aya/obj: fix incorrect section size for .bss

aya/src/obj/mod.rs

@@ -410,6 +410,7 @@ struct Section<'a> {
     address: u64,
     name: &'a str,
     data: &'a [u8],
+    size: u64,
     relocations: Vec<Relocation>,
 }
 
@@ -428,6 +429,7 @@ impl<'data, 'file, 'a> TryFrom<&'a ObjSection<'data, 'file>> for Section<'a> {
             address: section.address(),
             name: section.name().map_err(map_err)?,
             data: section.data().map_err(map_err)?,
+            size: section.size(),
             relocations: section
                 .relocations()
                 .map(|(offset, r)| {
@@ -505,7 +507,9 @@ fn parse_map(section: &Section, name: &str) -> Result<Map, ParseError> {
         let def = bpf_map_def {
             map_type: BPF_MAP_TYPE_ARRAY as u32,
             key_size: mem::size_of::<u32>() as u32,
-            value_size: section.data.len() as u32,
+            // We need to use section.size here since
+            // .bss will always have data.len() == 0
+            value_size: section.size as u32,
             max_entries: 1,
             map_flags: 0, /* FIXME: set rodata readonly */
             ..Default::default()
@@ -607,6 +611,7 @@ mod tests {
             address: 0,
             name,
             data,
+            size: data.len() as u64,
             relocations: Vec::new(),
         }
     }