| /* Copyright (C) 1999-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library 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. |
| |
| The GNU C Library 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 the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <sys/socket.h> |
| #include <kernel-features.h> |
| |
| /* Return a socket of any type. The socket can be used in subsequent |
| ioctl calls to talk to the kernel. */ |
| int internal_function |
| __opensock (void) |
| { |
| static int last_family; /* Available socket family we will use. */ |
| static int last_type; |
| static const struct |
| { |
| int family; |
| const char procname[15]; |
| } afs[] = |
| { |
| { AF_UNIX, "net/unix" }, |
| { AF_INET, "" }, |
| { AF_INET6, "net/if_inet6" }, |
| { AF_AX25, "net/ax25" }, |
| { AF_NETROM, "net/nr" }, |
| { AF_ROSE, "net/rose" }, |
| { AF_IPX, "net/ipx" }, |
| { AF_APPLETALK, "net/appletalk" }, |
| { AF_ECONET, "sys/net/econet" }, |
| { AF_ASH, "sys/net/ash" }, |
| { AF_X25, "net/x25" }, |
| #ifdef NEED_AF_IUCV |
| { AF_IUCV, "net/iucv" } |
| #endif |
| }; |
| #define nafs (sizeof (afs) / sizeof (afs[0])) |
| char fname[sizeof "/proc/" + 14]; |
| int result; |
| int has_proc; |
| size_t cnt; |
| |
| /* We already know which family to use from the last call. Use it |
| again. */ |
| if (last_family != 0) |
| { |
| assert (last_type != 0); |
| |
| #ifdef SOCK_CLOEXEC |
| # ifndef __ASSUME_SOCK_CLOEXEC |
| if (__have_sock_cloexec >= 0) |
| # endif |
| { |
| result = __socket (last_family, last_type | SOCK_CLOEXEC, 0); |
| # ifndef __ASSUME_SOCK_CLOEXEC |
| if (__have_sock_cloexec == 0) |
| __have_sock_cloexec = result != -1 || errno != EINVAL ? 1 : -1; |
| # endif |
| } |
| #endif |
| #ifndef __ASSUME_SOCK_CLOEXEC |
| # ifdef SOCK_CLOEXEC |
| if (__have_sock_cloexec < 0) |
| # endif |
| result = __socket (last_family, last_type, 0); |
| #endif |
| if (result != -1 || errno != EAFNOSUPPORT) |
| /* Maybe the socket type isn't supported anymore (module is |
| unloaded). In this case again try to find the type. */ |
| return result; |
| |
| /* Reset the values. They seem not valid anymore. */ |
| last_family = 0; |
| last_type = 0; |
| } |
| |
| /* Check whether the /proc filesystem is available. */ |
| has_proc = __access ("/proc/net", R_OK) != -1; |
| strcpy (fname, "/proc/"); |
| |
| /* Iterate over the interface families and find one which is |
| available. */ |
| for (cnt = 0; cnt < nafs; ++cnt) |
| { |
| int type = SOCK_DGRAM; |
| |
| if (has_proc && afs[cnt].procname[0] != '\0') |
| { |
| strcpy (fname + 6, afs[cnt].procname); |
| if (__access (fname, R_OK) == -1) |
| /* The /proc entry is not available. I.e., we cannot |
| create a socket of this type (without loading the |
| module). Don't look for it since this might trigger |
| loading the module. */ |
| continue; |
| } |
| |
| if (afs[cnt].family == AF_NETROM || afs[cnt].family == AF_X25) |
| type = SOCK_SEQPACKET; |
| |
| #ifdef SOCK_CLOEXEC |
| # ifndef __ASSUME_SOCK_CLOEXEC |
| if (__have_sock_cloexec >= 0) |
| # endif |
| { |
| result = __socket (afs[cnt].family, type | SOCK_CLOEXEC, 0); |
| # ifndef __ASSUME_SOCK_CLOEXEC |
| if (__have_sock_cloexec == 0) |
| __have_sock_cloexec = result != -1 || errno != EINVAL ? 1 : -1; |
| # endif |
| } |
| #endif |
| #ifndef __ASSUME_SOCK_CLOEXEC |
| # ifdef SOCK_CLOEXEC |
| if (__have_sock_cloexec < 0) |
| # endif |
| result = __socket (afs[cnt].family, type, 0); |
| #endif |
| if (result != -1) |
| { |
| /* Found an available family. */ |
| last_type = type; |
| last_family = afs[cnt].family; |
| return result; |
| } |
| } |
| |
| /* None of the protocol families is available. It is unclear what kind |
| of error is returned. ENOENT seems like a reasonable choice. */ |
| __set_errno (ENOENT); |
| return -1; |
| } |