From ab2d7fd8bfb1eafc61953e74757e84ed407b1f21 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Sun, 15 Sep 2019 17:34:39 +0200
Subject: Add an sqfs_file_t implementation for reading from STDIN

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
 lib/sqfs/io_stdin.c | 115 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 lib/sqfs/io_stdin.c

(limited to 'lib/sqfs/io_stdin.c')

diff --git a/lib/sqfs/io_stdin.c b/lib/sqfs/io_stdin.c
new file mode 100644
index 0000000..a65fa0f
--- /dev/null
+++ b/lib/sqfs/io_stdin.c
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * io_stdin.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 <errno.h>
+
+
+typedef struct {
+	sqfs_file_t base;
+
+	uint64_t offset;
+	uint64_t size;
+} sqfs_file_stdin_t;
+
+
+static void stdin_destroy(sqfs_file_t *base)
+{
+	free(base);
+}
+
+static int stdin_read_at(sqfs_file_t *base, uint64_t offset,
+			 void *buffer, size_t size)
+{
+	sqfs_file_stdin_t *file = (sqfs_file_stdin_t *)base;
+	size_t temp_size = 0;
+	uint8_t *temp = NULL;
+	uint64_t diff;
+	ssize_t ret;
+
+	if (offset < file->offset)
+		return SQFS_ERROR_IO;
+
+	if (offset > file->offset) {
+		temp_size = 1024;
+		temp = alloca(temp_size);
+	}
+
+	if (offset >= file->size || (offset + size) > file->size)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	while (size > 0) {
+		if (offset > file->offset) {
+			diff = file->offset - offset;
+			diff = diff > (uint64_t)temp_size ? temp_size : diff;
+
+			ret = read(STDIN_FILENO, temp, diff);
+		} else {
+			ret = read(STDIN_FILENO, buffer, size);
+		}
+
+		if (ret < 0) {
+			if (errno == EINTR)
+				continue;
+			return SQFS_ERROR_IO;
+		}
+
+		if (ret == 0)
+			return SQFS_ERROR_OUT_OF_BOUNDS;
+
+		if (offset <= file->offset) {
+			buffer = (char *)buffer + ret;
+			size -= ret;
+			offset += ret;
+		}
+
+		file->offset += ret;
+	}
+
+	return 0;
+}
+
+static int stdin_write_at(sqfs_file_t *base, uint64_t offset,
+			  const void *buffer, size_t size)
+{
+	(void)base; (void)offset; (void)buffer; (void)size;
+	return SQFS_ERROR_IO;
+}
+
+static uint64_t stdin_get_size(const sqfs_file_t *base)
+{
+	return ((const sqfs_file_stdin_t *)base)->size;
+}
+
+static int stdin_truncate(sqfs_file_t *base, uint64_t size)
+{
+	(void)base; (void)size;
+	return SQFS_ERROR_IO;
+}
+
+sqfs_file_t *sqfs_get_stdin_file(uint64_t size)
+{
+	sqfs_file_stdin_t *file = calloc(1, sizeof(*file));
+	sqfs_file_t *base = (sqfs_file_t *)file;
+
+	if (file == NULL)
+		return NULL;
+
+	file->size = size;
+	base->destroy = stdin_destroy;
+	base->read_at = stdin_read_at;
+	base->write_at = stdin_write_at;
+	base->get_size = stdin_get_size;
+	base->truncate = stdin_truncate;
+	return base;
+}
-- 
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