X-Git-Url: https://gapil.gnulinux.it/gitweb/?p=gapil.git;a=blobdiff_plain;f=sources%2FTCP_echod.c;fp=sources%2FTCP_echod.c;h=606f85281c81117797816563483880e32814f43f;hp=0000000000000000000000000000000000000000;hb=d12bc3e1e4b3ee762036d1c226c3b2ba1a720fb9;hpb=e3e15ed6d698e5cc35f3b7f4c5db96adc38255c3 diff --git a/sources/TCP_echod.c b/sources/TCP_echod.c new file mode 100644 index 0000000..606f852 --- /dev/null +++ b/sources/TCP_echod.c @@ -0,0 +1,204 @@ +/* ElemEchoTCPServer.c + * + * Copyright (C) 2001 Simone Piccardi + * + * This program 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 2 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 + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ +/**************************************************************** + * + * Program echod + * Elementary TCP server for echo service (port 7) + * + * Author: Simone Piccardi + * Jun. 2001 + * + * Usage: echod -h give all info + * + * $Id: TCP_echod.c,v 1.1 2003/05/02 09:50:55 piccardi Exp $ + * + ****************************************************************/ +/* + * Include needed headers + */ +#include /* predefined types */ +#include /* include unix standard library */ +#include /* IP addresses conversion utiliites */ +#include /* socket library */ +#include /* include standard I/O library */ +#include +#include /* syslog system functions */ +#include /* signal functions */ +#include "Gapil.h" + +#define BACKLOG 10 +#define MAXLINE 256 +int demonize = 1; /* daemon use option */ +int debugging = 0; /* debug info printing option */ +/* Subroutines declaration */ +void usage(void); +void ServEcho(int sockfd); +void PrintErr(char * error); +/* Program beginning */ +int main(int argc, char *argv[]) +{ +/* + * Variables definition + */ + int list_fd, conn_fd; + pid_t pid; + struct sockaddr_in serv_add; + /* + * Input section: decode parameters passed in the calling + * Use getopt function + */ + int i; + opterr = 0; /* don't want writing to stderr */ + while ( (i = getopt(argc, argv, "hdi")) != -1) { + switch (i) { + /* + * Handling options + */ + case 'h': + printf("Wrong -h option use\n"); + usage(); + return(0); + break; + case 'i': + demonize = 0; + break; + case 'd': + debugging = 1; + break; + case '?': /* unrecognized options */ + printf("Unrecognized options -%c\n",optopt); + usage(); + default: /* should not reached */ + usage(); + } + } + /* *********************************************************** + * + * Options processing completed + * + * Main code beginning + * + * ***********************************************************/ + /* install SIGCHLD handler */ + Signal(SIGCHLD, HandSigCHLD); /* establish handler */ + /* create socket */ + if ( (list_fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) { + perror("Socket creation error"); + exit(1); + } + /* initialize address */ + memset((void *)&serv_add, 0, sizeof(serv_add)); /* clear server address */ + serv_add.sin_family = AF_INET; /* address type is INET */ + serv_add.sin_port = htons(7); /* echo port is 7 */ + serv_add.sin_addr.s_addr = htonl(INADDR_ANY); /* connect from anywhere */ + /* bind socket */ + if (bind(list_fd, (struct sockaddr *)&serv_add, sizeof(serv_add)) < 0) { + perror("bind error"); + exit(1); + } + /* release privileges and go daemon */ + if (setgid(65534) !=0) { /* first give away group privileges */ + perror("cannot give away group privileges"); + exit(1); + } + if (setuid(65534) !=0) { /* and only after user ... */ + perror("cannot give away user privileges"); + exit(1); + } + if (demonize) { /* go daemon */ + openlog(argv[0], 0, LOG_DAEMON); /* open logging */ + if (daemon(0, 0) != 0) { + perror("cannot start as daemon"); + exit(1); + } + } + /* main body */ + if (listen(list_fd, BACKLOG) < 0 ) { + PrintErr("listen error"); + exit(1); + } + /* handle echo to client */ + while (1) { + /* accept connection */ + if ( (conn_fd = accept(list_fd, NULL, NULL)) < 0) { + PrintErr("accept error"); + exit(1); + } + /* fork to handle connection */ + if ( (pid = fork()) < 0 ){ + PrintErr("fork error"); + exit(1); + } + if (pid == 0) { /* child */ + close(list_fd); /* close listening socket */ + ServEcho(conn_fd); /* handle echo */ + exit(0); + } else { /* parent */ + close(conn_fd); /* close connected socket */ + } + } + /* normal exit, never reached */ + exit(0); +} +/* + * routine to print usage info and exit + */ +void usage(void) { + printf("Elementary echo server\n"); + printf("Usage:\n"); + printf(" echod [-h] \n"); + printf(" -h print this help\n"); + printf(" -d print debug info\n"); + printf(" -i use interactively\n"); + exit(1); +} +/* + * routine to handle echo for connection + */ +void ServEcho(int sockfd) { + char buffer[MAXLINE]; + int nread, nwrite; + char debug[MAXLINE+20]; + int size; + /* main loop, reading 0 char means client close connection */ + while ( (nread = read(sockfd, buffer, MAXLINE)) != 0) { + nwrite = FullWrite(sockfd, buffer, nread); + if (debugging) { + buffer[nread] = 0; + snprintf(debug, MAXLINE+20, "Letti %d byte, %s", nread, buffer); + if (demonize) { /* go daemon */ + syslog(LOG_DEBUG, debug); + } else { + printf("%s", debug); + } + } + } + return; +} +/* + * routine to print error on stout or syslog + */ +void PrintErr(char * error) { + if (demonize) { /* go daemon */ + syslog(LOG_ERR, error); + } else { + perror(error); + } + return; +}