[cs631apue] Logging and Clarification on Instructions

[Jan Schaumann]

tparisi <tparisi at stevens.edu> wrote:

> 1. What is the difference between the directory that is passed to ./sws  
> and ~ in the HTTP message from the client? Is the ~ supposed to be  
> translated into the path that was given to ./sws?

The directory given to sws(1) on the command-line is that from which all
requests are resolved.  That is:

$ sws /usr/share/htdocs

would mean that requests would be resolved relative to that directory.
Requests for /~<username> however, are always resolved to a per-user
specific directory:

HTTP request        absolute pathname
-----------------------------------------------------------------------
/                   /usr/share/htdocs/index.html (or directory listing)
/foo.html           /usr/share/htdocs/foo.html
/dir/bar.html       /usr/share/htdocs/dir/bar.html
/~jschauma/         /home/jschauma/sws/index.html (or directory listing)
/~jschauma/foo.html /home/jschauma/sws/foo.html 
/dir/../foo.html    /usr/share/htdocs/foo.html
/../../../foo.html  /usr/share/htdocs/foo.html
/~bob/../foo.html   /usr/share/htdocs/foo.html

The last two are important: you must not allow a user to request files
outside of the directory given to sws(1) at startup.

> 2. Does the CGI directory have to be lower in the filesystem hierarchy  
> than the directory given to ./sws? For example, can the CGI directory be  
> /home/tparisi while the root directory for ./sws is /home/tparisi/sws.   

The given root directory and the directory given to '-c' can be entirely
different and the cgi directory need not be a subdirectory of the root
directory (though it _can_ be):

$ pwd
/home/jschauma
$ sws -c ./cgi-bin ./sws

HTTP request       absolute pathname
------------------------------------------------------------------------
/                   /home/jschauma/sws/index.html (or directory listing)
/cgi-bin/foo        /home/jschauma/cgi-bin/foo

$ pwd
/home/jschauma
$ sws -c ./sws/cgi-bin ./sws

HTTP request       absolute pathname
------------------------------------------------------------------------
/                   /home/jschauma/sws/index.html (or directory listing)
/cgi-bin/foo        /home/jschauma/sws/cgi-bin/foo

> 3. What debug is to be printed when the -d flag is specified? Is the  
> error messages when something goes wrong enough or is there something  
> else to print?

Any information you consider useful when debugging the server.

> 4. As far as logging goes, is there a system call that does this? I  
> found out there is an "openlog" system call however that does not allow  
> the user to specify the file to use.

We'll discuss this in a few minutes. :-)

-Jan