initial commit

4 files changed, 280 insertions, 0 deletions

diff --git a/src/auth.c b/src/auth.c
new file mode 100644
index 0000000..55fe083
--- /dev/null
+++ b/src/auth.c
@@ -0,0 +1,68 @@
+#include "netcosm.h"
+
+/* add a user to the on-disk database */
+
+/*
+ * format:
+ *  [login]:[hash]\n
+*/
+
+void add_user(const char *name, const char *pass)
+{
+    int fd = open(USERFILE, O_WRONLY | O_CREAT | O_APPEND, 0600);
+
+    int hash_len = gcry_md_get_algo_dlen(GCRY_MD_SHA512);
+    unsigned char *hash = malloc(hash_len);
+    gcry_md_hash_buffer(GCRY_MD_SHA512, hash, pass, strlen(pass));
+    char *hex = malloc(hash_len * 2 + 1);
+    char *ptr = hex;
+    for(int i = 0; i < hash_len; ++i, ++ptr)
+        snprintf(ptr, 3, "%02x", hash[i]);
+
+    flock(fd, LOCK_EX);
+
+    dprintf(fd, "%s:%s\n", name, hex);
+
+    flock(fd, LOCK_UN);
+}
+
+bool valid_login_name(const char *name)
+{
+    while(*name)
+    {
+        char c = *name++;
+        switch(c)
+        {
+        case ':':
+            return false;
+        default:
+            break;
+        }
+    }
+    return true;
+}
+
+void first_run_setup(void)
+{
+    printf("Welcome to NetCosm!\n");
+    printf("Please set up the administrator account now.\n");
+
+    char *admin_name;
+    size_t len = 0;
+    do {
+        admin_name = NULL;
+        printf("Admin account name: ");
+        fflush(stdout);
+        getline(&admin_name, &len, stdin);
+    } while(!valid_login_name(admin_name));
+
+    printf("Admin password (DO NOT USE A VALUABLE PASSWORD): ");
+    fflush(stdout);
+    char *admin_pass = NULL;
+    len = 0;
+    getline(&admin_pass, &len, stdin);
+
+    /* hash and store */
+
+    add_user(admin_name, admin_pass);
+}
diff --git a/src/client.c b/src/client.c
new file mode 100644
index 0000000..e907172
--- /dev/null
+++ b/src/client.c
@@ -0,0 +1,47 @@
+#include "netcosm.h"
+
+int client_fd;
+
+void __attribute__((format(printf,1,2))) out(const char *fmt, ...)
+{
+    char buf[128];
+    memset(buf, 0, sizeof(buf));
+    va_list ap;
+    va_start(ap, fmt);
+    vsnprintf(buf, sizeof(buf), fmt, ap);
+    va_end(ap);
+    write(client_fd, buf, sizeof(buf));
+}
+
+char *client_read(void)
+{
+    static char buf[128];
+    if(read(client_fd, buf, sizeof(buf) - 1) < 0)
+    {
+        error("lost connection");
+        exit(EXIT_FAILURE);
+    }
+    buf[sizeof(buf) - 1] = '\0';
+    const unsigned char ctrlc[] = { 0xff, 0xf4, 0xff, 0xfd, 0x06 };
+
+    if(!memcmp(buf, ctrlc, sizeof(ctrlc)))
+        exit(0);
+
+    return buf;
+}
+
+void client_main(int fd, struct sockaddr_in *addr, int total)
+{
+    client_fd = fd;
+
+    bool admin = false;
+
+    char *ip = inet_ntoa(addr->sin_addr);
+    printf("New client %s\n", ip);
+    printf("Total clients: %d\n", total);
+    out("Hello %s.\n", ip);
+    out("Please authenticate to continue.\n");
+    out("login: ");
+    char *input = client_read();
+
+}
diff --git a/src/netcosm.h b/src/netcosm.h
new file mode 100644
index 0000000..e8a1384
--- /dev/null
+++ b/src/netcosm.h
@@ -0,0 +1,23 @@
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <gcrypt.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/file.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define USERFILE "users.dat"
+
+void client_main(int fd, struct sockaddr_in *addr, int);
+void __attribute__((noreturn)) error(const char *fmt, ...);
+void first_run_setup(void);
diff --git a/src/server.c b/src/server.c
new file mode 100644
index 0000000..e727d19
--- /dev/null
+++ b/src/server.c
@@ -0,0 +1,142 @@
+/*
+ *   NetCosm - a MUD server
+ *   Copyright (C) 2015 Franklin Wei
+ *
+ *   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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "netcosm.h"
+
+#define PORT 1234
+#define BACKLOG 16
+
+void __attribute__((noreturn)) error(const char *fmt, ...)
+{
+    char buf[128];
+    memset(buf, 0, sizeof(buf));
+    va_list ap;
+    va_start(ap, fmt);
+    vsnprintf(buf, sizeof(buf), fmt, ap);
+    va_end(ap);
+    perror(buf);
+    exit(EXIT_FAILURE);
+}
+
+void sigchld_handler(int s)
+{
+    // waitpid() might overwrite errno, so we save and restore it:
+    int saved_errno = errno;
+
+    while(waitpid(-1, NULL, WNOHANG) > 0);
+
+    errno = saved_errno;
+}
+
+int port;
+
+void handle_client(int fd, struct sockaddr_in *addr, int num_clients)
+{
+    client_main(fd, addr, num_clients);
+}
+
+int server_socket;
+
+void serv_cleanup(void)
+{
+    printf("Shutdown server.\n");
+    if(shutdown(server_socket, SHUT_RDWR) > 0)
+        error("shutdown");
+    close(server_socket);
+}
+
+void sigint_handler(int sig)
+{
+    serv_cleanup();
+}
+
+int main(int argc, char *argv[])
+{
+    port = PORT;
+    int sock = socket(AF_INET, SOCK_STREAM, 0);
+
+    if(sock<0)
+        error("socket");
+
+    int tmp = 1;
+
+    if(setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &tmp, sizeof tmp) < 0)
+        error("setsockopt");
+
+    struct sockaddr_in addr;
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(port);
+
+    addr.sin_addr.s_addr = htonl(INADDR_ANY);
+
+    if(bind(sock, (struct sockaddr*) &addr, sizeof addr) < 0)
+        error("bind");
+
+    if(listen(sock, BACKLOG) < 0)
+        error("listen");
+
+    server_socket = sock;
+
+    struct sigaction sa;
+
+    sa.sa_handler = sigchld_handler; // reap all dead processes
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = SA_RESTART;
+    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
+        perror("sigaction");
+        exit(1);
+    }
+
+    signal(SIGINT, sigint_handler);
+
+    int num_clients = 0;
+
+    if(access(USERFILE, F_OK) < 0)
+        first_run_setup();
+
+    printf("Listening on port %d\n", port);
+
+    while(1)
+    {
+        struct sockaddr_in client;
+        socklen_t client_len;
+        int new_sock = accept(sock, (struct sockaddr*) &client, &client_len);
+        if(new_sock < 0)
+            error("accept");
+
+        pid_t pid = fork();
+        if(pid < 0)
+            error("fork");
+        if(!pid)
+        {
+            close(sock);
+
+            server_socket = new_sock;
+
+            ++num_clients;
+
+            handle_client(new_sock, &client, num_clients);
+
+            --num_clients;
+
+            exit(0);
+        }
+        else
+            close(new_sock);
+    }
+}