/* Resolver state initialization and resolv.conf parsing.
- Copyright (C) 1995-2017 Free Software Foundation, Inc.
+ Copyright (C) 1995-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
#include <ctype.h>
#include <netdb.h>
#include <resolv/resolv-internal.h>
+#include <res_hconf.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <sys/types.h>
#include <inet/net-internal.h>
#include <errno.h>
+#include <resolv_conf.h>
-static void res_setoptions (res_state, const char *, const char *);
static uint32_t net_mask (struct in_addr);
-unsigned long long int __res_initstamp attribute_hidden;
-
int
res_ninit (res_state statp)
{
return ch == '/' || ch == '&';
}
-/* Internal helper function for __res_vinit, to aid with resource
- deallocation and error handling. Return true on success, false on
- failure. */
+/* Array of name server addresses. */
+#define DYNARRAY_STRUCT nameserver_list
+#define DYNARRAY_ELEMENT const struct sockaddr *
+#define DYNARRAY_ELEMENT_FREE(e) free ((struct sockaddr *) *(e))
+#define DYNARRAY_INITIAL_SIZE 3
+#define DYNARRAY_PREFIX nameserver_list_
+#include <malloc/dynarray-skeleton.c>
+
+/* Array of strings for the search array. The backing store is
+ managed separately. */
+#define DYNARRAY_STRUCT search_list
+#define DYNARRAY_ELEMENT const char *
+#define DYNARRAY_INITIAL_SIZE 6
+#define DYNARRAY_PREFIX search_list_
+#include <malloc/dynarray-skeleton.c>
+
+/* Array of name server addresses. */
+#define DYNARRAY_STRUCT sort_list
+#define DYNARRAY_ELEMENT struct resolv_sortlist_entry
+#define DYNARRAY_INITIAL_SIZE 0
+#define DYNARRAY_PREFIX sort_list_
+#include <malloc/dynarray-skeleton.c>
+
+/* resolv.conf parser state and results. */
+struct resolv_conf_parser
+{
+ char *buffer; /* Temporary buffer for reading lines. */
+
+ struct nameserver_list nameserver_list; /* Nameserver addresses. */
+
+ char *search_list_store; /* Backing storage for search list entries. */
+ struct search_list search_list; /* Points into search_list_store. */
+
+ struct sort_list sort_list; /* Address preference sorting list. */
+
+ /* Configuration template. The non-array elements are filled in
+ directly. The array elements are updated prior to the call to
+ __resolv_conf_attach. */
+ struct resolv_conf template;
+};
+
+/* Return true if *PREINIT contains actual preinitialization. */
static bool
-res_vinit_1 (res_state statp, bool preinit, FILE *fp)
+has_preinit_values (const struct __res_state *preinit)
{
- char *cp, **pp;
- char buf[BUFSIZ];
- int nserv = 0; /* Number of nameservers read from file. */
- bool have_serv6 = false;
- bool haveenv = false;
- bool havesearch = false;
- int nsort = 0;
- char *net;
- statp->_u._ext.initstamp = __res_initstamp;
+ return (preinit->retrans != 0 && preinit->retrans != RES_TIMEOUT)
+ || (preinit->retry != 0 && preinit->retry != RES_DFLRETRY)
+ || (preinit->options != 0
+ && (preinit->options & ~RES_INIT) != RES_DEFAULT);
+}
+
+static void
+resolv_conf_parser_init (struct resolv_conf_parser *parser,
+ const struct __res_state *preinit)
+{
+ parser->buffer = NULL;
+ parser->search_list_store = NULL;
+ nameserver_list_init (&parser->nameserver_list);
+ search_list_init (&parser->search_list);
+ sort_list_init (&parser->sort_list);
+
+ if (preinit != NULL)
+ {
+ parser->template.retrans = preinit->retrans;
+ parser->template.retry = preinit->retry;
+ parser->template.options = preinit->options | RES_INIT;
+ }
+ else
+ {
+ parser->template.retrans = RES_TIMEOUT;
+ parser->template.retry = RES_DFLRETRY;
+ parser->template.options = RES_DEFAULT | RES_INIT;
+ }
+ parser->template.ndots = 1;
+}
+
+static void
+resolv_conf_parser_free (struct resolv_conf_parser *parser)
+{
+ free (parser->buffer);
+ free (parser->search_list_store);
+ nameserver_list_free (&parser->nameserver_list);
+ search_list_free (&parser->search_list);
+ sort_list_free (&parser->sort_list);
+}
+
+/* Allocate a struct sockaddr_in object on the heap, with the
+ specified address and port. */
+static struct sockaddr *
+allocate_address_v4 (struct in_addr a, uint16_t port)
+{
+ struct sockaddr_in *sa4 = malloc (sizeof (*sa4));
+ if (sa4 == NULL)
+ return NULL;
+ sa4->sin_family = AF_INET;
+ sa4->sin_addr = a;
+ sa4->sin_port = htons (port);
+ return (struct sockaddr *) sa4;
+}
- if (!preinit)
+/* Try to obtain the domain name from the host name and store it in
+ *RESULT. Return false on memory allocation failure. If the domain
+ name cannot be determined for any other reason, write NULL to
+ *RESULT and return true. */
+static bool
+domain_from_hostname (char **result)
+{
+ char buf[256];
+ /* gethostbyname may not terminate the buffer. */
+ buf[sizeof (buf) - 1] = '\0';
+ if (__gethostname (buf, sizeof (buf) - 1) == 0)
{
- statp->retrans = RES_TIMEOUT;
- statp->retry = RES_DFLRETRY;
- statp->options = RES_DEFAULT;
- statp->id = res_randomid ();
+ char *dot = strchr (buf, '.');
+ if (dot != NULL)
+ {
+ *result = __strdup (dot + 1);
+ if (*result == NULL)
+ return false;
+ return true;
+ }
}
+ *result = NULL;
+ return true;
+}
- statp->nscount = 0;
- statp->defdname[0] = '\0';
- statp->ndots = 1;
- statp->pfcode = 0;
- statp->_vcsock = -1;
- statp->_flags = 0;
- statp->__glibc_unused_qhook = NULL;
- statp->__glibc_unused_rhook = NULL;
- statp->_u._ext.nscount = 0;
- for (int n = 0; n < MAXNS; n++)
- statp->_u._ext.nsaddrs[n] = NULL;
+static void res_setoptions (struct resolv_conf_parser *, const char *options);
+
+/* Internal helper function for __res_vinit, to aid with resource
+ deallocation and error handling. Return true on success, false on
+ failure. */
+static bool
+res_vinit_1 (FILE *fp, struct resolv_conf_parser *parser)
+{
+ char *cp;
+ size_t buffer_size = 0;
+ bool haveenv = false;
/* Allow user to override the local domain definition. */
if ((cp = getenv ("LOCALDOMAIN")) != NULL)
{
- strncpy (statp->defdname, cp, sizeof (statp->defdname) - 1);
- statp->defdname[sizeof (statp->defdname) - 1] = '\0';
+ /* The code below splits the string in place. */
+ cp = __strdup (cp);
+ if (cp == NULL)
+ return false;
+ free (parser->search_list_store);
+ parser->search_list_store = cp;
haveenv = true;
+ /* The string will be truncated as needed below. */
+ search_list_add (&parser->search_list, cp);
+
/* Set search list to be blank-separated strings from rest of
env value. Permits users of LOCALDOMAIN to still have a
search list, and anyone to set the one that they want to use
as an individual (even more important now that the rfc1535
stuff restricts searches). */
- cp = statp->defdname;
- pp = statp->dnsrch;
- *pp++ = cp;
- for (int n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++)
+ for (bool in_name = true; *cp != '\0'; cp++)
{
if (*cp == '\n')
- break;
+ {
+ *cp = '\0';
+ break;
+ }
else if (*cp == ' ' || *cp == '\t')
{
- *cp = 0;
- n = 1;
+ *cp = '\0';
+ in_name = false;
}
- else if (n > 0)
+ else if (!in_name)
{
- *pp++ = cp;
- n = 0;
- havesearch = true;
+ search_list_add (&parser->search_list, cp);
+ in_name = true;
}
}
- /* Null terminate last domain if there are excess. */
- while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
- cp++;
- *cp = '\0';
- *pp++ = 0;
}
#define MATCH(line, name) \
- (!strncmp (line, name, sizeof (name) - 1) \
- && (line[sizeof (name) - 1] == ' ' \
- || line[sizeof (name) - 1] == '\t'))
+ (!strncmp ((line), name, sizeof (name) - 1) \
+ && ((line)[sizeof (name) - 1] == ' ' \
+ || (line)[sizeof (name) - 1] == '\t'))
if (fp != NULL)
{
/* No threads use this stream. */
__fsetlocking (fp, FSETLOCKING_BYCALLER);
/* Read the config file. */
- while (__fgets_unlocked (buf, sizeof (buf), fp) != NULL)
+ while (true)
{
+ {
+ ssize_t ret = __getline (&parser->buffer, &buffer_size, fp);
+ if (ret <= 0)
+ {
+ if (_IO_ferror_unlocked (fp))
+ return false;
+ else
+ break;
+ }
+ }
+
/* Skip comments. */
- if (*buf == ';' || *buf == '#')
+ if (*parser->buffer == ';' || *parser->buffer == '#')
continue;
/* Read default domain name. */
- if (MATCH (buf, "domain"))
+ if (MATCH (parser->buffer, "domain"))
{
if (haveenv)
/* LOCALDOMAIN overrides the configuration file. */
continue;
- cp = buf + sizeof ("domain") - 1;
+ cp = parser->buffer + sizeof ("domain") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
if ((*cp == '\0') || (*cp == '\n'))
continue;
- strncpy (statp->defdname, cp, sizeof (statp->defdname) - 1);
- statp->defdname[sizeof (statp->defdname) - 1] = '\0';
- if ((cp = strpbrk (statp->defdname, " \t\n")) != NULL)
+
+ cp = __strdup (cp);
+ if (cp == NULL)
+ return false;
+ free (parser->search_list_store);
+ parser->search_list_store = cp;
+ search_list_clear (&parser->search_list);
+ search_list_add (&parser->search_list, cp);
+ /* Replace trailing whitespace. */
+ if ((cp = strpbrk (cp, " \t\n")) != NULL)
*cp = '\0';
- havesearch = false;
continue;
}
/* Set search list. */
- if (MATCH (buf, "search"))
+ if (MATCH (parser->buffer, "search"))
{
if (haveenv)
/* LOCALDOMAIN overrides the configuration file. */
continue;
- cp = buf + sizeof ("search") - 1;
+ cp = parser->buffer + sizeof ("search") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
if ((*cp == '\0') || (*cp == '\n'))
continue;
- strncpy (statp->defdname, cp, sizeof (statp->defdname) - 1);
- statp->defdname[sizeof (statp->defdname) - 1] = '\0';
- if ((cp = strchr (statp->defdname, '\n')) != NULL)
- *cp = '\0';
+
+ {
+ char *p = strchr (cp, '\n');
+ if (p != NULL)
+ *p = '\0';
+ }
+ cp = __strdup (cp);
+ if (cp == NULL)
+ return false;
+ free (parser->search_list_store);
+ parser->search_list_store = cp;
+
+ /* The string is truncated below. */
+ search_list_clear (&parser->search_list);
+ search_list_add (&parser->search_list, cp);
+
/* Set search list to be blank-separated strings on rest
of line. */
- cp = statp->defdname;
- pp = statp->dnsrch;
- *pp++ = cp;
- for (int n = 0; *cp && pp < statp->dnsrch + MAXDNSRCH; cp++)
+ for (bool in_name = true; *cp != '\0'; cp++)
{
if (*cp == ' ' || *cp == '\t')
{
- *cp = 0;
- n = 1;
+ *cp = '\0';
+ in_name = false;
}
- else if (n)
+ else if (!in_name)
{
- *pp++ = cp;
- n = 0;
+ search_list_add (&parser->search_list, cp);
+ in_name = true;
}
}
- /* Null terminate last domain if there are excess. */
- while (*cp != '\0' && *cp != ' ' && *cp != '\t')
- cp++;
- *cp = '\0';
- *pp++ = 0;
- havesearch = true;
continue;
}
/* Read nameservers to query. */
- if (MATCH (buf, "nameserver") && nserv < MAXNS)
+ if (MATCH (parser->buffer, "nameserver"))
{
struct in_addr a;
- cp = buf + sizeof ("nameserver") - 1;
+ cp = parser->buffer + sizeof ("nameserver") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
- if ((*cp != '\0') && (*cp != '\n') && __inet_aton (cp, &a))
+
+ /* Ignore trailing contents on the name server line. */
+ {
+ char *el;
+ if ((el = strpbrk (cp, " \t\n")) != NULL)
+ *el = '\0';
+ }
+
+ struct sockaddr *sa;
+ if ((*cp != '\0') && (*cp != '\n') && __inet_aton_exact (cp, &a))
{
- statp->nsaddr_list[nserv].sin_addr = a;
- statp->nsaddr_list[nserv].sin_family = AF_INET;
- statp->nsaddr_list[nserv].sin_port = htons (NAMESERVER_PORT);
- nserv++;
+ sa = allocate_address_v4 (a, NAMESERVER_PORT);
+ if (sa == NULL)
+ return false;
}
else
{
struct in6_addr a6;
char *el;
-
- if ((el = strpbrk (cp, " \t\n")) != NULL)
- *el = '\0';
if ((el = strchr (cp, SCOPE_DELIMITER)) != NULL)
*el = '\0';
if ((*cp != '\0') && (__inet_pton (AF_INET6, cp, &a6) > 0))
sa6 = malloc (sizeof (*sa6));
if (sa6 == NULL)
- return -1;
+ return false;
sa6->sin6_family = AF_INET6;
sa6->sin6_port = htons (NAMESERVER_PORT);
compatibility. */
__inet6_scopeid_pton
(&a6, el + 1, &sa6->sin6_scope_id);
-
- statp->nsaddr_list[nserv].sin_family = 0;
- statp->_u._ext.nsaddrs[nserv] = sa6;
- statp->_u._ext.nssocks[nserv] = -1;
- have_serv6 = true;
- nserv++;
+ sa = (struct sockaddr *) sa6;
+ }
+ else
+ /* IPv6 address parse failure. */
+ sa = NULL;
+ }
+ if (sa != NULL)
+ {
+ const struct sockaddr **p = nameserver_list_emplace
+ (&parser->nameserver_list);
+ if (p != NULL)
+ *p = sa;
+ else
+ {
+ free (sa);
+ return false;
}
}
continue;
}
- if (MATCH (buf, "sortlist"))
+ if (MATCH (parser->buffer, "sortlist"))
{
struct in_addr a;
- cp = buf + sizeof ("sortlist") - 1;
- while (nsort < MAXRESOLVSORT)
+ cp = parser->buffer + sizeof ("sortlist") - 1;
+ while (true)
{
while (*cp == ' ' || *cp == '\t')
cp++;
if (*cp == '\0' || *cp == '\n' || *cp == ';')
break;
- net = cp;
+ char *net = cp;
while (*cp && !is_sort_mask (*cp) && *cp != ';'
&& isascii (*cp) && !isspace (*cp))
cp++;
char separator = *cp;
*cp = 0;
- if (__inet_aton (net, &a))
+ struct resolv_sortlist_entry e;
+ if (__inet_aton_exact (net, &a))
{
- statp->sort_list[nsort].addr = a;
+ e.addr = a;
if (is_sort_mask (separator))
{
*cp++ = separator;
cp++;
separator = *cp;
*cp = 0;
- if (__inet_aton (net, &a))
- statp->sort_list[nsort].mask = a.s_addr;
+ if (__inet_aton_exact (net, &a))
+ e.mask = a.s_addr;
else
- statp->sort_list[nsort].mask
- = net_mask (statp->sort_list[nsort].addr);
+ e.mask = net_mask (e.addr);
}
else
- statp->sort_list[nsort].mask
- = net_mask (statp->sort_list[nsort].addr);
- nsort++;
+ e.mask = net_mask (e.addr);
+ sort_list_add (&parser->sort_list, e);
}
*cp = separator;
}
continue;
}
- if (MATCH (buf, "options"))
+ if (MATCH (parser->buffer, "options"))
{
- res_setoptions (statp, buf + sizeof ("options") - 1, "conf");
+ res_setoptions (parser, parser->buffer + sizeof ("options") - 1);
continue;
}
}
- statp->nscount = nserv;
- if (have_serv6)
- /* We try IPv6 servers again. */
- statp->ipv6_unavail = false;
- statp->nsort = nsort;
fclose (fp);
}
- if (__glibc_unlikely (statp->nscount == 0))
+ if (__glibc_unlikely (nameserver_list_size (&parser->nameserver_list) == 0))
{
- statp->nsaddr.sin_addr = __inet_makeaddr (IN_LOOPBACKNET, 1);
- statp->nsaddr.sin_family = AF_INET;
- statp->nsaddr.sin_port = htons (NAMESERVER_PORT);
- statp->nscount = 1;
+ const struct sockaddr **p
+ = nameserver_list_emplace (&parser->nameserver_list);
+ if (p == NULL)
+ return false;
+ *p = allocate_address_v4 (__inet_makeaddr (IN_LOOPBACKNET, 1),
+ NAMESERVER_PORT);
+ if (*p == NULL)
+ return false;
}
- if (statp->defdname[0] == 0
- && __gethostname (buf, sizeof (statp->defdname) - 1) == 0
- && (cp = strchr (buf, '.')) != NULL)
- strcpy (statp->defdname, cp + 1);
- /* Find components of local domain that might be searched. */
- if (!havesearch)
+ if (search_list_size (&parser->search_list) == 0)
{
- pp = statp->dnsrch;
- *pp++ = statp->defdname;
- *pp = NULL;
-
+ char *domain;
+ if (!domain_from_hostname (&domain))
+ return false;
+ if (domain != NULL)
+ {
+ free (parser->search_list_store);
+ parser->search_list_store = domain;
+ search_list_add (&parser->search_list, domain);
+ }
}
if ((cp = getenv ("RES_OPTIONS")) != NULL)
- res_setoptions (statp, cp, "env");
- statp->options |= RES_INIT;
- return 0;
+ res_setoptions (parser, cp);
+
+ if (nameserver_list_has_failed (&parser->nameserver_list)
+ || search_list_has_failed (&parser->search_list)
+ || sort_list_has_failed (&parser->sort_list))
+ {
+ __set_errno (ENOMEM);
+ return false;
+ }
+
+ return true;
}
-/* Set up default settings. If the /etc/resolv.conf configuration
- file exist, the values there will have precedence. Otherwise, the
- server address is set to INADDR_LOOPBACK and the default domain
- name comes from gethostname. The RES_OPTIONS and LOCALDOMAIN
- environment variables can be used to override some settings.
- Return 0 if completes successfully, -1 on error. */
-int
-__res_vinit (res_state statp, int preinit)
+struct resolv_conf *
+__resolv_conf_load (struct __res_state *preinit)
{
+ /* Ensure that /etc/hosts.conf has been loaded (once). */
+ _res_hconf_init ();
+
FILE *fp = fopen (_PATH_RESCONF, "rce");
if (fp == NULL)
switch (errno)
default:
/* Other errors refer to resource allocation problems and
need to be handled by the application. */
- return -1;
+ return NULL;
}
- if (!res_vinit_1 (statp, preinit, fp))
+
+ struct resolv_conf_parser parser;
+ resolv_conf_parser_init (&parser, preinit);
+
+ struct resolv_conf *conf = NULL;
+ if (res_vinit_1 (fp, &parser))
+ {
+ parser.template.nameserver_list
+ = nameserver_list_begin (&parser.nameserver_list);
+ parser.template.nameserver_list_size
+ = nameserver_list_size (&parser.nameserver_list);
+ parser.template.search_list = search_list_begin (&parser.search_list);
+ parser.template.search_list_size
+ = search_list_size (&parser.search_list);
+ parser.template.sort_list = sort_list_begin (&parser.sort_list);
+ parser.template.sort_list_size = sort_list_size (&parser.sort_list);
+ conf = __resolv_conf_allocate (&parser.template);
+ }
+ resolv_conf_parser_free (&parser);
+
+ return conf;
+}
+
+/* Set up default settings. If the /etc/resolv.conf configuration
+ file exist, the values there will have precedence. Otherwise, the
+ server address is set to INADDR_LOOPBACK and the default domain
+ name comes from gethostname. The RES_OPTIONS and LOCALDOMAIN
+ environment variables can be used to override some settings.
+ Return 0 if completes successfully, -1 on error. */
+int
+__res_vinit (res_state statp, int preinit)
+{
+ struct resolv_conf *conf;
+ if (preinit && has_preinit_values (statp))
+ /* For the preinit case, we cannot use the cached configuration
+ because some settings could be different. */
+ conf = __resolv_conf_load (statp);
+ else
+ conf = __resolv_conf_get_current ();
+ if (conf == NULL)
+ return -1;
+
+ bool ok = __resolv_conf_attach (statp, conf);
+ __resolv_conf_put (conf);
+ if (ok)
{
- /* Deallocate the name server addresses which have been
- allocated. */
- for (int n = 0; n < MAXNS; n++)
- free (statp->_u._ext.nsaddrs[n]);
- return -1;
+ if (preinit)
+ statp->id = res_randomid ();
+ return 0;
}
- return 0;
+ else
+ return -1;
}
static void
-res_setoptions (res_state statp, const char *options, const char *source)
+res_setoptions (struct resolv_conf_parser *parser, const char *options)
{
const char *cp = options;
{
int i = atoi (cp + sizeof ("ndots:") - 1);
if (i <= RES_MAXNDOTS)
- statp->ndots = i;
+ parser->template.ndots = i;
else
- statp->ndots = RES_MAXNDOTS;
+ parser->template.ndots = RES_MAXNDOTS;
}
else if (!strncmp (cp, "timeout:", sizeof ("timeout:") - 1))
{
int i = atoi (cp + sizeof ("timeout:") - 1);
if (i <= RES_MAXRETRANS)
- statp->retrans = i;
+ parser->template.retrans = i;
else
- statp->retrans = RES_MAXRETRANS;
+ parser->template.retrans = RES_MAXRETRANS;
}
else if (!strncmp (cp, "attempts:", sizeof ("attempts:") - 1))
{
int i = atoi (cp + sizeof ("attempts:") - 1);
if (i <= RES_MAXRETRY)
- statp->retry = i;
+ parser->template.retry = i;
else
- statp->retry = RES_MAXRETRY;
+ parser->template.retry = RES_MAXRETRY;
}
else
{
{ STRnLEN ("single-request"), 0, RES_SNGLKUP },
{ STRnLEN ("no_tld_query"), 0, RES_NOTLDQUERY },
{ STRnLEN ("no-tld-query"), 0, RES_NOTLDQUERY },
+ { STRnLEN ("no-reload"), 0, RES_NORELOAD },
{ STRnLEN ("use-vc"), 0, RES_USEVC }
};
#define noptions (sizeof (options) / sizeof (options[0]))
if (strncmp (cp, options[i].str, options[i].len) == 0)
{
if (options[i].clear)
- statp->options &= options[i].flag;
+ parser->template.options &= options[i].flag;
else
- statp->options |= options[i].flag;
+ parser->template.options |= options[i].flag;
break;
}
}
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