On Thu, Mar 30, 2000 at 10:03:14AM -0500, Daniel Martin wrote: > Well, if I do a > $process | file -b - | magic2mime > > where "$process" is anything that produces a large amount of output > slowly, then the process is killed by a SIGPIPE in short order. > > If, however, I do: > $process | (file -b -; cat >/dev/null) | magic2mime > then it seems that the process runs happily (that is, no signals) to > completion. > > However, this may not be what you really would want. (Since waiting > for process to finish could cause the webserver to time out) What > your problem may be is that somehow the cat process is not receiving > the SIGPIPE signal; I would then try to see about rewriting the dwww > script so that it does. (I'm not sure how to do this, since the bash > manpage seems to imply that one can't change which signals are ignored > by the shell).
I just read this one message so I don't know what the original problem is. However, I think you are misdiagnosing or misexplaining this. The SIGPIPE goes to and only to $process. The reason is that file closes its stdin as soon as it has ready a few bytes, with the result that $process then has nowhere to write. cat cannot get a SIGPIPE because it is writing to /dev/null, which rarely stops accepting bits. As far as the web server timing out, without knowing the full context I believe that whatever script is calling this pipeline can just kill it after reading what it needs from magic2mime. Course, this might be a problem if any of the programs in the pipeline handle their buffers in unfortunate ways, causing the output from magic2mime to wait for the completion of $process.... My apologies if you understood this and I just misread your message. Andrew
