BpfSyscallWrappers: add queryProgram()
Test: TreeHugger
Bug: 292156770
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I0f77220a6c4b13efb5630d7a5ade1db39c59901e
diff --git a/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h b/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h
index 13f7cb3..9995cb9 100644
--- a/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h
+++ b/staticlibs/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h
@@ -44,6 +44,11 @@
return syscall(__NR_bpf, cmd, &attr, sizeof(attr));
}
+// this version is meant for use with cmd's which mutate the argument
+inline int bpf(enum bpf_cmd cmd, bpf_attr *attr) {
+ return syscall(__NR_bpf, cmd, attr, sizeof(*attr));
+}
+
inline int createMap(bpf_map_type map_type, uint32_t key_size, uint32_t value_size,
uint32_t max_entries, uint32_t map_flags) {
return bpf(BPF_MAP_CREATE, {
@@ -160,6 +165,27 @@
});
}
+inline int queryProgram(const BPF_FD_TYPE cg_fd,
+ enum bpf_attach_type attach_type,
+ __u32 query_flags = 0,
+ __u32 attach_flags = 0) {
+ int prog_id = -1; // equivalent to an array of one integer.
+ bpf_attr arg = {
+ .query = {
+ .target_fd = BPF_FD_TO_U32(cg_fd),
+ .attach_type = attach_type,
+ .query_flags = query_flags,
+ .attach_flags = attach_flags,
+ .prog_ids = ptr_to_u64(&prog_id), // pointer to output array
+ .prog_cnt = 1, // in: space - nr of ints in the array, out: used
+ }
+ };
+ int v = bpf(BPF_PROG_QUERY, &arg);
+ if (v) return v; // error case
+ if (!arg.query.prog_cnt) return 0; // no program, kernel never returns zero id
+ return prog_id; // return actual id
+}
+
inline int detachSingleProgram(bpf_attach_type type, const BPF_FD_TYPE prog_fd,
const BPF_FD_TYPE cg_fd) {
return bpf(BPF_PROG_DETACH, {