/*
 * Copyright (C) 2008-2014 Tobias Brunner
 * Copyright (C) 2008 Martin Willi
 * Hochschule fuer Technik Rapperswil
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

/**
 * @defgroup utils_i utils
 * @{ @ingroup utils
 */

#ifndef UTILS_H_
#define UTILS_H_

#include <sys/types.h>
#include <stdlib.h>
#include <stddef.h>
#include <sys/time.h>
#include <string.h>

#ifdef WIN32
# include "compat/windows.h"
#else
# define _GNU_SOURCE
# include <arpa/inet.h>
# include <sys/socket.h>
# include <netdb.h>
# include <netinet/in.h>
# include <sched.h>
# include <poll.h>
#endif

/**
 * strongSwan program return codes
 */
#define SS_RC_LIBSTRONGSWAN_INTEGRITY	64
#define SS_RC_DAEMON_INTEGRITY			65
#define SS_RC_INITIALIZATION_FAILED		66

#define SS_RC_FIRST	SS_RC_LIBSTRONGSWAN_INTEGRITY
#define SS_RC_LAST	SS_RC_INITIALIZATION_FAILED

/**
 * Number of bits in a byte
 */
#define BITS_PER_BYTE 8

/**
 * Default length for various auxiliary text buffers
 */
#define BUF_LEN 512

/**
 * Build assertion macro for integer expressions, evaluates to 0
 */
#define BUILD_ASSERT(x) (sizeof(char[(x) ? 0 : -1]))

/**
 * Build time check to assert a is an array, evaluates to 0
 *
 * The address of an array element has a pointer type, which is not compatible
 * to the array type.
 */
#define BUILD_ASSERT_ARRAY(a) \
		BUILD_ASSERT(!__builtin_types_compatible_p(typeof(a), typeof(&(a)[0])))

#include "utils/types.h"
#include "enum.h"
#include "utils/atomics.h"
#include "utils/byteorder.h"
#include "utils/string.h"
#include "utils/strerror.h"
#ifdef __APPLE__
# include "compat/apple.h"
#endif

/**
 * Directory separator character in paths on this platform
 */
#ifdef WIN32
# define DIRECTORY_SEPARATOR "\\"
#else
# define DIRECTORY_SEPARATOR "/"
#endif

/**
 * Initialize utility functions
 */
void utils_init();

/**
 * Deinitialize utility functions
 */
void utils_deinit();

/**
 * Helper function that compares two binary blobs for equality
 */
static inline bool memeq(const void *x, const void *y, size_t len)
{
	return memcmp(x, y, len) == 0;
}

/**
 * Same as memeq(), but with a constant runtime, safe for cryptographic use.
 */
bool memeq_const(const void *x, const void *y, size_t len);

/**
 * Calling memcpy() with NULL pointers, even with n == 0, results in undefined
 * behavior according to the C standard.  This version is guaranteed to not
 * access the pointers if n is 0.
 */
static inline void *memcpy_noop(void *dst, const void *src, size_t n)
{
	return n ? memcpy(dst, src, n) : dst;
}
#ifdef memcpy
# undef memcpy
#endif
#define memcpy(d,s,n) memcpy_noop(d,s,n)

/**
 * Calling memmove() with NULL pointers, even with n == 0, results in undefined
 * behavior according to the C standard.  This version is guaranteed to not
 * access the pointers if n is 0.
 */
static inline void *memmove_noop(void *dst, const void *src, size_t n)
{
	return n ? memmove(dst, src, n) : dst;
}
#ifdef memmove
# undef memmove
#endif
#define memmove(d,s,n) memmove_noop(d,s,n)

/**
 * Calling memset() with a NULL pointer, even with n == 0, results in undefined
 * behavior according to the C standard.  This version is guaranteed to not
 * access the pointer if n is 0.
 */
static inline void *memset_noop(void *s, int c, size_t n)
{
	return n ? memset(s, c, n) : s;
}
#ifdef memset
# undef memset
#endif
#define memset(s,c,n) memset_noop(s,c,n)

/**
 * Macro gives back larger of two values.
 */
#define max(x,y) ({ \
	typeof(x) _x = (x); \
	typeof(y) _y = (y); \
	_x > _y ? _x : _y; })

/**
 * Macro gives back smaller of two values.
 */
#define min(x,y) ({ \
	typeof(x) _x = (x); \
	typeof(y) _y = (y); \
	_x < _y ? _x : _y; })

/**
 * Call destructor of an object, if object != NULL
 */
#define DESTROY_IF(obj) if (obj) (obj)->destroy(obj)

/**
 * Call offset destructor of an object, if object != NULL
 */
#define DESTROY_OFFSET_IF(obj, offset) if (obj) obj->destroy_offset(obj, offset);

/**
 * Call function destructor of an object, if object != NULL
 */
#define DESTROY_FUNCTION_IF(obj, fn) if (obj) obj->destroy_function(obj, fn);

/**
 * Debug macro to follow control flow
 */
#define POS printf("%s, line %d\n", __FILE__, __LINE__)

/**
 * Object allocation/initialization macro, using designated initializer.
 */
#define INIT(this, ...) { (this) = malloc(sizeof(*(this))); \
						   *(this) = (typeof(*(this))){ __VA_ARGS__ }; }

/**
 * Aligning version of INIT().
 *
 * The returned pointer must be freed using free_align(), not free().
 *
 * @param this		object to allocate/initialize
 * @param align		alignment for allocation, in bytes
 * @param ...		initializer
 */
#define INIT_ALIGN(this, align, ...) { \
						(this) = malloc_align(sizeof(*(this)), align); \
						*(this) = (typeof(*(this))){ __VA_ARGS__ }; }

/**
 * Object allocation/initialization macro, with extra allocated bytes at tail.
 *
 * The extra space gets zero-initialized.
 *
 * @param this		pointer to object to allocate memory for
 * @param extra		number of bytes to allocate at end of this
 * @param ...		initializer
 */
#define INIT_EXTRA(this, extra, ...) { \
						typeof(extra) _extra = (extra); \
						(this) = malloc(sizeof(*(this)) + _extra); \
						*(this) = (typeof(*(this))){ __VA_ARGS__ }; \
						memset((this) + 1, 0, _extra); }

/**
 * Aligning version of INIT_EXTRA().
 *
 * The returned pointer must be freed using free_align(), not free().
 *
 * @param this		object to allocate/initialize
 * @param extra		number of bytes to allocate at end of this
 * @param align		alignment for allocation, in bytes
 * @param ...		initializer
 */
#define INIT_EXTRA_ALIGN(this, extra, align, ...) { \
						typeof(extra) _extra = (extra); \
						(this) = malloc_align(sizeof(*(this)) + _extra, align); \
						*(this) = (typeof(*(this))){ __VA_ARGS__ }; \
						memset((this) + 1, 0, _extra); }

/**
 * Method declaration/definition macro, providing private and public interface.
 *
 * Defines a method name with this as first parameter and a return value ret,
 * and an alias for this method with a _ prefix, having the this argument
 * safely casted to the public interface iface.
 * _name is provided a function pointer, but will get optimized out by GCC.
 */
#define METHOD(iface, name, ret, this, ...) \
	static ret name(union {iface *_public; this;} \
	__attribute__((transparent_union)), ##__VA_ARGS__); \
	static typeof(name) *_##name = (typeof(name)*)name; \
	static ret name(this, ##__VA_ARGS__)

/**
 * Same as METHOD(), but is defined for two public interfaces.
 */
#define METHOD2(iface1, iface2, name, ret, this, ...) \
	static ret name(union {iface1 *_public1; iface2 *_public2; this;} \
	__attribute__((transparent_union)), ##__VA_ARGS__); \
	static typeof(name) *_##name = (typeof(name)*)name; \
	static ret name(this, ##__VA_ARGS__)

/**
 * Callback declaration/definition macro, allowing casted first parameter.
 *
 * This is very similar to METHOD, but instead of casting the first parameter
 * to a public interface, it uses a void*. This allows type safe definition
 * of a callback function, while using the real type for the first parameter.
 */
#define CALLBACK(name, ret, param1, ...) \
	static ret _cb_##name(union {void *_generic; param1;} \
	__attribute__((transparent_union)), ##__VA_ARGS__); \
	static typeof(_cb_##name) *name = (typeof(_cb_##name)*)_cb_##name; \
	static ret _cb_##name(param1, ##__VA_ARGS__)

/**
 * This macro allows counting the number of arguments passed to a macro.
 * Combined with the VA_ARGS_DISPATCH() macro this can be used to implement
 * macro overloading based on the number of arguments.
 * 0 to 10 arguments are currently supported.
 */
#define VA_ARGS_NUM(...) _VA_ARGS_NUM(0,##__VA_ARGS__,10,9,8,7,6,5,4,3,2,1,0)
#define _VA_ARGS_NUM(_0,_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,NUM,...) NUM

/**
 * This macro can be used to dispatch a macro call based on the number of given
 * arguments, for instance:
 *
 * @code
 * #define MY_MACRO(...) VA_ARGS_DISPATCH(MY_MACRO, __VA_ARGS__)(__VA_ARGS__)
 * #define MY_MACRO1(arg) one_arg(arg)
 * #define MY_MACRO2(arg1,arg2) two_args(arg1,arg2)
 * @endcode
 *
 * MY_MACRO() can now be called with either one or two arguments, which will
 * resolve to one_arg(arg) or two_args(arg1,arg2), respectively.
 */
#define VA_ARGS_DISPATCH(func, ...) _VA_ARGS_DISPATCH(func, VA_ARGS_NUM(__VA_ARGS__))
#define _VA_ARGS_DISPATCH(func, num) __VA_ARGS_DISPATCH(func, num)
#define __VA_ARGS_DISPATCH(func, num) func ## num

/**
 * Macro to allocate a sized type.
 */
#define malloc_thing(thing) ((thing*)malloc(sizeof(thing)))

/**
 * Get the number of elements in an array
 */
#define countof(array) (sizeof(array)/sizeof((array)[0]) \
						+ BUILD_ASSERT_ARRAY(array))

/**
 * Ignore result of functions tagged with warn_unused_result attributes
 */
#define ignore_result(call) { if(call){}; }

/**
 * Assign a function as a class method
 */
#define ASSIGN(method, function) (method = (typeof(method))function)

/**
 * time_t not defined
 */
#define UNDEFINED_TIME 0

/**
 * Maximum time since epoch causing wrap-around on Jan 19 03:14:07 UTC 2038
 */
#define TIME_32_BIT_SIGNED_MAX	0x7fffffff

typedef enum status_t status_t;

/**
 * Return values of function calls.
 */
enum status_t {
	/**
	 * Call succeeded.
	 */
	SUCCESS,

	/**
	 * Call failed.
	 */
	FAILED,

	/**
	 * Out of resources.
	 */
	OUT_OF_RES,

	/**
	 * The suggested operation is already done
	 */
	ALREADY_DONE,

	/**
	 * Not supported.
	 */
	NOT_SUPPORTED,

	/**
	 * One of the arguments is invalid.
	 */
	INVALID_ARG,

	/**
	 * Something could not be found.
	 */
	NOT_FOUND,

	/**
	 * Error while parsing.
	 */
	PARSE_ERROR,

	/**
	 * Error while verifying.
	 */
	VERIFY_ERROR,

	/**
	 * Object in invalid state.
	 */
	INVALID_STATE,

	/**
	 * Destroy object which called method belongs to.
	 */
	DESTROY_ME,

	/**
	 * Another call to the method is required.
	 */
	NEED_MORE,
};

/**
 * enum_names for type status_t.
 */
extern enum_name_t *status_names;

typedef enum tty_escape_t tty_escape_t;

/**
 * Excape codes for tty colors
 */
enum tty_escape_t {
	/** text properties */
	TTY_RESET,
	TTY_BOLD,
	TTY_UNDERLINE,
	TTY_BLINKING,

	/** foreground colors */
	TTY_FG_BLACK,
	TTY_FG_RED,
	TTY_FG_GREEN,
	TTY_FG_YELLOW,
	TTY_FG_BLUE,
	TTY_FG_MAGENTA,
	TTY_FG_CYAN,
	TTY_FG_WHITE,
	TTY_FG_DEF,

	/** background colors */
	TTY_BG_BLACK,
	TTY_BG_RED,
	TTY_BG_GREEN,
	TTY_BG_YELLOW,
	TTY_BG_BLUE,
	TTY_BG_MAGENTA,
	TTY_BG_CYAN,
	TTY_BG_WHITE,
	TTY_BG_DEF,
};

/**
 * Get the escape string for a given TTY color, empty string on non-tty fd
 */
char* tty_escape_get(int fd, tty_escape_t escape);

/**
 * Handle struct timeval like an own type.
 */
typedef struct timeval timeval_t;

/**
 * Handle struct timespec like an own type.
 */
typedef struct timespec timespec_t;

/**
 * malloc(), but returns aligned memory.
 *
 * The returned pointer must be freed using free_align(), not free().
 *
 * @param size			size of allocated data
 * @param align			alignment, up to 255 bytes, usually a power of 2
 * @return				allocated hunk, aligned to align bytes
 */
void* malloc_align(size_t size, u_int8_t align);

/**
 * Free a hunk allocated by malloc_align().
 *
 * @param ptr			hunk to free
 */
void free_align(void *ptr);

/**
 * Same as memcpy, but XORs src into dst instead of copy
 */
void memxor(u_int8_t dest[], u_int8_t src[], size_t n);

/**
 * Safely overwrite n bytes of memory at ptr with zero, non-inlining variant.
 */
void memwipe_noinline(void *ptr, size_t n);

/**
 * Safely overwrite n bytes of memory at ptr with zero, inlining variant.
 */
static inline void memwipe_inline(void *ptr, size_t n)
{
	volatile char *c = (volatile char*)ptr;
	size_t m, i;

	/* byte wise until long aligned */
	for (i = 0; (uintptr_t)&c[i] % sizeof(long) && i < n; i++)
	{
		c[i] = 0;
	}
	/* word wise */
	if (n >= sizeof(long))
	{
		for (m = n - sizeof(long); i <= m; i += sizeof(long))
		{
			*(volatile long*)&c[i] = 0;
		}
	}
	/* byte wise of the rest */
	for (; i < n; i++)
	{
		c[i] = 0;
	}
}

/**
 * Safely overwrite n bytes of memory at ptr with zero, auto-inlining variant.
 */
static inline void memwipe(void *ptr, size_t n)
{
	if (!ptr)
	{
		return;
	}
	if (__builtin_constant_p(n))
	{
		memwipe_inline(ptr, n);
	}
	else
	{
		memwipe_noinline(ptr, n);
	}
}

/**
 * A variant of strstr with the characteristics of memchr, where haystack is not
 * a null-terminated string but simply a memory area of length n.
 */
void *memstr(const void *haystack, const char *needle, size_t n);

/**
 * Replacement for memrchr(3) if it is not provided by the C library.
 *
 * @param s		start of the memory area to search
 * @param c		character to search
 * @param n		length of memory area to search
 * @return		pointer to the found character or NULL
 */
void *utils_memrchr(const void *s, int c, size_t n);

#ifndef HAVE_MEMRCHR
#define memrchr(s,c,n) utils_memrchr(s,c,n)
#endif

/**
 * Portable function to wait for SIGINT/SIGTERM (or equivalent).
 */
void wait_sigint();

/**
 * Like dirname(3) returns the directory part of the given null-terminated
 * pathname, up to but not including the final '/' (or '.' if no '/' is found).
 * Trailing '/' are not counted as part of the pathname.
 *
 * The difference is that it does this in a thread-safe manner (i.e. it does not
 * use static buffers) and does not modify the original path.
 *
 * @param path		original pathname
 * @return			allocated directory component
 */
char *path_dirname(const char *path);

/**
 * Like basename(3) returns the filename part of the given null-terminated path,
 * i.e. the part following the final '/' (or '.' if path is empty or NULL).
 * Trailing '/' are not counted as part of the pathname.
 *
 * The difference is that it does this in a thread-safe manner (i.e. it does not
 * use static buffers) and does not modify the original path.
 *
 * @param path		original pathname
 * @return			allocated filename component
 */
char *path_basename(const char *path);

/**
 * Check if a given path is absolute.
 *
 * @param path		path to check
 * @return			TRUE if absolute, FALSE if relative
 */
bool path_absolute(const char *path);

/**
 * Creates a directory and all required parent directories.
 *
 * @param path		path to the new directory
 * @param mode		permissions of the new directory/directories
 * @return			TRUE on success
 */
bool mkdir_p(const char *path, mode_t mode);

#ifndef HAVE_CLOSEFROM
/**
 * Close open file descriptors greater than or equal to lowfd.
 *
 * @param lowfd		start closing file descriptors from here
 */
void closefrom(int lowfd);
#endif

/**
 * Get a timestamp from a monotonic time source.
 *
 * While the time()/gettimeofday() functions are affected by leap seconds
 * and system time changes, this function returns ever increasing monotonic
 * time stamps.
 *
 * @param tv		timeval struct receiving monotonic timestamps, or NULL
 * @return			monotonic timestamp in seconds
 */
time_t time_monotonic(timeval_t *tv);

/**
 * Add the given number of milliseconds to the given timeval struct
 *
 * @param tv		timeval struct to modify
 * @param ms		number of milliseconds
 */
static inline void timeval_add_ms(timeval_t *tv, u_int ms)
{
	tv->tv_usec += ms * 1000;
	while (tv->tv_usec >= 1000000 /* 1s */)
	{
		tv->tv_usec -= 1000000;
		tv->tv_sec++;
	}
}

/**
 * returns null
 */
void *return_null();

/**
 * No-Operation function
 */
void nop();

/**
 * returns TRUE
 */
bool return_true();

/**
 * returns FALSE
 */
bool return_false();

/**
 * returns FAILED
 */
status_t return_failed();

/**
 * returns SUCCESS
 */
status_t return_success();

/**
 * Get the padding required to make size a multiple of alignment
 */
static inline size_t pad_len(size_t size, size_t alignment)
{
	size_t remainder;

	remainder = size % alignment;
	return remainder ? alignment - remainder : 0;
}

/**
 * Round up size to be multiple of alignment
 */
static inline size_t round_up(size_t size, size_t alignment)
{
	return size + pad_len(size, alignment);
}

/**
 * Round down size to be a multiple of alignment
 */
static inline size_t round_down(size_t size, size_t alignment)
{
	return size - (size % alignment);
}

#ifndef HAVE_FMEMOPEN
# ifdef HAVE_FUNOPEN
#  define HAVE_FMEMOPEN
#  define HAVE_FMEMOPEN_FALLBACK
#  include <stdio.h>
/**
 * fmemopen(3) fallback using BSD funopen.
 *
 * We could also provide one using fopencookie(), but should we have it we
 * most likely have fmemopen().
 *
 * fseek() is currently not supported.
 */
FILE *fmemopen(void *buf, size_t size, const char *mode);
# endif /* FUNOPEN */
#endif /* FMEMOPEN */

/**
 * printf hook for time_t.
 *
 * Arguments are:
 *	time_t* time, bool utc
 */
int time_printf_hook(printf_hook_data_t *data, printf_hook_spec_t *spec,
					 const void *const *args);

/**
 * printf hook for time_t deltas.
 *
 * Arguments are:
 *	time_t* begin, time_t* end
 */
int time_delta_printf_hook(printf_hook_data_t *data, printf_hook_spec_t *spec,
						   const void *const *args);

/**
 * printf hook for memory areas.
 *
 * Arguments are:
 *	u_char *ptr, u_int len
 */
int mem_printf_hook(printf_hook_data_t *data, printf_hook_spec_t *spec,
					const void *const *args);

#endif /** UTILS_H_ @}*/