From 484cd01590ec488cca1f8a5c7c76cd223609e299 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Thu, 15 Jun 2023 15:16:03 +0200
Subject: Migrate file istream/ostream from libio to libsquashfs

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
 lib/sqfs/src/unix/ostream.c | 205 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 205 insertions(+)
 create mode 100644 lib/sqfs/src/unix/ostream.c

(limited to 'lib/sqfs/src/unix/ostream.c')

diff --git a/lib/sqfs/src/unix/ostream.c b/lib/sqfs/src/unix/ostream.c
new file mode 100644
index 0000000..89982c1
--- /dev/null
+++ b/lib/sqfs/src/unix/ostream.c
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * ostream.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "sqfs/io.h"
+#include "sqfs/error.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+
+typedef struct {
+	sqfs_ostream_t base;
+	char *path;
+	int flags;
+	int fd;
+
+	off_t sparse_count;
+	off_t size;
+} file_ostream_t;
+
+static int write_all(file_ostream_t *file, const sqfs_u8 *data, size_t size)
+{
+	while (size > 0) {
+		ssize_t ret = write(file->fd, data, size);
+
+		if (ret == 0) {
+			errno = EPIPE;
+			return SQFS_ERROR_IO;
+		}
+
+		if (ret < 0) {
+			if (errno == EINTR)
+				continue;
+			return SQFS_ERROR_IO;
+		}
+
+		file->size += ret;
+		size -= ret;
+		data += ret;
+	}
+
+	return 0;
+}
+
+static int realize_sparse(file_ostream_t *file)
+{
+	unsigned char *buffer;
+	size_t diff, bufsz;
+	int ret;
+
+	if (file->sparse_count == 0)
+		return 0;
+
+	if (file->flags & SQFS_FILE_OPEN_NO_SPARSE) {
+		bufsz = file->sparse_count > 1024 ? 1024 : file->sparse_count;
+		buffer = calloc(1, bufsz);
+		if (buffer == NULL)
+			return SQFS_ERROR_ALLOC;
+
+		while (file->sparse_count > 0) {
+			diff = file->sparse_count > (off_t)bufsz ?
+				bufsz : (size_t)file->sparse_count;
+
+			ret = write_all(file, buffer, diff);
+			if (ret) {
+				int temp = errno;
+				free(buffer);
+				errno = temp;
+				return ret;
+			}
+
+			file->sparse_count -= diff;
+		}
+
+		free(buffer);
+	} else {
+		if (lseek(file->fd, file->sparse_count, SEEK_CUR) == (off_t)-1)
+			return SQFS_ERROR_IO;
+
+		if (ftruncate(file->fd, file->size) != 0)
+			return SQFS_ERROR_IO;
+
+		file->sparse_count = 0;
+	}
+
+	return 0;
+}
+
+static int file_append(sqfs_ostream_t *strm, const void *data, size_t size)
+{
+	file_ostream_t *file = (file_ostream_t *)strm;
+	int ret;
+
+	if (size == 0 || data == NULL) {
+		file->sparse_count += size;
+		file->size += size;
+		return 0;
+	}
+
+	ret = realize_sparse(file);
+	if (ret)
+		return ret;
+
+	return write_all(file, data, size);
+}
+
+static int file_flush(sqfs_ostream_t *strm)
+{
+	file_ostream_t *file = (file_ostream_t *)strm;
+	int ret;
+
+	ret = realize_sparse(file);
+	if (ret)
+		return ret;
+
+	if (fsync(file->fd) != 0) {
+		if (errno != EINVAL)
+			return SQFS_ERROR_IO;
+	}
+
+	return 0;
+}
+
+static void file_destroy(sqfs_object_t *obj)
+{
+	file_ostream_t *file = (file_ostream_t *)obj;
+
+	close(file->fd);
+	free(file->path);
+	free(file);
+}
+
+static const char *file_get_filename(sqfs_ostream_t *strm)
+{
+	return ((file_ostream_t *)strm)->path;
+}
+
+int sqfs_ostream_open_handle(sqfs_ostream_t **out, const char *path,
+			     sqfs_file_handle_t fd, int flags)
+{
+	file_ostream_t *file = calloc(1, sizeof(*file));
+	sqfs_ostream_t *strm = (sqfs_ostream_t *)file;
+
+	*out = NULL;
+	if (file == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	sqfs_object_init(file, file_destroy, NULL);
+
+	file->path = strdup(path);
+	if (file->path == NULL) {
+		int temp = errno;
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_ALLOC;
+	}
+
+	file->fd = dup(fd);
+	if (file->fd < 0) {
+		int temp = errno;
+		free(file->path);
+		free(file);
+		errno = temp;
+		return SQFS_ERROR_IO;
+	}
+
+	close(fd);
+
+	file->flags = flags;
+	strm->append = file_append;
+	strm->flush = file_flush;
+	strm->get_filename = file_get_filename;
+
+	*out = strm;
+	return 0;
+}
+
+int sqfs_ostream_open_file(sqfs_ostream_t **out, const char *path, int flags)
+{
+	sqfs_file_handle_t fd;
+	int ret;
+
+	*out = NULL;
+	ret = sqfs_open_native_file(&fd, path, flags);
+	if (ret)
+		return ret;
+
+	ret = sqfs_ostream_open_handle(out, path, fd, flags);
+	if (ret) {
+		int temp = errno;
+		close(fd);
+		errno = temp;
+		return ret;
+	}
+
+	return 0;
+}
-- 
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