popen writes to a shell but wont read

[Jeff Shannon]

dave wrote:

> Im trying to use popen3 to read and write to s shell process. The write
> bit seems to complete but the read doesnt return. looks like blocking
> but using '`b' in popen makes no difference either.
>
> "
>     #invoke a root shell
>     whoami=string.strip(os.popen(luser).read())
>     if whoami != 'root':
>         w,r,e =os.popen3(rootshell) #w,r,e order makes no difference
>     try:
>         w.write(passwd)
>     except Exception, ex:
>         raise Exception, ex+"password failure"
>     print r.read() #waits here forever
> "

Just a wild guess, but you might try flushing after you write...

        w.write(passwd)
        w.flush()

If your file object is buffered (and I *think* that popen-returned objects are), then
the shell process will not actually receive the data until the buffer is flushed.

You may also wish to try to set up a timeout on your read() ...

Jeff Shannon
Technician/Programmer
Credit International