Update the bpf_object_open_attr structure and corresponding code so that the
bpf_object__open_xattr function could be used to open objects from buffers as
well as from files. The reason for this change is that the existing
bpf_object__open_buffer function doesn't provide a way to specify neither the
needs_kver nor flags parameters to the internal call to __bpf_object__open
which makes it inconvenient for loading BPF objects which doesn't require a
kernel version.
Two new fields, obj_buf and obj_buf_sz, were added to the structure, and the
file field was union'ed with obj_name so that one can open an object like this:
struct bpf_object_open_attr attr = {
.obj_name = name,
.obj_buf = obj_buf,
.obj_buf_sz = obj_buf_sz,
.prog_type = BPF_PROG_TYPE_UNSPEC,
};
return bpf_object__open_xattr(&attr);
while still being able to use the file semantics:
struct bpf_object_open_attr attr = {
.file = path,
.prog_type = BPF_PROG_TYPE_UNSPEC,
};
return bpf_object__open_xattr(&attr);
Another thing to note is that since the commit c034a177d3c8 ("bpf: bpftool, add
flag to allow non-compat map definitions") which introduced a MAPS_RELAX_COMPAT
flag to load objects with non-compat map definitions, bpf_object__open_buffer
was called with this flag enabled (it was passed as the boolean true value in
flags argument to __bpf_object__open). The default behaviour for all open
functions is to clear this flag and this patch changes bpf_object__open_buffer
to clears this flag. It can be enabled, if needed, by opening an object from
buffer using __bpf_object__open_xattr.
Signed-off-by: Anton Protopopov <a.s.protopo...@gmail.com>
---
tools/lib/bpf/libbpf.c | 45 ++++++++++++++++++++++++++----------------
tools/lib/bpf/libbpf.h | 7 ++++++-
2 files changed, 34 insertions(+), 18 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 2233f919dd88..7c8054afd901 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3630,13 +3630,31 @@ __bpf_object__open(const char *path, void *obj_buf,
size_t obj_buf_sz,
struct bpf_object *__bpf_object__open_xattr(struct bpf_object_open_attr *attr,
int flags)
{
+ char tmp_name[64];
+
/* param validation */
- if (!attr->file)
+ if (!attr)
return NULL;
- pr_debug("loading %s\n", attr->file);
+ if (attr->obj_buf) {
+ if (attr->obj_buf_sz <= 0)
+ return NULL;
+ if (!attr->file) {
+ snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
+ (unsigned long)attr->obj_buf,
+ (unsigned long)attr->obj_buf_sz);
+ attr->obj_name = tmp_name;
+ }
+ pr_debug("loading object '%s' from buffer\n", attr->obj_name);
+ } else if (!attr->file) {
+ return NULL;
+ } else {
+ attr->obj_buf_sz = 0;
- return __bpf_object__open(attr->file, NULL, 0,
+ pr_debug("loading object file '%s'\n", attr->file);
+ }
+
+ return __bpf_object__open(attr->file, attr->obj_buf, attr->obj_buf_sz,
bpf_prog_type__needs_kver(attr->prog_type),
flags);
}
@@ -3660,21 +3678,14 @@ struct bpf_object *bpf_object__open_buffer(void
*obj_buf,
size_t obj_buf_sz,
const char *name)
{
- char tmp_name[64];
-
- /* param validation */
- if (!obj_buf || obj_buf_sz <= 0)
- return NULL;
-
- if (!name) {
- snprintf(tmp_name, sizeof(tmp_name), "%lx-%lx",
- (unsigned long)obj_buf,
- (unsigned long)obj_buf_sz);
- name = tmp_name;
- }
- pr_debug("loading object '%s' from buffer\n", name);
+ struct bpf_object_open_attr attr = {
+ .obj_name = name,
+ .obj_buf = obj_buf,
+ .obj_buf_sz = obj_buf_sz,
+ .prog_type = BPF_PROG_TYPE_UNSPEC,
+ };
- return __bpf_object__open(name, obj_buf, obj_buf_sz, true, true);
+ return bpf_object__open_xattr(&attr);
}
int bpf_object__unload(struct bpf_object *obj)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index e8f70977d137..634f278578dd 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -63,8 +63,13 @@ LIBBPF_API libbpf_print_fn_t
libbpf_set_print(libbpf_print_fn_t fn);
struct bpf_object;
struct bpf_object_open_attr {
- const char *file;
+ union {
+ const char *file;
+ const char *obj_name;
+ };
enum bpf_prog_type prog_type;
+ void *obj_buf;
+ size_t obj_buf_sz;
};
LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
--
2.19.1
