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/* make sure libbpf doesn't use kernel-only integer typedefs */
 12#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
 13
 14struct 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
 25static 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
 87errout:
 88	return -EINVAL;
 89}
 90
 91void 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
103struct 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	__u64 data_sz;
108
109	nr_linfo = info->nr_line_info;
110
111	if (!nr_linfo)
112		return NULL;
113
114	/*
115	 * The min size that bpf_prog_linfo has to access for
116	 * searching purpose.
117	 */
118	if (info->line_info_rec_size <
119	    offsetof(struct bpf_line_info, file_name_off))
120		return NULL;
121
122	prog_linfo = calloc(1, sizeof(*prog_linfo));
123	if (!prog_linfo)
124		return NULL;
125
126	/* Copy xlated line_info */
127	prog_linfo->nr_linfo = nr_linfo;
128	prog_linfo->rec_size = info->line_info_rec_size;
129	data_sz = (__u64)nr_linfo * prog_linfo->rec_size;
130	prog_linfo->raw_linfo = malloc(data_sz);
131	if (!prog_linfo->raw_linfo)
132		goto err_free;
133	memcpy(prog_linfo->raw_linfo, (void *)(long)info->line_info, data_sz);
134
135	nr_jited_func = info->nr_jited_ksyms;
136	if (!nr_jited_func ||
137	    !info->jited_line_info ||
138	    info->nr_jited_line_info != nr_linfo ||
139	    info->jited_line_info_rec_size < sizeof(__u64) ||
140	    info->nr_jited_func_lens != nr_jited_func ||
141	    !info->jited_ksyms ||
142	    !info->jited_func_lens)
143		/* Not enough info to provide jited_line_info */
144		return prog_linfo;
145
146	/* Copy jited_line_info */
147	prog_linfo->nr_jited_func = nr_jited_func;
148	prog_linfo->jited_rec_size = info->jited_line_info_rec_size;
149	data_sz = (__u64)nr_linfo * prog_linfo->jited_rec_size;
150	prog_linfo->raw_jited_linfo = malloc(data_sz);
151	if (!prog_linfo->raw_jited_linfo)
152		goto err_free;
153	memcpy(prog_linfo->raw_jited_linfo,
154	       (void *)(long)info->jited_line_info, data_sz);
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
178err_free:
179	bpf_prog_linfo__free(prog_linfo);
180	return NULL;
181}
182
183const struct bpf_line_info *
184bpf_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
221const struct bpf_line_info *
222bpf_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}