apache module

gistfile1.h

#include <stdio.h>
#include <string.h>

#include "apr.h"
#include "apr_file_io.h"
#include "apr_strings.h"
#include "apr_lib.h"

#define APR_WANT_STRFUNC
#include "apr_want.h"

#include "httpd.h"
#include "http_core.h"
#include "http_config.h"
#include "http_request.h"
#include "http_log.h"

module AP_MODULE_DECLARE_DATA mod_font;

typedef struct {
	int enabled;
} modfontconfig;

/*
 * Create a configuration specific to this module for a server or directory
 * location, and fill it with the default settings.
 *
 * The API says that in the absence of a merge function, the record for the
 * closest ancestor is used exclusively.  That's what we want, so we don't
 * bother to have such a function.
 */

static void *mkconfig(apr_pool_t *p)
{
	modfontconfig *cfg = apr_pcalloc(p, sizeof(modfontconfig));

	cfg->enabled = 0;
	return cfg;
}

/*
 * Respond to a callback to create configuration record for a server or
 * vhost environment.
 */
static void *create_mconfig_for_server(apr_pool_t *p, server_rec *s)
{
	return mkconfig(p);
}

/*
 * Respond to a callback to create a config record for a specific directory.
 */
static void *create_mconfig_for_directory(apr_pool_t *p, char *dir)
{
	return mkconfig(p);
}

static const char *set_modfont(cmd_parms *cmd, void *mconfig, int arg)
{
	modfontconfig *cfg = (modfontconfig *) mconfig;

	cfg->enabled = arg;
	return NULL;
}

/*
 * Define the directives specific to this module.  This structure is referenced
 * later by the 'module' structure.
 */
static const command_rec modfont_cmds[] =
{
	AP_INIT_FLAG("modfont", set_modfont, NULL, OR_OPTIONS,
				 "whether or not to convert TTFs to EOTs for IE requests"),
	{ NULL }
};

static int check_font(request_rec *r)
{
	modfontconfig *cfg;
	char *good, *bad, *postgood, *url;
	apr_finfo_t dirent;
	int filoc, dotloc, urlen, pglen;
	apr_dir_t		   *dir;
	
	cfg = ap_get_module_config(r->per_dir_config, &mod_font);
	if (!cfg->enabled)
	{
		return DECLINED;
	}

	/* We only want to worry about GETs */
	if (r->method_number != M_GET)
	{
		return DECLINED;
	}
	
	/* If browser is not IE, bug out */
	const char *user_agent;
	user_agent = apr_table_get(r->headers_in, "User-Agent");
	if (strstr(user_agent, "MSIE") == 0)
	{
		return DECLINED;
	}

	/* We've already got a file of some kind or another */
/*	if (r->proxyreq || (r->finfo.filetype != 0)) {
		return DECLINED;
	}
*/
	/* This is a sub request - don't mess with it */
/*	if (r->main) {
		return DECLINED;
	}
*/
	filoc = ap_rind(r->filename, '/');
	/*
	 * Don't do anything if the request doesn't contain a slash, or
	 * requests "/"
	 */
	if (filoc == -1 || strcmp(r->uri, "/") == 0)
	{
		return DECLINED;
	}

	/* good = /correct-file */
	good = apr_pstrndup(r->pool, r->filename, filoc);
	/* bad = mispelling */
	bad = apr_pstrdup(r->pool, r->filename + filoc + 1);
	/* postgood = mispelling/more */
	postgood = apr_pstrcat(r->pool, bad, r->path_info, NULL);

	urlen = strlen(r->uri);
	pglen = strlen(postgood);

	/* Check to see if the URL pieces add up */
	if (strcmp(postgood, r->uri + (urlen - pglen)))
	{
		return DECLINED;
	}

	/* url = /correct-url */
	url = apr_pstrndup(r->pool, r->uri, (urlen - pglen));

	/* Now open the directory and do ourselves a check... */
	if (apr_dir_open(&dir, good, r->pool) != APR_SUCCESS)
	{
		/* Oops, not a directory... */
		return DECLINED;
	}

	dotloc = ap_ind(bad, '.');
	if (dotloc == -1)
	{
		dotloc = strlen(bad);
	}

	while (apr_dir_read(&dirent, APR_FINFO_DIRENT, dir) == APR_SUCCESS)
	{
		/*
		 * If we end up with a "fixed" URL which is identical to the
		 * requested one, we must have found a broken symlink or some such.
		 * Do _not_ try to redirect this, it causes a loop!
		 */
		if (strcmp(bad, dirent.name) == 0)
		{
			apr_dir_close(dir);
			return OK;
		}

		int entloc = ap_ind(dirent.name, '.');
		if (entloc == -1)
		{
			entloc = strlen(dirent.name);
		}

		if ((dotloc == entloc) && !strncasecmp(bad, dirent.name, dotloc))
		{
			char *new_url = apr_pstrdup(r->pool, dirent.name);
			
			char *nuri;
			const char *ref;
			
			ref = apr_table_get(r->headers_in, "Referer");

			nuri = ap_escape_uri(r->pool, apr_pstrcat(r->pool, url, new_url, r->path_info, NULL));
			if (r->parsed_uri.query)
				nuri = apr_pstrcat(r->pool, nuri, "?", r->parsed_uri.query, NULL);

			apr_table_setn(r->headers_out, "Location",
						  ap_construct_url(r->pool, nuri, r));

			ap_log_rerror(APLOG_MARK, APLOG_INFO, APR_SUCCESS,
						  r,
						  ref ? "Redirected font: %s to %s from %s"
							  : "Redirected font: %s to %s",
						  r->uri, nuri, ref);

			return HTTP_MOVED_PERMANENTLY;
		}
	}
	apr_dir_close(dir);

	return OK;
}

static void register_hooks(apr_pool_t *p)
{
	ap_hook_fixups(check_font, NULL, NULL, APR_HOOK_LAST);
}

module AP_MODULE_DECLARE_DATA font_module =
{
	STANDARD20_MODULE_STUFF,
	NULL,  /* create per-dir config */
	NULL,						/* merge per-dir config */
	NULL,	/* server config */
	NULL,						/* merge server config */
	modfont_cmds,						/* command apr_table_t */
	register_hooks				/* register hooks */
};