path: root/libgamepad_list_superdevices.c

/* See LICENSE file for copyright and license details. */
#include "common.h"


int
libgamepad_list_superdevices(char ***devicesp, size_t *ndevicesp)
{
	char path[PATH_MAX], target[PATH_MAX]; /* TODO do not use PATH_MAX */
	int dirfd;
	DIR *dir;
	struct dirent *f;
	ssize_t r;
	char **paths = NULL;
	size_t n = 0, i;
	void *new;
	int saved_errno = errno;

	*devicesp = NULL;
	*ndevicesp = 0;

	dirfd = open("/sys/class/input/", O_DIRECTORY);
	if (dirfd < 0)
		return -1;

	dir = fdopendir(dirfd);
	if (!dir) {
		close(dirfd);
		return -1;
	}

	while (errno = 0, (f = readdir(dir))) {
		if (!strncmp(f->d_name, "event", 5) && isdigit(f->d_name[5])) {
			stpcpy(stpcpy(stpcpy(path, "/sys/class/input/"), f->d_name), "/device/device");
			dirfd = open(path, O_PATH);
			if (dirfd < 0)
				continue;
			sprintf(path, "/dev/fd/%i", dirfd);
			r = readlink(path, target, sizeof(target) - 1);
			close(dirfd);
			if (r < 0)
				continue;
			target[r] = '\0';
			if (paths)
				for (i = 0; i < n; i++)
					if (!strcmp(paths[i], target))
						goto next;
			stpcpy(stpcpy(path, target), "/input");
			if (access(path, F_OK))
				continue;
			new = realloc(paths, (n + 1) * sizeof(*paths));
			if (!new)
				goto fail;
			paths = new;
			paths[n] = strdup(target);
			if (!paths[n])
				goto fail;
			n += 1;
		}
	next:;
	}

	if (errno)
		goto fail;
	closedir(dir);

	errno = saved_errno;
	*devicesp = paths;
	*ndevicesp = n;
	return 0;

fail:
	for (i = 0; i < n; i++)
		free(paths[i]);
	free(paths);
	closedir(dir);
	return -1;
}