fwupd/libfwupdplugin/fu-bytes.c

/*
 * Copyright (C) 2017 Richard Hughes <richard@hughsie.com>
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#define G_LOG_DOMAIN "FuCommon"

#include "config.h"

#ifdef HAVE_GIO_UNIX
#include <gio/gunixinputstream.h>
#endif

#include "fwupd-error.h"

#include "fu-bytes.h"
#include "fu-common.h"
#include "fu-mem.h"

/**
 * fu_bytes_set_contents:
 * @filename: a filename
 * @bytes: data to write
 * @error: (nullable): optional return location for an error
 *
 * Writes a blob of data to a filename, creating the parent directories as
 * required.
 *
 * Returns: %TRUE for success
 *
 * Since: 1.8.2
 **/
gboolean
fu_bytes_set_contents(const gchar *filename, GBytes *bytes, GError **error)
{
	const gchar *data;
	gsize size;
	g_autoptr(GFile) file = NULL;
	g_autoptr(GFile) file_parent = NULL;

	g_return_val_if_fail(filename != NULL, FALSE);
	g_return_val_if_fail(bytes != NULL, FALSE);
	g_return_val_if_fail(error == NULL || *error == NULL, FALSE);

	file = g_file_new_for_path(filename);
	file_parent = g_file_get_parent(file);
	if (!g_file_query_exists(file_parent, NULL)) {
		if (!g_file_make_directory_with_parents(file_parent, NULL, error))
			return FALSE;
	}
	data = g_bytes_get_data(bytes, &size);
	g_debug("writing %s with %" G_GSIZE_FORMAT " bytes", filename, size);
	return g_file_set_contents(filename, data, size, error);
}

/**
 * fu_bytes_get_contents:
 * @filename: a filename
 * @error: (nullable): optional return location for an error
 *
 * Reads a blob of data from a file.
 *
 * Returns: a #GBytes, or %NULL for failure
 *
 * Since: 1.8.2
 **/
GBytes *
fu_bytes_get_contents(const gchar *filename, GError **error)
{
	gchar *data = NULL;
	gsize len = 0;

	g_return_val_if_fail(filename != NULL, NULL);
	g_return_val_if_fail(error == NULL || *error == NULL, NULL);

	if (!g_file_get_contents(filename, &data, &len, error))
		return NULL;
	g_debug("reading %s with %" G_GSIZE_FORMAT " bytes", filename, len);
	return g_bytes_new_take(data, len);
}

/**
 * fu_bytes_get_contents_fd:
 * @fd: a file descriptor
 * @count: the maximum number of bytes to read
 * @error: (nullable): optional return location for an error
 *
 * Reads a blob from a specific file descriptor.
 *
 * Note: this will close the fd when done
 *
 * Returns: (transfer full): a #GBytes, or %NULL
 *
 * Since: 1.8.2
 **/
GBytes *
fu_bytes_get_contents_fd(gint fd, gsize count, GError **error)
{
#ifdef HAVE_GIO_UNIX
	g_autoptr(GInputStream) stream = NULL;

	g_return_val_if_fail(fd > 0, NULL);
	g_return_val_if_fail(error == NULL || *error == NULL, NULL);

	/* read the entire fd to a data blob */
	stream = g_unix_input_stream_new(fd, TRUE);
	return fu_bytes_get_contents_stream(stream, count, error);
#else
	g_set_error_literal(error,
			    FWUPD_ERROR,
			    FWUPD_ERROR_NOT_SUPPORTED,
			    "Not supported as <glib-unix.h> is unavailable");
	return NULL;
#endif
}

/**
 * fu_bytes_get_contents_stream:
 * @stream: input stream
 * @count: the maximum number of bytes to read
 * @error: (nullable): optional return location for an error
 *
 * Reads a blob from a specific input stream.
 *
 * Returns: (transfer full): a #GBytes, or %NULL
 *
 * Since: 1.8.2
 **/
GBytes *
fu_bytes_get_contents_stream(GInputStream *stream, gsize count, GError **error)
{
	guint8 tmp[0x8000] = {0x0};
	g_autoptr(GByteArray) buf = g_byte_array_new();
	g_autoptr(GError) error_local = NULL;

	g_return_val_if_fail(G_IS_INPUT_STREAM(stream), NULL);
	g_return_val_if_fail(error == NULL || *error == NULL, NULL);

	/* this is invalid */
	if (count == 0) {
		g_set_error_literal(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_NOT_SUPPORTED,
				    "A maximum read size must be specified");
		return NULL;
	}

	/* read from stream in 32kB chunks */
	while (TRUE) {
		gssize sz;
		sz = g_input_stream_read(stream, tmp, sizeof(tmp), NULL, &error_local);
		if (sz == 0)
			break;
		if (sz < 0) {
			g_set_error_literal(error,
					    FWUPD_ERROR,
					    FWUPD_ERROR_INVALID_FILE,
					    error_local->message);
			return NULL;
		}
		g_byte_array_append(buf, tmp, sz);
		if (buf->len > count) {
			g_set_error(error,
				    FWUPD_ERROR,
				    FWUPD_ERROR_INVALID_FILE,
				    "cannot read from fd: 0x%x > 0x%x",
				    buf->len,
				    (guint)count);
			return NULL;
		}
	}
	return g_byte_array_free_to_bytes(g_steal_pointer(&buf));
}

/**
 * fu_bytes_align:
 * @bytes: data blob
 * @blksz: block size in bytes
 * @padval: the byte used to pad the byte buffer
 *
 * Aligns a block of memory to @blksize using the @padval value; if
 * the block is already aligned then the original @bytes is returned.
 *
 * Returns: (transfer full): a #GBytes, possibly @bytes
 *
 * Since: 1.8.2
 **/
GBytes *
fu_bytes_align(GBytes *bytes, gsize blksz, gchar padval)
{
	const guint8 *data;
	gsize sz;

	g_return_val_if_fail(bytes != NULL, NULL);
	g_return_val_if_fail(blksz > 0, NULL);

	/* pad */
	data = g_bytes_get_data(bytes, &sz);
	if (sz % blksz != 0) {
		gsize sz_align = ((sz / blksz) + 1) * blksz;
		guint8 *data_align = g_malloc(sz_align);
		memcpy(data_align, data, sz);
		memset(data_align + sz, padval, sz_align - sz);
		g_debug("aligning 0x%x bytes to 0x%x", (guint)sz, (guint)sz_align);
		return g_bytes_new_take(data_align, sz_align);
	}

	/* perfectly aligned */
	return g_bytes_ref(bytes);
}

/**
 * fu_bytes_is_empty:
 * @bytes: data blob
 *
 * Checks if a byte array are just empty (0xff) bytes.
 *
 * Returns: %TRUE if @bytes is empty
 *
 * Since: 1.8.2
 **/
gboolean
fu_bytes_is_empty(GBytes *bytes)
{
	gsize sz = 0;
	const guint8 *buf = g_bytes_get_data(bytes, &sz);
	for (gsize i = 0; i < sz; i++) {
		if (buf[i] != 0xff)
			return FALSE;
	}
	return TRUE;
}

/**
 * fu_bytes_compare:
 * @bytes1: a data blob
 * @bytes2: another #GBytes
 * @error: (nullable): optional return location for an error
 *
 * Compares the buffers for equality.
 *
 * Returns: %TRUE if @bytes1 and @bytes2 are identical
 *
 * Since: 1.8.2
 **/
gboolean
fu_bytes_compare(GBytes *bytes1, GBytes *bytes2, GError **error)
{
	const guint8 *buf1;
	const guint8 *buf2;
	gsize bufsz1;
	gsize bufsz2;

	g_return_val_if_fail(bytes1 != NULL, FALSE);
	g_return_val_if_fail(bytes2 != NULL, FALSE);
	g_return_val_if_fail(error == NULL || *error == NULL, FALSE);

	buf1 = g_bytes_get_data(bytes1, &bufsz1);
	buf2 = g_bytes_get_data(bytes2, &bufsz2);
	return fu_memcmp_safe(buf1, bufsz1, buf2, bufsz2, error);
}

/**
 * fu_bytes_pad:
 * @bytes: data blob
 * @sz: the desired size in bytes
 *
 * Pads a GBytes to a minimum @sz with `0xff`.
 *
 * Returns: (transfer full): a data blob
 *
 * Since: 1.8.2
 **/
GBytes *
fu_bytes_pad(GBytes *bytes, gsize sz)
{
	gsize bytes_sz;

	g_return_val_if_fail(bytes != NULL, NULL);
	g_return_val_if_fail(sz != 0, NULL);

	/* pad */
	bytes_sz = g_bytes_get_size(bytes);
	if (bytes_sz < sz) {
		const guint8 *data = g_bytes_get_data(bytes, NULL);
		guint8 *data_new = g_malloc(sz);
		memcpy(data_new, data, bytes_sz);
		memset(data_new + bytes_sz, 0xff, sz - bytes_sz);
		return g_bytes_new_take(data_new, sz);
	}

	/* not required */
	return g_bytes_ref(bytes);
}

/**
 * fu_bytes_new_offset:
 * @bytes: data blob
 * @offset: where subsection starts at
 * @length: length of subsection
 * @error: (nullable): optional return location for an error
 *
 * Creates a #GBytes which is a subsection of another #GBytes.
 *
 * Returns: (transfer full): a #GBytes, or #NULL if range is invalid
 *
 * Since: 1.8.2
 **/
GBytes *
fu_bytes_new_offset(GBytes *bytes, gsize offset, gsize length, GError **error)
{
	g_return_val_if_fail(bytes != NULL, NULL);
	g_return_val_if_fail(error == NULL || *error == NULL, NULL);

	/* sanity check */
	if (offset + length > g_bytes_get_size(bytes)) {
		g_set_error(error,
			    G_IO_ERROR,
			    G_IO_ERROR_INVALID_DATA,
			    "cannot create bytes @0x%02x for 0x%02x "
			    "as buffer only 0x%04x bytes in size",
			    (guint)offset,
			    (guint)length,
			    (guint)g_bytes_get_size(bytes));
		return NULL;
	}
	return g_bytes_new_from_bytes(bytes, offset, length);
}

/**
 * fu_bytes_get_data_safe:
 * @bytes: data blob
 * @bufsz: (out) (optional): location to return size of byte data
 * @error: (nullable): optional return location for an error
 *
 * Get the byte data in the #GBytes. This data should not be modified.
 * This function will always return the same pointer for a given #GBytes.
 *
 * If the size of @bytes is zero, then %NULL is returned and the @error is set,
 * which differs in behavior to that of g_bytes_get_data().
 *
 * This may be useful when calling g_mapped_file_new() on a zero-length file.
 *
 * Returns: a pointer to the byte data, or %NULL.
 *
 * Since: 1.6.0
 **/
const guint8 *
fu_bytes_get_data_safe(GBytes *bytes, gsize *bufsz, GError **error)
{
	const guint8 *buf = g_bytes_get_data(bytes, bufsz);
	if (buf == NULL) {
		g_set_error(error, G_IO_ERROR, G_IO_ERROR_INVALID_DATA, "invalid data");
		return NULL;
	}
	return buf;
}