diff --git a/libc/Makefile b/libc/Makefile
index 0e6093d7..5862f749 100644
--- a/libc/Makefile
+++ b/libc/Makefile
@@ -450,6 +450,7 @@ stdlib/clearenv.o \
stdlib/_Exit.o \
stdlib/exit.o \
stdlib/getenv.o \
+stdlib/mkdtemp.o \
stdlib/mkostemp.o \
stdlib/mkostemps.o \
stdlib/mkstemp.o \
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 24da6f0d..183ce1c8 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -105,6 +105,7 @@ void* malloc(size_t);
int mblen(const char*, size_t);
size_t mbstowcs(wchar_t* __restrict, const char* __restrict, size_t);
int mbtowc(wchar_t *__restrict, const char* __restrict, size_t);
+char* mkdtemp(char*);
int mkostemp(char*, int);
int mkostemps(char*, int, int);
int mkstemp(char*);
@@ -161,7 +162,6 @@ long jrand48(unsigned short [3]);
char* l64a(long);
void lcong48(unsigned short [7]);
long lrand48(void);
-char* mkdtemp(char*);
long mrand48(void);
long nrand48(unsigned short[3]);
int posix_memalign(void**, size_t, size_t);
diff --git a/libc/stdlib/mkdtemp.cpp b/libc/stdlib/mkdtemp.cpp
new file mode 100644
index 00000000..b16dec7d
--- /dev/null
+++ b/libc/stdlib/mkdtemp.cpp
@@ -0,0 +1,63 @@
+/*******************************************************************************
+
+ Copyright(C) Jonas 'Sortie' Termansen 2013, 2014, 2015.
+
+ This file is part of the Sortix C Library.
+
+ The Sortix C Library is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or (at your
+ option) any later version.
+
+ The Sortix C Library 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 Lesser General Public
+ License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with the Sortix C Library. If not, see .
+
+ stdlib/mkdtemp.cpp
+ Make a unique temporary directory path and create it.
+
+*******************************************************************************/
+
+#include
+#include
+#include
+#include
+
+const uint32_t NUM_CHARACTERS = 10 + 26 + 26;
+
+static inline char random_character()
+{
+ uint32_t index = arc4random_uniform(NUM_CHARACTERS);
+ if ( index < 10 )
+ return '0' + index;
+ if ( index < 10 + 26 )
+ return 'a' + index - 10;
+ if ( index < 10 + 26 + 26 )
+ return 'A' + index - (10 + 26);
+ __builtin_unreachable();
+}
+
+extern "C" char* mkdtemp(char* templ)
+{
+ size_t templ_length = strlen(templ);
+ if ( templ_length < 6 )
+ return errno = EINVAL, (char*) NULL;
+ size_t xpos = templ_length - 6;
+ for ( size_t i = 0; i < 6; i++ )
+ if ( templ[xpos + i] != 'X' )
+ return errno = EINVAL, (char*) NULL;
+
+ do
+ {
+ for ( size_t i = 0; i < 6; i++ )
+ templ[xpos + i] = random_character();
+ if ( mkdir(templ, 0700) == 0 )
+ return templ;
+ } while ( errno == EEXIST );
+
+ return NULL;
+}