[UCRT] Import Microsoft.Windows.SDK.CRTSource version 10.0.22621.3

Imported from https://www.nuget.org/packages/Microsoft.Windows.SDK.CRTSource/10.0.22621.3
License: MIT

sdk/lib/ucrt/lowio/chsize.cpp

@@ -0,0 +1,148 @@
+//
+// chsize.cpp
+//
+//      Copyright (c) Microsoft Corporation. All rights reserved.
+//
+// Defines _chsize() and _chsize_s(), which change the size of a file.
+//
+#include <corecrt_internal_lowio.h>
+#include <corecrt_internal_ptd_propagation.h>
+
+
+// Changes the size of the given file, either extending or truncating it.  The
+// file must have been opened with write permissions or this will fail.  Returns
+// 0 on success; returns an errno error code on failure,
+static errno_t __cdecl _chsize_s_internal(int const fh, __int64 const size, __crt_cached_ptd_host& ptd)
+{
+    _UCRT_CHECK_FH_CLEAR_OSSERR_RETURN_ERRCODE(ptd, fh, EBADF);
+    _UCRT_VALIDATE_CLEAR_OSSERR_RETURN_ERRCODE(ptd, (fh >= 0 && (unsigned)fh < (unsigned)_nhandle), EBADF);
+    _UCRT_VALIDATE_CLEAR_OSSERR_RETURN_ERRCODE(ptd, (_osfile(fh) & FOPEN), EBADF);
+    _UCRT_VALIDATE_CLEAR_OSSERR_RETURN_ERRCODE(ptd, (size >= 0), EINVAL);
+
+    return __acrt_lowio_lock_fh_and_call(fh, [&]()
+    {
+        if (_osfile(fh) & FOPEN)
+        {
+            return _chsize_nolock_internal(fh, size, ptd);
+        }
+        else
+        {
+            _ASSERTE(("Invalid file descriptor. File possibly closed by a different thread", 0));
+            return ptd.get_errno().set(EBADF);
+        }
+    });
+}
+
+extern "C" errno_t __cdecl _chsize_s(int const fh, __int64 const size)
+{
+    __crt_cached_ptd_host ptd;
+    return _chsize_s_internal(fh, size, ptd);
+}
+
+struct __crt_seek_guard
+{
+
+    __crt_seek_guard(int const fh, __int64 const size)
+        : place(_lseeki64_nolock(fh, 0, SEEK_CUR)),
+        end(_lseeki64_nolock(fh, 0, SEEK_END)),
+        extend(size - end),
+        fhh(fh)
+    {
+    }
+
+    ~__crt_seek_guard()
+    {
+        _lseeki64_nolock(fhh, place, SEEK_SET);
+    }
+
+    __crt_seek_guard(__crt_seek_guard const &) = delete;
+    __crt_seek_guard& operator=(__crt_seek_guard const &) = delete;
+
+    __int64 place;
+    __int64 end;
+    __int64 extend;
+    int fhh;
+};
+
+extern "C" errno_t __cdecl _chsize_nolock_internal(int const fh, __int64 const size, __crt_cached_ptd_host& ptd)
+{
+    // Get current file position and seek to end
+    __crt_seek_guard seek_guard(fh, size);
+
+    if (seek_guard.place == -1 || seek_guard.end == -1)
+    {
+        // EBADF if earlier lseek (in __crt_seek_guard) failed
+        // EINVAL otherwise (ex: too large of a offset)
+        return ptd.get_errno().value_or(EINVAL);
+    }
+
+    // Grow or shrink the file as necessary:
+    if (seek_guard.extend > 0)
+    {
+        // Extend the file by filling the new area with zeroes:
+        __crt_unique_heap_ptr<char> const zero_buffer(_calloc_crt_t(char, _INTERNAL_BUFSIZ));
+        if (!zero_buffer)
+        {
+            return ptd.get_errno().set(ENOMEM);
+        }
+
+        int const old_mode = _setmode_nolock(fh, _O_BINARY);
+
+        do
+        {
+            int const bytes_to_write = seek_guard.extend >= static_cast<__int64>(_INTERNAL_BUFSIZ)
+                ? _INTERNAL_BUFSIZ
+                : static_cast<int>(seek_guard.extend);
+
+            int const bytes_written = _write_nolock(fh, zero_buffer.get(), bytes_to_write, ptd);
+            if (bytes_written == -1)
+            {
+                // Error on write:
+                if (ptd.get_doserrno().check(ERROR_ACCESS_DENIED))
+                {
+                    ptd.get_errno().set(EACCES);
+                }
+
+                return ptd.get_errno().value_or(0);
+            }
+
+            seek_guard.extend -= bytes_written;
+        } while (seek_guard.extend > 0);
+
+#pragma warning(suppress:6031) // return value ignored
+        _setmode_nolock(fh, old_mode);
+    }
+    else if (seek_guard.extend < 0)
+    {
+        // Shorten the file by truncating it:
+        __int64 const new_end = _lseeki64_nolock(fh, size, SEEK_SET);
+        if (new_end == -1)
+        {
+            return ptd.get_errno().value_or(0);
+        }
+
+        if (!SetEndOfFile(reinterpret_cast<HANDLE>(_get_osfhandle(fh))))
+        {
+            ptd.get_doserrno().set(GetLastError());
+            return ptd.get_errno().set(EACCES);
+        }
+    }
+
+    return 0;
+}
+
+extern "C" errno_t __cdecl _chsize_nolock(int const fh, __int64 const size)
+{   // TODO: _chsize_nolock is already internal-only.
+    // Once PTD is propagated everywhere, rename _chsize_nolock_internal to _chsize_nolock.
+    __crt_cached_ptd_host ptd;
+    return _chsize_nolock_internal(fh, size, ptd);
+}
+
+
+// Changes the size of the given file, either extending or truncating it.  The
+// file must have been opened with write permissions or this will fail.  Returns
+// 0 on success; returns -1 and sets errno on failure.
+extern "C" int __cdecl _chsize(int const fh, long const size)
+{
+    return _chsize_s(fh, size) == 0 ? 0 : -1;
+}