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/* addrpeek - testing service for Inetd: remote address, environment vars
Copyright (C) 2010-2025 Free Software Foundation, Inc.
This file is part of GNU Inetutils.
GNU Inetutils is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
GNU Inetutils 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see `http://www.gnu.org/licenses/'. */
/* Written by Mats Erik Andersson. */
/* Addrpeek is a test client for examining Inetd, primarily TCP traffic.
* The client executes all those tasks that were listed as server
* arguments in the configuration file for Inetd:
*
* addr : Reply with "Your address is $IP."
* env : Reply with all known environment variables and their values.
*
* Reasonable entries in `inetf.conf' could be
*
* # Return numerical address of the calling client.
* #
* 7890 stream tcp nowait nobody /tmp/addrpeek addrpeek addr
* 7890 stream tcp6 nowait nobody /tmp/addrpeek addrpeek addr
* #
* # Display all environment variables in use, and append
* # the client's address at the end.
* #
* tcpmux stream tcp nowait nobody internal
* tcpmux stream tcp6 nowait nobody internal
* tcpmux/env stream tcp nowait nobody /tmp/addrpeek addrkeep env addr
*/
#include <config.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <progname.h>
#ifndef SEPARATOR
# define SEPARATOR "\n"
#endif
static void
write_address (int fd)
{
int type;
size_t len;
socklen_t sslen;
char addr[INET6_ADDRSTRLEN], answer[128];
struct sockaddr_storage ss;
sslen = sizeof (type);
getsockopt (fd, SOL_SOCKET, SO_TYPE, &type, &sslen);
if (type == SOCK_STREAM)
{
sslen = sizeof (ss);
getpeername (fd, (struct sockaddr *) &ss, &sslen);
}
else if (type == SOCK_DGRAM)
{
sslen = sizeof (ss);
recvfrom (fd, answer, sizeof (answer), 0,
(struct sockaddr *) &ss, &sslen);
shutdown (fd, SHUT_RD);
}
else
return;
getnameinfo ((struct sockaddr *) &ss, sslen, addr, sizeof (addr),
NULL, 0, NI_NUMERICHOST);
len = snprintf (answer, sizeof (answer),
"Your address is %s." SEPARATOR, addr);
sendto (fd, answer, len, 0, (struct sockaddr *) &ss, sslen);
}
void
write_environment (int fd, char *envp[])
{
for (; *envp; ++envp)
{
write (fd, *envp, strlen (*envp));
write (fd, SEPARATOR, strlen (SEPARATOR));
}
}
int
main (int argc, char *argv[])
{
int j;
set_program_name (argv[0]);
for (j = 1; j < argc; ++j)
{
if (strncmp (argv[j], "addr", strlen ("addr")) == 0)
{
write_address (STDOUT_FILENO);
continue;
}
if (strncmp (argv[j], "env", strlen ("env")) == 0)
{
write_environment (STDOUT_FILENO, environ);
continue;
}
}
close (STDIN_FILENO);
close (STDOUT_FILENO);
close (STDERR_FILENO);
return EXIT_SUCCESS;
}
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