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resolv: Mirror the entire resolver configuration in struct resolv_conf

Browse Source 
This commit adds the remaining unchanging members (which are loaded
from /etc/resolv.conf) to struct resolv_conf.

The extended name server list is currently not used by the stub
resolver.  The switch depends on a cleanup: The _u._ext.nssocks
array stores just a single socket, and needs to be replaced with
a single socket value.

(The compatibility gethostname implementation does not use the
extended addres sort list, either.  Updating the compat code is
not worthwhile.)
This commit is contained in:
Florian Weimer 2017-06-30 20:19:10 +02:00
parent 3f853f22c8
commit a1c4eb8794
7 changed files with 572 additions and 116 deletions
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36
ChangeLog
View File

@ -1,3 +1,39 @@
2017-06-30 Florian Weimer <fweimer@redhat.com>
Mirror the entire resolver configuration in struct resolv_conf.
* resolv/resolv_context.h (__resolv_context_nameserver_count)
(__resolv_context_nameserver): New functions.
(__resolv_context_sort_count, __resolv_context_sort_entry):
Likewise.
* resolv/nss_dns/dns-host.c (getanswer_r): Add struct
resolv_context parameter.
(gethostbyname3_context, _nss_dns_gethostbyaddr2_r): Adjust.
(addrsort): Switch to struct resolv_context.
* resolv/resolv_conf.h (struct resolv_sortlist_entry): Define.
(struct resolv_conf): Add nameserver_list, nameserver_list_size,
sort_list, sort_list_size, options, retrans, retry, ndots members.
* resolv/resolv_conf.c (same_address_v4, same_address_v6)
(same_address): New functions.
(resolv_conf_matches): Compare the new array members.
(__resolv_conf_allocate): Allocate and copy the new array members.
(update_from_conf): Copy the entire configuration.
* resolv/res_init.c (struct nameserver_list, struct sort_list):
Define using dynarray.
(struct resolv_conf_parser): Add nameserver_list, sort_list,
template members.
(resolv_conf_parser_init): Add preinit argument. Initialize the
new members.
(resolv_conf_parser_free): Deallocate the new arrays.
(allocate_address_v4): New function.
(res_setoptions): Switch to struct resolv_conf_parser * parameter.
(res_vinit_1): Drop res_state parameter. Write all parsed date to
the parser object instead. Use allocate_address_v4 to allocate
IPv4 addresses.
(__res_vinit): Adjust.
* resolv/tst-resolv-res_init-skeleton.c (print_resp): Print the
extended name server list.
(test_cases): Adjust.
2017-06-30 Florian Weimer <fweimer@redhat.com>
[BZ #19569]

37
resolv/nss_dns/dns-host.c
View File

@ -108,7 +108,8 @@ typedef union querybuf
u_char buf[MAXPACKET];
} querybuf;
static enum nss_status getanswer_r (const querybuf *answer, int anslen,
static enum nss_status getanswer_r (struct resolv_context *ctx,
const querybuf *answer, int anslen,
const char *qname, int qtype,
struct hostent *result, char *buffer,
size_t buflen, int *errnop, int *h_errnop,
@ -264,8 +265,9 @@ gethostbyname3_context (struct resolv_context *ctx,
result->h_length = INADDRSZ;
}
status = getanswer_r (host_buffer.buf, n, name, type, result, buffer, buflen,
errnop, h_errnop, map, ttlp, canonp);
status = getanswer_r
(ctx, host_buffer.buf, n, name, type, result, buffer, buflen,
errnop, h_errnop, map, ttlp, canonp);
if (host_buffer.buf != orig_host_buffer)
free (host_buffer.buf);
return status;
@ -522,8 +524,9 @@ _nss_dns_gethostbyaddr2_r (const void *addr, socklen_t len, int af,
return errno == ECONNREFUSED ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
}
status = getanswer_r (host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
errnop, h_errnop, 0 /* XXX */, ttlp, NULL);
status = getanswer_r
(ctx, host_buffer.buf, n, qbuf, T_PTR, result, buffer, buflen,
errnop, h_errnop, 0 /* XXX */, ttlp, NULL);
if (host_buffer.buf != orig_host_buffer)
free (host_buffer.buf);
if (status != NSS_STATUS_SUCCESS)
@ -553,25 +556,27 @@ _nss_dns_gethostbyaddr_r (const void *addr, socklen_t len, int af,
errnop, h_errnop, NULL);
}
static void addrsort (char **ap, int num);
static void
addrsort (char **ap, int num)
addrsort (struct resolv_context *ctx, char **ap, int num)
{
int i, j;
char **p;
short aval[MAX_NR_ADDRS];
int needsort = 0;
size_t nsort = __resolv_context_sort_count (ctx);
p = ap;
if (num > MAX_NR_ADDRS)
num = MAX_NR_ADDRS;
for (i = 0; i < num; i++, p++)
{
for (j = 0 ; (unsigned)j < _res.nsort; j++)
if (_res.sort_list[j].addr.s_addr ==
(((struct in_addr *)(*p))->s_addr & _res.sort_list[j].mask))
break;
for (j = 0 ; (unsigned)j < nsort; j++)
{
struct resolv_sortlist_entry e
= __resolv_context_sort_entry (ctx, j);
if (e.addr.s_addr == (((struct in_addr *)(*p))->s_addr & e.mask))
break;
}
aval[i] = j;
if (needsort == 0 && i > 0 && j < aval[i-1])
needsort = i;
@ -598,7 +603,8 @@ addrsort (char **ap, int num)
}
static enum nss_status
getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
getanswer_r (struct resolv_context *ctx,
const querybuf *answer, int anslen, const char *qname, int qtype,
struct hostent *result, char *buffer, size_t buflen,
int *errnop, int *h_errnop, int map, int32_t *ttlp, char **canonp)
{
@ -961,8 +967,9 @@ getanswer_r (const querybuf *answer, int anslen, const char *qname, int qtype,
* in its return structures - should give it the "best"
* address in that case, not some random one
*/
if (_res.nsort && haveanswer > 1 && qtype == T_A)
addrsort (host_data->h_addr_ptrs, haveanswer);
if (haveanswer > 1 && qtype == T_A
&& __resolv_context_sort_count (ctx) > 0)
addrsort (ctx, host_data->h_addr_ptrs, haveanswer);
if (result->h_name == NULL)
{

219
resolv/res_init.c
View File

@ -104,7 +104,6 @@
#include <errno.h>
#include <resolv_conf.h>
static void res_setoptions (res_state, const char *);
static uint32_t net_mask (struct in_addr);
unsigned long long int __res_initstamp;
@ -124,28 +123,70 @@ is_sort_mask (char ch)
return ch == '/' || ch == '&';
}
/* 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 4
#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;
};
static void
resolv_conf_parser_init (struct resolv_conf_parser *parser)
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
@ -153,7 +194,23 @@ 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;
}
/* Try to obtain the domain name from the host name and store it in
@ -181,40 +238,17 @@ domain_from_hostname (char **result)
return true;
}
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 (res_state statp, bool preinit, FILE *fp,
struct resolv_conf_parser *parser)
res_vinit_1 (FILE *fp, struct resolv_conf_parser *parser)
{
char *cp;
size_t buffer_size = 0;
int nserv = 0; /* Number of nameservers read from file. */
bool have_serv6 = false;
bool haveenv = false;
int nsort = 0;
char *net;
if (!preinit)
{
statp->retrans = RES_TIMEOUT;
statp->retry = RES_DFLRETRY;
statp->options = RES_DEFAULT;
statp->id = res_randomid ();
}
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;
/* Allow user to override the local domain definition. */
if ((cp = getenv ("LOCALDOMAIN")) != NULL)
@ -350,19 +384,19 @@ res_vinit_1 (res_state statp, bool preinit, FILE *fp,
continue;
}
/* Read nameservers to query. */
if (MATCH (parser->buffer, "nameserver") && nserv < MAXNS)
if (MATCH (parser->buffer, "nameserver"))
{
struct in_addr a;
cp = parser->buffer + sizeof ("nameserver") - 1;
while (*cp == ' ' || *cp == '\t')
cp++;
struct sockaddr *sa;
if ((*cp != '\0') && (*cp != '\n') && __inet_aton (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
{
@ -392,13 +426,18 @@ res_vinit_1 (res_state statp, bool preinit, FILE *fp,
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;
}
continue;
}
@ -407,21 +446,22 @@ res_vinit_1 (res_state statp, bool preinit, FILE *fp,
struct in_addr a;
cp = parser->buffer + sizeof ("sortlist") - 1;
while (nsort < MAXRESOLVSORT)
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;
struct resolv_sortlist_entry e;
if (__inet_aton (net, &a))
{
statp->sort_list[nsort].addr = a;
e.addr = a;
if (is_sort_mask (separator))
{
*cp++ = separator;
@ -432,15 +472,13 @@ res_vinit_1 (res_state statp, bool preinit, FILE *fp,
separator = *cp;
*cp = 0;
if (__inet_aton (net, &a))
statp->sort_list[nsort].mask = a.s_addr;
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;
}
@ -448,23 +486,22 @@ res_vinit_1 (res_state statp, bool preinit, FILE *fp,
}
if (MATCH (parser->buffer, "options"))
{
res_setoptions (statp, parser->buffer + sizeof ("options") - 1);
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 (search_list_size (&parser->search_list) == 0)
@ -481,15 +518,16 @@ res_vinit_1 (res_state statp, bool preinit, FILE *fp,
}
if ((cp = getenv ("RES_OPTIONS")) != NULL)
res_setoptions (statp, cp);
res_setoptions (parser, cp);
if (search_list_has_failed (&parser->search_list))
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;
}
statp->options |= RES_INIT;
return true;
}
@ -525,17 +563,27 @@ __res_vinit (res_state statp, int preinit)
}
struct resolv_conf_parser parser;
resolv_conf_parser_init (&parser);
bool ok = res_vinit_1 (statp, preinit, fp, &parser);
if (preinit)
{
resolv_conf_parser_init (&parser, statp);
statp->id = res_randomid ();
}
else
resolv_conf_parser_init (&parser, NULL);
bool ok = res_vinit_1 (fp, &parser);
if (ok)
{
struct resolv_conf init =
{
.search_list = search_list_begin (&parser.search_list),
.search_list_size = search_list_size (&parser.search_list),
};
struct resolv_conf *conf = __resolv_conf_allocate (&init);
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);
struct resolv_conf *conf = __resolv_conf_allocate (&parser.template);
if (conf == NULL)
ok = false;
else
@ -547,18 +595,13 @@ __res_vinit (res_state statp, int preinit)
resolv_conf_parser_free (&parser);
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;
}
return 0;
return -1;
else
return 0;
}
static void
res_setoptions (res_state statp, const char *options)
res_setoptions (struct resolv_conf_parser *parser, const char *options)
{
const char *cp = options;
@ -572,25 +615,25 @@ res_setoptions (res_state statp, const char *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
{
@ -616,9 +659,9 @@ res_setoptions (res_state statp, const char *options)
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;
}
}

223
resolv/resolv_conf.c
View File

@ -128,11 +128,80 @@ resolv_conf_get_1 (const struct __res_state *resp)
return conf;
}
/* Return true if both IPv4 addresses are equal. */
static bool
same_address_v4 (const struct sockaddr_in *left,
const struct sockaddr_in *right)
{
return left->sin_addr.s_addr == right->sin_addr.s_addr
&& left->sin_port == right->sin_port;
}
/* Return true if both IPv6 addresses are equal. This ignores the
flow label. */
static bool
same_address_v6 (const struct sockaddr_in6 *left,
const struct sockaddr_in6 *right)
{
return memcmp (&left->sin6_addr, &right->sin6_addr,
sizeof (left->sin6_addr)) == 0
&& left->sin6_port == right->sin6_port
&& left->sin6_scope_id == right->sin6_scope_id;
}
static bool
same_address (const struct sockaddr *left, const struct sockaddr *right)
{
if (left->sa_family != right->sa_family)
return false;
switch (left->sa_family)
{
case AF_INET:
return same_address_v4 ((const struct sockaddr_in *) left,
(const struct sockaddr_in *) right);
case AF_INET6:
return same_address_v6 ((const struct sockaddr_in6 *) left,
(const struct sockaddr_in6 *) right);
}
return false;
}
/* Check that *RESP and CONF match. Used by __resolv_conf_get. */
static bool
resolv_conf_matches (const struct __res_state *resp,
const struct resolv_conf *conf)
{
/* NB: Do not compare the options, retrans, retry, ndots. These can
be changed by applicaiton. */
/* Check that the name servers in *RESP have not been modified by
the application. */
{
size_t nserv = conf->nameserver_list_size;
if (nserv > MAXNS)
nserv = MAXNS;
/* _ext.nscount is 0 until initialized by res_send.c. */
if (resp->nscount != nserv
&& (resp->_u._ext.nscount != 0 && resp->_u._ext.nscount != nserv))
return false;
for (size_t i = 0; i < nserv; ++i)
{
if (resp->nsaddr_list[i].sin_family == 0)
{
if (resp->_u._ext.nsaddrs[i]->sin6_family != AF_INET6)
return false;
if (!same_address ((struct sockaddr *) resp->_u._ext.nsaddrs[i],
conf->nameserver_list[i]))
return false;
}
else if (resp->nsaddr_list[i].sin_family != AF_INET)
return false;
else if (!same_address ((struct sockaddr *) &resp->nsaddr_list[i],
conf->nameserver_list[i]))
return false;
}
}
/* Check that the search list in *RESP has not been modified by the
application. */
{
@ -161,6 +230,18 @@ resolv_conf_matches (const struct __res_state *resp,
}
}
}
/* Check that the sort list has not been modified. */
{
size_t nsort = conf->sort_list_size;
if (nsort > MAXRESOLVSORT)
nsort = MAXRESOLVSORT;
for (size_t i = 0; i < nsort; ++i)
if (resp->sort_list[i].addr.s_addr != conf->sort_list[i].addr.s_addr
|| resp->sort_list[i].mask != conf->sort_list[i].mask)
return false;
}
return true;
}
@ -190,7 +271,28 @@ __resolv_conf_put (struct resolv_conf *conf)
struct resolv_conf *
__resolv_conf_allocate (const struct resolv_conf *init)
{
/* Space needed by the strings. */
/* Allocate in decreasing order of alignment. */
_Static_assert (__alignof__ (const char *const *)
<= __alignof__ (struct resolv_conf), "alignment");
_Static_assert (__alignof__ (struct sockaddr_in6)
<= __alignof__ (const char *const *), "alignment");
_Static_assert (__alignof__ (struct sockaddr_in)
== __alignof__ (struct sockaddr_in6), "alignment");
_Static_assert (__alignof__ (struct resolv_sortlist_entry)
<= __alignof__ (struct sockaddr_in), "alignment");
/* Space needed by the nameserver addresses. */
size_t address_space = 0;
for (size_t i = 0; i < init->nameserver_list_size; ++i)
if (init->nameserver_list[i]->sa_family == AF_INET)
address_space += sizeof (struct sockaddr_in);
else
{
assert (init->nameserver_list[i]->sa_family == AF_INET6);
address_space += sizeof (struct sockaddr_in6);
}
/* Space needed by the search list strings. */
size_t string_space = 0;
for (size_t i = 0; i < init->search_list_size; ++i)
string_space += strlen (init->search_list[i]) + 1;
@ -199,7 +301,10 @@ __resolv_conf_allocate (const struct resolv_conf *init)
void *ptr;
struct alloc_buffer buffer = alloc_buffer_allocate
(sizeof (struct resolv_conf)
+ init->nameserver_list_size * sizeof (init->nameserver_list[0])
+ address_space
+ init->search_list_size * sizeof (init->search_list[0])
+ init->sort_list_size * sizeof (init->sort_list[0])
+ string_space,
&ptr);
struct resolv_conf *conf
@ -211,16 +316,57 @@ __resolv_conf_allocate (const struct resolv_conf *init)
/* Initialize the contents. */
conf->__refcount = 1;
conf->retrans = init->retrans;
conf->retry = init->retry;
conf->options = init->options;
conf->ndots = init->ndots;
conf->initstamp = __res_initstamp;
/* Allocate and fill the search list array. */
/* Allocate the arrays with pointers. These must come first because
they have the highets alignment. */
conf->nameserver_list_size = init->nameserver_list_size;
const struct sockaddr **nameserver_array = alloc_buffer_alloc_array
(&buffer, const struct sockaddr *, init->nameserver_list_size);
conf->nameserver_list = nameserver_array;
conf->search_list_size = init->search_list_size;
const char **search_array = alloc_buffer_alloc_array
(&buffer, const char *, init->search_list_size);
conf->search_list = search_array;
/* Fill the name server list array. */
for (size_t i = 0; i < init->nameserver_list_size; ++i)
if (init->nameserver_list[i]->sa_family == AF_INET)
{
struct sockaddr_in *sa = alloc_buffer_alloc
(&buffer, struct sockaddr_in);
*sa = *(struct sockaddr_in *) init->nameserver_list[i];
nameserver_array[i] = (struct sockaddr *) sa;
}
else
{
struct sockaddr_in6 *sa = alloc_buffer_alloc
(&buffer, struct sockaddr_in6);
*sa = *(struct sockaddr_in6 *) init->nameserver_list[i];
nameserver_array[i] = (struct sockaddr *) sa;
}
/* Allocate and fill the sort list array. */
{
conf->sort_list_size = init->sort_list_size;
struct resolv_sortlist_entry *array = alloc_buffer_alloc_array
(&buffer, struct resolv_sortlist_entry, init->sort_list_size);
conf->sort_list = array;
for (size_t i = 0; i < init->sort_list_size; ++i)
array[i] = init->sort_list[i];
}
/* Fill the search list array. This must come last because the
strings are the least aligned part of the allocation. */
{
conf->search_list_size = init->search_list_size;
const char **array = alloc_buffer_alloc_array
(&buffer, const char *, init->search_list_size);
conf->search_list = array;
for (size_t i = 0; i < init->search_list_size; ++i)
array[i] = alloc_buffer_copy_string (&buffer, init->search_list[i]);
search_array[i] = alloc_buffer_copy_string
(&buffer, init->search_list[i]);
}
assert (!alloc_buffer_has_failed (&buffer));
@ -231,6 +377,56 @@ __resolv_conf_allocate (const struct resolv_conf *init)
static __attribute__ ((nonnull (1, 2), warn_unused_result)) bool
update_from_conf (struct __res_state *resp, const struct resolv_conf *conf)
{
resp->defdname[0] = '\0';
resp->pfcode = 0;
resp->_vcsock = -1;
resp->_flags = 0;
resp->ipv6_unavail = false;
resp->__glibc_unused_qhook = NULL;
resp->__glibc_unused_rhook = NULL;
resp->retrans = conf->retrans;
resp->retry = conf->retry;
resp->options = conf->options;
resp->ndots = conf->ndots;
/* Copy the name server addresses. */
{
resp->nscount = 0;
resp->_u._ext.nscount = 0;
size_t nserv = conf->nameserver_list_size;
if (nserv > MAXNS)
nserv = MAXNS;
for (size_t i = 0; i < nserv; i++)
{
if (conf->nameserver_list[i]->sa_family == AF_INET)
{
resp->nsaddr_list[i]
= *(struct sockaddr_in *)conf->nameserver_list[i];
resp->_u._ext.nsaddrs[i] = NULL;
}
else
{
assert (conf->nameserver_list[i]->sa_family == AF_INET6);
resp->nsaddr_list[i].sin_family = 0;
/* Make a defensive copy of the name server address, in
case the application overwrites it. */
struct sockaddr_in6 *sa = malloc (sizeof (*sa));
if (sa == NULL)
{
for (size_t j = 0; j < i; ++j)
free (resp->_u._ext.nsaddrs[j]);
return false;
}
*sa = *(struct sockaddr_in6 *)conf->nameserver_list[i];
resp->_u._ext.nsaddrs[i] = sa;
}
resp->_u._ext.nssocks[i] = -1;
}
resp->nscount = nserv;
/* Leave resp->_u._ext.nscount at 0. res_send.c handles this. */
}
/* Fill in the prefix of the search list. It is truncated either at
MAXDNSRCH, or if reps->defdname has insufficient space. */
{
@ -249,6 +445,19 @@ update_from_conf (struct __res_state *resp, const struct resolv_conf *conf)
resp->dnsrch[i] = NULL;
}
/* Copy the sort list. */
{
size_t nsort = conf->sort_list_size;
if (nsort > MAXRESOLVSORT)
nsort = MAXRESOLVSORT;
for (size_t i = 0; i < nsort; ++i)
{
resp->sort_list[i].addr = conf->sort_list[i].addr;
resp->sort_list[i].mask = conf->sort_list[i].mask;
}
resp->nsort = nsort;
}
/* The overlapping parts of both configurations should agree after
initialization. */
assert (resolv_conf_matches (resp, conf));

23
resolv/resolv_conf.h
View File

@ -19,9 +19,17 @@
#ifndef RESOLV_STATE_H
#define RESOLV_STATE_H
#include <netinet/in.h>
#include <stdbool.h>
#include <stddef.h>
/* This type corresponds to members of the _res.sort_list array. */
struct resolv_sortlist_entry
{
struct in_addr addr;
uint32_t mask;
};
/* Extended resolver state associated with res_state objects. Client
code can reach this state through a struct resolv_context
object. */
@ -36,9 +44,24 @@ struct resolv_conf
zero. For internal use within resolv_conf only. */
size_t __refcount;
/* List of IPv4 and IPv6 name server addresses. */
const struct sockaddr **nameserver_list;
size_t nameserver_list_size;
/* The domain names forming the search list. */
const char *const *search_list;
size_t search_list_size;
/* IPv4 address preference rules. */
const struct resolv_sortlist_entry *sort_list;
size_t sort_list_size;
/* _res.options has type unsigned long, but we can only use 32 bits
for portability across all architectures. */
unsigned int options;
unsigned int retrans; /* Timeout. */
unsigned int retry; /* Number of times to retry. */
unsigned int ndots; /* Dots needed for initial non-search query. */
};
/* The functions below are for use by the res_init resolv.conf parser

61
resolv/resolv_context.h
View File

@ -112,6 +112,67 @@ __resolv_context_search_list (const struct resolv_context *ctx, size_t index)
return NULL;
}
/* Return the number of name servers. */
static __attribute__ ((nonnull (1), unused)) size_t
__resolv_context_nameserver_count (const struct resolv_context *ctx)
{
if (ctx->conf != NULL)
return ctx->conf->nameserver_list_size;
else
return ctx->resp->nscount;
}
/* Return a pointer to the socket address of the name server INDEX, or
NULL if the index is out of bounds. */
static __attribute__ ((nonnull (1), unused)) const struct sockaddr *
__resolv_context_nameserver (const struct resolv_context *ctx, size_t index)
{
if (ctx->conf != NULL)
{
if (index < ctx->conf->nameserver_list_size)
return ctx->conf->nameserver_list[index];
}
else
if (index < ctx->resp->nscount)
{
if (ctx->resp->nsaddr_list[index].sin_family != 0)
return (const struct sockaddr *) &ctx->resp->nsaddr_list[index];
else
return (const struct sockaddr *) &ctx->resp->_u._ext.nsaddrs[index];
}
return NULL;
}
/* Return the number of sort list entries. */
static __attribute__ ((nonnull (1), unused)) size_t
__resolv_context_sort_count (const struct resolv_context *ctx)
{
if (ctx->conf != NULL)
return ctx->conf->sort_list_size;
else
return ctx->resp->nsort;
}
/* Return the sort list entry at INDEX. */
static __attribute__ ((nonnull (1), unused)) struct resolv_sortlist_entry
__resolv_context_sort_entry (const struct resolv_context *ctx, size_t index)
{
if (ctx->conf != NULL)
{
if (index < ctx->conf->sort_list_size)
return ctx->conf->sort_list[index];
/* Fall through. */
}
else if (index < ctx->resp->nsort)
return (struct resolv_sortlist_entry)
{
.addr = ctx->resp->sort_list[index].addr,
.mask = ctx->resp->sort_list[index].mask,
};
return (struct resolv_sortlist_entry) { .mask = 0, };
}
/* Called during thread shutdown to free the associated resolver
context (mostly in response to cancellation, otherwise the
__resolv_context_get/__resolv_context_put pairing will already have

89
resolv/tst-resolv-res_init-skeleton.c
View File

@ -242,6 +242,46 @@ print_resp (FILE *fp, res_state resp)
}
}
/* The extended name server list. */
{
size_t i = 0;
while (true)
{
const struct sockaddr *addr = __resolv_context_nameserver (ctx, i);
if (addr == NULL)
break;
size_t addrlen;
switch (addr->sa_family)
{
case AF_INET:
addrlen = sizeof (struct sockaddr_in);
break;
case AF_INET6:
addrlen = sizeof (struct sockaddr_in6);
break;
default:
FAIL_EXIT1 ("invalid address family %d", addr->sa_family);
}
char host[NI_MAXHOST];
char service[NI_MAXSERV];
int ret = getnameinfo (addr, addrlen,
host, sizeof (host), service, sizeof (service),
NI_NUMERICHOST | NI_NUMERICSERV);
if (ret != 0)
{
if (ret == EAI_SYSTEM)
fprintf (fp, "; error: getnameinfo: %m\n");
else
fprintf (fp, "; error: getnameinfo: %s\n", gai_strerror (ret));
}
else
fprintf (fp, "; nameserver[%zu]: [%s]:%s\n", i, host, service);
++i;
}
}
TEST_VERIFY (!ferror (fp));
__resolv_context_put (ctx);
@ -391,12 +431,14 @@ struct test_case test_cases[] =
.expected = "search example.com\n"
"; search[0]: example.com\n"
"nameserver 127.0.0.1\n"
"; nameserver[0]: [127.0.0.1]:53\n"
},
{.name = "empty file with LOCALDOMAIN",
.conf = "",
.expected = "search example.net\n"
"; search[0]: example.net\n"
"nameserver 127.0.0.1\n",
"nameserver 127.0.0.1\n"
"; nameserver[0]: [127.0.0.1]:53\n",
.localdomain = "example.net",
},
{.name = "empty file with RES_OPTIONS",
@ -404,7 +446,8 @@ struct test_case test_cases[] =
.expected = "options attempts:5 edns0\n"
"search example.com\n"
"; search[0]: example.com\n"
"nameserver 127.0.0.1\n",
"nameserver 127.0.0.1\n"
"; nameserver[0]: [127.0.0.1]:53\n",
.res_options = "edns0 attempts:5",
},
{.name = "empty file with RES_OPTIONS and LOCALDOMAIN",
@ -412,7 +455,8 @@ struct test_case test_cases[] =
.expected = "options attempts:5 edns0\n"
"search example.org\n"
"; search[0]: example.org\n"
"nameserver 127.0.0.1\n",
"nameserver 127.0.0.1\n"
"; nameserver[0]: [127.0.0.1]:53\n",
.localdomain = "example.org",
.res_options = "edns0 attempts:5",
},
@ -424,6 +468,7 @@ struct test_case test_cases[] =
"; search[0]: corp.example.com\n"
"; search[1]: example.com\n"
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
{.name = "whitespace",
.conf = "# This test covers comment and whitespace processing "
@ -440,6 +485,8 @@ struct test_case test_cases[] =
"; search[1]: example.com\n"
"nameserver 192.0.2.1\n"
"nameserver 192.0.2.2\n"
"; nameserver[0]: [192.0.2.1]:53\n"
"; nameserver[1]: [192.0.2.2]:53\n"
},
{.name = "domain",
.conf = "domain example.net\n"
@ -447,6 +494,7 @@ struct test_case test_cases[] =
.expected = "search example.net\n"
"; search[0]: example.net\n"
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
{.name = "domain space",
.conf = "domain example.net \n"
@ -454,6 +502,7 @@ struct test_case test_cases[] =
.expected = "search example.net\n"
"; search[0]: example.net\n"
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
{.name = "domain tab",
.conf = "domain example.net\t\n"
@ -461,6 +510,7 @@ struct test_case test_cases[] =
.expected = "search example.net\n"
"; search[0]: example.net\n"
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
{.name = "domain override",
.conf = "search example.com example.org\n"
@ -469,6 +519,7 @@ struct test_case test_cases[] =
.expected = "search example.net\n"
"; search[0]: example.net\n"
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
{.name = "option values, multiple servers",
.conf = "options\tinet6\tndots:3 edns0\tattempts:5\ttimeout:19\n"
@ -485,6 +536,9 @@ struct test_case test_cases[] =
"nameserver 192.0.2.1\n"
"nameserver ::1\n"
"nameserver 192.0.2.2\n"
"; nameserver[0]: [192.0.2.1]:53\n"
"; nameserver[1]: [::1]:53\n"
"; nameserver[2]: [192.0.2.2]:53\n"
},
{.name = "out-of-range option vales",
.conf = "options use-vc timeout:999 attempts:999 ndots:99\n"
@ -493,6 +547,7 @@ struct test_case test_cases[] =
"search example.com\n"
"; search[0]: example.com\n"
"nameserver 127.0.0.1\n"
"; nameserver[0]: [127.0.0.1]:53\n"
},
{.name = "repeated directives",
.conf = "options ndots:3 use-vc\n"
@ -505,6 +560,7 @@ struct test_case test_cases[] =
"search example.org\n"
"; search[0]: example.org\n"
"nameserver 127.0.0.1\n"
"; nameserver[0]: [127.0.0.1]:53\n"
},
{.name = "many name servers, sortlist",
.conf = "options single-request\n"
@ -528,6 +584,14 @@ struct test_case test_cases[] =
"nameserver 192.0.2.1\n"
"nameserver 192.0.2.2\n"
"nameserver 192.0.2.3\n"
"; nameserver[0]: [192.0.2.1]:53\n"
"; nameserver[1]: [192.0.2.2]:53\n"
"; nameserver[2]: [192.0.2.3]:53\n"
"; nameserver[3]: [192.0.2.4]:53\n"
"; nameserver[4]: [192.0.2.5]:53\n"
"; nameserver[5]: [192.0.2.6]:53\n"
"; nameserver[6]: [192.0.2.7]:53\n"
"; nameserver[7]: [192.0.2.8]:53\n"
},
{.name = "IPv4 and IPv6 nameservers",
.conf = "options single-request\n"
@ -554,6 +618,14 @@ struct test_case test_cases[] =
"nameserver 192.0.2.1\n"
"nameserver 2001:db8::2\n"
"nameserver 192.0.2.3\n"
"; nameserver[0]: [192.0.2.1]:53\n"
"; nameserver[1]: [2001:db8::2]:53\n"
"; nameserver[2]: [192.0.2.3]:53\n"
"; nameserver[3]: [2001:db8::4]:53\n"
"; nameserver[4]: [192.0.2.5]:53\n"
"; nameserver[5]: [2001:db8::6]:53\n"
"; nameserver[6]: [192.0.2.7]:53\n"
"; nameserver[7]: [2001:db8::8]:53\n",
},
{.name = "garbage after nameserver",
.conf = "nameserver 192.0.2.1 garbage\n"
@ -563,6 +635,8 @@ struct test_case test_cases[] =
"; search[0]: example.com\n"
"nameserver 192.0.2.1\n"
"nameserver 192.0.2.3\n"
"; nameserver[0]: [192.0.2.1]:53\n"
"; nameserver[1]: [192.0.2.3]:53\n"
},
{.name = "RES_OPTIONS is cummulative",
.conf = "options timeout:7 ndots:2 use-vc\n"
@ -570,7 +644,8 @@ struct test_case test_cases[] =
.expected = "options ndots:3 timeout:7 attempts:5 use-vc edns0\n"
"search example.com\n"
"; search[0]: example.com\n"
"nameserver 192.0.2.1\n",
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n",
.res_options = "attempts:5 ndots:3 edns0 ",
},
{.name = "many search list entries (bug 19569)",
@ -588,7 +663,8 @@ struct test_case test_cases[] =
"; search[5]: example.com\n"
"; search[6]: example.org\n"
"; search[7]: example.net\n"
"nameserver 192.0.2.1\n",
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
{.name = "very long search list entries (bug 21475)",
.conf = "nameserver 192.0.2.1\n"
@ -603,7 +679,8 @@ struct test_case test_cases[] =
"; search[2]: " H63 "." D63 ".example.net\n"
#undef H63
#undef D63
"nameserver 192.0.2.1\n",
"nameserver 192.0.2.1\n"
"; nameserver[0]: [192.0.2.1]:53\n"
},
{ NULL }
};