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#define _GNU_SOURCE
/* #define GIGI_DYNAMIC */
#include <asm-generic/socket.h>
#include <bits/types/FILE.h>
#include <netinet/in.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
enum {
MAXIMUM_COMMAND_LENGTH = 256,
MAXIMUM_DATA_SIZE = 512,
FINGER_PORT = 79,
MAXIMUM_CONNECTIONS = 5
};
#ifdef GIGI_DYNAMIC
/* This is a proof of concept. Please do not actually use `gigi_do`, as it is
* clearly susceptible to command injection. */
void gigi_do(int connection_file_descriptor, const char *arguments);
#else
void gigi_show(int connection_file_descriptor, const char *arguments);
#endif
int main(void) {
int server_socket_file_descriptor;
int client_socket_file_descriptor;
struct sockaddr_in server_address;
struct sockaddr_in client_address;
char client_message_buffer[MAXIMUM_COMMAND_LENGTH];
socklen_t client_address_length;
int reuse_address_option = 1;
ssize_t client_socket_bytes_read;
server_socket_file_descriptor = socket(AF_INET, SOCK_STREAM, 0);
if (server_socket_file_descriptor < 0) {
perror("error: could not create server socket\n");
return 1;
}
memset(&server_address, 0, sizeof(server_address));
server_address.sin_family = AF_INET;
server_address.sin_addr.s_addr = htonl(INADDR_ANY);
server_address.sin_port = htons(FINGER_PORT);
if (setsockopt(server_socket_file_descriptor, SOL_SOCKET, SO_REUSEADDR,
&reuse_address_option, sizeof(reuse_address_option)) < 0) {
perror("error: could not set server socket option\n");
return 1;
}
if (bind(server_socket_file_descriptor, (struct sockaddr *)&server_address,
sizeof(server_address)) < 0) {
perror("error: could not bind server socket\n");
return 1;
}
if (listen(server_socket_file_descriptor, MAXIMUM_CONNECTIONS) < 0) {
perror("error: could not listen on server socket\n");
return 1;
}
client_address_length = sizeof(client_address);
for (;;) {
client_socket_file_descriptor =
accept(server_socket_file_descriptor,
(struct sockaddr *)&client_address, &client_address_length);
if (client_socket_file_descriptor < 0) {
perror("error: could not accept on client socket\n");
return 1;
}
memset(client_message_buffer, 0, sizeof(client_message_buffer));
client_socket_bytes_read =
read(client_socket_file_descriptor, client_message_buffer,
sizeof(client_message_buffer) - 1);
if (client_socket_bytes_read < 0) {
perror("error: could not read from client socket\n");
return 1;
}
client_message_buffer[client_socket_bytes_read] = '\0';
#ifdef GIGI_DYNAMIC
gigi_do(client_socket_file_descriptor, client_message_buffer);
#else
gigi_show(client_socket_file_descriptor, client_message_buffer);
#endif
if (close(client_socket_file_descriptor) < 0) {
perror("error: could not close client socket\n");
return 1;
}
}
/* if (close(server_socket_file_descriptor) < 0) {
perror("error: could not close server socket\n");
return 1;
}
return 0; */
}
#ifdef GIGI_DYNAMIC
void gigi_do(int connection_file_descriptor, const char *arguments) {
FILE *gigi_do_file;
char gigi_do_command[MAXIMUM_COMMAND_LENGTH];
char gigi_do_message[MAXIMUM_DATA_SIZE];
snprintf(gigi_do_command, MAXIMUM_COMMAND_LENGTH, "./.gigi/do %s", arguments);
gigi_do_file = (FILE *)popen(gigi_do_command, "r");
if (!gigi_do_file) {
perror("error: could not open gigi do file pipe\n");
return;
}
while (fgets(gigi_do_message, MAXIMUM_DATA_SIZE, gigi_do_file) != NULL) {
if (write(connection_file_descriptor, gigi_do_message,
strlen(gigi_do_message)) < 0) {
perror("error: could not write to client socket\n");
}
}
if (pclose(gigi_do_file) != 0) {
perror("error: could not close gigi do file pipe\n");
}
}
#endif
#ifndef GIGI_DYNAMIC
void gigi_show(int connection_file_descriptor, const char *arguments) {
FILE *gigi_show_file;
char gigi_show_message[MAXIMUM_DATA_SIZE];
gigi_show_file = fopen("./.gigi/show", "r");
if (arguments[0] != '\0') {
char gigi_show_command[MAXIMUM_COMMAND_LENGTH];
char gigi_show_arguments[MAXIMUM_COMMAND_LENGTH];
size_t gigi_show_arguments_index;
snprintf(gigi_show_arguments, MAXIMUM_COMMAND_LENGTH, "%s", arguments);
for (gigi_show_arguments_index = 0;
gigi_show_arguments_index < strlen(gigi_show_arguments);
++gigi_show_arguments_index) {
if (gigi_show_arguments[gigi_show_arguments_index] == '\n' ||
gigi_show_arguments[gigi_show_arguments_index] == '\r') {
gigi_show_arguments[gigi_show_arguments_index] = '\0';
}
}
if (gigi_show_arguments[0] == '\0') {
snprintf(gigi_show_arguments, MAXIMUM_COMMAND_LENGTH, "default");
}
snprintf(gigi_show_command, MAXIMUM_COMMAND_LENGTH, "./.gigi/%s",
gigi_show_arguments);
gigi_show_file = fopen(gigi_show_command, "r");
if (!gigi_show_file) {
fprintf(stderr, "error: could not open gigi show file: %s\n",
gigi_show_command);
gigi_show_file = fopen("./.gigi/default", "r");
}
if (!gigi_show_file) {
perror("error: could not open default gigi show file: default\n");
return;
}
printf("ok: %s\n", gigi_show_command);
}
while (fgets(gigi_show_message, MAXIMUM_DATA_SIZE, gigi_show_file) != NULL) {
if (write(connection_file_descriptor, gigi_show_message,
strlen(gigi_show_message)) < 0) {
perror("error: could not write to client socket\n");
}
}
if (fclose(gigi_show_file) != 0) {
perror("error: could not close gigi show file\n");
}
}
#endif
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