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Message-ID: <20181012185526.2380717-2-yhs@fb.com>
Date: Fri, 12 Oct 2018 11:55:24 -0700
From: Yonghong Song <yhs@...com>
To: <ast@...com>, <kafai@...com>, <daniel@...earbox.net>,
<netdev@...r.kernel.org>
CC: <kernel-team@...com>
Subject: [PATCH bpf-next 11/13] tools/bpf: refactor to implement btf_get_from_id() in lib/bpf
The function get_btf() is implemented in tools/bpf/bpftool/map.c
to get a btf structure given a map_info. This patch
refactored this function to be function btf_get_from_id()
in tools/lib/bpf so that it can be used later.
Signed-off-by: Yonghong Song <yhs@...com>
---
tools/bpf/bpftool/map.c | 68 ++--------------------------------------
tools/lib/bpf/btf.c | 69 +++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/btf.h | 1 +
3 files changed, 72 insertions(+), 66 deletions(-)
diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 9f5de48f8a99..33c7dc8ddd86 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -203,70 +203,6 @@ static int do_dump_btf(const struct btf_dumper *d,
return ret;
}
-static int get_btf(struct bpf_map_info *map_info, struct btf **btf)
-{
- struct bpf_btf_info btf_info = { 0 };
- __u32 len = sizeof(btf_info);
- __u32 last_size;
- int btf_fd;
- void *ptr;
- int err;
-
- err = 0;
- *btf = NULL;
- btf_fd = bpf_btf_get_fd_by_id(map_info->btf_id);
- if (btf_fd < 0)
- return 0;
-
- /* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
- * let's start with a sane default - 4KiB here - and resize it only if
- * bpf_obj_get_info_by_fd() needs a bigger buffer.
- */
- btf_info.btf_size = 4096;
- last_size = btf_info.btf_size;
- ptr = malloc(last_size);
- if (!ptr) {
- err = -ENOMEM;
- goto exit_free;
- }
-
- bzero(ptr, last_size);
- btf_info.btf = ptr_to_u64(ptr);
- err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
-
- if (!err && btf_info.btf_size > last_size) {
- void *temp_ptr;
-
- last_size = btf_info.btf_size;
- temp_ptr = realloc(ptr, last_size);
- if (!temp_ptr) {
- err = -ENOMEM;
- goto exit_free;
- }
- ptr = temp_ptr;
- bzero(ptr, last_size);
- btf_info.btf = ptr_to_u64(ptr);
- err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
- }
-
- if (err || btf_info.btf_size > last_size) {
- err = errno;
- goto exit_free;
- }
-
- *btf = btf__new((__u8 *)btf_info.btf, btf_info.btf_size, NULL);
- if (IS_ERR(*btf)) {
- err = PTR_ERR(*btf);
- *btf = NULL;
- }
-
-exit_free:
- close(btf_fd);
- free(ptr);
-
- return err;
-}
-
static json_writer_t *get_btf_writer(void)
{
json_writer_t *jw = jsonw_new(stdout);
@@ -753,7 +689,7 @@ static int do_dump(int argc, char **argv)
prev_key = NULL;
- err = get_btf(&info, &btf);
+ err = btf_get_from_id(info.btf_id, &btf);
if (err) {
p_err("failed to get btf");
goto exit_free;
@@ -897,7 +833,7 @@ static int do_lookup(int argc, char **argv)
}
/* here means bpf_map_lookup_elem() succeeded */
- err = get_btf(&info, &btf);
+ err = btf_get_from_id(info.btf_id, &btf);
if (err) {
p_err("failed to get btf");
goto exit_free;
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 4748e0bacd2b..ab654628e966 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -42,6 +42,11 @@ struct btf_ext {
__u32 func_info_len;
};
+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)
{
if (btf->types_size - btf->nr_types < 2) {
@@ -403,6 +408,70 @@ const char *btf__name_by_offset(const struct btf *btf, __u32 offset)
return NULL;
}
+int btf_get_from_id(__u32 id, struct btf **btf)
+{
+ struct bpf_btf_info btf_info = { 0 };
+ __u32 len = sizeof(btf_info);
+ __u32 last_size;
+ int btf_fd;
+ void *ptr;
+ int err;
+
+ err = 0;
+ *btf = NULL;
+ btf_fd = bpf_btf_get_fd_by_id(id);
+ if (btf_fd < 0)
+ return 0;
+
+ /* we won't know btf_size until we call bpf_obj_get_info_by_fd(). so
+ * let's start with a sane default - 4KiB here - and resize it only if
+ * bpf_obj_get_info_by_fd() needs a bigger buffer.
+ */
+ btf_info.btf_size = 4096;
+ last_size = btf_info.btf_size;
+ ptr = malloc(last_size);
+ if (!ptr) {
+ err = -ENOMEM;
+ goto exit_free;
+ }
+
+ bzero(ptr, last_size);
+ btf_info.btf = ptr_to_u64(ptr);
+ err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
+
+ if (!err && btf_info.btf_size > last_size) {
+ void *temp_ptr;
+
+ last_size = btf_info.btf_size;
+ temp_ptr = realloc(ptr, last_size);
+ if (!temp_ptr) {
+ err = -ENOMEM;
+ goto exit_free;
+ }
+ ptr = temp_ptr;
+ bzero(ptr, last_size);
+ btf_info.btf = ptr_to_u64(ptr);
+ err = bpf_obj_get_info_by_fd(btf_fd, &btf_info, &len);
+ }
+
+ if (err || btf_info.btf_size > last_size) {
+ err = errno;
+ goto exit_free;
+ }
+
+ *btf = btf__new((__u8 *)btf_info.btf, btf_info.btf_size, NULL);
+ if (IS_ERR(*btf)) {
+ err = PTR_ERR(*btf);
+ *btf = NULL;
+ }
+
+exit_free:
+ close(btf_fd);
+ free(ptr);
+
+ return err;
+}
+
static int btf_ext_validate_func_info(const struct btf_sec_func_info *sinfo,
__u32 size, btf_print_fn_t err_log)
{
diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 2bbcc9e41cf5..51e63da844e6 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -44,6 +44,7 @@ __s64 btf__resolve_size(const struct btf *btf, __u32 type_id);
int btf__resolve_type(const struct btf *btf, __u32 type_id);
int btf__fd(const struct btf *btf);
const char *btf__name_by_offset(const struct btf *btf, __u32 offset);
+int btf_get_from_id(__u32 id, struct btf **btf);
struct btf_ext *btf_ext__new(__u8 *data, __u32 size, btf_print_fn_t err_log);
void btf_ext__free(struct btf_ext *btf_ext);
--
2.17.1
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