diff options
Diffstat (limited to 'newlib/libc/sys/linux/net/hesiod.c')
| -rw-r--r-- | newlib/libc/sys/linux/net/hesiod.c | 600 |
1 files changed, 600 insertions, 0 deletions
diff --git a/newlib/libc/sys/linux/net/hesiod.c b/newlib/libc/sys/linux/net/hesiod.c new file mode 100644 index 000000000..909c09440 --- /dev/null +++ b/newlib/libc/sys/linux/net/hesiod.c @@ -0,0 +1,600 @@ +/* $NetBSD: hesiod.c,v 1.9 1999/02/11 06:16:38 simonb Exp $ */ + +/* Copyright (c) 1996 by Internet Software Consortium. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS + * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE + * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL + * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR + * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS + * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS + * SOFTWARE. + */ + +/* Copyright 1996 by the Massachusetts Institute of Technology. + * + * Permission to use, copy, modify, and distribute this + * software and its documentation for any purpose and without + * fee is hereby granted, provided that the above copyright + * notice appear in all copies and that both that copyright + * notice and this permission notice appear in supporting + * documentation, and that the name of M.I.T. not be used in + * advertising or publicity pertaining to distribution of the + * software without specific, written prior permission. + * M.I.T. makes no representations about the suitability of + * this software for any purpose. It is provided "as is" + * without express or implied warranty. + */ + +/* This file is part of the hesiod library. It implements the core + * portion of the hesiod resolver. + * + * This file is loosely based on an interim version of hesiod.c from + * the BIND IRS library, which was in turn based on an earlier version + * of this file. Extensive changes have been made on each step of the + * path. + * + * This implementation is not truly thread-safe at the moment because + * it uses res_send() and accesses _res. + */ + +#include <sys/cdefs.h> + +#if 0 +static char *orig_rcsid = "$NetBSD: hesiod.c,v 1.9 1999/02/11 06:16:38 simonb Exp $"; +#endif +#include <sys/cdefs.h> +#include <sys/types.h> +#include <machine/endian.h> + +#include <sys/types.h> +#include <sys/param.h> +#include <netinet/in.h> +#include <arpa/nameser.h> + +#include <ctype.h> +#include <errno.h> +#include <hesiod.h> +#include <resolv.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +struct hesiod_p { + char *lhs; /* normally ".ns" */ + char *rhs; /* AKA the default hesiod domain */ + int classes[2]; /* The class search order. */ +}; + +#define MAX_HESRESP 1024 + +static int read_config_file(struct hesiod_p *, const char *); +static char **get_txt_records(int, const char *); +static int init_context(void); +static void translate_errors(void); + + +/* + * hesiod_init -- + * initialize a hesiod_p. + */ +int +hesiod_init(context) + void **context; +{ + struct hesiod_p *ctx; + const char *p, *configname; + + ctx = malloc(sizeof(struct hesiod_p)); + if (ctx) { + *context = ctx; + if (!issetugid()) + configname = getenv("HESIOD_CONFIG"); + else + configname = NULL; + if (!configname) + configname = _PATH_HESIOD_CONF; + if (read_config_file(ctx, configname) >= 0) { + /* + * The default rhs can be overridden by an + * environment variable. + */ + if (!issetugid()) + p = getenv("HES_DOMAIN"); + else + p = NULL; + if (p) { + if (ctx->rhs) + free(ctx->rhs); + ctx->rhs = malloc(strlen(p) + 2); + if (ctx->rhs) { + *ctx->rhs = '.'; + strcpy(ctx->rhs + 1, + (*p == '.') ? p + 1 : p); + return 0; + } else + errno = ENOMEM; + } else + return 0; + } + } else + errno = ENOMEM; + + if (ctx->lhs) + free(ctx->lhs); + if (ctx->rhs) + free(ctx->rhs); + if (ctx) + free(ctx); + return -1; +} + +/* + * hesiod_end -- + * Deallocates the hesiod_p. + */ +void +hesiod_end(context) + void *context; +{ + struct hesiod_p *ctx = (struct hesiod_p *) context; + + free(ctx->rhs); + if (ctx->lhs) + free(ctx->lhs); + free(ctx); +} + +/* + * hesiod_to_bind -- + * takes a hesiod (name, type) and returns a DNS + * name which is to be resolved. + */ +char * +hesiod_to_bind(void *context, const char *name, const char *type) +{ + struct hesiod_p *ctx = (struct hesiod_p *) context; + char bindname[MAXDNAME], *p, *ret, **rhs_list = NULL; + const char *rhs; + int len; + size_t bindnamelen; + + if (strlcpy(bindname, name, sizeof(bindname)) >= sizeof(bindname)) { + errno = EMSGSIZE; + return NULL; + } + + /* + * Find the right right hand side to use, possibly + * truncating bindname. + */ + p = strchr(bindname, '@'); + if (p) { + *p++ = 0; + if (strchr(p, '.')) + rhs = name + (p - bindname); + else { + rhs_list = hesiod_resolve(context, p, "rhs-extension"); + if (rhs_list) + rhs = *rhs_list; + else { + errno = ENOENT; + return NULL; + } + } + } else + rhs = ctx->rhs; + + /* See if we have enough room. */ + len = strlen(bindname) + 1 + strlen(type); + if (ctx->lhs) + len += strlen(ctx->lhs) + ((ctx->lhs[0] != '.') ? 1 : 0); + len += strlen(rhs) + ((rhs[0] != '.') ? 1 : 0); + if (len > sizeof(bindname) - 1) { + if (rhs_list) + hesiod_free_list(context, rhs_list); + errno = EMSGSIZE; + return NULL; + } + /* Put together the rest of the domain. */ + strcat(bindname, "."); + strcat(bindname, type); + /* Only append lhs if it isn't empty. */ + if (ctx->lhs && ctx->lhs[0] != '\0' ) { + if (ctx->lhs[0] != '.') + strcat(bindname, "."); + strcat(bindname, ctx->lhs); + } + if (rhs[0] != '.') + strcat(bindname, "."); + strcat(bindname, rhs); + + /* rhs_list is no longer needed, since we're done with rhs. */ + if (rhs_list) + hesiod_free_list(context, rhs_list); + + /* Make a copy of the result and return it to the caller. */ + bindnamelen = strlen (bindname) + 1; + ret = malloc (bindnamelen); + if (!ret) + errno = ENOMEM; + else + memcpy (ret, bindname, bindnamelen); + return ret; +} + +/* + * hesiod_resolve -- + * Given a hesiod name and type, return an array of strings returned + * by the resolver. + */ +char ** +hesiod_resolve(context, name, type) + void *context; + const char *name; + const char *type; +{ + struct hesiod_p *ctx = (struct hesiod_p *) context; + char *bindname, **retvec; + + bindname = hesiod_to_bind(context, name, type); + if (!bindname) + return NULL; + + retvec = get_txt_records(ctx->classes[0], bindname); + if (retvec == NULL && errno == ENOENT && ctx->classes[1]) + retvec = get_txt_records(ctx->classes[1], bindname); + + free(bindname); + return retvec; +} + +/*ARGSUSED*/ +void +hesiod_free_list(context, list) + void *context; + char **list; +{ + char **p; + + if (list == NULL) + return; + for (p = list; *p; p++) + free(*p); + free(list); +} + + +/* read_config_file -- + * Parse the /etc/hesiod.conf file. Returns 0 on success, + * -1 on failure. On failure, it might leave values in ctx->lhs + * or ctx->rhs which need to be freed by the caller. + */ +static int +read_config_file(ctx, filename) + struct hesiod_p *ctx; + const char *filename; +{ + char *key, *data, *p, **which; + char buf[MAXDNAME + 7]; + int n; + FILE *fp; + + /* Set default query classes. */ + ctx->classes[0] = C_IN; + ctx->classes[1] = C_HS; + + /* Try to open the configuration file. */ + fp = fopen(filename, "r"); + if (!fp) { + size_t len; + /* Use compiled in default domain names. */ + len = strlen (DEF_LHS) + 1; + ctx->lhs = malloc (len); + if (ctx->lhs) { + memcpy (ctx->lhs, DEF_LHS, len); + len = strlen (DEF_RHS) + 1; + ctx->rhs = malloc (len); + if (ctx->rhs) + memcpy (ctx->rhs, DEF_RHS, len); + } + if (ctx->lhs && ctx->rhs) + return 0; + else { + errno = ENOMEM; + return -1; + } + } + ctx->lhs = NULL; + ctx->rhs = NULL; + while (fgets(buf, sizeof(buf), fp) != NULL) { + p = buf; + if (*p == '#' || *p == '\n' || *p == '\r') + continue; + while (*p == ' ' || *p == '\t') + p++; + key = p; + while (*p != ' ' && *p != '\t' && *p != '=') + p++; + *p++ = 0; + + while (isspace(*p) || *p == '=') + p++; + data = p; + while (!isspace(*p)) + p++; + *p = 0; + + if (strcasecmp(key, "lhs") == 0 || + strcasecmp(key, "rhs") == 0) { + size_t len; + which = (strcasecmp(key, "lhs") == 0) + ? &ctx->lhs : &ctx->rhs; + len = strlen (data) + 1; + *which = malloc (len); + if (!*which) { + errno = ENOMEM; + return -1; + } + else + memcpy (*which, data, len); + } else { + if (strcasecmp(key, "classes") == 0) { + n = 0; + while (*data && n < 2) { + p = data; + while (*p && *p != ',') + p++; + if (*p) + *p++ = 0; + if (strcasecmp(data, "IN") == 0) + ctx->classes[n++] = C_IN; + else + if (strcasecmp(data, "HS") == 0) + ctx->classes[n++] = + C_HS; + data = p; + } + while (n < 2) + ctx->classes[n++] = 0; + } + } + } + fclose(fp); + + if (!ctx->rhs || ctx->classes[0] == 0 || + ctx->classes[0] == ctx->classes[1]) { + errno = ENOEXEC; + return -1; + } + return 0; +} + +/* + * get_txt_records -- + * Given a DNS class and a DNS name, do a lookup for TXT records, and + * return a list of them. + */ +static char ** +get_txt_records(qclass, name) + int qclass; + const char *name; +{ + HEADER *hp; + unsigned char qbuf[PACKETSZ], abuf[MAX_HESRESP], *p, *eom, *eor; + char *dst, **list; + int ancount, qdcount, i, j, n, skip, type, class, len; + + /* Make sure the resolver is initialized. */ + if ((_res.options & RES_INIT) == 0 && res_init() == -1) + return NULL; + + /* Construct the query. */ + n = res_mkquery(QUERY, name, qclass, T_TXT, NULL, 0, + NULL, qbuf, PACKETSZ); + if (n < 0) + return NULL; + + /* Send the query. */ + n = res_send(qbuf, n, abuf, MAX_HESRESP); + if (n < 0) { + errno = ECONNREFUSED; + return NULL; + } + /* Parse the header of the result. */ + hp = (HEADER *) (void *) abuf; + ancount = ntohs(hp->ancount); + qdcount = ntohs(hp->qdcount); + p = abuf + sizeof(HEADER); + eom = abuf + n; + + /* + * Skip questions, trying to get to the answer section + * which follows. + */ + for (i = 0; i < qdcount; i++) { + skip = dn_skipname(p, eom); + if (skip < 0 || p + skip + QFIXEDSZ > eom) { + errno = EMSGSIZE; + return NULL; + } + p += skip + QFIXEDSZ; + } + + /* Allocate space for the text record answers. */ + list = malloc((ancount + 1) * sizeof(char *)); + if (!list) { + errno = ENOMEM; + return NULL; + } + /* Parse the answers. */ + j = 0; + for (i = 0; i < ancount; i++) { + /* Parse the header of this answer. */ + skip = dn_skipname(p, eom); + if (skip < 0 || p + skip + 10 > eom) + break; + type = p[skip + 0] << 8 | p[skip + 1]; + class = p[skip + 2] << 8 | p[skip + 3]; + len = p[skip + 8] << 8 | p[skip + 9]; + p += skip + 10; + if (p + len > eom) { + errno = EMSGSIZE; + break; + } + /* Skip entries of the wrong class and type. */ + if (class != qclass || type != T_TXT) { + p += len; + continue; + } + /* Allocate space for this answer. */ + list[j] = malloc((size_t)len); + if (!list[j]) { + errno = ENOMEM; + break; + } + dst = list[j++]; + + /* Copy answer data into the allocated area. */ + eor = p + len; + while (p < eor) { + n = (unsigned char) *p++; + if (p + n > eor) { + errno = EMSGSIZE; + break; + } + memcpy(dst, p, (size_t)n); + p += n; + dst += n; + } + if (p < eor) { + errno = EMSGSIZE; + break; + } + *dst = 0; + } + + /* + * If we didn't terminate the loop normally, something + * went wrong. + */ + if (i < ancount) { + for (i = 0; i < j; i++) + free(list[i]); + free(list); + return NULL; + } + if (j == 0) { + errno = ENOENT; + free(list); + return NULL; + } + list[j] = NULL; + return list; +} + + /* + * COMPATIBILITY FUNCTIONS + */ + +static int inited = 0; +static void *context; +static int errval = HES_ER_UNINIT; + +int +hes_init() +{ + init_context(); + return errval; +} + +char * +hes_to_bind(name, type) + const char *name; + const char *type; +{ + static char *bindname; + if (init_context() < 0) + return NULL; + if (bindname) + free(bindname); + bindname = hesiod_to_bind(context, name, type); + if (!bindname) + translate_errors(); + return bindname; +} + +char ** +hes_resolve(name, type) + const char *name; + const char *type; +{ + static char **list; + + if (init_context() < 0) + return NULL; + + /* + * In the old Hesiod interface, the caller was responsible for + * freeing the returned strings but not the vector of strings itself. + */ + if (list) + free(list); + + list = hesiod_resolve(context, name, type); + if (!list) + translate_errors(); + return list; +} + +int +hes_error() +{ + return errval; +} + +void +hes_free(hp) + char **hp; +{ + hesiod_free_list(context, hp); +} + +static int +init_context() +{ + if (!inited) { + inited = 1; + if (hesiod_init(&context) < 0) { + errval = HES_ER_CONFIG; + return -1; + } + errval = HES_ER_OK; + } + return 0; +} + +static void +translate_errors() +{ + switch (errno) { + case ENOENT: + errval = HES_ER_NOTFOUND; + break; + case ECONNREFUSED: + case EMSGSIZE: + errval = HES_ER_NET; + break; + case ENOMEM: + default: + /* Not a good match, but the best we can do. */ + errval = HES_ER_CONFIG; + break; + } +} |