Add Environment.ProcessPath (#42768)

Fixes #40862

Co-authored-by: Stephen Toub <stoub@microsoft.com>
Co-authored-by: Ryan Lucia <ryan@luciaonline.net>

src/libraries/Common/src/Interop/Unix/System.Native/Interop.GetLine.cs → src/libraries/Common/src/Interop/Unix/System.Native/Interop.GetProcessPath.cs

@@ -1,14 +1,16 @@
 // 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.Runtime.InteropServices;
 
 internal static partial class Interop
 {
     internal static partial class Sys
     {
-        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_GetLine", SetLastError = true)]
-        internal static extern string GetLine(IntPtr stream);
+        /// <summary>
+        /// Returns the full path to the executable for the current process, resolving symbolic links.
+        /// </summary>
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_GetProcessPath", SetLastError = true)]
+        internal static extern string? GetProcessPath();
     }
 }

src/libraries/Common/src/Interop/Windows/Kernel32/Interop.GetModuleFileName.cs

@@ -0,0 +1,16 @@
+// 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.Runtime.InteropServices;
+using System.Text;
+using Microsoft.Win32;
+
+internal static partial class Interop
+{
+    internal static unsafe partial class Kernel32
+    {
+        [DllImport(Libraries.Kernel32, EntryPoint = "GetModuleFileNameW", SetLastError = true, CharSet = CharSet.Unicode, ExactSpelling = true)]
+        internal static extern uint GetModuleFileName(IntPtr hModule, ref char lpFilename, uint nSize);
+    }
+}

src/libraries/Native/Unix/CMakeLists.txt

@@ -156,10 +156,6 @@ if (CLR_CMAKE_TARGET_LINUX)
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_GNU_SOURCE")
 endif ()
 
-if(CLR_CMAKE_TARGET_FREEBSD)
-    add_definitions(-D_BSD_SOURCE) # required for getline
-endif(CLR_CMAKE_TARGET_FREEBSD)
-
 # CLR_ADDITIONAL_LINKER_FLAGS - used for passing additional arguments to linker
 # CLR_ADDITIONAL_COMPILER_OPTIONS - used for passing additional arguments to compiler
 #

src/libraries/Native/Unix/System.Native/pal_io.c

@@ -40,11 +40,6 @@
 // Somehow, AIX mangles the definition for this behind a C++ def
 // Redeclare it here
 extern int     getpeereid(int, uid_t *__restrict__, gid_t *__restrict__);
-// This function declaration is hidden behind `_XOPEN_SOURCE=700`, but we need
-// `_ALL_SOURCE` to build the runtime, and that resets that definition to 600.
-// Instead of trying to wrangle ifdefs in system headers with more definitions,
-// just declare it here.
-extern ssize_t  getline(char **, size_t *, FILE *);
 #endif
 
 #if HAVE_STAT64
@@ -961,17 +956,6 @@ int32_t SystemNative_PosixFAdvise(intptr_t fd, int64_t offset, int64_t length, i
 #endif
 }
 
-char* SystemNative_GetLine(FILE* stream)
-{
-    assert(stream != NULL);
-
-    char* lineptr = NULL;
-    size_t n = 0;
-    ssize_t length = getline(&lineptr, &n, stream);
-
-    return length >= 0 ? lineptr : NULL;
-}
-
 int32_t SystemNative_Read(intptr_t fd, void* buffer, int32_t bufferSize)
 {
     return Common_Read(fd, buffer, bufferSize);

src/libraries/Native/Unix/System.Native/pal_io.h

@@ -598,13 +598,6 @@ PALEXPORT int32_t SystemNative_Poll(PollEvent* pollEvents, uint32_t eventCount,
  */
 PALEXPORT int32_t SystemNative_PosixFAdvise(intptr_t fd, int64_t offset, int64_t length, int32_t advice);
 
-/**
-* Reads a line from the provided stream.
-*
-* Returns the read line, or null if no line could be read.  The caller is responsible for freeing the malloc'd line.
-*/
-PALEXPORT char* SystemNative_GetLine(FILE* stream);
-
 /**
  * Reads the number of bytes specified into the provided buffer from the specified, opened file descriptor.
  *

src/libraries/Native/Unix/System.Native/pal_process.c

@@ -28,6 +28,15 @@
 #include <sched.h>
 #endif
 
+#ifdef __APPLE__
+#include <mach-o/dyld.h>
+#endif
+
+#ifdef __FreeBSD__
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#endif
 
 // Validate that our SysLogPriority values are correct for the platform
 c_static_assert(PAL_LOG_EMERG == LOG_EMERG);
@@ -516,19 +525,6 @@ done:;
 #endif
 }
 
-FILE* SystemNative_POpen(const char* command, const char* type)
-{
-    assert(command != NULL);
-    assert(type != NULL);
-    return popen(command, type);
-}
-
-int32_t SystemNative_PClose(FILE* stream)
-{
-    assert(stream != NULL);
-    return pclose(stream);
-}
-
 // Each platform type has it's own RLIMIT values but the same name, so we need
 // to convert our standard types into the platform specific ones.
 static int32_t ConvertRLimitResourcesPalToPlatform(RLimitResources value)
@@ -871,3 +867,57 @@ int32_t SystemNative_SchedGetAffinity(int32_t pid, intptr_t* mask)
     return result;
 }
 #endif
+
+// Returns the full path to the executable for the current process, resolving symbolic links.
+// The caller is responsible for releasing the buffer. Returns null on error.
+char* SystemNative_GetProcessPath()
+{
+#if defined(__APPLE__)
+    uint32_t path_length = 0;
+    if (_NSGetExecutablePath(NULL, &path_length) != -1)
+    {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    char path_buf[path_length];
+    if (_NSGetExecutablePath(path_buf, &path_length) != 0)
+    {
+        errno = EINVAL;
+        return NULL;
+    }
+
+    return realpath(path_buf, NULL);
+#elif defined(__FreeBSD__)
+    static const int name[] =
+    {
+        CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1
+    };
+
+    char path[PATH_MAX];
+    size_t len;
+
+    len = sizeof(path);
+    if (sysctl(name, 4, path, &len, NULL, 0) != 0)
+    {
+        return NULL;
+    }
+
+    return strdup(path);
+#elif defined(__sun)
+    const char* path = getexecname();
+    if (path == NULL)
+        return NULL;
+    return realpath(path, NULL);
+#else
+
+#ifdef __linux__
+    const char* symlinkEntrypointExecutable = "/proc/self/exe";
+#else
+    const char* symlinkEntrypointExecutable = "/proc/curproc/exe";
+#endif
+
+    // Resolve the symlink to the executable from /proc
+    return realpath(symlinkEntrypointExecutable, NULL);
+#endif
+}

src/libraries/Native/Unix/System.Native/pal_process.h

@@ -36,16 +36,6 @@ PALEXPORT int32_t SystemNative_ForkAndExecProcess(
                    int32_t* stdoutFd,      // [out] if redirectStdout, the parent's fd for the child's stdout
                    int32_t* stderrFd);     // [out] if redirectStderr, the parent's fd for the child's stderr
 
-/**
- * Shim for the popen function.
- */
-PALEXPORT FILE* SystemNative_POpen(const char* command, const char* type);
-
-/**
- * Shim for the pclose function.
- */
-PALEXPORT int32_t SystemNative_PClose(FILE* stream);
-
 /************
  * The values below in the header are fixed and correct for managed callers to use forever.
  * We must never change them. The implementation must either static_assert that they are equal
@@ -252,3 +242,9 @@ PALEXPORT int32_t SystemNative_SchedSetAffinity(int32_t pid, intptr_t* mask);
  */
 PALEXPORT int32_t SystemNative_SchedGetAffinity(int32_t pid, intptr_t* mask);
 #endif
+
+/**
+ * Returns the path of the executable that started the currently executing process, 
+ * resolving symbolic links. The caller is responsible for releasing the buffer.
+ */
+PALEXPORT char* SystemNative_GetProcessPath(void);

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

@@ -242,8 +242,6 @@
              Link="Common\Interop\Unix\Interop.ForkAndExecProcess.cs" />
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetGroupList.cs"
              Link="Common\Interop\Unix\Interop.GetGroupList.cs" />
-    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetLine.cs"
-             Link="Common\Interop\Unix\Interop.GetLine.cs" />
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetPwUid.cs"
              Link="Common\Interop\Unix\Interop.GetPwUid.cs" />
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetSetPriority.cs"
@@ -264,8 +262,6 @@
              Link="Common\Interop\Unix\Interop.ResourceLimits.cs" />
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.PathConf.cs"
              Link="Common\Interop\Unix\Interop.PathConf.cs" />
-    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.POpen.cs"
-             Link="Common\Interop\Unix\Interop.POpen.cs" />
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.WaitId.cs"
              Link="Common\Interop\Unix\Interop.WaitId.cs" />
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.WaitPid.cs"

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.FreeBSD.cs

@@ -101,12 +101,6 @@ private unsafe int ParentProcessId
             }
         }
 
-        /// <summary>Gets the path to the current executable, or null if it could not be retrieved.</summary>
-        private static string? GetExePath()
-        {
-            return Interop.Process.GetProcPath(Environment.ProcessId);
-        }
-
         // ----------------------------------
         // ---- Unix PAL layer ends here ----
         // ----------------------------------

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.OSX.cs

@@ -91,21 +91,6 @@ private int ParentProcessId
             }
         }
 
-        /// <summary>Gets the path to the current executable, or null if it could not be retrieved.</summary>
-        private static string? GetExePath()
-        {
-            try
-            {
-                return Interop.libproc.proc_pidpath(Environment.ProcessId);
-            }
-            catch (Win32Exception)
-            {
-                // It will throw System.ComponentModel.Win32Exception (2): No such file or Directory when
-                // the executable file is deleted.
-                return null;
-            }
-        }
-
         // ----------------------------------
         // ---- Unix PAL layer ends here ----
         // ----------------------------------

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.Unix.cs

@@ -680,7 +680,7 @@ private static string[] CreateEnvp(ProcessStartInfo psi)
             }
 
             // Then check the executable's directory
-            string? path = GetExePath();
+            string? path = Environment.ProcessPath;
             if (path != null)
             {
                 try

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.UnknownUnix.cs

@@ -76,11 +76,6 @@ private void SetWorkingSetLimitsCore(IntPtr? newMin, IntPtr? newMax, out IntPtr
             throw new PlatformNotSupportedException();
         }
 
-        private static string GetExePath()
-        {
-            throw new PlatformNotSupportedException();
-        }
-
         /// <summary>Gets execution path</summary>
         private string GetPathToOpenFile()
         {

src/libraries/System.Diagnostics.Process/tests/ProcessTests.cs

@@ -494,15 +494,10 @@ public void TestMainModule()
         {
             Process p = Process.GetCurrentProcess();
 
-            // On UAP casing may not match - we use Path.GetFileName(exePath) instead of kernel32!GetModuleFileNameEx which is not available on UAP
-            Func<string, string> normalize = PlatformDetection.IsInAppContainer ?
-                (Func<string, string>)((s) => s.ToLowerInvariant()) :
-                (s) => s;
-
             Assert.InRange(p.Modules.Count, 1, int.MaxValue);
-            Assert.Equal(normalize(RemoteExecutor.HostRunnerName), normalize(p.MainModule.ModuleName));
-            Assert.EndsWith(normalize(RemoteExecutor.HostRunnerName), normalize(p.MainModule.FileName));
-            Assert.Equal(normalize(string.Format("System.Diagnostics.ProcessModule ({0})", RemoteExecutor.HostRunnerName)), normalize(p.MainModule.ToString()));
+            Assert.Equal(RemoteExecutor.HostRunnerName, p.MainModule.ModuleName);
+            Assert.EndsWith(RemoteExecutor.HostRunnerName, p.MainModule.FileName);
+            Assert.Equal(string.Format("System.Diagnostics.ProcessModule ({0})", RemoteExecutor.HostRunnerName), p.MainModule.ToString());
         }
 
         [ConditionalFact(typeof(RemoteExecutor), nameof(RemoteExecutor.IsSupported))]

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -1380,6 +1380,9 @@
     <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.GetLongPathNameW.cs">
       <Link>Common\Interop\Windows\Kernel32\Interop.GetLongPathNameW.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.GetModuleFileName.cs">
+      <Link>Common\Interop\Windows\Kernel32\Interop.GetModuleFileName.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)Interop\Windows\Kernel32\Interop.GetProcessMemoryInfo.cs">
       <Link>Common\Interop\Windows\Kernel32\Interop.GetProcessMemoryInfo.cs</Link>
     </Compile>
@@ -1709,6 +1712,9 @@
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetHostName.cs">
       <Link>Common\Interop\Unix\System.Native\Interop.GetHostName.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetProcessPath.cs">
+      <Link>Common\Interop\Unix\System.Native\Interop.GetProcessPath.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.GetRandomBytes.cs">
       <Link>Common\Interop\Unix\System.Native\Interop.GetRandomBytes.cs</Link>
     </Compile>

src/libraries/System.Private.CoreLib/src/System/Environment.Browser.cs

@@ -25,6 +25,12 @@ private static OperatingSystem GetOSVersion()
             return new OperatingSystem(PlatformID.Other, new Version(1, 0, 0, 0));
         }
 
-        private static int GetCurrentProcessId() => 42;
+        private static int GetProcessId() => 42;
+
+        /// <summary>
+        /// Returns the path of the executable that started the currently executing process. Returns null when the path is not available.
+        /// </summary>
+        /// <returns>Path of the executable that started the currently executing process</returns>
+        private static string? GetProcessPath() => null;
     }
 }

src/libraries/System.Private.CoreLib/src/System/Environment.Unix.cs

@@ -4,6 +4,7 @@
 using System.Diagnostics;
 using System.IO;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
@@ -111,6 +112,10 @@ private static unsafe bool TryGetUserNameFromPasswd(byte* buf, int bufLen, out s
             throw new IOException(errorInfo.GetErrorMessage(), errorInfo.RawErrno);
         }
 
-        private static int GetCurrentProcessId() => Interop.Sys.GetPid();
+        [MethodImplAttribute(MethodImplOptions.NoInlining)] // Avoid inlining PInvoke frame into the hot path
+        private static int GetProcessId() => Interop.Sys.GetPid();
+
+        [MethodImplAttribute(MethodImplOptions.NoInlining)] // Avoid inlining PInvoke frame into the hot path
+        private static string? GetProcessPath() => Interop.Sys.GetProcessPath();
     }
 }