[PATCH] pread() returns non-zero if read beyond EOF, because NtReadFile returns EOF status but doesn't set information to 0. Need reset io status block before NtReadFile is called, so that pread() will return 0 if read beyond EOF.

Xiaofeng Liu via cygwin-patches cygwin-patches@cygwin.com
Wed Nov 8 17:02:00 GMT 2017


 Hi Corinna,The followup patch is different from  https://sourceware.org/git/?p=newlib-cygwin.git;a=commitdiff;h=46702f92ea49Maybe I missed the submit protocol?ThanksXiaofeng
    On Wednesday, November 8, 2017, 4:41:22 AM PST, Corinna Vinschen <corinna-cygwin@cygwin.com> wrote:  
 
 On Nov  8 13:34, Corinna Vinschen wrote:
> On Nov  7 17:33, Xiaofeng Liu via cygwin-patches wrote:
> > --- winsup/cygwin/fhandler_disk_file.cc |    1 + 1 files changed, 1 insertions(+), 0 deletions(-)
> > diff --git a/winsup/cygwin/fhandler_disk_file.cc b/winsup/cygwin/fhandler_disk_file.ccindex bc8fead..525cb32 100644--- a/winsup/cygwin/fhandler_disk_file.cc+++ b/winsup/cygwin/fhandler_disk_file.cc@@ -1525,6 +1525,7 @@ fhandler_disk_file::pread (void *buf, size_t count, off_t offset)       IO_STATUS_BLOCK io;       LARGE_INTEGER off = { QuadPart:offset }; +      memset(&io, 0, sizeof(io));       if (!prw_handle && prw_open (false))        goto non_atomic;       status = NtReadFile (prw_handle, NULL, NULL, NULL, &io, buf, count,-- 1.7.1
> 
> This is still completely broken, unfortunately.  I took a look, though,
> and fixed this problem slightly differently.  Please have a look at
> https://sourceware.org/git/?p=newlib-cygwin.git;a=commitdiff;h=46702f92ea49
> I retained your authorship, of course.

Obvious followup patch:

https://sourceware.org/git/?p=newlib-cygwin.git;a=commitdiff;h=181fe5d2ed


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                cygwin AT cygwin DOT com
Red Hat  


More information about the Cygwin-patches mailing list