1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ 2 3 /* 4 * Internal libbpf helpers. 5 * 6 * Copyright (c) 2019 Facebook 7 */ 8 9 #ifndef __LIBBPF_LIBBPF_INTERNAL_H 10 #define __LIBBPF_LIBBPF_INTERNAL_H 11 12 #include "libbpf.h" 13 14 #define BTF_INFO_ENC(kind, kind_flag, vlen) \ 15 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) 16 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type) 17 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ 18 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) 19 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ 20 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ 21 BTF_INT_ENC(encoding, bits_offset, bits) 22 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset) 23 #define BTF_PARAM_ENC(name, type) (name), (type) 24 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size) 25 26 #ifndef min 27 # define min(x, y) ((x) < (y) ? (x) : (y)) 28 #endif 29 #ifndef max 30 # define max(x, y) ((x) < (y) ? (y) : (x)) 31 #endif 32 #ifndef offsetofend 33 # define offsetofend(TYPE, FIELD) \ 34 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) 35 #endif 36 37 /* Symbol versioning is different between static and shared library. 38 * Properly versioned symbols are needed for shared library, but 39 * only the symbol of the new version is needed for static library. 40 */ 41 #ifdef SHARED 42 # define COMPAT_VERSION(internal_name, api_name, version) \ 43 asm(".symver " #internal_name "," #api_name "@" #version); 44 # define DEFAULT_VERSION(internal_name, api_name, version) \ 45 asm(".symver " #internal_name "," #api_name "@@" #version); 46 #else 47 # define COMPAT_VERSION(internal_name, api_name, version) 48 # define DEFAULT_VERSION(internal_name, api_name, version) \ 49 extern typeof(internal_name) api_name \ 50 __attribute__((alias(#internal_name))); 51 #endif 52 53 extern void libbpf_print(enum libbpf_print_level level, 54 const char *format, ...) 55 __attribute__((format(printf, 2, 3))); 56 57 #define __pr(level, fmt, ...) \ 58 do { \ 59 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \ 60 } while (0) 61 62 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__) 63 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__) 64 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__) 65 66 static inline bool libbpf_validate_opts(const char *opts, 67 size_t opts_sz, size_t user_sz, 68 const char *type_name) 69 { 70 if (user_sz < sizeof(size_t)) { 71 pr_warn("%s size (%zu) is too small\n", type_name, user_sz); 72 return false; 73 } 74 if (user_sz > opts_sz) { 75 size_t i; 76 77 for (i = opts_sz; i < user_sz; i++) { 78 if (opts[i]) { 79 pr_warn("%s has non-zero extra bytes\n", 80 type_name); 81 return false; 82 } 83 } 84 } 85 return true; 86 } 87 88 #define OPTS_VALID(opts, type) \ 89 (!(opts) || libbpf_validate_opts((const char *)opts, \ 90 offsetofend(struct type, \ 91 type##__last_field), \ 92 (opts)->sz, #type)) 93 #define OPTS_HAS(opts, field) \ 94 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field)) 95 #define OPTS_GET(opts, field, fallback_value) \ 96 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value) 97 98 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz); 99 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz); 100 int libbpf__load_raw_btf(const char *raw_types, size_t types_len, 101 const char *str_sec, size_t str_len); 102 103 int bpf_object__section_size(const struct bpf_object *obj, const char *name, 104 __u32 *size); 105 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name, 106 __u32 *off); 107 108 struct nlattr; 109 typedef int (*libbpf_dump_nlmsg_t)(void *cookie, void *msg, struct nlattr **tb); 110 int libbpf_netlink_open(unsigned int *nl_pid); 111 int libbpf_nl_get_link(int sock, unsigned int nl_pid, 112 libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie); 113 int libbpf_nl_get_class(int sock, unsigned int nl_pid, int ifindex, 114 libbpf_dump_nlmsg_t dump_class_nlmsg, void *cookie); 115 int libbpf_nl_get_qdisc(int sock, unsigned int nl_pid, int ifindex, 116 libbpf_dump_nlmsg_t dump_qdisc_nlmsg, void *cookie); 117 int libbpf_nl_get_filter(int sock, unsigned int nl_pid, int ifindex, int handle, 118 libbpf_dump_nlmsg_t dump_filter_nlmsg, void *cookie); 119 120 struct btf_ext_info { 121 /* 122 * info points to the individual info section (e.g. func_info and 123 * line_info) from the .BTF.ext. It does not include the __u32 rec_size. 124 */ 125 void *info; 126 __u32 rec_size; 127 __u32 len; 128 }; 129 130 #define for_each_btf_ext_sec(seg, sec) \ 131 for (sec = (seg)->info; \ 132 (void *)sec < (seg)->info + (seg)->len; \ 133 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \ 134 (seg)->rec_size * sec->num_info) 135 136 #define for_each_btf_ext_rec(seg, sec, i, rec) \ 137 for (i = 0, rec = (void *)&(sec)->data; \ 138 i < (sec)->num_info; \ 139 i++, rec = (void *)rec + (seg)->rec_size) 140 141 struct btf_ext { 142 union { 143 struct btf_ext_header *hdr; 144 void *data; 145 }; 146 struct btf_ext_info func_info; 147 struct btf_ext_info line_info; 148 struct btf_ext_info field_reloc_info; 149 __u32 data_size; 150 }; 151 152 struct btf_ext_info_sec { 153 __u32 sec_name_off; 154 __u32 num_info; 155 /* Followed by num_info * record_size number of bytes */ 156 __u8 data[0]; 157 }; 158 159 /* The minimum bpf_func_info checked by the loader */ 160 struct bpf_func_info_min { 161 __u32 insn_off; 162 __u32 type_id; 163 }; 164 165 /* The minimum bpf_line_info checked by the loader */ 166 struct bpf_line_info_min { 167 __u32 insn_off; 168 __u32 file_name_off; 169 __u32 line_off; 170 __u32 line_col; 171 }; 172 173 /* bpf_field_info_kind encodes which aspect of captured field has to be 174 * adjusted by relocations. Currently supported values are: 175 * - BPF_FIELD_BYTE_OFFSET: field offset (in bytes); 176 * - BPF_FIELD_EXISTS: field existence (1, if field exists; 0, otherwise); 177 */ 178 enum bpf_field_info_kind { 179 BPF_FIELD_BYTE_OFFSET = 0, /* field byte offset */ 180 BPF_FIELD_BYTE_SIZE = 1, 181 BPF_FIELD_EXISTS = 2, /* field existence in target kernel */ 182 BPF_FIELD_SIGNED = 3, 183 BPF_FIELD_LSHIFT_U64 = 4, 184 BPF_FIELD_RSHIFT_U64 = 5, 185 }; 186 187 /* The minimum bpf_field_reloc checked by the loader 188 * 189 * Field relocation captures the following data: 190 * - insn_off - instruction offset (in bytes) within a BPF program that needs 191 * its insn->imm field to be relocated with actual field info; 192 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable 193 * field; 194 * - access_str_off - offset into corresponding .BTF string section. String 195 * itself encodes an accessed field using a sequence of field and array 196 * indicies, separated by colon (:). It's conceptually very close to LLVM's 197 * getelementptr ([0]) instruction's arguments for identifying offset to 198 * a field. 199 * 200 * Example to provide a better feel. 201 * 202 * struct sample { 203 * int a; 204 * struct { 205 * int b[10]; 206 * }; 207 * }; 208 * 209 * struct sample *s = ...; 210 * int x = &s->a; // encoded as "0:0" (a is field #0) 211 * int y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1, 212 * // b is field #0 inside anon struct, accessing elem #5) 213 * int z = &s[10]->b; // encoded as "10:1" (ptr is used as an array) 214 * 215 * type_id for all relocs in this example will capture BTF type id of 216 * `struct sample`. 217 * 218 * Such relocation is emitted when using __builtin_preserve_access_index() 219 * Clang built-in, passing expression that captures field address, e.g.: 220 * 221 * bpf_probe_read(&dst, sizeof(dst), 222 * __builtin_preserve_access_index(&src->a.b.c)); 223 * 224 * In this case Clang will emit field relocation recording necessary data to 225 * be able to find offset of embedded `a.b.c` field within `src` struct. 226 * 227 * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction 228 */ 229 struct bpf_field_reloc { 230 __u32 insn_off; 231 __u32 type_id; 232 __u32 access_str_off; 233 enum bpf_field_info_kind kind; 234 }; 235 236 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */ 237