DataDog · andrewlock · Sep 18, 2024
@@ -464,6 +464,7 @@
               "SignDlls",
               "SignMsi",
               "SummaryOfSnapshotChanges",
+              "TestNativeWrapper",
               "UpdateChangeLog",
               "UpdateSnapshots",
               "UpdateSnapshotsFromBuild",
@@ -680,6 +681,7 @@
               "SignDlls",
               "SignMsi",
               "SummaryOfSnapshotChanges",
+              "TestNativeWrapper",
               "UpdateChangeLog",
               "UpdateSnapshots",
               "UpdateSnapshotsFromBuild",

@@ -201,8 +201,8 @@ void initLibrary(void)
 
     // Bash provides its own version of the getenv/setenv functions
     // Fetch the original ones and use those instead
-    char *(*real_getenv)(const char *) = (char *(*)(const char *))dlsym(RTLD_NEXT, "getenv");
-    int (*real_setenv)(const char *, const char *, int) = (int (*)(const char *, const char *, int))dlsym(RTLD_NEXT, "setenv");
+    char *(*real_getenv)(const char *) = __dd_dlsym(RTLD_NEXT, "getenv");
+    int (*real_setenv)(const char *, const char *, int) = __dd_dlsym(RTLD_NEXT, "setenv");
 
     if (real_getenv == NULL || real_setenv == NULL)
     {

@@ -17,6 +17,7 @@
 using Nuke.Common.Utilities;
 using System.Collections;
 using System.Threading.Tasks;
+using DiffMatchPatch;
 using Logger = Serilog.Log;
 
 partial class Build
@@ -115,6 +116,84 @@ partial class Build
             }
         });
 
+    Target TestNativeWrapper => _ => _
+        .Unlisted()
+        .Description("Test that the Native wrapper symbols haven't changed")
+        .After(CompileProfilerNativeSrc)
+        .OnlyWhenStatic(() => IsLinux)
+        .Executes(() =>
+        {
+            var (arch, _) = GetUnixArchitectureAndExtension();
+            var libraryPath = ProfilerDeployDirectory / arch / LinuxApiWrapperLibrary;
+
+            var output = Nm.Value($"-D {libraryPath}").Select(x => x.Text).ToList();
+
+            // Gives output similar to this:
+            // 0000000000006bc8 D DdDotnetFolder
+            // 0000000000006bd0 D DdDotnetMuslFolder
+            //                  w _ITM_deregisterTMCloneTable
+            //                  w _ITM_registerTMCloneTable
+            //                  w __cxa_finalize
+            //                  w __deregister_frame_info
+            //                  U __errno_location
+            //                  U __tls_get_addr
+            // 0000000000002d1b T _fini
+            // 0000000000002d18 T _init
+            // 0000000000003d70 T accept
+            // 0000000000003e30 T accept4
+            //                  U access
+            //
+            // The types of symbols are:
+            // D: Data section symbol. These symbols are initialized global variables.
+            // w: Weak symbol. These symbols are weakly referenced and can be overridden by other symbols.
+            // U: Undefined symbol. These symbols are referenced in the file but defined elsewhere.
+            // T: Text section symbol. These symbols are functions or executable code.
+            // B: BSS (Block Started by Symbol) section symbol. These symbols are uninitialized global variables.
+            //
+            // We only care about the Undefined symbols - we don't want to accidentally add more of them
+
+            Logger.Debug("NM output: {Output}", string.Join(Environment.NewLine, output));
+
+            var symbols = output
+                .Select(x => x.Trim())
+                .Where(x => x.StartsWith("U "))
+                .Select(x => x.TrimStart("U "))
+                .OrderBy(x => x)
+                .ToList();
+
+
+            var received = string.Join(Environment.NewLine, symbols);
+            var verifiedPath = TestsDirectory / "snapshots" / $"native-wrapper-symbols-{UnixArchitectureIdentifier}.verified.txt";
+            var verified = File.Exists(verifiedPath)
+                ? File.ReadAllText(verifiedPath)
+                : string.Empty;
+
+            Logger.Information("Comparing snapshot of Undefined symbols in the Native Wrapper library using {Path}...", verifiedPath);
+
+            var dmp = new diff_match_patch();
+            var diff = dmp.diff_main(verified, received);
+            dmp.diff_cleanupSemantic(diff);
+
+            var changedSymbols = diff
+                .Where(x => x.operation != Operation.EQUAL)
+                .Select(x => x.text.Trim())
+                .ToList();
+
+            if (changedSymbols.Count == 0)
+            {
+                Logger.Information("No changes found in Undefined symbols in the Native Wrapper library");
+                return;
+            }
+
+            PrintDiff(diff);
+
+            throw new Exception($"Found differences in undefined symbols ({string.Join(",", changedSymbols)}) in the Native Wrapper library. " +
+                                "Verify that these changes are expected, and will not cause problems. " +
+                                "Removing symbols is generally a safe operation, but adding them could cause crashes. " +
+                                $"If the new symbols are safe to add, update the snapshot file at {verifiedPath} with the " +
+                                "new values");
+        });
+
     Target RunProfilerNativeUnitTestsLinux => _ => _
         .Unlisted()
         .Description("Run profiler native unit tests")

@@ -97,6 +97,7 @@ partial class Build
     [LazyPathExecutable(name: "ln")] readonly Lazy<Tool> HardLinkUtil;
     [LazyPathExecutable(name: "cppcheck")] readonly Lazy<Tool> CppCheck;
     [LazyPathExecutable(name: "run-clang-tidy")] readonly Lazy<Tool> RunClangTidy;
+    [LazyPathExecutable(name: "nm")] readonly Lazy<Tool> Nm;
 
     //OSX Tools
     readonly string[] OsxArchs = { "arm64", "x86_64" };

@@ -338,39 +338,7 @@ partial class Build
               var diff = dmp.diff_main(File.ReadAllText(source.ToString().Replace("received", "verified")), File.ReadAllText(source));
               dmp.diff_cleanupSemantic(diff);
 
-              foreach (var t in diff)
-              {
-                  if (t.operation != Operation.EQUAL)
-                  {
-                      var str = DiffToString(t);
-                      if (str.Contains(value: '\n'))
-                      {
-                          // if the diff is multiline, start with a newline so that all changes are aligned
-                          // otherwise it's easy to miss the first line of the diff
-                          str = "\n" + str;
-                      }
-
-                      Logger.Information(str);
-                  }
-              }
-          }
-
-          string DiffToString(Diff diff)
-          {
-              if (diff.operation == Operation.EQUAL)
-              {
-                  return string.Empty;
-              }
-
-              var symbol = diff.operation switch
-              {
-                  Operation.DELETE => '-',
-                  Operation.INSERT => '+',
-                  _ => throw new Exception("Unknown value of the Option enum.")
-              };
-              // put the symbol at the beginning of each line to make diff clearer when whole blocks of text are missing
-              var lines = diff.text.TrimEnd(trimChar: '\n').Split(Environment.NewLine);
-              return string.Join(Environment.NewLine, lines.Select(l => symbol + l));
+              PrintDiff(diff);
           }
       });
 
@@ -527,4 +495,42 @@ private static string GetDefaultRuntimeIdentifier(bool isAlpine)
 
     private static MSBuildTargetPlatform ARM64TargetPlatform = (MSBuildTargetPlatform)"ARM64";
     private static MSBuildTargetPlatform ARM64ECTargetPlatform = (MSBuildTargetPlatform)"ARM64EC";
+
+    private static void PrintDiff(List<Diff> diff, bool printEqual = false)
+    {
+        foreach (var t in diff)
+        {
+            if (printEqual || t.operation != Operation.EQUAL)
+            {
+                var str = DiffToString(t);
+                if (str.Contains(value: '\n'))
+                {
+                    // if the diff is multiline, start with a newline so that all changes are aligned
+                    // otherwise it's easy to miss the first line of the diff
+                    str = "\n" + str;
+                }
+
+                Logger.Information(str);
+            }
+        }
+
+        string DiffToString(Diff diff)
+        {
+            if (diff.operation == Operation.EQUAL)
+            {
+                return string.Empty;
+            }
+
+            var symbol = diff.operation switch
+            {
+                Operation.DELETE => '-',
+                Operation.INSERT => '+',
+                _ => throw new Exception("Unknown value of the Option enum.")
+            };
+            // put the symbol at the beginning of each line to make diff clearer when whole blocks of text are missing
+            var lines = diff.text.TrimEnd(trimChar: '\n').Split(Environment.NewLine);
+            return string.Join(Environment.NewLine, lines.Select(l => symbol + l));
+        }
+
+    }
 }
@@ -211,6 +211,7 @@ void DeleteReparsePoints(string path)
         .Description("Builds the Profiler native and managed src, and publishes the profiler home directory")
         .After(Clean)
         .DependsOn(CompileProfilerNativeSrc)
+        .DependsOn(TestNativeWrapper)
         .DependsOn(PublishProfiler);
 
     Target BuildNativeLoader => _ => _

@@ -0,0 +1,14 @@
+__errno_location
+access
+asprintf
+free
+getauxval
+getenv
+malloc
+strcasecmp
+strcmp
+strcpy
+strlen
+strncmp
+strncpy
+strrchr
@@ -0,0 +1,14 @@
+__errno_location
+__tls_get_addr
+access
+asprintf
+free
+getenv
+malloc
+strcasecmp
+strcmp
+strcpy
+strlen
+strncmp
+strncpy
+strrchr