/* -*- Mode: C; tab-width: 4 -*-
*
* Copyright (c) 2002-2004 Apple Computer, Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mDNSUNP.h"
#include <errno.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include <sys/uio.h>
#include <sys/ioctl.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
/* Some weird platforms derived from 4.4BSD Lite (e.g. EFI) need the ALIGN(P)
macro, usually defined in <sys/param.h> or someplace like that, to make sure the
CMSG_NXTHDR macro is well-formed. On such platforms, the symbol NEED_ALIGN_MACRO
should be set to the name of the header to include to get the ALIGN(P) macro.
*/
#ifdef NEED_ALIGN_MACRO
#include NEED_ALIGN_MACRO
#endif
/* Solaris defined SIOCGIFCONF etc in <sys/sockio.h> but
other platforms don't even have that include file. So,
if we haven't yet got a definition, let's try to find
<sys/sockio.h>.
*/
#ifndef SIOCGIFCONF
#include <sys/sockio.h>
#endif
/* sockaddr_dl is only referenced if we're using IP_RECVIF,
so only include the header in that case.
*/
#ifdef IP_RECVIF
#include <net/if_dl.h>
#endif
#if defined(AF_INET6) && HAVE_IPV6 && !HAVE_LINUX
#include <net/if_var.h>
#include <netinet/in_var.h>
// Note: netinet/in_var.h implicitly includes netinet6/in6_var.h for us
#endif
#if defined(AF_INET6) && HAVE_IPV6 && HAVE_LINUX
#include <netdb.h>
#include <arpa/inet.h>
/* Converts a prefix length to IPv6 network mask */
void plen_to_mask(int plen, char *addr) {
int i;
int colons=7; /* Number of colons in IPv6 address */
int bits_in_block=16; /* Bits per IPv6 block */
for(i=0;i<=colons;i++) {
int block, ones=0xffff, ones_in_block;
if (plen>bits_in_block) ones_in_block=bits_in_block;
else ones_in_block=plen;
block = ones & (ones << (bits_in_block-ones_in_block));
i==0 ? sprintf(addr, "%x", block) : sprintf(addr, "%s:%x", addr, block);
plen -= ones_in_block;
}
}
/* Gets IPv6 interface information from the /proc filesystem in linux*/
struct ifi_info *get_ifi_info_linuxv6(int family, int doaliases)
{
struct ifi_info *ifi, *ifihead, **ifipnext, *ifipold, **ifiptr;
FILE *fp = NULL;
char addr[8][5];
int flags, myflags, index, plen, scope;
char ifname[IFNAMSIZ], lastname[IFNAMSIZ];
char addr6[32+7+1]; /* don't forget the seven ':' */
struct addrinfo hints, *res0;
struct sockaddr_in6 *sin6;
struct in6_addr *addrptr;
int err;
int sockfd = -1;
struct ifreq ifr;
res0=NULL;
ifihead = NULL;
ifipnext = &ifihead;
lastname[0] = 0;
if ((fp = fopen(PROC_IFINET6_PATH, "r")) != NULL) {
sockfd = socket(AF_INET6, SOCK_DGRAM, 0);
if (sockfd < 0) {
goto gotError;
}
while (fscanf(fp,
"%4s%4s%4s%4s%4s%4s%4s%4s %02x %02x %02x %02x %15s\n",
addr[0],addr[1],addr[2],addr[3],
addr[4],addr[5],addr[6],addr[7],
&index, &plen, &scope, &flags, ifname) != EOF) {
myflags = 0;
if (strncmp(lastname, ifname, IFNAMSIZ) == 0) {
if (doaliases == 0)
continue; /* already processed this interface */
myflags = IFI_ALIAS;
}
strncpy(lastname, ifname, IFNAMSIZ);
ifi = (struct ifi_info*)calloc(1, sizeof(struct ifi_info));
if (ifi == NULL) {
goto gotError;
}
ifipold = *ifipnext; /* need this later */
ifiptr = ifipnext;
*ifipnext = ifi; /* prev points to this new one */
ifipnext = &ifi->ifi_next; /* pointer to next one goes here */
sprintf(addr6, "%s:%s:%s:%s:%s:%s:%s:%s",
addr[0],addr[1],addr[2],addr[3],
addr[4],addr[5],addr[6],addr[7]);
/* Add address of the interface */
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET6;
hints.ai_flags = AI_NUMERICHOST;
err = getaddrinfo(addr6, NULL, &hints, &res0);
if (err) {
goto gotError;
}
ifi->ifi_addr = calloc(1, sizeof(struct sockaddr_in6));
if (ifi->ifi_addr == NULL) {
goto gotError;
}
memcpy(ifi->ifi_addr, res0->ai_addr, sizeof(struct sockaddr_in6));
/* Add netmask of the interface */
char ipv6addr[INET6_ADDRSTRLEN];
plen_to_mask(plen, ipv6addr);
ifi->ifi_netmask = calloc(1, sizeof(struct sockaddr_in6));
if (ifi->ifi_addr == NULL) {
goto gotError;
}
sin6=calloc(1, sizeof(struct sockaddr_in6));
addrptr=calloc(1, sizeof(struct in6_addr));
inet_pton(family, ipv6addr, addrptr);
sin6->sin6_family=family;
sin6->sin6_addr=*addrptr;
sin6->sin6_scope_id=scope;
memcpy(ifi->ifi_netmask, sin6, sizeof(struct sockaddr_in6));
free(sin6);
/* Add interface name */
strncpy(ifi->ifi_name, ifname, IFI_NAME);
/* Add interface index */
ifi->ifi_index = index;
/* Add interface flags*/
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
if (ioctl(sockfd, SIOCGIFFLAGS, &ifr) < 0) {
if (errno == EADDRNOTAVAIL) {
/*
* If the main interface is configured with no IP address but
* an alias interface exists with an IP address, you get
* EADDRNOTAVAIL for the main interface
*/
free(ifi->ifi_addr);
free(ifi);
ifipnext = ifiptr;
*ifipnext = ifipold;
continue;
} else {
goto gotError;
}
}
ifi->ifi_flags = ifr.ifr_flags;
freeaddrinfo(res0);
res0=NULL;
}
}
goto done;
gotError:
if (ifihead != NULL) {
free_ifi_info(ifihead);
ifihead = NULL;
}
if (res0 != NULL) {
freeaddrinfo(res0);
res0=NULL;
}
done:
if (sockfd != -1) {
// __ANDROID__ : replaced assert(close(..))
int sockfd_closed = close(sockfd);
assert(sockfd_closed == 0);
}
// __ANDROID__ : if fp was opened, it needs to be closed
if (fp != NULL) {
int fd_closed = fclose(fp);
assert(fd_closed == 0);
}
return(ifihead); /* pointer to first structure in linked list */
}
#endif // defined(AF_INET6) && HAVE_IPV6 && HAVE_LINUX
struct ifi_info *get_ifi_info(int family, int doaliases)
{
int junk;
struct ifi_info *ifi, *ifihead, **ifipnext, *ifipold, **ifiptr;
int sockfd, sockf6, len, lastlen, flags, myflags;
#ifdef NOT_HAVE_IF_NAMETOINDEX
int index = 200;
#endif
char *ptr, *buf, lastname[IFNAMSIZ], *cptr;
struct ifconf ifc;
struct ifreq *ifr, ifrcopy;
struct sockaddr_in *sinptr;
#if defined(AF_INET6) && HAVE_IPV6
struct sockaddr_in6 *sinptr6;
#endif
#if defined(AF_INET6) && HAVE_IPV6 && HAVE_LINUX
if (family == AF_INET6) return get_ifi_info_linuxv6(family, doaliases);
#endif
sockfd = -1;
sockf6 = -1;
buf = NULL;
ifihead = NULL;
sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd < 0) {
goto gotError;
}
lastlen = 0;
len = 100 * sizeof(struct ifreq); /* initial buffer size guess */
for ( ; ; ) {
buf = (char*)malloc(len);
if (buf == NULL) {
goto gotError;
}
ifc.ifc_len = len;
ifc.ifc_buf = buf;
if (ioctl(sockfd, SIOCGIFCONF, &ifc) < 0) {
if (errno != EINVAL || lastlen != 0) {
goto gotError;
}
} else {
if (ifc.ifc_len == lastlen)
break; /* success, len has not changed */
lastlen = ifc.ifc_len;
}
len += 10 * sizeof(struct ifreq); /* increment */
free(buf);
}
ifihead = NULL;
ifipnext = &ifihead;
lastname[0] = 0;
/* end get_ifi_info1 */
/* include get_ifi_info2 */
for (ptr = buf; ptr < buf + ifc.ifc_len; ) {
ifr = (struct ifreq *) ptr;
/* Advance to next one in buffer */
if (sizeof(struct ifreq) > sizeof(ifr->ifr_name) + GET_SA_LEN(ifr->ifr_addr))
ptr += sizeof(struct ifreq);
else
ptr += sizeof(ifr->ifr_name) + GET_SA_LEN(ifr->ifr_addr);
// fprintf(stderr, "intf %p name=%s AF=%d\n", index, ifr->ifr_name, ifr->ifr_addr.sa_family);
if (ifr->ifr_addr.sa_family != family)
continue; /* ignore if not desired address family */
myflags = 0;
if ( (cptr = strchr(ifr->ifr_name, ':')) != NULL)
*cptr = 0; /* replace colon will null */
if (strncmp(lastname, ifr->ifr_name, IFNAMSIZ) == 0) {
if (doaliases == 0)
continue; /* already processed this interface */
myflags = IFI_ALIAS;
}
memcpy(lastname, ifr->ifr_name, IFNAMSIZ);
ifrcopy = *ifr;
if (ioctl(sockfd, SIOCGIFFLAGS, &ifrcopy) < 0) {
goto gotError;
}
flags = ifrcopy.ifr_flags;
if ((flags & IFF_UP) == 0)
continue; /* ignore if interface not up */
ifi = (struct ifi_info*)calloc(1, sizeof(struct ifi_info));
if (ifi == NULL) {
goto gotError;
}
ifipold = *ifipnext; /* need this later */
ifiptr = ifipnext;
*ifipnext = ifi; /* prev points to this new one */
ifipnext = &ifi->ifi_next; /* pointer to next one goes here */
ifi->ifi_flags = flags; /* IFF_xxx values */
ifi->ifi_myflags = myflags; /* IFI_xxx values */
#ifndef NOT_HAVE_IF_NAMETOINDEX
ifi->ifi_index = if_nametoindex(ifr->ifr_name);
#else
ifrcopy = *ifr;
#ifdef SIOCGIFINDEX
if ( 0 >= ioctl(sockfd, SIOCGIFINDEX, &ifrcopy))
ifi->ifi_index = ifrcopy.ifr_index;
else
#endif
ifi->ifi_index = index++; /* SIOCGIFINDEX is broken on Solaris 2.5ish, so fake it */
#endif
memcpy(ifi->ifi_name, ifr->ifr_name, IFI_NAME);
ifi->ifi_name[IFI_NAME-1] = '\0';
/* end get_ifi_info2 */
/* include get_ifi_info3 */
switch (ifr->ifr_addr.sa_family) {
case AF_INET:
sinptr = (struct sockaddr_in *) &ifr->ifr_addr;
if (ifi->ifi_addr == NULL) {
ifi->ifi_addr = (struct sockaddr*)calloc(1, sizeof(struct sockaddr_in));
if (ifi->ifi_addr == NULL) {
goto gotError;
}
memcpy(ifi->ifi_addr, sinptr, sizeof(struct sockaddr_in));
#ifdef SIOCGIFNETMASK
if (ioctl(sockfd, SIOCGIFNETMASK, &ifrcopy) < 0) {
if (errno == EADDRNOTAVAIL) {
/*
* If the main interface is configured with no IP address but
* an alias interface exists with an IP address, you get
* EADDRNOTAVAIL for the main interface
*/
free(ifi->ifi_addr);
free(ifi);
ifipnext = ifiptr;
*ifipnext = ifipold;
continue;
} else {
goto gotError;
}
}
ifi->ifi_netmask = (struct sockaddr*)calloc(1, sizeof(struct sockaddr_in));
if (ifi->ifi_netmask == NULL) goto gotError;
sinptr = (struct sockaddr_in *) &ifrcopy.ifr_addr;
/* The BSD ioctls (including Mac OS X) stick some weird values in for sin_len and sin_family */
#ifndef NOT_HAVE_SA_LEN
sinptr->sin_len = sizeof(struct sockaddr_in);
#endif
sinptr->sin_family = AF_INET;
memcpy(ifi->ifi_netmask, sinptr, sizeof(struct sockaddr_in));
#endif
#ifdef SIOCGIFBRDADDR
if (flags & IFF_BROADCAST) {
if (ioctl(sockfd, SIOCGIFBRDADDR, &ifrcopy) < 0) {
goto gotError;
}
sinptr = (struct sockaddr_in *) &ifrcopy.ifr_broadaddr;
/* The BSD ioctls (including Mac OS X) stick some weird values in for sin_len and sin_family */
#ifndef NOT_HAVE_SA_LEN
sinptr->sin_len = sizeof( struct sockaddr_in );
#endif
sinptr->sin_family = AF_INET;
ifi->ifi_brdaddr = (struct sockaddr*)calloc(1, sizeof(struct sockaddr_in));
if (ifi->ifi_brdaddr == NULL) {
goto gotError;
}
memcpy(ifi->ifi_brdaddr, sinptr, sizeof(struct sockaddr_in));
}
#endif
#ifdef SIOCGIFDSTADDR
if (flags & IFF_POINTOPOINT) {
if (ioctl(sockfd, SIOCGIFDSTADDR, &ifrcopy) < 0) {
goto gotError;
}
sinptr = (struct sockaddr_in *) &ifrcopy.ifr_dstaddr;
/* The BSD ioctls (including Mac OS X) stick some weird values in for sin_len and sin_family */
#ifndef NOT_HAVE_SA_LEN
sinptr->sin_len = sizeof( struct sockaddr_in );
#endif
sinptr->sin_family = AF_INET;
ifi->ifi_dstaddr = (struct sockaddr*)calloc(1, sizeof(struct sockaddr_in));
if (ifi->ifi_dstaddr == NULL) {
goto gotError;
}
memcpy(ifi->ifi_dstaddr, sinptr, sizeof(struct sockaddr_in));
}
#endif
}
break;
#if defined(AF_INET6) && HAVE_IPV6
case AF_INET6:
sinptr6 = (struct sockaddr_in6 *) &ifr->ifr_addr;
if (ifi->ifi_addr == NULL) {
ifi->ifi_addr = calloc(1, sizeof(struct sockaddr_in6));
if (ifi->ifi_addr == NULL) {
goto gotError;
}
/* Some platforms (*BSD) inject the prefix in IPv6LL addresses */
/* We need to strip that out */
if (IN6_IS_ADDR_LINKLOCAL(&sinptr6->sin6_addr))
sinptr6->sin6_addr.s6_addr[2] = sinptr6->sin6_addr.s6_addr[3] = 0;
memcpy(ifi->ifi_addr, sinptr6, sizeof(struct sockaddr_in6));
#ifdef SIOCGIFNETMASK_IN6
{
struct in6_ifreq ifr6;
if (sockf6 == -1)
sockf6 = socket(AF_INET6, SOCK_DGRAM, 0);
memset(&ifr6, 0, sizeof(ifr6));
memcpy(&ifr6.ifr_name, &ifr->ifr_name, sizeof(ifr6.ifr_name ));
memcpy(&ifr6.ifr_ifru.ifru_addr, &ifr->ifr_addr, sizeof(ifr6.ifr_ifru.ifru_addr));
if (ioctl(sockf6, SIOCGIFNETMASK_IN6, &ifr6) < 0) {
if (errno == EADDRNOTAVAIL) {
/*
* If the main interface is configured with no IP address but
* an alias interface exists with an IP address, you get
* EADDRNOTAVAIL for the main interface
*/
free(ifi->ifi_addr);
free(ifi);
ifipnext = ifiptr;
*ifipnext = ifipold;
continue;
} else {
goto gotError;
}
}
ifi->ifi_netmask = (struct sockaddr*)calloc(1, sizeof(struct sockaddr_in6));
if (ifi->ifi_netmask == NULL) goto gotError;
sinptr6 = (struct sockaddr_in6 *) &ifr6.ifr_ifru.ifru_addr;
memcpy(ifi->ifi_netmask, sinptr6, sizeof(struct sockaddr_in6));
}
#endif
}
break;
#endif
default:
break;
}
}
goto done;
gotError:
if (ifihead != NULL) {
free_ifi_info(ifihead);
ifihead = NULL;
}
done:
if (buf != NULL) {
free(buf);
}
if (sockfd != -1) {
junk = close(sockfd);
assert(junk == 0);
}
if (sockf6 != -1) {
junk = close(sockf6);
assert(junk == 0);
}
return(ifihead); /* pointer to first structure in linked list */
}
/* end get_ifi_info3 */
/* include free_ifi_info */
void
free_ifi_info(struct ifi_info *ifihead)
{
struct ifi_info *ifi, *ifinext;
for (ifi = ifihead; ifi != NULL; ifi = ifinext) {
if (ifi->ifi_addr != NULL)
free(ifi->ifi_addr);
if (ifi->ifi_netmask != NULL)
free(ifi->ifi_netmask);
if (ifi->ifi_brdaddr != NULL)
free(ifi->ifi_brdaddr);
if (ifi->ifi_dstaddr != NULL)
free(ifi->ifi_dstaddr);
ifinext = ifi->ifi_next; /* can't fetch ifi_next after free() */
free(ifi); /* the ifi_info{} itself */
}
}
/* end free_ifi_info */
ssize_t
recvfrom_flags(int fd, void *ptr, size_t nbytes, int *flagsp,
struct sockaddr *sa, socklen_t *salenptr, struct my_in_pktinfo *pktp, u_char *ttl)
{
struct msghdr msg;
struct iovec iov[1];
ssize_t n;
#ifdef CMSG_FIRSTHDR
struct cmsghdr *cmptr;
union {
struct cmsghdr cm;
char control[1024];
} control_un;
*ttl = 255; // If kernel fails to provide TTL data then assume the TTL was 255 as it should be
msg.msg_control = control_un.control;
msg.msg_controllen = sizeof(control_un.control);
msg.msg_flags = 0;
#else
memset(&msg, 0, sizeof(msg)); /* make certain msg_accrightslen = 0 */
#endif /* CMSG_FIRSTHDR */
msg.msg_name = (char *) sa;
msg.msg_namelen = *salenptr;
iov[0].iov_base = (char *)ptr;
iov[0].iov_len = nbytes;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
if ( (n = recvmsg(fd, &msg, *flagsp)) < 0)
return(n);
*salenptr = msg.msg_namelen; /* pass back results */
if (pktp) {
/* 0.0.0.0, i/f = -1 */
/* We set the interface to -1 so that the caller can
tell whether we returned a meaningful value or
just some default. Previously this code just
set the value to 0, but I'm concerned that 0
might be a valid interface value.
*/
memset(pktp, 0, sizeof(struct my_in_pktinfo));
pktp->ipi_ifindex = -1;
}
/* end recvfrom_flags1 */
/* include recvfrom_flags2 */
#ifndef CMSG_FIRSTHDR
#warning CMSG_FIRSTHDR not defined. Will not be able to determine destination address, received interface, etc.
*flagsp = 0; /* pass back results */
return(n);
#else
*flagsp = msg.msg_flags; /* pass back results */
if (msg.msg_controllen < (socklen_t)sizeof(struct cmsghdr) ||
(msg.msg_flags & MSG_CTRUNC) || pktp == NULL)
return(n);
for (cmptr = CMSG_FIRSTHDR(&msg); cmptr != NULL;
cmptr = CMSG_NXTHDR(&msg, cmptr)) {
#ifdef IP_PKTINFO
#if in_pktinfo_definition_is_missing
struct in_pktinfo
{
int ipi_ifindex;
struct in_addr ipi_spec_dst;
struct in_addr ipi_addr;
};
#endif
if (cmptr->cmsg_level == IPPROTO_IP &&
cmptr->cmsg_type == IP_PKTINFO) {
struct in_pktinfo *tmp;
struct sockaddr_in *sin = (struct sockaddr_in*)&pktp->ipi_addr;
tmp = (struct in_pktinfo *) CMSG_DATA(cmptr);
sin->sin_family = AF_INET;
sin->sin_addr = tmp->ipi_addr;
sin->sin_port = 0;
pktp->ipi_ifindex = tmp->ipi_ifindex;
continue;
}
#endif
#ifdef IP_RECVDSTADDR
if (cmptr->cmsg_level == IPPROTO_IP &&
cmptr->cmsg_type == IP_RECVDSTADDR) {
struct sockaddr_in *sin = (struct sockaddr_in*)&pktp->ipi_addr;
sin->sin_family = AF_INET;
sin->sin_addr = *(struct in_addr*)CMSG_DATA(cmptr);
sin->sin_port = 0;
continue;
}
#endif
#ifdef IP_RECVIF
if (cmptr->cmsg_level == IPPROTO_IP &&
cmptr->cmsg_type == IP_RECVIF) {
struct sockaddr_dl *sdl = (struct sockaddr_dl *) CMSG_DATA(cmptr);
#ifndef HAVE_BROKEN_RECVIF_NAME
int nameLen = (sdl->sdl_nlen < IFI_NAME - 1) ? sdl->sdl_nlen : (IFI_NAME - 1);
strncpy(pktp->ipi_ifname, sdl->sdl_data, nameLen);
#endif
pktp->ipi_ifindex = sdl->sdl_index;
#ifdef HAVE_BROKEN_RECVIF_NAME
if (sdl->sdl_index == 0) {
pktp->ipi_ifindex = *(uint_t*)sdl;
}
#endif
assert(pktp->ipi_ifname[IFI_NAME - 1] == 0);
// null terminated because of memset above
continue;
}
#endif
#ifdef IP_RECVTTL
if (cmptr->cmsg_level == IPPROTO_IP &&
cmptr->cmsg_type == IP_RECVTTL) {
*ttl = *(u_char*)CMSG_DATA(cmptr);
continue;
}
else if (cmptr->cmsg_level == IPPROTO_IP &&
cmptr->cmsg_type == IP_TTL) { // some implementations seem to send IP_TTL instead of IP_RECVTTL
*ttl = *(int*)CMSG_DATA(cmptr);
continue;
}
#endif
#if defined(IPV6_PKTINFO) && HAVE_IPV6
if (cmptr->cmsg_level == IPPROTO_IPV6 &&
cmptr->cmsg_type == IPV6_2292_PKTINFO) {
struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&pktp->ipi_addr;
struct in6_pktinfo *ip6_info = (struct in6_pktinfo*)CMSG_DATA(cmptr);
sin6->sin6_family = AF_INET6;
#ifndef NOT_HAVE_SA_LEN
sin6->sin6_len = sizeof(*sin6);
#endif
sin6->sin6_addr = ip6_info->ipi6_addr;
sin6->sin6_flowinfo = 0;
sin6->sin6_scope_id = 0;
sin6->sin6_port = 0;
pktp->ipi_ifindex = ip6_info->ipi6_ifindex;
continue;
}
#endif
#if defined(IPV6_HOPLIMIT) && HAVE_IPV6
if (cmptr->cmsg_level == IPPROTO_IPV6 &&
cmptr->cmsg_type == IPV6_2292_HOPLIMIT) {
*ttl = *(int*)CMSG_DATA(cmptr);
continue;
}
#endif
assert(0); // unknown ancillary data
}
return(n);
#endif /* CMSG_FIRSTHDR */
}
// **********************************************************************************************
// daemonize the process. Adapted from "Unix Network Programming" vol 1 by Stevens, section 12.4.
// Returns 0 on success, -1 on failure.
#ifdef NOT_HAVE_DAEMON
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/signal.h>
int daemon(int nochdir, int noclose)
{
switch (fork())
{
case -1: return (-1); // Fork failed
case 0: break; // Child -- continue
default: _exit(0); // Parent -- exit
}
if (setsid() == -1) return(-1);
signal(SIGHUP, SIG_IGN);
switch (fork()) // Fork again, primarily for reasons of Unix trivia
{
case -1: return (-1); // Fork failed
case 0: break; // Child -- continue
default: _exit(0); // Parent -- exit
}
if (!nochdir) (void)chdir("/");
umask(0);
if (!noclose)
{
int fd = open("/dev/null", O_RDWR, 0);
if (fd != -1)
{
// Avoid unnecessarily duplicating a file descriptor to itself
if (fd != STDIN_FILENO) (void)dup2(fd, STDIN_FILENO);
if (fd != STDOUT_FILENO) (void)dup2(fd, STDOUT_FILENO);
if (fd != STDERR_FILENO) (void)dup2(fd, STDERR_FILENO);
if (fd != STDIN_FILENO && fd != STDOUT_FILENO && fd != STDERR_FILENO)
(void)close (fd);
}
}
return (0);
}
#endif /* NOT_HAVE_DAEMON */