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/*
* This file is in the public domain. If this is not possible in your region,
* please refer to the UNLICENSE which should be included with the software.
* Author: Ben Fuller
* Upstream: https://git.bvnf.space/bnetkit/
*
* Basic netcat-like utility to create a connection on the specified
* address and port, using stdin and stdout.
*
*/
#include <stdio.h>
#include <errno.h>
#include <poll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#define BUF_LEN 1024
int sock_write(int sfd, char *msg, size_t len);
int sock_read(int sfd);
int server_connect(char *argv0, char *nodename, char *servname) {
int sfd = -1;
struct addrinfo hints, *result, *rp;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
hints.ai_protocol = 0;
int s = getaddrinfo(nodename, servname, &hints, &result);
if (s != 0) {
fprintf(stderr, "%s: getaddrinfo: %s\n", argv0, gai_strerror(s));
return -1;
}
for (rp = result; rp != NULL; rp = rp->ai_next) {
sfd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (sfd == -1)
continue;
if (connect(sfd, rp->ai_addr, rp->ai_addrlen) == 0)
break;
if (close(sfd) == -1) {
perror("close");
freeaddrinfo(result);
return -1;
}
}
freeaddrinfo(result);
if (rp == NULL) {
fprintf(stderr, "%s: %s:%s: connection refused\n", argv0, nodename, servname);
return -1;
}
return sfd;
}
int main(int argc, char **argv) {
int timeout = 5 * 1000; /* 5 seconds */
if (argc < 3) {
fprintf(stderr, "usage: %s host port\n", argv[0]);
return 1;
}
int sfd = server_connect(argv[0], argv[1], argv[2]);
if (sfd == -1)
return 1;
int pollret;
struct pollfd fds[2];
fds[0].fd = 0;
fds[0].events = POLLIN;
fds[1].fd = sfd;
fds[1].events = POLLIN;
char *line = NULL;
size_t linelen = 0;
while (1) {
fds[0].revents = 0;
fds[1].revents = 0;
errno = 0;
pollret = poll(fds, 2, timeout);
if (pollret < 0) {
if (errno == EAGAIN)
continue;
perror("poll");
free(line);
return 1;
} else if (pollret == 0) {
/* timeout */
fprintf(stderr, "%s: %s:%s: timeout\r\n", argv[0], argv[1], argv[2]);
free(line);
return 1;
}
if (fds[0].revents) {
ssize_t n = getline(&line, &linelen, stdin);
if (n == -1) {
/* send EOF to server */
if (shutdown(sfd, SHUT_WR) == -1)
perror("shutdown");
/* prevent poll from checking stdin all the time */
fds[0].fd = -1;
continue;
}
if (sock_write(sfd, line, (size_t)n) != 0) {
free(line);
return 1;
}
}
if (fds[1].revents) {
int rec = sock_read(sfd);
if (rec < 0) {
free(line);
return 1;
} else if (rec == 0) {
/* received EOF */
break;
}
}
}
free(line);
if (close(sfd) == -1) {
perror("close");
return 1;
}
return 0;
}
int sock_write(int sfd, char *msg, size_t len) {
ssize_t ret = send(sfd, msg, len, 0);
if (ret != (ssize_t) len) {
perror("sock_write");
return 1;
}
return 0;
}
int sock_read(int sfd) {
char buff[BUF_LEN] = {'\0'};
ssize_t ret = recv(sfd, buff, BUF_LEN, 0);
if (ret < 0) {
perror("sock_read");
return -1;
}
if (ret == 0)
return 0;
write(1, buff, ret);
return 1;
}
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