execute problems

muzzol muzzol at gmail.com
Tue Sep 19 14:07:10 UTC 2006

> man dhcp-eval
> ...
>      execute(command-path, data-expr1 ... data-exprN);
>        External command execution is made possible  through  exe-
>        cute();  expressions.   These  expressions take a variable
>        number of arguments, where the first is the  command  name
>        (full path or only the name of the executable) and is fol-
>        lowed by zero or more are  data-expressions  whose  values
>        will   be  evaluated  and  passed  as  external  arguments
>        (assumed  to  be  text  strings  suitable  for  use  as  a
>        command-line  argument).   It  returns  the numeric return
>        code of the external command, or one of the following spe-
>        cial values:
>        o 125: Invalid arguments.
>        o 126: fork() failure
>        o 127: execvp() failure
>        o -SIGNAL: Should the child exit due to a  signal,  rather
>          than  exiting  normally  with an exit status, the signal
>          number multiplied by negative 1 will be returned.
>        Execute is synchronous, and the program will  block  until
>        the  external  command being run has finished. Please note
>        that lengthy program execution (for  example,  in  an  "on
>        commit"  in  dhcpd.conf) may result in bad performance and
>        timeouts.  Only external applications with very short exe-
>        cution times are suitable for use.
>        Passing user-supplied  data  to  an  external  application
>        might  be  dangerous.   Make sure the external application
>        checks input buffers for  validity.   Non-printable  ASCII
>        characters  will  be  converted  into  dhcpd.conf language
>        octal escapes ("777"), make  sure  your  external  command
>        handles them as such.
>        It is possible to use the execute expression in  any  con-
>        text, not only on events. If you put it in a regular scope
>        in the configuration file you will  execute  that  command
>        every time a scope is evaluated.
thanks for info, my version of dhcp-eval dont show this part, si i'll
recompile whith lastest build.

> What particular type of information are you interested in?

im insterested in giving acces to certain users depending of their
configuration. for example, if they are windows users (this is covered
in another thread), if they have some ports opened, if they have some
services activated. so it could be nice to create a script against
every client trying to get an ip and evaluate it.


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     O O
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