Missing argument in p/invoke to retrieve username.

dotnet · May 27, 2022 · 1dd8c07 · 1dd8c07
1 parent 2d3bff8
commit 1dd8c07
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Showing 4 changed files with 11 additions and 10 deletions.
diff --git a/src/libraries/Common/src/Interop/Unix/System.Native/Interop.GetPwUid.cs b/src/libraries/Common/src/Interop/Unix/System.Native/Interop.GetPwUid.cs
@@ -25,16 +25,17 @@ internal unsafe struct Passwd
         }
 
         /// <summary>
-        /// Gets the user name associated to the current user's UID.
+        /// Gets the user name associated to the specified UID.
         /// </summary>
-        /// <returns>On success, return a string with the user name. On failure, returns an empty string.</returns>
-        internal static unsafe string GetUserNameFromPasswd()
+        /// <param name="uid">The user ID.</param>
+        /// <returns>On success, return a string with the user name associated to the specified UID. On failure, returns an empty string.</returns>
+        internal static unsafe string GetUserNameFromPasswd(uint uid)
         {
             // First try with a buffer that should suffice for 99% of cases.
             string? username;
             const int BufLen = Interop.Sys.Passwd.InitialBufferSize;
             byte* stackBuf = stackalloc byte[BufLen];
-            if (TryGetUserNameFromPasswd(stackBuf, BufLen, out username))
+            if (TryGetUserNameFromPasswd(uid, stackBuf, BufLen, out username))
             {
                 return username ?? string.Empty;
             }
@@ -48,19 +49,19 @@ internal static unsafe string GetUserNameFromPasswd()
                 byte[] heapBuf = new byte[lastBufLen];
                 fixed (byte* buf = &heapBuf[0])
                 {
-                    if (TryGetUserNameFromPasswd(buf, heapBuf.Length, out username))
+                    if (TryGetUserNameFromPasswd(uid, buf, heapBuf.Length, out username))
                     {
                         return username ?? string.Empty;
                     }
                 }
             }
         }
 
-        private static unsafe bool TryGetUserNameFromPasswd(byte* buf, int bufLen, out string? username)
+        private static unsafe bool TryGetUserNameFromPasswd(uint uid, byte* buf, int bufLen, out string? username)
         {
             // Call getpwuid_r to get the passwd struct
             Interop.Sys.Passwd passwd;
-            int error = Interop.Sys.GetPwUidR(Interop.Sys.GetEUid(), out passwd, buf, bufLen);
+            int error = Interop.Sys.GetPwUidR(uid, out passwd, buf, bufLen);
 
             // If the call succeeds, give back the user name retrieved
             if (error == 0)

diff --git a/src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarWriter.Unix.cs b/src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarWriter.Unix.cs
@@ -68,7 +68,7 @@ partial void ReadFileFromDiskAndWriteToArchiveStreamAsEntry(string fullPath, str
             entry._header._uid = (int)status.Uid;
             if (!_userIdentifiers.TryGetValue(status.Uid, out string? uName))
             {
-                uName = Interop.Sys.GetUserNameFromPasswd();
+                uName = Interop.Sys.GetUserNameFromPasswd(status.Uid);
                 _userIdentifiers.Add(status.Uid, uName);
             }
             entry._header._uName = uName;

diff --git a/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntry.File.Tests.Unix.cs b/src/libraries/System.Formats.Tar/tests/TarWriter/TarWriter.WriteEntry.File.Tests.Unix.cs
@@ -158,7 +158,7 @@ partial void VerifyPlatformSpecificMetadata(string filePath, TarEntry entry)
             if (entry is PosixTarEntry posix)
             {
                 string gname = Interop.Sys.GetGroupName(status.Gid);
-                string uname = Interop.Sys.GetUserNameFromPasswd();
+                string uname = Interop.Sys.GetUserNameFromPasswd(status.Uid);
 
                 Assert.Equal(gname, posix.GroupName);
                 Assert.Equal(uname, posix.UserName);

diff --git a/src/libraries/System.Private.CoreLib/src/System/Environment.Unix.cs b/src/libraries/System.Private.CoreLib/src/System/Environment.Unix.cs
@@ -24,7 +24,7 @@ public static string MachineName
             }
         }
 
-        public static string UserName => Interop.Sys.GetUserNameFromPasswd();
+        public static string UserName => Interop.Sys.GetUserNameFromPasswd(Interop.Sys.GetEUid());
 
         [MethodImplAttribute(MethodImplOptions.NoInlining)] // Avoid inlining PInvoke frame into the hot path
         private static int GetProcessId() => Interop.Sys.GetPid();