mod_mime_magic: MIME type lookup via file magic numbers
Copyright (c) 1996-1997 Cisco Systems, Inc.

This software was submitted by Cisco Systems to the Apache Group in July 1997. Future revisions and derivatives of this source code must acknowledge Cisco Systems as the original contributor of this module. All other licensing and usage conditions are those of the Apache Group.

Some of this code is derived from the free version of the file command originally posted to comp.sources.unix. Copyright info for that program is included below as required.

- Copyright (c) Ian F. Darwin, 1987. Written by Ian F. Darwin.

This software is not subject to any license of the American Telephone and Telegraph Company or of the Regents of the University of California.

Permission is granted to anyone to use this software for any purpose on any computer system, and to alter it and redistribute it freely, subject to the following restrictions:

1. The author is not responsible for the consequences of use of this software, no matter how awful, even if they arise from flaws in it.
2. The origin of this software must not be misrepresented, either by explicit claim or by omission. Since few users ever read sources, credits must appear in the documentation.
3. Altered versions must be plainly marked as such, and must not be misrepresented as being the original software. Since few users ever read sources, credits must appear in the documentation.
4. This notice may not be removed or altered.

For compliance with Mr Darwin's terms: this has been very significantly modified from the free "file" command.

• all-in-one file for compilation convenience when moving from one version of Apache to the next.
• Memory allocation is done through the Apache API's pool structure.
• All functions have had necessary Apache API request or server structures passed to them where necessary to call other Apache API routines. (i.e., usually for logging, files, or memory allocation in itself or a called function.)
• struct magic has been converted from an array to a single-ended linked list because it only grows one record at a time, it's only accessed sequentially, and the Apache API has no equivalent of realloc().
• Functions have been changed to get their parameters from the server configuration instead of globals. (It should be reentrant now but has not been tested in a threaded environment.)
• Places where it used to print results to stdout now saves them in a list where they're used to set the MIME type in the Apache request record.
• Command-line flags have been removed since they will never be used here.