ICFS/sources/sourcefs.c

#define _GNU_SOURCE

#include "sourcefs.h"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

static struct source_files_handle {
  int root_fd;
} handle;

const char *source_fname_translate(const char *filename) {
  if (strcmp("/", filename) == 0) {
    return ".";
  } else {
    return filename + 1;
  }
}

int source_init(const char *root_path) {
  int root_fd = open(root_path, O_PATH);

  if (root_fd == -1) {
    return -1;
  }

  handle.root_fd = root_fd;

  return 0;
}

int source_mkdir(const char *filename, mode_t mode) {
  const char *relative_filename = source_fname_translate(filename);
  return mkdirat(handle.root_fd, relative_filename, mode);
}

int source_unlink(const char *filename) {
  const char *relative_filename = source_fname_translate(filename);
  return unlinkat(handle.root_fd, relative_filename, 0);
}

int source_stat(const char *restrict filename, struct stat *restrict statbuf) {
  const char *relative_filename = source_fname_translate(filename);
  return fstatat(handle.root_fd, relative_filename, statbuf, 0);
}

int source_rmdir(const char *filename) {
  const char *relative_filename = source_fname_translate(filename);
  return unlinkat(handle.root_fd, relative_filename, AT_REMOVEDIR);
}

int source_symlink(const char *target, const char *linkpath) {
  const char *relative_linkpath = source_fname_translate(linkpath);
  return symlinkat(target, handle.root_fd, relative_linkpath);
}

DIR *source_opendir(const char *filename) {
  const char *relative_filename = source_fname_translate(filename);
  int fd = openat(handle.root_fd, relative_filename, NULL);
  if (fd < 0) {
    perror("Openat failed");
    return NULL;
  }
  DIR *dir_pointer = fdopendir(fd);
  return dir_pointer;
}

int source_rename(const char *oldpath, const char *newpath) {
  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);
}