init

.gitignore

@@ -0,0 +1,4 @@
+test
+compile_commands.json
+.vscode
+.cache

Makefile

@@ -0,0 +1,48 @@
+# Compiler and flags
+CPPC = gcc
+COMMON_CPPC_FLAGS = -Wall -Wextra -lm
+CPPC_FLAGS = $(COMMON_CPPC_FLAGS) -s -O3
+DEBUG_FLAGS = $(COMMON_CPPC_FLAGS) -ggdb
+DEBUG_ASANITIZE = $(DEBUG_FLAGS) -fsanitize=address -fno-omit-frame-pointer
+
+
+SRC_PATH := src
+OBJ_PATH := build/obj
+BIN_PATH := build/bin
+BIN_NAME := pupes-backup-server
+
+
+SRC_FILES := $(shell find $(SRC_PATH) -name '*.c')
+OBJ_FILES := $(patsubst $(SRC_PATH)/%.c,$(OBJ_PATH)/%.o,$(SRC_FILES))
+
+
+all: make-build-dir $(BIN_PATH)/$(BIN_NAME)
+
+
+debug: CPPC_FLAGS = $(DEBUG_FLAGS)
+debug: make-build-dir $(BIN_PATH)/$(BIN_NAME)
+
+asan: CPPC_FLAGS = $(DEBUG_ASANITIZE)
+asan: make-build-dir $(BIN_PATH)/$(BIN_NAME)
+
+
+make-build-dir:
+	mkdir -p $(OBJ_PATH)
+	mkdir -p $(BIN_PATH)
+
+
+$(BIN_PATH)/$(BIN_NAME): $(OBJ_FILES)
+	$(CPPC) $(CPPC_FLAGS) $^ -o $@
+
+
+$(OBJ_PATH)/%.o: $(SRC_PATH)/%.c
+	$(CPPC) $(CPPC_FLAGS) -c $< -o $@
+
+
+install:
+	@install -vpm 755 -o root -g root $(BIN_PATH)/$(BIN_NAME) /usr/bin/
+
+clean:
+	rm -fr build
+
+.PHONY: all clean install debug asan

src/color.h

@@ -0,0 +1,22 @@
+// Header guard
+#ifndef RESET
+
+#define RESET   "\033[0m"
+#define BLACK   "\033[30m"      /* Black */
+#define RED     "\033[31m"      /* Red */
+#define GREEN   "\033[32m"      /* Green */
+#define YELLOW  "\033[33m"      /* Yellow */
+#define BLUE    "\033[34m"      /* Blue */
+#define MAGENTA "\033[35m"      /* Magenta */
+#define CYAN    "\033[36m"      /* Cyan */
+#define WHITE   "\033[37m"      /* White */
+#define BOLDBLACK   "\033[1m\033[30m"      /* Bold Black */
+#define BOLDRED     "\033[1m\033[31m"      /* Bold Red */
+#define BOLDGREEN   "\033[1m\033[32m"      /* Bold Green */
+#define BOLDYELLOW  "\033[1m\033[33m"      /* Bold Yellow */
+#define BOLDBLUE    "\033[1m\033[34m"      /* Bold Blue */
+#define BOLDMAGENTA "\033[1m\033[35m"      /* Bold Magenta */
+#define BOLDCYAN    "\033[1m\033[36m"      /* Bold Cyan */
+#define BOLDWHITE   "\033[1m\033[37m"      /* Bold White */
+
+#endif

src/main.c

@@ -0,0 +1,138 @@
+#include <asm-generic/errno-base.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <math.h>
+#include <fcntl.h>
+#include <sys/sendfile.h>
+#include "color.h"
+
+#define ALLOWED_IP "192.168.1.213"
+#define MAX_FILE_SIZE_G 100
+#define MAX_FILE_SIZE (size_t)MAX_FILE_SIZE_G*1073741824
+
+#define READ_BUFFER_SIZE 32768 // 256K
+
+const char* filename_base = "backup";
+
+int sockfd;
+
+int main(int argc, char* argv[]) {
+    if (argc < 2) {
+        fprintf(stderr, "Usage:\n%s [BACKUP DIRECTORY]\n", argv[0]);
+        return EINVAL;
+    }
+    int client_fd;
+    struct sockaddr_in servaddr, client_addr;
+    socklen_t client_len = sizeof(client_addr);
+    
+    sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sockfd == -1) {
+        perror("socket creation failed");
+        exit(EXIT_FAILURE);
+    }
+    printf("Socket created successfully\n");
+    
+    int opt = 1;
+    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) < 0) {
+        perror("setsockopt failed");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+    
+    memset(&servaddr, 0, sizeof(servaddr));
+    servaddr.sin_family = AF_INET;
+    servaddr.sin_addr.s_addr = INADDR_ANY;
+    servaddr.sin_port = htons(15531);
+    
+    if (bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0) {
+        perror("socket bind failed");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+    printf("Socket bound to port 15531\n");
+    
+    if (listen(sockfd, 1) != 0) {
+        perror("listen failed");
+        close(sockfd);
+        exit(EXIT_FAILURE);
+    }
+    printf("Listening on port 15531\n");
+    
+    while (1) {
+        client_fd = accept(sockfd, (struct sockaddr *)&client_addr, &client_len);
+        if (client_fd < 0) {
+            perror("accept failed");
+            continue;
+        }
+        
+        char client_ip[INET_ADDRSTRLEN];
+        inet_ntop(AF_INET, &(client_addr.sin_addr), client_ip, INET_ADDRSTRLEN);
+        
+        
+        if (strcmp(client_ip, ALLOWED_IP) == 0) {
+            printf("Accepted connection from %s\n", client_ip);
+            const time_t unix_time = time(NULL);
+
+            const uint8_t time_lenght = floor(log10(unix_time)) + 1;
+
+            const size_t path_with_filename_lenght = strlen(argv[1]) + 1 /*'/'*/ + strlen(filename_base) + 1 /*'-'*/ + time_lenght + 1 /*NULL BYTE*/;
+
+            char* full_filename_path = malloc(path_with_filename_lenght);
+            char* moved_ptr;
+            moved_ptr = stpcpy(full_filename_path,argv[1]); //copy directory path
+            moved_ptr[0] = '/';
+            moved_ptr = stpcpy(&moved_ptr[1], filename_base);
+            moved_ptr[0] = '-';
+            sprintf(&moved_ptr[1], "%lu", unix_time); // time + NULL terminator
+
+            int savefile_fd = open(full_filename_path, O_WRONLY | O_CREAT, 0644);
+
+            ssize_t bytes_transferred;
+            size_t receved_this_read_cicle = SIZE_MAX;
+            size_t total_received = 0;
+            char* read_buffer = malloc(READ_BUFFER_SIZE);
+            while (receved_this_read_cicle != 0 && total_received < MAX_FILE_SIZE){
+            receved_this_read_cicle = 0;
+            while ((bytes_transferred = read(client_fd, read_buffer, READ_BUFFER_SIZE - receved_this_read_cicle)) > 0) {
+                if (bytes_transferred == -1) {
+                    fprintf(stderr, YELLOW"["RED"CRITICAL"YELLOW"]"RESET" Error: %s, when receving file: %s failed file may be corupted\n", strerror(errno) ,full_filename_path);
+                    goto client_cleanup;
+                }
+                receved_this_read_cicle += bytes_transferred;
+            }
+            if (receved_this_read_cicle == 0) {break;}
+            
+            total_received += receved_this_read_cicle;
+            
+            if (write(savefile_fd, read_buffer, receved_this_read_cicle) == -1) {
+                fprintf(stderr, YELLOW"["RED"CRITICAL"YELLOW"]"RESET" Error: %s, when writing file: %s failed file may be corupted\n", strerror(errno) ,full_filename_path);
+            }}
+            client_cleanup:
+
+            printf("finished handling: %s\n",full_filename_path);
+            free(read_buffer);
+            free(full_filename_path);
+            close(savefile_fd);
+            close(client_fd);
+        } else {
+            printf("Rejected connection from %s\n", client_ip);
+            close(client_fd);
+        }
+    }
+    return 0;
+}
+
+[[gnu::destructor]]
+void program_exit() {
+    shutdown(sockfd, SHUT_RDWR);
+    close(sockfd);
+}