[PATCH v2 2/9] libbpf: Introduce bpf_obj_get_flags()

From: Roberto Sassu
Date: Thu Jun 02 2022 - 10:38:23 EST


Introduce the bpf_obj_get_flags() function, so that it is possible to
specify the needed permissions for obtaining a file descriptor from a
pinned object.

Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
---
tools/lib/bpf/bpf.c | 8 +++++++-
tools/lib/bpf/bpf.h | 1 +
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 33bac2006043..a5fc40f6ce13 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -670,18 +670,24 @@ int bpf_obj_pin(int fd, const char *pathname)
return libbpf_err_errno(ret);
}

-int bpf_obj_get(const char *pathname)
+int bpf_obj_get_flags(const char *pathname, __u32 flags)
{
union bpf_attr attr;
int fd;

memset(&attr, 0, sizeof(attr));
attr.pathname = ptr_to_u64((void *)pathname);
+ attr.file_flags = flags;

fd = sys_bpf_fd(BPF_OBJ_GET, &attr, sizeof(attr));
return libbpf_err_errno(fd);
}

+int bpf_obj_get(const char *pathname)
+{
+ return bpf_obj_get_flags(pathname, 0);
+}
+
int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
unsigned int flags)
{
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 20e4c852362d..6d0ceb2e90c4 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -339,6 +339,7 @@ LIBBPF_API int bpf_map_update_batch(int fd, const void *keys, const void *values
const struct bpf_map_batch_opts *opts);

LIBBPF_API int bpf_obj_pin(int fd, const char *pathname);
+LIBBPF_API int bpf_obj_get_flags(const char *pathname, __u32 flags);
LIBBPF_API int bpf_obj_get(const char *pathname);

struct bpf_prog_attach_opts {
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 019278e66836..6c3ace12b27b 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -467,6 +467,7 @@ LIBBPF_1.0.0 {
libbpf_bpf_map_type_str;
libbpf_bpf_prog_type_str;
bpf_map_get_fd_by_id_flags;
+ bpf_obj_get_flags;

local: *;
};
--
2.25.1