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@oracle.com --- 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;