diff options
Diffstat (limited to 'mit-pthreads/net/res_search.c')
| -rw-r--r-- | mit-pthreads/net/res_search.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/mit-pthreads/net/res_search.c b/mit-pthreads/net/res_search.c new file mode 100644 index 00000000000..2c84f0d68f3 --- /dev/null +++ b/mit-pthreads/net/res_search.c @@ -0,0 +1,168 @@ +/* + * Copyright (c) 1985, 1988 Regents of the University of California. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +/*static char *sccsid = "from: @(#)res_search.c 6.45 (Berkeley) 2/24/91";*/ +static char *rcsid = "$Id$"; +#endif /* LIBC_SCCS and not lint */ + +#include <pthread.h> +#include <string.h> +#include <stdio.h> +#include <stdlib.h> +#include <resolv.h> +#include <netdb.h> +#include "res_internal.h" + +static char *search_aliases(const char *name, char *buf, int bufsize); + +int res_search(const char *name, int class, int type, unsigned char *answer, + int anslen) +{ + struct res_data *data; + const char *p; + int num_dots, len, result, no_data = 0, error; + char buf[2 * MAXDNAME + 2], *domain, **dptr, *alias; + + data = _res_init(); + if (!data) + return -1; + + /* Count the dots in name, and get a pointer to the end of name. */ + num_dots = 0; + for (p = name; *p; p++) { + if (*p == '.') + num_dots++; + } + len = p - name; + + /* If there aren't any dots, check to see if name is an alias for + * another host. If so, try the resolved alias as a fully-qualified + * name. */ + alias = search_aliases(name, buf, sizeof(buf)); + if (alias != NULL) + return res_query(alias, class, type, answer, anslen); + + /* If there's a trailing dot, try to strip it off and query the name. */ + if (len > 0 && p[-1] == '.') { + if (len > sizeof(buf)) { + /* It's too long; just query the original name. */ + return res_query(name, class, type, answer, anslen); + } else { + /* Copy the name without the trailing dot and query. */ + memcpy(buf, name, len - 1); + buf[len] = 0; + return res_query(buf, class, type, answer, anslen); + } + } + + if (data->state.options & RES_DNSRCH) { + /* If RES_DNSRCH is set, query all the domains until we get a + * definitive answer. */ + for (dptr = data->state.dnsrch; *dptr; dptr++) { + domain = *dptr; + sprintf(buf, "%.*s.%.*s", MAXDNAME, name, MAXDNAME, domain); + result = res_query(buf, class, type, answer, anslen); + if (result > 0) + return result; + if (data->errval == NO_DATA) + no_data = 1; + else if (data->errval != HOST_NOT_FOUND) + break; + } + } else if (num_dots == 0 && data->state.options & RES_DEFNAMES) { + /* If RES_DEFNAMES is set and there is no dot, query the default + * domain. */ + domain = data->state.defdname; + sprintf(buf, "%.*s.%.%s", MAXDNAME, name, MAXDNAME, domain); + result = res_query(buf, class, type, answer, anslen); + if (result > 0) + return result; + if (data->errval == NO_DATA) + no_data = 1; + } + + /* If all the domain queries failed, try the name as fully-qualified. + * Only do this if there is at least one dot in the name. */ + if (num_dots > 0) { + result = res_query(name, class, type, answer, anslen); + if (result > 0) + return result; + } + + if (no_data) + data->errval = NO_DATA; + + return -1; +} + +static char *search_aliases(const char *name, char *buf, int bufsize) +{ + FILE *fp; + char *filename, *p; + int len; + + filename = getenv("HOSTALIASES"); + if (filename == NULL) + return NULL; + + fp = fopen(filename, "r"); + if (fp == NULL) + return NULL; + + len = strlen(name); + while (fgets(buf, bufsize, fp)) { + + /* Get the first word from the buffer. */ + p = buf; + while (*p && !isspace(*p)) + p++; + if (!*p) + break; + + /* Null-terminate the first word and compare it with the name. */ + *p = 0; + if (strcasecmp(buf, name) != 0) + continue; + + p++; + while (isspace(*p)) + p++; + fclose(fp); + return (*p) ? p : NULL; + } + + fclose(fp); + return NULL; +} + |