extFS-Seyshell/src/disk.c

/** @file */
#include "disk.h"
#include "struct.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

int init_inode_in_disk(disk *d, int inode_index, int filetype,
                       unsigned short perms, int owned_bloc) {
  if (d->inodes[inode_index].filetype != TYPE_NULL)
    return -1;

  d->owned_blocs[owned_bloc] = 1;

  d->inodes[inode_index].filetype = filetype;
  d->inodes[inode_index].perms = perms;

  for (int i = 0; i < MAX_BLOCS; i++) {
    d->inodes[inode_index].blocs[i] = -1;
  }
  d->inodes[inode_index].blocs[0] = owned_bloc;

  return 0;
}

int find_free_bloc(disk *d) {
  for (int i = 0; i < MAX_BLOCS; i++) {
    if (d->owned_blocs[i] == 0) {
      d->owned_blocs[i] = 1;
      return i;
    }
  }
  return -1;
}

int find_offset_in_parent_bloc(bloc *parent_bloc) {
  int entry_size = MAX_INODE_NAME + sizeof(int);
  int max_entries = MAX_BYTES_PER_BLOC / entry_size;

  for (int i = 0; i < max_entries; i++) {
    int current_offset = i * entry_size;
    // Si le premier caractère est '\0', la case est libre
    if (parent_bloc->datas[current_offset] == '\0') {
      return current_offset;
    }
  }
  return -1;
}

int create_directory(disk *disk, inode *parent, char *dirname) {}

int create_file(disk *disk, inode *parent, char *filename) {
  int inode_index = 0;
  while (inode_index < MAX_INODE &&
         disk->inodes[inode_index].filetype != TYPE_NULL) {
    inode_index++;
  }

  if (inode_index >= MAX_INODE) {
    dprintf(STDERR_FILENO, "No free inodes\n");
    return -1;
  }

  int new_bloc_idx = find_free_bloc(disk);
  if (new_bloc_idx == -1) {
    dprintf(STDERR_FILENO, "Disk Full\n");
    return -1;
  }

  int p_bloc_idx = parent->blocs[0];
  int offset = find_offset_in_parent_bloc(&disk->blocs[p_bloc_idx]);

  if (offset == -1) {
    dprintf(STDERR_FILENO, "Parent directory full\n");
    return -1;
  }

  strncpy(&disk->blocs[p_bloc_idx].datas[offset], filename, MAX_INODE_NAME);
  memcpy(&disk->blocs[p_bloc_idx].datas[offset + MAX_INODE_NAME], &inode_index,
         sizeof(int));

  init_inode_in_disk(disk, inode_index, TYPE_FILE, 0b111111111, new_bloc_idx);
  return inode_index;
}

int create_inode(disk *disk, inode *parent, char inode_type, char *name) {
  if (strlen(name) > MAX_INODE_NAME) {
    dprintf(STDERR_FILENO, "A inode name must be < %d\n", MAX_INODE_NAME);
    return -1;
  }
  if (parent->filetype != TYPE_DIRECTORY) {
    dprintf(STDERR_FILENO, "A parent's inode must be a directory!\n");
    return -1;
  }

  switch (inode_type) {
  case TYPE_DIRECTORY:
    return create_directory(disk, parent, name);
    break;
  case TYPE_FILE:
    return create_file(disk, parent, name);
  case TYPE_BINARY:
    // TODO plus tard
    break;
  case TYPE_SYMBOLIC_LINK:
    // TODO plus tard
    break;
  default:
    break;
  }
  return -1;
}

void write_in_file(disk *d, int file_index, char *data /*, char mode*/) {
  inode file = d->inodes[file_index];
  if (file.filetype != TYPE_FILE) {
    dprintf(STDERR_FILENO, "Can only write in files\n");
    return;
  }

  // mode 'w' (on écrase tout ^^)
  // les blocs sont possédés par un seul inode donc c'est ok de tout écraser
  // TODO: regarder si l'inode est sur plusieurs blocs et écraser tous les blocs
  // possédé

  int bloc_index_to_overwrite = file.blocs[0];
  if (bloc_index_to_overwrite == -1) {
    dprintf(STDERR_FILENO, "This inode does not have any bloc\n");
    return;
  }

  strncpy(&d->blocs[bloc_index_to_overwrite].datas[0], data, strlen(data));
}

void do_ls(disk *d, int dir_index) {
  inode dir = d->inodes[dir_index];
  if (dir.filetype != TYPE_DIRECTORY) {
    dprintf(STDERR_FILENO, "ls: Can only list in directories\n");
    return;
  }

  // TODO: chercher sur tous les blocs possédés
  int bloc = dir.blocs[0];

  for (int i = 0; i < MAX_BYTES_PER_BLOC; i += MAX_INODE_NAME + sizeof(int)) {
    if (d->blocs[bloc].datas[i] != '\0') {
      int inode_id;
      memcpy(&inode_id, &d->blocs[bloc].datas[i + MAX_INODE_NAME], sizeof(int));
      dprintf(STDOUT_FILENO, "%-16s %d\n", &d->blocs[bloc].datas[i], inode_id);
    }
  }
}

char *read_in_file(disk *d, int file_index) {
  inode file = d->inodes[file_index];
  if (file.filetype != TYPE_FILE) {
    dprintf(STDERR_FILENO, "Can only read in files\n");
    return NULL;
  }

  // TODO: chercher sur tous les blocs possédés
  int bloc = file.blocs[0];
  char *out;
  int c_index = 0;
  while (d->blocs[bloc].datas[c_index] != '\0' || c_index < MAX_BYTES_PER_BLOC) {
    c_index++;
  }

  out = malloc(c_index * sizeof(char));
  if (out == NULL) {
    dprintf(STDERR_FILENO, "Error while allocating with malloc\n");
    exit(EXIT_FAILURE);
  }

  strncpy(out, d->blocs[bloc].datas, c_index);

  return out;
}

void init_env_var_file(disk *d) {
  int inode_idx = create_inode(d, &d->inodes[0], TYPE_FILE, "env");
  write_in_file(d, inode_idx, "PWD=/\nUSER=user");
}

/**
 * @brief Créer un fichier "disk" de taille MAX_BYTES_PER_BLOC * MAX_BLOCS,
 * renvoi ce disque
 * @return Le disque créé
 */
disk create_disk() {
  FILE *fptr;
  fptr = fopen("disk", "wb");

  disk d;
  for (int i = 0; i < MAX_INODE; i++) {
    d.inodes[i].filetype = TYPE_NULL;
    d.inodes[i].perms = 0b000000000;
    for (int j = 0; j < MAX_BLOCS; j++) {
      d.inodes[i].blocs[j] = -1;
    }
  }

  for (int i = 0; i < MAX_BLOCS; i++) {
    d.owned_blocs[i] = 0;
  }

  // création de la racine '/'
  d.inodes[0].filetype = TYPE_DIRECTORY;
  d.inodes[0].perms = 0b111111111; // tlm fait ce qu'il veut
  d.inodes[0].blocs[0] = 0;        // utilise le bloc 0
  d.owned_blocs[0] = 1;            // le bloc 1 est maintenant occupé

  init_env_var_file(&d);

  int n = fwrite(&d, sizeof(disk), 1, fptr);
  if (n == 1) {
    dprintf(STDOUT_FILENO, "Disk of size %.2fKb created successfully.\n",
            (float)(MAX_BYTES_PER_BLOC * MAX_BLOCS) / 1000);
  }

  fclose(fptr);
  return d;
}

/**
 * @brief Si un fichier filename existe, alors on le lit et le stocke en mémoire
 * @param char *filename Le nom du fichier à lire
 * @return Le disque lu
 */
disk open_disk(char *filename) {
  disk d;
  FILE *fptr = fopen(filename, "r");
  if (fptr == NULL)
    exit(EXIT_FAILURE);
  fread(&d, sizeof(d), 1, fptr);
  fclose(fptr);
  return d;
}