From b8349218955ffbb2b573a2de8efac61a800f4eb0 Mon Sep 17 00:00:00 2001 From: Corinna Vinschen Date: Fri, 24 Apr 2020 16:19:09 +0200 Subject: [PATCH] Cygwin: raw disk I/O: Fix return value in error case The cast to generate the return value uses a DWORD variable as test and set value. The error case is the constant -1. Given the type of the other half of the conditioal expression, -1 is cast to DWORD as well. On 64 bit, this results in the error case returning a 32 bit -1 value which is equivalent to (ssize_t) 4294967295 rather than (ssize_t) -1. Add a fixing cast. Signed-off-by: Corinna Vinschen --- winsup/cygwin/fhandler_floppy.cc | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/winsup/cygwin/fhandler_floppy.cc b/winsup/cygwin/fhandler_floppy.cc index f2e15d703..778d6ef98 100644 --- a/winsup/cygwin/fhandler_floppy.cc +++ b/winsup/cygwin/fhandler_floppy.cc @@ -619,12 +619,12 @@ fhandler_dev_floppy::raw_write (const void *ptr, size_t len) devbufend = bytes_per_sector; } } - return bytes_written; + return (ssize_t) bytes_written; } /* In O_DIRECT case, just write. */ if (write_file (p, len, &bytes_written, &ret)) - return bytes_written; + return (ssize_t) bytes_written; err: if (IS_EOM (ret)) @@ -635,7 +635,8 @@ err: } else if (!bytes_written) __seterrno (); - return bytes_written ?: -1; + /* Cast is required, otherwise the error return value is (DWORD)-1. */ + return (ssize_t) bytes_written ?: -1; } off_t