[PATCH v2 bpf-next 3/4] libbpf: BTF dumper support for typed data
From: Alan Maguire
Date: Sun Jan 17 2021 - 17:25:38 EST
Add a BTF dumper for typed data, so that the user can dump a typed
version of the data provided.
The API is
int btf_dump__emit_type_data(struct btf_dump *d, __u32 id,
const struct btf_dump_emit_type_data_opts *opts,
void *data);
...where the id is the BTF id of the data pointed to by the "void *"
argument; for example the BTF id of "struct sk_buff" for a
"struct skb *" data pointer. Options supported are
- a starting indent level (indent_lvl)
- a set of boolean options to control dump display, similar to those
used for BPF helper bpf_snprintf_btf(). Options are
- compact : omit newlines and other indentation
- noname: omit member names
- zero: show zero-value members
Default output format is identical to that dumped by bpf_snprintf_btf(),
for example a "struct sk_buff" representation would look like this:
struct sk_buff){
(union){
(struct){
.next = (struct sk_buff *)0xffffffffffffffff,
.prev = (struct sk_buff *)0xffffffffffffffff,
(union){
.dev = (struct net_device *)0xffffffffffffffff,
.dev_scratch = (long unsigned int)18446744073709551615,
},
},
...
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
tools/lib/bpf/btf.h | 17 +
tools/lib/bpf/btf_dump.c | 974 +++++++++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.map | 5 +
3 files changed, 996 insertions(+)
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 0c48f2e..7937124 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -180,6 +180,23 @@ struct btf_dump_emit_type_decl_opts {
btf_dump__emit_type_decl(struct btf_dump *d, __u32 id,
const struct btf_dump_emit_type_decl_opts *opts);
+
+struct btf_dump_emit_type_data_opts {
+ /* size of this struct, for forward/backward compatibility */
+ size_t sz;
+ int indent_level;
+ /* below match "show" flags for bpf_show_snprintf() */
+ bool compact;
+ bool noname;
+ bool zero;
+};
+#define btf_dump_emit_type_data_opts__last_field zero
+
+LIBBPF_API int
+btf_dump__emit_type_data(struct btf_dump *d, __u32 id,
+ const struct btf_dump_emit_type_data_opts *opts,
+ void *data);
+
/*
* A set of helpers for easier BTF types handling
*/
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 2f9d685..04d604f 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -10,6 +10,8 @@
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
+#include <ctype.h>
+#include <endian.h>
#include <errno.h>
#include <linux/err.h>
#include <linux/btf.h>
@@ -19,14 +21,31 @@
#include "libbpf.h"
#include "libbpf_internal.h"
+#define BITS_PER_BYTE 8
+#define BITS_PER_U128 (sizeof(__u64) * BITS_PER_BYTE * 2)
+#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 const char PREFIXES[] = "\t\t\t\t\t\t\t\t\t\t\t\t\t";
static const size_t PREFIX_CNT = sizeof(PREFIXES) - 1;
+
static const char *pfx(int lvl)
{
return lvl >= PREFIX_CNT ? PREFIXES : &PREFIXES[PREFIX_CNT - lvl];
}
+static const char SPREFIXES[] = " ";
+static const size_t SPREFIX_CNT = sizeof(SPREFIXES) - 1;
+
+static const char *spfx(int lvl)
+{
+ return lvl >= SPREFIX_CNT ? SPREFIXES : &SPREFIXES[SPREFIX_CNT - lvl];
+}
+
enum btf_dump_type_order_state {
NOT_ORDERED,
ORDERING,
@@ -53,6 +72,49 @@ struct btf_dump_type_aux_state {
__u8 referenced: 1;
};
+#define BTF_DUMP_DATA_MAX_NAME_LEN 256
+
+/*
+ * Common internal data for BTF type data dump operations.
+ *
+ * The implementation here is similar to that in kernel/bpf/btf.c
+ * that supports the bpf_snprintf_btf() helper, so any bugs in
+ * type data dumping here are likely in that code also.
+ *
+ * One challenge with showing nested data is we want to skip 0-valued
+ * data, but in order to figure out whether a nested object is all zeros
+ * we need to walk through it. As a result, we need to make two passes
+ * when handling structs, unions and arrays; the first path simply looks
+ * for nonzero data, while the second actually does the display. The first
+ * pass is signalled by state.depth_check being set, and if we
+ * encounter a non-zero value we set state.depth_to_show to the depth
+ * at which we encountered it. When we have completed the first pass,
+ * we will know if anything needs to be displayed if
+ * state.depth_to_show > state.depth. See btf_dump_emit_[struct,array]_data()
+ * for the implementation of this.
+ *
+ */
+struct btf_dump_data {
+ bool compact;
+ bool noname;
+ bool zero;
+ __u8 indent_lvl; /* base indent level */
+ /* below are used during iteration */
+ struct {
+ __u8 depth;
+ __u8 depth_to_show;
+ __u8 depth_check;
+ __u8 array_member:1,
+ array_terminated:1;
+ __u16 array_encoding;
+ __u32 type_id;
+ const struct btf_type *type;
+ const struct btf_member *member;
+ char name[BTF_DUMP_DATA_MAX_NAME_LEN];
+ int err;
+ } state;
+};
+
struct btf_dump {
const struct btf *btf;
const struct btf_ext *btf_ext;
@@ -89,6 +151,10 @@ struct btf_dump {
* name occurrences
*/
struct hashmap *ident_names;
+ /*
+ * data for typed display.
+ */
+ struct btf_dump_data data;
};
static size_t str_hash_fn(const void *key, void *ctx)
@@ -1438,3 +1504,911 @@ static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id)
{
return btf_dump_resolve_name(d, id, d->ident_names);
}
+
+static void __btf_dump_emit_type_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset);
+
+static const struct btf_type *skip_mods(const struct btf *btf,
+ __u32 id, __u32 *res_id)
+{
+ const struct btf_type *t = btf__type_by_id(btf, id);
+
+ while (btf_is_mod(t)) {
+ id = t->type;
+ t = btf__type_by_id(btf, t->type);
+ }
+
+ if (res_id)
+ *res_id = id;
+
+ return t;
+}
+
+#define BTF_MAX_ITER 10
+#define BTF_KIND_BIT(kind) (1ULL << kind)
+
+/*
+ * Populate dump->data.state.name with type name information.
+ * Format of type name is
+ *
+ * [.member_name = ] (type_name)
+ */
+static const char *btf_dump_data_name(struct btf_dump *d)
+{
+ /* BTF_MAX_ITER array suffixes "[]" */
+ const char *array_suffixes = "[][][][][][][][][][]";
+ const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
+ /* BTF_MAX_ITER pointer suffixes "*" */
+ const char *ptr_suffixes = "**********";
+ const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
+ const char *name = NULL, *prefix = "", *parens = "";
+ const struct btf_member *m = d->data.state.member;
+ const struct btf_type *t = d->data.state.type;
+ const struct btf_array *array;
+ __u32 id = d->data.state.type_id;
+ const char *member = NULL;
+ bool show_member = false;
+ __u64 kinds = 0;
+ int i;
+
+ d->data.state.name[0] = '\0';
+
+ /*
+ * Don't show type name if we're showing an array member;
+ * in that case we show the array type so don't need to repeat
+ * ourselves for each member.
+ */
+ if (d->data.state.array_member)
+ return "";
+
+ /* Retrieve member name, if any. */
+ if (m) {
+ member = btf_name_of(d, m->name_off);
+ show_member = strlen(member) > 0;
+ id = m->type;
+ }
+
+ /*
+ * Start with type_id, as we have resolved the struct btf_type *
+ * via btf_dump_emit_modifier_data() past the parent typedef to the
+ * child struct, int etc it is defined as. In such cases, the type_id
+ * still represents the starting type while the struct btf_type *
+ * in our d->data.state points at the resolved type of the typedef.
+ */
+ t = btf__type_by_id(d->btf, id);
+ if (!t)
+ return "";
+
+ /*
+ * The goal here is to build up the right number of pointer and
+ * array suffixes while ensuring the type name for a typedef
+ * is represented. Along the way we accumulate a list of
+ * BTF kinds we have encountered, since these will inform later
+ * display; for example, pointer types will not require an
+ * opening "{" for struct, we will just display the pointer value.
+ *
+ * We also want to accumulate the right number of pointer or array
+ * indices in the format string while iterating until we get to
+ * the typedef/pointee/array member target type.
+ *
+ * We start by pointing at the end of pointer and array suffix
+ * strings; as we accumulate pointers and arrays we move the pointer
+ * or array string backwards so it will show the expected number of
+ * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
+ * and/or arrays and typedefs are supported as a precaution.
+ *
+ * We also want to get typedef name while proceeding to resolve
+ * type it points to so that we can add parentheses if it is a
+ * "typedef struct" etc.
+ *
+ * Qualifiers ("const", "volatile", "restrict") are simply skipped
+ * as they complicate simple type name display without adding much
+ * in the case of displaying a cast in front of the data to be
+ * displayed.
+ */
+ for (i = 0; i < BTF_MAX_ITER; i++) {
+
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_TYPEDEF:
+ if (!name)
+ name = btf_name_of(d, t->name_off);
+ kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
+ id = t->type;
+ break;
+ case BTF_KIND_ARRAY:
+ kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
+ parens = "[";
+ if (!t)
+ return "";
+ array = btf_array(t);
+ if (array_suffix > array_suffixes)
+ array_suffix -= 2;
+ id = array->type;
+ break;
+ case BTF_KIND_PTR:
+ kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
+ if (ptr_suffix > ptr_suffixes)
+ ptr_suffix -= 1;
+ id = t->type;
+ break;
+ default:
+ id = 0;
+ break;
+ }
+ if (!id)
+ break;
+ t = skip_mods(d->btf, id, NULL);
+ }
+ /* We may not be able to represent this type; bail to be safe */
+ if (i == BTF_MAX_ITER) {
+ pr_warn("iters %d exceeded %d when displaying type name:[%u]\n",
+ i, BTF_MAX_ITER, id);
+ return "";
+ }
+
+ if (!name)
+ name = btf_name_of(d, t->name_off);
+
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_STRUCT:
+ case BTF_KIND_UNION:
+ prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
+ "struct" : "union";
+ /* if it's an array of struct/union, parens is already set */
+ if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
+ parens = "{";
+ break;
+ case BTF_KIND_ENUM:
+ prefix = "enum";
+ break;
+ default:
+ break;
+ }
+
+ /* pointer does not require parens */
+ if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
+ parens = "";
+ /* typedef does not require struct/union/enum prefix */
+ if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
+ prefix = "";
+
+ if (!name)
+ name = "";
+
+ /* Even if we don't want type name info, we want parentheses etc */
+ if (d->data.noname)
+ snprintf(d->data.state.name, sizeof(d->data.state.name), "%s",
+ parens);
+ else
+ snprintf(d->data.state.name, sizeof(d->data.state.name),
+ "%s%s%s(%s%s%s%s%s%s)%s",
+ /* first 3 strings comprise ".member = " */
+ show_member ? "." : "",
+ show_member ? member : "",
+ show_member ? " = " : "",
+ /* ...next is our prefix (struct, enum, etc) */
+ prefix,
+ strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
+ /* ...this is the type name itself */
+ name,
+ /* ...suffixed by the appropriate '*', '[]' suffixes */
+ strlen(name) > 0 && strlen(ptr_suffix) > 0 ? " " : "",
+ ptr_suffix,
+ array_suffix, parens);
+
+ return d->data.state.name;
+}
+
+static const char *btf_dump_data_indent(struct btf_dump *d)
+{
+ if (d->data.compact)
+ return "";
+ return spfx(d->data.indent_lvl + d->data.state.depth);
+}
+
+static const char *btf_dump_data_newline(struct btf_dump *d)
+{
+ return d->data.compact ? "" : "\n";
+}
+
+static const char *btf_dump_data_delim(struct btf_dump *d)
+{
+ if (d->data.state.depth == 0)
+ return "";
+
+ if (d->data.compact &&
+ d->data.state.type &&
+ BTF_INFO_KIND(d->data.state.type->info) == BTF_KIND_UNION)
+ return "|";
+
+ return ",";
+}
+
+static void btf_dump_data_printf(struct btf_dump *d,
+ const char *fmt, ...)
+{
+ va_list args;
+
+ /*
+ * Just checking if there is non-zero data to display at this depth,
+ * so nothing is displayed.
+ */
+ if (d->data.state.depth_check)
+ return;
+ va_start(args, fmt);
+ d->printf_fn(d->opts.ctx, fmt, args);
+ va_end(args);
+}
+
+/* Macros are used here as btf_type_value[s]() prepends and appends
+ * format specifiers to the format specifier passed in; these do the work of
+ * adding indentation, delimiters etc while the caller simply has to specify
+ * the type value(s) in the format specifier + value(s).
+ */
+#define btf_dump_emit_type_value(d, fmt, value) \
+ do { \
+ if ((value) != 0 || d->data.zero || \
+ d->data.state.depth == 0) { \
+ btf_dump_data_printf(d, "%s%s" fmt "%s%s", \
+ btf_dump_data_indent(d), \
+ btf_dump_data_name(d), \
+ value, \
+ btf_dump_data_delim(d), \
+ btf_dump_data_newline(d)); \
+ if (d->data.state.depth > \
+ d->data.state.depth_to_show) \
+ d->data.state.depth_to_show = \
+ d->data.state.depth; \
+ } \
+ } while (0)
+
+#define btf_dump_emit_type_values(d, fmt, ...) \
+ do { \
+ btf_dump_data_printf(d, "%s%s" fmt "%s%s", \
+ btf_dump_data_indent(d), \
+ btf_dump_data_name(d), \
+ __VA_ARGS__, \
+ btf_dump_data_delim(d), \
+ btf_dump_data_newline(d)); \
+ if (d->data.state.depth > \
+ d->data.state.depth_to_show) \
+ d->data.state.depth_to_show = \
+ d->data.state.depth; \
+ } while (0)
+
+/* Set the type we are starting to show. */
+static void btf_dump_start_type(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 type_id)
+{
+ d->data.state.type = t;
+ d->data.state.type_id = type_id;
+ d->data.state.name[0] = '\0';
+}
+
+static void btf_dump_end_type(struct btf_dump *d)
+{
+ d->data.state.type = NULL;
+ d->data.state.type_id = 0;
+ d->data.state.name[0] = '\0';
+}
+
+static void btf_dump_start_aggr_type(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 type_id)
+{
+ btf_dump_start_type(d, t, type_id);
+
+ btf_dump_data_printf(d, "%s%s%s",
+ btf_dump_data_indent(d),
+ btf_dump_data_name(d),
+ btf_dump_data_newline(d));
+ d->data.state.depth++;
+}
+
+static void btf_dump_end_aggr_type(struct btf_dump *d,
+ const char *suffix)
+{
+ d->data.state.depth--;
+ btf_dump_data_printf(d, "%s%s%s%s",
+ btf_dump_data_indent(d),
+ suffix,
+ btf_dump_data_delim(d),
+ btf_dump_data_newline(d));
+ btf_dump_end_type(d);
+}
+
+static void btf_dump_start_member(struct btf_dump *d,
+ const struct btf_member *m)
+{
+ d->data.state.member = m;
+}
+
+static void btf_dump_start_array_member(struct btf_dump *d)
+{
+ d->data.state.array_member = 1;
+ btf_dump_start_member(d, NULL);
+}
+
+static void btf_dump_end_member(struct btf_dump *d)
+{
+ d->data.state.member = NULL;
+}
+
+static void btf_dump_end_array_member(struct btf_dump *d)
+{
+ d->data.state.array_member = 0;
+ btf_dump_end_member(d);
+}
+
+static void btf_dump_start_array_type(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 type_id,
+ __u16 array_encoding)
+{
+ d->data.state.array_encoding = array_encoding;
+ d->data.state.array_terminated = 0;
+ btf_dump_start_aggr_type(d, t, type_id);
+}
+
+static void btf_dump_end_array_type(struct btf_dump *d)
+{
+ d->data.state.array_encoding = 0;
+ d->data.state.array_terminated = 0;
+ btf_dump_end_aggr_type(d, "]");
+}
+
+static void btf_dump_start_struct_type(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 type_id)
+{
+ btf_dump_start_aggr_type(d, t, type_id);
+}
+
+static void btf_dump_end_struct_type(struct btf_dump *d)
+{
+ btf_dump_end_aggr_type(d, "}");
+}
+
+static void btf_dump_emit_df_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ btf_dump_data_printf(d, "<unsupported kind:%u>",
+ BTF_INFO_KIND(t->info));
+}
+
+static void btf_dump_emit_int128(struct btf_dump *d, void *data)
+{
+ /* data points to a __int128 number.
+ * Suppose
+ * int128_num = *(__int128 *)data;
+ * The below formulas shows what upper_num and lower_num represents:
+ * upper_num = int128_num >> 64;
+ * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
+ */
+ __u64 upper_num, lower_num;
+
+#ifdef __BIG_ENDIAN_BITFIELD
+ upper_num = *(__u64 *)data;
+ lower_num = *(__u64 *)(data + 8);
+#else
+ upper_num = *(__u64 *)(data + 8);
+ lower_num = *(__u64 *)data;
+#endif
+ if (upper_num == 0)
+ btf_dump_emit_type_value(d, "0x%llx", lower_num);
+ else
+ btf_dump_emit_type_values(d, "0x%llx%016llx", upper_num,
+ lower_num);
+}
+
+static void btf_int128_shift(__u64 *print_num, __u16 left_shift_bits,
+ __u16 right_shift_bits)
+{
+ __u64 upper_num, lower_num;
+
+#ifdef __BIG_ENDIAN_BITFIELD
+ upper_num = print_num[0];
+ lower_num = print_num[1];
+#else
+ upper_num = print_num[1];
+ lower_num = print_num[0];
+#endif
+
+ /* shake out un-needed bits by shift/or operations */
+ if (left_shift_bits >= 64) {
+ upper_num = lower_num << (left_shift_bits - 64);
+ lower_num = 0;
+ } else {
+ upper_num = (upper_num << left_shift_bits) |
+ (lower_num >> (64 - left_shift_bits));
+ lower_num = lower_num << left_shift_bits;
+ }
+
+ if (right_shift_bits >= 64) {
+ lower_num = upper_num >> (right_shift_bits - 64);
+ upper_num = 0;
+ } else {
+ lower_num = (lower_num >> right_shift_bits) |
+ (upper_num << (64 - right_shift_bits));
+ upper_num = upper_num >> right_shift_bits;
+ }
+
+#ifdef __BIG_ENDIAN_BITFIELD
+ print_num[0] = upper_num;
+ print_num[1] = lower_num;
+#else
+ print_num[0] = lower_num;
+ print_num[1] = upper_num;
+#endif
+}
+
+static void btf_dump_emit_bitfield_data(struct btf_dump *d,
+ void *data,
+ __u8 bits_offset,
+ __u8 nr_bits)
+{
+ __u16 left_shift_bits, right_shift_bits;
+ __u8 nr_copy_bytes;
+ __u8 nr_copy_bits;
+ __u64 print_num[2] = {};
+
+ nr_copy_bits = nr_bits + bits_offset;
+ nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
+
+ memcpy(print_num, data, nr_copy_bytes);
+
+#ifdef __BIG_ENDIAN_BITFIELD
+ left_shift_bits = bits_offset;
+#else
+ left_shift_bits = BITS_PER_U128 - nr_copy_bits;
+#endif
+ right_shift_bits = BITS_PER_U128 - nr_bits;
+
+ btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
+ btf_dump_emit_int128(d, print_num);
+}
+
+static void btf_dump_emit_int_bits(struct btf_dump *d,
+ const struct btf_type *t,
+ void *data,
+ __u8 bits_offset)
+{
+ __u32 int_data = btf_int(t);
+ __u8 nr_bits = BTF_INT_BITS(int_data);
+ __u8 total_bits_offset;
+
+ /*
+ * bits_offset is at most 7.
+ * BTF_INT_OFFSET() cannot exceed 128 bits.
+ */
+ total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
+ data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
+ bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
+ btf_dump_emit_bitfield_data(d, data, bits_offset, nr_bits);
+}
+
+static void btf_dump_emit_int_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 type_id,
+ void *data,
+ __u8 bits_offset)
+{
+ __u32 int_data = btf_int(t);
+ __u8 encoding = BTF_INT_ENCODING(int_data);
+ bool sign = encoding & BTF_INT_SIGNED;
+ __u8 nr_bits = BTF_INT_BITS(int_data);
+
+ btf_dump_start_type(d, t, type_id);
+
+ if (bits_offset || BTF_INT_OFFSET(int_data) ||
+ BITS_PER_BYTE_MASKED(nr_bits)) {
+ btf_dump_emit_int_bits(d, t, data, bits_offset);
+ goto out;
+ }
+
+ switch (nr_bits) {
+ case 128:
+ btf_dump_emit_int128(d, data);
+ break;
+ case 64:
+ if (sign)
+ btf_dump_emit_type_value(d, "%lld", *(__s64 *)data);
+ else
+ btf_dump_emit_type_value(d, "%llu", *(__u64 *)data);
+ break;
+ case 32:
+ if (sign)
+ btf_dump_emit_type_value(d, "%d", *(__s32 *)data);
+ else
+ btf_dump_emit_type_value(d, "%u", *(__u32 *)data);
+ break;
+ case 16:
+ if (sign)
+ btf_dump_emit_type_value(d, "%d", *(__s16 *)data);
+ else
+ btf_dump_emit_type_value(d, "%u", *(__u16 *)data);
+ break;
+ case 8:
+ if (d->data.state.array_encoding == BTF_INT_CHAR) {
+ /* check for null terminator */
+ if (d->data.state.array_terminated)
+ break;
+ if (*(char *)data == '\0') {
+ d->data.state.array_terminated = 1;
+ break;
+ }
+ if (isprint(*(char *)data)) {
+ btf_dump_emit_type_value(d, "'%c'",
+ *(char *)data);
+ break;
+ }
+ }
+ if (sign)
+ btf_dump_emit_type_value(d, "%d", *(__s8 *)data);
+ else
+ btf_dump_emit_type_value(d, "%u", *(__u8 *)data);
+ break;
+ default:
+ btf_dump_emit_int_bits(d, t, data, bits_offset);
+ break;
+ }
+out:
+ btf_dump_end_type(d);
+}
+
+static void btf_dump_emit_modifier_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ t = skip_mods_and_typedefs(d->btf, id, NULL);
+ __btf_dump_emit_type_data(d, t, id, data, bits_offset);
+}
+
+static void btf_dump_emit_var_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ __u32 linkage = btf_var(t)->linkage;
+
+ btf_dump_data_printf(d, "%s%s =",
+ linkage ? "" : "static ",
+ btf_name_of(d, t->name_off));
+ t = btf__type_by_id(d->btf, t->type);
+ __btf_dump_emit_type_data(d, t, t->type, data, bits_offset);
+}
+
+static void __btf_dump_emit_array_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ const struct btf_array *array = btf_array(t);
+ const struct btf_type *elem_type;
+ __u32 i, elem_size = 0, elem_type_id;
+ __u16 encoding = 0;
+
+ elem_type_id = array->type;
+ elem_type = skip_mods_and_typedefs(d->btf, elem_type_id, NULL);
+ if (elem_type && btf_has_size(elem_type))
+ elem_size = elem_type->size;
+
+ if (elem_type && btf_is_int(elem_type)) {
+ __u32 int_type = btf_int(elem_type);
+
+ encoding = BTF_INT_ENCODING(int_type);
+
+ /*
+ * BTF_INT_CHAR encoding never seems to be set for
+ * char arrays, so if size is 1 and element is
+ * printable as a char, we'll do that.
+ */
+ if (elem_size == 1)
+ encoding = BTF_INT_CHAR;
+ }
+
+ btf_dump_start_array_type(d, t, id, encoding);
+
+ if (!elem_type)
+ goto out;
+
+ for (i = 0; i < array->nelems; i++) {
+
+ btf_dump_start_array_member(d);
+
+ __btf_dump_emit_type_data(d, elem_type, elem_type_id,
+ data, bits_offset);
+ data += elem_size;
+
+ btf_dump_end_array_member(d);
+
+ if (d->data.state.array_terminated)
+ break;
+ }
+out:
+ btf_dump_end_array_type(d);
+}
+
+static void btf_dump_emit_array_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ const struct btf_member *m = d->data.state.member;
+
+ /*
+ * First check if any members would be shown (are non-zero).
+ * See comments above "struct btf_dump_data" definition for more
+ * details on how this works at a high-level.
+ */
+ if (d->data.state.depth > 0 && !d->data.zero) {
+ if (!d->data.state.depth_check) {
+ d->data.state.depth_check = d->data.state.depth + 1;
+ d->data.state.depth_to_show = 0;
+ }
+ __btf_dump_emit_array_data(d, t, id, data, bits_offset);
+ d->data.state.member = m;
+
+ if (d->data.state.depth_check != d->data.state.depth + 1)
+ return;
+ d->data.state.depth_check = 0;
+
+ if (d->data.state.depth_to_show <= d->data.state.depth)
+ return;
+ /*
+ * Reaching here indicates we have recursed and found
+ * non-zero array member(s).
+ */
+ }
+ __btf_dump_emit_array_data(d, t, id, data, bits_offset);
+}
+
+#define for_each_member(i, struct_type, member) \
+ for (i = 0, member = btf_members(struct_type); \
+ i < btf_vlen(struct_type); \
+ i++, member++)
+
+static void __btf_dump_emit_struct_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ const struct btf_member *member;
+ __u32 i;
+
+ btf_dump_start_struct_type(d, t, id);
+
+ for_each_member(i, t, member) {
+ const struct btf_type *member_type;
+ __u32 member_offset, bitfield_size;
+ __u32 bytes_offset;
+ __u8 bits8_offset;
+
+ member_type = btf__type_by_id(d->btf, member->type);
+ btf_dump_start_member(d, member);
+
+ member_offset = btf_member_bit_offset(t, i);
+ bitfield_size = btf_member_bitfield_size(t, i);
+ bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
+ bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
+ if (bitfield_size) {
+ btf_dump_start_type(d, member_type, member->type);
+ btf_dump_emit_bitfield_data(d,
+ data + bytes_offset,
+ bits8_offset,
+ bitfield_size);
+ btf_dump_end_type(d);
+ } else {
+ __btf_dump_emit_type_data(d, member_type, member->type,
+ data + bytes_offset, bits8_offset);
+ }
+ btf_dump_end_member(d);
+ }
+ btf_dump_end_struct_type(d);
+}
+
+static void btf_dump_emit_struct_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ const struct btf_member *m = d->data.state.member;
+
+ /*
+ * First check if any members would be shown (are non-zero).
+ * See comments above "struct btf_dump_data" definition for more
+ * details on how this works at a high-level.
+ */
+ if (d->data.state.depth > 0 && !d->data.zero) {
+ if (!d->data.state.depth_check) {
+ d->data.state.depth_check = d->data.state.depth + 1;
+ d->data.state.depth_to_show = 0;
+ }
+ __btf_dump_emit_struct_data(d, t, id, data, bits_offset);
+ /* Restore saved member data here */
+ d->data.state.member = m;
+ if (d->data.state.depth_check != d->data.state.depth + 1)
+ return;
+ d->data.state.depth_check = 0;
+
+ if (d->data.state.depth_to_show <= d->data.state.depth)
+ return;
+ /*
+ * Reaching here indicates we have recursed and found
+ * non-zero child values.
+ */
+ }
+
+ __btf_dump_emit_struct_data(d, t, id, data, bits_offset);
+}
+
+static void btf_dump_emit_ptr_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ btf_dump_start_type(d, t, id);
+
+ btf_dump_emit_type_value(d, "%p", *(void **)data);
+ btf_dump_end_type(d);
+}
+
+static void btf_dump_emit_enum_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ const struct btf_enum *enums = btf_enum(t);
+ __s64 value;
+ __u16 i;
+
+ btf_dump_start_type(d, t, id);
+
+ switch (t->size) {
+ case 8:
+ value = *(__s64 *)data;
+ break;
+ case 4:
+ value = *(__s32 *)data;
+ break;
+ case 2:
+ value = *(__s16 *)data;
+ break;
+ case 1:
+ value = *(__s8 *)data;
+ break;
+ default:
+ pr_warn("unexpected size %d for enum, id:[%u]\n", t->size,
+ id);
+ d->data.state.err = -EINVAL;
+ return;
+ }
+
+ for (i = 0; i < btf_vlen(t); i++) {
+ if (value == enums[i].val) {
+ btf_dump_emit_type_value(d, "%s",
+ btf_name_of(d,
+ enums[i].name_off));
+ btf_dump_end_type(d);
+ return;
+ }
+ }
+
+ btf_dump_emit_type_value(d, "%d", value);
+ btf_dump_end_type(d);
+}
+
+#define for_each_vsi(i, struct_type, member) \
+ for (i = 0, member = btf_var_secinfos(struct_type); \
+ i < btf_vlen(struct_type); \
+ i++, member++)
+
+static void btf_dump_emit_datasec_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ const struct btf_var_secinfo *vsi;
+ const struct btf_type *var;
+ __u32 i;
+
+ btf_dump_start_type(d, t, id);
+
+ btf_dump_emit_type_value(d, "section (\"%s\") = {",
+ btf_name_of(d, t->name_off));
+ for_each_vsi(i, t, vsi) {
+ var = btf__type_by_id(d->btf, vsi->type);
+ if (i)
+ btf_dump_data_printf(d, ",");
+ __btf_dump_emit_type_data(d, var, vsi->type,
+ data + vsi->offset,
+ bits_offset);
+ }
+ btf_dump_end_type(d);
+}
+
+typedef void (*btf_dump_emit_kind_data)(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset);
+
+static btf_dump_emit_kind_data dump_emit_kind_data[NR_BTF_KINDS] = {
+ &btf_dump_emit_df_data,
+ &btf_dump_emit_int_data,
+ &btf_dump_emit_ptr_data,
+ &btf_dump_emit_array_data,
+ &btf_dump_emit_struct_data,
+ &btf_dump_emit_struct_data,
+ &btf_dump_emit_enum_data,
+ &btf_dump_emit_df_data,
+ &btf_dump_emit_modifier_data,
+ &btf_dump_emit_modifier_data,
+ &btf_dump_emit_modifier_data,
+ &btf_dump_emit_modifier_data,
+ &btf_dump_emit_df_data,
+ &btf_dump_emit_df_data,
+ &btf_dump_emit_var_data,
+ &btf_dump_emit_datasec_data,
+};
+
+static void __btf_dump_emit_type_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ void *data,
+ __u8 bits_offset)
+{
+ dump_emit_kind_data[BTF_INFO_KIND(t->info)](d, t, id, data,
+ bits_offset);
+}
+
+static void btf_dump_emit_type_data(struct btf_dump *d, __u32 id, void *data)
+{
+ const struct btf_type *t = btf__type_by_id(d->btf, id);
+
+ memset(&d->data.state, 0, sizeof(d->data.state));
+
+ if (!t) {
+ pr_warn("no type info, id [%u]\n", id);
+ d->data.state.err = -EINVAL;
+ return;
+ }
+
+ __btf_dump_emit_type_data(d, t, id, data, 0);
+}
+
+int btf_dump__emit_type_data(struct btf_dump *d, __u32 id,
+ const struct btf_dump_emit_type_data_opts *opts,
+ void *data)
+{
+ int err;
+
+ if (!OPTS_VALID(opts, btf_dump_emit_type_data_opts))
+ return -EINVAL;
+
+ d->data.indent_lvl = OPTS_GET(opts, indent_level, 0);
+ d->data.compact = OPTS_GET(opts, compact, false);
+ d->data.noname = OPTS_GET(opts, noname, false);
+ d->data.zero = OPTS_GET(opts, zero, false);
+ btf_dump_emit_type_data(d, id, data);
+ err = d->data.state.err;
+ memset(&d->data, 0, sizeof(d->data));
+ return err;
+}
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 1c0fd2d..b81c069 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -350,3 +350,8 @@ LIBBPF_0.3.0 {
xsk_setup_xdp_prog;
xsk_socket__update_xskmap;
} LIBBPF_0.2.0;
+
+LIBBPF_0.4.0 {
+ global:
+ btf_dump__emit_type_data;
+} LIBBPF_0.3.0;
--
1.8.3.1