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Diffstat (limited to 'contrib/isc-dhcp/common/resolv.c')
| -rw-r--r-- | contrib/isc-dhcp/common/resolv.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/contrib/isc-dhcp/common/resolv.c b/contrib/isc-dhcp/common/resolv.c new file mode 100644 index 000000000000..396f9ef747f3 --- /dev/null +++ b/contrib/isc-dhcp/common/resolv.c @@ -0,0 +1,212 @@ +/* resolv.c + + Parser for /etc/resolv.conf file. */ + +/* + * Copyright (c) 1996-2001 Internet Software Consortium. + * 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. Neither the name of The Internet Software Consortium 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 INTERNET SOFTWARE CONSORTIUM 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 INTERNET SOFTWARE CONSORTIUM 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. + * + * This software has been written for the Internet Software Consortium + * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc. + * To learn more about the Internet Software Consortium, see + * ``http://www.isc.org/''. To learn more about Vixie Enterprises, + * see ``http://www.vix.com''. To learn more about Nominum, Inc., see + * ``http://www.nominum.com''. + */ + +#ifndef lint +static char copyright[] = +"$Id: resolv.c,v 1.16 2001/05/02 06:39:43 mellon Exp $ Copyright (c) 1996-2001 The Internet Software Consortium. All rights reserved.\n"; +#endif /* not lint */ + +#include "dhcpd.h" + +struct name_server *name_servers; +struct domain_search_list *domains; +char path_resolv_conf [] = _PATH_RESOLV_CONF; + +void read_resolv_conf (parse_time) + TIME parse_time; +{ + int file; + struct parse *cfile; + const char *val; + int token; + int declaration = 0; + struct name_server *sp, *sl, *ns; + struct domain_search_list *dp, *dl, *nd; + struct iaddr *iaddr; + + if ((file = open (path_resolv_conf, O_RDONLY)) < 0) { + log_error ("Can't open %s: %m", path_resolv_conf); + return; + } + + cfile = (struct parse *)0; + new_parse (&cfile, file, (char *)0, 0, path_resolv_conf, 1); + + do { + token = next_token (&val, (unsigned *)0, cfile); + if (token == END_OF_FILE) + break; + else if (token == EOL) + continue; + else if (token == DOMAIN || token == SEARCH) { + do { + struct domain_search_list *nd, **dp; + char *dn; + + dn = parse_host_name (cfile); + if (!dn) + break; + + dp = &domains; + for (nd = domains; nd; nd = nd -> next) { + dp = &nd -> next; + if (!strcmp (nd -> domain, dn)) + break; + } + if (!nd) { + nd = new_domain_search_list (MDL); + if (!nd) + log_fatal ("No memory for %s", + dn); + nd -> next = + (struct domain_search_list *)0; + *dp = nd; + nd -> domain = dn; + dn = (char *)0; + } + nd -> rcdate = parse_time; + token = peek_token (&val, + (unsigned *)0, cfile); + } while (token != EOL); + if (token != EOL) { + parse_warn (cfile, + "junk after domain declaration"); + skip_to_semi (cfile); + } + token = next_token (&val, (unsigned *)0, cfile); + } else if (token == NAMESERVER) { + struct name_server *ns, **sp; + struct iaddr iaddr; + + parse_ip_addr (cfile, &iaddr); + + sp = &name_servers; + for (ns = name_servers; ns; ns = ns -> next) { + sp = &ns -> next; + if (!memcmp (&ns -> addr.sin_addr, + iaddr.iabuf, iaddr.len)) + break; + } + if (!ns) { + ns = new_name_server (MDL); + if (!ns) + log_fatal ("No memory for nameserver %s", + piaddr (iaddr)); + ns -> next = (struct name_server *)0; + *sp = ns; + memcpy (&ns -> addr.sin_addr, + iaddr.iabuf, iaddr.len); +#ifdef HAVE_SA_LEN + ns -> addr.sin_len = sizeof ns -> addr; +#endif + ns -> addr.sin_family = AF_INET; + ns -> addr.sin_port = htons (53); + memset (ns -> addr.sin_zero, 0, + sizeof ns -> addr.sin_zero); + } + ns -> rcdate = parse_time; + skip_to_semi (cfile); + } else + skip_to_semi (cfile); /* Ignore what we don't grok. */ + } while (1); + token = next_token (&val, (unsigned *)0, cfile); + + /* Lose servers that are no longer in /etc/resolv.conf. */ + sl = (struct name_server *)0; + for (sp = name_servers; sp; sp = ns) { + ns = sp -> next; + if (sp -> rcdate != parse_time) { + if (sl) + sl -> next = sp -> next; + else + name_servers = sp -> next; + /* We can't actually free the name server structure, + because somebody might be hanging on to it. If + your /etc/resolv.conf file changes a lot, this + could be a noticable memory leak. */ + } else + sl = sp; + } + + /* Lose domains that are no longer in /etc/resolv.conf. */ + dl = (struct domain_search_list *)0; + for (dp = domains; dp; dp = nd) { + nd = dp -> next; + if (dp -> rcdate != parse_time) { + if (dl) + dl -> next = dp -> next; + else + domains = dp -> next; + free_domain_search_list (dp, MDL); + } else + dl = dp; + } + close (file); + end_parse (&cfile); +} + +/* Pick a name server from the /etc/resolv.conf file. */ + +struct name_server *first_name_server () +{ + FILE *rc; + static TIME rcdate; + struct stat st; + + /* Check /etc/resolv.conf and reload it if it's changed. */ + if (cur_time > rcdate) { + if (stat (path_resolv_conf, &st) < 0) { + log_error ("Can't stat %s", path_resolv_conf); + return (struct name_server *)0; + } + if (st.st_mtime > rcdate) { + char rcbuf [512]; + char *s, *t, *u; + rcdate = cur_time + 1; + + read_resolv_conf (rcdate); + } + } + + return name_servers; +} |