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__dump_type_data(struct btf_dump *d, __u32 id,
void *data, size_t data_sz,
const struct btf_dump_type_data_opts *opts);
...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 user-specified indent string which will be printed once per
indent level; if NULL, tab is chosen but any string <= 32 chars
can be provided.
- 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
- skip_names: omit member names
- emit_zeroes: 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,
},
},
...
If the data structure is larger than the *data_sz*
number of bytes that are available in *data*, as much
of the data as possible will be dumped and -E2BIG will
be returned. This is useful as tracers will sometimes
not be able to capture all of the data associated with
a type; for example a "struct task_struct" is ~16k.
Being able to specify that only a subset is available is
important for such cases. On success, the amount of data
dumped is returned.
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
tools/lib/bpf/btf.h | 19 ++
tools/lib/bpf/btf_dump.c | 833 ++++++++++++++++++++++++++++++++++++++++++++++-
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 848 insertions(+), 5 deletions(-)
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index b54f1c3..5240973 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -184,6 +184,25 @@ 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_type_data_opts {
+ /* size of this struct, for forward/backward compatibility */
+ size_t sz;
+ int indent_level;
+ const char *indent_str;
+ /* below match "show" flags for bpf_show_snprintf() */
+ bool compact; /* no newlines/tabs */
+ bool skip_names; /* skip member/type names */
+ bool emit_zeroes; /* show 0-valued fields */
+ size_t :0;
+};
+#define btf_dump_type_data_opts__last_field emit_zeroes
+
+LIBBPF_API int
+btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
+ const void *data, size_t data_sz,
+ const struct btf_dump_type_data_opts *opts);
+
/*
* 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 5dc6b517..c59fa07 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>
@@ -53,6 +55,28 @@ struct btf_dump_type_aux_state {
__u8 referenced: 1;
};
+/* indent string length; one indent string is added for each indent level */
+#define BTF_DATA_INDENT_STR_LEN 32
+
+/*
+ * Common internal data for BTF type data dump operations.
+ */
+struct btf_dump_data {
+ const void *data_end; /* end of valid data to show */
+ bool compact;
+ bool skip_names;
+ bool emit_zeroes;
+ __u8 indent_lvl; /* base indent level */
+ char indent_str[BTF_DATA_INDENT_STR_LEN + 1];
+ /* below are used during iteration */
+ struct {
+ __u8 depth;
+ __u8 array_member:1,
+ array_terminated:1,
+ array_ischar:1;
+ } state;
+};
+
struct btf_dump {
const struct btf *btf;
const struct btf_ext *btf_ext;
@@ -60,6 +84,7 @@ struct btf_dump {
struct btf_dump_opts opts;
int ptr_sz;
bool strip_mods;
+ bool skip_anon_defs;
int last_id;
/* per-type auxiliary state */
@@ -89,6 +114,10 @@ struct btf_dump {
* name occurrences
*/
struct hashmap *ident_names;
+ /*
+ * data for typed display; allocated if needed.
+ */
+ struct btf_dump_data *typed_dump;
};
static size_t str_hash_fn(const void *key, void *ctx)
@@ -765,11 +794,11 @@ static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
break;
case BTF_KIND_FUNC_PROTO: {
const struct btf_param *p = btf_params(t);
- __u16 vlen = btf_vlen(t);
+ __u16 n = btf_vlen(t);
int i;
btf_dump_emit_type(d, t->type, cont_id);
- for (i = 0; i < vlen; i++, p++)
+ for (i = 0; i < n; i++, p++)
btf_dump_emit_type(d, p->type, cont_id);
break;
@@ -852,8 +881,9 @@ static void btf_dump_emit_bit_padding(const struct btf_dump *d,
static void btf_dump_emit_struct_fwd(struct btf_dump *d, __u32 id,
const struct btf_type *t)
{
- btf_dump_printf(d, "%s %s",
+ btf_dump_printf(d, "%s%s%s",
btf_is_struct(t) ? "struct" : "union",
+ t->name_off ? " " : "",
btf_dump_type_name(d, id));
}
@@ -1259,7 +1289,7 @@ static void btf_dump_emit_type_chain(struct btf_dump *d,
case BTF_KIND_UNION:
btf_dump_emit_mods(d, decls);
/* inline anonymous struct/union */
- if (t->name_off == 0)
+ if (t->name_off == 0 && !d->skip_anon_defs)
btf_dump_emit_struct_def(d, id, t, lvl);
else
btf_dump_emit_struct_fwd(d, id, t);
@@ -1267,7 +1297,7 @@ static void btf_dump_emit_type_chain(struct btf_dump *d,
case BTF_KIND_ENUM:
btf_dump_emit_mods(d, decls);
/* inline anonymous enum */
- if (t->name_off == 0)
+ if (t->name_off == 0 && !d->skip_anon_defs)
btf_dump_emit_enum_def(d, id, t, lvl);
else
btf_dump_emit_enum_fwd(d, id, t);
@@ -1392,6 +1422,39 @@ static void btf_dump_emit_type_chain(struct btf_dump *d,
btf_dump_emit_name(d, fname, last_was_ptr);
}
+/* show type name as (type_name) */
+static void btf_dump_emit_type_cast(struct btf_dump *d, __u32 id,
+ bool top_level)
+{
+ const struct btf_type *t;
+
+ /* for array members, we don't bother emitting type name for each
+ * member to avoid the redundancy of
+ * .name = (char[4])[(char)'f',(char)'o',(char)'o',]
+ */
+ if (d->typed_dump->state.array_member)
+ return;
+
+ /* avoid type name specification for variable/section; it will be done
+ * for the associated variable value(s).
+ */
+ t = btf__type_by_id(d->btf, id);
+ if (btf_is_var(t) || btf_is_datasec(t))
+ return;
+
+ if (top_level)
+ btf_dump_printf(d, "(");
+
+ d->skip_anon_defs = true;
+ d->strip_mods = true;
+ btf_dump_emit_type_decl(d, id, "", 0);
+ d->strip_mods = false;
+ d->skip_anon_defs = false;
+
+ if (top_level)
+ btf_dump_printf(d, ")");
+}
+
/* return number of duplicates (occurrences) of a given name */
static size_t btf_dump_name_dups(struct btf_dump *d, struct hashmap *name_map,
const char *orig_name)
@@ -1442,3 +1505,763 @@ static const char *btf_dump_ident_name(struct btf_dump *d, __u32 id)
{
return btf_dump_resolve_name(d, id, d->ident_names);
}
+
+static int btf_dump_dump_type_data(struct btf_dump *d,
+ const char *fname,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data,
+ __u8 bits_offset,
+ __u8 bit_sz);
+
+static const char *btf_dump_data_newline(struct btf_dump *d)
+{
+ return (d->typed_dump->compact || d->typed_dump->state.depth == 0) ?
+ "" : "\n";
+}
+
+static const char *btf_dump_data_delim(struct btf_dump *d)
+{
+ return d->typed_dump->state.depth == 0 ? "" : ",";
+}
+
+static void btf_dump_data_pfx(struct btf_dump *d)
+{
+ int i, lvl = d->typed_dump->indent_lvl + d->typed_dump->state.depth;
+
+ if (d->typed_dump->compact)
+ return;
+
+ for (i = 0; i < lvl; i++)
+ btf_dump_printf(d, "%s", d->typed_dump->indent_str);
+}
+
+/* A macro is used here as btf_type_value[s]() appends format specifiers
+ * to the format specifier passed in; these do the work of appending
+ * delimiters etc while the caller simply has to specify the type values
+ * in the format specifier + value(s).
+ */
+#define btf_dump_type_values(d, fmt, ...) \
+ btf_dump_printf(d, fmt "%s%s", \
+ __VA_ARGS__, \
+ btf_dump_data_delim(d), \
+ btf_dump_data_newline(d))
+
+static int btf_dump_unsupported_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id)
+{
+ btf_dump_printf(d, "<unsupported kind:%u>", btf_kind(t));
+ return -ENOTSUP;
+}
+
+static void btf_dump_int128(struct btf_dump *d,
+ const struct btf_type *t,
+ const void *data)
+{
+ __int128 num = *(__int128 *)data;
+
+ if ((num >> 64) == 0)
+ btf_dump_type_values(d, "0x%llx", (long long)num);
+ else
+ btf_dump_type_values(d, "0x%llx%016llx", (long long)num >> 32,
+ (long long)num);
+}
+
+static unsigned __int128 btf_dump_bitfield_get_data(struct btf_dump *d,
+ const void *data,
+ __u8 bits_offset,
+ __u8 bit_sz)
+{
+ __u16 left_shift_bits, right_shift_bits;
+ __u8 nr_copy_bits, nr_copy_bytes, i;
+ unsigned __int128 num = 0, ret;
+ const __u8 *bytes = data;
+
+ /* Bitfield value retrieval is done in two steps; first relevant bytes are
+ * stored in num, then we left/right shift num to eliminate irrelevant bits.
+ */
+ nr_copy_bits = bit_sz + bits_offset;
+ nr_copy_bytes = roundup(nr_copy_bits, 8) / 8;
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+ for (i = 0; i < nr_copy_bytes; i++)
+ num += bytes[i] << (8 * i);
+#elif __BYTE_ORDER == __BIG_ENDIAN
+ for (i = nr_copy_bytes - 1; i >= 0; i--)
+ num += bytes[i] << (8 * i);
+#else
+# error "Unrecognized __BYTE_ORDER__"
+#endif
+ left_shift_bits = 128 - nr_copy_bits;
+ right_shift_bits = 128 - bit_sz;
+
+ ret = (num << left_shift_bits) >> right_shift_bits;
+
+ return ret;
+}
+
+static int btf_dump_bitfield_data(struct btf_dump *d,
+ const struct btf_type *t,
+ const void *data,
+ __u8 bits_offset,
+ __u8 bit_sz)
+{
+ unsigned __int128 print_num;
+
+ print_num = btf_dump_bitfield_get_data(d, data, bits_offset, bit_sz);
+ btf_dump_int128(d, t, &print_num);
+
+ return 0;
+}
+
+static int btf_dump_int_bits(struct btf_dump *d,
+ const struct btf_type *t,
+ const void *data,
+ __u8 bits_offset,
+ __u8 bit_sz)
+{
+ data += bits_offset / 8;
+ return btf_dump_bitfield_data(d, t, data, bits_offset, bit_sz);
+}
+
+static int btf_dump_int_bits_check_zero(struct btf_dump *d,
+ const struct btf_type *t,
+ const void *data,
+ __u8 bits_offset,
+ __u8 bit_sz)
+{
+ __int128 print_num;
+
+ data += bits_offset / 8;
+ print_num = btf_dump_bitfield_get_data(d, data, bits_offset, bit_sz);
+ if (print_num == 0)
+ return -ENODATA;
+ return 0;
+}
+
+static int btf_dump_int_check_zero(struct btf_dump *d,
+ const struct btf_type *t,
+ const void *data,
+ __u8 bits_offset)
+{
+ __u8 nr_bits = btf_int_bits(t);
+ bool zero = false;
+
+ if (bits_offset)
+ return btf_dump_int_bits_check_zero(d, t, data, bits_offset, 0);
+
+ switch (nr_bits) {
+ case 128:
+ zero = *(__int128 *)data == 0;
+ break;
+ case 64:
+ zero = *(__s64 *)data == 0;
+ break;
+ case 32:
+ zero = *(__s32 *)data == 0;
+ break;
+ case 16:
+ zero = *(__s16 *)data == 0;
+ break;
+ case 8:
+ zero = *(__s8 *)data == 0;
+ break;
+ default:
+ pr_warn("unexpected nr_bits %d for int\n", nr_bits);
+ return -EINVAL;
+ }
+ if (zero)
+ return -ENODATA;
+ return 0;
+}
+
+static int btf_dump_int_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 type_id,
+ const void *data,
+ __u8 bits_offset)
+{
+ __u8 encoding = btf_int_encoding(t);
+ bool sign = encoding & BTF_INT_SIGNED;
+ __u8 nr_bits = btf_int_bits(t);
+
+ if (bits_offset)
+ return btf_dump_int_bits(d, t, data, bits_offset, 0);
+
+ switch (nr_bits) {
+ case 128:
+ btf_dump_int128(d, t, data);
+ break;
+ case 64:
+ if (sign)
+ btf_dump_type_values(d, "%lld", *(long long *)data);
+ else
+ btf_dump_type_values(d, "%llu", *(unsigned long long *)data);
+ break;
+ case 32:
+ if (sign)
+ btf_dump_type_values(d, "%d", *(__s32 *)data);
+ else
+ btf_dump_type_values(d, "%u", *(__u32 *)data);
+ break;
+ case 16:
+ if (sign)
+ btf_dump_type_values(d, "%d", *(__s16 *)data);
+ else
+ btf_dump_type_values(d, "%u", *(__u16 *)data);
+ break;
+ case 8:
+ if (d->typed_dump->state.array_ischar) {
+ /* check for null terminator */
+ if (d->typed_dump->state.array_terminated)
+ break;
+ if (*(char *)data == '\0') {
+ d->typed_dump->state.array_terminated = 1;
+ break;
+ }
+ if (isprint(*(char *)data)) {
+ btf_dump_type_values(d, "'%c'", *(char *)data);
+ break;
+ }
+ }
+ if (sign)
+ btf_dump_type_values(d, "%d", *(__s8 *)data);
+ else
+ btf_dump_type_values(d, "%u", *(__u8 *)data);
+ break;
+ default:
+ pr_warn("unexpected nr_bits %d for id [%u]\n", nr_bits, type_id);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int btf_dump_float_check_zero(struct btf_dump *d,
+ const struct btf_type *t,
+ const void *data)
+{
+ static __u8 bytecmp[16] = {};
+ int nr_bytes = t->size;
+
+ if (nr_bytes > 16 || nr_bytes < 2) {
+ pr_warn("unexpected size %d for float\n", nr_bytes);
+ return -EINVAL;
+ }
+ if (memcmp(data, bytecmp, nr_bytes) == 0)
+ return -ENOMSG;
+
+ return 0;
+}
+
+static int btf_dump_float_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 type_id,
+ const void *data,
+ __u8 bits_offset)
+{
+ int nr_bytes = t->size;
+
+ switch (nr_bytes) {
+ case 16:
+ btf_dump_type_values(d, "%Lf", *(long double *)data);
+ break;
+ case 8:
+ btf_dump_type_values(d, "%f", *(double *)data);
+ break;
+ case 4:
+ btf_dump_type_values(d, "%f", *(float *)data);
+ break;
+ default:
+ pr_warn("unexpected size %d for id [%u]\n", nr_bytes, type_id);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int btf_dump_var_data(struct btf_dump *d,
+ const struct btf_type *v,
+ __u32 id,
+ const void *data)
+{
+ enum btf_func_linkage linkage = btf_var(v)->linkage;
+ const struct btf_type *t;
+ const char *l;
+ __u32 type_id;
+
+ switch (linkage) {
+ case BTF_FUNC_STATIC:
+ l = "static ";
+ break;
+ case BTF_FUNC_EXTERN:
+ l = "extern ";
+ break;
+ case BTF_FUNC_GLOBAL:
+ default:
+ l = "";
+ break;
+ }
+
+ /* format of output here is [linkage] [type] [varname] = (type)value,
+ * for example "static int cpu_profile_flip = (int)1"
+ */
+ btf_dump_printf(d, "%s", l);
+ type_id = v->type;
+ t = btf__type_by_id(d->btf, type_id);
+ btf_dump_emit_type_cast(d, type_id, false);
+ btf_dump_printf(d, " %s = ", btf_name_of(d, v->name_off));
+ return btf_dump_dump_type_data(d, NULL, t, type_id, data, 0, 0);
+}
+
+static int btf_dump_array_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data)
+{
+ const struct btf_array *array = btf_array(t);
+ const struct btf_type *elem_type;
+ __u32 i, elem_size = 0, elem_type_id;
+ int array_member;
+
+ elem_type_id = array->type;
+ elem_type = skip_mods_and_typedefs(d->btf, elem_type_id, NULL);
+ elem_size = btf__resolve_size(d->btf, elem_type_id);
+ if (elem_size <= 0) {
+ pr_warn("unexpected elem size %d for array type [%u]\n", elem_size, id);
+ return -EINVAL;
+ }
+
+ if (btf_is_int(elem_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)
+ d->typed_dump->state.array_ischar = true;
+ }
+
+ d->typed_dump->state.depth++;
+ btf_dump_printf(d, "[%s", btf_dump_data_newline(d));
+
+ /* may be a multidimensional array, so store current "is array member"
+ * status so we can restore it correctly later.
+ */
+ array_member = d->typed_dump->state.array_member;
+ d->typed_dump->state.array_member = 1;
+ for (i = 0;
+ i < array->nelems && !d->typed_dump->state.array_terminated;
+ i++) {
+ btf_dump_dump_type_data(d, NULL, elem_type, elem_type_id, data, 0, 0);
+ data += elem_size;
+ }
+ d->typed_dump->state.array_member = array_member;
+ d->typed_dump->state.depth--;
+ btf_dump_data_pfx(d);
+ btf_dump_printf(d, "]%s%s", btf_dump_data_delim(d), btf_dump_data_newline(d));
+
+ return 0;
+}
+
+static int btf_dump_struct_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data)
+{
+ const struct btf_member *m = btf_members(t);
+ __u16 n = btf_vlen(t);
+ int i, err;
+
+ d->typed_dump->state.depth++;
+ btf_dump_printf(d, "{%s", btf_dump_data_newline(d));
+
+ for (i = 0; i < n; i++, m++) {
+ const struct btf_type *mtype;
+ const char *mname;
+ __u32 moffset;
+ __u8 bit_sz;
+
+ mtype = btf__type_by_id(d->btf, m->type);
+ mname = btf_name_of(d, m->name_off);
+ moffset = btf_member_bit_offset(t, i);
+
+ bit_sz = btf_member_bitfield_size(t, i);
+ err = btf_dump_dump_type_data(d, mname, mtype, m->type, data + moffset / 8,
+ moffset % 8, bit_sz);
+ if (err < 0)
+ return err;
+ }
+ d->typed_dump->state.depth--;
+ btf_dump_data_pfx(d);
+ btf_dump_printf(d, "}%s%s", btf_dump_data_delim(d), btf_dump_data_newline(d));
+ return err;
+}
+
+static int btf_dump_ptr_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data)
+{
+ btf_dump_type_values(d, "%p", *(void **)data);
+ return 0;
+}
+
+static int btf_dump_get_enum_value(const struct btf_type *t,
+ const void *data,
+ __u32 id,
+ __s64 *value)
+{
+ switch (t->size) {
+ case 8:
+ *value = *(__s64 *)data;
+ return 0;
+ case 4:
+ *value = *(__s32 *)data;
+ return 0;
+ case 2:
+ *value = *(__s16 *)data;
+ return 0;
+ case 1:
+ *value = *(__s8 *)data;
+ default:
+ pr_warn("unexpected size %d for enum, id:[%u]\n", t->size, id);
+ return -EINVAL;
+ }
+}
+
+static int btf_dump_enum_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data)
+{
+ const struct btf_enum *e;
+ __s64 value;
+ int i, err;
+
+ err = btf_dump_get_enum_value(t, data, id, &value);
+ if (err)
+ return err;
+
+ for (i = 0, e = btf_enum(t); i < btf_vlen(t); i++, e++) {
+ if (value != e->val)
+ continue;
+ btf_dump_type_values(d, "%s", btf_name_of(d, e->name_off));
+ return 0;
+ }
+
+ btf_dump_type_values(d, "%d", value);
+ return 0;
+}
+
+static int btf_dump_datasec_data(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data)
+{
+ const struct btf_var_secinfo *vsi;
+ const struct btf_type *var;
+ __u32 i;
+ int err;
+
+ btf_dump_type_values(d, "SEC(\"%s\") ",
+ btf_name_of(d, t->name_off));
+ for (i = 0, vsi = btf_var_secinfos(t); i < btf_vlen(t); i++, vsi++) {
+ var = btf__type_by_id(d->btf, vsi->type);
+ err = btf_dump_dump_type_data(d, NULL, var, vsi->type, data + vsi->offset, 0, 0);
+ if (err < 0)
+ return err;
+ btf_dump_printf(d, ";");
+ }
+ return 0;
+}
+
+/* return size of type, or if base type overflows, return -E2BIG. */
+static int btf_dump_type_data_check_overflow(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data,
+ __u8 bits_offset)
+{
+ __s64 size = btf__resolve_size(d->btf, id);
+
+ if (size < 0 || size >= INT_MAX) {
+ pr_warn("unexpected size [%lld] for id [%u]\n",
+ size, id);
+ return -EINVAL;
+ }
+
+ /* Only do overflow checking for base types; we do not want to
+ * avoid showing part of a struct, union or array, even if we
+ * do not have enough data to show the full object. By
+ * restricting overflow checking to base types we can ensure
+ * that partial display succeeds, while avoiding overflowing
+ * and using bogus data for display.
+ */
+ t = skip_mods_and_typedefs(d->btf, id, NULL);
+ if (!t) {
+ pr_warn("unexpected error skipping mods/typedefs for id [%u]\n",
+ id);
+ return -EINVAL;
+ }
+
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_INT:
+ case BTF_KIND_PTR:
+ case BTF_KIND_ENUM:
+ if (data + bits_offset / 8 + size > d->typed_dump->data_end)
+ return -E2BIG;
+ break;
+ default:
+ break;
+ }
+ return (int)size;
+}
+
+static int btf_dump_type_data_check_zero(struct btf_dump *d,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data,
+ __u8 bits_offset,
+ __u8 bit_sz)
+{
+ __s64 value;
+ int i, err;
+
+ /* toplevel exceptions; we show zero values if
+ * - we ask for them (emit_zeros)
+ * - if we are at top-level so we see "struct empty { }"
+ * - or if we are an array member and the array is non-empty and
+ * not a char array; we don't want to be in a situation where we
+ * have an integer array 0, 1, 0, 1 and only show non-zero values.
+ * If the array contains zeroes only, or is a char array starting
+ * with a '\0', the array-level check_zero() will prevent showing it;
+ * we are concerned with determining zero value at the array member
+ * level here.
+ */
+ if (d->typed_dump->emit_zeroes || d->typed_dump->state.depth == 0 ||
+ (d->typed_dump->state.array_member &&
+ !d->typed_dump->state.array_ischar))
+ return 0;
+
+ t = skip_mods_and_typedefs(d->btf, id, NULL);
+ if (!t) {
+ pr_warn("unexpected error skipping mods/typedefs for id [%u]\n",
+ id);
+ return -EINVAL;
+ }
+
+
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_INT:
+ if (bit_sz)
+ return btf_dump_int_bits_check_zero(d, t, data,
+ bits_offset, bit_sz);
+ return btf_dump_int_check_zero(d, t, data, bits_offset);
+ case BTF_KIND_FLOAT:
+ return btf_dump_float_check_zero(d, t, data);
+ case BTF_KIND_PTR:
+ if (*((void **)data) == NULL)
+ return -ENODATA;
+ return 0;
+ case BTF_KIND_ARRAY: {
+ const struct btf_array *array = btf_array(t);
+ const struct btf_type *elem_type;
+ __u32 elem_type_id, elem_size;
+ bool ischar;
+
+ elem_type_id = array->type;
+ elem_size = btf__resolve_size(d->btf, elem_type_id);
+ elem_type = btf__type_by_id(d->btf, elem_type_id);
+
+ ischar = btf_is_int(elem_type) && elem_size == 1;
+
+ /* check all elements; if _any_ element is nonzero, all
+ * of array is displayed. We make an exception however
+ * for char arrays where the first element is 0; these
+ * are considered zeroed also, even if later elements are
+ * non-zero because the string is terminated.
+ */
+ for (i = 0; i < array->nelems; i++) {
+ if (i == 0 && ischar && *(char *)data == 0)
+ return -ENODATA;
+ err = btf_dump_type_data_check_zero(d, elem_type,
+ elem_type_id,
+ data +
+ (i * elem_size),
+ bits_offset, 0);
+ if (err != -ENODATA)
+ return err;
+ }
+ return -ENODATA;
+ }
+ case BTF_KIND_STRUCT:
+ case BTF_KIND_UNION: {
+ const struct btf_member *m = btf_members(t);
+ __u16 n = btf_vlen(t);
+
+ /* if any struct/union member is non-zero, the struct/union
+ * is considered non-zero and dumped.
+ */
+ for (i = 0; i < n; i++, m++) {
+ const struct btf_type *mtype;
+ __u32 moffset;
+ __u8 bit_sz;
+
+ mtype = btf__type_by_id(d->btf, m->type);
+ moffset = btf_member_bit_offset(t, i);
+
+ /* btf_int_bits() does not store member bitfield size;
+ * bitfield size needs to be stored here so int display
+ * of member can retrieve it.
+ */
+ bit_sz = btf_member_bitfield_size(t, i);
+ err = btf_dump_type_data_check_zero(d, mtype, m->type, data + moffset / 8,
+ moffset % 8, bit_sz);
+ if (err != ENODATA)
+ return err;
+ }
+ return -ENODATA;
+ }
+ case BTF_KIND_ENUM:
+ if (btf_dump_get_enum_value(t, data, id, &value))
+ return 0;
+ if (value == 0)
+ return -ENODATA;
+ return 0;
+ default:
+ return 0;
+ }
+}
+
+/* returns size of data dumped, or error. */
+static int btf_dump_dump_type_data(struct btf_dump *d,
+ const char *fname,
+ const struct btf_type *t,
+ __u32 id,
+ const void *data,
+ __u8 bits_offset,
+ __u8 bit_sz)
+{
+ int size, err;
+
+ size = btf_dump_type_data_check_overflow(d, t, id, data, bits_offset);
+ if (size < 0)
+ return size;
+ err = btf_dump_type_data_check_zero(d, t, id, data, bits_offset, bit_sz);
+ if (err) {
+ /* zeroed data is expected and not an error, so simply skip
+ * dumping such data. Record other errors however.
+ */
+ if (err == -ENODATA)
+ return size;
+ return err;
+ }
+ btf_dump_data_pfx(d);
+
+ if (!d->typed_dump->skip_names) {
+ if (fname && strlen(fname) > 0)
+ btf_dump_printf(d, ".%s = ", fname);
+ btf_dump_emit_type_cast(d, id, true);
+ }
+
+ t = skip_mods_and_typedefs(d->btf, id, NULL);
+ if (!t) {
+ pr_warn("unexpected error skipping mods/typedefs for id [%u]\n",
+ id);
+ return -EINVAL;
+ }
+
+ switch (BTF_INFO_KIND(t->info)) {
+ case BTF_KIND_UNKN:
+ case BTF_KIND_FWD:
+ case BTF_KIND_FUNC:
+ case BTF_KIND_FUNC_PROTO:
+ err = btf_dump_unsupported_data(d, t, id);
+ break;
+ case BTF_KIND_INT:
+ if (bit_sz)
+ err = btf_dump_bitfield_data(d, t, data, bits_offset, bit_sz);
+ else
+ err = btf_dump_int_data(d, t, id, data, bits_offset);
+ break;
+ case BTF_KIND_FLOAT:
+ err = btf_dump_float_data(d, t, id, data, bits_offset);
+ break;
+ case BTF_KIND_PTR:
+ err = btf_dump_ptr_data(d, t, id, data);
+ break;
+ case BTF_KIND_ARRAY:
+ err = btf_dump_array_data(d, t, id, data);
+ break;
+ case BTF_KIND_STRUCT:
+ case BTF_KIND_UNION:
+ err = btf_dump_struct_data(d, t, id, data);
+ break;
+ case BTF_KIND_ENUM:
+ /* handle bitfield and int enum values */
+ if (bit_sz) {
+ unsigned __int128 print_num;
+ __s64 enum_val;
+
+ print_num = btf_dump_bitfield_get_data(d, data, bits_offset, bit_sz);
+ enum_val = (__s64)print_num;
+ err = btf_dump_enum_data(d, t, id, &enum_val);
+ } else
+ err = btf_dump_enum_data(d, t, id, data);
+ break;
+ case BTF_KIND_VAR:
+ err = btf_dump_var_data(d, t, id, data);
+ break;
+ case BTF_KIND_DATASEC:
+ err = btf_dump_datasec_data(d, t, id, data);
+ break;
+ default:
+ pr_warn("unexpected kind [%u] for id [%u]\n",
+ BTF_INFO_KIND(t->info), id);
+ return -EINVAL;
+ }
+ if (err < 0)
+ return err;
+ return size;
+}
+
+int btf_dump__dump_type_data(struct btf_dump *d, __u32 id,
+ const void *data, size_t data_sz,
+ const struct btf_dump_type_data_opts *opts)
+{
+ const struct btf_type *t;
+ int ret;
+
+ if (!OPTS_VALID(opts, btf_dump_type_data_opts))
+ return libbpf_err(-EINVAL);
+
+ t = btf__type_by_id(d->btf, id);
+ if (!t)
+ return libbpf_err(-ENOENT);
+
+ d->typed_dump = calloc(1, sizeof(struct btf_dump_data));
+ if (!d->typed_dump)
+ return libbpf_err(-ENOMEM);
+
+ d->typed_dump->data_end = data + data_sz;
+ d->typed_dump->indent_lvl = OPTS_GET(opts, indent_level, 0);
+ /* default indent string is a tab */
+ if (!opts->indent_str)
+ d->typed_dump->indent_str[0] = '\t';
+ else {
+ if (strlen(opts->indent_str) >
+ sizeof(d->typed_dump->indent_str) - 1)
+ return libbpf_err(-EINVAL);
+ strncpy(d->typed_dump->indent_str, opts->indent_str,
+ sizeof(d->typed_dump->indent_str) - 1);
+ }
+
+ d->typed_dump->compact = OPTS_GET(opts, compact, false);
+ d->typed_dump->skip_names = OPTS_GET(opts, skip_names, false);
+ d->typed_dump->emit_zeroes = OPTS_GET(opts, emit_zeroes, false);
+
+ ret = btf_dump_dump_type_data(d, NULL, t, id, data, 0, 0);
+
+ free(d->typed_dump);
+
+ return libbpf_err(ret);
+}
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 944c99d..5bfc107 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -373,5 +373,6 @@ LIBBPF_0.5.0 {
bpf_map__initial_value;
bpf_map_lookup_and_delete_elem_flags;
bpf_object__gen_loader;
+ btf_dump__dump_type_data;
libbpf_set_strict_mode;
} LIBBPF_0.4.0;
--
1.8.3.1
