diff --git a/libc/bionic/sysconf.cpp b/libc/bionic/sysconf.cpp
index 2df6acc..67f48e7 100644
--- a/libc/bionic/sysconf.cpp
+++ b/libc/bionic/sysconf.cpp
@@ -29,8 +29,10 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
+#include <linux/uio.h>  // For UIO_MAXIOV.
 #include <pthread.h>
 #include <stdio.h>  // For FOPEN_MAX.
+#include <sys/auxv.h>
 #include <sys/sysconf.h>
 #include <sys/sysinfo.h>
 #include <time.h>
@@ -38,33 +40,6 @@
 
 #include "private/bionic_tls.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_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_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 int __sysconf_monotonic_clock() {
   timespec t;
   int rc = clock_getres(CLOCK_MONOTONIC, &t);
@@ -73,103 +48,135 @@
 
 long sysconf(int name) {
   switch (name) {
-    case _SC_ARG_MAX:           return _POSIX_ARG_MAX;
+    case _SC_ARG_MAX:           return ARG_MAX;
+    case _SC_BC_BASE_MAX:       return _POSIX2_BC_BASE_MAX;   // Minimum requirement.
+    case _SC_BC_DIM_MAX:        return _POSIX2_BC_DIM_MAX;    // Minimum requirement.
+    case _SC_BC_SCALE_MAX:      return _POSIX2_BC_SCALE_MAX;  // Minimum requirement.
+    case _SC_BC_STRING_MAX:     return _POSIX2_BC_STRING_MAX; // Minimum requirement.
     case _SC_CHILD_MAX:         return CHILD_MAX;
-    case _SC_CLK_TCK:           return SYSTEM_CLK_TCK;
-    case _SC_LINE_MAX:          return _POSIX2_LINE_MAX;
+    case _SC_CLK_TCK:           return static_cast<long>(getauxval(AT_CLKTCK));
+    case _SC_COLL_WEIGHTS_MAX:  return _POSIX2_COLL_WEIGHTS_MAX;  // Minimum requirement.
+    case _SC_EXPR_NEST_MAX:     return _POSIX2_EXPR_NEST_MAX;     // Minimum requirement.
+    case _SC_LINE_MAX:          return _POSIX2_LINE_MAX;          // Minimum requirement.
     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;
+    case _SC_2_C_BIND:          return _POSIX2_C_BIND;
+    case _SC_2_C_DEV:           return _POSIX2_C_DEV;
+    case _SC_2_CHAR_TERM:       return _POSIX2_CHAR_TERM;
+    case _SC_2_FORT_DEV:        return -1;
+    case _SC_2_FORT_RUN:        return -1;
+    case _SC_2_LOCALEDEF:       return _POSIX2_LOCALEDEF;
+    case _SC_2_SW_DEV:          return _POSIX2_SW_DEV;
+    case _SC_2_UPE:             return _POSIX2_UPE;
+    case _SC_2_VERSION:         return _POSIX2_VERSION;
     case _SC_JOB_CONTROL:       return _POSIX_JOB_CONTROL;
     case _SC_SAVED_IDS:         return _POSIX_SAVED_IDS;
     case _SC_VERSION:           return _POSIX_VERSION;
-    case _SC_RE_DUP_MAX:        return _POSIX_RE_DUP_MAX;
+    case _SC_RE_DUP_MAX:        return _POSIX_RE_DUP_MAX;         // Minimum requirement.
     case _SC_STREAM_MAX:        return FOPEN_MAX;
-    case _SC_TZNAME_MAX:        return _POSIX_TZNAME_MAX;
+    case _SC_TZNAME_MAX:        return _POSIX_TZNAME_MAX;         // Minimum requirement.
     case _SC_XOPEN_CRYPT:       return _XOPEN_CRYPT;
     case _SC_XOPEN_ENH_I18N:    return _XOPEN_ENH_I18N;
-    //case _SC_XOPEN_SHM:         return _XOPEN_SHM;
+    case _SC_XOPEN_SHM:         return _XOPEN_SHM;
     case _SC_XOPEN_VERSION:     return _XOPEN_VERSION;
-    case _SC_XOPEN_XCU_VERSION: return _XOPEN_XCU_VERSION;
     case _SC_XOPEN_REALTIME:    return _XOPEN_REALTIME;
     case _SC_XOPEN_REALTIME_THREADS: return _XOPEN_REALTIME_THREADS;
     case _SC_XOPEN_LEGACY:      return _XOPEN_LEGACY;
-    case _SC_ATEXIT_MAX:        return SYSTEM_ATEXIT_MAX;
-    case _SC_IOV_MAX:           return SYSTEM_IOV_MAX;
+    case _SC_ATEXIT_MAX:        return LONG_MAX;    // Unlimited.
+    case _SC_IOV_MAX:           return UIO_MAXIOV;
 
-    case _SC_PAGESIZE:
-    case _SC_PAGE_SIZE:
-        return PAGE_SIZE;
-
+    case _SC_PAGESIZE:          // Fall through, PAGESIZE and PAGE_SIZE always hold the same value.
+    case _SC_PAGE_SIZE:         return PAGE_SIZE;
     case _SC_XOPEN_UNIX:        return _XOPEN_UNIX;
-
-    // XXX: TODO: XBS5 nonsense
-
-    //case _SC_AIO_LISTIO_MAX:       return AIO_LISTIO_MAX;
-    //case _SC_AIO_MAX:              return AIO_MAX;
-    //case _SC_AIO_PRIO_DELTA_MAX:   return AIO_PRIO_DELTA_MAX;
-    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_AIO_LISTIO_MAX:    return _POSIX_AIO_LISTIO_MAX;     // Minimum requirement.
+    case _SC_AIO_MAX:           return _POSIX_AIO_MAX;            // Minimum requirement.
+    case _SC_AIO_PRIO_DELTA_MAX:return 0;                         // Minimum requirement.
+    case _SC_DELAYTIMER_MAX:    return INT_MAX;
+    case _SC_MQ_OPEN_MAX:       return _POSIX_MQ_OPEN_MAX;        // Minimum requirement.
+    case _SC_MQ_PRIO_MAX:       return _POSIX_MQ_PRIO_MAX;        // Minimum requirement.
     case _SC_RTSIG_MAX:         return RTSIG_MAX;
-    case _SC_SEM_NSEMS_MAX:     return SYSTEM_SEM_NSEMS_MAX;
+    case _SC_SEM_NSEMS_MAX:     return _POSIX_SEM_NSEMS_MAX;      // Minimum requirement.
     case _SC_SEM_VALUE_MAX:     return SEM_VALUE_MAX;
-    case _SC_SIGQUEUE_MAX:      return SYSTEM_SIGQUEUE_MAX;
-    case _SC_TIMER_MAX:         return SYSTEM_TIMER_MAX;
-    //case _SC_ASYNCHRONOUS_IO:   return _POSIX_ASYNCHRONOUS_IO;
+    case _SC_SIGQUEUE_MAX:      return _POSIX_SIGQUEUE_MAX;       // Minimum requirement.
+    case _SC_TIMER_MAX:         return _POSIX_TIMER_MAX;          // Minimum requirement.
+    case _SC_ASYNCHRONOUS_IO:   return _POSIX_ASYNCHRONOUS_IO;
     case _SC_FSYNC:             return _POSIX_FSYNC;
     case _SC_MAPPED_FILES:      return _POSIX_MAPPED_FILES;
-    //case _SC_MEMLOCK:           return _POSIX_MEMLOCK;
-    //case _SC_MEMLOCK_RANGE:     return _POSIX_MEMLOCK_RANGE;
-    //case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION;
-    //case _SC_MESSAGE_PASSING:   return _POSIX_MESSAGE_PASSING;
-    //case _SC_PRIORITIZED_IO:    return _POSIX_PRIORITIZED_IO;
+    case _SC_MEMLOCK:           return _POSIX_MEMLOCK;
+    case _SC_MEMLOCK_RANGE:     return _POSIX_MEMLOCK_RANGE;
+    case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION;
+    case _SC_MESSAGE_PASSING:   return _POSIX_MESSAGE_PASSING;
+    case _SC_PRIORITIZED_IO:    return _POSIX_PRIORITIZED_IO;
     case _SC_PRIORITY_SCHEDULING:  return _POSIX_PRIORITY_SCHEDULING;
     case _SC_REALTIME_SIGNALS:  return _POSIX_REALTIME_SIGNALS;
     case _SC_SEMAPHORES:        return _POSIX_SEMAPHORES;
-    //case _SC_SHARED_MEMORY_OBJECTS:  return _POSIX_SHARED_MEMORY_OBJECTS;
+    case _SC_SHARED_MEMORY_OBJECTS:  return _POSIX_SHARED_MEMORY_OBJECTS;
     case _SC_SYNCHRONIZED_IO:   return _POSIX_SYNCHRONIZED_IO;
     case _SC_TIMERS:            return _POSIX_TIMERS;
-
-    case _SC_GETGR_R_SIZE_MAX: return 1024;
-    case _SC_GETPW_R_SIZE_MAX: return 1024;
-
-    case _SC_LOGIN_NAME_MAX:    return SYSTEM_LOGIN_NAME_MAX;
-
-    case _SC_THREAD_DESTRUCTOR_ITERATIONS:
-      return _POSIX_THREAD_DESTRUCTOR_ITERATIONS;
-
-    case _SC_THREAD_KEYS_MAX:
-      return (BIONIC_TLS_SLOTS - TLS_SLOT_FIRST_USER_SLOT - BIONIC_TLS_RESERVED_SLOTS);
-
+    case _SC_GETGR_R_SIZE_MAX:  return 1024;
+    case _SC_GETPW_R_SIZE_MAX:  return 1024;
+    case _SC_LOGIN_NAME_MAX:    return 256;   // Seems default on linux.
+    case _SC_THREAD_DESTRUCTOR_ITERATIONS: return PTHREAD_DESTRUCTOR_ITERATIONS;
+    case _SC_THREAD_KEYS_MAX:   return PTHREAD_KEYS_MAX;
     case _SC_THREAD_STACK_MIN:    return PTHREAD_STACK_MIN;
-    case _SC_THREAD_THREADS_MAX:  return SYSTEM_THREAD_THREADS_MAX;
-    case _SC_TTY_NAME_MAX:        return SYSTEM_TTY_NAME_MAX;
+    case _SC_THREAD_THREADS_MAX:  return PTHREAD_THREADS_MAX;
+    case _SC_TTY_NAME_MAX:        return 32;  // Seems default on linux.
     case _SC_THREADS:             return _POSIX_THREADS;
-
-    case _SC_THREAD_ATTR_STACKADDR:   return -1; // Removed in POSIX 2008
-    case _SC_THREAD_ATTR_STACKSIZE:   return -1; // Removed in POSIX 2008
-
-    //case _SC_THREAD_PRIORITY_SCHEDULING:  return _POSIX_THREAD_PRIORITY_SCHEDULING;
-    case _SC_THREAD_PRIO_INHERIT:         return _POSIX_THREAD_PRIO_INHERIT;
+    case _SC_THREAD_ATTR_STACKADDR:   return _POSIX_THREAD_ATTR_STACKADDR;
+    case _SC_THREAD_ATTR_STACKSIZE:   return _POSIX_THREAD_ATTR_STACKSIZE;
+    case _SC_THREAD_PRIORITY_SCHEDULING:  return _POSIX_THREAD_PRIORITY_SCHEDULING;
+    case _SC_THREAD_PRIO_INHERIT: return _POSIX_THREAD_PRIO_INHERIT;
     case _SC_THREAD_PRIO_PROTECT: return _POSIX_THREAD_PRIO_PROTECT;
-    //case _SC_THREAD_SAFE_FUNCTIONS:  return _POSIX_THREAD_SAFE_FUNCTIONS
-
-    case _SC_MONOTONIC_CLOCK:   return __sysconf_monotonic_clock();
+    case _SC_THREAD_SAFE_FUNCTIONS:  return _POSIX_THREAD_SAFE_FUNCTIONS;
     case _SC_NPROCESSORS_CONF:  return get_nprocs_conf();
     case _SC_NPROCESSORS_ONLN:  return get_nprocs();
     case _SC_PHYS_PAGES:        return get_phys_pages();
     case _SC_AVPHYS_PAGES:      return get_avphys_pages();
+    case _SC_MONOTONIC_CLOCK:   return __sysconf_monotonic_clock();
+
+    case _SC_2_PBS:             return -1;     // Obsolescent in POSIX.1-2008.
+    case _SC_2_PBS_ACCOUNTING:  return -1;     // Obsolescent in POSIX.1-2008.
+    case _SC_2_PBS_CHECKPOINT:  return -1;     // Obsolescent in POSIX.1-2008.
+    case _SC_2_PBS_LOCATE:      return -1;     // Obsolescent in POSIX.1-2008.
+    case _SC_2_PBS_MESSAGE:     return -1;     // Obsolescent in POSIX.1-2008.
+    case _SC_2_PBS_TRACK:       return -1;     // Obsolescent in POSIX.1-2008.
+    case _SC_ADVISORY_INFO:     return _POSIX_ADVISORY_INFO;
+    case _SC_BARRIERS:          return _POSIX_BARRIERS;
+    case _SC_CLOCK_SELECTION:   return _POSIX_CLOCK_SELECTION;
+    case _SC_CPUTIME:           return _POSIX_CPUTIME;
+    case _SC_HOST_NAME_MAX:     return _POSIX_HOST_NAME_MAX;    // Minimum requirement.
+    case _SC_IPV6:              return _POSIX_IPV6;
+    case _SC_RAW_SOCKETS:       return _POSIX_RAW_SOCKETS;
+    case _SC_READER_WRITER_LOCKS: return _POSIX_READER_WRITER_LOCKS;
+    case _SC_REGEXP:            return _POSIX_REGEXP;
+    case _SC_SHELL:             return _POSIX_SHELL;
+    case _SC_SPAWN:             return _POSIX_SPAWN;
+    case _SC_SPIN_LOCKS:        return _POSIX_SPIN_LOCKS;
+    case _SC_SPORADIC_SERVER:   return _POSIX_SPORADIC_SERVER;
+    case _SC_SS_REPL_MAX:       return -1;
+    case _SC_SYMLOOP_MAX:       return _POSIX_SYMLOOP_MAX;      // Minimum requirement.
+    case _SC_THREAD_CPUTIME:    return _POSIX_THREAD_CPUTIME;
+    case _SC_THREAD_PROCESS_SHARED: return _POSIX_THREAD_PROCESS_SHARED;
+    case _SC_THREAD_ROBUST_PRIO_INHERIT:  return _POSIX_THREAD_ROBUST_PRIO_INHERIT;
+    case _SC_THREAD_ROBUST_PRIO_PROTECT:  return _POSIX_THREAD_ROBUST_PRIO_PROTECT;
+    case _SC_THREAD_SPORADIC_SERVER:      return _POSIX_THREAD_SPORADIC_SERVER;
+    case _SC_TIMEOUTS:          return _POSIX_TIMEOUTS;
+    case _SC_TRACE:             return -1;             // Obsolescent in POSIX.1-2008.
+    case _SC_TRACE_EVENT_FILTER:      return -1;       // Obsolescent in POSIX.1-2008.
+    case _SC_TRACE_EVENT_NAME_MAX:    return -1;
+    case _SC_TRACE_INHERIT:     return -1;             // Obsolescent in POSIX.1-2008.
+    case _SC_TRACE_LOG:         return -1;             // Obsolescent in POSIX.1-2008.
+    case _SC_TRACE_NAME_MAX:    return -1;
+    case _SC_TRACE_SYS_MAX:     return -1;
+    case _SC_TRACE_USER_EVENT_MAX:    return -1;
+    case _SC_TYPED_MEMORY_OBJECTS:    return _POSIX_TYPED_MEMORY_OBJECTS;
+    case _SC_V7_ILP32_OFF32:    return _POSIX_V7_ILP32_OFF32;
+    case _SC_V7_ILP32_OFFBIG:   return _POSIX_V7_ILP32_OFFBIG;
+    case _SC_V7_LP64_OFF64:     return _POSIX_V7_LP64_OFF64;
+    case _SC_V7_LPBIG_OFFBIG:   return _POSIX_V7_LPBIG_OFFBIG;
+    case _SC_XOPEN_STREAMS:     return -1;            // Obsolescent in POSIX.1-2008.
+    case _SC_XOPEN_UUCP:        return -1;
 
     default:
       // Posix says EINVAL is the only error that shall be returned,
diff --git a/libc/include/machine/posix_limits.h b/libc/include/machine/posix_limits.h
index f092731..e5a299b 100644
--- a/libc/include/machine/posix_limits.h
+++ b/libc/include/machine/posix_limits.h
@@ -29,46 +29,129 @@
 #ifndef _POSIX_LIMITS_H_
 #define _POSIX_LIMITS_H_
 
-/* TODO: complete and check these. */
-#define _POSIX2_LINE_MAX            2048
-#define _POSIX2_RE_DUP_MAX          _POSIX_RE_DUP_MAX
+
+/* Any constant values here other than -1 or 200809L are explicitly specified by POSIX.1-2008. */
+/* Keep it sorted. */
+#define _POSIX_ADVISORY_INFO        -1  /* posix_madvise() not implemented */
+#define _POSIX_AIO_LISTIO_MAX       2
+#define _POSIX_AIO_MAX              1
 #define _POSIX_ARG_MAX              4096
+#define _POSIX_ASYNCHRONOUS_IO      -1  /* not implemented */
+#define _POSIX_BARRIERS             -1  /* not implemented */
 #define _POSIX_CHILD_MAX            25
 #define _POSIX_CHOWN_RESTRICTED     1  /* yes, chown requires appropriate privileges */
-#define _POSIX_FSYNC                1  /* fdatasync() supported */
-#define _POSIX_JOB_CONTROL          1  /* job control is a Linux feature */
+#define _POSIX_CLOCK_SELECTION      200809L
+#define _POSIX_CPUTIME              -1  /* clock_getcpuclockid() not implemented */
+#define _POSIX_DELAYTIMER_MAX       32
+#define _POSIX_FSYNC                200809L  /* fdatasync() supported */
 #define _POSIX_HOST_NAME_MAX        255
+#define _POSIX_IPV6                 200809L
+#define _POSIX_JOB_CONTROL          1  /* job control is a Linux feature */
 #define _POSIX_LINK_MAX             8
 #define _POSIX_LOGIN_NAME_MAX       9  /* includes trailing NUL */
-#define _POSIX_MAPPED_FILES         1  /* mmap-ed files supported */
+#define _POSIX_MAPPED_FILES         200809L  /* mmap-ed files supported */
 #define _POSIX_MAX_CANON            255
 #define _POSIX_MAX_INPUT            255
+#define _POSIX_MEMLOCK              200809L
+#define _POSIX_MEMLOCK_RANGE        200809L
+#define _POSIX_MEMORY_PROTECTION    200809L
+#define _POSIX_MESSAGE_PASSING      -1  /* not implemented */
 #define _POSIX_MONOTONIC_CLOCK      0  /* the monotonic clock may be available; ask sysconf */
+#define _POSIX_MQ_OPEN_MAX          8
+#define _POSIX_MQ_PRIO_MAX          32
 #define _POSIX_NAME_MAX             14
-#define _POSIX_NGROUPS_MAX          0
+#define _POSIX_NGROUPS_MAX          8
 #define _POSIX_NO_TRUNC             1  /* very long pathnames generate an error */
-#define _POSIX_OPEN_MAX             16
+#define _POSIX_OPEN_MAX             20
 #define _POSIX_PATH_MAX             256
 #define _POSIX_PIPE_BUF             512
-#define _POSIX_PRIORITY_SCHEDULING  1  /* priority scheduling is a Linux feature */
+#define _POSIX_PRIORITY_SCHEDULING  200809L  /* priority scheduling is a Linux feature */
+#define _POSIX_PRIORITIZED_IO       -1  /* not implemented */
+#define _POSIX_RAW_SOCKETS          200809L
+#define _POSIX_READER_WRITER_LOCKS  200809L
 #define _POSIX_REALTIME_SIGNALS     -1 /* for now, this is not supported */
+#define _POSIX_REGEXP               1
 #define _POSIX_RE_DUP_MAX           255
 #define _POSIX_SAVED_IDS            1  /* saved user ids is a Linux feature */
 #define _POSIX_SEMAPHORES           200809L
+#define _POSIX_SEM_NSEMS_MAX        256
 #define _POSIX_SEM_VALUE_MAX        32767
+#define _POSIX_SHARED_MEMORY_OBJECTS  -1  /* shm_open()/shm_unlink() not implemented */
+#define _POSIX_SHELL                1   /* system() supported */
+#define _POSIX_SIGQUEUE_MAX         32
+#define _POSIX_SPAWN                -1  /* not implemented */
+#define _POSIX_SPIN_LOCKS           -1  /* not implemented */
+#define _POSIX_SPORADIC_SERVER      -1  /* not implemented */
 #define _POSIX_SSIZE_MAX            32767
 #define _POSIX_STREAM_MAX           8
 #define _POSIX_SYMLINK_MAX          255
 #define _POSIX_SYMLOOP_MAX          8
-#define _POSIX_SYNCHRONIZED_IO      1  /* synchronized i/o supported */
-#define _POSIX_THREAD_PRIO_INHERIT  200112L  /* linux feature */
-#define _POSIX_THREAD_PRIO_PROTECT  200112L  /* linux feature */
-#define _POSIX_THREADS              1  /* we support threads */
-#define _POSIX_THREAD_STACKADDR     1  /* we support thread stack address */
-#define _POSIX_THREAD_STACKSIZE     1  /* we support thread stack size */
-#define _POSIX_TIMERS               1  /* Posix timers are supported */
+#define _POSIX_SYNCHRONIZED_IO      200809L  /* synchronized i/o supported */
+#define _POSIX_THREADS              200809L  /* we support threads */
+#define _POSIX_THREAD_ATTR_STACKADDR  200809L
+#define _POSIX_THREAD_ATTR_STACKSIZE  200809L
+#define _POSIX_THREAD_CPUTIME       200809L
+#define _POSIX_THREAD_DESTRUCTOR_ITERATIONS 4
+#define _POSIX_THREAD_KEYS_MAX      128
+#define _POSIX_THREAD_PRIORITY_SCHEDULING 200809L
+#define _POSIX_THREAD_PRIO_INHERIT  200809L  /* linux feature */
+#define _POSIX_THREAD_PRIO_PROTECT  200809L  /* linux feature */
+#define _POSIX_THREAD_PROCESS_SHARED  -1  /* not implemented */
+#define _POSIX_THREAD_ROBUST_PRIO_INHERIT -1  /* not implemented */
+#define _POSIX_THREAD_ROBUST_PRIO_PROTECT -1  /* not implemented */
+#define _POSIX_THREAD_SAFE_FUNCTIONS 200809L
+#define _POSIX_THREAD_SPORADIC_SERVER -1  /* not implemented */
+#define _POSIX_THREAD_THREADS_MAX   64
+#define _POSIX_TIMEOUTS             200809L
+#define _POSIX_TIMERS               200809L  /* Posix timers are supported */
+#define _POSIX_TIMER_MAX            32
+#define _POSIX_TRACE                -1  /* not implemented */
+#define _POSIX_TRACE_EVENT_FILTER   -1  /* not implemented */
+#define _POSIX_TRACE_INHERIT        -1  /* not implemented */
+#define _POSIX_TRACE_LOG            -1  /* not implemented */
+#define _POSIX_TRACE_NAME_MAX       8
+#define _POSIX_TRACE_SYS_MAX        8
+#define _POSIX_TRACE_USER_EVENT_MAX 32
 #define _POSIX_TTY_NAME_MAX         9  /* includes trailing NUL */
-#define _POSIX_TZNAME_MAX           3
+#define _POSIX_TYPED_MEMORY_OBJECTS -1  /* not implemented */
+#define _POSIX_TZNAME_MAX           6
 #define _POSIX_VDISABLE             '\0'
 
+#if defined(__LP64__)
+#define _POSIX_V7_ILP32_OFF32       -1
+#define _POSIX_V7_ILP32_OFFBIG      -1
+#define _POSIX_V7_LP64_OFF64         1
+#define _POSIX_V7_LPBIG_OFFBIG       1
+#else
+#define _POSIX_V7_ILP32_OFF32        1
+#define _POSIX_V7_ILP32_OFFBIG      -1
+#define _POSIX_V7_LP64_OFF64        -1
+#define _POSIX_V7_LPBIG_OFFBIG      -1
+#endif
+
+#define _POSIX2_BC_BASE_MAX         99
+#define _POSIX2_BC_DIM_MAX          2048
+#define _POSIX2_BC_SCALE_MAX        99
+#define _POSIX2_BC_STRING_MAX       1000
+#define _POSIX2_CHARCLASS_NAME_MAX  14
+#define _POSIX2_CHAR_TERM           -1  /* not implemented */
+#define _POSIX2_COLL_WEIGHTS_MAX    2
+#define _POSIX2_C_BIND              _POSIX_VERSION
+#define _POSIX2_C_DEV               -1  /* c dev utilities not implemented */
+#define _POSIX2_EXPR_NEST_MAX       32
+#define _POSIX2_LINE_MAX            2048
+#define _POSIX2_LOCALEDEF           -1  /* localedef utilitiy not implemented */
+#define _POSIX2_RE_DUP_MAX          _POSIX_RE_DUP_MAX
+#define _POSIX2_SW_DEV              -1  /* software dev utilities not implemented */
+#define _POSIX2_UPE                 -1  /* user portability utilities not implemented */
+
+#define _XOPEN_ENH_I18N             -1  /* we don't support internationalization in the C library */
+#define _XOPEN_CRYPT                -1  /* don't support X/Open Encryption */
+#define _XOPEN_IOV_MAX              16
+#define _XOPEN_LEGACY               -1  /* not support all */
+#define _XOPEN_REALTIME             -1 /* we don't support all these functions */
+#define _XOPEN_REALTIME_THREADS     -1  /* same here */
+#define _XOPEN_SHM                  -1
+#define _XOPEN_UNIX                 1
+
 #endif /* _POSIX_LIMITS_H_ */
diff --git a/libc/include/sys/limits.h b/libc/include/sys/limits.h
index edb8c47..be79cf3 100644
--- a/libc/include/sys/limits.h
+++ b/libc/include/sys/limits.h
@@ -115,31 +115,13 @@
 
 /* Bionic-specific definitions */
 
-#define  _POSIX_VERSION             200112L   /* Posix C language bindings version */
+#define  _POSIX_VERSION             200809L   /* Posix C language bindings version */
 #define  _POSIX2_VERSION            -1        /* we don't support Posix command-line tools */
-#define  _POSIX2_C_VERSION          _POSIX_VERSION
-#define  _XOPEN_VERSION             500       /* by Posix definition */
-#define  _XOPEN_XCU_VERSION         -1        /* we don't support command-line utilities */
+#define  _XOPEN_VERSION             700       /* by Posix definition */
 
-/* tell what we implement legacy stuff when appropriate */
-#if _POSIX_VERSION > 0
-#define  _XOPEN_XPG2                1
-#define  _XOPEN_XPG3                1
-#define  _XOPEN_XPG4                1
-#define  _XOPEN_UNIX                1
-#endif
 
-#define  _XOPEN_ENH_I18N          -1  /* we don't support internationalization in the C library */
-#define  _XOPEN_CRYPT             -1  /* don't support X/Open Encryption */
-#define  _XOPEN_LEGACY            -1  /* don't claim we support these, we have some of them but not all */
-#define  _XOPEN_REALTIME          -1 /* we don't support all these functions */
-#define  _XOPEN_REALTIME_THREADS  -1  /* same here */
-
-#define _POSIX_THREAD_DESTRUCTOR_ITERATIONS 4 /* the minimum mandated by POSIX */
-#define PTHREAD_DESTRUCTOR_ITERATIONS _POSIX_THREAD_DESTRUCTOR_ITERATIONS
-#define _POSIX_THREAD_KEYS_MAX 128            /* the minimum mandated by POSIX */
-#define PTHREAD_KEYS_MAX _POSIX_THREAD_KEYS_MAX
-#define _POSIX_THREAD_THREADS_MAX 64          /* the minimum mandated by POSIX */
-#define PTHREAD_THREADS_MAX                   /* bionic has no specific limit */
+#define PTHREAD_DESTRUCTOR_ITERATIONS 4     // >= _POSIX_THREAD_DESTRUCTOR_ITERATIONS
+#define PTHREAD_KEYS_MAX              128   // >= _POSIX_THREAD_KEYS_MAX
+#define PTHREAD_THREADS_MAX           2048  // bionic has no specific limit
 
 #endif
diff --git a/libc/include/sys/sysconf.h b/libc/include/sys/sysconf.h
index 3d058d7..8aa506e 100644
--- a/libc/include/sys/sysconf.h
+++ b/libc/include/sys/sysconf.h
@@ -50,7 +50,7 @@
 #define _SC_PASS_MAX            0x000c
 #define _SC_2_C_BIND            0x000d
 #define _SC_2_C_DEV             0x000e
-#define _SC_2_C_VERSION         0x000f
+#define _SC_2_C_VERSION         0x000f  /* Obsolescent in POSIX.1-2008, TODO: remove it. */
 #define _SC_2_CHAR_TERM         0x0010
 #define _SC_2_FORT_DEV          0x0011
 #define _SC_2_FORT_RUN          0x0012
@@ -68,7 +68,7 @@
 #define _SC_XOPEN_ENH_I18N      0x001e
 #define _SC_XOPEN_SHM           0x001f
 #define _SC_XOPEN_VERSION       0x0020
-#define _SC_XOPEN_XCU_VERSION   0x0021
+#define _SC_XOPEN_XCU_VERSION   0x0021  /* Obsolescent in POSIX.1-2008, TODO: remove it. */
 #define _SC_XOPEN_REALTIME      0x0022
 #define _SC_XOPEN_REALTIME_THREADS  0x0023
 #define _SC_XOPEN_LEGACY        0x0024
@@ -77,10 +77,10 @@
 #define _SC_PAGESIZE            0x0027
 #define _SC_PAGE_SIZE           0x0028
 #define _SC_XOPEN_UNIX          0x0029
-#define _SC_XBS5_ILP32_OFF32    0x002a
-#define _SC_XBS5_ILP32_OFFBIG   0x002b
-#define _SC_XBS5_LP64_OFF64     0x002c
-#define _SC_XBS5_LPBIG_OFFBIG   0x002d
+#define _SC_XBS5_ILP32_OFF32    0x002a  /* Obsolescent in POSIX.1-2008, TODO: remove it. */
+#define _SC_XBS5_ILP32_OFFBIG   0x002b  /* Obsolescent in POSIX.1-2008, TODO: remove it. */
+#define _SC_XBS5_LP64_OFF64     0x002c  /* Obsolescent in POSIX.1-2008, TODO: remove it. */
+#define _SC_XBS5_LPBIG_OFFBIG   0x002d  /* Obsolescent in POSIX.1-2008, TODO: remove it. */
 #define _SC_AIO_LISTIO_MAX      0x002e
 #define _SC_AIO_MAX             0x002f
 #define _SC_AIO_PRIO_DELTA_MAX  0x0030
@@ -129,6 +129,49 @@
 #define _SC_AVPHYS_PAGES                0x0063
 #define _SC_MONOTONIC_CLOCK             0x0064
 
+#define _SC_2_PBS               0x0065
+#define _SC_2_PBS_ACCOUNTING    0x0066
+#define _SC_2_PBS_CHECKPOINT    0x0067
+#define _SC_2_PBS_LOCATE        0x0068
+#define _SC_2_PBS_MESSAGE       0x0069
+#define _SC_2_PBS_TRACK         0x006a
+#define _SC_ADVISORY_INFO       0x006b
+#define _SC_BARRIERS            0x006c
+#define _SC_CLOCK_SELECTION     0x006d
+#define _SC_CPUTIME             0x006e
+#define _SC_HOST_NAME_MAX       0x006f
+#define _SC_IPV6                0x0070
+#define _SC_RAW_SOCKETS         0x0071
+#define _SC_READER_WRITER_LOCKS 0x0072
+#define _SC_REGEXP              0x0073
+#define _SC_SHELL               0x0074
+#define _SC_SPAWN               0x0075
+#define _SC_SPIN_LOCKS          0x0076
+#define _SC_SPORADIC_SERVER     0x0077
+#define _SC_SS_REPL_MAX         0x0078
+#define _SC_SYMLOOP_MAX         0x0079
+#define _SC_THREAD_CPUTIME      0x007a
+#define _SC_THREAD_PROCESS_SHARED       0x007b
+#define _SC_THREAD_ROBUST_PRIO_INHERIT  0x007c
+#define _SC_THREAD_ROBUST_PRIO_PROTECT  0x007d
+#define _SC_THREAD_SPORADIC_SERVER      0x007e
+#define _SC_TIMEOUTS            0x007f
+#define _SC_TRACE               0x0080
+#define _SC_TRACE_EVENT_FILTER  0x0081
+#define _SC_TRACE_EVENT_NAME_MAX  0x0082
+#define _SC_TRACE_INHERIT       0x0083
+#define _SC_TRACE_LOG           0x0084
+#define _SC_TRACE_NAME_MAX      0x0085
+#define _SC_TRACE_SYS_MAX       0x0086
+#define _SC_TRACE_USER_EVENT_MAX  0x0087
+#define _SC_TYPED_MEMORY_OBJECTS  0x0088
+#define _SC_V7_ILP32_OFF32      0x0089
+#define _SC_V7_ILP32_OFFBIG     0x008a
+#define _SC_V7_LP64_OFF64       0x008b
+#define _SC_V7_LPBIG_OFFBIG     0x008c
+#define _SC_XOPEN_STREAMS       0x008d
+#define _SC_XOPEN_UUCP          0x008e
+
 long sysconf(int);
 
 __END_DECLS