Merge pull request #2974 from nguerrera/shim-pipe

Shim pipe and fcntl

src/Common/src/Interop/Unix/System.Native/Interop.Fcntl.cs

@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Sys
+    {
+        internal static class Fcntl
+        {
+            internal static readonly bool CanGetSetPipeSz = (FcntlCanGetSetPipeSz() != 0);
+
+            [DllImport(Libraries.SystemNative, EntryPoint="FcntlGetPipeSz", SetLastError=true)]
+            internal static extern int GetPipeSz(int fd);
+
+            [DllImport(Libraries.SystemNative, EntryPoint="FcntlSetPipeSz", SetLastError=true)]
+            internal static extern int SetPipeSz(int fd, int size);
+
+            [DllImport(Libraries.SystemNative)]
+            private static extern int FcntlCanGetSetPipeSz();
+        }
+    }
+}

src/Common/src/Interop/Unix/System.Native/Interop.Pipe.cs

@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class Sys
+    {
+        [Flags]
+        internal enum PipeFlags
+        {
+            O_CLOEXEC = 0x0010,
+        }
+
+        /// <summary>
+        /// The index into the array filled by <see cref="pipe"/> which represents the read end of the pipe.
+        /// </summary>
+        internal const int ReadEndOfPipe = 0;
+
+        /// <summary>
+        /// The index into the array filled by <see cref="pipe"/> which represents the read end of the pipe.
+        /// </summary>
+        internal const int WriteEndOfPipe = 1;
+
+        [DllImport(Libraries.SystemNative, SetLastError = true)]
+        internal static extern unsafe int Pipe(int* pipefd, PipeFlags flags = 0); // pipefd is an array of two ints
+    }
+}

src/Common/src/Interop/Unix/System.Native/Interop.Stat.cs

@@ -45,7 +45,7 @@ internal enum FileStatusFlags
         }
 
         [DllImport(Libraries.SystemNative, SetLastError = true)]
-        internal static extern int FStat(int fileDescriptor, out FileStatus output);
+        internal static extern int FStat(int fd, out FileStatus output);
 
         [DllImport(Libraries.SystemNative, SetLastError = true)]
         internal static extern int Stat(string path, out FileStatus output);

src/Common/src/Interop/Unix/System.Native/Interop.readdir.cs

@@ -48,7 +48,7 @@ internal struct DirectoryEntry
         private static unsafe extern int ReadDirR(SafeDirectoryHandle dir, byte* buffer, int bufferSize, out InternalDirectoryEntry outputEntry);
 
         [DllImport(Libraries.SystemNative, SetLastError = true)]
-        internal static extern int CloseDir(IntPtr directory);
+        internal static extern int CloseDir(IntPtr dir);
 
         // The calling pattern for ReadDir is described in src/Native/System.Native/pal_readdir.cpp
         internal static int ReadDir(SafeDirectoryHandle dir, out DirectoryEntry outputEntry)

src/Common/src/Interop/Unix/libcurl/Interop.SafeCurlHandle.cs

@@ -77,7 +77,7 @@ public SafeCurlMultiHandle()
                 {
                     fixed(int* fds = _specialFds)
                     {
-                        while (Interop.CheckIo(libc.pipe(fds)));
+                        while (Interop.CheckIo(Interop.Sys.Pipe(fds)));
                     }
                 }
             }
@@ -116,7 +116,7 @@ internal void PollFds(List<libc.pollfd> readyFds)
                     // is ready for a read/write. The special fd is the read end of a pipe
                     // Whenever an fd is added/removed in _fdSet, a write happens to the
                     // write end of the pipe thus causing the poll to return.
-                    pollFds[0].fd = _specialFds[libc.ReadEndOfPipe];
+                    pollFds[0].fd = _specialFds[Interop.Sys.ReadEndOfPipe];
                     pollFds[0].events = PollFlags.POLLIN;
                     int i = 1;
                     foreach (int fd in _fdSet)
@@ -186,7 +186,7 @@ internal void SignalFdSetChange(int fd, bool isRemove)
                 {
                     // Write to special fd
                     byte* dummyBytes = stackalloc byte[1];
-                    if ((int)libc.write(_specialFds[libc.WriteEndOfPipe], dummyBytes, (size_t)1) <= 0)
+                    if ((int)libc.write(_specialFds[Interop.Sys.WriteEndOfPipe], dummyBytes, (size_t)1) <= 0)
                     {
                         // TODO: How to handle errors?
                         throw new InvalidOperationException("Cannot write data: " + Marshal.GetLastWin32Error());
@@ -212,8 +212,8 @@ protected override bool ReleaseHandle()
                 Debug.Assert(0 == _requestCount);
                 Debug.Assert(_pollCancelled);
 
-                Interop.Sys.Close(_specialFds[libc.ReadEndOfPipe]);
-                Interop.Sys.Close(_specialFds[libc.WriteEndOfPipe]);
+                Interop.Sys.Close(_specialFds[Interop.Sys.ReadEndOfPipe]);
+                Interop.Sys.Close(_specialFds[Interop.Sys.WriteEndOfPipe]);
                 libcurl.curl_multi_cleanup(this.handle);
 
                 return true;
@@ -227,7 +227,7 @@ private int ReadSpecialFd(PollFlags revents)
                     return -1;
                 }
                 Debug.Assert((revents & PollFlags.POLLIN) != 0);
-                int pipeReadFd = _specialFds[libc.ReadEndOfPipe];
+                int pipeReadFd = _specialFds[Interop.Sys.ReadEndOfPipe];
                 int bytesRead = 0;
                 unsafe
                 {

src/Native/System.Native/pal_io.cpp

@@ -97,10 +97,10 @@ int32_t Stat(const char* path, FileStatus* output)
 }
 
 extern "C"
-int32_t FStat(int32_t fileDescriptor, FileStatus* output)
+int32_t FStat(int32_t fd, FileStatus* output)
 {
     struct stat_ result;
-    int ret = fstat_(fileDescriptor, &result);
+    int ret = fstat_(fd, &result);
 
     if (ret == 0)
     {
@@ -185,9 +185,9 @@ int32_t Open(const char* path, int32_t flags, int32_t mode)
 }
 
 extern "C"
-int32_t Close(int32_t fileDescriptor)
+int32_t Close(int32_t fd)
 {
-    return close(fileDescriptor);
+    return close(fd);
 }
 
 extern "C"
@@ -215,7 +215,6 @@ int32_t ShmUnlink(const char* name)
     return shm_unlink(name);
 }
 
-
 static
 void ConvertDirent(const dirent& entry, DirectoryEntry* outputEntry)
 {
@@ -299,7 +298,62 @@ DIR* OpenDir(const char* path)
 }
 
 extern "C" 
-int32_t CloseDir(DIR* directory)
+int32_t CloseDir(DIR* dir)
+{
+    return closedir(dir);
+}
+
+extern "C"
+int32_t Pipe(int32_t pipeFds[2], int32_t flags)
 {
-    return closedir(directory);
+    switch (flags)
+    {
+    case 0:
+        break;
+    case PAL_O_CLOEXEC:
+        flags = O_CLOEXEC;
+        break;
+    default:
+        assert(!"Unknown flag.");
+        errno = EINVAL;
+        return -1;
+    }
+
+#if HAVE_PIPE2
+    return pipe2(pipeFds, flags);
+#else
+    return pipe(pipeFds); // CLOEXEC intentionally ignored on platforms without pipe2.
+#endif
+}
+
+extern "C"
+int32_t FcntlCanGetSetPipeSz()
+{
+#if defined(F_GETPIPE_SZ) && defined(F_SETPIPE_SZ)
+    return true;
+#else
+    return false;
+#endif
+}
+
+extern "C"
+int32_t FcntlGetPipeSz(int32_t fd)
+{
+#ifdef F_GETPIPE_SZ
+    return fcntl(fd, F_GETPIPE_SZ);
+#else
+    errno = ENOTSUP;
+    return -1;
+#endif
+}
+
+extern "C"
+int32_t FcntlSetPipeSz(int32_t fd, int32_t size)
+{
+#ifdef F_SETPIPE_SZ
+    return fcntl(fd, F_SETPIPE_SZ, size);
+#else
+    errno = ENOTSUP;
+    return -1;
+#endif
 }

src/Native/System.Native/pal_io.h

@@ -129,7 +129,7 @@ struct DirectoryEntry
  */
 extern "C"
 int32_t FStat(
-    int32_t fileDescriptor,
+    int32_t fd,
     FileStatus* output);
 
 /**
@@ -160,7 +160,7 @@ int32_t LStat(
 extern "C"
 int32_t Open(
     const char* path,
-    int32_t oflag,
+    int32_t flags,
     int32_t mode);
 
 /**
@@ -170,8 +170,8 @@ int32_t Open(
  */
 extern "C"
 int32_t Close(
-    int32_t fileDescriptor);
-    
+    int32_t fd);
+
 /**
  * Delete an entry from the file system. Implemented as shim to unlink(2).
  *
@@ -180,17 +180,17 @@ int32_t Close(
 extern "C"
 int32_t Unlink(
     const char* path);
-    
+
 /**
  * Open or create a shared memory object. Implemented as shim to shm_open(3).
  *
  * Returns file descriptor or -1 on fiailure. Sets errno on failure.
  */
 extern "C"
 int32_t ShmOpen(
-     const char* name,
-     int32_t oflag,
-     int32_t mode);
+    const char* name,
+    int32_t flags,
+    int32_t mode);
 
 /**
  * Unlink a shared memory object. Implemented as shim to shm_unlink(3).
@@ -223,10 +223,59 @@ int32_t ReadDirR(
  * Returns a DIR struct containing info about the current path or NULL on failure; sets errno on fail.
  */
 extern "C"
-DIR* OpenDir(const char* path);
+DIR* OpenDir(
+    const char* path);
 
 /**
  * Closes the directory stream opened by opendir and returns 0 on success. On fail, -1 is returned and errno is set
  */
 extern "C"
-int32_t CloseDir(DIR* directory);
+int32_t CloseDir(
+    DIR* dir);
+
+/**
+ * Creates a pipe. Implemented as shim to pipe(2) or pipe2(2) if available.
+ * Flags are ignored if pipe2 is not available.
+ *
+ * Returns 0 for success, -1 for failure. Sets errno on failure.
+ */
+extern "C"
+int32_t Pipe(
+    int32_t pipefd[2], // [out] pipefds[0] gets read end, pipefd[1] gets write end.
+    int32_t flags);    // 0 for defaults or PAL_O_CLOEXEC for close-on-exec
+
+
+// NOTE: Rather than a general fcntl shim, we opt to export separate functions 
+// for each command. This allows use to have strongly typed arguments and saves
+// complexity around converting command codes.
+
+/**
+ * Determines if the current platform supports getting and setting pipe capacity.
+ *
+ * Returns true (non-zero) if supported, false (zero) if not.
+ */
+extern "C"
+int32_t FcntlCanGetSetPipeSz();
+
+/**
+ * Gets the capacity of a pipe.
+ *
+ * Returns the capacity or -1 with errno set aprropriately on failure.
+ *
+ * NOTE: Some platforms do not support this operation and will always fail with errno = ENOTSUP.
+ */
+extern "C"
+int32_t FcntlGetPipeSz(
+    int32_t fd);
+
+/**
+ * Sets the capacity of a pipe.
+ *
+ * Returns 0 for success, -1 for failure. Sets errno for failure.
+ *
+ * NOTE: Some platforms do not support this operation and will always fail with errno = ENOTSUP.
+ */
+extern "C"
+int32_t FcntlSetPipeSz(
+    int32_t fd,
+    int32_t size);