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linux/tools/bpf/bpftool/btf_dumper.c
Yonghong Song 298e59d322 tools/bpf: fix bpftool map dump with bitfields 
Commit 8772c8bc09 ("tools: bpftool: support pretty print
with kind_flag set") added bpftool map dump with kind_flag
support. When bitfield_size can be retrieved directly from
btf_member, function btf_dumper_bitfield() is called to
dump the bitfield. The implementation passed the
wrong parameter "bit_offset" to the function. The excepted
value is the bit_offset within a byte while the passed-in
value is the struct member offset.

This commit fixed the bug with passing correct "bit_offset"
with adjusted data pointer.

Fixes: 8772c8bc09 ("tools: bpftool: support pretty print with kind_flag set")
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-11 10:40:54 +01:00

483 lines
12 KiB
C
Raw Blame History

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */
#include <ctype.h>
#include <stdio.h> /* for (FILE *) used by json_writer */
#include <string.h>
#include <asm/byteorder.h>
#include <linux/bitops.h>
#include <linux/btf.h>
#include <linux/err.h>
#include "btf.h"
#include "json_writer.h"
#include "main.h"
#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
#define BITS_ROUNDUP_BYTES(bits) \
(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
__u8 bit_offset, const void *data);
static void btf_dumper_ptr(const void *data, json_writer_t *jw,
bool is_plain_text)
{
if (is_plain_text)
jsonw_printf(jw, "%p", *(unsigned long *)data);
else
jsonw_printf(jw, "%u", *(unsigned long *)data);
}
static int btf_dumper_modifier(const struct btf_dumper *d, __u32 type_id,
__u8 bit_offset, const void *data)
{
int actual_type_id;
actual_type_id = btf__resolve_type(d->btf, type_id);
if (actual_type_id < 0)
return actual_type_id;
return btf_dumper_do_type(d, actual_type_id, bit_offset, data);
}
static void btf_dumper_enum(const void *data, json_writer_t *jw)
{
jsonw_printf(jw, "%d", *(int *)data);
}
static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
const void *data)
{
const struct btf_type *t = btf__type_by_id(d->btf, type_id);
struct btf_array *arr = (struct btf_array *)(t + 1);
long long elem_size;
int ret = 0;
__u32 i;
elem_size = btf__resolve_size(d->btf, arr->type);
if (elem_size < 0)
return elem_size;
jsonw_start_array(d->jw);
for (i = 0; i < arr->nelems; i++) {
ret = btf_dumper_do_type(d, arr->type, 0,
data + i * elem_size);
if (ret)
break;
}
jsonw_end_array(d->jw);
return ret;
}
static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
const void *data, json_writer_t *jw,
bool is_plain_text)
{
int left_shift_bits, right_shift_bits;
int bytes_to_copy;
int bits_to_copy;
__u64 print_num;
bits_to_copy = bit_offset + nr_bits;
bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);
print_num = 0;
memcpy(&print_num, data, bytes_to_copy);
#if defined(__BIG_ENDIAN_BITFIELD)
left_shift_bits = bit_offset;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
left_shift_bits = 64 - bits_to_copy;
#else
#error neither big nor little endian
#endif
right_shift_bits = 64 - nr_bits;
print_num <<= left_shift_bits;
print_num >>= right_shift_bits;
if (is_plain_text)
jsonw_printf(jw, "0x%llx", print_num);
else
jsonw_printf(jw, "%llu", print_num);
}
static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
const void *data, json_writer_t *jw,
bool is_plain_text)
{
int nr_bits = BTF_INT_BITS(int_type);
int total_bits_offset;
/* bits_offset is at most 7.
* BTF_INT_OFFSET() cannot exceed 64 bits.
*/
total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
btf_dumper_bitfield(nr_bits, bit_offset, data, jw,
is_plain_text);
}
static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
const void *data, json_writer_t *jw,
bool is_plain_text)
{
__u32 *int_type;
__u32 nr_bits;
int_type = (__u32 *)(t + 1);
nr_bits = BTF_INT_BITS(*int_type);
/* if this is bit field */
if (bit_offset || BTF_INT_OFFSET(*int_type) ||
BITS_PER_BYTE_MASKED(nr_bits)) {
btf_dumper_int_bits(*int_type, bit_offset, data, jw,
is_plain_text);
return 0;
}
switch (BTF_INT_ENCODING(*int_type)) {
case 0:
if (BTF_INT_BITS(*int_type) == 64)
jsonw_printf(jw, "%lu", *(__u64 *)data);
else if (BTF_INT_BITS(*int_type) == 32)
jsonw_printf(jw, "%u", *(__u32 *)data);
else if (BTF_INT_BITS(*int_type) == 16)
jsonw_printf(jw, "%hu", *(__u16 *)data);
else if (BTF_INT_BITS(*int_type) == 8)
jsonw_printf(jw, "%hhu", *(__u8 *)data);
else
btf_dumper_int_bits(*int_type, bit_offset, data, jw,
is_plain_text);
break;
case BTF_INT_SIGNED:
if (BTF_INT_BITS(*int_type) == 64)
jsonw_printf(jw, "%ld", *(long long *)data);
else if (BTF_INT_BITS(*int_type) == 32)
jsonw_printf(jw, "%d", *(int *)data);
else if (BTF_INT_BITS(*int_type) == 16)
jsonw_printf(jw, "%hd", *(short *)data);
else if (BTF_INT_BITS(*int_type) == 8)
jsonw_printf(jw, "%hhd", *(char *)data);
else
btf_dumper_int_bits(*int_type, bit_offset, data, jw,
is_plain_text);
break;
case BTF_INT_CHAR:
if (isprint(*(char *)data))
jsonw_printf(jw, "\"%c\"", *(char *)data);
else
if (is_plain_text)
jsonw_printf(jw, "0x%hhx", *(char *)data);
else
jsonw_printf(jw, "\"\\u00%02hhx\"",
*(char *)data);
break;
case BTF_INT_BOOL:
jsonw_bool(jw, *(int *)data);
break;
default:
/* shouldn't happen */
return -EINVAL;
}
return 0;
}
static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
const void *data)
{
const struct btf_type *t;
struct btf_member *m;
const void *data_off;
int kind_flag;
int ret = 0;
int i, vlen;
t = btf__type_by_id(d->btf, type_id);
if (!t)
return -EINVAL;
kind_flag = BTF_INFO_KFLAG(t->info);
vlen = BTF_INFO_VLEN(t->info);
jsonw_start_object(d->jw);
m = (struct btf_member *)(t + 1);
for (i = 0; i < vlen; i++) {
__u32 bit_offset = m[i].offset;
__u32 bitfield_size = 0;
if (kind_flag) {
bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
}
jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
if (bitfield_size) {
btf_dumper_bitfield(bitfield_size,
BITS_PER_BYTE_MASKED(bit_offset),
data_off, d->jw, d->is_plain_text);
} else {
ret = btf_dumper_do_type(d, m[i].type,
BITS_PER_BYTE_MASKED(bit_offset),
data_off);
if (ret)
break;
}
}
jsonw_end_object(d->jw);
return ret;
}
static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
__u8 bit_offset, const void *data)
{
const struct btf_type *t = btf__type_by_id(d->btf, type_id);
switch (BTF_INFO_KIND(t->info)) {
case BTF_KIND_INT:
return btf_dumper_int(t, bit_offset, data, d->jw,
d->is_plain_text);
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
return btf_dumper_struct(d, type_id, data);
case BTF_KIND_ARRAY:
return btf_dumper_array(d, type_id, data);
case BTF_KIND_ENUM:
btf_dumper_enum(data, d->jw);
return 0;
case BTF_KIND_PTR:
btf_dumper_ptr(data, d->jw, d->is_plain_text);
return 0;
case BTF_KIND_UNKN:
jsonw_printf(d->jw, "(unknown)");
return 0;
case BTF_KIND_FWD:
/* map key or value can't be forward */
jsonw_printf(d->jw, "(fwd-kind-invalid)");
return -EINVAL;
case BTF_KIND_TYPEDEF:
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
return btf_dumper_modifier(d, type_id, bit_offset, data);
default:
jsonw_printf(d->jw, "(unsupported-kind");
return -EINVAL;
}
}
int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
const void *data)
{
return btf_dumper_do_type(d, type_id, 0, data);
}
#define BTF_PRINT_ARG(...) \
do { \
pos += snprintf(func_sig + pos, size - pos, \
__VA_ARGS__); \
if (pos >= size) \
return -1; \
} while (0)
#define BTF_PRINT_TYPE(type) \
do { \
pos = __btf_dumper_type_only(btf, type, func_sig, \
pos, size); \
if (pos == -1) \
return -1; \
} while (0)
static int btf_dump_func(const struct btf *btf, char *func_sig,
const struct btf_type *func_proto,
const struct btf_type *func, int pos, int size);
static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
char *func_sig, int pos, int size)
{
const struct btf_type *proto_type;
const struct btf_array *array;
const struct btf_type *t;
if (!type_id) {
BTF_PRINT_ARG("void ");
return pos;
}
t = btf__type_by_id(btf, type_id);
switch (BTF_INFO_KIND(t->info)) {
case BTF_KIND_INT:
case BTF_KIND_TYPEDEF:
BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_STRUCT:
BTF_PRINT_ARG("struct %s ",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_UNION:
BTF_PRINT_ARG("union %s ",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_ENUM:
BTF_PRINT_ARG("enum %s ",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_ARRAY:
array = (struct btf_array *)(t + 1);
BTF_PRINT_TYPE(array->type);
BTF_PRINT_ARG("[%d]", array->nelems);
break;
case BTF_KIND_PTR:
BTF_PRINT_TYPE(t->type);
BTF_PRINT_ARG("* ");
break;
case BTF_KIND_FWD:
BTF_PRINT_ARG("%s %s ",
BTF_INFO_KFLAG(t->info) ? "union" : "struct",
btf__name_by_offset(btf, t->name_off));
break;
case BTF_KIND_VOLATILE:
BTF_PRINT_ARG("volatile ");
BTF_PRINT_TYPE(t->type);
break;
case BTF_KIND_CONST:
BTF_PRINT_ARG("const ");
BTF_PRINT_TYPE(t->type);
break;
case BTF_KIND_RESTRICT:
BTF_PRINT_ARG("restrict ");
BTF_PRINT_TYPE(t->type);
break;
case BTF_KIND_FUNC_PROTO:
pos = btf_dump_func(btf, func_sig, t, NULL, pos, size);
if (pos == -1)
return -1;
break;
case BTF_KIND_FUNC:
proto_type = btf__type_by_id(btf, t->type);
pos = btf_dump_func(btf, func_sig, proto_type, t, pos, size);
if (pos == -1)
return -1;
break;
case BTF_KIND_UNKN:
default:
return -1;
}
return pos;
}
static int btf_dump_func(const struct btf *btf, char *func_sig,
const struct btf_type *func_proto,
const struct btf_type *func, int pos, int size)
{
int i, vlen;
BTF_PRINT_TYPE(func_proto->type);
if (func)
BTF_PRINT_ARG("%s(", btf__name_by_offset(btf, func->name_off));
else
BTF_PRINT_ARG("(");
vlen = BTF_INFO_VLEN(func_proto->info);
for (i = 0; i < vlen; i++) {
struct btf_param *arg = &((struct btf_param *)(func_proto + 1))[i];
if (i)
BTF_PRINT_ARG(", ");
if (arg->type) {
BTF_PRINT_TYPE(arg->type);
BTF_PRINT_ARG("%s",
btf__name_by_offset(btf, arg->name_off));
} else {
BTF_PRINT_ARG("...");
}
}
BTF_PRINT_ARG(")");
return pos;
}
void btf_dumper_type_only(const struct btf *btf, __u32 type_id, char *func_sig,
int size)
{
int err;
func_sig[0] = '\0';
if (!btf)
return;
err = __btf_dumper_type_only(btf, type_id, func_sig, 0, size);
if (err < 0)
func_sig[0] = '\0';
}
static const char *ltrim(const char *s)
{
while (isspace(*s))
s++;
return s;
}
void btf_dump_linfo_plain(const struct btf *btf,
const struct bpf_line_info *linfo,
const char *prefix, bool linum)
{
const char *line = btf__name_by_offset(btf, linfo->line_off);
if (!line)
return;
line = ltrim(line);
if (!prefix)
prefix = "";
if (linum) {
const char *file = btf__name_by_offset(btf, linfo->file_name_off);
/* More forgiving on file because linum option is
* expected to provide more info than the already
* available src line.
*/
if (!file)
file = "";
printf("%s%s [file:%s line_num:%u line_col:%u]\n",
prefix, line, file,
BPF_LINE_INFO_LINE_NUM(linfo->line_col),
BPF_LINE_INFO_LINE_COL(linfo->line_col));
} else {
printf("%s%s\n", prefix, line);
}
}
void btf_dump_linfo_json(const struct btf *btf,
const struct bpf_line_info *linfo, bool linum)
{
const char *line = btf__name_by_offset(btf, linfo->line_off);
if (line)
jsonw_string_field(json_wtr, "src", ltrim(line));
if (linum) {
const char *file = btf__name_by_offset(btf, linfo->file_name_off);
if (file)
jsonw_string_field(json_wtr, "file", file);
if (BPF_LINE_INFO_LINE_NUM(linfo->line_col))
jsonw_int_field(json_wtr, "line_num",
BPF_LINE_INFO_LINE_NUM(linfo->line_col));
if (BPF_LINE_INFO_LINE_COL(linfo->line_col))
jsonw_int_field(json_wtr, "line_col",
BPF_LINE_INFO_LINE_COL(linfo->line_col));
}
}
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