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/*
* Socket-related functions
* Copyright Jan Engelhardt, 2021
*
* This file is part of libHX. libHX 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 or (at your option) any later version.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
# include <ws2tcpip.h>
#else
# include <sys/socket.h>
# include <netdb.h>
#endif
#include <libHX/proc.h>
#include <libHX/socket.h>
#include "internal.h"
#ifdef _WIN32
# define STUPIDWIN(x) reinterpret_cast(char *, (x))
#else
# define STUPIDWIN(x) (x)
#endif
#if defined(__sunos__) && !defined(SO_PROTOCOL)
# define SO_PROTOCOL SO_PROTOTYPE
#endif
static int try_sk_from_env(int fd, const struct addrinfo *ai, const char *intf)
{
int value = 0;
socklen_t optlen = sizeof(value);
int ret = getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, STUPIDWIN(&value), &optlen);
if (ret < 0 && errno != ENOPROTOOPT)
/*
* E.g. OpenBSD's getsockopt does not recognize this - even
* though the flag with the same name exists and is known.
*/
return -1;
if (ret == 0 && value == 0)
return -1;
#ifdef _WIN32
WSAPROTOCOL_INFO protinfo;
optlen = sizeof(protinfo);
ret = getsockopt(fd, SOL_SOCKET, SO_PROTOCOL_INFO, STUPIDWIN(&protinfo), &optlen);
if (ret < 0 || protinfo.iAddressFamily != ai->ai_family ||
protinfo.iSocketType != ai->ai_socktype ||
protinfo.iProtocol != ai->ai_protocol)
return -1;
#else
optlen = sizeof(value);
ret = getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &value, &optlen);
if (ret < 0 || value != ai->ai_family)
return -1;
optlen = sizeof(value);
ret = getsockopt(fd, SOL_SOCKET, SO_TYPE, &value, &optlen);
if (ret < 0 || value != ai->ai_socktype)
return -1;
optlen = sizeof(value);
ret = getsockopt(fd, SOL_SOCKET, SO_PROTOCOL, &value, &optlen);
if (ret < 0 || value != ai->ai_protocol)
return -1;
#endif
struct sockaddr_storage addr;
memset(&addr, 0, sizeof(addr));
optlen = sizeof(addr);
ret = getsockname(fd, (struct sockaddr *)&addr, &optlen);
if (ret < 0)
return -1;
if (sizeof(addr) < optlen)
optlen = sizeof(addr);
if (optlen != ai->ai_addrlen || memcmp(&addr, ai->ai_addr, optlen) != 0)
return -1;
if (intf == nullptr)
return fd;
#ifdef SO_BINDTODEVICE
char ifname[32];
optlen = sizeof(ifname);
ret = getsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, ifname, &optlen);
if (ret < 0)
return -1;
else if (optlen < sizeof(ifname))
ifname[optlen] = '\0';
else
ifname[sizeof(ifname)-1] = '\0';
if (strcmp(intf, ifname) != 0)
return -1;
#endif
return fd;
}
EXPORT_SYMBOL int HX_socket_from_env(const struct addrinfo *ai, const char *intf)
{
int top_fd;
const char *env_limit = getenv("LISTEN_FDS");
if (env_limit != nullptr) {
long x = strtol(env_limit, nullptr, 0);
if (x > INT_MAX - 3)
x = INT_MAX - 3;
top_fd = 3 + x;
} else {
env_limit = getenv("HX_LISTEN_TOP_FD");
long x;
if (env_limit != nullptr) {
x = strtol(env_limit, nullptr, 0);
if (x > INT_MAX)
x = INT_MAX;
} else {
x = HXproc_top_fd();
}
top_fd = x;
}
for (int fd = 3; fd < top_fd; ++fd)
if (try_sk_from_env(fd, ai, intf) == fd)
return fd;
errno = ENOENT;
return -1;
}
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