add map_ids field to bpf_prog_get_info_by_fd

Add an optional field (map_ids) to the syscall, this allows a pointer to
a buffer to be filled with the map_ids in use by the program.

Signed-off-by: Andrew Stoycos <astoycos@redhat.com>

aya/src/programs/extension.rs

@@ -151,10 +151,11 @@ impl Extension {
 /// with the name `func_name` within that BTF object.
 fn get_btf_info(prog_fd: i32, func_name: &str) -> Result<(RawFd, u32), ProgramError> {
     // retrieve program information
-    let info =
+    let info = sys::bpf_prog_get_info_by_fd(prog_fd, &[]).map_err(|io_error| {
-        sys::bpf_prog_get_info_by_fd(prog_fd).map_err(|io_error| ProgramError::SyscallError {
+        ProgramError::SyscallError {
             call: "bpf_prog_get_info_by_fd",
             io_error,
+        }
     })?;
 
     // btf_id refers to the ID of the program btf that was loaded with bpf(BPF_BTF_LOAD)

aya/src/programs/lirc_mode2.rs

@@ -132,7 +132,7 @@ impl LircLink {
 
     /// Get ProgramInfo from this link
     pub fn info(&self) -> Result<ProgramInfo, ProgramError> {
-        match bpf_prog_get_info_by_fd(self.prog_fd) {
+        match bpf_prog_get_info_by_fd(self.prog_fd, &[]) {
             Ok(info) => Ok(ProgramInfo(info)),
             Err(io_error) => Err(ProgramError::SyscallError {
                 call: "bpf_prog_get_info_by_fd",

aya/src/programs/mod.rs

@@ -494,7 +494,8 @@ impl<T: Link> ProgramData<T> {
                 io_error,
             })? as RawFd;
 
-        let info = bpf_prog_get_info_by_fd(fd).map_err(|io_error| ProgramError::SyscallError {
+        let info =
+            bpf_prog_get_info_by_fd(fd, &[]).map_err(|io_error| ProgramError::SyscallError {
                 call: "bpf_prog_get_info_by_fd",
                 io_error,
             })?;
@@ -967,7 +968,8 @@ impl ProgramInfo {
                 io_error,
             })? as RawFd;
 
-        let info = bpf_prog_get_info_by_fd(fd).map_err(|io_error| ProgramError::SyscallError {
+        let info =
+            bpf_prog_get_info_by_fd(fd, &[]).map_err(|io_error| ProgramError::SyscallError {
                 call: "bpf_prog_get_info_by_fd",
                 io_error,
             })?;
@@ -1003,7 +1005,7 @@ impl Iterator for ProgramsIter {
                             io_error,
                         })
                         .and_then(|fd| {
-                            bpf_prog_get_info_by_fd(fd.as_raw_fd())
+                            bpf_prog_get_info_by_fd(fd.as_raw_fd(), &[])
                                 .map_err(|io_error| ProgramError::SyscallError {
                                     call: "bpf_prog_get_info_by_fd",
                                     io_error,

aya/src/sys/bpf.rs

@@ -481,17 +481,21 @@ pub(crate) fn bpf_prog_get_fd_by_id(prog_id: u32) -> Result<OwnedFd, io::Error>
     }
 }
 
-pub(crate) fn bpf_prog_get_info_by_fd(prog_fd: RawFd) -> Result<bpf_prog_info, io::Error> {
+pub(crate) fn bpf_prog_get_info_by_fd(
+    prog_fd: RawFd,
+    map_ids: &[u32],
+) -> Result<bpf_prog_info, io::Error> {
     let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
-    // info gets entirely populated by the kernel
+    let mut info = unsafe { mem::zeroed::<bpf_prog_info>() };
-    let info = MaybeUninit::zeroed();
+    info.map_ids = map_ids.as_ptr() as u64;
+    info.nr_map_ids = map_ids.len() as u32;
 
     attr.info.bpf_fd = prog_fd as u32;
     attr.info.info = &info as *const _ as u64;
     attr.info.info_len = mem::size_of::<bpf_prog_info>() as u32;
 
     match sys_bpf(bpf_cmd::BPF_OBJ_GET_INFO_BY_FD, &attr) {
-        Ok(_) => Ok(unsafe { info.assume_init() }),
+        Ok(_) => Ok(info),
         Err((_, err)) => Err(err),
     }
 }