commit d8a4578f30dd1a355591a7b18d139a9ac0a48f72
author Maciej Żenczykowski <maze@google.com> Thu Jan 14 23:36:32 2021 -0800
committer Maciej Żenczykowski <maze@google.com> Wed Jan 20 05:17:14 2021 +0000
tree af3aa7d0539829b97c018231d1f571f62407ebd9
parent da5d7ec6a70f383bcd788b8e6e19aa4fbb25a4df

put tethering bpf maps & programs in /sys/fs/bpf/tethering/...

This makes it harder for system and mainline bpf programs to
conflict with each other, thus enabling easier mainline module
updates.

Test: builds and boots, atest, TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ic1b69bb1ddc4a10bd4861dadbd6b97e2520c532d

libbpf_android/Loader.cpp

diff --git a/libbpf_android/Loader.cpp b/libbpf_android/Loader.cpp
index e61f460..05a5067 100644
--- a/libbpf_android/Loader.cpp
+++ b/libbpf_android/Loader.cpp
@@ -403,7 +403,8 @@
     return getSymName(elfFile, symtab[index].st_name, name);
 }
 
-static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>& mapFds) {
+static int createMaps(const char* elfPath, ifstream& elfFile, vector<unique_fd>& mapFds,
+                      const char* prefix) {
     int ret;
     vector<char> mdData;
     vector<struct bpf_map_def> md;
@@ -421,11 +422,11 @@
 
     for (int i = 0; i < (int)mapNames.size(); i++) {
         unique_fd fd;
-        // Format of pin location is /sys/fs/bpf/map_<filename>_<mapname>
+        // Format of pin location is /sys/fs/bpf/<prefix>map_<filename>_<mapname>
         string mapPinLoc;
         bool reuse = false;
 
-        mapPinLoc = string(BPF_FS_PATH) + "map_" + fname + "_" + string(mapNames[i]);
+        mapPinLoc = string(BPF_FS_PATH) + prefix + "map_" + fname + "_" + string(mapNames[i]);
         if (access(mapPinLoc.c_str(), F_OK) == 0) {
             fd.reset(bpf_obj_get(mapPinLoc.c_str()));
             ALOGD("bpf_create_map reusing map %s, ret: %d\n", mapNames[i].c_str(), fd.get());
@@ -527,7 +528,8 @@
     }
 }
 
-static int loadCodeSections(const char* elfPath, vector<codeSection>& cs, const string& license) {
+static int loadCodeSections(const char* elfPath, vector<codeSection>& cs, const string& license,
+                            const char* prefix) {
     unsigned kvers = kernelVersion();
     int ret, fd;
 
@@ -554,8 +556,10 @@
 
         bool reuse = false;
         // Format of pin location is
-        // /sys/fs/bpf/prog_<filename>_<mapname>
-        string progPinLoc = BPF_FS_PATH "prog_";
+        // /sys/fs/bpf/<prefix>prog_<filename>_<mapname>
+        string progPinLoc = BPF_FS_PATH;
+        progPinLoc += prefix;
+        progPinLoc += "prog_";
         progPinLoc += fname;
         progPinLoc += '_';
         progPinLoc += name;
@@ -609,7 +613,7 @@
     return 0;
 }
 
-int loadProg(const char* elfPath, bool* isCritical) {
+int loadProg(const char* elfPath, bool* isCritical, const char* prefix) {
     vector<char> license;
     vector<char> critical;
     vector<codeSection> cs;
@@ -644,7 +648,7 @@
     /* Just for future debugging */
     if (0) dumpAllCs(cs);
 
-    ret = createMaps(elfPath, elfFile, mapFds);
+    ret = createMaps(elfPath, elfFile, mapFds, prefix);
     if (ret) {
         ALOGE("Failed to create maps: (ret=%d) in %s\n", ret, elfPath);
         return ret;
@@ -655,7 +659,7 @@
 
     applyMapRelo(elfFile, mapFds, cs);
 
-    ret = loadCodeSections(elfPath, cs, string(license.data()));
+    ret = loadCodeSections(elfPath, cs, string(license.data()), prefix);
     if (ret) ALOGE("Failed to load programs, loadCodeSections ret=%d\n", ret);
 
     return ret;