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 /* 111 * Test !info->line_info because the kernel may NULL 112 * the ptr if kernel.kptr_restrict is set. 113 */ 114 if (!nr_linfo || !info->line_info) 115 return NULL; 116 117 /* 118 * The min size that bpf_prog_linfo has to access for 119 * searching purpose. 120 */ 121 if (info->line_info_rec_size < 122 offsetof(struct bpf_line_info, file_name_off)) 123 return NULL; 124 125 prog_linfo = calloc(1, sizeof(*prog_linfo)); 126 if (!prog_linfo) 127 return NULL; 128 129 /* Copy xlated line_info */ 130 prog_linfo->nr_linfo = nr_linfo; 131 prog_linfo->rec_size = info->line_info_rec_size; 132 prog_linfo->raw_linfo = malloc(nr_linfo * prog_linfo->rec_size); 133 if (!prog_linfo->raw_linfo) 134 goto err_free; 135 memcpy(prog_linfo->raw_linfo, (void *)(long)info->line_info, 136 nr_linfo * prog_linfo->rec_size); 137 138 nr_jited_func = info->nr_jited_ksyms; 139 if (!nr_jited_func || 140 !info->jited_line_info || 141 info->nr_jited_line_info != nr_linfo || 142 info->jited_line_info_rec_size < sizeof(__u64) || 143 info->nr_jited_func_lens != nr_jited_func || 144 !info->jited_ksyms || 145 !info->jited_func_lens) 146 /* Not enough info to provide jited_line_info */ 147 return prog_linfo; 148 149 /* Copy jited_line_info */ 150 prog_linfo->nr_jited_func = nr_jited_func; 151 prog_linfo->jited_rec_size = info->jited_line_info_rec_size; 152 prog_linfo->raw_jited_linfo = malloc(nr_linfo * 153 prog_linfo->jited_rec_size); 154 if (!prog_linfo->raw_jited_linfo) 155 goto err_free; 156 memcpy(prog_linfo->raw_jited_linfo, 157 (void *)(long)info->jited_line_info, 158 nr_linfo * prog_linfo->jited_rec_size); 159 160 /* Number of jited_line_info per jited func */ 161 prog_linfo->nr_jited_linfo_per_func = malloc(nr_jited_func * 162 sizeof(__u32)); 163 if (!prog_linfo->nr_jited_linfo_per_func) 164 goto err_free; 165 166 /* 167 * For each jited func, 168 * the start idx to the "linfo" and "jited_linfo" array, 169 */ 170 prog_linfo->jited_linfo_func_idx = malloc(nr_jited_func * 171 sizeof(__u32)); 172 if (!prog_linfo->jited_linfo_func_idx) 173 goto err_free; 174 175 if (dissect_jited_func(prog_linfo, 176 (__u64 *)(long)info->jited_ksyms, 177 (__u32 *)(long)info->jited_func_lens)) 178 goto err_free; 179 180 return prog_linfo; 181 182 err_free: 183 bpf_prog_linfo__free(prog_linfo); 184 return NULL; 185 } 186 187 const struct bpf_line_info * 188 bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo, 189 __u64 addr, __u32 func_idx, __u32 nr_skip) 190 { 191 __u32 jited_rec_size, rec_size, nr_linfo, start, i; 192 const void *raw_jited_linfo, *raw_linfo; 193 const __u64 *jited_linfo; 194 195 if (func_idx >= prog_linfo->nr_jited_func) 196 return NULL; 197 198 nr_linfo = prog_linfo->nr_jited_linfo_per_func[func_idx]; 199 if (nr_skip >= nr_linfo) 200 return NULL; 201 202 start = prog_linfo->jited_linfo_func_idx[func_idx] + nr_skip; 203 jited_rec_size = prog_linfo->jited_rec_size; 204 raw_jited_linfo = prog_linfo->raw_jited_linfo + 205 (start * jited_rec_size); 206 jited_linfo = raw_jited_linfo; 207 if (addr < *jited_linfo) 208 return NULL; 209 210 nr_linfo -= nr_skip; 211 rec_size = prog_linfo->rec_size; 212 raw_linfo = prog_linfo->raw_linfo + (start * rec_size); 213 for (i = 0; i < nr_linfo; i++) { 214 if (addr < *jited_linfo) 215 break; 216 217 raw_linfo += rec_size; 218 raw_jited_linfo += jited_rec_size; 219 jited_linfo = raw_jited_linfo; 220 } 221 222 return raw_linfo - rec_size; 223 } 224 225 const struct bpf_line_info * 226 bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo, 227 __u32 insn_off, __u32 nr_skip) 228 { 229 const struct bpf_line_info *linfo; 230 __u32 rec_size, nr_linfo, i; 231 const void *raw_linfo; 232 233 nr_linfo = prog_linfo->nr_linfo; 234 if (nr_skip >= nr_linfo) 235 return NULL; 236 237 rec_size = prog_linfo->rec_size; 238 raw_linfo = prog_linfo->raw_linfo + (nr_skip * rec_size); 239 linfo = raw_linfo; 240 if (insn_off < linfo->insn_off) 241 return NULL; 242 243 nr_linfo -= nr_skip; 244 for (i = 0; i < nr_linfo; i++) { 245 if (insn_off < linfo->insn_off) 246 break; 247 248 raw_linfo += rec_size; 249 linfo = raw_linfo; 250 } 251 252 return raw_linfo - rec_size; 253 } 254