/*
* HTTP address list routines for CUPS.
*
* Copyright 2007-2016 by Apple Inc.
* Copyright 1997-2007 by Easy Software Products, all rights reserved.
*
* These coded instructions, statements, and computer programs are the
* property of Apple Inc. and are protected by Federal copyright
* law. Distribution and use rights are outlined in the file "LICENSE.txt"
* which should have been included with this file. If this file is
* missing or damaged, see the license at "http://www.cups.org/".
*
* This file is subject to the Apple OS-Developed Software exception.
*/
/*
* Include necessary headers...
*/
#include "cups-private.h"
#ifdef HAVE_RESOLV_H
# include <resolv.h>
#endif /* HAVE_RESOLV_H */
#ifdef HAVE_POLL
# include <poll.h>
#endif /* HAVE_POLL */
#ifndef WIN32
# include <fcntl.h>
#endif /* WIN32 */
/*
* 'httpAddrConnect()' - Connect to any of the addresses in the list.
*
* @since CUPS 1.2/macOS 10.5@
*/
http_addrlist_t * /* O - Connected address or NULL on failure */
httpAddrConnect(
http_addrlist_t *addrlist, /* I - List of potential addresses */
int *sock) /* O - Socket */
{
DEBUG_printf(("httpAddrConnect(addrlist=%p, sock=%p)", (void *)addrlist, (void *)sock));
return (httpAddrConnect2(addrlist, sock, 30000, NULL));
}
/*
* 'httpAddrConnect2()' - Connect to any of the addresses in the list with a
* timeout and optional cancel.
*
* @since CUPS 1.7/macOS 10.9@
*/
http_addrlist_t * /* O - Connected address or NULL on failure */
httpAddrConnect2(
http_addrlist_t *addrlist, /* I - List of potential addresses */
int *sock, /* O - Socket */
int msec, /* I - Timeout in milliseconds */
int *cancel) /* I - Pointer to "cancel" variable */
{
int val; /* Socket option value */
#ifndef WIN32
int flags; /* Socket flags */
#endif /* !WIN32 */
int remaining; /* Remaining timeout */
int i, /* Looping var */
nfds, /* Number of file descriptors */
fds[100], /* Socket file descriptors */
result; /* Result from select() or poll() */
http_addrlist_t *addrs[100]; /* Addresses */
#ifndef HAVE_POLL
int max_fd = -1; /* Highest file descriptor */
#endif /* !HAVE_POLL */
#ifdef O_NONBLOCK
# ifdef HAVE_POLL
struct pollfd pfds[100]; /* Polled file descriptors */
# else
fd_set input_set, /* select() input set */
output_set, /* select() output set */
error_set; /* select() error set */
struct timeval timeout; /* Timeout */
# endif /* HAVE_POLL */
#endif /* O_NONBLOCK */
#ifdef DEBUG
socklen_t len; /* Length of value */
http_addr_t peer; /* Peer address */
char temp[256]; /* Temporary address string */
#endif /* DEBUG */
DEBUG_printf(("httpAddrConnect2(addrlist=%p, sock=%p, msec=%d, cancel=%p)", (void *)addrlist, (void *)sock, msec, (void *)cancel));
if (!sock)
{
errno = EINVAL;
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), 0);
return (NULL);
}
if (cancel && *cancel)
return (NULL);
if (msec <= 0)
msec = INT_MAX;
/*
* Loop through each address until we connect or run out of addresses...
*/
nfds = 0;
remaining = msec;
while (remaining > 0)
{
if (cancel && *cancel)
{
while (nfds > 0)
{
nfds --;
httpAddrClose(NULL, fds[nfds]);
}
return (NULL);
}
if (addrlist && nfds < (int)(sizeof(fds) / sizeof(fds[0])))
{
/*
* Create the socket...
*/
DEBUG_printf(("2httpAddrConnect2: Trying %s:%d...", httpAddrString(&(addrlist->addr), temp, sizeof(temp)), httpAddrPort(&(addrlist->addr))));
if ((fds[nfds] = (int)socket(httpAddrFamily(&(addrlist->addr)), SOCK_STREAM, 0)) < 0)
{
/*
* Don't abort yet, as this could just be an issue with the local
* system not being configured with IPv4/IPv6/domain socket enabled.
*
* Just skip this address...
*/
addrlist = addrlist->next;
continue;
}
/*
* Set options...
*/
val = 1;
setsockopt(fds[nfds], SOL_SOCKET, SO_REUSEADDR, CUPS_SOCAST &val, sizeof(val));
#ifdef SO_REUSEPORT
val = 1;
setsockopt(fds[nfds], SOL_SOCKET, SO_REUSEPORT, CUPS_SOCAST &val, sizeof(val));
#endif /* SO_REUSEPORT */
#ifdef SO_NOSIGPIPE
val = 1;
setsockopt(fds[nfds], SOL_SOCKET, SO_NOSIGPIPE, CUPS_SOCAST &val, sizeof(val));
#endif /* SO_NOSIGPIPE */
/*
* Using TCP_NODELAY improves responsiveness, especially on systems
* with a slow loopback interface...
*/
val = 1;
setsockopt(fds[nfds], IPPROTO_TCP, TCP_NODELAY, CUPS_SOCAST &val, sizeof(val));
#ifdef FD_CLOEXEC
/*
* Close this socket when starting another process...
*/
fcntl(fds[nfds], F_SETFD, FD_CLOEXEC);
#endif /* FD_CLOEXEC */
#ifdef O_NONBLOCK
/*
* Do an asynchronous connect by setting the socket non-blocking...
*/
DEBUG_printf(("httpAddrConnect2: Setting non-blocking connect()"));
flags = fcntl(fds[nfds], F_GETFL, 0);
fcntl(fds[nfds], F_SETFL, flags | O_NONBLOCK);
#endif /* O_NONBLOCK */
/*
* Then connect...
*/
if (!connect(fds[nfds], &(addrlist->addr.addr), (socklen_t)httpAddrLength(&(addrlist->addr))))
{
DEBUG_printf(("1httpAddrConnect2: Connected to %s:%d...", httpAddrString(&(addrlist->addr), temp, sizeof(temp)), httpAddrPort(&(addrlist->addr))));
#ifdef O_NONBLOCK
fcntl(fds[nfds], F_SETFL, flags);
#endif /* O_NONBLOCK */
*sock = fds[nfds];
while (nfds > 0)
{
nfds --;
httpAddrClose(NULL, fds[nfds]);
}
return (addrlist);
}
#ifdef WIN32
if (WSAGetLastError() != WSAEINPROGRESS && WSAGetLastError() != WSAEWOULDBLOCK)
#else
if (errno != EINPROGRESS && errno != EWOULDBLOCK)
#endif /* WIN32 */
{
DEBUG_printf(("1httpAddrConnect2: Unable to connect to %s:%d: %s", httpAddrString(&(addrlist->addr), temp, sizeof(temp)), httpAddrPort(&(addrlist->addr)), strerror(errno)));
httpAddrClose(NULL, fds[nfds]);
addrlist = addrlist->next;
continue;
}
#ifndef WIN32
fcntl(fds[nfds], F_SETFL, flags);
#endif /* !WIN32 */
#ifndef HAVE_POLL
if (fds[nfds] > max_fd)
max_fd = fds[nfds];
#endif /* !HAVE_POLL */
addrs[nfds] = addrlist;
nfds ++;
addrlist = addrlist->next;
}
if (!addrlist && nfds == 0)
break;
/*
* See if we can connect to any of the addresses so far...
*/
#ifdef O_NONBLOCK
DEBUG_puts("1httpAddrConnect2: Finishing async connect()");
do
{
if (cancel && *cancel)
{
/*
* Close this socket and return...
*/
DEBUG_puts("1httpAddrConnect2: Canceled connect()");
while (nfds > 0)
{
nfds --;
httpAddrClose(NULL, fds[nfds]);
}
*sock = -1;
return (NULL);
}
# ifdef HAVE_POLL
for (i = 0; i < nfds; i ++)
{
pfds[i].fd = fds[i];
pfds[i].events = POLLIN | POLLOUT;
}
result = poll(pfds, (nfds_t)nfds, addrlist ? 100 : remaining > 250 ? 250 : remaining);
DEBUG_printf(("1httpAddrConnect2: poll() returned %d (%d)", result, errno));
# else
FD_ZERO(&input_set);
for (i = 0; i < nfds; i ++)
FD_SET(fds[i], &input_set);
output_set = input_set;
error_set = input_set;
timeout.tv_sec = 0;
timeout.tv_usec = (addrlist ? 100 : remaining > 250 ? 250 : remaining) * 1000;
result = select(max_fd + 1, &input_set, &output_set, &error_set, &timeout);
DEBUG_printf(("1httpAddrConnect2: select() returned %d (%d)", result, errno));
# endif /* HAVE_POLL */
}
# ifdef WIN32
while (result < 0 && (WSAGetLastError() == WSAEINTR || WSAGetLastError() == WSAEWOULDBLOCK));
# else
while (result < 0 && (errno == EINTR || errno == EAGAIN));
# endif /* WIN32 */
if (result > 0)
{
http_addrlist_t *connaddr = NULL; /* Connected address, if any */
for (i = 0; i < nfds; i ++)
{
# ifdef HAVE_POLL
DEBUG_printf(("pfds[%d].revents=%x\n", i, pfds[i].revents));
if (pfds[i].revents && !(pfds[i].revents & (POLLERR | POLLHUP)))
# else
if (FD_ISSET(fds[i], &input_set) && !FD_ISSET(fds[i], &error_set))
# endif /* HAVE_POLL */
{
*sock = fds[i];
connaddr = addrs[i];
# ifdef DEBUG
len = sizeof(peer);
if (!getpeername(fds[i], (struct sockaddr *)&peer, &len))
DEBUG_printf(("1httpAddrConnect2: Connected to %s:%d...", httpAddrString(&peer, temp, sizeof(temp)), httpAddrPort(&peer)));
# endif /* DEBUG */
}
# ifdef HAVE_POLL
else if (pfds[i].revents & (POLLERR | POLLHUP))
# else
else if (FD_ISSET(fds[i], &error_set))
# endif /* HAVE_POLL */
{
/*
* Error on socket, remove from the "pool"...
*/
httpAddrClose(NULL, fds[i]);
nfds --;
if (i < nfds)
{
memmove(fds + i, fds + i + 1, (size_t)(nfds - i) * (sizeof(fds[0])));
memmove(addrs + i, addrs + i + 1, (size_t)(nfds - i) * (sizeof(addrs[0])));
}
i --;
}
}
if (connaddr)
return (connaddr);
}
#endif /* O_NONBLOCK */
if (addrlist)
remaining -= 100;
else
remaining -= 250;
}
while (nfds > 0)
{
nfds --;
httpAddrClose(NULL, fds[nfds]);
}
#ifdef WIN32
_cupsSetError(IPP_STATUS_ERROR_SERVICE_UNAVAILABLE, "Connection failed", 0);
#else
_cupsSetError(IPP_STATUS_ERROR_SERVICE_UNAVAILABLE, strerror(errno), 0);
#endif /* WIN32 */
return (NULL);
}
/*
* 'httpAddrCopyList()' - Copy an address list.
*
* @since CUPS 1.7/macOS 10.9@
*/
http_addrlist_t * /* O - New address list or @code NULL@ on error */
httpAddrCopyList(
http_addrlist_t *src) /* I - Source address list */
{
http_addrlist_t *dst = NULL, /* First list entry */
*prev = NULL, /* Previous list entry */
*current = NULL;/* Current list entry */
while (src)
{
if ((current = malloc(sizeof(http_addrlist_t))) == NULL)
{
current = dst;
while (current)
{
prev = current;
current = current->next;
free(prev);
}
return (NULL);
}
memcpy(current, src, sizeof(http_addrlist_t));
current->next = NULL;
if (prev)
prev->next = current;
else
dst = current;
prev = current;
src = src->next;
}
return (dst);
}
/*
* 'httpAddrFreeList()' - Free an address list.
*
* @since CUPS 1.2/macOS 10.5@
*/
void
httpAddrFreeList(
http_addrlist_t *addrlist) /* I - Address list to free */
{
http_addrlist_t *next; /* Next address in list */
/*
* Free each address in the list...
*/
while (addrlist)
{
next = addrlist->next;
free(addrlist);
addrlist = next;
}
}
/*
* 'httpAddrGetList()' - Get a list of addresses for a hostname.
*
* @since CUPS 1.2/macOS 10.5@
*/
http_addrlist_t * /* O - List of addresses or NULL */
httpAddrGetList(const char *hostname, /* I - Hostname, IP address, or NULL for passive listen address */
int family, /* I - Address family or AF_UNSPEC */
const char *service) /* I - Service name or port number */
{
http_addrlist_t *first, /* First address in list */
*addr, /* Current address in list */
*temp; /* New address */
_cups_globals_t *cg = _cupsGlobals();
/* Global data */
#ifdef DEBUG
_cups_debug_printf("httpAddrGetList(hostname=\"%s\", family=AF_%s, "
"service=\"%s\")\n",
hostname ? hostname : "(nil)",
family == AF_UNSPEC ? "UNSPEC" :
# ifdef AF_LOCAL
family == AF_LOCAL ? "LOCAL" :
# endif /* AF_LOCAL */
# ifdef AF_INET6
family == AF_INET6 ? "INET6" :
# endif /* AF_INET6 */
family == AF_INET ? "INET" : "???", service);
#endif /* DEBUG */
#ifdef HAVE_RES_INIT
/*
* STR #2920: Initialize resolver after failure in cups-polld
*
* If the previous lookup failed, re-initialize the resolver to prevent
* temporary network errors from persisting. This *should* be handled by
* the resolver libraries, but apparently the glibc folks do not agree.
*
* We set a flag at the end of this function if we encounter an error that
* requires reinitialization of the resolver functions. We then call
* res_init() if the flag is set on the next call here or in httpAddrLookup().
*/
if (cg->need_res_init)
{
res_init();
cg->need_res_init = 0;
}
#endif /* HAVE_RES_INIT */
/*
* Lookup the address the best way we can...
*/
first = addr = NULL;
#ifdef AF_LOCAL
if (hostname && hostname[0] == '/')
{
/*
* Domain socket address...
*/
if ((first = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t))) != NULL)
{
addr = first;
first->addr.un.sun_family = AF_LOCAL;
strlcpy(first->addr.un.sun_path, hostname, sizeof(first->addr.un.sun_path));
}
}
else
#endif /* AF_LOCAL */
if (!hostname || _cups_strcasecmp(hostname, "localhost"))
{
#ifdef HAVE_GETADDRINFO
struct addrinfo hints, /* Address lookup hints */
*results, /* Address lookup results */
*current; /* Current result */
char ipv6[64], /* IPv6 address */
*ipv6zone; /* Pointer to zone separator */
int ipv6len; /* Length of IPv6 address */
int error; /* getaddrinfo() error */
/*
* Lookup the address as needed...
*/
memset(&hints, 0, sizeof(hints));
hints.ai_family = family;
hints.ai_flags = hostname ? 0 : AI_PASSIVE;
hints.ai_socktype = SOCK_STREAM;
if (hostname && *hostname == '[')
{
/*
* Remove brackets from numeric IPv6 address...
*/
if (!strncmp(hostname, "[v1.", 4))
{
/*
* Copy the newer address format which supports link-local addresses...
*/
strlcpy(ipv6, hostname + 4, sizeof(ipv6));
if ((ipv6len = (int)strlen(ipv6) - 1) >= 0 && ipv6[ipv6len] == ']')
{
ipv6[ipv6len] = '\0';
hostname = ipv6;
/*
* Convert "+zone" in address to "%zone"...
*/
if ((ipv6zone = strrchr(ipv6, '+')) != NULL)
*ipv6zone = '%';
}
}
else
{
/*
* Copy the regular non-link-local IPv6 address...
*/
strlcpy(ipv6, hostname + 1, sizeof(ipv6));
if ((ipv6len = (int)strlen(ipv6) - 1) >= 0 && ipv6[ipv6len] == ']')
{
ipv6[ipv6len] = '\0';
hostname = ipv6;
}
}
}
if ((error = getaddrinfo(hostname, service, &hints, &results)) == 0)
{
/*
* Copy the results to our own address list structure...
*/
for (current = results; current; current = current->ai_next)
if (current->ai_family == AF_INET || current->ai_family == AF_INET6)
{
/*
* Copy the address over...
*/
temp = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t));
if (!temp)
{
httpAddrFreeList(first);
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), 0);
return (NULL);
}
if (current->ai_family == AF_INET6)
memcpy(&(temp->addr.ipv6), current->ai_addr,
sizeof(temp->addr.ipv6));
else
memcpy(&(temp->addr.ipv4), current->ai_addr,
sizeof(temp->addr.ipv4));
/*
* Append the address to the list...
*/
if (!first)
first = temp;
if (addr)
addr->next = temp;
addr = temp;
}
/*
* Free the results from getaddrinfo()...
*/
freeaddrinfo(results);
}
else
{
if (error == EAI_FAIL)
cg->need_res_init = 1;
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, gai_strerror(error), 0);
}
#else
if (hostname)
{
int i; /* Looping vars */
unsigned ip[4]; /* IPv4 address components */
const char *ptr; /* Pointer into hostname */
struct hostent *host; /* Result of lookup */
struct servent *port; /* Port number for service */
int portnum; /* Port number */
/*
* Lookup the service...
*/
if (!service)
portnum = 0;
else if (isdigit(*service & 255))
portnum = atoi(service);
else if ((port = getservbyname(service, NULL)) != NULL)
portnum = ntohs(port->s_port);
else if (!strcmp(service, "http"))
portnum = 80;
else if (!strcmp(service, "https"))
portnum = 443;
else if (!strcmp(service, "ipp") || !strcmp(service, "ipps"))
portnum = 631;
else if (!strcmp(service, "lpd"))
portnum = 515;
else if (!strcmp(service, "socket"))
portnum = 9100;
else
return (NULL);
/*
* This code is needed because some operating systems have a
* buggy implementation of gethostbyname() that does not support
* IPv4 addresses. If the hostname string is an IPv4 address, then
* sscanf() is used to extract the IPv4 components. We then pack
* the components into an IPv4 address manually, since the
* inet_aton() function is deprecated. We use the htonl() macro
* to get the right byte order for the address.
*/
for (ptr = hostname; isdigit(*ptr & 255) || *ptr == '.'; ptr ++);
if (!*ptr)
{
/*
* We have an IPv4 address; break it up and create an IPv4 address...
*/
if (sscanf(hostname, "%u.%u.%u.%u", ip, ip + 1, ip + 2, ip + 3) == 4 &&
ip[0] <= 255 && ip[1] <= 255 && ip[2] <= 255 && ip[3] <= 255)
{
first = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t));
if (!first)
return (NULL);
first->addr.ipv4.sin_family = AF_INET;
first->addr.ipv4.sin_addr.s_addr = htonl((((((((unsigned)ip[0] << 8) |
(unsigned)ip[1]) << 8) |
(unsigned)ip[2]) << 8) |
(unsigned)ip[3]));
first->addr.ipv4.sin_port = htons(portnum);
}
}
else if ((host = gethostbyname(hostname)) != NULL &&
# ifdef AF_INET6
(host->h_addrtype == AF_INET || host->h_addrtype == AF_INET6))
# else
host->h_addrtype == AF_INET)
# endif /* AF_INET6 */
{
for (i = 0; host->h_addr_list[i]; i ++)
{
/*
* Copy the address over...
*/
temp = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t));
if (!temp)
{
httpAddrFreeList(first);
return (NULL);
}
# ifdef AF_INET6
if (host->h_addrtype == AF_INET6)
{
temp->addr.ipv6.sin6_family = AF_INET6;
memcpy(&(temp->addr.ipv6.sin6_addr), host->h_addr_list[i],
sizeof(temp->addr.ipv6));
temp->addr.ipv6.sin6_port = htons(portnum);
}
else
# endif /* AF_INET6 */
{
temp->addr.ipv4.sin_family = AF_INET;
memcpy(&(temp->addr.ipv4.sin_addr), host->h_addr_list[i],
sizeof(temp->addr.ipv4));
temp->addr.ipv4.sin_port = htons(portnum);
}
/*
* Append the address to the list...
*/
if (!first)
first = temp;
if (addr)
addr->next = temp;
addr = temp;
}
}
else
{
if (h_errno == NO_RECOVERY)
cg->need_res_init = 1;
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, hstrerror(h_errno), 0);
}
}
#endif /* HAVE_GETADDRINFO */
}
/*
* Detect some common errors and handle them sanely...
*/
if (!addr && (!hostname || !_cups_strcasecmp(hostname, "localhost")))
{
struct servent *port; /* Port number for service */
int portnum; /* Port number */
/*
* Lookup the service...
*/
if (!service)
portnum = 0;
else if (isdigit(*service & 255))
portnum = atoi(service);
else if ((port = getservbyname(service, NULL)) != NULL)
portnum = ntohs(port->s_port);
else if (!strcmp(service, "http"))
portnum = 80;
else if (!strcmp(service, "https"))
portnum = 443;
else if (!strcmp(service, "ipp") || !strcmp(service, "ipps"))
portnum = 631;
else if (!strcmp(service, "lpd"))
portnum = 515;
else if (!strcmp(service, "socket"))
portnum = 9100;
else
{
httpAddrFreeList(first);
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Unknown service name."), 1);
return (NULL);
}
if (hostname && !_cups_strcasecmp(hostname, "localhost"))
{
/*
* Unfortunately, some users ignore all of the warnings in the
* /etc/hosts file and delete "localhost" from it. If we get here
* then we were unable to resolve the name, so use the IPv6 and/or
* IPv4 loopback interface addresses...
*/
#ifdef AF_INET6
if (family != AF_INET)
{
/*
* Add [::1] to the address list...
*/
temp = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t));
if (!temp)
{
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), 0);
httpAddrFreeList(first);
return (NULL);
}
temp->addr.ipv6.sin6_family = AF_INET6;
temp->addr.ipv6.sin6_port = htons(portnum);
# ifdef WIN32
temp->addr.ipv6.sin6_addr.u.Byte[15] = 1;
# else
temp->addr.ipv6.sin6_addr.s6_addr32[3] = htonl(1);
# endif /* WIN32 */
if (!first)
first = temp;
addr = temp;
}
if (family != AF_INET6)
#endif /* AF_INET6 */
{
/*
* Add 127.0.0.1 to the address list...
*/
temp = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t));
if (!temp)
{
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), 0);
httpAddrFreeList(first);
return (NULL);
}
temp->addr.ipv4.sin_family = AF_INET;
temp->addr.ipv4.sin_port = htons(portnum);
temp->addr.ipv4.sin_addr.s_addr = htonl(0x7f000001);
if (!first)
first = temp;
if (addr)
addr->next = temp;
}
}
else if (!hostname)
{
/*
* Provide one or more passive listening addresses...
*/
#ifdef AF_INET6
if (family != AF_INET)
{
/*
* Add [::] to the address list...
*/
temp = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t));
if (!temp)
{
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), 0);
httpAddrFreeList(first);
return (NULL);
}
temp->addr.ipv6.sin6_family = AF_INET6;
temp->addr.ipv6.sin6_port = htons(portnum);
if (!first)
first = temp;
addr = temp;
}
if (family != AF_INET6)
#endif /* AF_INET6 */
{
/*
* Add 0.0.0.0 to the address list...
*/
temp = (http_addrlist_t *)calloc(1, sizeof(http_addrlist_t));
if (!temp)
{
_cupsSetError(IPP_STATUS_ERROR_INTERNAL, strerror(errno), 0);
httpAddrFreeList(first);
return (NULL);
}
temp->addr.ipv4.sin_family = AF_INET;
temp->addr.ipv4.sin_port = htons(portnum);
if (!first)
first = temp;
if (addr)
addr->next = temp;
}
}
}
/*
* Return the address list...
*/
return (first);
}