printf-hook-builtin: Add a new "builtin" backend using its own printf() routines

Overloads printf C library functions by a self-contained implementation,
based on klibc. Does not yet feature all the required default formatters,
including those for floating point values.

5 files changed, 1032 insertions, 2 deletions

diff --git a/configure.ac b/configure.ac
index 472c539e3..0f558161e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -624,7 +624,7 @@ AC_CHECK_FUNC(
 		[AC_DEFINE([HAVE_PRINTF_FUNCTION], [], [have register_printf_function()])],
 		[
 			AC_MSG_NOTICE([printf does not support custom format specifiers!])
-			vstr=true
+			builtin_printf=true
 		]
 	)]
 )
@@ -632,6 +632,11 @@ AC_CHECK_FUNC(
 if test x$vstr = xtrue; then
 	AC_CHECK_LIB([vstr],[main],[LIBS="$LIBS"],[AC_MSG_ERROR([Vstr string library not found])],[])
 	AC_DEFINE([USE_VSTR], [], [use vstring library for printf hooks])
+	builtin_printf=false
+fi
+
+if test x$builtin_printf = xtrue; then
+	AC_DEFINE([USE_BUILTIN_PRINTF], [], [using builtin printf for printf hooks])
 fi
 
 if test x$gmp = xtrue; then
@@ -1278,6 +1283,7 @@ AM_CONDITIONAL(USE_FILE_CONFIG, test x$stroke = xtrue)
 AM_CONDITIONAL(USE_IPSEC_SCRIPT, test x$stroke = xtrue -o x$tools = xtrue -o x$conftest = xtrue)
 AM_CONDITIONAL(USE_LIBCAP, test x$capabilities = xlibcap)
 AM_CONDITIONAL(USE_VSTR, test x$vstr = xtrue)
+AM_CONDITIONAL(USE_BUILTIN_PRINTF, test x$builtin_printf = xtrue)
 AM_CONDITIONAL(USE_SIMAKA, test x$simaka = xtrue)
 AM_CONDITIONAL(USE_TLS, test x$tls = xtrue)
 AM_CONDITIONAL(USE_RADIUS, test x$radius = xtrue)
diff --git a/src/libstrongswan/Makefile.am b/src/libstrongswan/Makefile.am
index c0f8c39dc..54b19e139 100644
--- a/src/libstrongswan/Makefile.am
+++ b/src/libstrongswan/Makefile.am
@@ -79,7 +79,7 @@ threading/rwlock.h threading/rwlock_condvar.h threading/lock_profiler.h \
 utils/utils.h utils/chunk.h utils/debug.h utils/enum.h utils/identification.h \
 utils/lexparser.h utils/optionsfrom.h utils/capabilities.h utils/backtrace.h \
 utils/leak_detective.h utils/printf_hook/printf_hook.h \
-utils/printf_hook/printf_hook_vstr.h \
+utils/printf_hook/printf_hook_vstr.h utils/printf_hook/printf_hook_builtin.h \
 utils/settings.h utils/integrity_checker.h
 endif
 
@@ -119,9 +119,16 @@ if USE_VSTR
   libstrongswan_la_LIBADD += -lvstr
 endif
 
+if USE_BUILTIN_PRINTF
+  libstrongswan_la_SOURCES += utils/printf_hook/printf_hook_builtin.c
+  libstrongswan_la_LIBADD += -lm
+endif
+
+if !USE_BUILTIN_PRINTF
 if !USE_VSTR
   libstrongswan_la_SOURCES += utils/printf_hook/printf_hook_glibc.c
 endif
+endif
 
 if USE_LIBCAP
   libstrongswan_la_LIBADD += -lcap
diff --git a/src/libstrongswan/utils/printf_hook/printf_hook.h b/src/libstrongswan/utils/printf_hook/printf_hook.h
index 5520de154..c1d6fa90d 100644
--- a/src/libstrongswan/utils/printf_hook/printf_hook.h
+++ b/src/libstrongswan/utils/printf_hook/printf_hook.h
@@ -31,6 +31,8 @@ typedef enum printf_hook_argtype_t printf_hook_argtype_t;
 
 #if defined(USE_VSTR)
 # include "printf_hook_vstr.h"
+#elif defined(USE_BUILTIN_PRINTF)
+# include "printf_hook_builtin.h"
 #endif
 
 /**
diff --git a/src/libstrongswan/utils/printf_hook/printf_hook_builtin.c b/src/libstrongswan/utils/printf_hook/printf_hook_builtin.c
new file mode 100644
index 000000000..5f4907979
--- /dev/null
+++ b/src/libstrongswan/utils/printf_hook/printf_hook_builtin.c
@@ -0,0 +1,933 @@
+/*
+ * Copyright (C) 2013 Martin Willi
+ * Copyright (C) 2013 revosec AG
+ *
+ * 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.
+ */
+
+/**
+ * Copyright (C) 2002-2006 H. Peter Anvin
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "printf_hook.h"
+
+#include <utils/utils.h>
+#include <utils/debug.h>
+#include <collections/hashtable.h>
+
+#include <inttypes.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+
+#define PRINTF_BUF_LEN 8192
+#define ARGS_MAX 3
+
+typedef struct private_printf_hook_t private_printf_hook_t;
+typedef struct printf_hook_handler_t printf_hook_handler_t;
+
+/**
+ * private data of printf_hook
+ */
+struct private_printf_hook_t {
+
+	/**
+	 * public functions
+	 */
+	printf_hook_t public;
+};
+
+/**
+ * struct with information about a registered handler
+ */
+struct printf_hook_handler_t {
+
+	/**
+	 * callback function
+	 */
+	printf_hook_function_t hook;
+
+	/**
+	 * number of arguments
+	 */
+	int numargs;
+
+	/**
+	 * types of the arguments
+	 */
+	int argtypes[ARGS_MAX];
+};
+
+/**
+ * Data to pass to a printf hook.
+ */
+struct printf_hook_data_t {
+
+	/**
+	 * Output buffer
+	 */
+	char *q;
+
+	/**
+	 * Remaining bytes in q
+	 */
+	size_t n;
+};
+
+/**
+ * Registered hooks (char => printf_hook_handler_t)
+ */
+static hashtable_t *hooks;
+
+/**
+ * builtin-printf variant of print_in_hook()
+ */
+size_t print_in_hook(printf_hook_data_t *data, char *fmt, ...)
+{
+	int written;
+	va_list args;
+
+	va_start(args, fmt);
+	written = builtin_vsnprintf(data->q, data->n, fmt, args);
+	va_end(args);
+
+	if (written > data->n)
+	{
+		written = data->n;
+	}
+	data->q += written;
+	data->n += written;
+	return written;
+}
+
+METHOD(printf_hook_t, add_handler, void,
+	private_printf_hook_t *this, char spec, printf_hook_function_t hook, ...)
+{
+	int i = -1;
+	bool failed = FALSE;
+	printf_hook_handler_t *handler;
+	printf_hook_argtype_t argtype;
+	va_list args;
+
+	INIT(handler,
+		.hook = hook,
+	);
+
+	va_start(args, hook);
+	while (!failed)
+	{
+		argtype = va_arg(args, printf_hook_argtype_t);
+
+		if (argtype == PRINTF_HOOK_ARGTYPE_END)
+		{
+			break;
+		}
+		if (++i >= countof(handler->argtypes))
+		{
+			DBG1(DBG_LIB, "Too many arguments for printf hook with "
+				 "specifier '%c', not registered!", spec);
+			failed = TRUE;
+			break;
+		}
+		handler->argtypes[i] = argtype;
+	}
+	va_end(args);
+
+	handler->numargs = i + 1;
+	if (!failed && handler->numargs > 0)
+	{
+		free(hooks->put(hooks, (void*)(uintptr_t)spec, handler));
+	}
+	else
+	{
+		free(handler);
+	}
+}
+
+/**
+ * Printf format modifier flags
+ */
+typedef enum {
+	FL_ZERO		= 0x01,
+	FL_MINUS	= 0x02,
+	FL_PLUS		= 0x04,
+	FL_TICK		= 0x08,
+	FL_SPACE	= 0x10,
+	FL_HASH		= 0x20,
+	FL_SIGNED	= 0x40,
+	FL_UPPER	= 0x80,
+} bpf_flag_t;
+
+/**
+ * Size of format string arguments
+ */
+typedef enum {
+	RNK_CHAR		= -2,
+	RNK_SHORT		= -1,
+	RNK_INT			=  0,
+	RNK_LONG		=  1,
+	RNK_LONGLONG	=  2,
+
+	RNK_INTMAX		= RNK_LONGLONG,
+	RNK_SIZE_T		= RNK_LONG,
+	RNK_PTRDIFF_T	= RNK_LONG,
+
+	RNK_MIN			= RNK_CHAR,
+	RNK_MAX			= RNK_LONGLONG,
+} bpf_rank_t;
+
+/**
+ * Printf specifier Parser state
+ */
+typedef enum {
+	/* Ground state */
+	ST_NORMAL,
+	/* Special flags */
+	ST_FLAGS,
+	/* Field width */
+	ST_WIDTH,
+	/* Field precision */
+	ST_PREC,
+	/* Length or conversion modifiers */
+	ST_MODIFIERS,
+} bpf_state_t;
+
+#define EMIT(x) ({ if (o<n){*q++ = (x);} o++; })
+
+/**
+ * Write an integer argument to q, using flags, base, width and precision
+ */
+static size_t format_int(char *q, size_t n, uintmax_t val, bpf_flag_t flags,
+						 int base, int width, int prec)
+{
+	static const char lcdigits[] = "0123456789abcdef";
+	static const char ucdigits[] = "0123456789ABCDEF";
+	char *qq;
+	size_t o = 0, oo;
+	const char *digits;
+	uintmax_t tmpval;
+	int minus = 0;
+	int ndigits = 0, nchars;
+	int tickskip, b4tick;
+
+	/* Select type of digits */
+	digits = (flags & FL_UPPER) ? ucdigits : lcdigits;
+
+	/* If signed, separate out the minus */
+	if (flags & FL_SIGNED && (intmax_t) val < 0)
+	{
+		minus = 1;
+		val = (uintmax_t) (-(intmax_t) val);
+	}
+
+	/* Count the number of digits needed.  This returns zero for 0. */
+	tmpval = val;
+	while (tmpval)
+	{
+		tmpval /= base;
+		ndigits++;
+	}
+
+	/* Adjust ndigits for size of output */
+	if (flags & FL_HASH && base == 8)
+	{
+		if (prec < ndigits + 1)
+		{
+			prec = ndigits + 1;
+		}
+	}
+
+	if (ndigits < prec)
+	{
+		/* Mandatory number padding */
+		ndigits = prec;
+	}
+	else if (val == 0)
+	{
+		/* Zero still requires space */
+		ndigits = 1;
+	}
+
+	/* For ', figure out what the skip should be */
+	if (flags & FL_TICK)
+	{
+		if (base == 16)
+		{
+			tickskip = 4;
+		}
+		else
+		{
+			tickskip = 3;
+		}
+	}
+	else
+	{
+		/* No tick marks */
+		tickskip = ndigits;
+	}
+
+	/* Tick marks aren't digits, but generated by the number converter */
+	ndigits += (ndigits - 1) / tickskip;
+
+	/* Now compute the number of nondigits */
+	nchars = ndigits;
+
+	if (minus || (flags & (FL_PLUS | FL_SPACE)))
+	{
+		/* Need space for sign */
+		nchars++;
+	}
+	if ((flags & FL_HASH) && base == 16)
+	{
+		/* Add 0x for hex */
+		nchars += 2;
+	}
+
+	/* Emit early space padding */
+	if (!(flags & (FL_MINUS | FL_ZERO)) && width > nchars)
+	{
+		while (width > nchars)
+		{
+			EMIT(' ');
+			width--;
+		}
+	}
+
+	/* Emit nondigits */
+	if (minus)
+	{
+		EMIT('-');
+	}
+	else if (flags & FL_PLUS)
+	{
+		EMIT('+');
+	}
+	else if (flags & FL_SPACE)
+	{
+		EMIT(' ');
+	}
+
+	if ((flags & FL_HASH) && base == 16)
+	{
+		EMIT('0');
+		EMIT((flags & FL_UPPER) ? 'X' : 'x');
+	}
+
+	/* Emit zero padding */
+	if ((flags & (FL_MINUS | FL_ZERO)) == FL_ZERO && width > ndigits)
+	{
+		while (width > nchars)
+		{
+			EMIT('0');
+			width--;
+		}
+	}
+
+	/* Generate the number.  This is done from right to left. */
+	/* Advance the pointer to end of number */
+	q += ndigits;
+	o += ndigits;
+	/* Temporary values */
+	qq = q;
+	oo = o;
+
+	b4tick = tickskip;
+	while (ndigits > 0)
+	{
+		if (!b4tick--)
+		{
+			qq--;
+			oo--;
+			ndigits--;
+			if (oo < n)
+			{
+				*qq = '_';
+			}
+			b4tick = tickskip - 1;
+		}
+		qq--;
+		oo--;
+		ndigits--;
+		if (oo < n)
+		{
+			*qq = digits[val % base];
+		}
+		val /= base;
+	}
+
+	/* Emit late space padding */
+	while ((flags & FL_MINUS) && width > nchars)
+	{
+		EMIT(' ');
+		width--;
+	}
+
+	return o;
+}
+
+int builtin_vsnprintf(char *buffer, size_t n, const char *format, va_list ap)
+{
+	const char *p = format;
+	char ch;
+	char *q = buffer;
+	/* Number of characters output */
+	size_t o = 0;
+	uintmax_t val = 0;
+	/* Default rank */
+	int rank = RNK_INT;
+	int width = 0;
+	int prec = -1;
+	int base;
+	size_t sz;
+	bpf_flag_t flags = 0;
+	bpf_state_t state = ST_NORMAL;
+	/* %s string argument */
+	const char *sarg;
+	/* %c char argument */
+	char carg;
+	/* String length */
+	int slen;
+
+	while ((ch = *p++))
+	{
+		switch (state)
+		{
+			case ST_NORMAL:
+			{
+				if (ch == '%')
+				{
+					state = ST_FLAGS;
+					flags = 0;
+					rank = RNK_INT;
+					width = 0;
+					prec = -1;
+				}
+				else
+				{
+					EMIT(ch);
+				}
+				break;
+			}
+			case ST_FLAGS:
+			{
+				switch (ch)
+				{
+					case '-':
+						flags |= FL_MINUS;
+						break;
+					case '+':
+						flags |= FL_PLUS;
+						break;
+					case '\'':
+						flags |= FL_TICK;
+						break;
+					case ' ':
+						flags |= FL_SPACE;
+						break;
+					case '#':
+						flags |= FL_HASH;
+						break;
+					case '0':
+						flags |= FL_ZERO;
+						break;
+					default:
+						state = ST_WIDTH;
+						/* Process this character again */
+						p--;
+						break;
+				}
+				break;
+			}
+			case ST_WIDTH:
+			{
+				if (ch >= '0' && ch <= '9')
+				{
+					width = width * 10 + (ch - '0');
+				}
+				else if (ch == '*')
+				{
+					width = va_arg(ap, int);
+					if (width < 0)
+					{
+						width = -width;
+						flags |= FL_MINUS;
+					}
+				}
+				else if (ch == '.')
+				{
+					/* Precision given */
+					prec = 0;
+					state = ST_PREC;
+				}
+				else
+				{
+					state = ST_MODIFIERS;
+					/* Process this character again */
+					p--;
+				}
+				break;
+			}
+			case ST_PREC:
+			{
+				if (ch >= '0' && ch <= '9')
+				{
+					prec = prec * 10 + (ch - '0');
+				}
+				else if (ch == '*')
+				{
+					prec = va_arg(ap, int);
+					if (prec < 0)
+					{
+						prec = -1;
+					}
+				}
+				else
+				{
+					state = ST_MODIFIERS;
+					/* Process this character again */
+					p--;
+				}
+				break;
+			}
+			case ST_MODIFIERS:
+			{
+				switch (ch)
+				{
+					/* Length modifiers - nonterminal sequences */
+					case 'h':
+						rank--;
+						break;
+					case 'l':
+						rank++;
+						break;
+					case 'j':
+						rank = RNK_INTMAX;
+						break;
+					case 'z':
+						rank = RNK_SIZE_T;
+						break;
+					case 't':
+						rank = RNK_PTRDIFF_T;
+						break;
+					case 'L':
+					case 'q':
+						rank += 2;
+						break;
+					default:
+					{
+						/* Output modifiers - terminal sequences */
+
+						/* Next state will be normal */
+						state = ST_NORMAL;
+
+						/* Canonicalize rank */
+						if (rank < RNK_MIN)
+						{
+							rank = RNK_MIN;
+						}
+						else if (rank > RNK_MAX)
+						{
+							rank = RNK_MAX;
+						}
+
+						switch (ch)
+						{
+							case 'P':
+							{
+								/* Upper case pointer */
+								flags |= FL_UPPER;
+								/* fall through */
+							}
+							case 'p':
+							{
+								/* Pointer */
+								base = 16;
+								prec = (CHAR_BIT*sizeof(void *)+3)/4;
+								flags |= FL_HASH;
+								val = (uintmax_t)(uintptr_t)
+									va_arg(ap, void *);
+								goto is_integer;
+							}
+							case 'd':
+							case 'i':
+							{
+								/* Signed decimal output */
+								base = 10;
+								flags |= FL_SIGNED;
+								switch (rank)
+								{
+									case RNK_CHAR:
+										/* Yes, all these casts are
+										   needed... */
+										val = (uintmax_t)(intmax_t)(signed char)
+												va_arg(ap, signed int);
+										break;
+									case RNK_SHORT:
+										val = (uintmax_t)(intmax_t)(signed short)
+												va_arg(ap, signed int);
+										break;
+									case RNK_INT:
+										val = (uintmax_t)(intmax_t)
+												va_arg(ap, signed int);
+										break;
+									case RNK_LONG:
+										val = (uintmax_t)(intmax_t)
+												va_arg(ap, signed long);
+										break;
+									case RNK_LONGLONG:
+										val = (uintmax_t)(intmax_t)
+												va_arg(ap, signed long long);
+										break;
+								}
+								goto is_integer;
+							}
+							case 'o':
+							{
+								/* Octal */
+								base = 8;
+								goto is_unsigned;
+							}
+							case 'u':
+							{
+								/* Unsigned decimal */
+								base = 10;
+								goto is_unsigned;
+							}
+							case 'X':
+							{
+								/* Upper case hexadecimal */
+								flags |= FL_UPPER;
+								/* fall through */
+							}
+							case 'x':
+							{
+								/* Hexadecimal */
+								base = 16;
+								goto is_unsigned;
+							}
+							is_unsigned:
+							{
+								switch (rank) {
+									case RNK_CHAR:
+										val = (uintmax_t)(unsigned char)
+												va_arg(ap, unsigned int);
+										break;
+									case RNK_SHORT:
+										val = (uintmax_t)(unsigned short)
+												va_arg(ap, unsigned int);
+										break;
+									case RNK_INT:
+										val = (uintmax_t)
+												va_arg(ap, unsigned int);
+										break;
+									case RNK_LONG:
+										val = (uintmax_t)
+												va_arg(ap, unsigned long);
+										break;
+									case RNK_LONGLONG:
+										val = (uintmax_t)
+												va_arg(ap, unsigned long long);
+										break;
+								}
+								goto is_integer;
+							}
+							is_integer:
+							{
+								sz = format_int(q, (o < n) ? n - o : 0,
+												val, flags, base, width, prec);
+								q += sz;
+								o += sz;
+								break;
+							}
+							case 'c':
+							{
+								/* Character */
+								carg = (char)va_arg(ap, int);
+								sarg = &carg;
+								slen = 1;
+								goto is_string;
+							}
+							case 's':
+							{
+								/* String */
+								sarg = va_arg(ap, const char *);
+								sarg = sarg ? sarg : "(null)";
+								slen = strlen(sarg);
+								goto is_string;
+							}
+							is_string:
+							{
+								char sch;
+								int i;
+
+								if (prec != -1 && slen > prec)
+								{
+									slen = prec;
+								}
+
+								if (width > slen && !(flags & FL_MINUS))
+								{
+									char pad = (flags & FL_ZERO) ? '0' : ' ';
+									while (width > slen)
+									{
+										EMIT(pad);
+										width--;
+									}
+								}
+								for (i = slen; i; i--)
+								{
+									sch = *sarg++;
+									EMIT(sch);
+								}
+								if (width > slen && (flags & FL_MINUS))
+								{
+									while (width > slen)
+									{
+										EMIT(' ');
+										width--;
+									}
+								}
+								break;
+							}
+							case 'n':
+							{
+								/* Output the number of characters written */
+								switch (rank)
+								{
+									case RNK_CHAR:
+										*va_arg(ap, signed char *) = o;
+										break;
+									case RNK_SHORT:
+										*va_arg(ap, signed short *) = o;
+										break;
+									case RNK_INT:
+										*va_arg(ap, signed int *) = o;
+										break;
+									case RNK_LONG:
+										*va_arg(ap, signed long *) = o;
+										break;
+									case RNK_LONGLONG:
+										*va_arg(ap, signed long long *) = o;
+										break;
+								}
+								break;
+							}
+							default:
+							{
+								printf_hook_handler_t *handler;
+
+								handler = hooks->get(hooks, (void*)(uintptr_t)ch);
+								if (handler)
+								{
+									const void *args[ARGS_MAX];
+									int i, iargs[ARGS_MAX];
+									void *pargs[ARGS_MAX];
+									printf_hook_spec_t spec =  {
+										.hash = flags & FL_HASH,
+										.plus = flags & FL_PLUS,
+										.minus = flags & FL_MINUS,
+										.width = width,
+									};
+									printf_hook_data_t data = {
+										.q = q,
+										.n = (o < n) ? n - o : 0,
+									};
+
+									for (i = 0; i < handler->numargs; i++)
+									{
+										switch (handler->argtypes[i])
+										{
+											case PRINTF_HOOK_ARGTYPE_INT:
+												iargs[i] = va_arg(ap, int);
+												args[i] = &iargs[i];
+												break;
+											case PRINTF_HOOK_ARGTYPE_POINTER:
+												pargs[i] = va_arg(ap, void*);
+												args[i] = &pargs[i];
+												break;
+										}
+									}
+									sz = handler->hook(&data, &spec, args);
+									q += sz;
+									o += sz;
+								}
+								else
+								{
+									/* Anything else, including % */
+									EMIT(ch);
+								}
+								break;
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+
+	/* Null-terminate the string */
+	if (o < n)
+	{
+		/* No overflow */
+		*q = '\0';
+	}
+	else if (n > 0)
+	{
+		/* Overflow - terminate at end of buffer */
+		buffer[n - 1] = '\0';
+	}
+	return o;
+}
+
+int builtin_printf(const char *format, ...)
+{
+	int written;
+	va_list args;
+
+	va_start(args, format);
+	written = builtin_vprintf(format, args);
+	va_end(args);
+
+	return written;
+}
+
+int builtin_fprintf(FILE *stream, const char *format, ...)
+{
+	int written;
+	va_list args;
+
+	va_start(args, format);
+	written = builtin_vfprintf(stream, format, args);
+	va_end(args);
+
+	return written;
+}
+
+int builtin_sprintf(char *str, const char *format, ...)
+{
+	int written;
+	va_list args;
+
+	va_start(args, format);
+	written = builtin_vsnprintf(str, ~(size_t)0, format, args);
+	va_end(args);
+
+	return written;
+}
+
+int builtin_snprintf(char *str, size_t size, const char *format, ...)
+{
+	int written;
+	va_list args;
+
+	va_start(args, format);
+	written = builtin_vsnprintf(str, size, format, args);
+	va_end(args);
+
+	return written;
+}
+
+int builtin_asprintf(char **str, const char *format, ...)
+{
+	int written;
+	va_list args;
+
+	va_start(args, format);
+	written = builtin_vasprintf(str, format, args);
+	va_end(args);
+
+	return written;
+}
+
+int builtin_vprintf(const char *format, va_list ap)
+{
+	return builtin_vfprintf(stdout, format, ap);
+}
+
+int builtin_vfprintf(FILE *stream, const char *format, va_list ap)
+{
+	char buf[PRINTF_BUF_LEN];
+	int len;
+
+	len = builtin_vsnprintf(buf, sizeof(buf), format, ap);
+	return fwrite(buf, 1, len, stream);
+}
+
+int builtin_vsprintf(char *str, const char *format, va_list ap)
+{
+	return builtin_vsnprintf(str, ~(size_t)0, format, ap);
+}
+
+int builtin_vasprintf(char **str, const char *format, va_list ap)
+{
+	char buf[PRINTF_BUF_LEN];
+	int len;
+
+	len = builtin_vsnprintf(buf, sizeof(buf), format, ap);
+	*str = strdup(buf);
+	return len;
+}
+
+METHOD(printf_hook_t, destroy, void,
+	private_printf_hook_t *this)
+{
+	enumerator_t *enumerator;
+	printf_hook_handler_t *handler;
+
+	enumerator = hooks->create_enumerator(hooks);
+	while (enumerator->enumerate(enumerator, NULL, &handler))
+	{
+		free(handler);
+	}
+	enumerator->destroy(enumerator);
+
+	hooks->destroy(hooks);
+
+	free(this);
+}
+
+/*
+ * see header file
+ */
+printf_hook_t *printf_hook_create()
+{
+	private_printf_hook_t *this;
+
+	INIT(this,
+		.public = {
+			.add_handler = _add_handler,
+			.destroy = _destroy,
+		},
+	);
+
+	hooks = hashtable_create(hashtable_hash_ptr, hashtable_equals_ptr, 8);
+
+	return &this->public;
+}
diff --git a/src/libstrongswan/utils/printf_hook/printf_hook_builtin.h b/src/libstrongswan/utils/printf_hook/printf_hook_builtin.h
new file mode 100644
index 000000000..409b5bf3d
--- /dev/null
+++ b/src/libstrongswan/utils/printf_hook/printf_hook_builtin.h
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2013 Martin Willi
+ * Copyright (C) 2013 revosec AG
+ *
+ * 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 printf_hook_builtin printf_hook_builtin
+ * @{ @ingroup utils
+ */
+
+#ifndef PRINTF_HOOK_BUILTIN_H_
+#define PRINTF_HOOK_BUILTIN_H_
+
+#include <stdarg.h>
+#include <stdio.h>
+
+int builtin_printf(const char *format, ...);
+int builtin_fprintf(FILE *stream, const char *format, ...);
+int builtin_sprintf(char *str, const char *format, ...);
+int builtin_snprintf(char *str, size_t size, const char *format, ...);
+int builtin_asprintf(char **str, const char *format, ...);
+
+int builtin_vprintf(const char *format, va_list ap);
+int builtin_vfprintf(FILE *stream, const char *format, va_list ap);
+int builtin_vsprintf(char *str, const char *format, va_list ap);
+int builtin_vsnprintf(char *str, size_t size, const char *format, va_list ap);
+int builtin_vasprintf(char **str, const char *format, va_list ap);
+
+#ifdef printf
+#undef printf
+#endif
+#ifdef fprintf
+#undef fprintf
+#endif
+#ifdef sprintf
+#undef sprintf
+#endif
+#ifdef snprintf
+#undef snprintf
+#endif
+#ifdef asprintf
+#undef asprintf
+#endif
+#ifdef vprintf
+#undef vprintf
+#endif
+#ifdef vfprintf
+#undef vfprintf
+#endif
+#ifdef vsprintf
+#undef vsprintf
+#endif
+#ifdef vsnprintf
+#undef vsnprintf
+#endif
+#ifdef vasprintf
+#undef vasprintf
+#endif
+
+#define printf builtin_printf
+#define fprintf builtin_fprintf
+#define sprintf builtin_sprintf
+#define snprintf builtin_snprintf
+#define asprintf builtin_asprintf
+
+#define vprintf builtin_vprintf
+#define vfprintf builtin_vfprintf
+#define vsprintf builtin_vsprintf
+#define vsnprintf builtin_vsnprintf
+#define vasprintf builtin_vasprintf
+
+#endif /** PRINTF_HOOK_BUILTIN_H_ @}*/