major, minor, patch);
53 /* On Debian LINUX_VERSION_CODE doesn't correspond to info.release.
54 * Instead, it is provided in info.version. An example content of
55 * Debian 10 looks like the below.
57 * utsname::release 4.19.0-22-amd64
58 * utsname::version #1 SMP Debian 4.19.260-1 (2022-09-29)
60 * In the above, 4.19.260 is what kernel is actually expecting, while
61 * uname() call will return 4.19.0 in info.release.
63 static __u32 get_debian_kernel_version(struct utsname *info)
65 __u32 major, minor, patch;
68 p = strstr(info->version, "Debian ");
70 /* This is not a Debian kernel. */
74 if (sscanf(p, "Debian %u.%u.%u", &major, &minor, &patch) != 3)
77 return KERNEL_VERSION(major, minor, patch);
80 __u32 get_kernel_version(void)
82 __u32 major, minor, patch, version;
85 /* Check if this is an Ubuntu kernel. */
86 version = get_ubuntu_kernel_version();
92 /* Check if this is a Debian kernel. */
93 version = get_debian_kernel_version(&info);
97 if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
100 return KERNEL_VERSION(major, minor, patch);
103 static int probe_prog_load(enum bpf_prog_type prog_type,
104 const struct bpf_insn *insns, size_t insns_cnt,
105 char *log_buf, size_t log_buf_sz)
107 LIBBPF_OPTS(bpf_prog_load_opts, opts,
109 .log_size = log_buf_sz,
110 .log_level = log_buf ? 1 : 0,
112 int fd, err, exp_err = 0;
113 const char *exp_msg = NULL;
117 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
118 opts.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
120 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
121 opts.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
123 case BPF_PROG_TYPE_SK_LOOKUP:
124 opts.expected_attach_type = BPF_SK_LOOKUP;
126 case BPF_PROG_TYPE_KPROBE:
127 opts.kern_version = get_kernel_version();
129 case BPF_PROG_TYPE_LIRC_MODE2:
130 opts.expected_attach_type = BPF_LIRC_MODE2;
132 case BPF_PROG_TYPE_TRACING:
133 case BPF_PROG_TYPE_LSM:
135 opts.log_size = sizeof(buf);
137 if (prog_type == BPF_PROG_TYPE_TRACING)
138 opts.expected_attach_type = BPF_TRACE_FENTRY;
140 opts.expected_attach_type = BPF_MODIFY_RETURN;
141 opts.attach_btf_id = 1;
144 exp_msg = "attach_btf_id 1 is not a function";
146 case BPF_PROG_TYPE_EXT:
148 opts.log_size = sizeof(buf);
150 opts.attach_btf_id = 1;
153 exp_msg = "Cannot replace kernel functions";
155 case BPF_PROG_TYPE_SYSCALL:
156 opts.prog_flags = BPF_F_SLEEPABLE;
158 case BPF_PROG_TYPE_STRUCT_OPS:
159 exp_err = -524; /* -ENOTSUPP */
161 case BPF_PROG_TYPE_UNSPEC:
162 case BPF_PROG_TYPE_SOCKET_FILTER:
163 case BPF_PROG_TYPE_SCHED_CLS:
164 case BPF_PROG_TYPE_SCHED_ACT:
165 case BPF_PROG_TYPE_TRACEPOINT:
166 case BPF_PROG_TYPE_XDP:
167 case BPF_PROG_TYPE_PERF_EVENT:
168 case BPF_PROG_TYPE_CGROUP_SKB:
169 case BPF_PROG_TYPE_CGROUP_SOCK:
170 case BPF_PROG_TYPE_LWT_IN:
171 case BPF_PROG_TYPE_LWT_OUT:
172 case BPF_PROG_TYPE_LWT_XMIT:
173 case BPF_PROG_TYPE_SOCK_OPS:
174 case BPF_PROG_TYPE_SK_SKB:
175 case BPF_PROG_TYPE_CGROUP_DEVICE:
176 case BPF_PROG_TYPE_SK_MSG:
177 case BPF_PROG_TYPE_RAW_TRACEPOINT:
178 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
179 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
180 case BPF_PROG_TYPE_SK_REUSEPORT:
181 case BPF_PROG_TYPE_FLOW_DISSECTOR:
182 case BPF_PROG_TYPE_CGROUP_SYSCTL:
183 case BPF_PROG_TYPE_NETFILTER:
189 fd = bpf_prog_load(prog_type, NULL, "GPL", insns, insns_cnt, &opts);
194 if (fd >= 0 || err != exp_err)
196 if (exp_msg && !strstr(buf, exp_msg))
200 return fd >= 0 ? 1 : 0;
203 int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts)
205 struct bpf_insn insns[] = {
206 BPF_MOV64_IMM(BPF_REG_0, 0),
209 const size_t insn_cnt = ARRAY_SIZE(insns);
213 return libbpf_err(-EINVAL);
215 ret = probe_prog_load(prog_type, insns, insn_cnt, NULL, 0);
216 return libbpf_err(ret);
219 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
220 const char *str_sec, size_t str_len)
222 struct btf_header hdr = {
224 .version = BTF_VERSION,
225 .hdr_len = sizeof(struct btf_header),
226 .type_len = types_len,
227 .str_off = types_len,
233 btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
234 raw_btf = malloc(btf_len);
238 memcpy(raw_btf, &hdr, sizeof(hdr));
239 memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
240 memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
242 btf_fd = bpf_btf_load(raw_btf, btf_len, NULL);
248 static int load_local_storage_btf(void)
250 const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
251 /* struct bpf_spin_lock {
256 * struct bpf_spin_lock l;
261 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
262 /* struct bpf_spin_lock */ /* [2] */
263 BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
264 BTF_MEMBER_ENC(15, 1, 0), /* int val; */
265 /* struct val */ /* [3] */
266 BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
267 BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
268 BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
271 return libbpf__load_raw_btf((char *)types, sizeof(types),
275 static int probe_map_create(enum bpf_map_type map_type)
277 LIBBPF_OPTS(bpf_map_create_opts, opts);
278 int key_size, value_size, max_entries;
279 __u32 btf_key_type_id = 0, btf_value_type_id = 0;
280 int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0;
282 key_size = sizeof(__u32);
283 value_size = sizeof(__u32);
287 case BPF_MAP_TYPE_STACK_TRACE:
288 value_size = sizeof(__u64);
290 case BPF_MAP_TYPE_LPM_TRIE:
291 key_size = sizeof(__u64);
292 value_size = sizeof(__u64);
293 opts.map_flags = BPF_F_NO_PREALLOC;
295 case BPF_MAP_TYPE_CGROUP_STORAGE:
296 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
297 key_size = sizeof(struct bpf_cgroup_storage_key);
298 value_size = sizeof(__u64);
301 case BPF_MAP_TYPE_QUEUE:
302 case BPF_MAP_TYPE_STACK:
305 case BPF_MAP_TYPE_SK_STORAGE:
306 case BPF_MAP_TYPE_INODE_STORAGE:
307 case BPF_MAP_TYPE_TASK_STORAGE:
308 case BPF_MAP_TYPE_CGRP_STORAGE:
310 btf_value_type_id = 3;
313 opts.map_flags = BPF_F_NO_PREALLOC;
314 btf_fd = load_local_storage_btf();
318 case BPF_MAP_TYPE_RINGBUF:
319 case BPF_MAP_TYPE_USER_RINGBUF:
322 max_entries = sysconf(_SC_PAGE_SIZE);
324 case BPF_MAP_TYPE_STRUCT_OPS:
325 /* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */
326 opts.btf_vmlinux_value_type_id = 1;
327 exp_err = -524; /* -ENOTSUPP */
329 case BPF_MAP_TYPE_BLOOM_FILTER:
333 case BPF_MAP_TYPE_HASH:
334 case BPF_MAP_TYPE_ARRAY:
335 case BPF_MAP_TYPE_PROG_ARRAY:
336 case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
337 case BPF_MAP_TYPE_PERCPU_HASH:
338 case BPF_MAP_TYPE_PERCPU_ARRAY:
339 case BPF_MAP_TYPE_CGROUP_ARRAY:
340 case BPF_MAP_TYPE_LRU_HASH:
341 case BPF_MAP_TYPE_LRU_PERCPU_HASH:
342 case BPF_MAP_TYPE_ARRAY_OF_MAPS:
343 case BPF_MAP_TYPE_HASH_OF_MAPS:
344 case BPF_MAP_TYPE_DEVMAP:
345 case BPF_MAP_TYPE_DEVMAP_HASH:
346 case BPF_MAP_TYPE_SOCKMAP:
347 case BPF_MAP_TYPE_CPUMAP:
348 case BPF_MAP_TYPE_XSKMAP:
349 case BPF_MAP_TYPE_SOCKHASH:
350 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
352 case BPF_MAP_TYPE_UNSPEC:
357 if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
358 map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
359 fd_inner = bpf_map_create(BPF_MAP_TYPE_HASH, NULL,
360 sizeof(__u32), sizeof(__u32), 1, NULL);
364 opts.inner_map_fd = fd_inner;
368 opts.btf_fd = btf_fd;
369 opts.btf_key_type_id = btf_key_type_id;
370 opts.btf_value_type_id = btf_value_type_id;
373 fd = bpf_map_create(map_type, NULL, key_size, value_size, max_entries, &opts);
385 return fd < 0 && err == exp_err ? 1 : 0;
387 return fd >= 0 ? 1 : 0;
390 int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts)
395 return libbpf_err(-EINVAL);
397 ret = probe_map_create(map_type);
398 return libbpf_err(ret);
401 int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type, enum bpf_func_id helper_id,
404 struct bpf_insn insns[] = {
405 BPF_EMIT_CALL((__u32)helper_id),
408 const size_t insn_cnt = ARRAY_SIZE(insns);
413 return libbpf_err(-EINVAL);
415 /* we can't successfully load all prog types to check for BPF helper
416 * support, so bail out with -EOPNOTSUPP error
419 case BPF_PROG_TYPE_TRACING:
420 case BPF_PROG_TYPE_EXT:
421 case BPF_PROG_TYPE_LSM:
422 case BPF_PROG_TYPE_STRUCT_OPS:
429 ret = probe_prog_load(prog_type, insns, insn_cnt, buf, sizeof(buf));
431 return libbpf_err(ret);
433 /* If BPF verifier doesn't recognize BPF helper ID (enum bpf_func_id)
434 * at all, it will emit something like "invalid func unknown#181".
435 * If BPF verifier recognizes BPF helper but it's not supported for
436 * given BPF program type, it will emit "unknown func bpf_sys_bpf#166".
437 * In both cases, provided combination of BPF program type and BPF
438 * helper is not supported by the kernel.
439 * In all other cases, probe_prog_load() above will either succeed (e.g.,
440 * because BPF helper happens to accept no input arguments or it
441 * accepts one input argument and initial PTR_TO_CTX is fine for
442 * that), or we'll get some more specific BPF verifier error about
443 * some unsatisfied conditions.
445 if (ret == 0 && (strstr(buf, "invalid func ") || strstr(buf, "unknown func ")))
447 return 1; /* assume supported */