CGI scripts are run by the HTTPD, and therefore by the UID of the HTTPD process, which is (by CONVENTION) usually a special user "nobody".

There are two basic ways to run a script under your own userid:

(1) The direct approach: use a setuid PROGRAM.

(2) The double-server approach: have your CGI script communicate with a second process (e.g. a daemon) running under your userid, which is responsible for the actual file management.

The direct approach is usually faster, but the client-server architecture may help with other problems, such as maintaining integrity of a database.

When running a compiled CGI program (e.g. C, C++), you can make it setuid by simply setting the setuid bit:

e.g. "chmod 4755 myprog.cgi"

For security reasons, this is not possible with scripting languages (eg Perl, Tcl, shell). A workaround is to run them from a setuid program, such as cgiwrap.

In most cases where you'd want to use the client-server approach, the server is a finished product (such as an SQL server) with its own CGI interface.

A lightweight alternative to this is Don Libes' "expect" package.

CGI scripts are run by the HTTPD, and therefore by the UID of the HTTPD process, which is (by convention) usually a special user "nobody".

There are two basic ways to run a script under your own userid:

(1) The direct approach: use a setuid program.

(2) The double-server approach: have your CGI script communicate with a second process (e.g. a daemon) running under your userid, which is responsible for the actual file management.

The direct approach is usually faster, but the client-server architecture may help with other problems, such as maintaining integrity of a database.

When running a compiled CGI program (e.g. C, C++), you can make it setuid by simply setting the setuid bit:

e.g. "chmod 4755 myprog.cgi"

For security reasons, this is not possible with scripting languages (eg Perl, Tcl, shell). A workaround is to run them from a setuid program, such as cgiwrap.

In most cases where you'd want to use the client-server approach, the server is a finished product (such as an SQL server) with its own CGI interface.

A lightweight alternative to this is Don Libes' "expect" package.