Aggregate adjacent memory sizes regardless of r+x

src/libraries/Common/src/Interop/Linux/procfs/Interop.ProcFsStat.ParseMapModules.cs

@@ -0,0 +1,145 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
+using System.IO;
+using System.Text;
+
+internal static partial class Interop
+{
+    internal static partial class procfs
+    {
+        private const string MapsFileName = "/maps";
+
+        private static string GetMapsFilePathForProcess(int pid)
+        {
+            return RootPath + pid.ToString(CultureInfo.InvariantCulture) + MapsFileName;
+        }
+
+        private static (long Start, int Size) TryParseAddressRange(string s, ref int start, ref int end)
+        {
+            int pos = s.IndexOf('-', start, end - start);
+            if (pos > 0)
+            {
+                if (long.TryParse(s.AsSpan(start, pos), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out long startingAddress) &&
+                    long.TryParse(s.AsSpan(pos + 1, end - (pos + 1)), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out long endingAddress))
+                {
+                    return (startingAddress, (int)(endingAddress - startingAddress));
+                }
+            }
+
+            return default;
+        }
+
+        private static bool HasReadAndExecFlags(string s, ref int start, ref int end)
+        {
+            bool sawRead = false, sawExec = false;
+            for (int i = start; i < end; i++)
+            {
+                if (s[i] == 'r')
+                    sawRead = true;
+                else if (s[i] == 'x')
+                    sawExec = true;
+            }
+
+            return sawRead & sawExec;
+        }
+
+        internal static ProcessModuleCollection? ParseMapsModules(int pid)
+        {
+            try
+            {
+                return ParseMapsModulesCore(File.ReadLines(GetMapsFilePathForProcess(pid)));
+            }
+            catch (IOException) { }
+            catch (UnauthorizedAccessException) { }
+
+            return null;
+        }
+
+        private static ProcessModuleCollection ParseMapsModulesCore(IEnumerable<string> lines)
+        {
+            Debug.Assert(lines != null);
+
+            ProcessModule? module = null;
+            ProcessModuleCollection modules = new(capacity: 0);
+            bool moduleHasReadAndExecFlags = false;
+
+            foreach (string line in lines)
+            {
+                // Use a StringParser to avoid string.Split costs
+                var parser = new StringParser(line, separator: ' ', skipEmpty: true);
+
+                // Parse the address start and size
+                (long Start, int Size) addressRange = parser.ParseRaw(TryParseAddressRange);
+
+                if (addressRange == default)
+                {
+                    Commit();
+                    continue;
+                }
+
+                // Parse the permissions
+                bool lineHasReadAndExecFlags = parser.ParseRaw(HasReadAndExecFlags);
+
+                // Skip past the offset, dev, and inode fields
+                parser.MoveNext();
+                parser.MoveNext();
+                parser.MoveNext();
+
+                // Parse the pathname
+                if (!parser.MoveNext())
+                {
+                    Commit();
+                    continue;
+                }
+
+                string pathname = parser.ExtractCurrentToEnd();
+                bool isContinuation = module?.FileName == pathname && (long)module.BaseAddress + module.ModuleMemorySize == addressRange.Start;
+
+                if (isContinuation)
+                {
+                    module!.ModuleMemorySize += addressRange.Size;
+                    continue;
+                }
+
+                Commit();
+                moduleHasReadAndExecFlags |= lineHasReadAndExecFlags;
+
+                module = new ProcessModule
+                {
+                    FileName = pathname,
+                    ModuleName = Path.GetFileName(pathname),
+                    ModuleMemorySize = addressRange.Size,
+                    EntryPointAddress = IntPtr.Zero // unknown
+                };
+
+                // on 32-bit platforms, it throws System.OverflowException without the void* cast.
+                unsafe
+                {
+                    module.BaseAddress = new IntPtr(unchecked((void*)addressRange.Start));
+                }
+            }
+
+            // Commit last line.
+            Commit();
+
+            return modules;
+
+            void Commit()
+            {
+                // we only add module to collection, if at least one row had 'r' and 'x' set.
+                if (moduleHasReadAndExecFlags && module is not null)
+                {
+                    modules.Add(module);
+                    module = null;
+                    moduleHasReadAndExecFlags = false;
+                }
+            }
+        }
+    }
+}

src/libraries/Common/src/Interop/Linux/procfs/Interop.ProcFsStat.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable enable
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -17,7 +16,6 @@ internal static partial class procfs
         private const string ExeFileName = "/exe";
         private const string CmdLineFileName = "/cmdline";
         private const string StatFileName = "/stat";
-        private const string MapsFileName = "/maps";
         private const string FileDescriptorDirectoryName = "/fd/";
         private const string TaskDirectoryName = "/task/";
 
@@ -78,12 +76,6 @@ internal struct ParsedStat
             //internal long cguest_time;
         }
 
-        internal struct ParsedMapsModule
-        {
-            internal string FileName;
-            internal KeyValuePair<long, long> AddressRange;
-        }
-
         internal static string GetExeFilePathForProcess(int pid)
         {
             return RootPath + pid.ToString(CultureInfo.InvariantCulture) + ExeFileName;
@@ -99,11 +91,6 @@ internal static string GetStatFilePathForProcess(int pid)
             return RootPath + pid.ToString(CultureInfo.InvariantCulture) + StatFileName;
         }
 
-        internal static string GetMapsFilePathForProcess(int pid)
-        {
-            return RootPath + pid.ToString(CultureInfo.InvariantCulture) + MapsFileName;
-        }
-
         internal static string GetTaskDirectoryPathForProcess(int pid)
         {
             return RootPath + pid.ToString(CultureInfo.InvariantCulture) + TaskDirectoryName;
@@ -114,80 +101,6 @@ internal static string GetFileDescriptorDirectoryPathForProcess(int pid)
             return RootPath + pid.ToString(CultureInfo.InvariantCulture) + FileDescriptorDirectoryName;
         }
 
-        internal static IEnumerable<ParsedMapsModule> ParseMapsModules(int pid)
-        {
-            try
-            {
-                return ParseMapsModulesCore(File.ReadLines(GetMapsFilePathForProcess(pid)));
-            }
-            catch (IOException) { }
-            catch (UnauthorizedAccessException) { }
-
-            return Array.Empty<ParsedMapsModule>();
-        }
-
-        private static IEnumerable<ParsedMapsModule> ParseMapsModulesCore(IEnumerable<string> lines)
-        {
-            Debug.Assert(lines != null);
-
-            // Parse each line from the maps file into a ParsedMapsModule result
-            foreach (string line in lines)
-            {
-                // Use a StringParser to avoid string.Split costs
-                var parser = new StringParser(line, separator: ' ', skipEmpty: true);
-
-                // Parse the address range
-                KeyValuePair<long, long> addressRange =
-                    parser.ParseRaw(delegate (string s, ref int start, ref int end)
-                    {
-                        long startingAddress = 0, endingAddress = 0;
-                        int pos = s.IndexOf('-', start, end - start);
-                        if (pos > 0)
-                        {
-                            if (long.TryParse(s.AsSpan(start, pos), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out startingAddress))
-                            {
-                                long.TryParse(s.AsSpan(pos + 1, end - (pos + 1)), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out endingAddress);
-                            }
-                        }
-                        return new KeyValuePair<long, long>(startingAddress, endingAddress);
-                    });
-
-                // Parse the permissions (we only care about entries with 'r' and 'x' set)
-                if (!parser.ParseRaw(delegate (string s, ref int start, ref int end)
-                {
-                    bool sawRead = false, sawExec = false;
-                    for (int i = start; i < end; i++)
-                    {
-                        if (s[i] == 'r')
-                            sawRead = true;
-                        else if (s[i] == 'x')
-                            sawExec = true;
-                    }
-                    return sawRead & sawExec;
-                }))
-                {
-                    continue;
-                }
-
-                // Skip past the offset, dev, and inode fields
-                parser.MoveNext();
-                parser.MoveNext();
-                parser.MoveNext();
-
-                // Parse the pathname
-                if (!parser.MoveNext())
-                {
-                    continue;
-                }
-                string pathname = parser.ExtractCurrentToEnd();
-
-                // We only get here if a we have a non-empty pathname and
-                // the permissions included both readability and executability.
-                // Yield the result.
-                yield return new ParsedMapsModule { FileName = pathname, AddressRange = addressRange };
-            }
-        }
-
         private static string GetStatFilePathForThread(int pid, int tid)
         {
             // Perf note: Calling GetTaskDirectoryPathForProcess will allocate a string,

src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj

@@ -279,6 +279,8 @@
              Link="Common\Interop\Linux\Interop.cgroups.cs" />
     <Compile Include="$(CommonPath)Interop\Linux\procfs\Interop.ProcFsStat.cs"
              Link="Common\Interop\Linux\Interop.ProcFsStat.cs" />
+    <Compile Include="$(CommonPath)Interop\Linux\procfs\Interop.ProcFsStat.ParseMapModules.cs"
+             Link="Common\Interop\Linux\Interop.ProcFsStat.ParseMapModules.cs" />
     <Compile Include="$(CommonPath)Interop\Linux\procfs\Interop.ProcFsStat.TryReadStatusFile.cs"
              Link="Common\Interop\Linux\Interop.ProcFsStat.TryReadStatusFile.cs" />
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.SchedGetSetAffinity.cs"

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.Linux.cs

@@ -38,40 +38,7 @@ public static ProcessInfo[] GetProcessInfos(string machineName)
         /// <returns>The array of modules.</returns>
         internal static ProcessModuleCollection GetModules(int processId)
         {
-            var modules = new ProcessModuleCollection(0);
-
-            // Process from the parsed maps file each entry representing a module
-            foreach (Interop.procfs.ParsedMapsModule entry in Interop.procfs.ParseMapsModules(processId))
-            {
-                int sizeOfImage = (int)(entry.AddressRange.Value - entry.AddressRange.Key);
-
-                // A single module may be split across multiple map entries; consolidate based on
-                // the name and address ranges of sequential entries.
-                if (modules.Count > 0)
-                {
-                    ProcessModule module = modules[modules.Count - 1];
-                    if (module.FileName == entry.FileName &&
-                        ((long)module.BaseAddress + module.ModuleMemorySize == entry.AddressRange.Key))
-                    {
-                        // Merge this entry with the previous one
-                        module.ModuleMemorySize += sizeOfImage;
-                        continue;
-                    }
-                }
-
-                // It's not a continuation of a previous entry but a new one: add it.
-                unsafe
-                {
-                    modules.Add(new ProcessModule()
-                    {
-                        FileName = entry.FileName,
-                        ModuleName = Path.GetFileName(entry.FileName),
-                        BaseAddress = new IntPtr(unchecked((void*)entry.AddressRange.Key)),
-                        ModuleMemorySize = sizeOfImage,
-                        EntryPointAddress = IntPtr.Zero // unknown
-                    });
-                }
-            }
+            ProcessModuleCollection modules = Interop.procfs.ParseMapsModules(processId) ?? new(capacity: 0);
 
             // Move the main executable module to be the first in the list if it's not already
             string? exePath = Process.GetExePath(processId);