git ssb

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/* echosrv: a simple line echo server with optional prefix adding.
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 *
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 * echsrv --listen localhost6:1234 --prefix "ssl: "
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 *
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 * This will bind to 1234, and echo every line pre-pending "ssl: ". This is
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 * used for testing: we create several such servers with different prefixes,
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 * then we connect test clients that can then check they get the proper data
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 * back (thus testing that shoveling works both ways) with the correct prefix
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 * (thus testing it connected to the expected service).
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 * **/
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#define _GNU_SOURCE
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#include <sys/types.h>
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <signal.h>
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#include <sys/socket.h>
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#include <sys/wait.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <pwd.h>
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#include <syslog.h>
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#include <libgen.h>
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#include <getopt.h>
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#include "common.h"
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/* Added to make the code compilable under CYGWIN 
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 * */
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#ifndef SA_NOCLDWAIT
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#define SA_NOCLDWAIT 0
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#endif
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const char* USAGE_STRING =
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"echosrv\n" \
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"usage:\n" \
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"\techosrv  [-v] --listen <address:port> [--prefix <prefix>]\n"
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"-v: verbose\n" \
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"--listen: address to listen on. Can be specified multiple times.\n" \
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"--prefix: add specified prefix before every line echoed.\n"
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"";
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const char* server_type = "echsrv"; /* keep setup_syslog happy */
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/* 
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 * Settings that depend on the command line. 
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 */
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char* prefix = "";
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int port;
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void parse_cmdline(int argc, char* argv[])
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{
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    int c;
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    struct option options[] = {
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        { "verbose",    no_argument,            &verbose,       1 },
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        { "numeric",    no_argument,            &numeric,       1 },
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        { "listen",     required_argument,      0,              'l' },
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        { "prefix",     required_argument,      0,              'p' },
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    };
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    struct addrinfo **a;
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    while ((c = getopt_long_only(argc, argv, "l:p:", options, NULL)) != -1) {
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        if (c == 0) continue;
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        switch (c) {
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        case 'l':
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            /* find the end of the listen list */
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            for (a = &addr_listen; *a; a = &((*a)->ai_next));
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            /* append the specified addresses */
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            resolve_name(a, optarg);
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            break;
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        case 'p':
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            prefix = optarg;
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            break;
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        default:
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            fprintf(stderr, "%s", USAGE_STRING);
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            exit(2);
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        }
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    }
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    if (!addr_listen) {
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        fprintf(stderr, "No listening port specified\n");
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        exit(1);
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    }
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}
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void start_echo(int fd)
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{
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    fd_set fds;
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    int res;
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    char buffer[1 << 20];
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    char* ret;
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    FILE *socket;
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    FD_ZERO(&fds);
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    socket = fdopen(fd, "r+");
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    if (!socket) {
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        CHECK_RES_DIE(-1, "fdopen");
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    }
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    while (1) {
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        ret = fgets(buffer, sizeof(buffer), socket);
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        if (!ret) {
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            fprintf(stderr, "%s", strerror(ferror(socket)));
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            return;
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        }
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        res = fprintf(socket, "%s%s", prefix, buffer);
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        if (res < 0) {
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            fprintf(stderr, "%s", strerror(ferror(socket)));
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            return;
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        }
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        fflush(socket);
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    }
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}
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void main_loop(int listen_sockets[], int num_addr_listen)
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{
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    int in_socket, i;
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    for (i = 0; i < num_addr_listen; i++) {
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        if (!fork()) {
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            while (1)
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            {
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                in_socket = accept(listen_sockets[i], 0, 0);
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                if (verbose) fprintf(stderr, "accepted fd %d\n", in_socket);
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                if (!fork())
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                {
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                    close(listen_sockets[i]);
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                    start_echo(in_socket);
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                    exit(0);
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                }
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                close(in_socket);
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            }
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        }
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    }
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    wait(NULL);
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}
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int main(int argc, char *argv[])
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{
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   extern char *optarg;
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   extern int optind;
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   int num_addr_listen;
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   int *listen_sockets;
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   parse_cmdline(argc, argv);
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   num_addr_listen = start_listen_sockets(&listen_sockets, addr_listen);
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   main_loop(listen_sockets, num_addr_listen);
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   return 0;
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}
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