BpfMap.getOrCreate(size, path, type) -> BpfMap.init(path)

We don't have the appropriate selinux privs to create the maps anyway.

Test: builds (when combined with system/netd change)
      'git grep getOrCreate' in system/{bpf,netd} comes up empty
      atest netd_unit_test netd_integration_test libbpf_android_test
Bug: 65674744
Bug: 129654883
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Idffbce5b28b723943c6495cfafdecddc7a0f4e67

2 files changed, 8 insertions, 28 deletions

diff --git a/libbpf_android/BpfMapTest.cpp b/libbpf_android/BpfMapTest.cpp
index 74fc2b8..cfa9d88 100644
--- a/libbpf_android/BpfMapTest.cpp
+++ b/libbpf_android/BpfMapTest.cpp
@@ -174,7 +174,7 @@ TEST_F(BpfMapTest, SetUpMap) {
     EXPECT_EQ(0, access(PINNED_MAP_PATH, R_OK));
     checkMapValid(testMap1);
     BpfMap<uint32_t, uint32_t> testMap2;
-    EXPECT_OK(testMap2.getOrCreate(TEST_MAP_SIZE, PINNED_MAP_PATH, BPF_MAP_TYPE_HASH));
+    EXPECT_OK(testMap2.init(PINNED_MAP_PATH));
     checkMapValid(testMap2);
     uint32_t key = TEST_KEY1;
     uint32_t value = TEST_VALUE1;
diff --git a/libbpf_android/include/bpf/BpfMap.h b/libbpf_android/include/bpf/BpfMap.h
index a274b01..d47698e 100644
--- a/libbpf_android/include/bpf/BpfMap.h
+++ b/libbpf_android/include/bpf/BpfMap.h
@@ -100,10 +100,8 @@ class BpfMap {
         return netdutils::status::ok;
     }
 
-    // Function that tries to get map from a pinned path, if the map doesn't
-    // exist yet, create a new one and pinned to the path.
-    netdutils::Status getOrCreate(const uint32_t maxEntries, const char* path,
-                                  const bpf_map_type mapType);
+    // Function that tries to get map from a pinned path.
+    netdutils::Status init(const char* path);
 
     // Iterate through the map and handle each key retrieved based on the filter
     // without modification of map content.
@@ -168,31 +166,13 @@ class BpfMap {
 };
 
 template <class Key, class Value>
-netdutils::Status BpfMap<Key, Value>::getOrCreate(const uint32_t maxEntries, const char* path,
-                                                  bpf_map_type mapType) {
-    int ret = access(path, R_OK);
-    /* Check the pinned location first to check if the map is already there.
-     * otherwise create a new one.
-     */
-    if (ret == 0) {
-        mMapFd = base::unique_fd(mapRetrieve(path, 0));
-        if (mMapFd == -1) {
-            reset();
-            return netdutils::statusFromErrno(
+netdutils::Status BpfMap<Key, Value>::init(const char* path) {
+    mMapFd = base::unique_fd(mapRetrieve(path, 0));
+    if (mMapFd == -1) {
+        reset();
+        return netdutils::statusFromErrno(
                 errno,
                 base::StringPrintf("pinned map not accessible or does not exist: (%s)\n", path));
-        }
-    } else if (ret == -1 && errno == ENOENT) {
-        mMapFd = base::unique_fd(
-            createMap(mapType, sizeof(Key), sizeof(Value), maxEntries, BPF_F_NO_PREALLOC));
-        if (mMapFd == -1) {
-            reset();
-            return netdutils::statusFromErrno(errno,
-                                              base::StringPrintf("map create failed!: %s", path));
-        }
-    } else {
-        return netdutils::statusFromErrno(
-            errno, base::StringPrintf("pinned map not accessible: %s", path));
     }
     return netdutils::status::ok;
 }