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#include <arpa/inet.h>
#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
void usage(char *program_name) {
fprintf(stderr, "Usage: %s host port program [arg...]\n", program_name);
}
int main(int argc, char **argv) {
if (argc < 4) {
usage(*argv);
return 1;
}
char *host = *(argv + 1);
if ('-' == *host) {
fprintf(stderr, "Sorry, command line arguments are not supported\n");
return 1;
}
char *port = *(argv + 2);
char *program = *(argv + 3);
// The arguments beign at argv + 4 but
// argv[0] should be "program" anyways.
char **program_arguments = argv + 3;
int port_number = atoi(port);
if (0 == port_number) {
fprintf(stderr, "Invalid port: %s\n", port);
return 1;
}
int sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (-1 == sockfd) {
perror("socket");
return 1;
}
struct sockaddr_in servaddr;
memset(&servaddr, 0, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(port_number);
if (-1 == bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr))) {
perror("bind");
return 1;
}
for (;;) {
struct sockaddr_in cli;
socklen_t len = sizeof(cli);
int connfd = accept(sockfd, (struct sockaddr *)&cli, &len);
if (-1 == connfd) {
perror("accept");
continue;
}
if (0 == fork()) {
dup2(connfd, 0);
dup2(connfd, 1);
assert(-1 == execv(program, program_arguments));
perror("execv");
return 1;
}
close(connfd);
}
close(sockfd);
return 0;
}
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