Add support for audio devices

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 92 insertions, 0 deletions

diff --git a/libgamepad_find_sound_devices.c b/libgamepad_find_sound_devices.c
new file mode 100644
index 0000000..1688106
--- /dev/null
+++ b/libgamepad_find_sound_devices.c
@@ -0,0 +1,92 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+static int
+search(int dirfd, const char *file, size_t **cardsp, size_t *countp, struct stat *st_buf)
+{
+	int fd;
+	DIR *dir;
+	struct dirent *f;
+	unsigned long num;
+	char *end;
+	void *new;
+
+	fd = openat(dirfd, file, O_DIRECTORY);
+	if (fd < 0)
+		return -1;
+	dir = fdopendir(fd);
+	if (!dir) {
+		close(fd);
+		return -1;
+	}
+
+	if (!strcmp(file, "sound")) {
+		while (errno = 0, (f = readdir(dir))) {
+			if (strncmp(f->d_name, "card", 4) || !isdigit(f->d_name[4]))
+				continue;
+			num = strtoul(&f->d_name[4], &end, 10);
+			if (errno || *end)
+				continue;
+			if (*countp == (size_t)SSIZE_MAX)
+				break;
+			new = realloc(*cardsp, (*countp + 1) * sizeof(**cardsp));
+			if (!new)
+				goto fail;
+			*cardsp = new;
+			(*cardsp)[(*countp)++] = (size_t)num;
+		}
+	} else {
+		while (errno = 0, (f = readdir(dir))) {
+			if (f->d_name[0] == '.')
+				continue;
+			if (fstatat(fd, f->d_name, st_buf, AT_SYMLINK_NOFOLLOW))
+				goto fail;
+			if (S_ISLNK(st_buf->st_mode))
+				continue;
+			search(fd, f->d_name, cardsp, countp, st_buf);
+		}
+	}
+
+	closedir(dir);
+	return errno ? -1 : 0;
+
+fail:
+	closedir(dir);
+	return -1;
+}
+
+
+ssize_t
+libgamepad_find_sound_devices(const char *syspath, size_t **cardsp)
+{
+	int fd, i, saved_errno = errno;
+	size_t count = 0;
+	struct stat st;
+	const char *p = syspath;
+
+	*cardsp = NULL;
+
+	if (*p != '/')
+		return 0;
+	for (i = 0; i < 5; i++) {
+		p = strchr(&p[1], '/');
+		if (!p)
+			return 0;
+	}
+
+	fd = open(syspath, O_DIRECTORY);
+	if (fd < 0)
+		return -1;
+
+	if (search(fd, "../..", cardsp, &count, &st)) {
+		close(fd);
+		free(*cardsp);
+		*cardsp = NULL;
+		return -1;
+	}
+
+	close(fd);
+	errno = saved_errno;
+	return (ssize_t)count;
+}