libbpf: Add BPF_PROG_BIND_MAP syscall and use it on .rodata section

The patch adds a simple wrapper bpf_prog_bind_map around the syscall.
When the libbpf tries to load a program, it will probe the kernel for
the support of this syscall and unconditionally bind .rodata section
to the program.

Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Link: https://lore.kernel.org/bpf/20200915234543.3220146-4-sdf@google.com

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 82b983ff6569..2baa1308737c 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -872,3 +872,19 @@ int bpf_enable_stats(enum bpf_stats_type type)
 
 	return sys_bpf(BPF_ENABLE_STATS, &attr, sizeof(attr));
 }
+
+int bpf_prog_bind_map(int prog_fd, int map_fd,
+		      const struct bpf_prog_bind_opts *opts)
+{
+	union bpf_attr attr;
+
+	if (!OPTS_VALID(opts, bpf_prog_bind_opts))
+		return -EINVAL;
+
+	memset(&attr, 0, sizeof(attr));
+	attr.prog_bind_map.prog_fd = prog_fd;
+	attr.prog_bind_map.map_fd = map_fd;
+	attr.prog_bind_map.flags = OPTS_GET(opts, flags, 0);
+
+	return sys_bpf(BPF_PROG_BIND_MAP, &attr, sizeof(attr));
+}