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Re: ctrl-c doesn't reliably kill ping
- From: Warren Young <wyml at etr-usa dot com>
- To: The Cygwin Mailing List <cygwin at cygwin dot com>
- Date: Wed, 16 Mar 2016 10:50:47 -0600
- Subject: Re: ctrl-c doesn't reliably kill ping
- Authentication-results: sourceware.org; auth=none
- References: <56E6F25A dot 7070000 at gmx dot de> <56E75B3E dot 7020102 at farance dot com> <CAD8GWstL-rUm9=q8tpReiiHm8Tmm94Caq7jQyszZ02Tw=EN_TQ at mail dot gmail dot com>
On Mar 16, 2016, at 10:07 AM, Lee <email@example.com> wrote:
> The last time I tried the cygwin ping program it didn't return a
> failure status
It does if you donât Ctrl-C out of it. So, if youâre using it from a script, you just ask for one packet:
# ping does.not.exist 1 1
ping: unknown host does.not.exist
# echo $?
Note my fine new # prompt, indicating an admin shell, which has been required for Cygwin ping from the very beginning due to the restrictions on raw sockets added in Windows XP SP2. Windows ping gets around this by special dispensation of the kernel.
If you want to say Cygwin ping is âuselessâ because of that, blame Microsoft for not allowing ICMP raw sockets for normal users  or for not reinventing suid bits correctly. (UAC = not correct.)
Older Linuxes and some modern Unixes set the suid bit on the ping program to get around this, and newer Linuxes use getcap/setcap to give the ping program the right to use raw sockets so they donât need u+s.
 It loads IPHLPAPI.DLL at run time in order to call IcmpSendEcho()
Problem reports: http://cygwin.com/problems.html
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