/**
 * @file   internal.h
 * @brief  Declarations of internal data structures and functions
 *
 * @cond internal
 */

/*-
 * Copyright (c) 2016-2017 Stanley Uche Godfrey
 * Copyright (c) 2016-2018 Jonathan Anderson
 * All rights reserved.
 *
 * This software was developed at Memorial University under the
 * NSERC Discovery program (RGPIN-2015-06048).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef LIBPO_INTERNAL_H
#define LIBPO_INTERNAL_H

#ifdef __wasilibc_unmodified_upstream
#include <sys/cdefs.h>
#endif

#ifdef __wasilibc_unmodified_upstream
#ifdef WITH_CAPSICUM
#include <sys/capsicum.h>
#endif
#else
// We do Capsicum-style rights-checking, though we use the WASI API directly
// rather than the Capsicum API.
#define WITH_CAPSICUM
#endif

#include <assert.h>
#include <stdbool.h>

#include "libpreopen.h"

/**
 * An entry in a po_map.
 *
 * @internal
 */
struct po_map_entry {
	/**
	 * The name this file or directory is mapped to.
	 *
	 * This name should look like a path, but it does not necessarily need
	 * match to match the path it was originally obtained from.
	 */
	const char *name;

	/** File descriptor (which may be a directory) */
	int fd;

#ifdef WITH_CAPSICUM
	/** Capability rights associated with the file descriptor */
#ifdef __wasilibc_unmodified_upstream
	cap_rights_t rights;
#else
	__wasi_rights_t rights_base;
	__wasi_rights_t rights_inheriting;
#endif
#endif
};

// Documented in external header file
struct po_map {
	//! @internal
	int refcount;
	struct po_map_entry *entries;
	size_t capacity;
	size_t length;
};


/**
 * Is a directory a prefix of a given path?
 *
 * @param   dir     a directory path, e.g., `/foo/bar`
 * @param   dirlen  the length of @b dir
 * @param   path    a path that may have @b dir as a prefix,
 *                  e.g., `/foo/bar/baz`
 *
 * @internal
 */
#ifdef __wasilibc_unmodified_upstream
#else
static
#endif
bool	po_isprefix(const char *dir, size_t dirlen, const char *path);


/**
 * Check that a @ref po_map is valid (assert out if it's not).
 *
 * @internal
 */
#ifdef NDEBUG
#define po_map_assertvalid(...)
#else
#ifdef __wasilibc_unmodified_upstream
#else
static
#endif
void	po_map_assertvalid(const struct po_map *);
#endif

/**
 * Enlarge a @ref po_map's capacity.
 *
 * This results in new memory being allocated and existing entries being copied.
 * If the allocation fails, the function will return NULL but the original
 * map will remain valid.
 *
 * @internal
 */
#ifdef __wasilibc_unmodified_upstream
#else
static
#endif
struct po_map* po_map_enlarge(struct po_map *map);

#ifdef __wasilibc_unmodified_upstream
/**
 * Store an error message in the global "last error message" buffer.
 *
 * @internal
 */
void po_errormessage(const char *msg);
#endif

/**
 * Set the default map used by the libpreopen libc wrappers.
 *
 * If there is an existing default map, it will be freed before it is replaced.
 * Passing NULL to this function will thus clear the default map.
 */
#ifdef __wasilibc_unmodified_upstream
void po_set_libc_map(struct po_map *);
#endif

#endif /* LIBPO_INTERNAL_H */

/** @endcond */