1 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) 2 /* Copyright (c) 2018 Facebook */ 3 4 #include <string.h> 5 #include <stdlib.h> 6 #include <linux/err.h> 7 #include <linux/bpf.h> 8 #include "libbpf.h" 9 10 #ifndef min 11 #define min(x, y) ((x) < (y) ? (x) : (y)) 12 #endif 13 14 struct bpf_prog_linfo { 15 void *raw_linfo; 16 void *raw_jited_linfo; 17 __u32 *nr_jited_linfo_per_func; 18 __u32 *jited_linfo_func_idx; 19 __u32 nr_linfo; 20 __u32 nr_jited_func; 21 __u32 rec_size; 22 __u32 jited_rec_size; 23 }; 24 25 static int dissect_jited_func(struct bpf_prog_linfo *prog_linfo, 26 const __u64 *ksym_func, const __u32 *ksym_len) 27 { 28 __u32 nr_jited_func, nr_linfo; 29 const void *raw_jited_linfo; 30 const __u64 *jited_linfo; 31 __u64 last_jited_linfo; 32 /* 33 * Index to raw_jited_linfo: 34 * i: Index for searching the next ksym_func 35 * prev_i: Index to the last found ksym_func 36 */ 37 __u32 i, prev_i; 38 __u32 f; /* Index to ksym_func */ 39 40 raw_jited_linfo = prog_linfo->raw_jited_linfo; 41 jited_linfo = raw_jited_linfo; 42 if (ksym_func[0] != *jited_linfo) 43 goto errout; 44 45 prog_linfo->jited_linfo_func_idx[0] = 0; 46 nr_jited_func = prog_linfo->nr_jited_func; 47 nr_linfo = prog_linfo->nr_linfo; 48 49 for (prev_i = 0, i = 1, f = 1; 50 i < nr_linfo && f < nr_jited_func; 51 i++) { 52 raw_jited_linfo += prog_linfo->jited_rec_size; 53 last_jited_linfo = *jited_linfo; 54 jited_linfo = raw_jited_linfo; 55 56 if (ksym_func[f] == *jited_linfo) { 57 prog_linfo->jited_linfo_func_idx[f] = i; 58 59 /* Sanity check */ 60 if (last_jited_linfo - ksym_func[f - 1] + 1 > 61 ksym_len[f - 1]) 62 goto errout; 63 64 prog_linfo->nr_jited_linfo_per_func[f - 1] = 65 i - prev_i; 66 prev_i = i; 67 68 /* 69 * The ksym_func[f] is found in jited_linfo. 70 * Look for the next one. 71 */ 72 f++; 73 } else if (*jited_linfo <= last_jited_linfo) { 74 /* Ensure the addr is increasing _within_ a func */ 75 goto errout; 76 } 77 } 78 79 if (f != nr_jited_func) 80 goto errout; 81 82 prog_linfo->nr_jited_linfo_per_func[nr_jited_func - 1] = 83 nr_linfo - prev_i; 84 85 return 0; 86 87 errout: 88 return -EINVAL; 89 } 90 91 void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo) 92 { 93 if (!prog_linfo) 94 return; 95 96 free(prog_linfo->raw_linfo); 97 free(prog_linfo->raw_jited_linfo); 98 free(prog_linfo->nr_jited_linfo_per_func); 99 free(prog_linfo->jited_linfo_func_idx); 100 free(prog_linfo); 101 } 102 103 struct bpf_prog_linfo *bpf_prog_linfo__new(const struct bpf_prog_info *info) 104 { 105 struct bpf_prog_linfo *prog_linfo; 106 __u32 nr_linfo, nr_jited_func; 107 108 nr_linfo = info->nr_line_info; 109 110 if (!nr_linfo) 111 return NULL; 112 113 /* 114 * The min size that bpf_prog_linfo has to access for 115 * searching purpose. 116 */ 117 if (info->line_info_rec_size < 118 offsetof(struct bpf_line_info, file_name_off)) 119 return NULL; 120 121 prog_linfo = calloc(1, sizeof(*prog_linfo)); 122 if (!prog_linfo) 123 return NULL; 124 125 /* Copy xlated line_info */ 126 prog_linfo->nr_linfo = nr_linfo; 127 prog_linfo->rec_size = info->line_info_rec_size; 128 prog_linfo->raw_linfo = malloc(nr_linfo * prog_linfo->rec_size); 129 if (!prog_linfo->raw_linfo) 130 goto err_free; 131 memcpy(prog_linfo->raw_linfo, (void *)(long)info->line_info, 132 nr_linfo * prog_linfo->rec_size); 133 134 nr_jited_func = info->nr_jited_ksyms; 135 if (!nr_jited_func || 136 !info->jited_line_info || 137 info->nr_jited_line_info != nr_linfo || 138 info->jited_line_info_rec_size < sizeof(__u64) || 139 info->nr_jited_func_lens != nr_jited_func || 140 !info->jited_ksyms || 141 !info->jited_func_lens) 142 /* Not enough info to provide jited_line_info */ 143 return prog_linfo; 144 145 /* Copy jited_line_info */ 146 prog_linfo->nr_jited_func = nr_jited_func; 147 prog_linfo->jited_rec_size = info->jited_line_info_rec_size; 148 prog_linfo->raw_jited_linfo = malloc(nr_linfo * 149 prog_linfo->jited_rec_size); 150 if (!prog_linfo->raw_jited_linfo) 151 goto err_free; 152 memcpy(prog_linfo->raw_jited_linfo, 153 (void *)(long)info->jited_line_info, 154 nr_linfo * prog_linfo->jited_rec_size); 155 156 /* Number of jited_line_info per jited func */ 157 prog_linfo->nr_jited_linfo_per_func = malloc(nr_jited_func * 158 sizeof(__u32)); 159 if (!prog_linfo->nr_jited_linfo_per_func) 160 goto err_free; 161 162 /* 163 * For each jited func, 164 * the start idx to the "linfo" and "jited_linfo" array, 165 */ 166 prog_linfo->jited_linfo_func_idx = malloc(nr_jited_func * 167 sizeof(__u32)); 168 if (!prog_linfo->jited_linfo_func_idx) 169 goto err_free; 170 171 if (dissect_jited_func(prog_linfo, 172 (__u64 *)(long)info->jited_ksyms, 173 (__u32 *)(long)info->jited_func_lens)) 174 goto err_free; 175 176 return prog_linfo; 177 178 err_free: 179 bpf_prog_linfo__free(prog_linfo); 180 return NULL; 181 } 182 183 const struct bpf_line_info * 184 bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo, 185 __u64 addr, __u32 func_idx, __u32 nr_skip) 186 { 187 __u32 jited_rec_size, rec_size, nr_linfo, start, i; 188 const void *raw_jited_linfo, *raw_linfo; 189 const __u64 *jited_linfo; 190 191 if (func_idx >= prog_linfo->nr_jited_func) 192 return NULL; 193 194 nr_linfo = prog_linfo->nr_jited_linfo_per_func[func_idx]; 195 if (nr_skip >= nr_linfo) 196 return NULL; 197 198 start = prog_linfo->jited_linfo_func_idx[func_idx] + nr_skip; 199 jited_rec_size = prog_linfo->jited_rec_size; 200 raw_jited_linfo = prog_linfo->raw_jited_linfo + 201 (start * jited_rec_size); 202 jited_linfo = raw_jited_linfo; 203 if (addr < *jited_linfo) 204 return NULL; 205 206 nr_linfo -= nr_skip; 207 rec_size = prog_linfo->rec_size; 208 raw_linfo = prog_linfo->raw_linfo + (start * rec_size); 209 for (i = 0; i < nr_linfo; i++) { 210 if (addr < *jited_linfo) 211 break; 212 213 raw_linfo += rec_size; 214 raw_jited_linfo += jited_rec_size; 215 jited_linfo = raw_jited_linfo; 216 } 217 218 return raw_linfo - rec_size; 219 } 220 221 const struct bpf_line_info * 222 bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo, 223 __u32 insn_off, __u32 nr_skip) 224 { 225 const struct bpf_line_info *linfo; 226 __u32 rec_size, nr_linfo, i; 227 const void *raw_linfo; 228 229 nr_linfo = prog_linfo->nr_linfo; 230 if (nr_skip >= nr_linfo) 231 return NULL; 232 233 rec_size = prog_linfo->rec_size; 234 raw_linfo = prog_linfo->raw_linfo + (nr_skip * rec_size); 235 linfo = raw_linfo; 236 if (insn_off < linfo->insn_off) 237 return NULL; 238 239 nr_linfo -= nr_skip; 240 for (i = 0; i < nr_linfo; i++) { 241 if (insn_off < linfo->insn_off) 242 break; 243 244 raw_linfo += rec_size; 245 linfo = raw_linfo; 246 } 247 248 return raw_linfo - rec_size; 249 } 250