qga: Extract qmp_guest_file_read() to common commands.c

Extract the common code shared by both POSIX/Win32 implementations.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index cfaf6b8..9717a8d 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -322,33 +322,19 @@
     }
 }
 
-GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
-                                   int64_t count, Error **errp)
+GuestFileRead *guest_file_read_unsafe(GuestFileHandle *gfh,
+                                      int64_t count, Error **errp)
 {
     GuestFileRead *read_data = NULL;
     guchar *buf;
-    HANDLE fh;
+    HANDLE fh = gfh->fh;
     bool is_ok;
     DWORD read_count;
-    GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
 
-    if (!gfh) {
-        return NULL;
-    }
-    if (!has_count) {
-        count = QGA_READ_COUNT_DEFAULT;
-    } else if (count < 0 || count >= UINT32_MAX) {
-        error_setg(errp, "value '%" PRId64
-                   "' is invalid for argument count", count);
-        return NULL;
-    }
-
-    fh = gfh->fh;
     buf = g_malloc0(count + 1);
     is_ok = ReadFile(fh, buf, count, &read_count, NULL);
     if (!is_ok) {
         error_setg_win32(errp, GetLastError(), "failed to read file");
-        slog("guest-file-read failed, handle %" PRId64, handle);
     } else {
         buf[read_count] = 0;
         read_data = g_new0(GuestFileRead, 1);