Gregory Machin am Freitag, 15. Dezember 2006 14:05:
> On 12/14/06, D. Bolliger <[EMAIL PROTECTED]> wrote:
> > Gregory Machin am Donnerstag, 14. Dezember 2006 13:24:
[reordered]
> > > #!/usr/bin/perl
> > >
> > > # if your prgram has the string "grep" in the name or in the path
> > > # this program won't work.
> > >
> > > use strict;
> > > use warnings;
> > >
> > > my $line;
> > > my $input;
> > >
> > > $input=$ARGV[0]; #$input="httpd";
> > > chomp $input;
> > > open PROS, "ps -ef|grep $input |";
> > >
> > > while ($line = <PROS>){
> > > unless ($line =~ m/grep/){
> > > print "$input is running\n";
> > > exit;
> > > }
> > > }
> > >
> > > print "$input isn't running\n";
> > > exec "/etc/init.d/$input restart &";
> > > the script will not work
> >
> > "Not work?" :-)
> >
> > > if I use $ARGV[0] but works 100% if I hard
> > > code the $input variable;
> > > what have i missed ?
> >
> > You can give anything as cmd line argument, and the script will tell you
> > that it is not running, because of
> >
> > a) open PROS, "ps -ef|grep $input |";
> > combined with
> > b) unless ($line =~ m/grep/){...}
> >
> > This script is running as root... that makes it even more important to
> > check user provided data, what exactly is executed in the shell, and what
> > binaries are called.
> >
> > - use absolute paths for binaries (ps and grep in this case)
> > - make sure that $input only contains ascii characters
> > for example, in this case, only a to z:
> >
> > my ($input) = $ARGV[0]=~/([a-z]{,16})/; # untested
> > die unless $input;
> >
> > btw: /etc/init.d/grep start ???
> >
> > This is a hint to also check if $input corresponds to a binary
> > in /etc/init.d at the beginning of the script :-)
> >
> > This would solve the grep-not-allowed/script-uses-grep-and-does-not-work
> > problem :-)
> >
> > What about also using /etc/init.d/some_daemon status and check if this
> > information is in sync with the ps output (it isn't always, and the
> > restart could therefore fail - what you don't test)
> Hi thanks for looking at the script..
>
> Just to clarify, the scipt runs perfectly if $input it hardcoded eg
> $input="httpd".
> thus if the process is running then it exits, if the process is not
> running then it exicutes
> exec "/etc/init.d/$input restart &";
Hm, possibly I overlooked something, misinterpreted my tests (with modified
code), and guessed wrong. At the moment I have no time to look further at it,
so just a small tip:
> But if I use $input=$ARGV[0] to give the process name from the command
> line, it runs as if the process is running if if I have stoped/killed
> it..
>
> the only reason for this is that there is a hidden character, but
> where is it comming from ?
What hidden character is it? I think it's not a line end character \r, \n,
^M... (you chomp())
What results when you print out $input and the cmdline to be executed like
this, to see the string between '<' and '>':
warn "<$whatever_to_print>"; ?
Dani
P.S.: Please post inline :-)
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