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Systemd/src/libsystemd/sd-dns.c

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2005-2008 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <fcntl.h>
#include <signal.h>
#include <unistd.h>
#include <sys/select.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <pwd.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <dirent.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <stdint.h>
#include <pthread.h>
#include <sys/prctl.h>
#include "sd-dns.h"
#include "util.h"
#define MAX_WORKERS 16
#define MAX_QUERIES 256
#define BUFSIZE (10240)
typedef enum {
REQUEST_ADDRINFO,
RESPONSE_ADDRINFO,
REQUEST_NAMEINFO,
RESPONSE_NAMEINFO,
REQUEST_RES_QUERY,
REQUEST_RES_SEARCH,
RESPONSE_RES,
REQUEST_TERMINATE,
RESPONSE_DIED
} query_type_t;
enum {
REQUEST_RECV_FD = 0,
REQUEST_SEND_FD = 1,
RESPONSE_RECV_FD = 2,
RESPONSE_SEND_FD = 3,
MESSAGE_FD_MAX = 4
};
struct asyncns {
int fds[MESSAGE_FD_MAX];
pthread_t workers[MAX_WORKERS];
unsigned valid_workers;
unsigned current_id, current_index;
asyncns_query_t* queries[MAX_QUERIES];
asyncns_query_t *done_head, *done_tail;
int n_queries;
int dead;
};
struct asyncns_query {
asyncns_t *asyncns;
int done;
unsigned id;
query_type_t type;
asyncns_query_t *done_next, *done_prev;
int ret;
int _errno;
int _h_errno;
struct addrinfo *addrinfo;
char *serv, *host;
void *userdata;
};
typedef struct rheader {
query_type_t type;
unsigned id;
size_t length;
} rheader_t;
typedef struct addrinfo_request {
struct rheader header;
int hints_is_null;
int ai_flags;
int ai_family;
int ai_socktype;
int ai_protocol;
size_t node_len, service_len;
} addrinfo_request_t;
typedef struct addrinfo_response {
struct rheader header;
int ret;
int _errno;
int _h_errno;
/* followed by addrinfo_serialization[] */
} addrinfo_response_t;
typedef struct addrinfo_serialization {
int ai_flags;
int ai_family;
int ai_socktype;
int ai_protocol;
size_t ai_addrlen;
size_t canonname_len;
/* Followed by ai_addr amd ai_canonname with variable lengths */
} addrinfo_serialization_t;
typedef struct nameinfo_request {
struct rheader header;
int flags;
socklen_t sockaddr_len;
int gethost, getserv;
} nameinfo_request_t;
typedef struct nameinfo_response {
struct rheader header;
size_t hostlen, servlen;
int ret;
int _errno;
int _h_errno;
} nameinfo_response_t;
typedef struct res_request {
struct rheader header;
int class;
int type;
size_t dname_len;
} res_request_t;
typedef struct res_response {
struct rheader header;
int ret;
int _errno;
int _h_errno;
} res_response_t;
typedef union packet {
rheader_t rheader;
addrinfo_request_t addrinfo_request;
addrinfo_response_t addrinfo_response;
nameinfo_request_t nameinfo_request;
nameinfo_response_t nameinfo_response;
res_request_t res_request;
res_response_t res_response;
} packet_t;
static int send_died(int out_fd) {
rheader_t rh = {};
assert(out_fd > 0);
rh.type = RESPONSE_DIED;
rh.id = 0;
rh.length = sizeof(rh);
return send(out_fd, &rh, rh.length, MSG_NOSIGNAL);
}
static void *serialize_addrinfo(void *p, const struct addrinfo *ai, size_t *length, size_t maxlength) {
addrinfo_serialization_t s;
size_t cnl, l;
assert(p);
assert(ai);
assert(length);
assert(*length <= maxlength);
cnl = (ai->ai_canonname ? strlen(ai->ai_canonname)+1 : 0);
l = sizeof(addrinfo_serialization_t) + ai->ai_addrlen + cnl;
if (*length + l > maxlength)
return NULL;
s.ai_flags = ai->ai_flags;
s.ai_family = ai->ai_family;
s.ai_socktype = ai->ai_socktype;
s.ai_protocol = ai->ai_protocol;
s.ai_addrlen = ai->ai_addrlen;
s.canonname_len = cnl;
memcpy((uint8_t*) p, &s, sizeof(addrinfo_serialization_t));
memcpy((uint8_t*) p + sizeof(addrinfo_serialization_t), ai->ai_addr, ai->ai_addrlen);
if (ai->ai_canonname)
strcpy((char*) p + sizeof(addrinfo_serialization_t) + ai->ai_addrlen, ai->ai_canonname);
*length += l;
return (uint8_t*) p + l;
}
static int send_addrinfo_reply(int out_fd, unsigned id, int ret, struct addrinfo *ai, int _errno, int _h_errno) {
addrinfo_response_t data[BUFSIZE/sizeof(addrinfo_response_t) + 1] = {};
addrinfo_response_t *resp = data;
assert(out_fd >= 0);
resp->header.type = RESPONSE_ADDRINFO;
resp->header.id = id;
resp->header.length = sizeof(addrinfo_response_t);
resp->ret = ret;
resp->_errno = _errno;
resp->_h_errno = _h_errno;
if (ret == 0 && ai) {
void *p = data + 1;
struct addrinfo *k;
for (k = ai; k; k = k->ai_next) {
p = serialize_addrinfo(p, k, &resp->header.length, (char*) data + BUFSIZE - (char*) p);
if (!p) {
resp->ret = EAI_MEMORY;
break;
}
}
}
if (ai)
freeaddrinfo(ai);
return send(out_fd, resp, resp->header.length, MSG_NOSIGNAL);
}
static int send_nameinfo_reply(int out_fd, unsigned id, int ret, const char *host, const char *serv, int _errno, int _h_errno) {
nameinfo_response_t data[BUFSIZE/sizeof(nameinfo_response_t) + 1] = {};
size_t hl, sl;
nameinfo_response_t *resp = data;
assert(out_fd >= 0);
sl = serv ? strlen(serv)+1 : 0;
hl = host ? strlen(host)+1 : 0;
resp->header.type = RESPONSE_NAMEINFO;
resp->header.id = id;
resp->header.length = sizeof(nameinfo_response_t) + hl + sl;
resp->ret = ret;
resp->_errno = _errno;
resp->_h_errno = _h_errno;
resp->hostlen = hl;
resp->servlen = sl;
assert(sizeof(data) >= resp->header.length);
if (host)
memcpy((uint8_t *)data + sizeof(nameinfo_response_t), host, hl);
if (serv)
memcpy((uint8_t *)data + sizeof(nameinfo_response_t) + hl, serv, sl);
return send(out_fd, resp, resp->header.length, MSG_NOSIGNAL);
}
static int send_res_reply(int out_fd, unsigned id, const unsigned char *answer, int ret, int _errno, int _h_errno) {
res_response_t data[BUFSIZE/sizeof(res_response_t) + 1] = {};
res_response_t *resp = data;
assert(out_fd >= 0);
resp->header.type = RESPONSE_RES;
resp->header.id = id;
resp->header.length = sizeof(res_response_t) + (ret < 0 ? 0 : ret);
resp->ret = ret;
resp->_errno = _errno;
resp->_h_errno = _h_errno;
assert(sizeof(data) >= resp->header.length);
if (ret > 0)
memcpy((uint8_t *)data + sizeof(res_response_t), answer, ret);
return send(out_fd, resp, resp->header.length, MSG_NOSIGNAL);
}
static int handle_request(int out_fd, const packet_t *packet, size_t length) {
const rheader_t *req;
assert(out_fd >= 0);
req = &packet->rheader;
assert(req);
assert(length >= sizeof(rheader_t));
assert(length == req->length);
switch (req->type) {
case REQUEST_ADDRINFO: {
struct addrinfo ai = {}, *result = NULL;
const addrinfo_request_t *ai_req = &packet->addrinfo_request;
const char *node, *service;
int ret;
assert(length >= sizeof(addrinfo_request_t));
assert(length == sizeof(addrinfo_request_t) + ai_req->node_len + ai_req->service_len);
ai.ai_flags = ai_req->ai_flags;
ai.ai_family = ai_req->ai_family;
ai.ai_socktype = ai_req->ai_socktype;
ai.ai_protocol = ai_req->ai_protocol;
node = ai_req->node_len ? (const char*) ai_req + sizeof(addrinfo_request_t) : NULL;
service = ai_req->service_len ? (const char*) ai_req + sizeof(addrinfo_request_t) + ai_req->node_len : NULL;
ret = getaddrinfo(node, service,
ai_req->hints_is_null ? NULL : &ai,
&result);
/* send_addrinfo_reply() frees result */
return send_addrinfo_reply(out_fd, req->id, ret, result, errno, h_errno);
}
case REQUEST_NAMEINFO: {
int ret;
const nameinfo_request_t *ni_req = &packet->nameinfo_request;
char hostbuf[NI_MAXHOST], servbuf[NI_MAXSERV];
struct sockaddr_storage sa;
assert(length >= sizeof(nameinfo_request_t));
assert(length == sizeof(nameinfo_request_t) + ni_req->sockaddr_len);
memcpy(&sa, (const uint8_t *) ni_req + sizeof(nameinfo_request_t), ni_req->sockaddr_len);
ret = getnameinfo((struct sockaddr *)&sa, ni_req->sockaddr_len,
ni_req->gethost ? hostbuf : NULL, ni_req->gethost ? sizeof(hostbuf) : 0,
ni_req->getserv ? servbuf : NULL, ni_req->getserv ? sizeof(servbuf) : 0,
ni_req->flags);
return send_nameinfo_reply(out_fd, req->id, ret,
ret == 0 && ni_req->gethost ? hostbuf : NULL,
ret == 0 && ni_req->getserv ? servbuf : NULL,
errno, h_errno);
}
case REQUEST_RES_QUERY:
case REQUEST_RES_SEARCH: {
int ret;
HEADER answer[BUFSIZE/sizeof(HEADER) + 1];
const res_request_t *res_req = &packet->res_request;
const char *dname;
assert(length >= sizeof(res_request_t));
assert(length == sizeof(res_request_t) + res_req->dname_len);
dname = (const char *) req + sizeof(res_request_t);
if (req->type == REQUEST_RES_QUERY)
ret = res_query(dname, res_req->class, res_req->type, (unsigned char *) answer, BUFSIZE);
else
ret = res_search(dname, res_req->class, res_req->type, (unsigned char *) answer, BUFSIZE);
return send_res_reply(out_fd, req->id, (unsigned char *) answer, ret, errno, h_errno);
}
case REQUEST_TERMINATE:
/* Quit */
return -1;
default:
;
}
return 0;
}
static void* thread_worker(void *p) {
asyncns_t *asyncns = p;
sigset_t fullset;
/* No signals in this thread please */
sigfillset(&fullset);
pthread_sigmask(SIG_BLOCK, &fullset, NULL);
while (!asyncns->dead) {
packet_t buf[BUFSIZE/sizeof(packet_t) + 1];
ssize_t length;
length = recv(asyncns->fds[REQUEST_RECV_FD], buf, sizeof(buf), 0);
if (length <= 0) {
if (length < 0 && (errno == EAGAIN || errno == EINTR))
continue;
break;
}
if (asyncns->dead)
break;
if (handle_request(asyncns->fds[RESPONSE_SEND_FD], buf, (size_t) length) < 0)
break;
}
send_died(asyncns->fds[RESPONSE_SEND_FD]);
return NULL;
}
asyncns_t* asyncns_new(unsigned n_proc) {
int i;
asyncns_t *asyncns = NULL;
assert(n_proc >= 1);
if (n_proc > MAX_WORKERS)
n_proc = MAX_WORKERS;
asyncns = malloc(sizeof(asyncns_t));
if (!asyncns) {
errno = ENOMEM;
goto fail;
}
asyncns->dead = 0;
asyncns->valid_workers = 0;
for (i = 0; i < MESSAGE_FD_MAX; i++)
asyncns->fds[i] = -1;
memset(asyncns->queries, 0, sizeof(asyncns->queries));
#ifdef SOCK_CLOEXEC
if (socketpair(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, asyncns->fds) < 0 ||
socketpair(PF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, asyncns->fds+2) < 0) {
/* Try again, without SOCK_CLOEXEC */
if (errno == EINVAL) {
#endif
if (socketpair(PF_UNIX, SOCK_DGRAM, 0, asyncns->fds) < 0 ||
socketpair(PF_UNIX, SOCK_DGRAM, 0, asyncns->fds+2) < 0)
goto fail;
#ifdef SOCK_CLOEXEC
} else
goto fail;
}
#endif
for (i = 0; i < MESSAGE_FD_MAX; i++)
fd_cloexec(asyncns->fds[i], true);
for (asyncns->valid_workers = 0; asyncns->valid_workers < n_proc; asyncns->valid_workers++) {
int r;
r = pthread_create(&asyncns->workers[asyncns->valid_workers], NULL, thread_worker, asyncns);
if (r) {
errno = r;
goto fail;
}
}
asyncns->current_index = asyncns->current_id = 0;
asyncns->done_head = asyncns->done_tail = NULL;
asyncns->n_queries = 0;
fd_nonblock(asyncns->fds[RESPONSE_RECV_FD], true);
return asyncns;
fail:
if (asyncns)
asyncns_free(asyncns);
return NULL;
}
void asyncns_free(asyncns_t *asyncns) {
int i;
int saved_errno = errno;
unsigned p;
assert(asyncns);
asyncns->dead = 1;
if (asyncns->fds[REQUEST_SEND_FD] >= 0) {
rheader_t req = {};
req.type = REQUEST_TERMINATE;
req.length = sizeof(req);
req.id = 0;
/* Send one termination packet for each worker */
for (p = 0; p < asyncns->valid_workers; p++)
send(asyncns->fds[REQUEST_SEND_FD], &req, req.length, MSG_NOSIGNAL);
}
/* Now terminate them and wait until they are gone. */
for (p = 0; p < asyncns->valid_workers; p++) {
for (;;) {
if (pthread_join(asyncns->workers[p], NULL) != EINTR)
break;
}
}
/* Close all communication channels */
for (i = 0; i < MESSAGE_FD_MAX; i++)
if (asyncns->fds[i] >= 0)
close(asyncns->fds[i]);
for (p = 0; p < MAX_QUERIES; p++)
if (asyncns->queries[p])
asyncns_cancel(asyncns, asyncns->queries[p]);
free(asyncns);
errno = saved_errno;
}
int asyncns_fd(asyncns_t *asyncns) {
assert(asyncns);
return asyncns->fds[RESPONSE_RECV_FD];
}
static asyncns_query_t *lookup_query(asyncns_t *asyncns, unsigned id) {
asyncns_query_t *q;
assert(asyncns);
q = asyncns->queries[id % MAX_QUERIES];
if (q)
if (q->id == id)
return q;
return NULL;
}
static void complete_query(asyncns_t *asyncns, asyncns_query_t *q) {
assert(asyncns);
assert(q);
assert(!q->done);
q->done = 1;
if ((q->done_prev = asyncns->done_tail))
asyncns->done_tail->done_next = q;
else
asyncns->done_head = q;
asyncns->done_tail = q;
q->done_next = NULL;
}
static const void *unserialize_addrinfo(const void *p, struct addrinfo **ret_ai, size_t *length) {
addrinfo_serialization_t s;
size_t l;
struct addrinfo *ai;
assert(p);
assert(ret_ai);
assert(length);
if (*length < sizeof(addrinfo_serialization_t))
return NULL;
memcpy(&s, p, sizeof(s));
l = sizeof(addrinfo_serialization_t) + s.ai_addrlen + s.canonname_len;
if (*length < l)
return NULL;
ai = malloc(sizeof(struct addrinfo));
if (!ai)
goto fail;
ai->ai_addr = NULL;
ai->ai_canonname = NULL;
ai->ai_next = NULL;
if (s.ai_addrlen && !(ai->ai_addr = malloc(s.ai_addrlen)))
goto fail;
if (s.canonname_len && !(ai->ai_canonname = malloc(s.canonname_len)))
goto fail;
ai->ai_flags = s.ai_flags;
ai->ai_family = s.ai_family;
ai->ai_socktype = s.ai_socktype;
ai->ai_protocol = s.ai_protocol;
ai->ai_addrlen = s.ai_addrlen;
if (ai->ai_addr)
memcpy(ai->ai_addr, (const uint8_t*) p + sizeof(addrinfo_serialization_t), s.ai_addrlen);
if (ai->ai_canonname)
memcpy(ai->ai_canonname, (const uint8_t*) p + sizeof(addrinfo_serialization_t) + s.ai_addrlen, s.canonname_len);
*length -= l;
*ret_ai = ai;
return (const uint8_t*) p + l;
fail:
if (ai)
asyncns_freeaddrinfo(ai);
return NULL;
}
static int handle_response(asyncns_t *asyncns, const packet_t *packet, size_t length) {
const rheader_t *resp;
asyncns_query_t *q;
assert(asyncns);
resp = &packet->rheader;
assert(resp);
assert(length >= sizeof(rheader_t));
assert(length == resp->length);
if (resp->type == RESPONSE_DIED) {
asyncns->dead = 1;
return 0;
}
q = lookup_query(asyncns, resp->id);
if (!q)
return 0;
switch (resp->type) {
case RESPONSE_ADDRINFO: {
const addrinfo_response_t *ai_resp = &packet->addrinfo_response;
const void *p;
size_t l;
struct addrinfo *prev = NULL;
assert(length >= sizeof(addrinfo_response_t));
assert(q->type == REQUEST_ADDRINFO);
q->ret = ai_resp->ret;
q->_errno = ai_resp->_errno;
q->_h_errno = ai_resp->_h_errno;
l = length - sizeof(addrinfo_response_t);
p = (const uint8_t*) resp + sizeof(addrinfo_response_t);
while (l > 0 && p) {
struct addrinfo *ai = NULL;
p = unserialize_addrinfo(p, &ai, &l);
if (!p || !ai) {
q->ret = EAI_MEMORY;
break;
}
if (prev)
prev->ai_next = ai;
else
q->addrinfo = ai;
prev = ai;
}
complete_query(asyncns, q);
break;
}
case RESPONSE_NAMEINFO: {
const nameinfo_response_t *ni_resp = &packet->nameinfo_response;
assert(length >= sizeof(nameinfo_response_t));
assert(q->type == REQUEST_NAMEINFO);
q->ret = ni_resp->ret;
q->_errno = ni_resp->_errno;
q->_h_errno = ni_resp->_h_errno;
if (ni_resp->hostlen)
if (!(q->host = strndup((const char*) ni_resp + sizeof(nameinfo_response_t), ni_resp->hostlen-1)))
q->ret = EAI_MEMORY;
if (ni_resp->servlen)
if (!(q->serv = strndup((const char*) ni_resp + sizeof(nameinfo_response_t) + ni_resp->hostlen, ni_resp->servlen-1)))
q->ret = EAI_MEMORY;
complete_query(asyncns, q);
break;
}
case RESPONSE_RES: {
const res_response_t *res_resp = &packet->res_response;
assert(length >= sizeof(res_response_t));
assert(q->type == REQUEST_RES_QUERY || q->type == REQUEST_RES_SEARCH);
q->ret = res_resp->ret;
q->_errno = res_resp->_errno;
q->_h_errno = res_resp->_h_errno;
if (res_resp->ret >= 0) {
if (!(q->serv = malloc(res_resp->ret))) {
q->ret = -1;
q->_errno = ENOMEM;
} else
memcpy(q->serv, (const char *)resp + sizeof(res_response_t), res_resp->ret);
}
complete_query(asyncns, q);
break;
}
default:
;
}
return 0;
}
int asyncns_wait(asyncns_t *asyncns, int block) {
int handled = 0;
assert(asyncns);
for (;;) {
packet_t buf[BUFSIZE/sizeof(packet_t) + 1];
ssize_t l;
if (asyncns->dead) {
errno = ECHILD;
return -1;
}
l = recv(asyncns->fds[RESPONSE_RECV_FD], buf, sizeof(buf), 0);
if (l < 0) {
fd_set fds;
if (errno != EAGAIN)
return -1;
if (!block || handled)
return 0;
FD_ZERO(&fds);
FD_SET(asyncns->fds[RESPONSE_RECV_FD], &fds);
if (select(asyncns->fds[RESPONSE_RECV_FD]+1, &fds, NULL, NULL, NULL) < 0)
return -1;
continue;
}
if (handle_response(asyncns, buf, (size_t) l) < 0)
return -1;
handled = 1;
}
}
static asyncns_query_t *alloc_query(asyncns_t *asyncns) {
asyncns_query_t *q;
assert(asyncns);
if (asyncns->n_queries >= MAX_QUERIES) {
errno = ENOMEM;
return NULL;
}
while (asyncns->queries[asyncns->current_index]) {
asyncns->current_index++;
asyncns->current_id++;
while (asyncns->current_index >= MAX_QUERIES)
asyncns->current_index -= MAX_QUERIES;
}
q = asyncns->queries[asyncns->current_index] = malloc(sizeof(asyncns_query_t));
if (!q) {
errno = ENOMEM;
return NULL;
}
asyncns->n_queries++;
q->asyncns = asyncns;
q->done = 0;
q->id = asyncns->current_id;
q->done_next = q->done_prev = NULL;
q->ret = 0;
q->_errno = 0;
q->_h_errno = 0;
q->addrinfo = NULL;
q->userdata = NULL;
q->host = q->serv = NULL;
return q;
}
asyncns_query_t* asyncns_getaddrinfo(asyncns_t *asyncns, const char *node, const char *service, const struct addrinfo *hints) {
addrinfo_request_t data[BUFSIZE/sizeof(addrinfo_request_t) + 1] = {};
addrinfo_request_t *req = data;
asyncns_query_t *q;
assert(asyncns);
assert(node || service);
if (asyncns->dead) {
errno = ECHILD;
return NULL;
}
q = alloc_query(asyncns);
if (!q)
return NULL;
req->node_len = node ? strlen(node)+1 : 0;
req->service_len = service ? strlen(service)+1 : 0;
req->header.id = q->id;
req->header.type = q->type = REQUEST_ADDRINFO;
req->header.length = sizeof(addrinfo_request_t) + req->node_len + req->service_len;
if (req->header.length > BUFSIZE) {
errno = ENOMEM;
goto fail;
}
if (!(req->hints_is_null = !hints)) {
req->ai_flags = hints->ai_flags;
req->ai_family = hints->ai_family;
req->ai_socktype = hints->ai_socktype;
req->ai_protocol = hints->ai_protocol;
}
if (node)
strcpy((char*) req + sizeof(addrinfo_request_t), node);
if (service)
strcpy((char*) req + sizeof(addrinfo_request_t) + req->node_len, service);
if (send(asyncns->fds[REQUEST_SEND_FD], req, req->header.length, MSG_NOSIGNAL) < 0)
goto fail;
return q;
fail:
if (q)
asyncns_cancel(asyncns, q);
return NULL;
}
int asyncns_getaddrinfo_done(asyncns_t *asyncns, asyncns_query_t* q, struct addrinfo **ret_res) {
int ret;
assert(asyncns);
assert(q);
assert(q->asyncns == asyncns);
assert(q->type == REQUEST_ADDRINFO);
if (asyncns->dead) {
errno = ECHILD;
return EAI_SYSTEM;
}
if (!q->done)
return EAI_AGAIN;
*ret_res = q->addrinfo;
q->addrinfo = NULL;
ret = q->ret;
if (ret == EAI_SYSTEM)
errno = q->_errno;
if (ret != 0)
h_errno = q->_h_errno;
asyncns_cancel(asyncns, q);
return ret;
}
asyncns_query_t* asyncns_getnameinfo(asyncns_t *asyncns, const struct sockaddr *sa, socklen_t salen, int flags, int gethost, int getserv) {
nameinfo_request_t data[BUFSIZE/sizeof(nameinfo_request_t) + 1] = {};
nameinfo_request_t *req = data;
asyncns_query_t *q;
assert(asyncns);
assert(sa);
assert(salen > 0);
if (asyncns->dead) {
errno = ECHILD;
return NULL;
}
q = alloc_query(asyncns);
if (!q)
return NULL;
req->header.id = q->id;
req->header.type = q->type = REQUEST_NAMEINFO;
req->header.length = sizeof(nameinfo_request_t) + salen;
if (req->header.length > BUFSIZE) {
errno = ENOMEM;
goto fail;
}
req->flags = flags;
req->sockaddr_len = salen;
req->gethost = gethost;
req->getserv = getserv;
memcpy((uint8_t*) req + sizeof(nameinfo_request_t), sa, salen);
if (send(asyncns->fds[REQUEST_SEND_FD], req, req->header.length, MSG_NOSIGNAL) < 0)
goto fail;
return q;
fail:
if (q)
asyncns_cancel(asyncns, q);
return NULL;
}
int asyncns_getnameinfo_done(asyncns_t *asyncns, asyncns_query_t* q, char *ret_host, size_t hostlen, char *ret_serv, size_t servlen) {
int ret;
assert(asyncns);
assert(q);
assert(q->asyncns == asyncns);
assert(q->type == REQUEST_NAMEINFO);
assert(!ret_host || hostlen);
assert(!ret_serv || servlen);
if (asyncns->dead) {
errno = ECHILD;
return EAI_SYSTEM;
}
if (!q->done)
return EAI_AGAIN;
if (ret_host && q->host) {
strncpy(ret_host, q->host, hostlen);
ret_host[hostlen-1] = 0;
}
if (ret_serv && q->serv) {
strncpy(ret_serv, q->serv, servlen);
ret_serv[servlen-1] = 0;
}
ret = q->ret;
if (ret == EAI_SYSTEM)
errno = q->_errno;
if (ret != 0)
h_errno = q->_h_errno;
asyncns_cancel(asyncns, q);
return ret;
}
static asyncns_query_t * asyncns_res(asyncns_t *asyncns, query_type_t qtype, const char *dname, int class, int type) {
res_request_t data[BUFSIZE/sizeof(res_request_t) + 1];
res_request_t *req = data;
asyncns_query_t *q;
assert(asyncns);
assert(dname);
if (asyncns->dead) {
errno = ECHILD;
return NULL;
}
q = alloc_query(asyncns);
if (!q)
return NULL;
req->dname_len = strlen(dname) + 1;
req->header.id = q->id;
req->header.type = q->type = qtype;
req->header.length = sizeof(res_request_t) + req->dname_len;
if (req->header.length > BUFSIZE) {
errno = ENOMEM;
goto fail;
}
req->class = class;
req->type = type;
strcpy((char*) req + sizeof(res_request_t), dname);
if (send(asyncns->fds[REQUEST_SEND_FD], req, req->header.length, MSG_NOSIGNAL) < 0)
goto fail;
return q;
fail:
if (q)
asyncns_cancel(asyncns, q);
return NULL;
}
asyncns_query_t* asyncns_res_query(asyncns_t *asyncns, const char *dname, int class, int type) {
return asyncns_res(asyncns, REQUEST_RES_QUERY, dname, class, type);
}
asyncns_query_t* asyncns_res_search(asyncns_t *asyncns, const char *dname, int class, int type) {
return asyncns_res(asyncns, REQUEST_RES_SEARCH, dname, class, type);
}
int asyncns_res_done(asyncns_t *asyncns, asyncns_query_t* q, unsigned char **answer) {
int ret;
assert(asyncns);
assert(q);
assert(q->asyncns == asyncns);
assert(q->type == REQUEST_RES_QUERY || q->type == REQUEST_RES_SEARCH);
assert(answer);
if (asyncns->dead) {
errno = ECHILD;
return -ECHILD;
}
if (!q->done) {
errno = EAGAIN;
return -EAGAIN;
}
*answer = (unsigned char *)q->serv;
q->serv = NULL;
ret = q->ret;
if (ret < 0) {
errno = q->_errno;
h_errno = q->_h_errno;
}
asyncns_cancel(asyncns, q);
return ret < 0 ? -errno : ret;
}
asyncns_query_t* asyncns_getnext(asyncns_t *asyncns) {
assert(asyncns);
return asyncns->done_head;
}
int asyncns_getnqueries(asyncns_t *asyncns) {
assert(asyncns);
return asyncns->n_queries;
}
void asyncns_cancel(asyncns_t *asyncns, asyncns_query_t* q) {
int i;
int saved_errno = errno;
assert(asyncns);
assert(q);
assert(q->asyncns == asyncns);
assert(asyncns->n_queries > 0);
if (q->done) {
if (q->done_prev)
q->done_prev->done_next = q->done_next;
else
asyncns->done_head = q->done_next;
if (q->done_next)
q->done_next->done_prev = q->done_prev;
else
asyncns->done_tail = q->done_prev;
}
i = q->id % MAX_QUERIES;
assert(asyncns->queries[i] == q);
asyncns->queries[i] = NULL;
asyncns_freeaddrinfo(q->addrinfo);
free(q->host);
free(q->serv);
asyncns->n_queries--;
free(q);
errno = saved_errno;
}
void asyncns_freeaddrinfo(struct addrinfo *ai) {
int saved_errno = errno;
while (ai) {
struct addrinfo *next = ai->ai_next;
free(ai->ai_addr);
free(ai->ai_canonname);
free(ai);
ai = next;
}
errno = saved_errno;
}
void asyncns_freeanswer(unsigned char *answer) {
int saved_errno = errno;
if (!answer)
return;
/* Please note that this function is new in libasyncns 0.4. In
* older versions you were supposed to free the answer directly
* with free(). Hence, if this function is changed to do more than
* just a simple free() this must be considered ABI/API breakage! */
free(answer);
errno = saved_errno;
}
int asyncns_isdone(asyncns_t *asyncns, asyncns_query_t*q) {
assert(asyncns);
assert(q);
assert(q->asyncns == asyncns);
return q->done;
}
void asyncns_setuserdata(asyncns_t *asyncns, asyncns_query_t *q, void *userdata) {
assert(q);
assert(asyncns);
assert(q->asyncns = asyncns);
q->userdata = userdata;
}
void* asyncns_getuserdata(asyncns_t *asyncns, asyncns_query_t *q) {
assert(q);
assert(asyncns);
assert(q->asyncns = asyncns);
return q->userdata;
}
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