[linux-block.git] / tools / lib / bpf / libbpf_probes.c

// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (c) 2019 Netronome Systems, Inc. */

#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/utsname.h>

#include <linux/btf.h>
#include <linux/filter.h>
#include <linux/kernel.h>
#include <linux/version.h>

#include "bpf.h"
#include "libbpf.h"
#include "libbpf_internal.h"

/* On Ubuntu LINUX_VERSION_CODE doesn't correspond to info.release,
 * but Ubuntu provides /proc/version_signature file, as described at
 * https://ubuntu.com/kernel, with an example contents below, which we
 * can use to get a proper LINUX_VERSION_CODE.
 *
 *   Ubuntu 5.4.0-12.15-generic 5.4.8
 *
 * In the above, 5.4.8 is what kernel is actually expecting, while
 * uname() call will return 5.4.0 in info.release.
 */
static __u32 get_ubuntu_kernel_version(void)
{
	const char *ubuntu_kver_file = "/proc/version_signature";
	__u32 major, minor, patch;
	int ret;
	FILE *f;

	if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) != 0)
		return 0;

	f = fopen(ubuntu_kver_file, "re");
	if (!f)
		return 0;

	ret = fscanf(f, "%*s %*s %u.%u.%u\n", &major, &minor, &patch);
	fclose(f);
	if (ret != 3)
		return 0;

	return KERNEL_VERSION(major, minor, patch);
}

/* On Debian LINUX_VERSION_CODE doesn't correspond to info.release.
 * Instead, it is provided in info.version. An example content of
 * Debian 10 looks like the below.
 *
 *   utsname::release   4.19.0-22-amd64
 *   utsname::version   #1 SMP Debian 4.19.260-1 (2022-09-29)
 *
 * In the above, 4.19.260 is what kernel is actually expecting, while
 * uname() call will return 4.19.0 in info.release.
 */
static __u32 get_debian_kernel_version(struct utsname *info)
{
	__u32 major, minor, patch;
	char *p;

	p = strstr(info->version, "Debian ");
	if (!p) {
		/* This is not a Debian kernel. */
		return 0;
	}

	if (sscanf(p, "Debian %u.%u.%u", &major, &minor, &patch) != 3)
		return 0;

	return KERNEL_VERSION(major, minor, patch);
}

__u32 get_kernel_version(void)
{
	__u32 major, minor, patch, version;
	struct utsname info;

	/* Check if this is an Ubuntu kernel. */
	version = get_ubuntu_kernel_version();
	if (version != 0)
		return version;

	uname(&info);

	/* Check if this is a Debian kernel. */
	version = get_debian_kernel_version(&info);
	if (version != 0)
		return version;

	if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
		return 0;

	return KERNEL_VERSION(major, minor, patch);
}

static int probe_prog_load(enum bpf_prog_type prog_type,
			   const struct bpf_insn *insns, size_t insns_cnt,
			   char *log_buf, size_t log_buf_sz)
{
	LIBBPF_OPTS(bpf_prog_load_opts, opts,
		.log_buf = log_buf,
		.log_size = log_buf_sz,
		.log_level = log_buf ? 1 : 0,
	);
	int fd, err, exp_err = 0;
	const char *exp_msg = NULL;
	char buf[4096];

	switch (prog_type) {
	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
		opts.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
		break;
	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
		opts.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
		break;
	case BPF_PROG_TYPE_SK_LOOKUP:
		opts.expected_attach_type = BPF_SK_LOOKUP;
		break;
	case BPF_PROG_TYPE_KPROBE:
		opts.kern_version = get_kernel_version();
		break;
	case BPF_PROG_TYPE_LIRC_MODE2:
		opts.expected_attach_type = BPF_LIRC_MODE2;
		break;
	case BPF_PROG_TYPE_TRACING:
	case BPF_PROG_TYPE_LSM:
		opts.log_buf = buf;
		opts.log_size = sizeof(buf);
		opts.log_level = 1;
		if (prog_type == BPF_PROG_TYPE_TRACING)
			opts.expected_attach_type = BPF_TRACE_FENTRY;
		else
			opts.expected_attach_type = BPF_MODIFY_RETURN;
		opts.attach_btf_id = 1;

		exp_err = -EINVAL;
		exp_msg = "attach_btf_id 1 is not a function";
		break;
	case BPF_PROG_TYPE_EXT:
		opts.log_buf = buf;
		opts.log_size = sizeof(buf);
		opts.log_level = 1;
		opts.attach_btf_id = 1;

		exp_err = -EINVAL;
		exp_msg = "Cannot replace kernel functions";
		break;
	case BPF_PROG_TYPE_SYSCALL:
		opts.prog_flags = BPF_F_SLEEPABLE;
		break;
	case BPF_PROG_TYPE_STRUCT_OPS:
		exp_err = -524; /* -ENOTSUPP */
		break;
	case BPF_PROG_TYPE_UNSPEC:
	case BPF_PROG_TYPE_SOCKET_FILTER:
	case BPF_PROG_TYPE_SCHED_CLS:
	case BPF_PROG_TYPE_SCHED_ACT:
	case BPF_PROG_TYPE_TRACEPOINT:
	case BPF_PROG_TYPE_XDP:
	case BPF_PROG_TYPE_PERF_EVENT:
	case BPF_PROG_TYPE_CGROUP_SKB:
	case BPF_PROG_TYPE_CGROUP_SOCK:
	case BPF_PROG_TYPE_LWT_IN:
	case BPF_PROG_TYPE_LWT_OUT:
	case BPF_PROG_TYPE_LWT_XMIT:
	case BPF_PROG_TYPE_SOCK_OPS:
	case BPF_PROG_TYPE_SK_SKB:
	case BPF_PROG_TYPE_CGROUP_DEVICE:
	case BPF_PROG_TYPE_SK_MSG:
	case BPF_PROG_TYPE_RAW_TRACEPOINT:
	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
	case BPF_PROG_TYPE_SK_REUSEPORT:
	case BPF_PROG_TYPE_FLOW_DISSECTOR:
	case BPF_PROG_TYPE_CGROUP_SYSCTL:
		break;
	case BPF_PROG_TYPE_NETFILTER:
		opts.expected_attach_type = BPF_NETFILTER;
		break;
	default:
		return -EOPNOTSUPP;
	}

	fd = bpf_prog_load(prog_type, NULL, "GPL", insns, insns_cnt, &opts);
	err = -errno;
	if (fd >= 0)
		close(fd);
	if (exp_err) {
		if (fd >= 0 || err != exp_err)
			return 0;
		if (exp_msg && !strstr(buf, exp_msg))
			return 0;
		return 1;
	}
	return fd >= 0 ? 1 : 0;
}

int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts)
{
	struct bpf_insn insns[] = {
		BPF_MOV64_IMM(BPF_REG_0, 0),
		BPF_EXIT_INSN()
	};
	const size_t insn_cnt = ARRAY_SIZE(insns);
	int ret;

	if (opts)
		return libbpf_err(-EINVAL);

	ret = probe_prog_load(prog_type, insns, insn_cnt, NULL, 0);
	return libbpf_err(ret);
}

int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
			 const char *str_sec, size_t str_len,
			 int token_fd)
{
	struct btf_header hdr = {
		.magic = BTF_MAGIC,
		.version = BTF_VERSION,
		.hdr_len = sizeof(struct btf_header),
		.type_len = types_len,
		.str_off = types_len,
		.str_len = str_len,
	};
	LIBBPF_OPTS(bpf_btf_load_opts, opts,
		.token_fd = token_fd,
		.btf_flags = token_fd ? BPF_F_TOKEN_FD : 0,
	);
	int btf_fd, btf_len;
	__u8 *raw_btf;

	btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
	raw_btf = malloc(btf_len);
	if (!raw_btf)
		return -ENOMEM;

	memcpy(raw_btf, &hdr, sizeof(hdr));
	memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
	memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);

	btf_fd = bpf_btf_load(raw_btf, btf_len, &opts);

	free(raw_btf);
	return btf_fd;
}

static int load_local_storage_btf(void)
{
	const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
	/* struct bpf_spin_lock {
	 *   int val;
	 * };
	 * struct val {
	 *   int cnt;
	 *   struct bpf_spin_lock l;
	 * };
	 */
	__u32 types[] = {
		/* int */
		BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4),  /* [1] */
		/* struct bpf_spin_lock */                      /* [2] */
		BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
		BTF_MEMBER_ENC(15, 1, 0), /* int val; */
		/* struct val */                                /* [3] */
		BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
		BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
		BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
	};

	return libbpf__load_raw_btf((char *)types, sizeof(types),
				     strs, sizeof(strs), 0);
}

static int probe_map_create(enum bpf_map_type map_type)
{
	LIBBPF_OPTS(bpf_map_create_opts, opts);
	int key_size, value_size, max_entries;
	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0;

	key_size	= sizeof(__u32);
	value_size	= sizeof(__u32);
	max_entries	= 1;

	switch (map_type) {
	case BPF_MAP_TYPE_STACK_TRACE:
		value_size	= sizeof(__u64);
		break;
	case BPF_MAP_TYPE_LPM_TRIE:
		key_size	= sizeof(__u64);
		value_size	= sizeof(__u64);
		opts.map_flags	= BPF_F_NO_PREALLOC;
		break;
	case BPF_MAP_TYPE_CGROUP_STORAGE:
	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
		key_size	= sizeof(struct bpf_cgroup_storage_key);
		value_size	= sizeof(__u64);
		max_entries	= 0;
		break;
	case BPF_MAP_TYPE_QUEUE:
	case BPF_MAP_TYPE_STACK:
		key_size	= 0;
		break;
	case BPF_MAP_TYPE_SK_STORAGE:
	case BPF_MAP_TYPE_INODE_STORAGE:
	case BPF_MAP_TYPE_TASK_STORAGE:
	case BPF_MAP_TYPE_CGRP_STORAGE:
		btf_key_type_id = 1;
		btf_value_type_id = 3;
		value_size = 8;
		max_entries = 0;
		opts.map_flags = BPF_F_NO_PREALLOC;
		btf_fd = load_local_storage_btf();
		if (btf_fd < 0)
			return btf_fd;
		break;
	case BPF_MAP_TYPE_RINGBUF:
	case BPF_MAP_TYPE_USER_RINGBUF:
		key_size = 0;
		value_size = 0;
		max_entries = sysconf(_SC_PAGE_SIZE);
		break;
	case BPF_MAP_TYPE_STRUCT_OPS:
		/* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */
		opts.btf_vmlinux_value_type_id = 1;
		opts.value_type_btf_obj_fd = -1;
		exp_err = -524; /* -ENOTSUPP */
		break;
	case BPF_MAP_TYPE_BLOOM_FILTER:
		key_size = 0;
		max_entries = 1;
		break;
	case BPF_MAP_TYPE_ARENA:
		key_size	= 0;
		value_size	= 0;
		max_entries	= 1; /* one page */
		opts.map_extra	= 0; /* can mmap() at any address */
		opts.map_flags	= BPF_F_MMAPABLE;
		break;
	case BPF_MAP_TYPE_HASH:
	case BPF_MAP_TYPE_ARRAY:
	case BPF_MAP_TYPE_PROG_ARRAY:
	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
	case BPF_MAP_TYPE_PERCPU_HASH:
	case BPF_MAP_TYPE_PERCPU_ARRAY:
	case BPF_MAP_TYPE_CGROUP_ARRAY:
	case BPF_MAP_TYPE_LRU_HASH:
	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
	case BPF_MAP_TYPE_HASH_OF_MAPS:
	case BPF_MAP_TYPE_DEVMAP:
	case BPF_MAP_TYPE_DEVMAP_HASH:
	case BPF_MAP_TYPE_SOCKMAP:
	case BPF_MAP_TYPE_CPUMAP:
	case BPF_MAP_TYPE_XSKMAP:
	case BPF_MAP_TYPE_SOCKHASH:
	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
		break;
	case BPF_MAP_TYPE_UNSPEC:
	default:
		return -EOPNOTSUPP;
	}

	if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
	    map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
		fd_inner = bpf_map_create(BPF_MAP_TYPE_HASH, NULL,
					  sizeof(__u32), sizeof(__u32), 1, NULL);
		if (fd_inner < 0)
			goto cleanup;

		opts.inner_map_fd = fd_inner;
	}

	if (btf_fd >= 0) {
		opts.btf_fd = btf_fd;
		opts.btf_key_type_id = btf_key_type_id;
		opts.btf_value_type_id = btf_value_type_id;
	}

	fd = bpf_map_create(map_type, NULL, key_size, value_size, max_entries, &opts);
	err = -errno;

cleanup:
	if (fd >= 0)
		close(fd);
	if (fd_inner >= 0)
		close(fd_inner);
	if (btf_fd >= 0)
		close(btf_fd);

	if (exp_err)
		return fd < 0 && err == exp_err ? 1 : 0;
	else
		return fd >= 0 ? 1 : 0;
}

int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts)
{
	int ret;

	if (opts)
		return libbpf_err(-EINVAL);

	ret = probe_map_create(map_type);
	return libbpf_err(ret);
}

int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type, enum bpf_func_id helper_id,
			    const void *opts)
{
	struct bpf_insn insns[] = {
		BPF_EMIT_CALL((__u32)helper_id),
		BPF_EXIT_INSN(),
	};
	const size_t insn_cnt = ARRAY_SIZE(insns);
	char buf[4096];
	int ret;

	if (opts)
		return libbpf_err(-EINVAL);

	/* we can't successfully load all prog types to check for BPF helper
	 * support, so bail out with -EOPNOTSUPP error
	 */
	switch (prog_type) {
	case BPF_PROG_TYPE_TRACING:
	case BPF_PROG_TYPE_EXT:
	case BPF_PROG_TYPE_LSM:
	case BPF_PROG_TYPE_STRUCT_OPS:
		return -EOPNOTSUPP;
	default:
		break;
	}

	buf[0] = '\0';
	ret = probe_prog_load(prog_type, insns, insn_cnt, buf, sizeof(buf));
	if (ret < 0)
		return libbpf_err(ret);

	/* If BPF verifier doesn't recognize BPF helper ID (enum bpf_func_id)
	 * at all, it will emit something like "invalid func unknown#181".
	 * If BPF verifier recognizes BPF helper but it's not supported for
	 * given BPF program type, it will emit "unknown func bpf_sys_bpf#166"
	 * or "program of this type cannot use helper bpf_sys_bpf#166".
	 * In both cases, provided combination of BPF program type and BPF
	 * helper is not supported by the kernel.
	 * In all other cases, probe_prog_load() above will either succeed (e.g.,
	 * because BPF helper happens to accept no input arguments or it
	 * accepts one input argument and initial PTR_TO_CTX is fine for
	 * that), or we'll get some more specific BPF verifier error about
	 * some unsatisfied conditions.
	 */
	if (ret == 0 && (strstr(buf, "invalid func ") || strstr(buf, "unknown func ") ||
			 strstr(buf, "program of this type cannot use helper ")))
		return 0;
	return 1; /* assume supported */
}
Commit	Line	Data
	1	// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
	2	/* Copyright (c) 2019 Netronome Systems, Inc. */
	3
	4	#include <errno.h>
	5	#include <fcntl.h>
	6	#include <string.h>
	7	#include <stdlib.h>
	8	#include <unistd.h>
	9	#include <net/if.h>
	10	#include <sys/utsname.h>
	11
	12	#include <linux/btf.h>
	13	#include <linux/filter.h>
	14	#include <linux/kernel.h>
	15	#include <linux/version.h>
	16
	17	#include "bpf.h"
	18	#include "libbpf.h"
	19	#include "libbpf_internal.h"
	20
	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.
	25	*
	26	* Ubuntu 5.4.0-12.15-generic 5.4.8
	27	*
	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.
	30	*/
	31	static __u32 get_ubuntu_kernel_version(void)
	32	{
	33	const char *ubuntu_kver_file = "/proc/version_signature";
	34	__u32 major, minor, patch;
	35	int ret;
	36	FILE *f;
	37
	38	if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) != 0)
	39	return 0;
	40
	41	f = fopen(ubuntu_kver_file, "re");
	42	if (!f)
	43	return 0;
	44
	45	ret = fscanf(f, "%s %s %u.%u.%u\n", &major, &minor, &patch);
	46	fclose(f);
	47	if (ret != 3)
	48	return 0;
	49
	50	return KERNEL_VERSION(major, minor, patch);
	51	}
	52
	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.
	56	*
	57	* utsname::release 4.19.0-22-amd64
	58	* utsname::version #1 SMP Debian 4.19.260-1 (2022-09-29)
	59	*
	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.
	62	*/
	63	static __u32 get_debian_kernel_version(struct utsname *info)
	64	{
	65	__u32 major, minor, patch;
	66	char *p;
	67
	68	p = strstr(info->version, "Debian ");
	69	if (!p) {
	70	/* This is not a Debian kernel. */
	71	return 0;
	72	}
	73
	74	if (sscanf(p, "Debian %u.%u.%u", &major, &minor, &patch) != 3)
	75	return 0;
	76
	77	return KERNEL_VERSION(major, minor, patch);
	78	}
	79
	80	__u32 get_kernel_version(void)
	81	{
	82	__u32 major, minor, patch, version;
	83	struct utsname info;
	84
	85	/* Check if this is an Ubuntu kernel. */
	86	version = get_ubuntu_kernel_version();
	87	if (version != 0)
	88	return version;
	89
	90	uname(&info);
	91
	92	/* Check if this is a Debian kernel. */
	93	version = get_debian_kernel_version(&info);
	94	if (version != 0)
	95	return version;
	96
	97	if (sscanf(info.release, "%u.%u.%u", &major, &minor, &patch) != 3)
	98	return 0;
	99
	100	return KERNEL_VERSION(major, minor, patch);
	101	}
	102
	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)
	106	{
	107	LIBBPF_OPTS(bpf_prog_load_opts, opts,
	108	.log_buf = log_buf,
	109	.log_size = log_buf_sz,
	110	.log_level = log_buf ? 1 : 0,
	111	);
	112	int fd, err, exp_err = 0;
	113	const char *exp_msg = NULL;
	114	char buf[4096];
	115
	116	switch (prog_type) {
	117	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
	118	opts.expected_attach_type = BPF_CGROUP_INET4_CONNECT;
	119	break;
	120	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
	121	opts.expected_attach_type = BPF_CGROUP_GETSOCKOPT;
	122	break;
	123	case BPF_PROG_TYPE_SK_LOOKUP:
	124	opts.expected_attach_type = BPF_SK_LOOKUP;
	125	break;
	126	case BPF_PROG_TYPE_KPROBE:
	127	opts.kern_version = get_kernel_version();
	128	break;
	129	case BPF_PROG_TYPE_LIRC_MODE2:
	130	opts.expected_attach_type = BPF_LIRC_MODE2;
	131	break;
	132	case BPF_PROG_TYPE_TRACING:
	133	case BPF_PROG_TYPE_LSM:
	134	opts.log_buf = buf;
	135	opts.log_size = sizeof(buf);
	136	opts.log_level = 1;
	137	if (prog_type == BPF_PROG_TYPE_TRACING)
	138	opts.expected_attach_type = BPF_TRACE_FENTRY;
	139	else
	140	opts.expected_attach_type = BPF_MODIFY_RETURN;
	141	opts.attach_btf_id = 1;
	142
	143	exp_err = -EINVAL;
	144	exp_msg = "attach_btf_id 1 is not a function";
	145	break;
	146	case BPF_PROG_TYPE_EXT:
	147	opts.log_buf = buf;
	148	opts.log_size = sizeof(buf);
	149	opts.log_level = 1;
	150	opts.attach_btf_id = 1;
	151
	152	exp_err = -EINVAL;
	153	exp_msg = "Cannot replace kernel functions";
	154	break;
	155	case BPF_PROG_TYPE_SYSCALL:
	156	opts.prog_flags = BPF_F_SLEEPABLE;
	157	break;
	158	case BPF_PROG_TYPE_STRUCT_OPS:
	159	exp_err = -524; /* -ENOTSUPP */
	160	break;
	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	break;
	184	case BPF_PROG_TYPE_NETFILTER:
	185	opts.expected_attach_type = BPF_NETFILTER;
	186	break;
	187	default:
	188	return -EOPNOTSUPP;
	189	}
	190
	191	fd = bpf_prog_load(prog_type, NULL, "GPL", insns, insns_cnt, &opts);
	192	err = -errno;
	193	if (fd >= 0)
	194	close(fd);
	195	if (exp_err) {
	196	if (fd >= 0 \|\| err != exp_err)
	197	return 0;
	198	if (exp_msg && !strstr(buf, exp_msg))
	199	return 0;
	200	return 1;
	201	}
	202	return fd >= 0 ? 1 : 0;
	203	}
	204
	205	int libbpf_probe_bpf_prog_type(enum bpf_prog_type prog_type, const void *opts)
	206	{
	207	struct bpf_insn insns[] = {
	208	BPF_MOV64_IMM(BPF_REG_0, 0),
	209	BPF_EXIT_INSN()
	210	};
	211	const size_t insn_cnt = ARRAY_SIZE(insns);
	212	int ret;
	213
	214	if (opts)
	215	return libbpf_err(-EINVAL);
	216
	217	ret = probe_prog_load(prog_type, insns, insn_cnt, NULL, 0);
	218	return libbpf_err(ret);
	219	}
	220
	221	int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
	222	const char *str_sec, size_t str_len,
	223	int token_fd)
	224	{
	225	struct btf_header hdr = {
	226	.magic = BTF_MAGIC,
	227	.version = BTF_VERSION,
	228	.hdr_len = sizeof(struct btf_header),
	229	.type_len = types_len,
	230	.str_off = types_len,
	231	.str_len = str_len,
	232	};
	233	LIBBPF_OPTS(bpf_btf_load_opts, opts,
	234	.token_fd = token_fd,
	235	.btf_flags = token_fd ? BPF_F_TOKEN_FD : 0,
	236	);
	237	int btf_fd, btf_len;
	238	__u8 *raw_btf;
	239
	240	btf_len = hdr.hdr_len + hdr.type_len + hdr.str_len;
	241	raw_btf = malloc(btf_len);
	242	if (!raw_btf)
	243	return -ENOMEM;
	244
	245	memcpy(raw_btf, &hdr, sizeof(hdr));
	246	memcpy(raw_btf + hdr.hdr_len, raw_types, hdr.type_len);
	247	memcpy(raw_btf + hdr.hdr_len + hdr.type_len, str_sec, hdr.str_len);
	248
	249	btf_fd = bpf_btf_load(raw_btf, btf_len, &opts);
	250
	251	free(raw_btf);
	252	return btf_fd;
	253	}
	254
	255	static int load_local_storage_btf(void)
	256	{
	257	const char strs[] = "\0bpf_spin_lock\0val\0cnt\0l";
	258	/* struct bpf_spin_lock {
	259	* int val;
	260	* };
	261	* struct val {
	262	* int cnt;
	263	* struct bpf_spin_lock l;
	264	* };
	265	*/
	266	__u32 types[] = {
	267	/* int */
	268	BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
	269	/* struct bpf_spin_lock / / [2] */
	270	BTF_TYPE_ENC(1, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 4),
	271	BTF_MEMBER_ENC(15, 1, 0), /* int val; */
	272	/* struct val / / [3] */
	273	BTF_TYPE_ENC(15, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 2), 8),
	274	BTF_MEMBER_ENC(19, 1, 0), /* int cnt; */
	275	BTF_MEMBER_ENC(23, 2, 32),/* struct bpf_spin_lock l; */
	276	};
	277
	278	return libbpf__load_raw_btf((char *)types, sizeof(types),
	279	strs, sizeof(strs), 0);
	280	}
	281
	282	static int probe_map_create(enum bpf_map_type map_type)
	283	{
	284	LIBBPF_OPTS(bpf_map_create_opts, opts);
	285	int key_size, value_size, max_entries;
	286	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
	287	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0;
	288
	289	key_size = sizeof(__u32);
	290	value_size = sizeof(__u32);
	291	max_entries = 1;
	292
	293	switch (map_type) {
	294	case BPF_MAP_TYPE_STACK_TRACE:
	295	value_size = sizeof(__u64);
	296	break;
	297	case BPF_MAP_TYPE_LPM_TRIE:
	298	key_size = sizeof(__u64);
	299	value_size = sizeof(__u64);
	300	opts.map_flags = BPF_F_NO_PREALLOC;
	301	break;
	302	case BPF_MAP_TYPE_CGROUP_STORAGE:
	303	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
	304	key_size = sizeof(struct bpf_cgroup_storage_key);
	305	value_size = sizeof(__u64);
	306	max_entries = 0;
	307	break;
	308	case BPF_MAP_TYPE_QUEUE:
	309	case BPF_MAP_TYPE_STACK:
	310	key_size = 0;
	311	break;
	312	case BPF_MAP_TYPE_SK_STORAGE:
	313	case BPF_MAP_TYPE_INODE_STORAGE:
	314	case BPF_MAP_TYPE_TASK_STORAGE:
	315	case BPF_MAP_TYPE_CGRP_STORAGE:
	316	btf_key_type_id = 1;
	317	btf_value_type_id = 3;
	318	value_size = 8;
	319	max_entries = 0;
	320	opts.map_flags = BPF_F_NO_PREALLOC;
	321	btf_fd = load_local_storage_btf();
	322	if (btf_fd < 0)
	323	return btf_fd;
	324	break;
	325	case BPF_MAP_TYPE_RINGBUF:
	326	case BPF_MAP_TYPE_USER_RINGBUF:
	327	key_size = 0;
	328	value_size = 0;
	329	max_entries = sysconf(_SC_PAGE_SIZE);
	330	break;
	331	case BPF_MAP_TYPE_STRUCT_OPS:
	332	/* we'll get -ENOTSUPP for invalid BTF type ID for struct_ops */
	333	opts.btf_vmlinux_value_type_id = 1;
	334	opts.value_type_btf_obj_fd = -1;
	335	exp_err = -524; /* -ENOTSUPP */
	336	break;
	337	case BPF_MAP_TYPE_BLOOM_FILTER:
	338	key_size = 0;
	339	max_entries = 1;
	340	break;
	341	case BPF_MAP_TYPE_ARENA:
	342	key_size = 0;
	343	value_size = 0;
	344	max_entries = 1; /* one page */
	345	opts.map_extra = 0; /* can mmap() at any address */
	346	opts.map_flags = BPF_F_MMAPABLE;
	347	break;
	348	case BPF_MAP_TYPE_HASH:
	349	case BPF_MAP_TYPE_ARRAY:
	350	case BPF_MAP_TYPE_PROG_ARRAY:
	351	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
	352	case BPF_MAP_TYPE_PERCPU_HASH:
	353	case BPF_MAP_TYPE_PERCPU_ARRAY:
	354	case BPF_MAP_TYPE_CGROUP_ARRAY:
	355	case BPF_MAP_TYPE_LRU_HASH:
	356	case BPF_MAP_TYPE_LRU_PERCPU_HASH:
	357	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
	358	case BPF_MAP_TYPE_HASH_OF_MAPS:
	359	case BPF_MAP_TYPE_DEVMAP:
	360	case BPF_MAP_TYPE_DEVMAP_HASH:
	361	case BPF_MAP_TYPE_SOCKMAP:
	362	case BPF_MAP_TYPE_CPUMAP:
	363	case BPF_MAP_TYPE_XSKMAP:
	364	case BPF_MAP_TYPE_SOCKHASH:
	365	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
	366	break;
	367	case BPF_MAP_TYPE_UNSPEC:
	368	default:
	369	return -EOPNOTSUPP;
	370	}
	371
	372	if (map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS \|\|
	373	map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
	374	fd_inner = bpf_map_create(BPF_MAP_TYPE_HASH, NULL,
	375	sizeof(__u32), sizeof(__u32), 1, NULL);
	376	if (fd_inner < 0)
	377	goto cleanup;
	378
	379	opts.inner_map_fd = fd_inner;
	380	}
	381
	382	if (btf_fd >= 0) {
	383	opts.btf_fd = btf_fd;
	384	opts.btf_key_type_id = btf_key_type_id;
	385	opts.btf_value_type_id = btf_value_type_id;
	386	}
	387
	388	fd = bpf_map_create(map_type, NULL, key_size, value_size, max_entries, &opts);
	389	err = -errno;
	390
	391	cleanup:
	392	if (fd >= 0)
	393	close(fd);
	394	if (fd_inner >= 0)
	395	close(fd_inner);
	396	if (btf_fd >= 0)
	397	close(btf_fd);
	398
	399	if (exp_err)
	400	return fd < 0 && err == exp_err ? 1 : 0;
	401	else
	402	return fd >= 0 ? 1 : 0;
	403	}
	404
	405	int libbpf_probe_bpf_map_type(enum bpf_map_type map_type, const void *opts)
	406	{
	407	int ret;
	408
	409	if (opts)
	410	return libbpf_err(-EINVAL);
	411
	412	ret = probe_map_create(map_type);
	413	return libbpf_err(ret);
	414	}
	415
	416	int libbpf_probe_bpf_helper(enum bpf_prog_type prog_type, enum bpf_func_id helper_id,
	417	const void *opts)
	418	{
	419	struct bpf_insn insns[] = {
	420	BPF_EMIT_CALL((__u32)helper_id),
	421	BPF_EXIT_INSN(),
	422	};
	423	const size_t insn_cnt = ARRAY_SIZE(insns);
	424	char buf[4096];
	425	int ret;
	426
	427	if (opts)
	428	return libbpf_err(-EINVAL);
	429
	430	/* we can't successfully load all prog types to check for BPF helper
	431	* support, so bail out with -EOPNOTSUPP error
	432	*/
	433	switch (prog_type) {
	434	case BPF_PROG_TYPE_TRACING:
	435	case BPF_PROG_TYPE_EXT:
	436	case BPF_PROG_TYPE_LSM:
	437	case BPF_PROG_TYPE_STRUCT_OPS:
	438	return -EOPNOTSUPP;
	439	default:
	440	break;
	441	}
	442
	443	buf[0] = '\0';
	444	ret = probe_prog_load(prog_type, insns, insn_cnt, buf, sizeof(buf));
	445	if (ret < 0)
	446	return libbpf_err(ret);
	447
	448	/* If BPF verifier doesn't recognize BPF helper ID (enum bpf_func_id)
	449	* at all, it will emit something like "invalid func unknown#181".
	450	* If BPF verifier recognizes BPF helper but it's not supported for
	451	* given BPF program type, it will emit "unknown func bpf_sys_bpf#166"
	452	* or "program of this type cannot use helper bpf_sys_bpf#166".
	453	* In both cases, provided combination of BPF program type and BPF
	454	* helper is not supported by the kernel.
	455	* In all other cases, probe_prog_load() above will either succeed (e.g.,
	456	* because BPF helper happens to accept no input arguments or it
	457	* accepts one input argument and initial PTR_TO_CTX is fine for
	458	* that), or we'll get some more specific BPF verifier error about
	459	* some unsatisfied conditions.
	460	*/
	461	if (ret == 0 && (strstr(buf, "invalid func ") \|\| strstr(buf, "unknown func ") \|\|
	462	strstr(buf, "program of this type cannot use helper ")))
	463	return 0;
	464	return 1; /* assume supported */
	465	}