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Date: Thu, 7 Feb 2019 18:55:54 -0800
From: Andrii Nakryiko <andriin@...com>
To: <alexei.starovoitov@...il.com>, <andrii.nakryiko@...il.com>,
<songliubraving@...com>, <yhs@...com>, <ast@...com>,
<kafai@...com>, <netdev@...r.kernel.org>, <kernel-team@...com>,
<daniel@...earbox.net>
CC: Andrii Nakryiko <andriin@...com>
Subject: [PATCH v3 bpf-next 3/4] btf: expose API to work with raw btf_ext data
This patch changes struct btf_ext to retain original data in sequential
block of memory, which makes it possible to expose
btf_ext__get_raw_data() interface, that's similar to
btf__get_raw_data(), allowing users of libbpf to get access to raw
representation of .BTF.ext section.
Signed-off-by: Andrii Nakryiko <andriin@...com>
---
tools/lib/bpf/btf.c | 85 +++++++++++++++++++++-------------------
tools/lib/bpf/btf.h | 2 +
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 47 insertions(+), 41 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 8730f6c3be9e..c87cc3d71b9f 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -41,9 +41,8 @@ struct btf {
struct btf_ext_info {
/*
- * info points to a deep copy of the individual info section
- * (e.g. func_info and line_info) from the .BTF.ext.
- * It does not include the __u32 rec_size.
+ * info points to the individual info section (e.g. func_info and
+ * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
*/
void *info;
__u32 rec_size;
@@ -51,8 +50,13 @@ struct btf_ext_info {
};
struct btf_ext {
+ union {
+ struct btf_ext_header *hdr;
+ void *data;
+ };
struct btf_ext_info func_info;
struct btf_ext_info line_info;
+ __u32 data_size;
};
struct btf_ext_info_sec {
@@ -603,19 +607,13 @@ struct btf_ext_sec_copy_param {
};
static int btf_ext_copy_info(struct btf_ext *btf_ext,
- __u8 *data, __u32 data_size,
struct btf_ext_sec_copy_param *ext_sec)
{
- const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
const struct btf_ext_info_sec *sinfo;
struct btf_ext_info *ext_info;
__u32 info_left, record_size;
/* The start of the info sec (including the __u32 record_size). */
- const void *info;
-
- /* data and data_size do not include btf_ext_header from now on */
- data = data + hdr->hdr_len;
- data_size -= hdr->hdr_len;
+ void *info;
if (ext_sec->off & 0x03) {
pr_debug(".BTF.ext %s section is not aligned to 4 bytes\n",
@@ -623,16 +621,15 @@ static int btf_ext_copy_info(struct btf_ext *btf_ext,
return -EINVAL;
}
- if (data_size < ext_sec->off ||
- ext_sec->len > data_size - ext_sec->off) {
+ info = btf_ext->data + btf_ext->hdr->hdr_len + ext_sec->off;
+ info_left = ext_sec->len;
+
+ if (btf_ext->data + btf_ext->data_size < info + ext_sec->len) {
pr_debug("%s section (off:%u len:%u) is beyond the end of the ELF section .BTF.ext\n",
- ext_sec->desc, ext_sec->off, ext_sec->len);
+ ext_sec->desc, ext_sec->off, ext_sec->len);
return -EINVAL;
}
- info = data + ext_sec->off;
- info_left = ext_sec->len;
-
/* At least a record size */
if (info_left < sizeof(__u32)) {
pr_debug(".BTF.ext %s record size not found\n", ext_sec->desc);
@@ -644,7 +641,7 @@ static int btf_ext_copy_info(struct btf_ext *btf_ext,
if (record_size < ext_sec->min_rec_size ||
record_size & 0x03) {
pr_debug("%s section in .BTF.ext has invalid record size %u\n",
- ext_sec->desc, record_size);
+ ext_sec->desc, record_size);
return -EINVAL;
}
@@ -690,42 +687,35 @@ static int btf_ext_copy_info(struct btf_ext *btf_ext,
ext_info = ext_sec->ext_info;
ext_info->len = ext_sec->len - sizeof(__u32);
ext_info->rec_size = record_size;
- ext_info->info = malloc(ext_info->len);
- if (!ext_info->info)
- return -ENOMEM;
- memcpy(ext_info->info, info + sizeof(__u32), ext_info->len);
+ ext_info->info = info + sizeof(__u32);
return 0;
}
-static int btf_ext_copy_func_info(struct btf_ext *btf_ext,
- __u8 *data, __u32 data_size)
+static int btf_ext_copy_func_info(struct btf_ext *btf_ext)
{
- const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
struct btf_ext_sec_copy_param param = {
- .off = hdr->func_info_off,
- .len = hdr->func_info_len,
+ .off = btf_ext->hdr->func_info_off,
+ .len = btf_ext->hdr->func_info_len,
.min_rec_size = sizeof(struct bpf_func_info_min),
.ext_info = &btf_ext->func_info,
.desc = "func_info"
};
- return btf_ext_copy_info(btf_ext, data, data_size, ¶m);
+ return btf_ext_copy_info(btf_ext, ¶m);
}
-static int btf_ext_copy_line_info(struct btf_ext *btf_ext,
- __u8 *data, __u32 data_size)
+static int btf_ext_copy_line_info(struct btf_ext *btf_ext)
{
- const struct btf_ext_header *hdr = (struct btf_ext_header *)data;
struct btf_ext_sec_copy_param param = {
- .off = hdr->line_info_off,
- .len = hdr->line_info_len,
+ .off = btf_ext->hdr->line_info_off,
+ .len = btf_ext->hdr->line_info_len,
.min_rec_size = sizeof(struct bpf_line_info_min),
.ext_info = &btf_ext->line_info,
.desc = "line_info",
};
- return btf_ext_copy_info(btf_ext, data, data_size, ¶m);
+ return btf_ext_copy_info(btf_ext, ¶m);
}
static int btf_ext_parse_hdr(__u8 *data, __u32 data_size)
@@ -765,9 +755,7 @@ void btf_ext__free(struct btf_ext *btf_ext)
{
if (!btf_ext)
return;
-
- free(btf_ext->func_info.info);
- free(btf_ext->line_info.info);
+ free(btf_ext->data);
free(btf_ext);
}
@@ -784,13 +772,23 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
if (!btf_ext)
return ERR_PTR(-ENOMEM);
- err = btf_ext_copy_func_info(btf_ext, data, size);
- if (err) {
- btf_ext__free(btf_ext);
- return ERR_PTR(err);
+ btf_ext->data_size = size;
+ btf_ext->data = malloc(size);
+ if (!btf_ext->data) {
+ err = -ENOMEM;
+ goto done;
}
+ memcpy(btf_ext->data, data, size);
+
+ err = btf_ext_copy_func_info(btf_ext);
+ if (err)
+ goto done;
+
+ err = btf_ext_copy_line_info(btf_ext);
+ if (err)
+ goto done;
- err = btf_ext_copy_line_info(btf_ext, data, size);
+done:
if (err) {
btf_ext__free(btf_ext);
return ERR_PTR(err);
@@ -799,6 +797,11 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size)
return btf_ext;
}
+const void *btf_ext__get_raw_data(const struct btf_ext* btf_ext, __u32 *size) {
+ *size = btf_ext->data_size;
+ return btf_ext->data;
+}
+
static int btf_ext_reloc_info(const struct btf *btf,
const struct btf_ext_info *ext_info,
const char *sec_name, __u32 insns_cnt,
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index d6c0a5576fdc..ad9f648260c2 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -78,6 +78,8 @@ LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name,
LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size);
LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext);
+LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext* btf_ext,
+ __u32 *size);
LIBBPF_API int btf_ext__reloc_func_info(const struct btf *btf,
const struct btf_ext *btf_ext,
const char *sec_name, __u32 insns_cnt,
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 9e10467f8cbb..eb78c7c261d9 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -141,6 +141,7 @@ LIBBPF_0.0.2 {
btf__load;
btf_ext__free;
btf_ext__func_info_rec_size;
+ btf_ext__get_raw_data;
btf_ext__line_info_rec_size;
btf_ext__new;
btf_ext__reloc_func_info;
--
2.17.1
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