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      1 /*-
      2  * Copyright (c) 2012 The NetBSD Foundation, Inc.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to The NetBSD Foundation
      6  * by Mindaugas Rasiukevicius.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     27  * POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 /*
     31  * npfctl(8) extension loading interface.
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 __RCSID("$NetBSD: npf_extmod.c,v 1.5 2018/09/29 14:41:36 rmind Exp $");
     36 
     37 #include <stdlib.h>
     38 #include <inttypes.h>
     39 #include <string.h>
     40 #include <err.h>
     41 #include <dlfcn.h>
     42 
     43 #include "npfctl.h"
     44 
     45 struct npf_extmod {
     46 	char *			name;
     47 	npfext_initfunc_t	init;
     48 	npfext_consfunc_t	cons;
     49 	npfext_paramfunc_t	param;
     50 	struct npf_extmod *	next;
     51 };
     52 
     53 static npf_extmod_t *		npf_extmod_list;
     54 
     55 static void *
     56 npf_extmod_sym(void *handle, const char *name, const char *func)
     57 {
     58 	char buf[64];
     59 	void *sym;
     60 
     61 	snprintf(buf, sizeof(buf), "npfext_%s_%s", name, func);
     62 	sym = dlsym(handle, buf);
     63 	if (sym == NULL) {
     64 		errx(EXIT_FAILURE, "dlsym: %s", dlerror());
     65 	}
     66 	return sym;
     67 }
     68 
     69 static npf_extmod_t *
     70 npf_extmod_load(const char *name)
     71 {
     72 	npf_extmod_t *ext;
     73 	void *handle;
     74 	char extlib[PATH_MAX];
     75 
     76 	snprintf(extlib, sizeof(extlib), "/lib/npf/ext_%s.so", name);
     77 	handle = dlopen(extlib, RTLD_LAZY | RTLD_LOCAL);
     78 	if (handle == NULL) {
     79 		errx(EXIT_FAILURE, "dlopen: %s", dlerror());
     80 	}
     81 
     82 	ext = ecalloc(1, sizeof(npf_extmod_t));
     83 	ext->name = estrdup(name);
     84 	ext->init = npf_extmod_sym(handle, name, "init");
     85 	ext->cons = npf_extmod_sym(handle, name, "construct");
     86 	ext->param = npf_extmod_sym(handle, name, "param");
     87 
     88 	/* Initialise the module. */
     89 	if (ext->init() != 0) {
     90 		free(ext);
     91 		return NULL;
     92 	}
     93 
     94 	ext->next = npf_extmod_list;
     95 	npf_extmod_list = ext;
     96 	return ext;
     97 }
     98 
     99 npf_extmod_t *
    100 npf_extmod_get(const char *name, nl_ext_t **extcall)
    101 {
    102 	npf_extmod_t *extmod = npf_extmod_list;
    103 
    104 	while (extmod) {
    105 		if ((strcmp(extmod->name, name) == 0) &&
    106 		    (*extcall = extmod->cons(name)) != NULL) {
    107 			return extmod;
    108 		}
    109 		extmod = extmod->next;
    110 	}
    111 
    112 	extmod = npf_extmod_load(name);
    113 	if (extmod && (*extcall = extmod->cons(name)) != NULL) {
    114 		return extmod;
    115 	}
    116 
    117 	return NULL;
    118 }
    119 
    120 int
    121 npf_extmod_param(npf_extmod_t *extmod, nl_ext_t *ext,
    122     const char *param, const char *val)
    123 {
    124 	return extmod->param(ext, param, val);
    125 }
    126