/*
** fd/xnu.cpp
**  - provides support for XNU (part of Darwin)
*/
#include "animia/fd/xnu.h"
#include "animia.h"

#include <unordered_map>
#include <vector>
#include <string>
#include <cassert>

#include <fcntl.h>
#include <sys/sysctl.h>
#include <sys/types.h>
#include <sys/user.h>
#include <libproc.h>

namespace animia::internal::xnu {

static std::string GetProcessName(pid_t pid) {
	struct proc_bsdinfo proc;

	int st = proc_pidinfo(pid, PROC_PIDTBSDINFO, 0, &proc, PROC_PIDTBSDINFO_SIZE);
	if (st != PROC_PIDTBSDINFO_SIZE)
		return "";

	/* fixme: is this right? pbi_comm is an alternative, but it reduces the string size to
	   16 chars. does pbi_name do the same, or is it different? */
	return proc.pbi_name;
}

/* this is a cleaned up version of a function from... Apple?
   ...anyway, what it essentially does is gets the size and stuff from
   sysctl() and reserves the space in a vector to store the PIDs */
bool XnuFdTools::EnumerateOpenProcesses(process_proc_t process_proc) {
	struct kinfo_proc* result = NULL;
	size_t length = 0;
	static const int name[] = {CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0};

	/* get appropriate length from sysctl()
	   note: the reason this isn't checked is actually because this will
	   *always* return an error on OS X (or... maybe I'm doing it wrong :) ) */
	sysctl((int*)name, (sizeof(name) / sizeof(*name)) - 1, NULL, &length, NULL, 0);

	result = (struct kinfo_proc*)malloc(length);
	if (result == NULL)
		return false;

	/* TODO: this might actually return ENOMEM if the amount of file handles changes between the
	   original sysctl() call and this one, which is technically possible */
	if (sysctl((int*)name, (sizeof(name) / sizeof(*name)) - 1, result, &length, NULL, 0) == ENOMEM) {
		assert(result != NULL);
		free(result);
		return false;
	}

	for (int i = 0; i < length / sizeof(*result); i++) {
		const pid_t pid = result[i].kp_proc.p_pid;
		if (!process_proc({pid, GetProcessName(pid)}))
			return false;
	}

	return true;
}

bool XnuFdTools::EnumerateOpenFiles(const std::set<pid_t>& pids, open_file_proc_t open_file_proc) {
	if (!open_file_proc)
		return false;

	for (const auto& pid : pids) {
		int bufsz = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, NULL, 0);
		if (bufsz == -1)
			return false;

		struct proc_fdinfo* info = (struct proc_fdinfo*)malloc(bufsz);
		if (!info)
			return false;

		proc_pidinfo(pid, PROC_PIDLISTFDS, 0, info, bufsz);

		for (int i = 0; i < bufsz / sizeof(info[0]); i++) {
			if (info[i].proc_fdtype == PROX_FDTYPE_VNODE) {
				struct vnode_fdinfowithpath vnodeInfo;

				int sz = proc_pidfdinfo(pid, info[i].proc_fd, PROC_PIDFDVNODEPATHINFO, &vnodeInfo, PROC_PIDFDVNODEPATHINFO_SIZE);
				if (sz != PROC_PIDFDVNODEPATHINFO_SIZE)
					return false;

				/* this doesn't work!
				if (vnodeInfo.pfi.fi_openflags & O_WRONLY || vnodeInfo.pfi.fi_openflags & O_RDWR)
					continue;
				*/

				if (!open_file_proc({pid, vnodeInfo.pvip.vip_path}))
					return false;
			}
		}
	}

	return true;
}

} // namespace animia::internal::unix