void ares_query(ares_channel channel, const char *name, int dnsclass,
int type, ares_callback callback, void *arg)
{
struct qquery *qquery;
unsigned char *qbuf;
int qlen, rd, status;
/* Compose the query. */
rd = !(channel->flags & ARES_FLAG_NORECURSE);
status = ares_create_query(name, dnsclass, type, channel->next_id, rd, &qbuf,
&qlen, (channel->flags & ARES_FLAG_EDNS) ? channel->ednspsz : 0);
if (status != ARES_SUCCESS)
{
if (qbuf != NULL) ares_free(qbuf);
callback(arg, status, 0, NULL, 0);
return;
}
channel->next_id = generate_unique_id(channel);
/* Allocate and fill in the query structure. */
qquery = ares_malloc(sizeof(struct qquery));
if (!qquery)
{
ares_free_string(qbuf);
callback(arg, ARES_ENOMEM, 0, NULL, 0);
return;
}
qquery->callback = callback;
qquery->arg = arg;
/* Send it off. qcallback will be called when we get an answer. */
ares_send(channel, qbuf, qlen, qcallback, qquery);
ares_free_string(qbuf);
}
/* Simply decodes a length-encoded character string. The first byte of the
* input is the length of the string to be returned and the bytes thereafter
* are the characters of the string. The returned result will be NULL
* terminated.
*/
int ares_expand_string(const unsigned char *encoded,
const unsigned char *abuf,
int alen,
unsigned char **s,
long *enclen)
{
unsigned char *q;
union {
ssize_t sig;
size_t uns;
} elen;
if (encoded == abuf+alen)
return ARES_EBADSTR;
elen.uns = *encoded;
if (encoded+elen.sig+1 > abuf+alen)
return ARES_EBADSTR;
encoded++;
*s = ares_malloc(elen.uns+1);
if (*s == NULL)
return ARES_ENOMEM;
q = *s;
strncpy((char *)q, (char *)encoded, elen.uns);
q[elen.uns] = '\0';
*s = q;
*enclen = (long)(elen.sig+1);
return ARES_SUCCESS;
}
char *ares_strdup(const char *s1)
{
#ifdef HAVE_STRDUP
if (ares_malloc == malloc)
return strdup(s1);
else
#endif
{
size_t sz;
char * s2;
if(s1) {
sz = strlen(s1);
if(sz < (size_t)-1) {
sz++;
if(sz < ((size_t)-1) / sizeof(char)) {
s2 = ares_malloc(sz * sizeof(char));
if(s2) {
memcpy(s2, s1, sz * sizeof(char));
return s2;
}
}
}
}
return (char *)NULL;
}
}
int ares_set_servers_ports(ares_channel channel,
struct ares_addr_port_node *servers)
{
struct ares_addr_port_node *srvr;
int num_srvrs = 0;
int i;
if (ares_library_initialized() != ARES_SUCCESS)
return ARES_ENOTINITIALIZED; /* LCOV_EXCL_LINE: n/a on non-WinSock */
if (!channel)
return ARES_ENODATA;
if (!ares__is_list_empty(&channel->all_queries))
return ARES_ENOTIMP;
ares__destroy_servers_state(channel);
for (srvr = servers; srvr; srvr = srvr->next)
{
num_srvrs++;
}
if (num_srvrs > 0)
{
/* Allocate storage for servers state */
channel->servers = ares_malloc(num_srvrs * sizeof(struct server_state));
if (!channel->servers)
{
return ARES_ENOMEM;
}
channel->nservers = num_srvrs;
/* Fill servers state address data */
for (i = 0, srvr = servers; srvr; i++, srvr = srvr->next)
{
channel->servers[i].addr.family = srvr->family;
channel->servers[i].addr.udp_port = htons((unsigned short)srvr->udp_port);
channel->servers[i].addr.tcp_port = htons((unsigned short)srvr->tcp_port);
if (srvr->family == AF_INET)
memcpy(&channel->servers[i].addr.addrV4, &srvr->addrV4,
sizeof(srvr->addrV4));
else
memcpy(&channel->servers[i].addr.addrV6, &srvr->addrV6,
sizeof(srvr->addrV6));
}
/* Initialize servers state remaining data */
ares__init_servers_state(channel);
}
return ARES_SUCCESS;
}
ares_ssize_t ares_writev(ares_socket_t s, const struct iovec *iov, int iovcnt)
{
char *buffer, *bp;
int i;
size_t bytes = 0;
ares_ssize_t result;
/* Validate iovcnt */
if (iovcnt <= 0)
{
SET_ERRNO(EINVAL);
return (-1);
}
/* Validate and find the sum of the iov_len values in the iov array */
for (i = 0; i < iovcnt; i++)
{
if (iov[i].iov_len > INT_MAX - bytes)
{
SET_ERRNO(EINVAL);
return (-1);
}
bytes += iov[i].iov_len;
}
if (bytes == 0)
return (0);
/* Allocate a temporary buffer to hold the data */
buffer = ares_malloc(bytes);
if (!buffer)
{
SET_ERRNO(ENOMEM);
return (-1);
}
/* Copy the data into buffer */
for (bp = buffer, i = 0; i < iovcnt; ++i)
{
memcpy (bp, iov[i].iov_base, iov[i].iov_len);
bp += iov[i].iov_len;
}
/* Send buffer contents */
result = swrite(s, buffer, bytes);
ares_free(buffer);
return (result);
}
/* Concatenate two domains. */
static int cat_domain(const char *name, const char *domain, char **s)
{
size_t nlen = strlen(name);
size_t dlen = strlen(domain);
*s = ares_malloc(nlen + 1 + dlen + 1);
if (!*s)
return ARES_ENOMEM;
memcpy(*s, name, nlen);
(*s)[nlen] = '.';
memcpy(*s + nlen + 1, domain, dlen);
(*s)[nlen + 1 + dlen] = 0;
return ARES_SUCCESS;
}
void ares_gethostbyname(ares_channel channel, const char *name, int family,
ares_host_callback callback, void *arg)
{
struct host_query *hquery;
/* Right now we only know how to look up Internet addresses - and unspec
means try both basically. */
switch (family) {
case AF_INET:
case AF_INET6:
case AF_UNSPEC:
break;
default:
callback(arg, ARES_ENOTIMP, 0, NULL);
return;
}
if (fake_hostent(name, family, callback, arg))
return;
/* Allocate and fill in the host query structure. */
hquery = ares_malloc(sizeof(struct host_query));
if (!hquery)
{
callback(arg, ARES_ENOMEM, 0, NULL);
return;
}
hquery->channel = channel;
hquery->name = ares_strdup(name);
hquery->want_family = family;
hquery->sent_family = -1; /* nothing is sent yet */
if (!hquery->name) {
ares_free(hquery);
callback(arg, ARES_ENOMEM, 0, NULL);
return;
}
hquery->callback = callback;
hquery->arg = arg;
hquery->remaining_lookups = channel->lookups;
hquery->timeouts = 0;
/* Start performing lookups according to channel->lookups. */
next_lookup(hquery, ARES_ECONNREFUSED /* initial error code */);
}
/* IPv6 addresses with ports require square brackets [fe80::1%lo0]:53 */
static int set_servers_csv(ares_channel channel,
const char* _csv, int use_port)
{
size_t i;
char* csv = NULL;
char* ptr;
char* start_host;
int cc = 0;
int rv = ARES_SUCCESS;
struct ares_addr_port_node *servers = NULL;
struct ares_addr_port_node *last = NULL;
if (ares_library_initialized() != ARES_SUCCESS)
return ARES_ENOTINITIALIZED; /* LCOV_EXCL_LINE: n/a on non-WinSock */
if (!channel)
return ARES_ENODATA;
ares__destroy_servers_state(channel);
i = strlen(_csv);
if (i == 0)
return ARES_SUCCESS; /* blank all servers */
csv = ares_malloc(i + 2);
if (!csv)
return ARES_ENOMEM;
strcpy(csv, _csv);
if (csv[i-1] != ',') { /* make parsing easier by ensuring ending ',' */
csv[i] = ',';
csv[i+1] = 0;
}
start_host = csv;
for (ptr = csv; *ptr; ptr++) {
if (*ptr == ':') {
/* count colons to determine if we have an IPv6 number or IPv4 with
port */
cc++;
}
else if (*ptr == '[') {
/* move start_host if an open square bracket is found wrapping an IPv6
address */
start_host = ptr + 1;
}
else if (*ptr == ',') {
char* pp = ptr - 1;
char* p = ptr;
int port = 0;
struct in_addr in4;
struct ares_in6_addr in6;
struct ares_addr_port_node *s = NULL;
*ptr = 0; /* null terminate host:port string */
/* Got an entry..see if the port was specified. */
if (cc > 0) {
while (pp > start_host) {
/* a single close square bracket followed by a colon, ']:' indicates
an IPv6 address with port */
if ((*pp == ']') && (*p == ':'))
break; /* found port */
/* a single colon, ':' indicates an IPv4 address with port */
if ((*pp == ':') && (cc == 1))
break; /* found port */
if (!(ISDIGIT(*pp) || (*pp == ':'))) {
/* Found end of digits before we found :, so wasn't a port */
/* must allow ':' for IPv6 case of ']:' indicates we found a port */
pp = p = ptr;
break;
}
pp--;
p--;
}
if ((pp != start_host) && ((pp + 1) < ptr)) {
/* Found it. Parse over the port number */
/* when an IPv6 address is wrapped with square brackets the port
starts at pp + 2 */
if (*pp == ']')
p++; /* move p before ':' */
/* p will point to the start of the port */
port = (int)strtol(p, NULL, 10);
*pp = 0; /* null terminate host */
}
}
/* resolve host, try ipv4 first, rslt is in network byte order */
rv = ares_inet_pton(AF_INET, start_host, &in4);
if (!rv) {
/* Ok, try IPv6 then */
rv = ares_inet_pton(AF_INET6, start_host, &in6);
if (!rv) {
rv = ARES_EBADSTR;
goto out;
}
/* was ipv6, add new server */
s = ares_malloc(sizeof(*s));
if (!s) {
rv = ARES_ENOMEM;
goto out;
}
s->family = AF_INET6;
memcpy(&s->addr, &in6, sizeof(struct ares_in6_addr));
}
else {
/* was ipv4, add new server */
s = ares_malloc(sizeof(*s));
if (!s) {
rv = ARES_ENOMEM;
goto out;
}
s->family = AF_INET;
memcpy(&s->addr, &in4, sizeof(struct in_addr));
}
if (s) {
s->udp_port = use_port ? port: 0;
s->tcp_port = s->udp_port;
s->next = NULL;
if (last) {
last->next = s;
/* need to move last to maintain the linked list */
last = last->next;
}
else {
servers = s;
last = s;
}
}
/* Set up for next one */
start_host = ptr + 1;
cc = 0;
}
}
rv = ares_set_servers_ports(channel, servers);
out:
if (csv)
ares_free(csv);
while (servers) {
struct ares_addr_port_node *s = servers;
servers = servers->next;
ares_free(s);
}
return rv;
}
int ares__get_hostent(FILE *fp, int family, struct hostent **host)
{
char *line = NULL, *p, *q, **alias;
char *txtaddr, *txthost, *txtalias;
int status;
size_t addrlen, linesize, naliases;
struct ares_addr addr;
struct hostent *hostent = NULL;
*host = NULL; /* Assume failure */
/* Validate family */
switch (family) {
case AF_INET:
case AF_INET6:
case AF_UNSPEC:
break;
default:
return ARES_EBADFAMILY;
}
while ((status = ares__read_line(fp, &line, &linesize)) == ARES_SUCCESS)
{
/* Trim line comment. */
p = line;
while (*p && (*p != '#'))
p++;
*p = '\0';
/* Trim trailing whitespace. */
q = p - 1;
while ((q >= line) && ISSPACE(*q))
q--;
*++q = '\0';
/* Skip leading whitespace. */
p = line;
while (*p && ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if empty. */
continue;
/* Pointer to start of IPv4 or IPv6 address part. */
txtaddr = p;
/* Advance past address part. */
while (*p && !ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if reached end of line. */
continue;
/* Null terminate address part. */
*p = '\0';
/* Advance to host name */
p++;
while (*p && ISSPACE(*p))
p++;
if (!*p)
/* Ignore line if reached end of line. */
continue; /* LCOV_EXCL_LINE: trailing whitespace already stripped */
/* Pointer to start of host name. */
txthost = p;
/* Advance past host name. */
while (*p && !ISSPACE(*p))
p++;
/* Pointer to start of first alias. */
txtalias = NULL;
if (*p)
{
q = p + 1;
while (*q && ISSPACE(*q))
q++;
if (*q)
txtalias = q;
}
/* Null terminate host name. */
*p = '\0';
/* find out number of aliases. */
naliases = 0;
if (txtalias)
{
p = txtalias;
while (*p)
{
while (*p && !ISSPACE(*p))
p++;
while (*p && ISSPACE(*p))
p++;
naliases++;
}
}
/* Convert address string to network address for the requested family. */
addrlen = 0;
addr.family = AF_UNSPEC;
addr.addrV4.s_addr = INADDR_NONE;
if ((family == AF_INET) || (family == AF_UNSPEC))
{
addr.addrV4.s_addr = inet_addr(txtaddr);
if (addr.addrV4.s_addr != INADDR_NONE)
{
/* Actual network address family and length. */
addr.family = AF_INET;
addrlen = sizeof(addr.addrV4);
}
}
if ((family == AF_INET6) || ((family == AF_UNSPEC) && (!addrlen)))
{
if (ares_inet_pton(AF_INET6, txtaddr, &addr.addrV6) > 0)
{
/* Actual network address family and length. */
addr.family = AF_INET6;
addrlen = sizeof(addr.addrV6);
}
}
if (!addrlen)
/* Ignore line if invalid address string for the requested family. */
continue;
/*
** Actual address family possible values are AF_INET and AF_INET6 only.
*/
/* Allocate memory for the hostent structure. */
hostent = ares_malloc(sizeof(struct hostent));
if (!hostent)
break;
/* Initialize fields for out of memory condition. */
hostent->h_aliases = NULL;
hostent->h_addr_list = NULL;
/* Copy official host name. */
hostent->h_name = ares_strdup(txthost);
if (!hostent->h_name)
break;
/* Copy network address. */
hostent->h_addr_list = ares_malloc(2 * sizeof(char *));
if (!hostent->h_addr_list)
break;
hostent->h_addr_list[1] = NULL;
hostent->h_addr_list[0] = ares_malloc(addrlen);
if (!hostent->h_addr_list[0])
break;
if (addr.family == AF_INET)
memcpy(hostent->h_addr_list[0], &addr.addrV4, sizeof(addr.addrV4));
else
memcpy(hostent->h_addr_list[0], &addr.addrV6, sizeof(addr.addrV6));
/* Copy aliases. */
hostent->h_aliases = ares_malloc((naliases + 1) * sizeof(char *));
if (!hostent->h_aliases)
break;
alias = hostent->h_aliases;
while (naliases)
*(alias + naliases--) = NULL;
*alias = NULL;
while (txtalias)
{
p = txtalias;
while (*p && !ISSPACE(*p))
p++;
q = p;
while (*q && ISSPACE(*q))
q++;
*p = '\0';
if ((*alias = ares_strdup(txtalias)) == NULL)
break;
alias++;
txtalias = *q ? q : NULL;
}
if (txtalias)
/* Alias memory allocation failure. */
break;
/* Copy actual network address family and length. */
hostent->h_addrtype = aresx_sitoss(addr.family);
hostent->h_length = aresx_uztoss(addrlen);
/* Free line buffer. */
ares_free(line);
/* Return hostent successfully */
*host = hostent;
return ARES_SUCCESS;
}
/* If allocated, free line buffer. */
if (line)
ares_free(line);
if (status == ARES_SUCCESS)
{
/* Memory allocation failure; clean up. */
if (hostent)
{
if (hostent->h_name)
ares_free((char *) hostent->h_name);
if (hostent->h_aliases)
{
for (alias = hostent->h_aliases; *alias; alias++)
ares_free(*alias);
ares_free(hostent->h_aliases);
}
if (hostent->h_addr_list)
{
if (hostent->h_addr_list[0])
ares_free(hostent->h_addr_list[0]);
ares_free(hostent->h_addr_list);
}
ares_free(hostent);
}
return ARES_ENOMEM;
}
return status;
}
int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
int addrlen, int family, struct hostent **host)
{
unsigned int qdcount, ancount;
int status, i, rr_type, rr_class, rr_len;
long len;
const unsigned char *aptr;
char *ptrname, *hostname, *rr_name, *rr_data;
struct hostent *hostent;
int aliascnt = 0;
int alias_alloc = 8;
char ** aliases;
/* Set *host to NULL for all failure cases. */
*host = NULL;
/* Give up if abuf doesn't have room for a header. */
if (alen < HFIXEDSZ)
return ARES_EBADRESP;
/* Fetch the question and answer count from the header. */
qdcount = DNS_HEADER_QDCOUNT(abuf);
ancount = DNS_HEADER_ANCOUNT(abuf);
if (qdcount != 1)
return ARES_EBADRESP;
/* Expand the name from the question, and skip past the question. */
aptr = abuf + HFIXEDSZ;
status = ares__expand_name_for_response(aptr, abuf, alen, &ptrname, &len);
if (status != ARES_SUCCESS)
return status;
if (aptr + len + QFIXEDSZ > abuf + alen)
{
ares_free(ptrname);
return ARES_EBADRESP;
}
aptr += len + QFIXEDSZ;
/* Examine each answer resource record (RR) in turn. */
hostname = NULL;
aliases = ares_malloc(alias_alloc * sizeof(char *));
if (!aliases)
{
ares_free(ptrname);
return ARES_ENOMEM;
}
for (i = 0; i < (int)ancount; i++)
{
/* Decode the RR up to the data field. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
if (status != ARES_SUCCESS)
break;
aptr += len;
if (aptr + RRFIXEDSZ > abuf + alen)
{
ares_free(rr_name);
status = ARES_EBADRESP;
break;
}
rr_type = DNS_RR_TYPE(aptr);
rr_class = DNS_RR_CLASS(aptr);
rr_len = DNS_RR_LEN(aptr);
aptr += RRFIXEDSZ;
if (aptr + rr_len > abuf + alen)
{
ares_free(rr_name);
status = ARES_EBADRESP;
break;
}
if (rr_class == C_IN && rr_type == T_PTR
&& strcasecmp(rr_name, ptrname) == 0)
{
/* Decode the RR data and set hostname to it. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_data,
&len);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
break;
}
if (hostname)
ares_free(hostname);
hostname = rr_data;
aliases[aliascnt] = ares_malloc((strlen(rr_data)+1) * sizeof(char));
if (!aliases[aliascnt])
{
ares_free(rr_name);
status = ARES_ENOMEM;
break;
}
strncpy(aliases[aliascnt], rr_data, strlen(rr_data)+1);
aliascnt++;
if (aliascnt >= alias_alloc) {
char **ptr;
alias_alloc *= 2;
ptr = ares_realloc(aliases, alias_alloc * sizeof(char *));
if(!ptr) {
ares_free(rr_name);
status = ARES_ENOMEM;
break;
}
aliases = ptr;
}
}
if (rr_class == C_IN && rr_type == T_CNAME)
{
/* Decode the RR data and replace ptrname with it. */
status = ares__expand_name_for_response(aptr, abuf, alen, &rr_data,
&len);
if (status != ARES_SUCCESS)
{
ares_free(rr_name);
break;
}
ares_free(ptrname);
ptrname = rr_data;
}
ares_free(rr_name);
aptr += rr_len;
if (aptr > abuf + alen)
{ /* LCOV_EXCL_START: already checked above */
status = ARES_EBADRESP;
break;
} /* LCOV_EXCL_STOP */
}
if (status == ARES_SUCCESS && !hostname)
status = ARES_ENODATA;
if (status == ARES_SUCCESS)
{
/* We got our answer. Allocate memory to build the host entry. */
hostent = ares_malloc(sizeof(struct hostent));
if (hostent)
{
hostent->h_addr_list = ares_malloc(2 * sizeof(char *));
if (hostent->h_addr_list)
{
hostent->h_addr_list[0] = ares_malloc(addrlen);
if (hostent->h_addr_list[0])
{
hostent->h_aliases = ares_malloc((aliascnt+1) * sizeof (char *));
if (hostent->h_aliases)
{
/* Fill in the hostent and return successfully. */
hostent->h_name = hostname;
for (i=0 ; i<aliascnt ; i++)
hostent->h_aliases[i] = aliases[i];
hostent->h_aliases[aliascnt] = NULL;
hostent->h_addrtype = aresx_sitoss(family);
hostent->h_length = aresx_sitoss(addrlen);
memcpy(hostent->h_addr_list[0], addr, addrlen);
hostent->h_addr_list[1] = NULL;
*host = hostent;
ares_free(aliases);
ares_free(ptrname);
return ARES_SUCCESS;
}
ares_free(hostent->h_addr_list[0]);
}
ares_free(hostent->h_addr_list);
}
ares_free(hostent);
}
status = ARES_ENOMEM;
}
for (i=0 ; i<aliascnt ; i++)
if (aliases[i])
ares_free(aliases[i]);
ares_free(aliases);
if (hostname)
ares_free(hostname);
ares_free(ptrname);
return status;
}
/* If any TCP socket selects true for reading, read some data,
* allocate a buffer if we finish reading the length word, and process
* a packet if we finish reading one.
*/
static void read_tcp_data(ares_channel channel, fd_set *read_fds,
ares_socket_t read_fd, struct timeval *now)
{
struct server_state *server;
int i;
ares_ssize_t count;
if(!read_fds && (read_fd == ARES_SOCKET_BAD))
/* no possible action */
return;
for (i = 0; i < channel->nservers; i++)
{
/* Make sure the server has a socket and is selected in read_fds. */
server = &channel->servers[i];
if (server->tcp_socket == ARES_SOCKET_BAD || server->is_broken)
continue;
if(read_fds) {
if(!(FD_ISSET(server->tcp_socket, read_fds)))
continue;
}
else {
if(server->tcp_socket != read_fd)
continue;
}
if(read_fds)
/* If there's an error and we close this socket, then open another
* with the same fd to talk to another server, then we don't want to
* think that it was the new socket that was ready. This is not
* disastrous, but is likely to result in extra system calls and
* confusion. */
FD_CLR(server->tcp_socket, read_fds);
if (server->tcp_lenbuf_pos != 2)
{
/* We haven't yet read a length word, so read that (or
* what's left to read of it).
*/
count = socket_recv(channel, server->tcp_socket,
server->tcp_lenbuf + server->tcp_lenbuf_pos,
2 - server->tcp_lenbuf_pos);
if (count <= 0)
{
if (!(count == -1 && try_again(SOCKERRNO)))
handle_error(channel, i, now);
continue;
}
server->tcp_lenbuf_pos += (int)count;
if (server->tcp_lenbuf_pos == 2)
{
/* We finished reading the length word. Decode the
* length and allocate a buffer for the data.
*/
server->tcp_length = server->tcp_lenbuf[0] << 8
| server->tcp_lenbuf[1];
server->tcp_buffer = ares_malloc(server->tcp_length);
if (!server->tcp_buffer) {
handle_error(channel, i, now);
return; /* bail out on malloc failure. TODO: make this
function return error codes */
}
server->tcp_buffer_pos = 0;
}
}
else
{
/* Read data into the allocated buffer. */
count = socket_recv(channel, server->tcp_socket,
server->tcp_buffer + server->tcp_buffer_pos,
server->tcp_length - server->tcp_buffer_pos);
if (count <= 0)
{
if (!(count == -1 && try_again(SOCKERRNO)))
handle_error(channel, i, now);
continue;
}
server->tcp_buffer_pos += (int)count;
if (server->tcp_buffer_pos == server->tcp_length)
{
/* We finished reading this answer; process it and
* prepare to read another length word.
*/
process_answer(channel, server->tcp_buffer, server->tcp_length,
i, 1, now);
ares_free(server->tcp_buffer);
server->tcp_buffer = NULL;
server->tcp_lenbuf_pos = 0;
server->tcp_buffer_pos = 0;
}
}
}
}
/* If any TCP sockets select true for writing, write out queued data
* we have for them.
*/
static void write_tcp_data(ares_channel channel,
fd_set *write_fds,
ares_socket_t write_fd,
struct timeval *now)
{
struct server_state *server;
struct send_request *sendreq;
struct iovec *vec;
int i;
ares_ssize_t scount;
ares_ssize_t wcount;
size_t n;
if(!write_fds && (write_fd == ARES_SOCKET_BAD))
/* no possible action */
return;
for (i = 0; i < channel->nservers; i++)
{
/* Make sure server has data to send and is selected in write_fds or
write_fd. */
server = &channel->servers[i];
if (!server->qhead || server->tcp_socket == ARES_SOCKET_BAD ||
server->is_broken)
continue;
if(write_fds) {
if(!(FD_ISSET(server->tcp_socket, write_fds)))
continue;
}
else {
if(server->tcp_socket != write_fd)
continue;
}
if(write_fds)
/* If there's an error and we close this socket, then open
* another with the same fd to talk to another server, then we
* don't want to think that it was the new socket that was
* ready. This is not disastrous, but is likely to result in
* extra system calls and confusion. */
FD_CLR(server->tcp_socket, write_fds);
/* Count the number of send queue items. */
n = 0;
for (sendreq = server->qhead; sendreq; sendreq = sendreq->next)
n++;
/* Allocate iovecs so we can send all our data at once. */
vec = ares_malloc(n * sizeof(struct iovec));
if (vec)
{
/* Fill in the iovecs and send. */
n = 0;
for (sendreq = server->qhead; sendreq; sendreq = sendreq->next)
{
vec[n].iov_base = (char *) sendreq->data;
vec[n].iov_len = sendreq->len;
n++;
}
wcount = socket_writev(channel, server->tcp_socket, vec, (int)n);
ares_free(vec);
if (wcount < 0)
{
if (!try_again(SOCKERRNO))
handle_error(channel, i, now);
continue;
}
/* Advance the send queue by as many bytes as we sent. */
advance_tcp_send_queue(channel, i, wcount);
}
else
{
/* Can't allocate iovecs; just send the first request. */
sendreq = server->qhead;
scount = socket_write(channel, server->tcp_socket, sendreq->data, sendreq->len);
if (scount < 0)
{
if (!try_again(SOCKERRNO))
handle_error(channel, i, now);
continue;
}
/* Advance the send queue by as many bytes as we sent. */
advance_tcp_send_queue(channel, i, scount);
}
}
}
void ares_search(ares_channel channel, const char *name, int dnsclass,
int type, ares_callback callback, void *arg)
{
struct search_query *squery;
char *s;
const char *p;
int status, ndots;
/* If name only yields one domain to search, then we don't have
* to keep extra state, so just do an ares_query().
*/
status = single_domain(channel, name, &s);
if (status != ARES_SUCCESS)
{
callback(arg, status, 0, NULL, 0);
return;
}
if (s)
{
ares_query(channel, s, dnsclass, type, callback, arg);
ares_free(s);
return;
}
/* Allocate a search_query structure to hold the state necessary for
* doing multiple lookups.
*/
squery = ares_malloc(sizeof(struct search_query));
if (!squery)
{
callback(arg, ARES_ENOMEM, 0, NULL, 0);
return;
}
squery->channel = channel;
squery->name = ares_strdup(name);
if (!squery->name)
{
ares_free(squery);
callback(arg, ARES_ENOMEM, 0, NULL, 0);
return;
}
squery->dnsclass = dnsclass;
squery->type = type;
squery->status_as_is = -1;
squery->callback = callback;
squery->arg = arg;
squery->timeouts = 0;
squery->ever_got_nodata = 0;
/* Count the number of dots in name. */
ndots = 0;
for (p = name; *p; p++)
{
if (*p == '.')
ndots++;
}
/* If ndots is at least the channel ndots threshold (usually 1),
* then we try the name as-is first. Otherwise, we try the name
* as-is last.
*/
if (ndots >= channel->ndots)
{
/* Try the name as-is first. */
squery->next_domain = 0;
squery->trying_as_is = 1;
ares_query(channel, name, dnsclass, type, search_callback, squery);
}
else
{
/* Try the name as-is last; start with the first search domain. */
squery->next_domain = 1;
squery->trying_as_is = 0;
status = cat_domain(name, channel->domains[0], &s);
if (status == ARES_SUCCESS)
{
ares_query(channel, s, dnsclass, type, search_callback, squery);
ares_free(s);
}
else
{
/* failed, free the malloc()ed memory */
ares_free(squery->name);
ares_free(squery);
callback(arg, status, 0, NULL, 0);
}
}
}
/* Determine if this name only yields one query. If it does, set *s to
* the string we should query, in an allocated buffer. If not, set *s
* to NULL.
*/
STATIC_TESTABLE int single_domain(ares_channel channel, const char *name, char **s)
{
size_t len = strlen(name);
const char *hostaliases;
FILE *fp;
char *line = NULL;
int status;
size_t linesize;
const char *p, *q;
int error;
/* If the name contains a trailing dot, then the single query is the name
* sans the trailing dot.
*/
if ((len > 0) && (name[len - 1] == '.'))
{
*s = ares_strdup(name);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
if (!(channel->flags & ARES_FLAG_NOALIASES) && !strchr(name, '.'))
{
/* The name might be a host alias. */
hostaliases = getenv("HOSTALIASES");
if (hostaliases)
{
fp = fopen(hostaliases, "r");
if (fp)
{
while ((status = ares__read_line(fp, &line, &linesize))
== ARES_SUCCESS)
{
if (strncasecmp(line, name, len) != 0 ||
!ISSPACE(line[len]))
continue;
p = line + len;
while (ISSPACE(*p))
p++;
if (*p)
{
q = p + 1;
while (*q && !ISSPACE(*q))
q++;
*s = ares_malloc(q - p + 1);
if (*s)
{
memcpy(*s, p, q - p);
(*s)[q - p] = 0;
}
ares_free(line);
fclose(fp);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
}
ares_free(line);
fclose(fp);
if (status != ARES_SUCCESS && status != ARES_EOF)
return status;
}
else
{
error = ERRNO;
switch(error)
{
case ENOENT:
case ESRCH:
break;
default:
DEBUGF(fprintf(stderr, "fopen() failed with error: %d %s\n",
error, strerror(error)));
DEBUGF(fprintf(stderr, "Error opening file: %s\n",
hostaliases));
*s = NULL;
return ARES_EFILE;
}
}
}
}
if (channel->flags & ARES_FLAG_NOSEARCH || channel->ndomains == 0)
{
/* No domain search to do; just try the name as-is. */
*s = ares_strdup(name);
return (*s) ? ARES_SUCCESS : ARES_ENOMEM;
}
*s = NULL;
return ARES_SUCCESS;
}
