Date: Sat, 9 Jan 2021 20:47:38 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Vasily Postnicov <shamaz.mazum@gmail.com> Cc: Mark Johnston <markj@freebsd.org>, freebsd-net@freebsd.org Subject: Re: DNS using Name Service Switch module and Casper Message-ID: <X/n6SkWSXOtb0DBY@kib.kiev.ua> In-Reply-To: <CADnZ6Bn0gVrGLu0_KsY_m-okL8WNU__E7WCYr5DppHubm90Byw@mail.gmail.com> References: <CADnZ6Bke=9%2B_pMc6rkbheNUWS-H6_X14%2Bf%2BWz5cfUCD=BTwk=g@mail.gmail.com> <X/R7Ahz8sz5v%2BoFa@raichu> <CADnZ6BmUJxVZx155j8opJKNsHJBE5mWz9D=MBE0Y_xu-kgOBfQ@mail.gmail.com> <X/h%2BJRmXmrOfmXBM@raichu> <CADnZ6Bm96bjJN5gcpCWiNKbNou3XvxZmCD2-YbX34%2B00L=UdPw@mail.gmail.com> <CADnZ6B=nFt-a-0CX=sCDnEM_CjnDQmiotyZ9L6q6jTZ0qJ-FVQ@mail.gmail.com> <CADnZ6Bm49RBuku%2BrN2cH75p89ByARXxP5BKAH89g2TrQars5VA@mail.gmail.com> <X/ndxoPtkWs%2BOPij@raichu> <CADnZ6Bn0gVrGLu0_KsY_m-okL8WNU__E7WCYr5DppHubm90Byw@mail.gmail.com>
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On Sat, Jan 09, 2021 at 08:25:46PM +0300, Vasily Postnicov wrote: > Brilliant! It took me almost a day to dive into ZeroMQ to reassure > myself that there is nothing wrong with it. When I tried to write > minimal test programs which call fork after pthread_create() in all > combinations. When I realized that NSS stub module is what I need. > > Instructions: > > 1) Compile NSS stub module: cc -shared -fPIC -pthread -o > nss_zerodns.so.1 test.c (Note '.1' at the end). > 2) Copy nss_zerodns.so.1 to /usr/local/lib > 3) Apply the patch src_sbin_ping_main.c to ping source code. With this > patch ping will not quit too early when the initial call to > getaddrinfo() fails. > 4) Add stub module to /etc/nsswitch.conf: edit 'hosts' line to be > 'hosts: files dns zerodns' > 5) Ping non-existent host, like 'ping foo.bar' > 6) Ping will hang. The child process which it creates cannot be killed > even with killall -9 ping This is exactly what I do not want. Provide a standalone binary (or binaries) that can be just run and demonstrate the issue. Without editing nsswitch.conf or patching ping.
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