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;
 
@@ -217,6 +218,7 @@ static int xmp_releasedir(const char *path, struct fuse_file_info *fi) {
   return 0;
 }
 
+/*
 // TODO: make this work
 static int xmp_mknod(const char *path, mode_t mode, dev_t rdev) {
   int res;
@@ -230,6 +232,7 @@ static int xmp_mknod(const char *path, mode_t mode, dev_t rdev) {
 
   return 0;
 }
+*/
 
 static int xmp_mkdir(const char *path, mode_t mode) {
   int res;
@@ -288,7 +291,7 @@ static int xmp_rename(const char *from, const char *to, unsigned int flags) {
 static int xmp_link(const char *from, const char *to) {
   int res;
 
-  res = link(from, to);
+  res = source_link(from, to);
   if (res == -1)
     return -errno;
 
@@ -301,7 +304,7 @@ static int xmp_chmod(const char *path, mode_t mode, struct fuse_file_info *fi) {
   if (fi)
     res = fchmod(fi->fh, mode);
   else
-    res = chmod(path, mode);
+    res = source_chmod(path, mode);
   if (res == -1)
     return -errno;
 
@@ -315,7 +318,7 @@ static int xmp_chown(const char *path, uid_t uid, gid_t gid,
   if (fi)
     res = fchown(fi->fh, uid, gid);
   else
-    res = lchown(path, uid, gid);
+    res = source_chown(path, uid, gid);
   if (res == -1)
     return -errno;
 
@@ -329,7 +332,7 @@ static int xmp_truncate(const char *path, off_t size,
   if (fi)
     res = ftruncate(fi->fh, size);
   else
-    res = truncate(path, size);
+    res = source_truncate(path, size);
 
   if (res == -1)
     return -errno;
@@ -358,7 +361,17 @@ static int xmp_create(const char *path, mode_t mode,
                       struct fuse_file_info *fi) {
   int fd;
 
-  fd = open(path, fi->flags, mode);
+  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;
 
@@ -369,7 +382,17 @@ static int xmp_create(const char *path, mode_t mode,
 static int xmp_open(const char *path, struct fuse_file_info *fi) {
   int fd;
 
-  fd = open(path, fi->flags);
+  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;
 
@@ -386,6 +409,7 @@ static int xmp_open(const char *path, struct fuse_file_info *fi) {
   return 0;
 }
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_read(const char *path, char *buf, size_t size, off_t offset,
                     struct fuse_file_info *fi) {
   int res;
@@ -398,6 +422,7 @@ static int xmp_read(const char *path, char *buf, size_t size, off_t offset,
   return res;
 }
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_read_buf(const char *path, struct fuse_bufvec **bufp,
                         size_t size, off_t offset, struct fuse_file_info *fi) {
   struct fuse_bufvec *src;
@@ -419,6 +444,7 @@ static int xmp_read_buf(const char *path, struct fuse_bufvec **bufp,
   return 0;
 }
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_write(const char *path, const char *buf, size_t size,
                      off_t offset, struct fuse_file_info *fi) {
   int res;
@@ -431,6 +457,7 @@ static int xmp_write(const char *path, const char *buf, size_t size,
   return res;
 }
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_write_buf(const char *path, struct fuse_bufvec *buf,
                          off_t offset, struct fuse_file_info *fi) {
   struct fuse_bufvec dst = FUSE_BUFVEC_INIT(fuse_buf_size(buf));
@@ -454,6 +481,7 @@ static int xmp_statfs(const char *path, struct statvfs *stbuf) {
   return 0;
 }
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_flush(const char *path, struct fuse_file_info *fi) {
   int res;
 
@@ -470,6 +498,7 @@ static int xmp_flush(const char *path, struct fuse_file_info *fi) {
   return 0;
 }
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_release(const char *path, struct fuse_file_info *fi) {
   (void)path;
   close(fi->fh);
@@ -477,6 +506,7 @@ static int xmp_release(const char *path, struct fuse_file_info *fi) {
   return 0;
 }
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_fsync(const char *path, int isdatasync,
                      struct fuse_file_info *fi) {
   int res;
@@ -551,6 +581,7 @@ static int xmp_lock(const char *path, struct fuse_file_info *fi, int cmd,
 }
 #endif
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static int xmp_flock(const char *path, struct fuse_file_info *fi, int op) {
   int res;
   (void)path;
@@ -580,6 +611,7 @@ static ssize_t xmp_copy_file_range(const char *path_in,
 }
 #endif
 
+/* Complete copy of the example method(no need to modify anything so far) */
 static off_t xmp_lseek(const char *path, off_t off, int whence,
                        struct fuse_file_info *fi) {
   off_t res;
@@ -592,15 +624,16 @@ static off_t xmp_lseek(const char *path, off_t off, int whence,
   return res;
 }
 
+// TODO: look trough "optional"(commented out) operations.
 static const struct fuse_operations xmp_oper = {
     .init = xmp_init,
     .getattr = xmp_getattr,
-    .access = xmp_access,
+    // .access = xmp_access,
     .readlink = xmp_readlink,
     .opendir = xmp_opendir,
     .readdir = xmp_readdir,
     .releasedir = xmp_releasedir,
-    .mknod = xmp_mknod,
+    //    .mknod = xmp_mknod,
     .mkdir = xmp_mkdir,
     .symlink = xmp_symlink,
     .unlink = xmp_unlink,
@@ -611,7 +644,7 @@ static const struct fuse_operations xmp_oper = {
     .chown = xmp_chown,
     .truncate = xmp_truncate,
 #ifdef HAVE_UTIMENSAT
-    .utimens = xmp_utimens,
+// .utimens = xmp_utimens,
 #endif
     .create = xmp_create,
     .open = xmp_open,
@@ -624,20 +657,20 @@ static const struct fuse_operations xmp_oper = {
     .release = xmp_release,
     .fsync = xmp_fsync,
 #ifdef HAVE_POSIX_FALLOCATE
-    .fallocate = xmp_fallocate,
+// .fallocate = xmp_fallocate,
 #endif
 #ifdef HAVE_SETXATTR
-    .setxattr = xmp_setxattr,
-    .getxattr = xmp_getxattr,
-    .listxattr = xmp_listxattr,
-    .removexattr = xmp_removexattr,
+// .setxattr = xmp_setxattr,
+// .getxattr = xmp_getxattr,
+// .listxattr = xmp_listxattr,
+// .removexattr = xmp_removexattr,
 #endif
 #ifdef HAVE_LIBULOCKMGR
-    .lock = xmp_lock,
+// .lock = xmp_lock,
 #endif
     .flock = xmp_flock,
 #ifdef HAVE_COPY_FILE_RANGE
-    .copy_file_range = xmp_copy_file_range,
+// .copy_file_range = xmp_copy_file_range,
 #endif
     .lseek = xmp_lseek,
 };
@@ -651,7 +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/sourcefs.c

@@ -70,6 +70,47 @@ DIR *source_opendir(const char *filename) {
 }
 
 int source_rename(const char *oldpath, const char *newpath) {
-  printf("{\"%s\", \"%s\"}\n", oldpath, newpath);
-  return -1;
+  const char *relative_oldpath = source_fname_translate(oldpath);
+  const char *relative_newpath = source_fname_translate(newpath);
+  return renameat(handle.root_fd, relative_oldpath, handle.root_fd,
+                  relative_newpath);
+}
+
+int source_link(const char *oldpath, const char *newpath) {
+  const char *relative_oldpath = source_fname_translate(oldpath);
+  const char *relative_newpath = source_fname_translate(newpath);
+  return linkat(handle.root_fd, relative_oldpath, handle.root_fd,
+                relative_newpath, 0);
+  // NOTE: perhaps the flags here need to be reevaluated.
+}
+
+int source_chmod(const char *filename, mode_t mode) {
+  const char *relative_filename = source_fname_translate(filename);
+  return fchmodat(handle.root_fd, relative_filename, mode, 0);
+  // NOTE: perhaps the flags here need to be reevaluated.
+}
+
+int source_chown(const char *filename, uid_t owner, gid_t group) {
+  const char *relative_filename = source_fname_translate(filename);
+  return fchownat(handle.root_fd, filename, owner, group, AT_SYMLINK_NOFOLLOW);
+}
+
+int source_truncate(const char *filename, off_t length) {
+  const char *relative_filename = source_fname_translate(filename);
+  int fd = openat(handle.root_fd, relative_filename, NULL);
+  if (fd < 0) {
+    perror("Openat failed");
+    return -1;
+  }
+  return ftruncate(fd, length);
+}
+
+int source_open(const char *filename, int flags) {
+  const char *relative_filename = source_fname_translate(filename);
+  return openat(handle.root_fd, relative_filename, flags);
+}
+
+int source_create(const char *filename, int flags, mode_t mode) {
+  const char *relative_filename = source_fname_translate(filename);
+  return openat(handle.root_fd, relative_filename, flags, mode);
 }

sources/sourcefs.h

@@ -33,4 +33,19 @@ int source_symlink(const char *target, const char *linkpath);
 
 int source_rename(const char *oldpath, const char *newpath);
 
+int source_link(const char *oldpath, const char *newpath);
+
+int source_chmod(const char *filename, mode_t mode);
+
+int source_chown(const char *filename, uid_t owner, gid_t group);
+
+int source_truncate(const char *filename, off_t length);
+
+/* `open` and `create` are designed to correspond to fuse operations, not the
+ * libc's `open(2)`. Both of them actually call `openat`. */
+
+int source_open(const char *filename, int flags);
+
+int source_create(const char *filename, int flags, mode_t mode);
+
 #endif // !SOURCEFS_H

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