bpf: Maps live in maps section

This forces all maps to the maps section so we remain compatible with
libbpf. This requires #181 to avoid breaking userspace.

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>

bpf/aya-bpf-macros/src/expand.rs

@@ -49,11 +49,13 @@ impl Map {
     }
 
     pub fn expand(&self) -> Result<TokenStream> {
-        let section_name = format!("maps/{}", self.name);
+        let section_name = "maps".to_string();
+        let name = &self.name;
         let item = &self.item;
         Ok(quote! {
             #[no_mangle]
             #[link_section = #section_name]
+            #[export_name = #name]
             #item
         })
     }

test/cases/020_elf/000_maps/map_test.ebpf.rs

@@ -0,0 +1,37 @@
+//! ```cargo
+//! [dependencies]
+//! aya-bpf = { path = "../../../../bpf/aya-bpf" }
+//! ```
+
+#![no_std]
+#![no_main]
+
+use aya_bpf::{
+    bindings::xdp_action,
+    macros::{map, xdp},
+    programs::XdpContext,
+    maps::Array,
+};
+
+#[map]
+static mut FOO: Array<u32> = Array::<u32>::with_max_entries(10, 0);
+
+#[map(name = "BAR")]
+static mut BAZ: Array<u32> = Array::<u32>::with_max_entries(10, 0);
+
+#[xdp]
+pub fn pass(ctx: XdpContext) -> u32 {
+    match unsafe { try_pass(ctx) } {
+        Ok(ret) => ret,
+        Err(_) => xdp_action::XDP_ABORTED,
+    }
+}
+
+unsafe fn try_pass(_ctx: XdpContext) -> Result<u32, u32> {
+    Ok(xdp_action::XDP_PASS)
+}
+
+#[panic_handler]
+fn panic(_info: &core::panic::PanicInfo) -> ! {
+    unsafe { core::hint::unreachable_unchecked() }
+}

test/cases/020_elf/000_maps/test.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+# SUMMARY: Check that maps are correctly represented in ELF files
+# LABELS:
+
+set -ex
+
+# Source libraries. Uncomment if needed/defined
+#. "${RT_LIB}"
+. "${RT_PROJECT_ROOT}/_lib/lib.sh"
+
+NAME=map_test
+
+clean_up() {
+    rm -rf ebpf user ${NAME}.o
+}
+
+trap clean_up EXIT
+
+# Test code goes here
+compile_ebpf ${NAME}.ebpf.rs
+
+readelf --sections ${NAME}.o | grep -q "maps"
+readelf --syms ${NAME}.o | grep -q "BAR"
+
+exit 0

test/cases/020_elf/group.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+# SUMMARY: Tests to check ELF from aya-bpf
+# LABELS:
+
+# Source libraries. Uncomment if needed/defined
+# . "${RT_LIB}"
+. "${RT_PROJECT_ROOT}/_lib/lib.sh"
+
+set -e
+
+group_init() {
+    # Group initialisation code goes here
+    return 0
+}
+
+group_deinit() {
+    # Group de-initialisation code goes here
+    return 0
+}
+
+CMD=$1
+case $CMD in
+init)
+    group_init
+    res=$?
+    ;;
+deinit)
+    group_deinit
+    res=$?
+    ;;
+*)
+    res=1
+    ;;
+esac
+
+exit $res