diff --git a/libc/Android.mk b/libc/Android.mk
index e58d4fb..edf834b 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -358,7 +358,7 @@
 #
 libc_static_common_src_files := \
         bionic/__errno.c \
-        bionic/sysconf.c \
+        bionic/sysconf.cpp \
 
 # Architecture specific source files go here
 # =========================================================
diff --git a/libc/bionic/sysconf.cpp b/libc/bionic/sysconf.cpp
new file mode 100644
index 0000000..6555a66
--- /dev/null
+++ b/libc/bionic/sysconf.cpp
@@ -0,0 +1,346 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * 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 COPYRIGHT HOLDERS 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
+ * COPYRIGHT OWNER 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.
+ */
+
+#include <asm/page.h>
+#include <bionic_tls.h>
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdio.h>  // For FOPEN_MAX.
+#include <string.h>
+#include <sys/sysconf.h>
+#include <time.h>
+#include <unistd.h>
+
+/* seems to be the default on Linux, per the GLibc sources and my own digging */
+
+#define  SYSTEM_CLK_TCK         100
+#define  SYSTEM_IOV_MAX         1024
+#define  SYSTEM_DELAYTIMER_MAX  2147483647
+#define  SYSTEM_MQ_OPEN_MAX     8
+#define  SYSTEM_MQ_PRIO_MAX     32768
+#define  SYSTEM_SEM_NSEMS_MAX   256
+#define  SYSTEM_SEM_VALUE_MAX   0x3fffffff  /* see bionic/semaphore.c */
+#define  SYSTEM_SIGQUEUE_MAX    32
+#define  SYSTEM_TIMER_MAX       32
+#define  SYSTEM_LOGIN_NAME_MAX  256
+#define  SYSTEM_TTY_NAME_MAX    32
+
+/* the following depends on our implementation */
+#define  SYSTEM_ATEXIT_MAX          65536    /* our implementation is unlimited */
+#define  SYSTEM_THREAD_KEYS_MAX     BIONIC_TLS_SLOTS
+#define  SYSTEM_THREAD_STACK_MIN    32768    /* lower values may be possible, but be conservative */
+#define  SYSTEM_THREAD_THREADS_MAX  2048     /* really unlimited */
+
+#define  SYSTEM_2_C_BIND     _POSIX_VERSION  /* Posix C binding version */
+#define  SYSTEM_2_C_VER      _POSIX2_C_VERSION
+#define  SYSTEM_2_C_DEV      -1       /* Posix C development tools unsupported on the device */
+#define  SYSTEM_2_FORT_DEV   -1       /* Fortran development unsupported */
+#define  SYSTEM_2_FORT_RUN   -1       /* Fortran runtime unsupported */
+#define  SYSTEM_2_SW_DEV     -1       /* posix software dev utilities unsupported */
+#define  SYSTEM_2_LOCALEDEF  -1       /* localedef() unimplemented */
+#define  SYSTEM_2_UPE        -1       /* No UPE for you ! (User Portability Utilities) */
+#define  SYSTEM_2_VERSION    -1       /* No posix command-line tools */
+
+static bool __matches_cpuN(const char* s) {
+  // The %c trick is to ensure that we have the anchored match "^cpu[0-9]+$".
+  unsigned cpu;
+  char dummy;
+  return (sscanf(s, "cpu%u%c", &cpu, &dummy) == 1);
+}
+
+static int __sysconf_nprocessors_conf() {
+  // On x86 kernels you can use /proc/cpuinfo for this, but on ARM kernels offline CPUs disappear
+  // from there. This method works on both.
+  DIR* d = opendir("/sys/devices/system/cpu");
+  if (!d) {
+    return 1;
+  }
+
+  int result = 0;
+  struct dirent* e;
+  while ((e = readdir(d)) != NULL) {
+    if (e->d_type == DT_DIR && __matches_cpuN(e->d_name)) {
+      ++result;
+    }
+  }
+  closedir(d);
+  return result;
+}
+
+static int __sysconf_nprocessors_onln() {
+  FILE* fp = fopen("/proc/stat", "r");
+  if (fp == NULL) {
+    return 1;
+  }
+
+  int result = 0;
+  char buf[256];
+  while (fgets(buf, sizeof(buf), fp) != NULL) {
+    // Extract just the first word from the line.
+    // 'cpu0 7976751 1364388 3116842 469770388 8629405 0 49047 0 0 0'
+    char* p = strchr(buf, ' ');
+    if (p != NULL) {
+      *p = 0;
+    }
+    if (__matches_cpuN(buf)) {
+      ++result;
+    }
+  }
+  fclose(fp);
+  return result;
+}
+
+static int __get_meminfo(const char* pattern) {
+  FILE* fp = fopen("/proc/meminfo", "r");
+  if (fp == NULL) {
+    return -1;
+  }
+
+  int result = -1;
+  char buf[256];
+  while (fgets(buf, sizeof(buf), fp) != NULL) {
+    long total;
+    if (sscanf(buf, pattern, &total) == 1) {
+      result = (int) (total / (PAGE_SIZE/1024));
+      break;
+    }
+  }
+  fclose(fp);
+  return result;
+}
+
+static int __sysconf_phys_pages() {
+  return __get_meminfo("MemTotal: %ld kB");
+}
+
+static int __sysconf_avphys_pages() {
+  return __get_meminfo("MemFree: %ld kB");
+}
+
+static int __sysconf_monotonic_clock() {
+  timespec t;
+  int rc = clock_getres(CLOCK_MONOTONIC, &t);
+  return (rc == -1) ? -1 : _POSIX_VERSION;
+}
+
+int sysconf(int name) {
+    switch (name) {
+#ifdef _POSIX_ARG_MAX
+    case _SC_ARG_MAX:           return _POSIX_ARG_MAX;
+#endif
+#ifdef _POSIX2_BC_BASE_MAX
+    case _SC_BC_BASE_MAX:       return _POSIX2_BC_BASE_MAX;
+#endif
+#ifdef _POSIX2_BC_DIM_MAX
+    case _SC_BC_DIM_MAX:        return _POSIX2_BC_DIM_MAX;
+#endif
+#ifdef _POSIX2_BC_SCALE_MAX
+    case _SC_BC_SCALE_MAX:      return _POSIX2_BC_SCALE_MAX;
+#endif
+#ifdef _POSIX2_BC_STRING_MAX
+    case _SC_BC_STRING_MAX:     return _POSIX2_BC_STRING_MAX;
+#endif
+    case _SC_CHILD_MAX:         return CHILD_MAX;
+    case _SC_CLK_TCK:           return SYSTEM_CLK_TCK;
+#ifdef _POSIX2_COLL_WEIGHTS_MASK
+    case _SC_COLL_WEIGHTS_MAX:  return _POSIX2_COLL_WEIGHTS_MASK;
+#endif
+#ifdef _POSIX2_EXPR_NEST_MAX
+    case _SC_EXPR_NEST_MAX:    return _POSIX2_EXPR_NEST_MAX;
+#endif
+#ifdef _POSIX2_LINE_MAX
+    case _SC_LINE_MAX:          return _POSIX2_LINE_MAX;
+#endif
+    case _SC_NGROUPS_MAX:       return NGROUPS_MAX;
+    case _SC_OPEN_MAX:          return OPEN_MAX;
+    //case _SC_PASS_MAX:          return PASS_MAX;
+    case _SC_2_C_BIND:          return SYSTEM_2_C_BIND;
+    case _SC_2_C_DEV:           return SYSTEM_2_C_DEV;
+    case _SC_2_C_VERSION:       return SYSTEM_2_C_VER;
+    //case _SC_2_CHAR_TERM:         return ;
+    case _SC_2_FORT_DEV:        return SYSTEM_2_FORT_DEV;
+    case _SC_2_FORT_RUN:        return SYSTEM_2_FORT_RUN;
+    case _SC_2_LOCALEDEF:       return SYSTEM_2_LOCALEDEF;
+    case _SC_2_SW_DEV:          return SYSTEM_2_SW_DEV;
+    case _SC_2_UPE:             return SYSTEM_2_UPE;
+    case _SC_2_VERSION:         return SYSTEM_2_VERSION;
+#ifdef _POSIX_JOB_CONTROL
+    case _SC_JOB_CONTROL:       return _POSIX_JOB_CONTROL;
+#endif
+#ifdef _POSIX_SAVED_IDS
+    case _SC_SAVED_IDS:         return _POSIX_SAVED_IDS;
+#endif
+#ifdef _POSIX_VERSION
+    case _SC_VERSION:           return _POSIX_VERSION;
+#endif
+    //case _SC_RE_DUP_<AX:        return ;
+    case _SC_STREAM_MAX:        return FOPEN_MAX;
+    //case _SC_TZNAME_MAX:        return ;
+#if _XOPEN_CRYPT
+    case _SC_XOPEN_CRYPT:       return _XOPEN_CRYPT;
+#endif
+#ifdef _XOPEN_ENH_I18N
+    case _SC_XOPEN_ENH_I18N:    return _XOPEN_ENH_I18N;
+#endif
+#ifdef _XOPEN_SHM
+    case _SC_XOPEN_SHM:         return _XOPEN_SHM;
+#endif
+#ifdef _XOPEN_VERSION
+    case _SC_XOPEN_VERSION:     return _XOPEN_VERSION;
+#endif
+#ifdef _XOPEN_XCU_VERSION
+    case _SC_XOPEN_XCU_VERSION: return _XOPEN_XCU_VERSION;
+#endif
+#ifdef _XOPEN_REALTIME
+    case _SC_XOPEN_REALTIME:    return _XOPEN_REALTIME;
+#endif
+#ifdef _XOPEN_REALTIME_THREADS
+    case _SC_XOPEN_REALTIME_THREADS: return _XOPEN_REALTIME_THREADS;
+#endif
+#ifdef _XOPEN_LEGACY
+    case _SC_XOPEN_LEGACY:      return _XOPEN_LEGACY;
+#endif
+    case _SC_ATEXIT_MAX:        return SYSTEM_ATEXIT_MAX;
+    case _SC_IOV_MAX:           return SYSTEM_IOV_MAX;
+    case _SC_PAGESIZE:          return PAGE_SIZE;
+    case _SC_PAGE_SIZE:         return PAGE_SIZE;
+#ifdef _XOPEN_UNIX
+    case _SC_XOPEN_UNIX:        return _XOPEN_UNIX;
+#endif
+
+    // XXX: TODO: XBS5 nonsense
+
+#ifdef AIO_LISTIO_MAX
+    case _SC_AIO_LISTIO_MAX:       return AIO_LISTIO_MAX;
+#endif
+#ifdef AIO_MAX
+    case _SC_AIO_MAX:              return AIO_MAX;
+#endif
+#ifdef AIO_PRIO_DELTA_MAX
+    case _SC_AIO_PRIO_DELTA_MAX:   return AIO_PRIO_DELTA_MAX;
+#endif
+    case _SC_DELAYTIMER_MAX:    return SYSTEM_DELAYTIMER_MAX;
+    case _SC_MQ_OPEN_MAX:       return SYSTEM_MQ_OPEN_MAX;
+    case _SC_MQ_PRIO_MAX:       return SYSTEM_MQ_PRIO_MAX;
+    case _SC_RTSIG_MAX:         return RTSIG_MAX;
+    case _SC_SEM_NSEMS_MAX:     return SYSTEM_SEM_NSEMS_MAX;
+    case _SC_SEM_VALUE_MAX:     return SYSTEM_SEM_VALUE_MAX;
+    case _SC_SIGQUEUE_MAX:      return SYSTEM_SIGQUEUE_MAX;
+    case _SC_TIMER_MAX:         return SYSTEM_TIMER_MAX;
+#ifdef _POSIX_ASYNCHRONOUS_IO
+    case _SC_ASYNCHRONOUS_IO:   return _POSIX_ASYNCHRONOUS_IO;
+#endif
+#ifdef _POSIX_FSYNC
+    case _SC_FSYNC:             return _POSIX_FSYNC;
+#endif
+#ifdef _POSIX_MAPPED_FILES
+    case _SC_MAPPED_FILES:      return _POSIX_MAPPED_FILES;
+#endif
+#ifdef _POSIX_MEMLOCK
+    case _SC_MEMLOCK:           return _POSIX_MEMLOCK;
+#endif
+#ifdef _POSIX_MEMLOCK_RANGE
+    case _SC_MEMLOCK_RANGE:     return _POSIX_MEMLOCK_RANGE
+#endif
+#ifdef _POSIX_MEMORY_PROTECTION
+    case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION;
+#endif
+#ifdef _POSIX_MESSAGE_PASSING
+    case _SC_MESSAGE_PASSING:   return _POSIX_MESSAGE_PASSING;
+#endif
+#ifdef _POSIX_PRIORITIZED_IO
+    case _SC_PRIORITIZED_IO:    return _POSIX_PRIORITIZED_IO;
+#endif
+#ifdef _POSIX_PRIORITY_SCHEDULING
+    case _SC_PRIORITY_SCHEDULING:  return _POSIX_PRIORITY_SCHEDULING;
+#endif
+#ifdef _POSIX_REALTIME_SIGNALS
+    case _SC_REALTIME_SIGNALS:  return _POSIX_REALTIME_SIGNALS;
+#endif
+#ifdef _POSIX_SEMAPHORES
+    case _SC_SEMAPHORES:        return _POSIX_SEMAPHORES;
+#endif
+#ifdef _POSIX_SHARED_MEMORY_OBJECTS
+    case _SC_SHARED_MEMORY_OBJECTS:  return _POSIX_SHARED_MEMORY_OBJECTS;
+#endif
+#ifdef _POSIX_SYNCHRONIZED_IO
+    case _SC_SYNCHRONIZED_IO:   return _POSIX_SYNCHRONIZED_IO;
+#endif
+#ifdef _POSIX_TIMERS
+    case _SC_TIMERS:            return _POSIX_TIMERS;
+#endif
+
+    // GETGR_R_SIZE_MAX ?
+    // GETPW_R_SIZE_MAX ?
+
+    case _SC_LOGIN_NAME_MAX:    return SYSTEM_LOGIN_NAME_MAX;
+#ifdef _POSIX_THREAD_DESTRUCTOR_ITERATIONS
+    case _SC_THREAD_DESTRUCTOR_ITERATIONS:  return _POSIX_THREAD_DESTRUCTOR_ITERATIONS;
+#endif
+    case _SC_THREAD_KEYS_MAX:     return SYSTEM_THREAD_KEYS_MAX;
+    case _SC_THREAD_STACK_MIN:    return SYSTEM_THREAD_STACK_MIN;
+    case _SC_THREAD_THREADS_MAX:  return SYSTEM_THREAD_THREADS_MAX;
+    case _SC_TTY_NAME_MAX:        return SYSTEM_TTY_NAME_MAX;
+#ifdef _POSIX_THREADS
+    case _SC_THREADS:             return _POSIX_THREADS;
+#endif
+#ifdef _POSIX_THREAD_ATTR_STACKADDR
+    case _SC_THREAD_ATTR_STACKADDR:   return _POSIX_THREAD_ATTR_STACKADDR;
+#endif
+#ifdef _POSIX_THREAD_ATTR_STACKSIZE
+    case _SC_THREAD_ATTR_STACKSIZE:   return _POSIX_THREAD_ATTR_STACKSIZE;
+#endif
+#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
+    case _SC_THREAD_PRIORITY_SCHEDULING:  return _POSIX_THREAD_PRIORITY_SCHEDULING;
+#endif
+#ifdef _POSIX_THREAD_PRIO_INHERIT
+    case _SC_THREAD_PRIO_INHERIT:         return _POSIX_THREAD_PRIO_INHERIT;
+#endif
+#ifdef _POSIX_THREAD_PRIO_PROTECT
+    case _SC_THREAD_PRIO_PROTECT: return _POSIX_THREAD_PRIO_PROTECT;
+#endif
+#ifdef _POSIX_THREAD_SAFE_FUNCTIONS
+    case _SC_THREAD_SAFE_FUNCTIONS:  return _POSIX_THREAD_SAFE_FUNCTIONS
+#endif
+
+    case _SC_MONOTONIC_CLOCK:   return __sysconf_monotonic_clock();
+    case _SC_NPROCESSORS_CONF:  return __sysconf_nprocessors_conf();
+    case _SC_NPROCESSORS_ONLN:  return __sysconf_nprocessors_onln();
+    case _SC_PHYS_PAGES:        return __sysconf_phys_pages();
+    case _SC_AVPHYS_PAGES:      return __sysconf_avphys_pages();
+
+    default:
+       /* Posix says EINVAL is the only error that shall be returned,
+        * but GLibc uses ENOSYS */
+        errno = ENOSYS;
+        return -1;
+    }
+}
diff --git a/libc/include/sys/limits.h b/libc/include/sys/limits.h
index 41d02ff..5b127eb 100644
--- a/libc/include/sys/limits.h
+++ b/libc/include/sys/limits.h
@@ -169,7 +169,8 @@
 
 #undef   _POSIX_PROCESS_SHARED           /* we don't support process-shared synchronization */
 #undef   _POSIX_THREAD_SAFE_FUNCTIONS    /* most functions are, but not everything yet */
-#define  _POSIX_CHOWN_RESTRICTED    1    /* yes, chown requires appropriate priviledges */
+#define  _POSIX_CHOWN_RESTRICTED    1    /* yes, chown requires appropriate privileges */
+#define  _POSIX_MONOTONIC_CLOCK     0    /* the monotonic clock may be available; ask sysconf */
 #define  _POSIX_NO_TRUNC            1    /* very long pathnames generate an error */
 #define  _POSIX_SAVED_IDS           1    /* saved user ids is a Linux feature */
 #define  _POSIX_JOB_CONTROL         1    /* job control is a Linux feature */
diff --git a/libc/include/sys/sysconf.h b/libc/include/sys/sysconf.h
index 2fc1b08..0a46e7a 100644
--- a/libc/include/sys/sysconf.h
+++ b/libc/include/sys/sysconf.h
@@ -127,8 +127,9 @@
 #define _SC_NPROCESSORS_ONLN            0x0061
 #define _SC_PHYS_PAGES                  0x0062
 #define _SC_AVPHYS_PAGES                0x0063
+#define _SC_MONOTONIC_CLOCK             0x0064
 
-extern int sysconf (int  name);
+extern int sysconf(int name);
 
 __END_DECLS
 
diff --git a/tests/Android.mk b/tests/Android.mk
index 7153383..083bb70 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -65,6 +65,7 @@
     stdlib_test.cpp \
     string_test.cpp \
     stubs_test.cpp \
+    unistd_test.cpp \
 
 test_dynamic_ldflags = -Wl,--export-dynamic -Wl,-u,DlSymTestFunction
 test_dynamic_src_files = \
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
new file mode 100644
index 0000000..a9dd5d2
--- /dev/null
+++ b/tests/unistd_test.cpp
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <unistd.h>
+
+TEST(unistd, sysconf_SC_MONOTONIC_CLOCK) {
+  ASSERT_GT(sysconf(_SC_MONOTONIC_CLOCK), 0);
+}