Fix Parent property on processes with complex name (PowerShell#17545)

Author: jborean93

src/System.Management.Automation/CoreCLR/CorePsPlatform.cs

@@ -883,20 +883,40 @@ public static int GetProcFSParentPid(int pid)
             {
                 const int invalidPid = -1;
 
-                // read /proc/<pid>/stat
-                // 4th column will contain the ppid, 92 in the example below
-                // ex: 93 (bash) S 92 93 2 4294967295 ...
-                var path = $"/proc/{pid}/stat";
+                // read /proc/<pid>/status
+                // Row beginning with PPid: \d is the parent process id.
+                // This used to check /proc/<pid>/stat but that file was meant
+                // to be a space delimited line but it contains a value which
+                // could contain spaces itself. Using the status file is a lot
+                // simpler because each line contains a record with a simple
+                // label.
+                // https://github.com/PowerShell/PowerShell/issues/17541#issuecomment-1159911577
+                var path = $"/proc/{pid}/status";
                 try
                 {
-                    var stat = System.IO.File.ReadAllText(path);
-                    var parts = stat.Split(' ', 5);
-                    if (parts.Length < 5)
+                    using FileStream fs = File.OpenRead(path);
+                    using StreamReader sr = new(fs);
+                    string line;
+                    while ((line = sr.ReadLine()) != null)
                     {
-                        return invalidPid;
+                        if (!line.StartsWith("PPid:\t", StringComparison.OrdinalIgnoreCase))
+                        {
+                            continue;
+                        }
+
+                        string[] lineSplit = line.Split('\t', 2, StringSplitOptions.RemoveEmptyEntries);
+                        if (lineSplit.Length != 2)
+                        {
+                            continue;
+                        }
+
+                        if (int.TryParse(lineSplit[1].Trim(), out var ppid))
+                        {
+                            return ppid;
+                        }
                     }
 
-                    return int.Parse(parts[3]);
+                    return invalidPid;
                 }
                 catch (Exception)
                 {

test/powershell/Modules/Microsoft.PowerShell.Management/Get-Process.Tests.ps1

@@ -22,7 +22,7 @@ Describe "Get-Process for admin" -Tags @('CI', 'RequireAdminOnWindows') {
             $pwshVersion.FileBuildPart | Should -BeExactly $PSVersionTable.PSVersion.Patch
             $gitCommitId = $PSVersionTable.GitCommitId
             if ($gitCommitId.StartsWith("v")) { $gitCommitId = $gitCommitId.Substring(1) }
-            $productVersion = $pwshVersion.ProductVersion.Replace(" Commits: ","-").Replace(" SHA: ","-g")
+            $productVersion = $pwshVersion.ProductVersion.Replace(" Commits: ", "-").Replace(" SHA: ", "-g")
             $productVersion | Should -Match $gitCommitId
         } else {
             $pwshVersion.FileVersion | Should -BeNullOrEmpty
@@ -46,7 +46,7 @@ Describe "Get-Process" -Tags "CI" {
         $idleProcessPid = 0
     }
     It "Should return a type of Object[] for Get-Process cmdlet" -Pending:$IsMacOS {
-        ,$ps | Should -BeOfType System.Object[]
+        , $ps | Should -BeOfType System.Object[]
     }
 
     It "Should have not empty Name flags set for Get-Process object" -Pending:$IsMacOS {
@@ -78,7 +78,7 @@ Describe "Get-Process" -Tags "CI" {
         (Get-Process -Id $PID).Id | Should -BeExactly $PID
     }
 
-    It "Should fail to run Get-Process with -IncludeUserName without admin" -Skip:(!$IsWindows)  {
+    It "Should fail to run Get-Process with -IncludeUserName without admin" -Skip:(!$IsWindows) {
         { Get-Process -IncludeUserName } | Should -Throw -ErrorId "IncludeUserNameRequiresElevation,Microsoft.PowerShell.Commands.GetProcessCommand"
     }
 
@@ -95,7 +95,7 @@ Describe "Get-Process" -Tags "CI" {
         { Get-Process -FileVersionInfo -ErrorAction Stop } | Should -Throw -ErrorId "CouldNotEnumerateFileVer,Microsoft.PowerShell.Commands.GetProcessCommand"
     }
 
-    It "Should return CommandLine property" -Skip:($IsMacOS)  {
+    It "Should return CommandLine property" -Skip:($IsMacOS) {
         $command = "(Get-Process -Id `$pid).CommandLine"
         $result = & "$PSHOME/pwsh" -NoProfile -NonInteractive -Command $command
         $result | Should -BeLike "*$command*"
@@ -105,19 +105,18 @@ Describe "Get-Process" -Tags "CI" {
 Describe "Get-Process Formatting" -Tags "Feature" {
     BeforeAll {
         $skip = $false
-        if ($IsWindows)
-        {
+        if ($IsWindows) {
             # on Windows skip this test until issue #11016 is resolved
             $skip = $true
         }
     }
 
     It "Should not have Handle in table format header" -Skip:$skip {
-        $types = "System.Diagnostics.Process","System.Diagnostics.Process#IncludeUserName"
+        $types = "System.Diagnostics.Process", "System.Diagnostics.Process#IncludeUserName"
 
         foreach ($type in $types) {
             $formatData = Get-FormatData -TypeName $type -PowerShellVersion $PSVersionTable.PSVersion
-            $tableControls = $formatData.FormatViewDefinition | Where-Object {$_.Control -is "System.Management.Automation.TableControl"}
+            $tableControls = $formatData.FormatViewDefinition | Where-Object { $_.Control -is "System.Management.Automation.TableControl" }
             foreach ($tableControl in $tableControls) {
                 $tableControl.Control.Headers.Label -match "Handle*" | Should -BeNullOrEmpty
                 # verify that rows without headers isn't the handlecount (as PowerShell will create a header that matches the property name)
@@ -138,5 +137,26 @@ Describe "Process Parent property" -Tags "CI" {
         $powershellexe = (Get-Process -Id $PID).mainmodule.filename
         & $powershellexe -noprofile -command '(Get-Process -Id $PID).Parent.Id' | Should -Be $PID
     }
+
+    It "Can find parent with spaces and parenthesis in the name on non-Windows" -Skip:($IsWindows) {
+        # Bug. See https://github.com/PowerShell/PowerShell/issues/12908
+        $commandName = 't ( e ( s ) t )'
+
+        $script = @'
+#!/bin/sh
+
+while true; do sleep 1; done
+'@
+
+        # Can't use testdrive: as unelevated user doesn't have perms in test in CI
+        Set-Content -Path /tmp/$commandName -Value $script
+        chmod +x (Resolve-Path -Path /tmp/$commandName -Relative)
+        try {
+            $p = Start-Process -FilePath /tmp/$commandName -PassThru
+            $p.Parent.Id | Should -Be $pid
+        } finally {
+            $p | Stop-Process
+        }
+    }
 }