Upon calling readdir function in a C program within an arm32-based container executing on x64-based Ubuntu 19.10 host, the call returns EOVERFLOW for empty directories (e.g., /mnt, /media) instead of returning 0.
Have others observed this issue? Is this a configuration issue? If so, how can it be fixed?
Versions:
- Guest: debian:buster- backports@sha256:8f27850df2144df1598b5c76b213616ecaab08e804a6d84ddace1455d8cbd9f0
- Host: Ubuntu 19.10, amd64, Docker version: 19.03.6-0ubuntu1~19.10.1
- Qemu version: 1:4.0+dfsg-0ubuntu9.6
Repro steps:
- Build an image named crystal-for-buster-armhf:v1 based on Debian Buster for arm32 using the Dockerfile and build.sh script available here.
- Start a container based on this image.
- Compile and build the below program.
- Execute the resulting executable with a directory name as a command line argument.
#define _POSIX_SOURCE
#include <dirent.h>
#include <errno.h>
#include <sys/types.h>
#undef _POSIX_SOURCE
#include <stdio.h>
main(int argc, char* argv[]) {
DIR *dir;
struct dirent *entry;
if ((dir = opendir(argv[1])) == NULL)
perror("opendir() error");
else {
puts("contents:");
while (1) {
errno = 0;
entry = readdir(dir);
if (entry == NULL) {
printf("Errno: %d EOVERFLOW: %d\n", errno, EOVERFLOW);
break;
}
printf(" %s\n", entry->d_name);
}
closedir(dir);
}
}