Date: Tue, 3 Dec 2019 22:15:52 +0100 From: Vincenzo Maffione <vmaffione@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: Ian Lepore <ian@freebsd.org>, Rodney Grimes <rgrimes@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r355301 - head/usr.sbin/bhyve Message-ID: <CA%2B_eA9gvY-1wtGZHp816n3WW3iU9Ti96Lkks5DhpMUNJGtQ1YQ@mail.gmail.com> In-Reply-To: <d22ae631-e9c9-1ea9-9adc-a162f17e0b11@FreeBSD.org> References: <201912030722.xB37MdrZ033595@gndrsh.dnsmgr.net> <8044a2f1096df626368183dd1ae77f5ac2e43b70.camel@freebsd.org> <d22ae631-e9c9-1ea9-9adc-a162f17e0b11@FreeBSD.org>
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I see, thanks for the pointers. It looks like cfmakeraw() and tcsetattr() were what I was looking for. A bhyve-specific printf wrapper looks the right solution to me. I can try to sketch a patch for you guys to review, if that's useful. Cheers, Vincenzo Il giorno mar 3 dic 2019 alle ore 18:38 John Baldwin <jhb@freebsd.org> ha scritto: > On 12/3/19 7:14 AM, Ian Lepore wrote: > > On Mon, 2019-12-02 at 23:22 -0800, Rodney W. Grimes wrote: > >>> On Mon, 2019-12-02 at 20:51 +0000, Vincenzo Maffione wrote: > >>>> Author: vmaffione > >>>> Date: Mon Dec 2 20:51:46 2019 > >>>> New Revision: 355301 > >>>> URL: https://svnweb.freebsd.org/changeset/base/355301 > >>>> > >>>> Log: > >>>> bhyve: uniform printf format string newlines > >>>> > >>>> Some of the printf statements only use LF to get a newline. > >>>> However, a CR character is also required for the serial console to > >>>> print debug logs in a nice way. > >>>> Fix those code locations that only use LF, by adding a CR > >>>> character. > >>>> > >>>> Reviewed by: markj, aleksandr.fedorov@itglobal.com > >>>> MFC after: 1 week > >>>> Differential Revision: https://reviews.freebsd.org/D22552 > >>>> > >>>> Modified: > >>>> head/usr.sbin/bhyve/audio.c > >>>> head/usr.sbin/bhyve/hda_codec.c > >>>> head/usr.sbin/bhyve/net_backends.c > >>>> head/usr.sbin/bhyve/pci_ahci.c > >>>> head/usr.sbin/bhyve/pci_e82545.c > >>>> head/usr.sbin/bhyve/pci_hda.c > >>>> head/usr.sbin/bhyve/pci_nvme.c > >>>> head/usr.sbin/bhyve/pci_virtio_block.c > >>>> head/usr.sbin/bhyve/pci_virtio_console.c > >>>> head/usr.sbin/bhyve/pci_virtio_net.c > >>>> head/usr.sbin/bhyve/pci_virtio_rnd.c > >>>> head/usr.sbin/bhyve/pci_virtio_scsi.c > >>>> head/usr.sbin/bhyve/pci_xhci.c > >>>> head/usr.sbin/bhyve/rfb.c > >>>> > >>> > >>> These changes seem wrong in a couple ways... > >>> > >>> - Lines are terminated by linefeeds in unix-like systems. If > >>> linefeeds need to be translated to include carriage returns, that's the > >>> responsibility of the terminal/line-discipline layer, not the source > >>> strings being printed. > >> > >> Fully agree, this change seems wrong to me for Ian's stated reason here. > >> > >>> > >>> - The sequence \n\r is very strange. For systems that do prefer > >>> carriage returns, the \r always comes before the \n (or stands alone on > >>> Mac systems), not after. > >>> > >>> I have a feeling that the root of this is something like "lots of > >>> people use bhyve for Windows, so they use Windows apps to look at logs, > >>> so the logs should be formatted for Windows." If that's the reasoning, > >>> then why shouldn't we convert EVERY printf in the source base to > >>> include carriage returns, just in case a windows user wants to browse a > >>> log file? > >> > >> This is not that issue, it is something going on with the line > >> discipline when using the bhyve console device. I believe the > >> line displine being different from what bhyve itself is expecting > >> so when console output is intermixed with output from bhyve itself > >> things go wrong. > >> > >> The printf's in this patch are coming from the bhyve process that > >> has a fd open to the launching tty, the line discipline on that tty > >> is changed to something different after you open the > >> console device from that same controlling tty, or that is my hypothosis > >> on what is going wrong. > > > > There is a cfmakeraw() call in usr.sbin/bhyve/consport.c; that would > > definitely turn off nl->crnl translations. I think that is the other > > end of the bhyve console that I posted a patch for yesterday, and I > > think the console driver is probably still the right place to do that > > translation (because other console drivers do it that way). But I'm > > not set up to run bhyve here, so I can't test my theory. > > That patch won't work alone. Most people don't use bvmcons, most people > running bhyve use a standard uart as the console (bvmcons was an early > console devices before bhyve had a ns8250 uart device model). When using > the uart as the device model you still have raw output in the bhyve > process itself. (See cfmakeraw() in uart_emul.c as well). We don't > get to change how guest OS's use a uart, so any changes have to be in > usr.sbin/bhyve, not in sys/. > > However, to do that you have to actually do something more complicated to > turn \r\n and \n\r sequences from the guest into plain \n to stdout while > still DTRT for "bare" \r and \n characters. You also have to make sure > you do the right thing for input and not just output in the device models. > > I'm not quite a fan of this commit as-is since you will get spurious new > lines now if you don't use a serial console. I would perhaps rather have > a custom printf() wrapper in bhyve that outputs the \r as needed for > debug and error printfs only when stdio has been changed to be raw. I > was busy with family stuff and thanksgiving last week so didn't have time > to review it before it was committed unfortunately. > > -- > John Baldwin >
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