aims@ssc-vax.UUCP (John Daley) (08/22/85)
We have a question that maybe you can answer. Does anyone out there know
of any utilities that use the information in /etc/group? We keep our file
up to date, but have never noticed any system uses for this file. I have
used fgrep to compare group id numbers and user names, but that is a script
that I developed for simple cross-checking.
Just wondering...Thanx in advance! (Please post responses in net.unix)
--
From the merciless keys of Ray Saddler
Nothing I say here is to be held against the Boeing company,
It's not their fault!
Ray E. Saddler III
Boeing Aerospace Company
CAD Support and Administration
Seattle, Washington
USA
Earth
Somewhere in the universe
lost in space.....dan@mgweed.UUCP (Daniel Gray) (08/26/85)
On our systems, the /etc/group file contains the names of those logins that can change group with `newgrp` command. It changes your group id to that of the group requested, (if you are listed) so that you can access files owned by the other group. Daniel Gray
alan@drivax.UUCP (Alan Fargusson) (08/26/85)
> We have a question that maybe you can answer. Does anyone out there know > of any utilities that use the information in /etc/group? We keep our file > up to date, but have never noticed any system uses for this file. Ls(1), and newgrp(1) uses it. On 5.2.2 ls(1) prints the group by default, but othere flavors of UNIX it is an option. -- Alan Fargusson. { ihnp4, amdahl, mot }!drivax!alan
carl@bdaemon.UUCP (carl) (08/27/85)
> > > We have a question that maybe you can answer. Does anyone out there know > of any utilities that use the information in /etc/group? We keep our file > up to date, but have never noticed any system uses for this file. I have > used fgrep to compare group id numbers and user names, but that is a script > that I developed for simple cross-checking. > > Just wondering...Thanx in advance! (Please post responses in net.unix) The shell builtin 'newgrp' is but one example. Carl Brandauer daemon associates 1760 Sunset Blvd. Boulder, CO 80302 {allegra|amd|attunix|cbosgd|ucbvax}!nbires!bdaemon!carl
broman@noscvax.UUCP (Vincent P. Broman) (08/27/85)
> We have a question that maybe you can answer. Does anyone out there know > of any utilities that use the information in /etc/group? We keep our file > up to date, but have never noticed any system uses for this file. just the obvious one-- it determines your group access permissions. On 4.2BSD at least, this is done by a call to initgroups(3X) in login.c . Vincent Broman MILNET: broman@nosc Analysis Branch, code 632 UUCP: {ihnp4,decvax,akgua,dcdwest,ucbvax}! Naval Ocean Systems Center sdcsvax!noscvax!broman San Diego, CA 92152 MaBellNet: (619) 225-2365
electrohome@watcgl.UUCP (electrohome) (08/28/85)
Please get this discussion out of net.misc now that there are some reasonable responses.
fred@mot.UUCP (Fred Christiansen) (08/29/85)
don't forget grpck(1M) to sanity-check /etc/group cross-matched to /etc/passwd
^
| wasn't this the name of the Czech Pres/P.M. back in '67? :-)
--
<< Generic disclaimer >>
Fred Christiansen ("Canajun, eh?") @ Motorola Microsystems, Tempe, AZ
UUCP: ihnp4!{attunix, btlunix, drivax, sftig, ut-sally!oakhill}!mot!fred
ARPA: oakhill!mot!fred@ut-sally.ARPA AT&T: 602-438-3472cmv@cbnap.UUCP (Craig Votava) (08/30/85)
In article <217@drivax.UUCP> alan@drivax.UUCP (Alan Fargusson) writes: > We have a question that maybe you can answer. Does anyone out there know > of any utilities that use the information in /etc/group? We keep our file > up to date, but have never noticed any system uses for this file. Doesn't old mail(1) (not mailx) allow you to mail <group> which will mail to the whole group? Craig Votava ...ihnp4!cbnap!cmv cb/eadas/nap - datakit
matt@saber.UUCP (Matt Perez) (08/30/85)
> > We have a question that maybe you can answer. Does anyone out there know > of any utilities that use the information in /etc/group? We keep our file > up to date, but have never noticed any system uses for this file. I have > used fgrep to compare group id numbers and user names, but that is a script > that I developed for simple cross-checking. > > Just wondering...Thanx in advance! (Please post responses in net.unix) > "ls -g" to display the file owner's group name. matt perez saber technology/2381 bering drive/san jose ca 95131 408 945-9600 saber!matt
chuqui@nsc.UUCP (Chuq Von Rospach) (08/30/85)
[followups will be rerouted to only net.unix as the best place to continue this discussion] In article <1762@saber.UUCP> matt@saber.UUCP (Matt Perez) writes: >> >> We have a question that maybe you can answer. Does anyone out there know >> of any utilities that use the information in /etc/group? We keep our file >> up to date, but have never noticed any system uses for this file. > >"ls -g" to display the file owner's group name. I had expected someone to mention this by now, but since I haven't seen it, 4.2BSD Un*x added the capability to be in multiple groups at the same time, based on the data in the /etc/group file. This means, for example, that you could have your default group be "staff" in /etc/passwd, but also be in grous like "kernel" or "netnews" or whatever at the same time. This allows you to use the group permissions on files and directories in a pretty flexible way (finally) for allowing access to various development areas on a single machine. This means that (in essence) any utility can use or misused the information in /etc/group depending on how you want to set things up... chuq access to -- Chuq Von Rospach nsc!chuqui@decwrl.ARPA {decwrl,hplabs,ihnp4}!nsc!chuqui Son, you're mixing ponderables again
nz@wucs.UUCP (Neal Ziring) (08/30/85)
In article <147@ssc-vax.UUCP>, aims@ssc-vax.UUCP (John Daley) writes: > > We have a question that maybe you can answer. Does anyone out there know > of any utilities that use the information in /etc/group? We keep our file > up to date, but have never noticed any system uses for this file. > > Just wondering...Thanx in advance! (Please post responses in net.unix) > > From the merciless keys of Ray Saddler The /etc/group file is the system master list of group accesses. For user programs, it is used for translating gid values into mnemonic names (gid 100 = staff, for instance). There are library routines that open, read, and parse the file, so you will never see a program actually open the file "/etc/group". The information about these library routines can get read in manual entry getgrent(3). The more important use of /etc/group (actually groups in a more general sense) is in the kernel. You may have noticed by now that all files have four bits of permission related to user group. When you login, or su, the program reads the /etc/group file to determine what groups you are a member of, and performs the system call setgroups(2) to tell the kernel that you belong to a certain list of groups (an array of gids) and no others. For further information, see setgroups(2), access(2), getgrent(3), group(5), and the source for libc. -- ======== ...nz (ECL - we're here to provide superior computing) Washington University Engineering Computer Laboratory "Now we'll see some proper action..." old style: ... ihnp4!wucs!nz new style: nz@wucs.UUCP
jeq@laidbak.UUCP (Jonathan E. Quist) (09/01/85)
>> We have a question that maybe you can answer. Does anyone out there know >> of any utilities that use the information in /etc/group? We keep our file It comes in handy for granting access to group-maintained files without granting global access. E.G. `cat /etc/group` ... wheel:*:0:root,phred cheese:*:6:mrbig,msbig,buffy,johnboy,zaphod users::123:winkin,blinkin,nod,phred abusers::456:hardrock,coco,joe,phred ... `ls -lg /usr/local/*userfile /etc/passwd /usr/games/rogue` -rw-rw-r-- 1 blinkin users 94066 Jul 1 10:34 /usr/local/userfile -rw-rw---- 1 coco abusers 13 Jul 4 1776 /usr/local/abuserfile -rw-r--r-- 1 root wheel 11307 Aug 29 22:06 /etc/passwd -rws--x--- 1 daemon cheese 117760 Apr 28 15:38 /usr/games/rogue ^ ^ owner group Blinkin owns ``userfile''; winkin, blinkin, and nod (the ``users'' can all read from and write to this file. Coco owns ``abuserfile''; hardrock, coco, and joe (``abusers'') can all read and write this file. The `regular' users can _not_ read abuserfile. Everyone can read /etc/passwd. Phred, being something of a minor deity, can read and write both files, as well as /etc/passwd. (Phred had better be a trusted user.) Only members of group cheese (XYZ company's presidant and his family) are allowed to play ``rogue''. Everyone agree? Light your oxy-acetylene torches if I've got any of the details wrong. Jonathan E. Quist Lachman Associates, Inc. ihnp4!laidbak!jeq ``I deny this is a disclaimer.''
marinkov@gumby.UUCP (09/10/85)
> On our systems, the /etc/group file contains the names of those logins > that can change group with `newgrp` command. It changes your group id > to that of the group requested, (if you are listed) so that you can > access files owned by the other group. > > Daniel Gray *** REPLACE THIS LINE WITH YOUR MESSAGE ***