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// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */
#include <string.h>
#include <stdlib.h>
#include <linux/err.h>
#include <linux/bpf.h>
#include "libbpf.h"
#ifndef min
#define min(x, y) ((x) < (y) ? (x) : (y))
#endif
struct bpf_prog_linfo {
void *raw_linfo;
void *raw_jited_linfo;
__u32 *nr_jited_linfo_per_func;
__u32 *jited_linfo_func_idx;
__u32 nr_linfo;
__u32 nr_jited_func;
__u32 rec_size;
__u32 jited_rec_size;
};
static int dissect_jited_func(struct bpf_prog_linfo *prog_linfo,
const __u64 *ksym_func, const __u32 *ksym_len)
{
__u32 nr_jited_func, nr_linfo;
const void *raw_jited_linfo;
const __u64 *jited_linfo;
__u64 last_jited_linfo;
/*
* Index to raw_jited_linfo:
* i: Index for searching the next ksym_func
* prev_i: Index to the last found ksym_func
*/
__u32 i, prev_i;
__u32 f; /* Index to ksym_func */
raw_jited_linfo = prog_linfo->raw_jited_linfo;
jited_linfo = raw_jited_linfo;
if (ksym_func[0] != *jited_linfo)
goto errout;
prog_linfo->jited_linfo_func_idx[0] = 0;
nr_jited_func = prog_linfo->nr_jited_func;
nr_linfo = prog_linfo->nr_linfo;
for (prev_i = 0, i = 1, f = 1;
i < nr_linfo && f < nr_jited_func;
i++) {
raw_jited_linfo += prog_linfo->jited_rec_size;
last_jited_linfo = *jited_linfo;
jited_linfo = raw_jited_linfo;
if (ksym_func[f] == *jited_linfo) {
prog_linfo->jited_linfo_func_idx[f] = i;
/* Sanity check */
if (last_jited_linfo - ksym_func[f - 1] + 1 >
ksym_len[f - 1])
goto errout;
prog_linfo->nr_jited_linfo_per_func[f - 1] =
i - prev_i;
prev_i = i;
/*
* The ksym_func[f] is found in jited_linfo.
* Look for the next one.
*/
f++;
} else if (*jited_linfo <= last_jited_linfo) {
/* Ensure the addr is increasing _within_ a func */
goto errout;
}
}
if (f != nr_jited_func)
goto errout;
prog_linfo->nr_jited_linfo_per_func[nr_jited_func - 1] =
nr_linfo - prev_i;
return 0;
errout:
return -EINVAL;
}
void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo)
{
if (!prog_linfo)
return;
free(prog_linfo->raw_linfo);
free(prog_linfo->raw_jited_linfo);
free(prog_linfo->nr_jited_linfo_per_func);
free(prog_linfo->jited_linfo_func_idx);
free(prog_linfo);
}
struct bpf_prog_linfo *bpf_prog_linfo__new(const struct bpf_prog_info *info)
{
struct bpf_prog_linfo *prog_linfo;
__u32 nr_linfo, nr_jited_func;
nr_linfo = info->nr_line_info;
/*
* Test !info->line_info because the kernel may NULL
* the ptr if kernel.kptr_restrict is set.
*/
if (!nr_linfo || !info->line_info)
return NULL;
/*
* The min size that bpf_prog_linfo has to access for
* searching purpose.
*/
if (info->line_info_rec_size <
offsetof(struct bpf_line_info, file_name_off))
return NULL;
prog_linfo = calloc(1, sizeof(*prog_linfo));
if (!prog_linfo)
return NULL;
/* Copy xlated line_info */
prog_linfo->nr_linfo = nr_linfo;
prog_linfo->rec_size = info->line_info_rec_size;
prog_linfo->raw_linfo = malloc(nr_linfo * prog_linfo->rec_size);
if (!prog_linfo->raw_linfo)
goto err_free;
memcpy(prog_linfo->raw_linfo, (void *)(long)info->line_info,
nr_linfo * prog_linfo->rec_size);
nr_jited_func = info->nr_jited_ksyms;
if (!nr_jited_func ||
!info->jited_line_info ||
info->nr_jited_line_info != nr_linfo ||
info->jited_line_info_rec_size < sizeof(__u64) ||
info->nr_jited_func_lens != nr_jited_func ||
!info->jited_ksyms ||
!info->jited_func_lens)
/* Not enough info to provide jited_line_info */
return prog_linfo;
/* Copy jited_line_info */
prog_linfo->nr_jited_func = nr_jited_func;
prog_linfo->jited_rec_size = info->jited_line_info_rec_size;
prog_linfo->raw_jited_linfo = malloc(nr_linfo *
prog_linfo->jited_rec_size);
if (!prog_linfo->raw_jited_linfo)
goto err_free;
memcpy(prog_linfo->raw_jited_linfo,
(void *)(long)info->jited_line_info,
nr_linfo * prog_linfo->jited_rec_size);
/* Number of jited_line_info per jited func */
prog_linfo->nr_jited_linfo_per_func = malloc(nr_jited_func *
sizeof(__u32));
if (!prog_linfo->nr_jited_linfo_per_func)
goto err_free;
/*
* For each jited func,
* the start idx to the "linfo" and "jited_linfo" array,
*/
prog_linfo->jited_linfo_func_idx = malloc(nr_jited_func *
sizeof(__u32));
if (!prog_linfo->jited_linfo_func_idx)
goto err_free;
if (dissect_jited_func(prog_linfo,
(__u64 *)(long)info->jited_ksyms,
(__u32 *)(long)info->jited_func_lens))
goto err_free;
return prog_linfo;
err_free:
bpf_prog_linfo__free(prog_linfo);
return NULL;
}
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)
{
__u32 jited_rec_size, rec_size, nr_linfo, start, i;
const void *raw_jited_linfo, *raw_linfo;
const __u64 *jited_linfo;
if (func_idx >= prog_linfo->nr_jited_func)
return NULL;
nr_linfo = prog_linfo->nr_jited_linfo_per_func[func_idx];
if (nr_skip >= nr_linfo)
return NULL;
start = prog_linfo->jited_linfo_func_idx[func_idx] + nr_skip;
jited_rec_size = prog_linfo->jited_rec_size;
raw_jited_linfo = prog_linfo->raw_jited_linfo +
(start * jited_rec_size);
jited_linfo = raw_jited_linfo;
if (addr < *jited_linfo)
return NULL;
nr_linfo -= nr_skip;
rec_size = prog_linfo->rec_size;
raw_linfo = prog_linfo->raw_linfo + (start * rec_size);
for (i = 0; i < nr_linfo; i++) {
if (addr < *jited_linfo)
break;
raw_linfo += rec_size;
raw_jited_linfo += jited_rec_size;
jited_linfo = raw_jited_linfo;
}
return raw_linfo - rec_size;
}
const struct bpf_line_info *
bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo,
__u32 insn_off, __u32 nr_skip)
{
const struct bpf_line_info *linfo;
__u32 rec_size, nr_linfo, i;
const void *raw_linfo;
nr_linfo = prog_linfo->nr_linfo;
if (nr_skip >= nr_linfo)
return NULL;
rec_size = prog_linfo->rec_size;
raw_linfo = prog_linfo->raw_linfo + (nr_skip * rec_size);
linfo = raw_linfo;
if (insn_off < linfo->insn_off)
return NULL;
nr_linfo -= nr_skip;
for (i = 0; i < nr_linfo; i++) {
if (insn_off < linfo->insn_off)
break;
raw_linfo += rec_size;
linfo = raw_linfo;
}
return raw_linfo - rec_size;
}
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