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/*
* libexplain - Explain errno values returned by libc functions
* Copyright (C) 2008-2010, 2013 Peter Miller
*
* This program 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 3 of the License, or (at
* your option) any later version.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <libexplain/ac/errno.h>
#include <libexplain/ac/string.h>
#include <libexplain/ac/sys/socket.h>
#include <libexplain/ac/unistd.h>
#include <libexplain/buffer/ebadf.h>
#include <libexplain/buffer/enotsock.h>
#include <libexplain/buffer/errno/generic.h>
#include <libexplain/buffer/errno/listen.h>
#include <libexplain/buffer/gettext.h>
#include <libexplain/buffer/sockaddr.h>
#include <libexplain/buffer/socket_type.h>
#include <libexplain/explanation.h>
#include <libexplain/option.h>
#include <libexplain/sizeof.h>
static void
explain_buffer_errno_listen_system_call(explain_string_buffer_t *sb,
int errnum, int fildes, int backlog)
{
(void)errnum;
explain_string_buffer_puts(sb, "listen(");
explain_string_buffer_printf(sb, "fildes = %d", fildes);
explain_string_buffer_puts(sb, ", ");
explain_string_buffer_printf(sb, "backlog = %d", backlog);
explain_string_buffer_putc(sb, ')');
}
static void
append_getsockname(explain_string_buffer_t *sb, int fildes)
{
struct sockaddr_storage sas;
struct sockaddr *sa;
socklen_t sa_len;
sa = (struct sockaddr *)&sas;
sa_len = sizeof(sas);
if (getsockname(fildes, sa, &sa_len) >= 0)
{
explain_string_buffer_putc(sb, ' ');
explain_buffer_sockaddr(sb, sa, sa_len);
}
}
#ifdef __linux__
#include <sys/syscall.h>
#include <linux/sysctl.h>
#endif
static int
get_somaxconn(void)
{
#if defined(__linux__) && defined(SYS__sysctl)
struct __sysctl_args args;
long somaxconn;
size_t somaxconn_size = sizeof(somaxconn);
int name[] = { CTL_NET, NET_CORE_SOMAXCONN };
memset(&args, 0, sizeof(struct __sysctl_args));
args.name = name;
args.nlen = SIZEOF(name);
args.oldval = &somaxconn;
args.oldlenp = &somaxconn_size;
if (syscall(SYS__sysctl, &args) >= 0)
return somaxconn;
#endif
#ifdef SOMAXCONN
return SOMAXCONN;
#else
return -1;
#endif
}
static void
explain_buffer_errno_listen_explanation(explain_string_buffer_t *sb,
int errnum, int fildes, int backlog)
{
/*
* http://www.opengroup.org/onlinepubs/009695399/functions/listen.html
*/
switch (errnum)
{
case EADDRINUSE:
explain_buffer_gettext
(
sb,
/*
* xgettext: This message is used to explain an EADDRINUSE error.
*/
i18n("another socket is already listening on the same port")
);
append_getsockname(sb, fildes);
break;
case EBADF:
explain_buffer_ebadf(sb, fildes, "fildes");
break;
case ENOTSOCK:
explain_buffer_enotsock(sb, fildes, "fildes");
break;
case EOPNOTSUPP:
explain_buffer_gettext
(
sb,
/*
* xgettext: This message is used to explain an EOPNOTSUPP
* error returned by a listen(2) system call.
*/
i18n("the socket is not of a type that supports the "
"listen(2) system call")
);
explain_buffer_socket_type_from_fildes(sb, fildes);
break;
case EDESTADDRREQ:
explain_buffer_gettext
(
sb,
/*
* xgettext: This message is used to explain an EDESTADDRREQ
* error returned by a listen(2) system call.
*/
i18n("the socket is not bound to a local address, and the "
"protocol does not support listening on an unbound socket")
);
append_getsockname(sb, fildes);
explain_buffer_socket_type_from_fildes(sb, fildes);
break;
case EINVAL:
/* FIXME: which is it? */
explain_buffer_gettext
(
sb,
/*
* xgettext: This message is used to explain an EINVAL
* error returned by a listen(2) system call.
*/
i18n("the socket is already connected, or the socket has "
"been shut down")
);
append_getsockname(sb, fildes);
break;
default:
explain_buffer_errno_generic(sb, errnum, "listen");
break;
}
if (explain_option_dialect_specific())
{
int somaxconn;
somaxconn = get_somaxconn();
if (somaxconn > 0 && backlog > somaxconn)
{
explain_string_buffer_puts(sb->footnotes, "; ");
explain_string_buffer_printf_gettext
(
sb->footnotes,
/*
* xgettext: This message is used to inform users of the
* listen(2) system call when they specify a backlog
* valie in excess of SOMAXCONN.
*
* %1$d => The maximum queue length for completely
* established sockets waiting to be accepted.
*/
i18n("large backlog values are silently truncated to the "
"system maximum (SOMAXCONN, %d)"),
somaxconn
);
}
}
}
void
explain_buffer_errno_listen(explain_string_buffer_t *sb, int errnum,
int fildes, int backlog)
{
explain_explanation_t exp;
explain_explanation_init(&exp, errnum);
explain_buffer_errno_listen_system_call
(
&exp.system_call_sb,
errnum,
fildes,
backlog
);
explain_buffer_errno_listen_explanation
(
&exp.explanation_sb,
errnum,
fildes,
backlog
);
explain_explanation_assemble(&exp, sb);
}
/* vim: set ts=8 sw=4 et : */
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