From 667dfa97e6be3cb37884ae43e29b118c6ecfa13f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= <maze@google.com>
Date: Wed, 30 Jul 2025 17:26:15 -0700
Subject: [PATCH] bpf: switch map 'pin_subdir' to 'pin_prefix'
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which simplifies NetBpfLoad logic

Test: TreeHugger
Flag: EXEMPT mainline
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I3600cf45ae14a20801b5beca0aa9e79bb3052c57
---
 bpf/loader/NetBpfLoad.cpp       | 11 ++---------
 bpf/progs/include/bpf_helpers.h |  2 +-
 bpf/progs/include/bpf_map_def.h |  8 ++------
 3 files changed, 5 insertions(+), 16 deletions(-)

diff --git a/bpf/loader/NetBpfLoad.cpp b/bpf/loader/NetBpfLoad.cpp
index 4c2df43d8c..d4dc38d62e 100644
--- a/bpf/loader/NetBpfLoad.cpp
+++ b/bpf/loader/NetBpfLoad.cpp
@@ -880,13 +880,6 @@ static enum bpf_map_type sanitizeMapType(enum bpf_map_type type) {
     return type;
 }
 
-static string buildMapPinLoc(const char pin_subdir[BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE],
-                             const string& objName, const string& mapName) {
-    // Format of pin location is /sys/fs/bpf/<pin_subdir>map_<objName>_<mapName>
-    // Note: <objName> refers to the extension-less basename of the .o file (without @ suffix).
-    return string(BPF_FS_PATH) + pin_subdir + "map_" + objName + "_" + mapName;
-}
-
 static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>& mapFds,
                       const unsigned int bpfloader_ver) {
     int ret;
@@ -967,7 +960,7 @@ static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>&
             if (max_entries < page_size) max_entries = page_size;
         }
 
-        string mapPinLoc = buildMapPinLoc(md[i].pin_subdir, objName, mapNames[i]);
+        string mapPinLoc = string(md[i].pin_prefix) + mapNames[i];
         unique_fd fd;
         int saved_errno;
 
@@ -1368,7 +1361,7 @@ static int pinMaps(const char* const elfPath, const struct bpf_object* obj,
         // This map was skipped
         if (!bpf_map__autocreate(m)) continue;
 
-        string mapPinLoc = buildMapPinLoc(md[i].pin_subdir, objName, mapNames[i]);
+        string mapPinLoc = string(md[i].pin_prefix) + mapNames[i];
         if (access(mapPinLoc.c_str(), F_OK) == 0) {
             ALOGE("Reusing map is not supported: %s", mapNames[i].c_str());
             return -1;
diff --git a/bpf/progs/include/bpf_helpers.h b/bpf/progs/include/bpf_helpers.h
index 53daa7470e..abf0994db3 100644
--- a/bpf/progs/include/bpf_helpers.h
+++ b/bpf/progs/include/bpf_helpers.h
@@ -260,7 +260,7 @@ static int (*bpf_sk_storage_delete_unsafe) (const void* sk_storage,
         .min_kver = (minkver).kver,                                         \
         .max_kver = (maxkver).kver,                                         \
         .create_location = CREATE_LOCATION(selinux),                        \
-        .pin_subdir = pindir "/",                                           \
+        .pin_prefix = "/sys/fs/bpf/" pindir "/map_" BPF_OBJ_NAME "_",       \
     };
 
 #define __uint(name, val) int (*name)[val]
diff --git a/bpf/progs/include/bpf_map_def.h b/bpf/progs/include/bpf_map_def.h
index 8b998f9bbc..3034e496da 100644
--- a/bpf/progs/include/bpf_map_def.h
+++ b/bpf/progs/include/bpf_map_def.h
@@ -141,13 +141,9 @@ struct bpf_map_def {
     unsigned int min_kver;
     unsigned int max_kver;
 
-    // These are fixed length strings, padded with null bytes
-    //
-    // overrides default selinux context (which is based on pin subdir)
+    // These are fixed length ASCIIZ strings, padded with null bytes
     char create_location[BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE];
-    //
-    // overrides default prefix (which is based on .o location)
-    char pin_subdir[BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE];
+    char pin_prefix[BPF_PIN_SUBDIR_CHAR_ARRAY_SIZE];
 };
 
 // This needs to be updated whenever the above structure definition is expanded.