TUHS

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6419 discussions

Re: [TUHS] 8th Edition Research Unix on SIMH

by norman＠oclsc.org

Tim Newsham: I'm not sure what fd 3 is intended to be, but its the telnet socket in p9p. ==== By the 10/e days, file descriptor 3 was /dev/tty. There was no more magic driver for /dev/tty; the special file still existed, but it was a link to /dev/fd/3. Similarly /dev/stdin stdout stderr were links to /dev/fd/0 1 2. (I mean real links, not mere symbolic ones.) I have a vague recollection that early on /dev/tty was fd/127 instead, but that changed somewhere in the middle 8/e era. None of which says what Plan 9 did with that file descriptor, though I suppose it could possibly have copied the /dev/tty use. And none of that excuses the hard-coded magic number file descriptor, but hackers will be hackers. Norman Wilson Toronto ON

7 years, 9 months

8th Edition Research Unix on SIMH

by David du Colombier

Here are my notes to run 8th Edition Research Unix on SIMH. http://9legacy.org/9legacy/doc/simh/v8 These notes are quite raw and unpolished, but should be sufficient to get Unix running on SIMH. Fell free to use, improve and share. -- David du Colombier

7 years, 9 months

Re: [TUHS] was turmoil, moving to rm -rf /

by David

Many years ago I was at Burroughs and they wanted to do Unix (4.1c) on a new machine. Fine. We all started on the project porting from a Vax. So far so good. Then a new PM came in and said that intel was the future and we needed to use their machines for the host of the port. And an intel rep brought in their little x86 box running some version of Unix (Xenix?, I didn’t go anywhere near the thing). My boss, who was running the Unix port project did the following: Every Friday evening he would log into the intel box as root and run “/bin/rm -rf /“ from the console. Then turn off the console and walk away. Monday morning found the box dead and the intel rep would be called to come and ‘fix’ his box. This went on for about 4 weeks, and finally my boss asked the intel rep what was wrong with his machine. The rep replied that this was ‘normal’ for the hardware/software and we would just have to “get used to it”. The PM removed the intel box a couple of days later. David > On Apr 25, 2017, at 7:19 AM, tuhs-request(a)minnie.tuhs.org wrote: > > From: Larry McVoy <lm(a)mcvoy.com> > To: Clem Cole <clemc(a)ccc.com> > Cc: Larry McVoy <lm(a)mcvoy.com>, TUHS main list <tuhs(a)minnie.tuhs.org> > Subject: Re: [TUHS] was turmoil, moving to rm -rf / > Message-ID: <20170425140853.GD24499(a)mcvoy.com> > Content-Type: text/plain; charset=us-ascii > > Whoever was the genuis that put mknod in /etc has my gratitude. > We had other working Masscomp boxen but after I screwed up that > badly nobody would let me near them until I fixed mine :) > > And you have to share who it was, I admitted I did it, I think > it's just a thing many people do..... Once :)

7 years, 9 months

Apple Darwin 0.1 and 0.3 sort of running on x86!

by Jason Stevens

I don't know if this is of any interest to anyone here, but 1999 is 18 years ago, so maybe it counts as old? Over on nextcomputers.org various users had found a backup of next68k.org which included a wget of the old source http://nextftp.onionmixer.net/next.68k.org/otto/html/pub/Darwin/PublicSource /Darwin/index.html So I found a copy of Rhapsody DR-2, the last binary version of this Mach 2.5+4.4BSD and after a day got a kernel to build. Another day and I had it interfacing to the driverkit to load drivers. After a post on reddit someone gave me a link to some kdx p2p network, where they had a Darwin 0.3 toast image. using what I learned with Darwin 0.1 I got the 0.3 to build as well. I uploaded a bunch of stuff here: https://sourceforge.net/projects/aapl-darwin/ although it seems to not let me upload the toast images themselves. I did slam together a minimal Darwin 0.3 qemu image that can sort-of boot to single user mode. It's not even slightly useful, but it does show that it works. https://sourceforge.net/projects/aapl-darwin/files/qemu-images/Darwin03_qemu 090_24_4_2017.7z/download

7 years, 9 months

Re: [TUHS] There is turmoil in Linux-land - When did rm first avoid going upwards?

by jnc＠mercury.lcs.mit.edu

> From: Kurt H Maier > /etc/glob, which appears to report no-match if the first character is . So I couldn't be bothered to work out how 'glob' worked exactly, so I just did an experiment: I created a hacked version of 'rm' that had the directory handling call to glob call 'echo' instead of 'rm'; it also printed 'tried' instead of the actual unlink call, and printed 'cd' when it changed directories. I then set up two subsidiary directors, foo and .bar, with one containing '.foo0 foo1' and the other '.bar0 bar1'. Saying 'xrm -r -f .*' produced this: cd: . -r -f foo xrm xrm.c cd: .. -r -f foo xrm xrm.c cd: .bar -r -f bar1 (This system has /tmp on a mounted file system, which is why the 'cd ..' was a NOP. And a very good thing, too; at one point the phone rang, and it distracted me, and I automatically typed 'rm', not 'xrm'... see below for what happened. No biggie, there were only my test files there. The output lines are "-r -f foo xrm xrm.c" because that's what 'glob' passed to 'echo'.) Saying 'xrm -r -f *' produced this: cd: foo -r -f foo1 xrm: tried xrm.c: tried So apparently 'glob', when presented with '*' , ignores entries starting with '.', but '.*' does not. When I stupidly typed 'rm -r -f .*', it did more or les what I originally thought it would: deleted all the files in all the directories (but only on the /tmp device, because .. linked to the itself in /tmp, so it didn't escape from that volume); leaving all the directories, but empty, except for the files .foo0 and .bar0. So files and inferior directories with names starting with '.' would have escaped, but nothing else. Noel

7 years, 9 months

Re: [TUHS] There is turmoil in Linux-land - When did rm first avoid going upwards?

by jnc＠mercury.lcs.mit.edu

> From: "Ron Natalie" > Actually, it's the shell that calls glob. Yes, in the initial expansion of the command line, but V6 'rm' also uses 'glob' internally; if the '-r' flag is given, and the current name in the command argument list is a directory, viz.: if ((buf->mode & 060000) == 040000) { if (rflg) { ... execl("/etc/glob", "glob", "rm", "-r", fflg? "-f": "*", fflg? "*": p, 0); printf("%s: no glob\n", arg); exit(); } (where 'p' is 0 - no idea why the writer didn't just say '"*": 0, 0'). So "rm -f foo*", where the current directory contains file 'foo0 foo1 foo2' and directoty 'foobar', and directory 'foobar' contains 'bar0 bar1 bar2', the first instance of 'glob' (run by the shell) expands the 'foo0 foo1 foo2 foobar' and the second instance (run by 'rm') expands the 'bar0 bar1 bar2'. > Glob then invokes the command (in this case rm). I don't totally grok 'glob', but it is prepared to exec() either the command name, /bin/{command} or /usr/bin/{command}; but if that file is not executable it tries feeding it to the shell, on the assumption it must be a shell command list: execv(file, arg); if (errno==ENOEXEC) { arg[0] = file; *--arg = "/bin/sh"; execv(*arg, arg); } I guess (too lazy to look) that the execv() must return a different error number if the file doesn't exist at all, so it only tries the shell if the file existed, but wasn't executable. Noel

7 years, 9 months

Runaway rm -r

by Ron Natalie

There was an incident at Pixar that a runaway rm ate most of the Toy Story 2 movie. The only thing that saved them was an employee had their own copy on a machine at home. We never lost the whole disk through one of these, but we did have a guy wipe out /etc/passwd one day. Our password fields had an rfc-822ish user name in the gcos field, so it looked something like: ron::51:50:Ronald Natalie <ron>:/sys1/ron: Well, one of our users decided to grep for a user (alas while root) with the command grep <howard> /etc/passwd

7 years, 9 months

There is turmoil in Linux-land - When did rm first avoid going upwards?

by Josh Good

Hello all. It's off-topic for this list, but there is turmoil in Linux-land. A bug was discovered in systemd, whereby systemd re-implemented "rm" functionality without following POSIX "rm" behaviour. This could kill a system, as explained here: https://github.com/systemd/systemd/issues/5644 The reference POSIX "rm" behaviour is that "rm -rf .*" should NOT delete the current and parent directories, as stated here: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/rm.html#tag_20_11… So, to get on-topic, I have a question for UNIX historians: when was it first defined in the UNIX realm that "rm -r .*" should NOT delete the current and parent directories? Would the command "cd /tmp ; rm -rf .*" be able to kill a V6 or V7 UNIX system? Regards, -- Josh Good

7 years, 9 months

Zilog Z80 Unix

by Erik E. Fair

I have a memory of having seen a Zilog Z-80 (not Z8002 like the Onyx) based Unix, possibly v6, at a vendor show or conference - perhaps the West Coast Computer Faire (WCCF) in the late 1970s or early 1980s. I recall asking the people in the booth how they managed without an MMU, and don't recall their answer. I do remember thinking that since Unix had "grown up" with MMUs to stomp on obvious pointer mistakes, the software ought to be relatively well-behaved ... you know: not trying to play "core war" with itself? I searched the TUHS archives cursorily with Google to see if this has been previously mentioned, but pretty much all Z80 CPU references have for its use in "smart" I/O devices back in the day. Does anyone else remember this Z80 Unix and who did it? Or maybe that it was a clone of some kind ... ? looking for a little history, Erik Fair

7 years, 9 months

Bourne shell and comments

by Warren Toomey

I was trying to configure C news on 2.9BSD today and I found that its Bourne shell doesn't grok # comments. The Bourne shell in 2.11BSD does. So I thought: when did the Bourne (and other) shells first grok # as indicating a comment? Was this in response to #! being added to the kernel, or was it the other way around? And was the choice of #! arbitrary, or was it borrowed from somewhere else? Datum point: 2.9BSD's kernel can recognise #!, but the sh can't recognise #. Cheers, Warren

7 years, 9 months

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