OSDescription.Linux: return a user-friendly name based on /etc/os-rel…

…ease.
dotnet · Mar 27, 2023 · 8451453 · 8451453
1 parent 9b38f2a
commit 8451453
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Showing 7 changed files with 176 additions and 2 deletions.
diff --git a/src/libraries/Common/src/Interop/Linux/os-release/Interop.OSReleaseFile.cs b/src/libraries/Common/src/Interop/Linux/os-release/Interop.OSReleaseFile.cs
@@ -0,0 +1,82 @@
+// 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.IO;
+
+internal static partial class Interop
+{
+    // Parse information from '/etc/os-release'.
+    internal static class OSReleaseFile
+    {
+        private const string EtcOsReleasePath = "/etc/os-release";
+
+        /// <summary>
+        /// Returns a user-friendly distribution name.
+        /// </summary>
+        internal static string? GetPrettyName(string filename = EtcOsReleasePath)
+        {
+            if (File.Exists(filename))
+            {
+                string[] lines;
+                try
+                {
+                    lines = File.ReadAllLines(filename);
+                }
+                catch
+                {
+                    return null;
+                }
+
+                // Parse the NAME, PRETTY_NAME, and VERSION fields.
+                // These fields are suitable for presentation to the user.
+                string? prettyName = null, name = null, version = null;
+                foreach (var line in lines)
+                {
+                    if (line.StartsWith("PRETTY_NAME=", StringComparison.Ordinal))
+                    {
+                        prettyName = line.Substring("PRETTY_NAME=".Length);
+                    }
+                    else if (line.StartsWith("NAME=", StringComparison.Ordinal))
+                    {
+                        name = line.Substring("NAME=".Length);
+                    }
+                    else if (line.StartsWith("VERSION=", StringComparison.Ordinal))
+                    {
+                        version = line.Substring("VERSION=".Length);
+                    }
+                }
+
+                // Prefer PRETTY_NAME.
+                if (prettyName is not null)
+                {
+                    return GetValue(prettyName);
+                }
+
+                // Fall back to: NAME[ VERSION].
+                if (name is not null)
+                {
+                    if (version is not null)
+                    {
+                        return $"{GetValue(name)} {GetValue(version)}";
+                    }
+                    return GetValue(name);
+                }
+
+                static string GetValue(string fieldValue)
+                {
+                    // Remove enclosing quotes.
+                    if ((fieldValue.StartsWith('"') && fieldValue.EndsWith('"')) ||
+                        (fieldValue.StartsWith('\'') && fieldValue.EndsWith('\'')))
+                    {
+                        fieldValue = fieldValue.Substring(1, fieldValue.Length - 2);
+                    }
+
+                    return fieldValue;
+                }
+            }
+
+            return null;
+        }
+    }
+}
diff --git a/src/libraries/Common/tests/Common.Tests.csproj b/src/libraries/Common/tests/Common.Tests.csproj
@@ -16,6 +16,8 @@
              Link="Common\Interop\Linux\procfs\Interop.ProcFsStat.cs" />
     <Compile Include="$(CommonPath)Interop\Linux\procfs\Interop.ProcFsStat.TryReadStatusFile.cs"
              Link="Common\Interop\Linux\Interop.ProcFsStat.TryReadStatusFile.cs" />
+    <Compile Include="$(CommonPath)Interop\Linux\os-release\Interop.OSReleaseFile.cs"
+             Link="Common\Interop\Linux\os-release\Interop.OSReleaseFile.cs" />
     <Compile Include="$(CommonPath)System\CharArrayHelpers.cs"
              Link="Common\System\CharArrayHelpers.cs" />
     <Compile Include="$(CommonPath)System\StringExtensions.cs"
@@ -78,6 +80,7 @@
              Link="System\PasteArguments.cs" />
     <Compile Include="Tests\Interop\cgroupsTests.cs" />
     <Compile Include="Tests\Interop\procfsTests.cs" />
+    <Compile Include="Tests\Interop\osReleaseTests.cs" />
     <Compile Include="Tests\System\IO\PathInternal.Tests.cs" />
     <Compile Include="Tests\System\IO\StringParserTests.cs" />
     <Compile Include="Tests\System\Net\HttpDateParserTests.cs" />

diff --git a/src/libraries/Common/tests/Tests/Interop/osReleaseTests.cs b/src/libraries/Common/tests/Tests/Interop/osReleaseTests.cs
@@ -0,0 +1,69 @@
+// 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.IO;
+using System.Text;
+using Xunit;
+
+namespace Common.Tests
+{
+    public class osReleaseTests
+    {
+        [Theory]
+        // Double quotes:
+        [InlineData("NAME=\"Fedora\"\nVERSION=\"37\"\nPRETTY_NAME=\"Fedora Linux 37\"", "Fedora Linux 37")]
+        [InlineData("NAME=\"Fedora\"\nVERSION=\"37\"", "Fedora 37")]
+        [InlineData("NAME=\"Fedora\"", "Fedora")]
+        // Single quotes:
+        [InlineData("NAME='Ubuntu'\nVERSION='22.04'\nPRETTY_NAME='Ubuntu Linux 22.04'", "Ubuntu Linux 22.04")]
+        [InlineData("NAME='Ubuntu'\nVERSION='22.04'", "Ubuntu 22.04")]
+        [InlineData("NAME='Ubuntu'", "Ubuntu")]
+        // No quotes:
+        [InlineData("NAME=Alpine\nVERSION=3.14\nPRETTY_NAME=Alpine_Linux_3.14", "Alpine_Linux_3.14")]
+        [InlineData("NAME=Alpine\nVERSION=3.14", "Alpine 3.14")]
+        [InlineData("NAME=Alpine", "Alpine")]
+        // No pretty name fields:
+        [InlineData("ID=fedora\nVERSION_ID=37", null)]
+        [InlineData("", null)]
+        public static void GetPrettyName_Success(
+            string content,
+            string expectedName)
+        {
+            string path = Path.GetTempFileName();
+            try
+            {
+                File.WriteAllText(path, content);
+
+                string? name = Interop.OSReleaseFile.GetPrettyName(path);
+                Assert.Equal(expectedName, name);
+            }
+            finally { File.Delete(path); }
+        }
+
+        [Fact]
+        public static void GetPrettyName_NoFile_ReturnsNull()
+        {
+            string path = Path.GetRandomFileName();
+            Assert.False(File.Exists(path));
+
+            string? name = Interop.OSReleaseFile.GetPrettyName(path);
+            Assert.Null(name);
+        }
+
+        [Fact, PlatformSpecific(TestPlatforms.Linux)]
+        public static void GetPrettyName_CannotRead_ReturnsNull()
+        {
+            string path = Path.GetTempFileName();
+            try
+            {
+                File.SetUnixFileMode(path, UnixFileMode.None);
+                Assert.ThrowsAny<Exception>(() => File.ReadAllText(path));
+
+                string? name = Interop.OSReleaseFile.GetPrettyName(path);
+                Assert.Null(name);
+            }
+            finally { File.Delete(path); }
+        }
+    }
+}
diff --git a/src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems b/src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems
@@ -2379,6 +2379,7 @@
     <Compile Include="$(CommonPath)System\IO\StringParser.cs" Condition="'$(TargetsLinux)' == 'true'" Link="Common\System\IO\StringParser.cs" />
     <Compile Include="$(CommonPath)Interop\OSX\Interop.libproc.GetProcessInfoById.cs" Condition="'$(TargetsOSX)' == 'true' or '$(TargetsMacCatalyst)' == 'true'" Link="Common\Interop\OSX\Interop.libproc.GetProcessInfoById.cs" />
     <Compile Include="$(CommonPath)Interop\SunOS\procfs\Interop.ProcFsStat.TryReadProcessStatusInfo.cs" Condition="'$(Targetsillumos)' == 'true' or '$(TargetsSolaris)' == 'true'" Link="Common\Interop\SunOS\Interop.ProcFsStat.TryReadProcessStatusInfo.cs" />
+    <Compile Include="$(CommonPath)Interop\Linux\os-release\Interop.OSReleaseFile.cs" Condition="'$(TargetsBrowser)' != 'true' and '$(TargetsWasi)' != 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Environment.Unix.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Environment.FreeBSD.cs" Condition="'$(TargetsFreeBSD)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Environment.Linux.cs" Condition="'$(TargetsLinux)' == 'true'" />

diff --git a/...ries/System.Private.CoreLib/src/System/Runtime/InteropServices/RuntimeInformation.Unix.cs b/...ries/System.Private.CoreLib/src/System/Runtime/InteropServices/RuntimeInformation.Unix.cs
@@ -10,7 +10,7 @@ public static partial class RuntimeInformation
         private static string? s_osDescription;
         private static volatile int s_osArchPlusOne;
 
-        public static string OSDescription => s_osDescription ??= Interop.Sys.GetUnixVersion();
+        public static string OSDescription => s_osDescription ??= (GetPrettyOSDescription() ?? Interop.Sys.GetUnixVersion());
 
         public static Architecture OSArchitecture
         {
@@ -30,5 +30,15 @@ public static Architecture OSArchitecture
                 return (Architecture)osArch;
             }
         }
+
+        private static string? GetPrettyOSDescription()
+        {
+            if (OperatingSystem.IsLinux())
+            {
+                return Interop.OSReleaseFile.GetPrettyName();
+            }
+
+            return null;
+        }
     }
 }
diff --git a/...libraries/System.Runtime.InteropServices.RuntimeInformation/tests/DescriptionNameTests.cs b/...libraries/System.Runtime.InteropServices.RuntimeInformation/tests/DescriptionNameTests.cs
@@ -201,7 +201,14 @@ public void VerifyWindowsName()
         [Fact, PlatformSpecific(TestPlatforms.Linux)]  // Checks Linux name in RuntimeInformation
         public void VerifyLinuxName()
         {
-            Assert.Contains("linux", RuntimeInformation.OSDescription, StringComparison.OrdinalIgnoreCase);
+            if (File.Exists("/etc/os/release"))
+            {
+                Assert.Equal(Interop.OSReleaseFile.GetPrettyName("/etc/os-release"), RuntimeInformation.OSDescription);
+            }
+            else
+            {
+                Assert.Contains("linux", RuntimeInformation.OSDescription, StringComparison.OrdinalIgnoreCase);
+            }
         }
 
         [Fact, PlatformSpecific(TestPlatforms.NetBSD)]  // Checks NetBSD name in RuntimeInformation

diff --git a/...s.RuntimeInformation/tests/System.Runtime.InteropServices.RuntimeInformation.Tests.csproj b/...s.RuntimeInformation/tests/System.Runtime.InteropServices.RuntimeInformation.Tests.csproj
@@ -10,5 +10,7 @@
     <Compile Include="DescriptionNameTests.cs" />
     <Compile Include="$(CommonPath)Interop\Linux\cgroups\Interop.cgroups.cs"
              Link="Common\Interop\Linux\Interop.cgroups.cs" />
+    <Compile Include="$(CommonPath)Interop\Linux\os-release\Interop.OSReleaseFile.cs"
+             Link="Interop\Linux\os-release\Interop.OSReleaseFile.cs" />
   </ItemGroup>
 </Project>