Attempted Inode-based VFS (Basic)

// https://stackoverflow.com/questions/78986903/fuse3-inability-to-create-inode-based-virtual-file-system

#define FUSE_USE_VERSION 31
#include <fuse3/fuse.h>
#include <stdio.h>
#include <string.h>
#include <dirent.h>
#include <errno.h>

static void *xmp_init(struct fuse_conn_info *conn, struct fuse_config *cfg) {
    // From passthrough example
    cfg->use_ino          = 1;
    cfg->entry_timeout    = 0;
    cfg->attr_timeout     = 0;
    cfg->negative_timeout = 0;

    // // From hello.c example
    // cfg->kernel_cache = 1;

    // cfg->readdir_ino =  1;
    // cfg->remember    = -1;


    return NULL;
}

static int xmp_getattr(const char *path, struct stat *stbuf, struct fuse_file_info *fi) {
    (void) fi;
    int res;

    // NOTE: Why it doesn't read the inode of "/hello.txt" ???
    // (it prints ERROR for that file too if you `ls`)
    // the only thing I want, is to read the inode, nothing more.
    res = lstat(path, stbuf);
    if (res == -1){
        printf("\033[91mERROR: getattr %lu %s\033[0m\n", stbuf->st_ino, path); // stbuf->st_ino just in case it returns -1 but fills the inode
        return -errno;
    }

    printf("getattr %lu = %s\n", stbuf->st_ino, path);

    return 0;
}

static int xmp_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi, enum fuse_readdir_flags flags) {
    if (strcmp(path, "/") != 0)
        return -ENOENT;

    printf("readdir: %s\n", path );
    filler(buf, ".", NULL, 0, 0);
    filler(buf, "..", NULL, 0, 0);

    struct stat st;
    memset(&st, 0, sizeof(st));
    st.st_ino = 5; // NOTE: WHY INODE IS NOT SET ???????
    st.st_mode = S_IFREG | 0444;
    filler(buf, "hello.txt", &st, 0, 0); // maybe use "..., FUSE_FILL_DIR_PLUS);"


    // // passthrough.c
    // DIR *dp;
    // struct dirent *de;

    // (void) offset;
    // (void) fi;
    // (void) flags;

    // dp = opendir(path);
    // if (dp == NULL)
    //  return -errno;
    //
    // while ((de = readdir(dp)) != NULL) {
    //  b++;
    //  struct stat st;
    //  memset(&st, 0, sizeof(st));
    //  st.st_ino = de->d_ino;
    //  st.st_mode = de->d_type << 12;
    //  // printf("%lu : %lu = %s\n", de->d_ino, b, de->d_name );
    //  char buf[100];
    //  snprintf(buf, 100, "name_%lu", b);
    //  if (filler(buf, buf, &st, 0, 0))
    //      break;
    // }

    // closedir(dp);

    return 0;
}

static struct fuse_operations xmp_oper = {
    .init     = xmp_init,
    .getattr    = xmp_getattr,
    .readdir    = xmp_readdir,
};

int main(int argc, char *argv[]) {
    // umask(0);
    return fuse_main(argc, argv, &xmp_oper, NULL);
}