Improved ui socket and made open and create send requests.

Two new issues to solve:

* Should the ui communication component also be the one that manages
  permissions?
* The format of data sent (protocol) needs definition.

Makefile

@@ -22,7 +22,7 @@ endif
 SOURCES_DIR := ./sources
 BUILD_DIR := ./build
 
-build: $(BUILD_DIR)/main.o $(BUILD_DIR)/sourcefs.o
+build: $(BUILD_DIR)/main.o $(BUILD_DIR)/sourcefs.o $(BUILD_DIR)/ui-socket.o
 	$(CC) $(CFLAGS) $^ $(LDFLAGS) -o $(BUILD_DIR)/icfs
 
 $(BUILD_DIR)/main.o: $(SOURCES_DIR)/main.c
@@ -31,5 +31,8 @@ $(BUILD_DIR)/main.o: $(SOURCES_DIR)/main.c
 $(BUILD_DIR)/sourcefs.o: $(SOURCES_DIR)/sourcefs.c $(SOURCES_DIR)/sourcefs.h
 	$(CC) $(CFLAGS) -c $< $(LDFLAGS) -o $@
 
+$(BUILD_DIR)/ui-socket.o: $(SOURCES_DIR)/ui-socket.c $(SOURCES_DIR)/ui-socket.h
+	$(CC) $(CFLAGS) -c $< $(LDFLAGS) -o $@
+
 clean:
 	rm $(BUILD_DIR)/*

sources/main.c

@@ -49,6 +49,7 @@
 #include <sys/file.h> /* flock(2) */
 
 #include "sourcefs.h"
+#include "ui-socket.h"
 
 const char *mountpoint = NULL;
 
@@ -360,6 +361,16 @@ static int xmp_create(const char *path, mode_t mode,
                       struct fuse_file_info *fi) {
   int fd;
 
+  struct process_info pi;
+
+  struct fuse_context *fc = fuse_get_context();
+
+  pi.PID = fc->pid;
+  pi.UID = fc->uid;
+  pi.name = "";
+
+  printf("%d", ask_access(path, pi));
+
   fd = source_create(path, fi->flags, mode);
   if (fd == -1)
     return -errno;
@@ -371,6 +382,16 @@ static int xmp_create(const char *path, mode_t mode,
 static int xmp_open(const char *path, struct fuse_file_info *fi) {
   int fd;
 
+  struct process_info pi;
+
+  struct fuse_context *fc = fuse_get_context();
+
+  pi.PID = fc->pid;
+  pi.UID = fc->uid;
+  pi.name = "";
+
+  printf("%d", ask_access(path, pi));
+
   fd = source_open(path, fi->flags);
   if (fd == -1)
     return -errno;
@@ -663,7 +684,13 @@ int main(int argc, char *argv[]) {
 
   int ret = source_init(mountpoint);
   if (ret != 0) {
-    perror("Failed to initialize filesystem.");
+    perror("source_init");
+    exit(EXIT_FAILURE);
+  }
+
+  ret = init_ui_socket("/home/fedir/.icfs-sock");
+  if (ret != 0) {
+    perror("init_ui_socket");
     exit(EXIT_FAILURE);
   }
 

sources/ui-socket.c

@@ -0,0 +1,116 @@
+#define _GNU_SOURCE
+#include "ui-socket.h"
+#include <errno.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#define MAX_MESSAGE_SIZE 1024
+
+// Mutex for thread safety
+static pthread_mutex_t socket_mutex = PTHREAD_MUTEX_INITIALIZER;
+static int ui_socket_fd = -1; // Global socket file descriptor
+
+int init_ui_socket(const char *filename) {
+  if (!filename) {
+    return -1;
+  }
+
+  // Create the socket
+  ui_socket_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+  if (ui_socket_fd == -1) {
+    perror("socket");
+    return -1;
+  }
+
+  // Remove the socket file if it already exists
+  if (unlink(filename) == -1 &&
+      errno != ENOENT) { // ENOENT means the file does not exist, which is fine
+    perror("unlink");
+    close(ui_socket_fd);
+    ui_socket_fd = -1;
+    return -1;
+  }
+
+  // Set up the socket address structure
+  struct sockaddr_un addr;
+  memset(&addr, 0, sizeof(struct sockaddr_un));
+  addr.sun_family = AF_UNIX;
+  strncpy(addr.sun_path, filename, sizeof(addr.sun_path) - 1);
+
+  // Bind the socket
+  if (bind(ui_socket_fd, (struct sockaddr *)&addr,
+           sizeof(struct sockaddr_un)) == -1) {
+    perror("bind");
+    close(ui_socket_fd);
+    ui_socket_fd = -1;
+    return -1;
+  }
+
+  // Listen for incoming connections
+  if (listen(ui_socket_fd, 5) == -1) {
+    perror("listen");
+    close(ui_socket_fd);
+    ui_socket_fd = -1;
+    return -1;
+  }
+
+  return 0;
+}
+
+int ask_access(const char *filename, struct process_info pi) {
+  if (!filename || ui_socket_fd == -1) {
+    return -1;
+  }
+
+  // Lock the mutex for thread safety
+  pthread_mutex_lock(&socket_mutex);
+
+  int client_fd = accept(ui_socket_fd, NULL, NULL);
+  if (client_fd == -1) {
+    perror("accept");
+    pthread_mutex_unlock(&socket_mutex);
+    return -1;
+  }
+
+  // Prepare the message to send to the GUI
+  char message[MAX_MESSAGE_SIZE];
+  int len_filename = strlen(filename);
+  int len_name = strlen(pi.name);
+
+  snprintf(message, sizeof(message), "r%04d%s%04d%04d%s%04d", len_filename,
+           filename, pi.PID, len_name, pi.name, pi.UID);
+
+  // Send the message to the GUI
+  if (send(client_fd, message, strlen(message), 0) == -1) {
+    perror("send");
+    close(client_fd);
+    pthread_mutex_unlock(&socket_mutex);
+    return -1;
+  }
+
+  // Receive the response from the GUI
+  char response[2];
+  if (recv(client_fd, response, sizeof(response), 0) == -1) {
+    perror("recv");
+    close(client_fd);
+    pthread_mutex_unlock(&socket_mutex);
+    return -1;
+  }
+
+  close(client_fd);
+  pthread_mutex_unlock(&socket_mutex);
+
+  // Process the response
+  if (response[0] == 'a' && response[1] == 'y') {
+    return 0; // Access granted
+  } else if (response[0] == 'a' && response[1] == 'n') {
+    return 1; // Access denied
+  }
+
+  return -1; // Invalid response
+}

sources/ui-socket.h

@@ -0,0 +1,24 @@
+
+/*
+ * Interface for controlling communication with the UI.
+ */
+
+#ifndef UI_SOCKET_H
+#define UI_SOCKET_H
+
+#include <sys/types.h>
+
+struct process_info {
+  pid_t PID;
+  const char *name;
+  uid_t UID;
+};
+
+// For default socket location, set socket_path = NULL.
+int init_ui_socket(const char *socket_path);
+
+// TODO: design an interface for asking user for permission.
+
+int ask_access(const char *filename, struct process_info pi);
+
+#endif // !UI_SOCKET_H