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npf_extmod.c revision 1.3.4.2 
      1 /*	$NetBSD: npf_extmod.c,v 1.3.4.2 2012/11/20 03:03:03 tls Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2012 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Mindaugas Rasiukevicius.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * npfctl(8) extension loading interface.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 __RCSID("$NetBSD: npf_extmod.c,v 1.3.4.2 2012/11/20 03:03:03 tls Exp $");
     38 
     39 #include <stdlib.h>
     40 #include <inttypes.h>
     41 #include <string.h>
     42 #include <err.h>
     43 #include <dlfcn.h>
     44 
     45 #include "npfctl.h"
     46 
     47 struct npf_extmod {
     48 	char *			name;
     49 	npfext_initfunc_t	init;
     50 	npfext_consfunc_t	cons;
     51 	npfext_paramfunc_t	param;
     52 	struct npf_extmod *	next;
     53 };
     54 
     55 static npf_extmod_t *		npf_extmod_list;
     56 
     57 static void *
     58 npf_extmod_sym(void *handle, const char *name, const char *func)
     59 {
     60 	char buf[64];
     61 	void *sym;
     62 
     63 	snprintf(buf, sizeof(buf), "npfext_%s_%s", name, func);
     64 	sym = dlsym(handle, buf);
     65 	if (sym == NULL) {
     66 		errx(EXIT_FAILURE, "dlsym: %s", dlerror());
     67 	}
     68 	return sym;
     69 }
     70 
     71 static npf_extmod_t *
     72 npf_extmod_load(const char *name)
     73 {
     74 	npf_extmod_t *ext;
     75 	void *handle;
     76 	char extlib[PATH_MAX];
     77 
     78 	snprintf(extlib, sizeof(extlib), "/usr/lib/npf/ext_%s.so", name);
     79 	handle = dlopen(extlib, RTLD_LAZY | RTLD_LOCAL);
     80 	if (handle == NULL) {
     81 		errx(EXIT_FAILURE, "dlopen: %s", dlerror());
     82 	}
     83 
     84 	ext = ecalloc(1, sizeof(npf_extmod_t));
     85 	ext->name = estrdup(name);
     86 	ext->init = npf_extmod_sym(handle, name, "init");
     87 	ext->cons = npf_extmod_sym(handle, name, "construct");
     88 	ext->param = npf_extmod_sym(handle, name, "param");
     89 
     90 	/* Initialise the module. */
     91 	if (ext->init() != 0) {
     92 		free(ext);
     93 		return NULL;
     94 	}
     95 
     96 	ext->next = npf_extmod_list;
     97 	npf_extmod_list = ext;
     98 	return ext;
     99 }
    100 
    101 npf_extmod_t *
    102 npf_extmod_get(const char *name, nl_ext_t **extcall)
    103 {
    104 	npf_extmod_t *extmod = npf_extmod_list;
    105 
    106 	while (extmod) {
    107 		if ((strcmp(extmod->name, name) == 0) &&
    108 		    (*extcall = extmod->cons(name)) != NULL) {
    109 			return extmod;
    110 		}
    111 		extmod = extmod->next;
    112 	}
    113 
    114 	extmod = npf_extmod_load(name);
    115 	if (extmod && (*extcall = extmod->cons(name)) != NULL) {
    116 		return extmod;
    117 	}
    118 
    119 	return NULL;
    120 }
    121 
    122 int
    123 npf_extmod_param(npf_extmod_t *extmod, nl_ext_t *ext,
    124     const char *param, const char *val)
    125 {
    126 	return extmod->param(ext, param, val);
    127 }
    128