Small lib to mock chroot() for pacman in Arch Linux running under WSL.

libmockchroot.c

// gcc libmockchroot.c -shared -fPIC -ldl -o /lib64/libmockchroot.so
// echo "/lib64/libmockchroot.so" >> /etc/ld.so.preload

#define _GNU_SOURCE
#include <unistd.h>
#include <libgen.h>
#include <dlfcn.h>
#include <linux/limits.h>
#include <string.h>

int chroot(const char *path)
{
	// return 0 for pacman

	char dest[PATH_MAX];
	if (readlink("/proc/self/exe", dest, PATH_MAX) != -1) {
		char* file = basename(dest);
		if (strcmp(file, "pacman") == 0) {
			return 0;
		}
	}

	// passthrough for others,
	// currently results in -1 and errno=38

	int (*_chroot)(const char*);
	_chroot = dlsym(RTLD_NEXT, "chroot");
	return (*_chroot)(path);
}