Read directory bug ?

[Userzxcvbvnm]

Describe the bug

Data/mydir is a directory, and there is a file Data/mydir/test.txt.

The c file is uploaded as
test-c.txt

The wasm file is uploaded as
test-wasm.txt

Steps to reproduce

Change Data/mydir into 0600 (rw- --- ---)
using command wasmer run --dir=./Data test.wasm

Expected behavior

Print:

.
..
test.txt

wamr，wasmedge and native (gcc test.c -o test and ./test) print this message.

Actual behavior

Print:

Enter fd_readdir.
opendir: Permission denied

Additional context

Ubuntu 20.04 (x86_64)
wasmer v4.2.2

[Michael-F-Bryan]

This looks like it might be an issue with how you are mapping directories because --dir ./Data will mount the directory to one location, while the WASI app's current directory is set to /.

Can you try mounting ./Data with --mapdir /data:./Data and updating your code to iterate over /data/mydir? We tried running with --dir ./Data just then and it errored out saying you need to use an absolute path, so maybe also try running --dir $(pwd)/Data and update the paths in your code accordingly?

---

For context, this is the contents of test-c.txt:

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <sys/stat.h>
#include <fcntl.h>


int fd_readdir(const char *path) {
    printf("Enter fd_readdir.\n");

    DIR *directory;
    struct dirent *entry;

    directory = opendir(path);

    if (directory == NULL) {
        perror("opendir");
        return 1;
    }

    while ((entry = readdir(directory)) != NULL) {
        printf("%s\n", entry->d_name);
    }

    closedir(directory);
    printf("Leave fd_readdir.\n");
    return 0;
}


int main() {
    const char *dirPath = "Data/mydir";
    fd_readdir(dirPath);
    return 0;
}

[Userzxcvbvnm]

Thanks for your reply! We tried to execute it in two ways:
(1)Modify the C file code into :

const char *dirPath = "data/mydir";

and using command wasmer run --mapdir /data:./Data test.wasm
It prints:

Enter fd_readdir.
opendir: Operation not permitted

(2)Modify the C file code into :

const char *dirPath = "$(pwd)/Data/mydir";

and using command wasmer run --dir=$(pwd)/Data test.wasm
It prints:

Enter fd_readdir.
opendir: Operation not permitted

And the permission of mydir is changed into 0600 before execution, just as we mentioned initially.
Maybe it is related to permission?