Do not use read() and write() from MSVCRT

[wimlib] / src / win32_replacements.c

diff --git a/src/win32_replacements.c b/src/win32_replacements.c
index 05b07db98892e58376d75e6412253728471245f4..26f4b4b7969398ea7c6b81adb696d803703cbcd5 100644 (file)
--- a/src/win32_replacements.c
+++ b/src/win32_replacements.c
@@ -483,13 +483,15 @@ win32_strerror_r_replacement(int errnum, wchar_t *buf, size_t buflen)
        return 0;
 }
 
+#define MAX_IO_AMOUNT 1048576
+
 static int
 do_pread_or_pwrite(int fd, void *buf, size_t count, off_t offset,
                   bool is_pwrite)
 {
        HANDLE h;
        LARGE_INTEGER orig_offset;
-       DWORD bytes_read_or_written;
+       DWORD result = 0xFFFFFFFF;
        LARGE_INTEGER relative_offset;
        OVERLAPPED overlapped;
        BOOL bret;
@@ -517,10 +519,12 @@ do_pread_or_pwrite(int fd, void *buf, size_t count, off_t offset,
        overlapped.OffsetHigh = offset >> 32;
 
        /* Do the read or write at the specified offset */
+       count = min(count, MAX_IO_AMOUNT);
+       SetLastError(0);
        if (is_pwrite)
-               bret = WriteFile(h, buf, count, &bytes_read_or_written, &overlapped);
+               bret = WriteFile(h, buf, count, &result, &overlapped);
        else
-               bret = ReadFile(h, buf, count, &bytes_read_or_written, &overlapped);
+               bret = ReadFile(h, buf, count, &result, &overlapped);
        if (!bret) {
                err = GetLastError();
                win32_error(err, L"Failed to %s %zu bytes at offset %"PRIu64,
@@ -528,6 +532,8 @@ do_pread_or_pwrite(int fd, void *buf, size_t count, off_t offset,
                goto error;
        }
 
+       wimlib_assert(result <= count);
+
        /* Restore the original position */
        if (!SetFilePointerEx(h, orig_offset, NULL, FILE_BEGIN)) {
                err = GetLastError();
@@ -536,7 +542,7 @@ do_pread_or_pwrite(int fd, void *buf, size_t count, off_t offset,
                goto error;
        }
 
-       return bytes_read_or_written;
+       return result;
 
 error:
        if (err)
@@ -548,7 +554,7 @@ error:
  * offset, so it is not safe to use with readers/writers on the same file
  * descriptor.  */
 ssize_t
-pread(int fd, void *buf, size_t count, off_t offset)
+win32_pread(int fd, void *buf, size_t count, off_t offset)
 {
        return do_pread_or_pwrite(fd, buf, count, offset, false);
 }
@@ -557,11 +563,59 @@ pread(int fd, void *buf, size_t count, off_t offset)
  * offset, so it is not safe to use with readers/writers on the same file
  * descriptor. */
 ssize_t
-pwrite(int fd, const void *buf, size_t count, off_t offset)
+win32_pwrite(int fd, const void *buf, size_t count, off_t offset)
 {
        return do_pread_or_pwrite(fd, (void*)buf, count, offset, true);
 }
 
+/* Replacement for read() which doesn't hide the Win32 error code */
+ssize_t
+win32_read(int fd, void *buf, size_t count)
+{
+       HANDLE h = (HANDLE)_get_osfhandle(fd);
+       DWORD result = 0xFFFFFFFF;
+
+       if (h == INVALID_HANDLE_VALUE)
+               return -1;
+
+       count = min(count, MAX_IO_AMOUNT);
+       SetLastError(0);
+       if (!ReadFile(h, buf, count, &result, NULL)) {
+               DWORD err = GetLastError();
+               win32_error(err,
+                           L"Error reading %zu bytes from fd %d", count, fd);
+               set_errno_from_win32_error(err);
+               return -1;
+       }
+
+       wimlib_assert(result <= count);
+       return result;
+}
+
+/* Replacement for write() which doesn't hide the Win32 error code */
+ssize_t
+win32_write(int fd, const void *buf, size_t count)
+{
+       HANDLE h = (HANDLE)_get_osfhandle(fd);
+       DWORD result = 0xFFFFFFFF;
+
+       if (h == INVALID_HANDLE_VALUE)
+               return -1;
+
+       count = min(count, MAX_IO_AMOUNT);
+       SetLastError(0);
+       if (!WriteFile(h, buf, count, &result, NULL)) {
+               DWORD err = GetLastError();
+               win32_error(err,
+                           L"Error writing %zu bytes to fd %d", count, fd);
+               set_errno_from_win32_error(err);
+               return -1;
+       }
+
+       wimlib_assert(result <= count);
+       return result;
+}
+
 /* Replacement for glob() in Windows native builds that operates on wide
  * characters.  */
 int