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-rw-r--r--tools/lib/bpf/btf.c1631
1 files changed, 1471 insertions, 160 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 6bdbc389b493..231b07203e3d 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */
+#include <byteswap.h>
#include <endian.h>
#include <stdio.h>
#include <stdlib.h>
@@ -21,26 +22,78 @@
#include "libbpf_internal.h"
#include "hashmap.h"
-/* make sure libbpf doesn't use kernel-only integer typedefs */
-#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
-
#define BTF_MAX_NR_TYPES 0x7fffffffU
#define BTF_MAX_STR_OFFSET 0x7fffffffU
static struct btf_type btf_void;
struct btf {
- union {
- struct btf_header *hdr;
- void *data;
- };
- struct btf_type **types;
- const char *strings;
- void *nohdr_data;
+ /* raw BTF data in native endianness */
+ void *raw_data;
+ /* raw BTF data in non-native endianness */
+ void *raw_data_swapped;
+ __u32 raw_size;
+ /* whether target endianness differs from the native one */
+ bool swapped_endian;
+
+ /*
+ * When BTF is loaded from an ELF or raw memory it is stored
+ * in a contiguous memory block. The hdr, type_data, and, strs_data
+ * point inside that memory region to their respective parts of BTF
+ * representation:
+ *
+ * +--------------------------------+
+ * | Header | Types | Strings |
+ * +--------------------------------+
+ * ^ ^ ^
+ * | | |
+ * hdr | |
+ * types_data-+ |
+ * strs_data------------+
+ *
+ * If BTF data is later modified, e.g., due to types added or
+ * removed, BTF deduplication performed, etc, this contiguous
+ * representation is broken up into three independently allocated
+ * memory regions to be able to modify them independently.
+ * raw_data is nulled out at that point, but can be later allocated
+ * and cached again if user calls btf__get_raw_data(), at which point
+ * raw_data will contain a contiguous copy of header, types, and
+ * strings:
+ *
+ * +----------+ +---------+ +-----------+
+ * | Header | | Types | | Strings |
+ * +----------+ +---------+ +-----------+
+ * ^ ^ ^
+ * | | |
+ * hdr | |
+ * types_data----+ |
+ * strs_data------------------+
+ *
+ * +----------+---------+-----------+
+ * | Header | Types | Strings |
+ * raw_data----->+----------+---------+-----------+
+ */
+ struct btf_header *hdr;
+
+ void *types_data;
+ size_t types_data_cap; /* used size stored in hdr->type_len */
+
+ /* type ID to `struct btf_type *` lookup index */
+ __u32 *type_offs;
+ size_t type_offs_cap;
__u32 nr_types;
- __u32 types_size;
- __u32 data_size;
+
+ void *strs_data;
+ size_t strs_data_cap; /* used size stored in hdr->str_len */
+
+ /* lookup index for each unique string in strings section */
+ struct hashmap *strs_hash;
+ /* whether strings are already deduplicated */
+ bool strs_deduped;
+ /* BTF object FD, if loaded into kernel */
int fd;
+
+ /* Pointer size (in bytes) for a target architecture of this BTF */
int ptr_sz;
};
@@ -49,60 +102,114 @@ static inline __u64 ptr_to_u64(const void *ptr)
return (__u64) (unsigned long) ptr;
}
-static int btf_add_type(struct btf *btf, struct btf_type *t)
+/* Ensure given dynamically allocated memory region pointed to by *data* with
+ * capacity of *cap_cnt* elements each taking *elem_sz* bytes has enough
+ * memory to accomodate *add_cnt* new elements, assuming *cur_cnt* elements
+ * are already used. At most *max_cnt* elements can be ever allocated.
+ * If necessary, memory is reallocated and all existing data is copied over,
+ * new pointer to the memory region is stored at *data, new memory region
+ * capacity (in number of elements) is stored in *cap.
+ * On success, memory pointer to the beginning of unused memory is returned.
+ * On error, NULL is returned.
+ */
+void *btf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
+ size_t cur_cnt, size_t max_cnt, size_t add_cnt)
{
- if (btf->types_size - btf->nr_types < 2) {
- struct btf_type **new_types;
- __u32 expand_by, new_size;
+ size_t new_cnt;
+ void *new_data;
- if (btf->types_size == BTF_MAX_NR_TYPES)
- return -E2BIG;
+ if (cur_cnt + add_cnt <= *cap_cnt)
+ return *data + cur_cnt * elem_sz;
- expand_by = max(btf->types_size >> 2, 16U);
- new_size = min(BTF_MAX_NR_TYPES, btf->types_size + expand_by);
+ /* requested more than the set limit */
+ if (cur_cnt + add_cnt > max_cnt)
+ return NULL;
- new_types = realloc(btf->types, sizeof(*new_types) * new_size);
- if (!new_types)
- return -ENOMEM;
+ new_cnt = *cap_cnt;
+ new_cnt += new_cnt / 4; /* expand by 25% */
+ if (new_cnt < 16) /* but at least 16 elements */
+ new_cnt = 16;
+ if (new_cnt > max_cnt) /* but not exceeding a set limit */
+ new_cnt = max_cnt;
+ if (new_cnt < cur_cnt + add_cnt) /* also ensure we have enough memory */
+ new_cnt = cur_cnt + add_cnt;
+
+ new_data = libbpf_reallocarray(*data, new_cnt, elem_sz);
+ if (!new_data)
+ return NULL;
- if (btf->nr_types == 0)
- new_types[0] = &btf_void;
+ /* zero out newly allocated portion of memory */
+ memset(new_data + (*cap_cnt) * elem_sz, 0, (new_cnt - *cap_cnt) * elem_sz);
- btf->types = new_types;
- btf->types_size = new_size;
- }
+ *data = new_data;
+ *cap_cnt = new_cnt;
+ return new_data + cur_cnt * elem_sz;
+}
- btf->types[++(btf->nr_types)] = t;
+/* Ensure given dynamically allocated memory region has enough allocated space
+ * to accommodate *need_cnt* elements of size *elem_sz* bytes each
+ */
+int btf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt)
+{
+ void *p;
+
+ if (need_cnt <= *cap_cnt)
+ return 0;
+ p = btf_add_mem(data, cap_cnt, elem_sz, *cap_cnt, SIZE_MAX, need_cnt - *cap_cnt);
+ if (!p)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static int btf_add_type_idx_entry(struct btf *btf, __u32 type_off)
+{
+ __u32 *p;
+
+ p = btf_add_mem((void **)&btf->type_offs, &btf->type_offs_cap, sizeof(__u32),
+ btf->nr_types + 1, BTF_MAX_NR_TYPES, 1);
+ if (!p)
+ return -ENOMEM;
+
+ *p = type_off;
return 0;
}
+static void btf_bswap_hdr(struct btf_header *h)
+{
+ h->magic = bswap_16(h->magic);
+ h->hdr_len = bswap_32(h->hdr_len);
+ h->type_off = bswap_32(h->type_off);
+ h->type_len = bswap_32(h->type_len);
+ h->str_off = bswap_32(h->str_off);
+ h->str_len = bswap_32(h->str_len);
+}
+
static int btf_parse_hdr(struct btf *btf)
{
- const struct btf_header *hdr = btf->hdr;
+ struct btf_header *hdr = btf->hdr;
__u32 meta_left;
- if (btf->data_size < sizeof(struct btf_header)) {
+ if (btf->raw_size < sizeof(struct btf_header)) {
pr_debug("BTF header not found\n");
return -EINVAL;
}
- if (hdr->magic != BTF_MAGIC) {
+ if (hdr->magic == bswap_16(BTF_MAGIC)) {
+ btf->swapped_endian = true;
+ if (bswap_32(hdr->hdr_len) != sizeof(struct btf_header)) {
+ pr_warn("Can't load BTF with non-native endianness due to unsupported header length %u\n",
+ bswap_32(hdr->hdr_len));
+ return -ENOTSUP;
+ }
+ btf_bswap_hdr(hdr);
+ } else if (hdr->magic != BTF_MAGIC) {
pr_debug("Invalid BTF magic:%x\n", hdr->magic);
return -EINVAL;
}
- if (hdr->version != BTF_VERSION) {
- pr_debug("Unsupported BTF version:%u\n", hdr->version);
- return -ENOTSUP;
- }
-
- if (hdr->flags) {
- pr_debug("Unsupported BTF flags:%x\n", hdr->flags);
- return -ENOTSUP;
- }
-
- meta_left = btf->data_size - sizeof(*hdr);
+ meta_left = btf->raw_size - sizeof(*hdr);
if (!meta_left) {
pr_debug("BTF has no data\n");
return -EINVAL;
@@ -128,15 +235,13 @@ static int btf_parse_hdr(struct btf *btf)
return -EINVAL;
}
- btf->nohdr_data = btf->hdr + 1;
-
return 0;
}
static int btf_parse_str_sec(struct btf *btf)
{
const struct btf_header *hdr = btf->hdr;
- const char *start = btf->nohdr_data + hdr->str_off;
+ const char *start = btf->strs_data;
const char *end = start + btf->hdr->str_len;
if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_STR_OFFSET ||
@@ -145,14 +250,12 @@ static int btf_parse_str_sec(struct btf *btf)
return -EINVAL;
}
- btf->strings = start;
-
return 0;
}
-static int btf_type_size(struct btf_type *t)
+static int btf_type_size(const struct btf_type *t)
{
- int base_size = sizeof(struct btf_type);
+ const int base_size = sizeof(struct btf_type);
__u16 vlen = btf_vlen(t);
switch (btf_kind(t)) {
@@ -185,25 +288,120 @@ static int btf_type_size(struct btf_type *t)
}
}
+static void btf_bswap_type_base(struct btf_type *t)
+{
+ t->name_off = bswap_32(t->name_off);
+ t->info = bswap_32(t->info);
+ t->type = bswap_32(t->type);
+}
+
+static int btf_bswap_type_rest(struct btf_type *t)
+{
+ struct btf_var_secinfo *v;
+ struct btf_member *m;
+ struct btf_array *a;
+ struct btf_param *p;
+ struct btf_enum *e;
+ __u16 vlen = btf_vlen(t);
+ int i;
+
+ switch (btf_kind(t)) {
+ case BTF_KIND_FWD:
+ case BTF_KIND_CONST:
+ case BTF_KIND_VOLATILE:
+ case BTF_KIND_RESTRICT:
+ case BTF_KIND_PTR:
+ case BTF_KIND_TYPEDEF:
+ case BTF_KIND_FUNC:
+ return 0;
+ case BTF_KIND_INT:
+ *(__u32 *)(t + 1) = bswap_32(*(__u32 *)(t + 1));
+ return 0;
+ case BTF_KIND_ENUM:
+ for (i = 0, e = btf_enum(t); i < vlen; i++, e++) {
+ e->name_off = bswap_32(e->name_off);
+ e->val = bswap_32(e->val);
+ }
+ return 0;
+ case BTF_KIND_ARRAY:
+ a = btf_array(t);
+ a->type = bswap_32(a->type);
+ a->index_type = bswap_32(a->index_type);
+ a->nelems = bswap_32(a->nelems);
+ return 0;
+ case BTF_KIND_STRUCT:
+ case BTF_KIND_UNION:
+ for (i = 0, m = btf_members(t); i < vlen; i++, m++) {
+ m->name_off = bswap_32(m->name_off);
+ m->type = bswap_32(m->type);
+ m->offset = bswap_32(m->offset);
+ }
+ return 0;
+ case BTF_KIND_FUNC_PROTO:
+ for (i = 0, p = btf_params(t); i < vlen; i++, p++) {
+ p->name_off = bswap_32(p->name_off);
+ p->type = bswap_32(p->type);
+ }
+ return 0;
+ case BTF_KIND_VAR:
+ btf_var(t)->linkage = bswap_32(btf_var(t)->linkage);
+ return 0;
+ case BTF_KIND_DATASEC:
+ for (i = 0, v = btf_var_secinfos(t); i < vlen; i++, v++) {
+ v->type = bswap_32(v->type);
+ v->offset = bswap_32(v->offset);
+ v->size = bswap_32(v->size);
+ }
+ return 0;
+ default:
+ pr_debug("Unsupported BTF_KIND:%u\n", btf_kind(t));
+ return -EINVAL;
+ }
+}
+
static int btf_parse_type_sec(struct btf *btf)
{
struct btf_header *hdr = btf->hdr;
- void *nohdr_data = btf->nohdr_data;
- void *next_type = nohdr_data + hdr->type_off;
- void *end_type = nohdr_data + hdr->str_off;
+ void *next_type = btf->types_data;
+ void *end_type = next_type + hdr->type_len;
+ int err, i = 0, type_size;
- while (next_type < end_type) {
- struct btf_type *t = next_type;
- int type_size;
- int err;
+ /* VOID (type_id == 0) is specially handled by btf__get_type_by_id(),
+ * so ensure we can never properly use its offset from index by
+ * setting it to a large value
+ */
+ err = btf_add_type_idx_entry(btf, UINT_MAX);
+ if (err)
+ return err;
+
+ while (next_type + sizeof(struct btf_type) <= end_type) {
+ i++;
+
+ if (btf->swapped_endian)
+ btf_bswap_type_base(next_type);
- type_size = btf_type_size(t);
+ type_size = btf_type_size(next_type);
if (type_size < 0)
return type_size;
- next_type += type_size;
- err = btf_add_type(btf, t);
+ if (next_type + type_size > end_type) {
+ pr_warn("BTF type [%d] is malformed\n", i);
+ return -EINVAL;
+ }
+
+ if (btf->swapped_endian && btf_bswap_type_rest(next_type))
+ return -EINVAL;
+
+ err = btf_add_type_idx_entry(btf, next_type - btf->types_data);
if (err)
return err;
+
+ next_type += type_size;
+ btf->nr_types++;
+ }
+
+ if (next_type != end_type) {
+ pr_warn("BTF types data is malformed\n");
+ return -EINVAL;
}
return 0;
@@ -214,12 +412,20 @@ __u32 btf__get_nr_types(const struct btf *btf)
return btf->nr_types;
}
+/* internal helper returning non-const pointer to a type */
+static struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id)
+{
+ if (type_id == 0)
+ return &btf_void;
+
+ return btf->types_data + btf->type_offs[type_id];
+}
+
const struct btf_type *btf__type_by_id(const struct btf *btf, __u32 type_id)
{
if (type_id > btf->nr_types)
return NULL;
-
- return btf->types[type_id];
+ return btf_type_by_id((struct btf *)btf, type_id);
}
static int determine_ptr_size(const struct btf *btf)
@@ -286,6 +492,38 @@ int btf__set_pointer_size(struct btf *btf, size_t ptr_sz)
return 0;
}
+static bool is_host_big_endian(void)
+{
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+ return false;
+#elif __BYTE_ORDER == __BIG_ENDIAN
+ return true;
+#else
+# error "Unrecognized __BYTE_ORDER__"
+#endif
+}
+
+enum btf_endianness btf__endianness(const struct btf *btf)
+{
+ if (is_host_big_endian())
+ return btf->swapped_endian ? BTF_LITTLE_ENDIAN : BTF_BIG_ENDIAN;
+ else
+ return btf->swapped_endian ? BTF_BIG_ENDIAN : BTF_LITTLE_ENDIAN;
+}
+
+int btf__set_endianness(struct btf *btf, enum btf_endianness endian)
+{
+ if (endian != BTF_LITTLE_ENDIAN && endian != BTF_BIG_ENDIAN)
+ return -EINVAL;
+
+ btf->swapped_endian = is_host_big_endian() != (endian == BTF_BIG_ENDIAN);
+ if (!btf->swapped_endian) {
+ free(btf->raw_data_swapped);
+ btf->raw_data_swapped = NULL;
+ }
+ return 0;
+}
+
static bool btf_type_is_void(const struct btf_type *t)
{
return t == &btf_void || btf_is_fwd(t);
@@ -417,7 +655,7 @@ __s32 btf__find_by_name(const struct btf *btf, const char *type_name)
return 0;
for (i = 1; i <= btf->nr_types; i++) {
- const struct btf_type *t = btf->types[i];
+ const struct btf_type *t = btf__type_by_id(btf, i);
const char *name = btf__name_by_offset(btf, t->name_off);
if (name && !strcmp(type_name, name))
@@ -436,7 +674,7 @@ __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
return 0;
for (i = 1; i <= btf->nr_types; i++) {
- const struct btf_type *t = btf->types[i];
+ const struct btf_type *t = btf__type_by_id(btf, i);
const char *name;
if (btf_kind(t) != kind)
@@ -449,6 +687,11 @@ __s32 btf__find_by_name_kind(const struct btf *btf, const char *type_name,
return -ENOENT;
}
+static bool btf_is_modifiable(const struct btf *btf)
+{
+ return (void *)btf->hdr != btf->raw_data;
+}
+
void btf__free(struct btf *btf)
{
if (IS_ERR_OR_NULL(btf))
@@ -457,11 +700,55 @@ void btf__free(struct btf *btf)
if (btf->fd >= 0)
close(btf->fd);
- free(btf->data);
- free(btf->types);
+ if (btf_is_modifiable(btf)) {
+ /* if BTF was modified after loading, it will have a split
+ * in-memory representation for header, types, and strings
+ * sections, so we need to free all of them individually. It
+ * might still have a cached contiguous raw data present,
+ * which will be unconditionally freed below.
+ */
+ free(btf->hdr);
+ free(btf->types_data);
+ free(btf->strs_data);
+ }
+ free(btf->raw_data);
+ free(btf->raw_data_swapped);
+ free(btf->type_offs);
free(btf);
}
+struct btf *btf__new_empty(void)
+{
+ struct btf *btf;
+
+ btf = calloc(1, sizeof(*btf));
+ if (!btf)
+ return ERR_PTR(-ENOMEM);
+
+ btf->fd = -1;
+ btf->ptr_sz = sizeof(void *);
+ btf->swapped_endian = false;
+
+ /* +1 for empty string at offset 0 */
+ btf->raw_size = sizeof(struct btf_header) + 1;
+ btf->raw_data = calloc(1, btf->raw_size);
+ if (!btf->raw_data) {
+ free(btf);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ btf->hdr = btf->raw_data;
+ btf->hdr->hdr_len = sizeof(struct btf_header);
+ btf->hdr->magic = BTF_MAGIC;
+ btf->hdr->version = BTF_VERSION;
+
+ btf->types_data = btf->raw_data + btf->hdr->hdr_len;
+ btf->strs_data = btf->raw_data + btf->hdr->hdr_len;
+ btf->hdr->str_len = 1; /* empty string at offset 0 */
+
+ return btf;
+}
+
struct btf *btf__new(const void *data, __u32 size)
{
struct btf *btf;
@@ -471,26 +758,28 @@ struct btf *btf__new(const void *data, __u32 size)
if (!btf)
return ERR_PTR(-ENOMEM);
- btf->fd = -1;
-
- btf->data = malloc(size);
- if (!btf->data) {
+ btf->raw_data = malloc(size);
+ if (!btf->raw_data) {
err = -ENOMEM;
goto done;
}
+ memcpy(btf->raw_data, data, size);
+ btf->raw_size = size;
- memcpy(btf->data, data, size);
- btf->data_size = size;
-
+ btf->hdr = btf->raw_data;
err = btf_parse_hdr(btf);
if (err)
goto done;
+ btf->strs_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->str_off;
+ btf->types_data = btf->raw_data + btf->hdr->hdr_len + btf->hdr->type_off;
+
err = btf_parse_str_sec(btf);
+ err = err ?: btf_parse_type_sec(btf);
if (err)
goto done;
- err = btf_parse_type_sec(btf);
+ btf->fd = -1;
done:
if (err) {
@@ -501,17 +790,6 @@ done:
return btf;
}
-static bool btf_check_endianness(const GElf_Ehdr *ehdr)
-{
-#if __BYTE_ORDER == __LITTLE_ENDIAN
- return ehdr->e_ident[EI_DATA] == ELFDATA2LSB;
-#elif __BYTE_ORDER == __BIG_ENDIAN
- return ehdr->e_ident[EI_DATA] == ELFDATA2MSB;
-#else
-# error "Unrecognized __BYTE_ORDER__"
-#endif
-}
-
struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext)
{
Elf_Data *btf_data = NULL, *btf_ext_data = NULL;
@@ -544,10 +822,6 @@ struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext)
pr_warn("failed to get EHDR from %s\n", path);
goto done;
}
- if (!btf_check_endianness(&ehdr)) {
- pr_warn("non-native ELF endianness is not supported\n");
- goto done;
- }
if (!elf_rawdata(elf_getscn(elf, ehdr.e_shstrndx), NULL)) {
pr_warn("failed to get e_shstrndx from %s\n", path);
goto done;
@@ -659,13 +933,7 @@ struct btf *btf__parse_raw(const char *path)
err = -EIO;
goto err_out;
}
- if (magic == __bswap_16(BTF_MAGIC)) {
- /* non-native endian raw BTF */
- pr_warn("non-native BTF endianness is not supported\n");
- err = -LIBBPF_ERRNO__ENDIAN;
- goto err_out;
- }
- if (magic != BTF_MAGIC) {
+ if (magic != BTF_MAGIC && magic != bswap_16(BTF_MAGIC)) {
/* definitely not a raw BTF */
err = -EPROTO;
goto err_out;
@@ -798,7 +1066,7 @@ int btf__finalize_data(struct bpf_object *obj, struct btf *btf)
__u32 i;
for (i = 1; i <= btf->nr_types; i++) {
- struct btf_type *t = btf->types[i];
+ struct btf_type *t = btf_type_by_id(btf, i);
/* Loader needs to fix up some of the things compiler
* couldn't get its hands on while emitting BTF. This
@@ -815,10 +1083,13 @@ int btf__finalize_data(struct bpf_object *obj, struct btf *btf)
return err;
}
+static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian);
+
int btf__load(struct btf *btf)
{
- __u32 log_buf_size = 0;
+ __u32 log_buf_size = 0, raw_size;
char *log_buf = NULL;
+ void *raw_data;
int err = 0;
if (btf->fd >= 0)
@@ -833,8 +1104,16 @@ retry_load:
*log_buf = 0;
}
- btf->fd = bpf_load_btf(btf->data, btf->data_size,
- log_buf, log_buf_size, false);
+ raw_data = btf_get_raw_data(btf, &raw_size, false);
+ if (!raw_data) {
+ err = -ENOMEM;
+ goto done;
+ }
+ /* cache native raw data representation */
+ btf->raw_size = raw_size;
+ btf->raw_data = raw_data;
+
+ btf->fd = bpf_load_btf(raw_data, raw_size, log_buf, log_buf_size, false);
if (btf->fd < 0) {
if (!log_buf || errno == ENOSPC) {
log_buf_size = max((__u32)BPF_LOG_BUF_SIZE,
@@ -865,20 +1144,88 @@ void btf__set_fd(struct btf *btf, int fd)
btf->fd = fd;
}
-const void *btf__get_raw_data(const struct btf *btf, __u32 *size)
+static void *btf_get_raw_data(const struct btf *btf, __u32 *size, bool swap_endian)
{
- *size = btf->data_size;
- return btf->data;
+ struct btf_header *hdr = btf->hdr;
+ struct btf_type *t;
+ void *data, *p;
+ __u32 data_sz;
+ int i;
+
+ data = swap_endian ? btf->raw_data_swapped : btf->raw_data;
+ if (data) {
+ *size = btf->raw_size;
+ return data;
+ }
+
+ data_sz = hdr->hdr_len + hdr->type_len + hdr->str_len;
+ data = calloc(1, data_sz);
+ if (!data)
+ return NULL;
+ p = data;
+
+ memcpy(p, hdr, hdr->hdr_len);
+ if (swap_endian)
+ btf_bswap_hdr(p);
+ p += hdr->hdr_len;
+
+ memcpy(p, btf->types_data, hdr->type_len);
+ if (swap_endian) {
+ for (i = 1; i <= btf->nr_types; i++) {
+ t = p + btf->type_offs[i];
+ /* btf_bswap_type_rest() relies on native t->info, so
+ * we swap base type info after we swapped all the
+ * additional information
+ */
+ if (btf_bswap_type_rest(t))
+ goto err_out;
+ btf_bswap_type_base(t);
+ }
+ }
+ p += hdr->type_len;
+
+ memcpy(p, btf->strs_data, hdr->str_len);
+ p += hdr->str_len;
+
+ *size = data_sz;
+ return data;
+err_out:
+ free(data);
+ return NULL;
}
-const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
+const void *btf__get_raw_data(const struct btf *btf_ro, __u32 *size)
+{
+ struct btf *btf = (struct btf *)btf_ro;
+ __u32 data_sz;
+ void *data;
+
+ data = btf_get_raw_data(btf, &data_sz, btf->swapped_endian);
+ if (!data)
+ return NULL;
+
+ btf->raw_size = data_sz;
+ if (btf->swapped_endian)
+ btf->raw_data_swapped = data;
+ else
+ btf->raw_data = data;
+ *size = data_sz;
+ return data;
+}
+
+const char *btf__str_by_offset(const struct btf *btf, __u32 offset)
{
if (offset < btf->hdr->str_len)
- return &btf->strings[offset];
+ return btf->strs_data + offset;
else
return NULL;
}
+const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
+{
+ return btf__str_by_offset(btf, offset);
+}
+
int btf__get_from_id(__u32 id, struct btf **btf)
{
struct bpf_btf_info btf_info = { 0 };
@@ -1014,6 +1361,970 @@ int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
return 0;
}
+static size_t strs_hash_fn(const void *key, void *ctx)
+{
+ struct btf *btf = ctx;
+ const char *str = btf->strs_data + (long)key;
+
+ return str_hash(str);
+}
+
+static bool strs_hash_equal_fn(const void *key1, const void *key2, void *ctx)
+{
+ struct btf *btf = ctx;
+ const char *str1 = btf->strs_data + (long)key1;
+ const char *str2 = btf->strs_data + (long)key2;
+
+ return strcmp(str1, str2) == 0;
+}
+
+static void btf_invalidate_raw_data(struct btf *btf)
+{
+ if (btf->raw_data) {
+ free(btf->raw_data);
+ btf->raw_data = NULL;
+ }
+ if (btf->raw_data_swapped) {
+ free(btf->raw_data_swapped);
+ btf->raw_data_swapped = NULL;
+ }
+}
+
+/* Ensure BTF is ready to be modified (by splitting into a three memory
+ * regions for header, types, and strings). Also invalidate cached
+ * raw_data, if any.
+ */
+static int btf_ensure_modifiable(struct btf *btf)
+{
+ void *hdr, *types, *strs, *strs_end, *s;
+ struct hashmap *hash = NULL;
+ long off;
+ int err;
+
+ if (btf_is_modifiable(btf)) {
+ /* any BTF modification invalidates raw_data */
+ btf_invalidate_raw_data(btf);
+ return 0;
+ }
+
+ /* split raw data into three memory regions */
+ hdr = malloc(btf->hdr->hdr_len);
+ types = malloc(btf->hdr->type_len);
+ strs = malloc(btf->hdr->str_len);
+ if (!hdr || !types || !strs)
+ goto err_out;
+
+ memcpy(hdr, btf->hdr, btf->hdr->hdr_len);
+ memcpy(types, btf->types_data, btf->hdr->type_len);
+ memcpy(strs, btf->strs_data, btf->hdr->str_len);
+
+ /* build lookup index for all strings */
+ hash = hashmap__new(strs_hash_fn, strs_hash_equal_fn, btf);
+ if (IS_ERR(hash)) {
+ err = PTR_ERR(hash);
+ hash = NULL;
+ goto err_out;
+ }
+
+ strs_end = strs + btf->hdr->str_len;
+ for (off = 0, s = strs; s < strs_end; off += strlen(s) + 1, s = strs + off) {
+ /* hashmap__add() returns EEXIST if string with the same
+ * content already is in the hash map
+ */
+ err = hashmap__add(hash, (void *)off, (void *)off);
+ if (err == -EEXIST)
+ continue; /* duplicate */
+ if (err)
+ goto err_out;
+ }
+
+ /* only when everything was successful, update internal state */
+ btf->hdr = hdr;
+ btf->types_data = types;
+ btf->types_data_cap = btf->hdr->type_len;
+ btf->strs_data = strs;
+ btf->strs_data_cap = btf->hdr->str_len;
+ btf->strs_hash = hash;
+ /* if BTF was created from scratch, all strings are guaranteed to be
+ * unique and deduplicated
+ */
+ btf->strs_deduped = btf->hdr->str_len <= 1;
+
+ /* invalidate raw_data representation */
+ btf_invalidate_raw_data(btf);
+
+ return 0;
+
+err_out:
+ hashmap__free(hash);
+ free(hdr);
+ free(types);
+ free(strs);
+ return -ENOMEM;
+}
+
+static void *btf_add_str_mem(struct btf *btf, size_t add_sz)
+{
+ return btf_add_mem(&btf->strs_data, &btf->strs_data_cap, 1,
+ btf->hdr->str_len, BTF_MAX_STR_OFFSET, add_sz);
+}
+
+/* Find an offset in BTF string section that corresponds to a given string *s*.
+ * Returns:
+ * - >0 offset into string section, if string is found;
+ * - -ENOENT, if string is not in the string section;
+ * - <0, on any other error.
+ */
+int btf__find_str(struct btf *btf, const char *s)
+{
+ long old_off, new_off, len;
+ void *p;
+
+ /* BTF needs to be in a modifiable state to build string lookup index */
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ /* see btf__add_str() for why we do this */
+ len = strlen(s) + 1;
+ p = btf_add_str_mem(btf, len);
+ if (!p)
+ return -ENOMEM;
+
+ new_off = btf->hdr->str_len;
+ memcpy(p, s, len);
+
+ if (hashmap__find(btf->strs_hash, (void *)new_off, (void **)&old_off))
+ return old_off;
+
+ return -ENOENT;
+}
+
+/* Add a string s to the BTF string section.
+ * Returns:
+ * - > 0 offset into string section, on success;
+ * - < 0, on error.
+ */
+int btf__add_str(struct btf *btf, const char *s)
+{
+ long old_off, new_off, len;
+ void *p;
+ int err;
+
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ /* Hashmap keys are always offsets within btf->strs_data, so to even
+ * look up some string from the "outside", we need to first append it
+ * at the end, so that it can be addressed with an offset. Luckily,
+ * until btf->hdr->str_len is incremented, that string is just a piece
+ * of garbage for the rest of BTF code, so no harm, no foul. On the
+ * other hand, if the string is unique, it's already appended and
+ * ready to be used, only a simple btf->hdr->str_len increment away.
+ */
+ len = strlen(s) + 1;
+ p = btf_add_str_mem(btf, len);
+ if (!p)
+ return -ENOMEM;
+
+ new_off = btf->hdr->str_len;
+ memcpy(p, s, len);
+
+ /* Now attempt to add the string, but only if the string with the same
+ * contents doesn't exist already (HASHMAP_ADD strategy). If such
+ * string exists, we'll get its offset in old_off (that's old_key).
+ */
+ err = hashmap__insert(btf->strs_hash, (void *)new_off, (void *)new_off,
+ HASHMAP_ADD, (const void **)&old_off, NULL);
+ if (err == -EEXIST)
+ return old_off; /* duplicated string, return existing offset */
+ if (err)
+ return err;
+
+ btf->hdr->str_len += len; /* new unique string, adjust data length */
+ return new_off;
+}
+
+static void *btf_add_type_mem(struct btf *btf, size_t add_sz)
+{
+ return btf_add_mem(&btf->types_data, &btf->types_data_cap, 1,
+ btf->hdr->type_len, UINT_MAX, add_sz);
+}
+
+static __u32 btf_type_info(int kind, int vlen, int kflag)
+{
+ return (kflag << 31) | (kind << 24) | vlen;
+}
+
+static void btf_type_inc_vlen(struct btf_type *t)
+{
+ t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t));
+}
+
+/*
+ * Append new BTF_KIND_INT type with:
+ * - *name* - non-empty, non-NULL type name;
+ * - *sz* - power-of-2 (1, 2, 4, ..) size of the type, in bytes;
+ * - encoding is a combination of BTF_INT_SIGNED, BTF_INT_CHAR, BTF_INT_BOOL.
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_int(struct btf *btf, const char *name, size_t byte_sz, int encoding)
+{
+ struct btf_type *t;
+ int sz, err, name_off;
+
+ /* non-empty name */
+ if (!name || !name[0])
+ return -EINVAL;
+ /* byte_sz must be power of 2 */
+ if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 16)
+ return -EINVAL;
+ if (encoding & ~(BTF_INT_SIGNED | BTF_INT_CHAR | BTF_INT_BOOL))
+ return -EINVAL;
+
+ /* deconstruct BTF, if necessary, and invalidate raw_data */
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type) + sizeof(int);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ /* if something goes wrong later, we might end up with an extra string,
+ * but that shouldn't be a problem, because BTF can't be constructed
+ * completely anyway and will most probably be just discarded
+ */
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+
+ t->name_off = name_off;
+ t->info = btf_type_info(BTF_KIND_INT, 0, 0);
+ t->size = byte_sz;
+ /* set INT info, we don't allow setting legacy bit offset/size */
+ *(__u32 *)(t + 1) = (encoding << 24) | (byte_sz * 8);
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/* it's completely legal to append BTF types with type IDs pointing forward to
+ * types that haven't been appended yet, so we only make sure that id looks
+ * sane, we can't guarantee that ID will always be valid
+ */
+static int validate_type_id(int id)
+{
+ if (id < 0 || id > BTF_MAX_NR_TYPES)
+ return -EINVAL;
+ return 0;
+}
+
+/* generic append function for PTR, TYPEDEF, CONST/VOLATILE/RESTRICT */
+static int btf_add_ref_kind(struct btf *btf, int kind, const char *name, int ref_type_id)
+{
+ struct btf_type *t;
+ int sz, name_off = 0, err;
+
+ if (validate_type_id(ref_type_id))
+ return -EINVAL;
+
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ if (name && name[0]) {
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+ }
+
+ t->name_off = name_off;
+ t->info = btf_type_info(kind, 0, 0);
+ t->type = ref_type_id;
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/*
+ * Append new BTF_KIND_PTR type with:
+ * - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_ptr(struct btf *btf, int ref_type_id)
+{
+ return btf_add_ref_kind(btf, BTF_KIND_PTR, NULL, ref_type_id);
+}
+
+/*
+ * Append new BTF_KIND_ARRAY type with:
+ * - *index_type_id* - type ID of the type describing array index;
+ * - *elem_type_id* - type ID of the type describing array element;
+ * - *nr_elems* - the size of the array;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_array(struct btf *btf, int index_type_id, int elem_type_id, __u32 nr_elems)
+{
+ struct btf_type *t;
+ struct btf_array *a;
+ int sz, err;
+
+ if (validate_type_id(index_type_id) || validate_type_id(elem_type_id))
+ return -EINVAL;
+
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type) + sizeof(struct btf_array);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ t->name_off = 0;
+ t->info = btf_type_info(BTF_KIND_ARRAY, 0, 0);
+ t->size = 0;
+
+ a = btf_array(t);
+ a->type = elem_type_id;
+ a->index_type = index_type_id;
+ a->nelems = nr_elems;
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/* generic STRUCT/UNION append function */
+static int btf_add_composite(struct btf *btf, int kind, const char *name, __u32 bytes_sz)
+{
+ struct btf_type *t;
+ int sz, err, name_off = 0;
+
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ if (name && name[0]) {
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+ }
+
+ /* start out with vlen=0 and no kflag; this will be adjusted when
+ * adding each member
+ */
+ t->name_off = name_off;
+ t->info = btf_type_info(kind, 0, 0);
+ t->size = bytes_sz;
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/*
+ * Append new BTF_KIND_STRUCT type with:
+ * - *name* - name of the struct, can be NULL or empty for anonymous structs;
+ * - *byte_sz* - size of the struct, in bytes;
+ *
+ * Struct initially has no fields in it. Fields can be added by
+ * btf__add_field() right after btf__add_struct() succeeds.
+ *
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_struct(struct btf *btf, const char *name, __u32 byte_sz)
+{
+ return btf_add_composite(btf, BTF_KIND_STRUCT, name, byte_sz);
+}
+
+/*
+ * Append new BTF_KIND_UNION type with:
+ * - *name* - name of the union, can be NULL or empty for anonymous union;
+ * - *byte_sz* - size of the union, in bytes;
+ *
+ * Union initially has no fields in it. Fields can be added by
+ * btf__add_field() right after btf__add_union() succeeds. All fields
+ * should have *bit_offset* of 0.
+ *
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_union(struct btf *btf, const char *name, __u32 byte_sz)
+{
+ return btf_add_composite(btf, BTF_KIND_UNION, name, byte_sz);
+}
+
+/*
+ * Append new field for the current STRUCT/UNION type with:
+ * - *name* - name of the field, can be NULL or empty for anonymous field;
+ * - *type_id* - type ID for the type describing field type;
+ * - *bit_offset* - bit offset of the start of the field within struct/union;
+ * - *bit_size* - bit size of a bitfield, 0 for non-bitfield fields;
+ * Returns:
+ * - 0, on success;
+ * - <0, on error.
+ */
+int btf__add_field(struct btf *btf, const char *name, int type_id,
+ __u32 bit_offset, __u32 bit_size)
+{
+ struct btf_type *t;
+ struct btf_member *m;
+ bool is_bitfield;
+ int sz, name_off = 0;
+
+ /* last type should be union/struct */
+ if (btf->nr_types == 0)
+ return -EINVAL;
+ t = btf_type_by_id(btf, btf->nr_types);
+ if (!btf_is_composite(t))
+ return -EINVAL;
+
+ if (validate_type_id(type_id))
+ return -EINVAL;
+ /* best-effort bit field offset/size enforcement */
+ is_bitfield = bit_size || (bit_offset % 8 != 0);
+ if (is_bitfield && (bit_size == 0 || bit_size > 255 || bit_offset > 0xffffff))
+ return -EINVAL;
+
+ /* only offset 0 is allowed for unions */
+ if (btf_is_union(t) && bit_offset)
+ return -EINVAL;
+
+ /* decompose and invalidate raw data */
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_member);
+ m = btf_add_type_mem(btf, sz);
+ if (!m)
+ return -ENOMEM;
+
+ if (name && name[0]) {
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+ }
+
+ m->name_off = name_off;
+ m->type = type_id;
+ m->offset = bit_offset | (bit_size << 24);
+
+ /* btf_add_type_mem can invalidate t pointer */
+ t = btf_type_by_id(btf, btf->nr_types);
+ /* update parent type's vlen and kflag */
+ t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, is_bitfield || btf_kflag(t));
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ return 0;
+}
+
+/*
+ * Append new BTF_KIND_ENUM type with:
+ * - *name* - name of the enum, can be NULL or empty for anonymous enums;
+ * - *byte_sz* - size of the enum, in bytes.
+ *
+ * Enum initially has no enum values in it (and corresponds to enum forward
+ * declaration). Enumerator values can be added by btf__add_enum_value()
+ * immediately after btf__add_enum() succeeds.
+ *
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_enum(struct btf *btf, const char *name, __u32 byte_sz)
+{
+ struct btf_type *t;
+ int sz, err, name_off = 0;
+
+ /* byte_sz must be power of 2 */
+ if (!byte_sz || (byte_sz & (byte_sz - 1)) || byte_sz > 8)
+ return -EINVAL;
+
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ if (name && name[0]) {
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+ }
+
+ /* start out with vlen=0; it will be adjusted when adding enum values */
+ t->name_off = name_off;
+ t->info = btf_type_info(BTF_KIND_ENUM, 0, 0);
+ t->size = byte_sz;
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/*
+ * Append new enum value for the current ENUM type with:
+ * - *name* - name of the enumerator value, can't be NULL or empty;
+ * - *value* - integer value corresponding to enum value *name*;
+ * Returns:
+ * - 0, on success;
+ * - <0, on error.
+ */
+int btf__add_enum_value(struct btf *btf, const char *name, __s64 value)
+{
+ struct btf_type *t;
+ struct btf_enum *v;
+ int sz, name_off;
+
+ /* last type should be BTF_KIND_ENUM */
+ if (btf->nr_types == 0)
+ return -EINVAL;
+ t = btf_type_by_id(btf, btf->nr_types);
+ if (!btf_is_enum(t))
+ return -EINVAL;
+
+ /* non-empty name */
+ if (!name || !name[0])
+ return -EINVAL;
+ if (value < INT_MIN || value > UINT_MAX)
+ return -E2BIG;
+
+ /* decompose and invalidate raw data */
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_enum);
+ v = btf_add_type_mem(btf, sz);
+ if (!v)
+ return -ENOMEM;
+
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+
+ v->name_off = name_off;
+ v->val = value;
+
+ /* update parent type's vlen */
+ t = btf_type_by_id(btf, btf->nr_types);
+ btf_type_inc_vlen(t);
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ return 0;
+}
+
+/*
+ * Append new BTF_KIND_FWD type with:
+ * - *name*, non-empty/non-NULL name;
+ * - *fwd_kind*, kind of forward declaration, one of BTF_FWD_STRUCT,
+ * BTF_FWD_UNION, or BTF_FWD_ENUM;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_fwd(struct btf *btf, const char *name, enum btf_fwd_kind fwd_kind)
+{
+ if (!name || !name[0])
+ return -EINVAL;
+
+ switch (fwd_kind) {
+ case BTF_FWD_STRUCT:
+ case BTF_FWD_UNION: {
+ struct btf_type *t;
+ int id;
+
+ id = btf_add_ref_kind(btf, BTF_KIND_FWD, name, 0);
+ if (id <= 0)
+ return id;
+ t = btf_type_by_id(btf, id);
+ t->info = btf_type_info(BTF_KIND_FWD, 0, fwd_kind == BTF_FWD_UNION);
+ return id;
+ }
+ case BTF_FWD_ENUM:
+ /* enum forward in BTF currently is just an enum with no enum
+ * values; we also assume a standard 4-byte size for it
+ */
+ return btf__add_enum(btf, name, sizeof(int));
+ default:
+ return -EINVAL;
+ }
+}
+
+/*
+ * Append new BTF_KING_TYPEDEF type with:
+ * - *name*, non-empty/non-NULL name;
+ * - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_typedef(struct btf *btf, const char *name, int ref_type_id)
+{
+ if (!name || !name[0])
+ return -EINVAL;
+
+ return btf_add_ref_kind(btf, BTF_KIND_TYPEDEF, name, ref_type_id);
+}
+
+/*
+ * Append new BTF_KIND_VOLATILE type with:
+ * - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_volatile(struct btf *btf, int ref_type_id)
+{
+ return btf_add_ref_kind(btf, BTF_KIND_VOLATILE, NULL, ref_type_id);
+}
+
+/*
+ * Append new BTF_KIND_CONST type with:
+ * - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_const(struct btf *btf, int ref_type_id)
+{
+ return btf_add_ref_kind(btf, BTF_KIND_CONST, NULL, ref_type_id);
+}
+
+/*
+ * Append new BTF_KIND_RESTRICT type with:
+ * - *ref_type_id* - referenced type ID, it might not exist yet;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_restrict(struct btf *btf, int ref_type_id)
+{
+ return btf_add_ref_kind(btf, BTF_KIND_RESTRICT, NULL, ref_type_id);
+}
+
+/*
+ * Append new BTF_KIND_FUNC type with:
+ * - *name*, non-empty/non-NULL name;
+ * - *proto_type_id* - FUNC_PROTO's type ID, it might not exist yet;
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_func(struct btf *btf, const char *name,
+ enum btf_func_linkage linkage, int proto_type_id)
+{
+ int id;
+
+ if (!name || !name[0])
+ return -EINVAL;
+ if (linkage != BTF_FUNC_STATIC && linkage != BTF_FUNC_GLOBAL &&
+ linkage != BTF_FUNC_EXTERN)
+ return -EINVAL;
+
+ id = btf_add_ref_kind(btf, BTF_KIND_FUNC, name, proto_type_id);
+ if (id > 0) {
+ struct btf_type *t = btf_type_by_id(btf, id);
+
+ t->info = btf_type_info(BTF_KIND_FUNC, linkage, 0);
+ }
+ return id;
+}
+
+/*
+ * Append new BTF_KIND_FUNC_PROTO with:
+ * - *ret_type_id* - type ID for return result of a function.
+ *
+ * Function prototype initially has no arguments, but they can be added by
+ * btf__add_func_param() one by one, immediately after
+ * btf__add_func_proto() succeeded.
+ *
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_func_proto(struct btf *btf, int ret_type_id)
+{
+ struct btf_type *t;
+ int sz, err;
+
+ if (validate_type_id(ret_type_id))
+ return -EINVAL;
+
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ /* start out with vlen=0; this will be adjusted when adding enum
+ * values, if necessary
+ */
+ t->name_off = 0;
+ t->info = btf_type_info(BTF_KIND_FUNC_PROTO, 0, 0);
+ t->type = ret_type_id;
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/*
+ * Append new function parameter for current FUNC_PROTO type with:
+ * - *name* - parameter name, can be NULL or empty;
+ * - *type_id* - type ID describing the type of the parameter.
+ * Returns:
+ * - 0, on success;
+ * - <0, on error.
+ */
+int btf__add_func_param(struct btf *btf, const char *name, int type_id)
+{
+ struct btf_type *t;
+ struct btf_param *p;
+ int sz, name_off = 0;
+
+ if (validate_type_id(type_id))
+ return -EINVAL;
+
+ /* last type should be BTF_KIND_FUNC_PROTO */
+ if (btf->nr_types == 0)
+ return -EINVAL;
+ t = btf_type_by_id(btf, btf->nr_types);
+ if (!btf_is_func_proto(t))
+ return -EINVAL;
+
+ /* decompose and invalidate raw data */
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_param);
+ p = btf_add_type_mem(btf, sz);
+ if (!p)
+ return -ENOMEM;
+
+ if (name && name[0]) {
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+ }
+
+ p->name_off = name_off;
+ p->type = type_id;
+
+ /* update parent type's vlen */
+ t = btf_type_by_id(btf, btf->nr_types);
+ btf_type_inc_vlen(t);
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ return 0;
+}
+
+/*
+ * Append new BTF_KIND_VAR type with:
+ * - *name* - non-empty/non-NULL name;
+ * - *linkage* - variable linkage, one of BTF_VAR_STATIC,
+ * BTF_VAR_GLOBAL_ALLOCATED, or BTF_VAR_GLOBAL_EXTERN;
+ * - *type_id* - type ID of the type describing the type of the variable.
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_var(struct btf *btf, const char *name, int linkage, int type_id)
+{
+ struct btf_type *t;
+ struct btf_var *v;
+ int sz, err, name_off;
+
+ /* non-empty name */
+ if (!name || !name[0])
+ return -EINVAL;
+ if (linkage != BTF_VAR_STATIC && linkage != BTF_VAR_GLOBAL_ALLOCATED &&
+ linkage != BTF_VAR_GLOBAL_EXTERN)
+ return -EINVAL;
+ if (validate_type_id(type_id))
+ return -EINVAL;
+
+ /* deconstruct BTF, if necessary, and invalidate raw_data */
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type) + sizeof(struct btf_var);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+
+ t->name_off = name_off;
+ t->info = btf_type_info(BTF_KIND_VAR, 0, 0);
+ t->type = type_id;
+
+ v = btf_var(t);
+ v->linkage = linkage;
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/*
+ * Append new BTF_KIND_DATASEC type with:
+ * - *name* - non-empty/non-NULL name;
+ * - *byte_sz* - data section size, in bytes.
+ *
+ * Data section is initially empty. Variables info can be added with
+ * btf__add_datasec_var_info() calls, after btf__add_datasec() succeeds.
+ *
+ * Returns:
+ * - >0, type ID of newly added BTF type;
+ * - <0, on error.
+ */
+int btf__add_datasec(struct btf *btf, const char *name, __u32 byte_sz)
+{
+ struct btf_type *t;
+ int sz, err, name_off;
+
+ /* non-empty name */
+ if (!name || !name[0])
+ return -EINVAL;
+
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_type);
+ t = btf_add_type_mem(btf, sz);
+ if (!t)
+ return -ENOMEM;
+
+ name_off = btf__add_str(btf, name);
+ if (name_off < 0)
+ return name_off;
+
+ /* start with vlen=0, which will be update as var_secinfos are added */
+ t->name_off = name_off;
+ t->info = btf_type_info(BTF_KIND_DATASEC, 0, 0);
+ t->size = byte_sz;
+
+ err = btf_add_type_idx_entry(btf, btf->hdr->type_len);
+ if (err)
+ return err;
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ btf->nr_types++;
+ return btf->nr_types;
+}
+
+/*
+ * Append new data section variable information entry for current DATASEC type:
+ * - *var_type_id* - type ID, describing type of the variable;
+ * - *offset* - variable offset within data section, in bytes;
+ * - *byte_sz* - variable size, in bytes.
+ *
+ * Returns:
+ * - 0, on success;
+ * - <0, on error.
+ */
+int btf__add_datasec_var_info(struct btf *btf, int var_type_id, __u32 offset, __u32 byte_sz)
+{
+ struct btf_type *t;
+ struct btf_var_secinfo *v;
+ int sz;
+
+ /* last type should be BTF_KIND_DATASEC */
+ if (btf->nr_types == 0)
+ return -EINVAL;
+ t = btf_type_by_id(btf, btf->nr_types);
+ if (!btf_is_datasec(t))
+ return -EINVAL;
+
+ if (validate_type_id(var_type_id))
+ return -EINVAL;
+
+ /* decompose and invalidate raw data */
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
+ sz = sizeof(struct btf_var_secinfo);
+ v = btf_add_type_mem(btf, sz);
+ if (!v)
+ return -ENOMEM;
+
+ v->type = var_type_id;
+ v->offset = offset;
+ v->size = byte_sz;
+
+ /* update parent type's vlen */
+ t = btf_type_by_id(btf, btf->nr_types);
+ btf_type_inc_vlen(t);
+
+ btf->hdr->type_len += sz;
+ btf->hdr->str_off += sz;
+ return 0;
+}
+
struct btf_ext_sec_setup_param {
__u32 off;
__u32 len;
@@ -1137,14 +2448,14 @@ static int btf_ext_setup_line_info(struct btf_ext *btf_ext)
return btf_ext_setup_info(btf_ext, &param);
}
-static int btf_ext_setup_field_reloc(struct btf_ext *btf_ext)
+static int btf_ext_setup_core_relos(struct btf_ext *btf_ext)
{
struct btf_ext_sec_setup_param param = {
- .off = btf_ext->hdr->field_reloc_off,
- .len = btf_ext->hdr->field_reloc_len,
- .min_rec_size = sizeof(struct bpf_field_reloc),
- .ext_info = &btf_ext->field_reloc_info,
- .desc = "field_reloc",
+ .off = btf_ext->hdr->core_relo_off,
+ .len = btf_ext->hdr->core_relo_len,
+ .min_rec_size = sizeof(struct bpf_core_relo),
+ .ext_info = &btf_ext->core_relo_info,
+ .desc = "core_relo",
};
return btf_ext_setup_info(btf_ext, &param);
@@ -1160,7 +2471,10 @@ static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
return -EINVAL;
}
- if (hdr->magic != BTF_MAGIC) {
+ if (hdr->magic == bswap_16(BTF_MAGIC)) {
+ pr_warn("BTF.ext in non-native endianness is not supported\n");
+ return -ENOTSUP;
+ } else if (hdr->magic != BTF_MAGIC) {
pr_debug("Invalid BTF.ext magic:%x\n", hdr->magic);
return -EINVAL;
}
@@ -1223,10 +2537,9 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
if (err)
goto done;
- if (btf_ext->hdr->hdr_len <
- offsetofend(struct btf_ext_header, field_reloc_len))
+ if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len))
goto done;
- err = btf_ext_setup_field_reloc(btf_ext);
+ err = btf_ext_setup_core_relos(btf_ext);
if (err)
goto done;
@@ -1481,6 +2794,9 @@ int btf__dedup(struct btf *btf, struct btf_ext *btf_ext,
return -EINVAL;
}
+ if (btf_ensure_modifiable(btf))
+ return -ENOMEM;
+
err = btf_dedup_strings(d);
if (err < 0) {
pr_debug("btf_dedup_strings failed:%d\n", err);
@@ -1581,7 +2897,7 @@ static int btf_dedup_hypot_map_add(struct btf_dedup *d,
__u32 *new_list;
d->hypot_cap += max((size_t)16, d->hypot_cap / 2);
- new_list = realloc(d->hypot_list, sizeof(__u32) * d->hypot_cap);
+ new_list = libbpf_reallocarray(d->hypot_list, d->hypot_cap, sizeof(__u32));
if (!new_list)
return -ENOMEM;
d->hypot_list = new_list;
@@ -1665,7 +2981,7 @@ static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext,
/* special BTF "void" type is made canonical immediately */
d->map[0] = 0;
for (i = 1; i <= btf->nr_types; i++) {
- struct btf_type *t = d->btf->types[i];
+ struct btf_type *t = btf_type_by_id(d->btf, i);
/* VAR and DATASEC are never deduped and are self-canonical */
if (btf_is_var(t) || btf_is_datasec(t))
@@ -1704,7 +3020,7 @@ static int btf_for_each_str_off(struct btf_dedup *d, str_off_fn_t fn, void *ctx)
struct btf_type *t;
for (i = 1; i <= d->btf->nr_types; i++) {
- t = d->btf->types[i];
+ t = btf_type_by_id(d->btf, i);
r = fn(&t->name_off, ctx);
if (r)
return r;
@@ -1858,8 +3174,7 @@ static int btf_str_remap_offset(__u32 *str_off_ptr, void *ctx)
*/
static int btf_dedup_strings(struct btf_dedup *d)
{
- const struct btf_header *hdr = d->btf->hdr;
- char *start = (char *)d->btf->nohdr_data + hdr->str_off;
+ char *start = d->btf->strs_data;
char *end = start + d->btf->hdr->str_len;
char *p = start, *tmp_strs = NULL;
struct btf_str_ptrs strs = {
@@ -1871,14 +3186,16 @@ static int btf_dedup_strings(struct btf_dedup *d)
int i, j, err = 0, grp_idx;
bool grp_used;
+ if (d->btf->strs_deduped)
+ return 0;
+
/* build index of all strings */
while (p < end) {
if (strs.cnt + 1 > strs.cap) {
struct btf_str_ptr *new_ptrs;
strs.cap += max(strs.cnt / 2, 16U);
- new_ptrs = realloc(strs.ptrs,
- sizeof(strs.ptrs[0]) * strs.cap);
+ new_ptrs = libbpf_reallocarray(strs.ptrs, strs.cap, sizeof(strs.ptrs[0]));
if (!new_ptrs) {
err = -ENOMEM;
goto done;
@@ -1964,6 +3281,7 @@ static int btf_dedup_strings(struct btf_dedup *d)
goto done;
d->btf->hdr->str_len = end - start;
+ d->btf->strs_deduped = true;
done:
free(tmp_strs);
@@ -2240,7 +3558,7 @@ static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2)
*/
static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
{
- struct btf_type *t = d->btf->types[type_id];
+ struct btf_type *t = btf_type_by_id(d->btf, type_id);
struct hashmap_entry *hash_entry;
struct btf_type *cand;
/* if we don't find equivalent type, then we are canonical */
@@ -2267,7 +3585,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
h = btf_hash_int(t);
for_each_dedup_cand(d, hash_entry, h) {
cand_id = (__u32)(long)hash_entry->value;
- cand = d->btf->types[cand_id];
+ cand = btf_type_by_id(d->btf, cand_id);
if (btf_equal_int(t, cand)) {
new_id = cand_id;
break;
@@ -2279,7 +3597,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
h = btf_hash_enum(t);
for_each_dedup_cand(d, hash_entry, h) {
cand_id = (__u32)(long)hash_entry->value;
- cand = d->btf->types[cand_id];
+ cand = btf_type_by_id(d->btf, cand_id);
if (btf_equal_enum(t, cand)) {
new_id = cand_id;
break;
@@ -2302,7 +3620,7 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
h = btf_hash_common(t);
for_each_dedup_cand(d, hash_entry, h) {
cand_id = (__u32)(long)hash_entry->value;
- cand = d->btf->types[cand_id];
+ cand = btf_type_by_id(d->btf, cand_id);
if (btf_equal_common(t, cand)) {
new_id = cand_id;
break;
@@ -2361,13 +3679,13 @@ static uint32_t resolve_fwd_id(struct btf_dedup *d, uint32_t type_id)
{
__u32 orig_type_id = type_id;
- if (!btf_is_fwd(d->btf->types[type_id]))
+ if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
return type_id;
while (is_type_mapped(d, type_id) && d->map[type_id] != type_id)
type_id = d->map[type_id];
- if (!btf_is_fwd(d->btf->types[type_id]))
+ if (!btf_is_fwd(btf__type_by_id(d->btf, type_id)))
return type_id;
return orig_type_id;
@@ -2495,8 +3813,8 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
if (btf_dedup_hypot_map_add(d, canon_id, cand_id))
return -ENOMEM;
- cand_type = d->btf->types[cand_id];
- canon_type = d->btf->types[canon_id];
+ cand_type = btf_type_by_id(d->btf, cand_id);
+ canon_type = btf_type_by_id(d->btf, canon_id);
cand_kind = btf_kind(cand_type);
canon_kind = btf_kind(canon_type);
@@ -2647,8 +3965,8 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d)
targ_type_id = d->hypot_map[cand_type_id];
t_id = resolve_type_id(d, targ_type_id);
c_id = resolve_type_id(d, cand_type_id);
- t_kind = btf_kind(d->btf->types[t_id]);
- c_kind = btf_kind(d->btf->types[c_id]);
+ t_kind = btf_kind(btf__type_by_id(d->btf, t_id));
+ c_kind = btf_kind(btf__type_by_id(d->btf, c_id));
/*
* Resolve FWD into STRUCT/UNION.
* It's ok to resolve FWD into STRUCT/UNION that's not yet
@@ -2716,7 +4034,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
if (d->map[type_id] <= BTF_MAX_NR_TYPES)
return 0;
- t = d->btf->types[type_id];
+ t = btf_type_by_id(d->btf, type_id);
kind = btf_kind(t);
if (kind != BTF_KIND_STRUCT && kind != BTF_KIND_UNION)
@@ -2737,7 +4055,7 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id)
* creating a loop (FWD -> STRUCT and STRUCT -> FWD), because
* FWD and compatible STRUCT/UNION are considered equivalent.
*/
- cand_type = d->btf->types[cand_id];
+ cand_type = btf_type_by_id(d->btf, cand_id);
if (!btf_shallow_equal_struct(t, cand_type))
continue;
@@ -2809,7 +4127,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
if (d->map[type_id] <= BTF_MAX_NR_TYPES)
return resolve_type_id(d, type_id);
- t = d->btf->types[type_id];
+ t = btf_type_by_id(d->btf, type_id);
d->map[type_id] = BTF_IN_PROGRESS_ID;
switch (btf_kind(t)) {
@@ -2827,7 +4145,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
h = btf_hash_common(t);
for_each_dedup_cand(d, hash_entry, h) {
cand_id = (__u32)(long)hash_entry->value;
- cand = d->btf->types[cand_id];
+ cand = btf_type_by_id(d->btf, cand_id);
if (btf_equal_common(t, cand)) {
new_id = cand_id;
break;
@@ -2851,7 +4169,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
h = btf_hash_array(t);
for_each_dedup_cand(d, hash_entry, h) {
cand_id = (__u32)(long)hash_entry->value;
- cand = d->btf->types[cand_id];
+ cand = btf_type_by_id(d->btf, cand_id);
if (btf_equal_array(t, cand)) {
new_id = cand_id;
break;
@@ -2883,7 +4201,7 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
h = btf_hash_fnproto(t);
for_each_dedup_cand(d, hash_entry, h) {
cand_id = (__u32)(long)hash_entry->value;
- cand = d->btf->types[cand_id];
+ cand = btf_type_by_id(d->btf, cand_id);
if (btf_equal_fnproto(t, cand)) {
new_id = cand_id;
break;
@@ -2931,9 +4249,9 @@ static int btf_dedup_ref_types(struct btf_dedup *d)
*/
static int btf_dedup_compact_types(struct btf_dedup *d)
{
- struct btf_type **new_types;
+ __u32 *new_offs;
__u32 next_type_id = 1;
- char *types_start, *p;
+ void *p;
int i, len;
/* we are going to reuse hypot_map to store compaction remapping */
@@ -2941,41 +4259,34 @@ static int btf_dedup_compact_types(struct btf_dedup *d)
for (i = 1; i <= d->btf->nr_types; i++)
d->hypot_map[i] = BTF_UNPROCESSED_ID;
- types_start = d->btf->nohdr_data + d->btf->hdr->type_off;
- p = types_start;
+ p = d->btf->types_data;
for (i = 1; i <= d->btf->nr_types; i++) {
if (d->map[i] != i)
continue;
- len = btf_type_size(d->btf->types[i]);
+ len = btf_type_size(btf__type_by_id(d->btf, i));
if (len < 0)
return len;
- memmove(p, d->btf->types[i], len);
+ memmove(p, btf__type_by_id(d->btf, i), len);
d->hypot_map[i] = next_type_id;
- d->btf->types[next_type_id] = (struct btf_type *)p;
+ d->btf->type_offs[next_type_id] = p - d->btf->types_data;
p += len;
next_type_id++;
}
/* shrink struct btf's internal types index and update btf_header */
d->btf->nr_types = next_type_id - 1;
- d->btf->types_size = d->btf->nr_types;
- d->btf->hdr->type_len = p - types_start;
- new_types = realloc(d->btf->types,
- (1 + d->btf->nr_types) * sizeof(struct btf_type *));
- if (!new_types)
+ d->btf->type_offs_cap = d->btf->nr_types + 1;
+ d->btf->hdr->type_len = p - d->btf->types_data;
+ new_offs = libbpf_reallocarray(d->btf->type_offs, d->btf->type_offs_cap,
+ sizeof(*new_offs));
+ if (!new_offs)
return -ENOMEM;
- d->btf->types = new_types;
-
- /* make sure string section follows type information without gaps */
- d->btf->hdr->str_off = p - (char *)d->btf->nohdr_data;
- memmove(p, d->btf->strings, d->btf->hdr->str_len);
- d->btf->strings = p;
- p += d->btf->hdr->str_len;
-
- d->btf->data_size = p - (char *)d->btf->data;
+ d->btf->type_offs = new_offs;
+ d->btf->hdr->str_off = d->btf->hdr->type_len;
+ d->btf->raw_size = d->btf->hdr->hdr_len + d->btf->hdr->type_len + d->btf->hdr->str_len;
return 0;
}
@@ -3008,7 +4319,7 @@ static int btf_dedup_remap_type_id(struct btf_dedup *d, __u32 type_id)
*/
static int btf_dedup_remap_type(struct btf_dedup *d, __u32 type_id)
{
- struct btf_type *t = d->btf->types[type_id];
+ struct btf_type *t = btf_type_by_id(d->btf, type_id);
int i, r;
switch (btf_kind(t)) {