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| -rw-r--r-- | sysdeps/unix/sysv/linux/opensock.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/opensock.c b/sysdeps/unix/sysv/linux/opensock.c new file mode 100644 index 0000000000..a3c55a94e8 --- /dev/null +++ b/sysdeps/unix/sysv/linux/opensock.c @@ -0,0 +1,111 @@ +/* Copyright (C) 1999, 2001 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <assert.h> +#include <errno.h> +#include <stdio.h> +#include <unistd.h> +#include <sys/socket.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" } + }; +#define nafs (sizeof (afs) / sizeof (afs[0])) + char fname[sizeof "/proc/" + 14]; + int result; + int has_proc; + int cnt; + + /* We already know which family to use from the last call. Use it + again. */ + if (last_family != 0) + { + assert (last_type != 0); + + result = socket (last_family, last_type, 0); + 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; + + result = socket (afs[cnt].family, type, 0); + 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; +} |