initial commit

poolbuf.h

@@ -0,0 +1,112 @@
+/*
+ * poolbuf - https://codeberg.org/sewn/drwl
+ * See LICENSE file for copyright and license details.
+ */
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <wayland-client.h>
+
+#include "drwl.h"
+
+typedef struct {
+    struct wl_buffer *wl_buf;
+    int32_t stride;
+    int32_t size;
+    void *data;
+} PoolBuf;
+
+#if defined(__linux__) || defined(___FreeBSD__)
+#ifdef __linux__
+#include <linux/memfd.h>
+#endif
+#define __POOLBUF_HAS_MEMFD_CREATE
+int memfd_create(const char *, unsigned);
+#else
+static void
+randname(char *buf)
+{
+	struct timespec ts;
+	clock_gettime(CLOCK_REALTIME, &ts);
+	long r = ts.tv_nsec;
+	for (int i = 0; i < 6; ++i) {
+		buf[i] = 'A'+(r&15)+(r&16)*2;
+		r >>= 5;
+	}
+}
+
+static int
+create_shm(void)
+{
+	char name[] = "/drwl-XXXXXX";
+	int retries = 100;
+
+	do {
+		randname(name + sizeof(name) - 7);
+		--retries;
+		int fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
+		if (fd >= 0) {
+			shm_unlink(name);
+			return fd;
+		}
+	} while (retries > 0 && errno == EEXIST);
+	return -1;
+}
+#endif
+
+/* Caller must call poolbuf_destroy after finalizing usage */
+static PoolBuf *
+poolbuf_create(struct wl_shm *shm, int32_t width, int32_t height)
+{
+	int fd;
+	void *data;
+	struct wl_shm_pool *shm_pool;
+	struct wl_buffer *wl_buf;
+	int32_t stride = drwl_stride(width);
+	int32_t size = stride * height;
+	PoolBuf *buf;
+
+#ifdef __POOLBUF_HAS_MEMFD_CREATE
+	fd = memfd_create("drwl-shm-buffer-pool",
+		MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_NOEXEC_SEAL);
+#else
+	fd = create_shm();
+#endif
+    if (fd < 0)
+		return NULL;
+
+	if ((ftruncate(fd, size)) < 0) {
+		close(fd);
+		return NULL;
+	}
+
+	data = mmap(NULL, size,
+			PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	if (data == MAP_FAILED) {
+		close(fd);
+		return NULL;
+	}
+
+	shm_pool = wl_shm_create_pool(shm, fd, size);
+	wl_buf = wl_shm_pool_create_buffer(shm_pool, 0,
+			width, height, stride, WL_SHM_FORMAT_ARGB8888);
+	wl_shm_pool_destroy(shm_pool);
+	close(fd);
+
+	buf = calloc(1, sizeof(PoolBuf));
+	buf->wl_buf = wl_buf;
+	buf->stride = stride;
+	buf->size = size;
+	buf->data = data;
+	return buf;
+}
+
+static void
+poolbuf_destroy(PoolBuf *buf)
+{
+	wl_buffer_destroy(buf->wl_buf);
+	munmap(buf->data, buf->size);
+	free(buf);
+}