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