diff --git a/libc/calls/_timespec_get.c b/libc/calls/_timespec_get.c
index a7b433347..1bd948775 100644
--- a/libc/calls/_timespec_get.c
+++ b/libc/calls/_timespec_get.c
@@ -26,6 +26,7 @@
  * @param ts receives `CLOCK_REALTIME` timestamp
  * @param base must be `TIME_UTC`
  * @return `base` on success, or `0` on failure
+ * @see _timespec_real()
  */
 int timespec_get(struct timespec *ts, int base) {
   if (base == TIME_UTC && !clock_gettime(CLOCK_REALTIME, ts)) {
diff --git a/libc/calls/_timespec_mono.c b/libc/calls/_timespec_mono.c
index 376966d81..b0e46c612 100644
--- a/libc/calls/_timespec_mono.c
+++ b/libc/calls/_timespec_mono.c
@@ -20,6 +20,13 @@
 #include "libc/calls/struct/timespec.h"
 #include "libc/sysv/consts/clock.h"
 
+/**
+ * Returns current monotonic time.
+ *
+ * This function uses a `CLOCK_MONOTONIC` clock and never fails.
+ *
+ * @see _timespec_real()
+ */
 struct timespec _timespec_mono(void) {
   struct timespec ts;
   _npassert(!clock_gettime(CLOCK_MONOTONIC_FAST, &ts));
diff --git a/libc/calls/_timespec_real.c b/libc/calls/_timespec_real.c
index 2e49004c6..f54a11a70 100644
--- a/libc/calls/_timespec_real.c
+++ b/libc/calls/_timespec_real.c
@@ -20,6 +20,15 @@
 #include "libc/calls/struct/timespec.h"
 #include "libc/sysv/consts/clock.h"
 
+/**
+ * Returns current time.
+ *
+ * This function uses a `CLOCK_REALTIME` clock and never fails. Unlike
+ * clock_gettime() or timespec_real() this interface avoids the use of
+ * pointers which lets time handling code become more elegant.
+ *
+ * @see _timespec_mono()
+ */
 struct timespec _timespec_real(void) {
   struct timespec ts;
   _npassert(!clock_gettime(CLOCK_REALTIME_FAST, &ts));
diff --git a/libc/calls/_timespec_tomicros.c b/libc/calls/_timespec_tomicros.c
index 72d591858..2155be4c0 100644
--- a/libc/calls/_timespec_tomicros.c
+++ b/libc/calls/_timespec_tomicros.c
@@ -21,6 +21,17 @@
 
 /**
  * Reduces `ts` from 1e-9 to 1e-6 granularity w/ ceil rounding.
+ *
+ * This function uses ceiling rounding. For example, if `ts` is one
+ * nanosecond, then one microsecond will be returned. Ceil rounding
+ * is needed by many interfaces, e.g. setitimer(), because the zero
+ * timestamp has a special meaning.
+ *
+ * This function also detects overflow in which case `INT64_MAX` or
+ * `INT64_MIN` may be returned. The `errno` variable isn't changed.
+ *
+ * @return 64-bit scalar holding microseconds since epoch
+ * @see _timespec_totimeval()
  */
 int64_t _timespec_tomicros(struct timespec ts) {
   int64_t us;
diff --git a/libc/calls/_timespec_tomillis.c b/libc/calls/_timespec_tomillis.c
index 31a2ecda8..7fb07dc35 100644
--- a/libc/calls/_timespec_tomillis.c
+++ b/libc/calls/_timespec_tomillis.c
@@ -21,6 +21,16 @@
 
 /**
  * Reduces `ts` from 1e-9 to 1e-3 granularity w/ ceil rounding.
+ *
+ * This function uses ceiling rounding. For example, if `ts` is one
+ * nanosecond, then one millisecond will be returned. Ceil rounding
+ * is needed by many interfaces, e.g. setitimer(), because the zero
+ * timestamp has a special meaning.
+ *
+ * This function also detects overflow in which case `INT64_MAX` or
+ * `INT64_MIN` may be returned. The `errno` variable isn't changed.
+ *
+ * @return 64-bit scalar milliseconds since epoch
  */
 int64_t _timespec_tomillis(struct timespec ts) {
   int64_t ms;
diff --git a/libc/calls/_timespec_tonanos.c b/libc/calls/_timespec_tonanos.c
index 369b66ed0..6edac6ac1 100644
--- a/libc/calls/_timespec_tonanos.c
+++ b/libc/calls/_timespec_tonanos.c
@@ -20,7 +20,12 @@
 #include "libc/limits.h"
 
 /**
- * Converts timespec interval to nanoseconds.
+ * Converts timespec to scalar.
+ *
+ * This function will detect overflow in which case `INT64_MAX` or
+ * `INT64_MIN` may be returned. The `errno` variable isn't changed.
+ *
+ * @return 64-bit integer holding nanoseconds since epoch
  */
 int64_t _timespec_tonanos(struct timespec x) {
   int64_t ns;
diff --git a/libc/calls/_timespec_totimeval.c b/libc/calls/_timespec_totimeval.c
index 32bb83e31..5786513a5 100644
--- a/libc/calls/_timespec_totimeval.c
+++ b/libc/calls/_timespec_totimeval.c
@@ -20,6 +20,14 @@
 
 /**
  * Reduces `ts` from 1e-9 to 1e-6 granularity w/ ceil rounding.
+ *
+ * This function uses ceiling rounding. For example, if `ts` is one
+ * nanosecond, then one microsecond will be returned. Ceil rounding
+ * is needed by many interfaces, e.g. setitimer(), because the zero
+ * timestamp has a special meaning.
+ *
+ * @return microseconds since epoch
+ * @see _timespec_tomicros()
  */
 struct timeval _timespec_totimeval(struct timespec ts) {
   if (ts.tv_nsec < 1000000000 - 999) {
diff --git a/libc/calls/_timeval_totimespec.c b/libc/calls/_timeval_totimespec.c
index 65a992bb4..e508155fd 100644
--- a/libc/calls/_timeval_totimespec.c
+++ b/libc/calls/_timeval_totimespec.c
@@ -18,6 +18,9 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/struct/timeval.h"
 
+/**
+ * Coerces `tv` from 1e-6 to 1e-9 granularity.
+ */
 struct timespec _timeval_totimespec(struct timeval tv) {
   return (struct timespec){tv.tv_sec, tv.tv_usec * 1000};
 }
diff --git a/libc/calls/clock_nanosleep.c b/libc/calls/clock_nanosleep.c
index 6eb147f00..3a587725c 100644
--- a/libc/calls/clock_nanosleep.c
+++ b/libc/calls/clock_nanosleep.c
@@ -65,14 +65,10 @@
  *     of your preferred platforms to see what other clocks might work
  * @param flags can be 0 for relative and `TIMER_ABSTIME` for absolute
  * @param req can be a relative or absolute time, depending on `flags`
- * @param rem will be updated with the unslept time only when `flags`
- *     is zero, otherwise `rem` is ignored; when this call completes,
- *     that means `rem` will be set to `{0, 0}`, and shall only have
- *     something else when -1 is returned with `EINTR`, which means
- *     there was a signal delivery that happened mid-sleep and `rem`
- *     reflects (poorly) how much remaining time was left over, in
- *     case the caller wishes to retry the sleep operation, noting
- *     this isn't recommended since relative timestamps can drift
+ * @param rem shall be updated with the remainder of unslept time when
+ *     (1) it's non-null; (2) `flags` is 0; and (3) -1 w/ `EINTR` is
+ *     returned; if this function returns 0 then `rem` is undefined;
+ *     if flags is `TIMER_ABSTIME` then `rem` is ignored
  * @return 0 on success, or -1 w/ errno
  * @raise EINTR when a signal got delivered while we were waiting
  * @raise ENOTSUP if `clock` is known but we can't use it here
@@ -107,14 +103,6 @@ int clock_nanosleep(int clock, int flags, const struct timespec *req,
     rc = sys_clock_nanosleep_nt(clock, flags, req, rem);
   }
 
-  // Linux Kernel doesn't change the remainder value on success, but
-  // some kernels like OpenBSD will. POSIX doesn't specify the Linux
-  // behavior. So we polyfill it here.
-  if (!rc && !flags && rem) {
-    rem->tv_sec = 0;
-    rem->tv_nsec = 0;
-  }
-
   STRACE("clock_nanosleep(%s, %s, %s, [%s]) → %d% m", DescribeClockName(clock),
          DescribeSleepFlags(flags), flags, DescribeTimespec(0, req),
          DescribeTimespec(rc, rem), rc);
diff --git a/libc/calls/futimens.c b/libc/calls/futimens.c
index 952f8a9b5..d53957468 100644
--- a/libc/calls/futimens.c
+++ b/libc/calls/futimens.c
@@ -26,8 +26,8 @@
  * Changes access/modified time on open file, the modern way.
  *
  * XNU only has microsecond (1e-6) accuracy. Windows only has
- * hectonanosecond (1e-7) accuracy. RHEL5 is somewhat broken so utimes()
- * is recommended if portability to old versions of Linux is desired.
+ * hectonanosecond (1e-7) accuracy. RHEL5 (Linux c. 2007) doesn't
+ * support this system call.
  *
  * @param fd is file descriptor of file whose timestamps will change
  * @param ts is {access, modified} timestamps, or null for current time
diff --git a/libc/calls/futimes.c b/libc/calls/futimes.c
index 6e2fd03db..83547baee 100644
--- a/libc/calls/futimes.c
+++ b/libc/calls/futimes.c
@@ -16,26 +16,45 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/asan.internal.h"
+#include "libc/calls/struct/itimerval.internal.h"
 #include "libc/calls/struct/timespec.h"
+#include "libc/calls/struct/timespec.internal.h"
 #include "libc/calls/struct/timeval.h"
+#include "libc/dce.h"
+#include "libc/intrin/strace.internal.h"
+#include "libc/sysv/errfuns.h"
 
 /**
  * Sets atime/mtime on file descriptor.
  *
  * @param ts is atime/mtime, or null for current time
- * @note better than microsecond precision on most platforms
- * @see fstat() for reading timestamps
+ * @return 0 on success, or -1 w/ errno
+ * @raise ENOTSUP if `fd` is on zip filesystem
+ * @raise EBADF if `fd` isn't an open file descriptor
+ * @raise EPERM if pledge() is in play without `fattr` promise
+ * @raise EINVAL if `tv` specifies a microsecond value that's out of range
+ * @raise ENOSYS on RHEL5 or bare metal
+ * @see futimens() for modern version
+ * @asyncsignalsafe
+ * @threadsafe
  */
 int futimes(int fd, const struct timeval tv[2]) {
-  // TODO(jart): does this work on rhel5? what's up with this?
+  int rc;
   struct timespec ts[2];
+
   if (tv) {
     ts[0].tv_sec = tv[0].tv_sec;
     ts[0].tv_nsec = tv[0].tv_usec * 1000;
     ts[1].tv_sec = tv[1].tv_sec;
     ts[1].tv_nsec = tv[1].tv_usec * 1000;
-    return utimensat(fd, NULL, ts, 0);
+    rc = __utimens(fd, 0, ts, 0);
   } else {
-    return utimensat(fd, NULL, NULL, 0);
+    rc = __utimens(fd, 0, 0, 0);
   }
+
+  STRACE("futimes(%d, {%s, %s}) → %d% m", fd, DescribeTimeval(0, tv),
+         DescribeTimeval(0, tv ? tv + 1 : 0), rc);
+
+  return rc;
 }
diff --git a/libc/calls/nanosleep.c b/libc/calls/nanosleep.c
index b39620b82..12184ada2 100644
--- a/libc/calls/nanosleep.c
+++ b/libc/calls/nanosleep.c
@@ -30,13 +30,11 @@
  * Sleeps for relative amount of time.
  *
  * @param req is the duration of time we should sleep
- * @param rem if non-NULL will receive the amount of time that wasn't
- *     slept because a signal was delivered. If no signal's delivered
- *     then this value will be set to `{0, 0}`. It's also fine to set
- *     this value to the same pointer as `req`
+ * @param rem if non-null will be updated with the remainder of unslept
+ *     time when -1 w/ `EINTR` is returned otherwise `rem` is undefined
  * @return 0 on success, or -1 w/ errno
  * @raise EINVAL if `req->tv_nsec ∉ [0,1000000000)`
- * @raise EINTR if a signal was delivered, and `rem` is updated
+ * @raise EINTR if a signal was delivered and `rem` is updated
  * @raise EFAULT if `req` is NULL or `req` / `rem` is a bad pointer
  * @raise ENOSYS on bare metal
  * @see clock_nanosleep()
@@ -58,19 +56,11 @@ int nanosleep(const struct timespec *req, struct timespec *rem) {
   } else if (IsXnu()) {
     rc = sys_nanosleep_xnu(req, rem);
   } else if (IsMetal()) {
-    rc = enosys(); /* TODO: Sleep on Metal */
+    rc = enosys();
   } else {
     rc = sys_nanosleep_nt(req, rem);
   }
 
-  // Linux Kernel doesn't change the remainder value on success, but
-  // some kernels like OpenBSD will. POSIX doesn't specify the Linux
-  // behavior. So we polyfill it here.
-  if (!rc && rem) {
-    rem->tv_sec = 0;
-    rem->tv_nsec = 0;
-  }
-
 #ifdef SYSDEBUG
   if (!__time_critical) {
     STRACE("nanosleep(%s, [%s]) → %d% m", DescribeTimespec(rc, req),
diff --git a/libc/calls/setitimer.c b/libc/calls/setitimer.c
index d7538c2f0..725ad24c8 100644
--- a/libc/calls/setitimer.c
+++ b/libc/calls/setitimer.c
@@ -16,11 +16,11 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/intrin/strace.internal.h"
 #include "libc/calls/struct/itimerval.h"
 #include "libc/calls/struct/itimerval.internal.h"
 #include "libc/dce.h"
 #include "libc/intrin/asan.internal.h"
+#include "libc/intrin/strace.internal.h"
 #include "libc/sysv/errfuns.h"
 #include "libc/time/time.h"
 
@@ -29,28 +29,28 @@
  *
  * Raise SIGALRM every 1.5s:
  *
- *     CHECK_NE(-1, sigaction(SIGALRM,
- *                            &(struct sigaction){.sa_sigaction = _missingno},
- *                            NULL));
- *     CHECK_NE(-1, setitimer(ITIMER_REAL,
- *                            &(const struct itimerval){{1, 500000},
- *                                                      {1, 500000}},
- *                            NULL));
+ *     sigaction(SIGALRM,
+ *               &(struct sigaction){.sa_sigaction = _missingno},
+ *               NULL);
+ *     setitimer(ITIMER_REAL,
+ *               &(const struct itimerval){{1, 500000},
+ *                                         {1, 500000}},
+ *               NULL);
  *
  * Set single-shot 50ms timer callback to interrupt laggy connect():
  *
- *     CHECK_NE(-1, sigaction(SIGALRM,
- *                            &(struct sigaction){.sa_sigaction = _missingno,
- *                                                .sa_flags = SA_RESETHAND},
- *                            NULL));
- *     CHECK_NE(-1, setitimer(ITIMER_REAL,
- *                            &(const struct itimerval){{0, 0}, {0, 50000}},
- *                            NULL));
+ *     sigaction(SIGALRM,
+ *               &(struct sigaction){.sa_sigaction = _missingno,
+ *                                   .sa_flags = SA_RESETHAND},
+ *               NULL);
+ *     setitimer(ITIMER_REAL,
+ *               &(const struct itimerval){{0, 0}, {0, 50000}},
+ *               NULL);
  *     if (connect(...) == -1 && errno == EINTR) { ... }
  *
  * Disarm timer:
  *
- *     CHECK_NE(-1, setitimer(ITIMER_REAL, &(const struct itimerval){0}, NULL));
+ *     setitimer(ITIMER_REAL, &(const struct itimerval){0}, NULL);
  *
  * Be sure to check for EINTR on your i/o calls, for best low latency.
  *
@@ -81,6 +81,7 @@ int setitimer(int which, const struct itimerval *newvalue,
     rc = sys_setitimer_nt(which, newvalue, oldvalue);
   }
 
+#ifdef SYSDEBUG
   if (newvalue && oldvalue) {
     STRACE("setitimer(%d, "
            "{{%'ld, %'ld}, {%'ld, %'ld}}, "
@@ -100,6 +101,7 @@ int setitimer(int which, const struct itimerval *newvalue,
   } else {
     STRACE("setitimer(%d, NULL, NULL) → %d% m", which, rc);
   }
+#endif
 
   return rc;
 }
diff --git a/libc/calls/sys_utimes_nt.c b/libc/calls/sys_utimes_nt.c
deleted file mode 100644
index 9d1fd71c6..000000000
--- a/libc/calls/sys_utimes_nt.c
+++ /dev/null
@@ -1,36 +0,0 @@
-/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
-│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2021 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/calls/struct/timespec.h"
-#include "libc/calls/struct/timespec.internal.h"
-#include "libc/calls/struct/timeval.h"
-#include "libc/calls/struct/timeval.internal.h"
-#include "libc/sysv/consts/at.h"
-
-textwindows int sys_utimes_nt(const char *path, const struct timeval tv[2]) {
-  struct timespec ts[2];
-  if (tv) {
-    ts[0].tv_sec = tv[0].tv_sec;
-    ts[0].tv_nsec = tv[0].tv_usec * 1000;
-    ts[1].tv_sec = tv[1].tv_sec;
-    ts[1].tv_nsec = tv[1].tv_usec * 1000;
-    return sys_utimensat_nt(AT_FDCWD, path, ts, 0);
-  } else {
-    return sys_utimensat_nt(AT_FDCWD, path, NULL, 0);
-  }
-}
diff --git a/libc/calls/utime.c b/libc/calls/utime.c
index ac8c97d69..363f6eff7 100644
--- a/libc/calls/utime.c
+++ b/libc/calls/utime.c
@@ -17,16 +17,16 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/struct/timeval.h"
-#include "libc/str/str.h"
-#include "libc/sysv/consts/at.h"
 #include "libc/time/struct/utimbuf.h"
 
 /**
  * Changes last accessed/modified times on file.
  *
  * @param times if NULL means now
- * @return 0 on success or -1 w/ errno
+ * @return 0 on success, or -1 w/ errno
+ * @see utimensat() for modern version
  * @asyncsignalsafe
+ * @threadsafe
  */
 int utime(const char *path, const struct utimbuf *times) {
   struct timeval tv[2];
diff --git a/libc/calls/utimens.c b/libc/calls/utimens.c
index 5be86ea96..a4830ce37 100644
--- a/libc/calls/utimens.c
+++ b/libc/calls/utimens.c
@@ -21,6 +21,8 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/internal.h"
 #include "libc/calls/struct/timespec.internal.h"
+#include "libc/calls/struct/timeval.internal.h"
+#include "libc/calls/syscall_support-sysv.internal.h"
 #include "libc/dce.h"
 #include "libc/intrin/asan.internal.h"
 #include "libc/intrin/describeflags.internal.h"
@@ -46,6 +48,8 @@ int __utimens(int fd, const char *path, const struct timespec ts[2],
              (path && (_weaken(__zipos_parseuri) &&
                        _weaken(__zipos_parseuri)(path, &zipname) != -1))) {
     rc = enotsup();
+  } else if (IsLinux() && !__is_linux_2_6_23() && fd == AT_FDCWD && !flags) {
+    rc = sys_utimes(path, (void *)ts);  // rhel5 truncates to seconds
   } else if (!IsWindows()) {
     rc = sys_utimensat(fd, path, ts, flags);
   } else {
diff --git a/libc/calls/utimensat.c b/libc/calls/utimensat.c
index 893cbe8a7..06f39f06f 100644
--- a/libc/calls/utimensat.c
+++ b/libc/calls/utimensat.c
@@ -34,10 +34,13 @@
  *
  * XNU only has microsecond (1e-6) accuracy and there's no
  * `dirfd`-relative support. Windows only has hectonanosecond (1e-7)
- * accuracy. RHEL5 is somewhat broken so utimes() is recommended if
- * portability to old versions of Linux is desired.
+ * accuracy. RHEL5 doesn't support `dirfd` or `flags` and will truncate
+ * timestamps to seconds.
  *
- * @param dirfd is usually `AT_FDCWD`
+ * If you'd rather specify an open file descriptor rather than its
+ * filesystem path, then consider using futimens().
+ *
+ * @param dirfd can be `AT_FDCWD` or an open directory
  * @param path is filename whose timestamps should be modified
  * @param ts is {access, modified} timestamps, or null for current time
  * @param flags can have `AT_SYMLINK_NOFOLLOW` when `path` is specified
@@ -52,21 +55,23 @@
  * @raise EBADF if `dirfd` isn't a valid fd or `AT_FDCWD`
  * @raise EFAULT if `path` or `ts` memory was invalid
  * @raise EROFS if `path` is on read-only filesystem
- * @raise ENOSYS on bare metal
- * @see futimens()
+ * @raise ENOSYS on bare metal or on rhel5 when `dirfd` or `flags` is used
  * @asyncsignalsafe
  * @threadsafe
  */
 int utimensat(int dirfd, const char *path, const struct timespec ts[2],
               int flags) {
   int rc;
+
   if (!path) {
     rc = efault();  // linux kernel abi behavior isn't supported
   } else {
     rc = __utimens(dirfd, path, ts, flags);
   }
+
   STRACE("utimensat(%s, %#s, {%s, %s}, %#o) → %d% m", DescribeDirfd(dirfd),
          path, DescribeTimespec(0, ts), DescribeTimespec(0, ts ? ts + 1 : 0),
          flags, rc);
+
   return rc;
 }
diff --git a/libc/calls/utimes.c b/libc/calls/utimes.c
index 7d804e9ef..6ab0bdb7b 100644
--- a/libc/calls/utimes.c
+++ b/libc/calls/utimes.c
@@ -16,57 +16,34 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/calls/asan.internal.h"
 #include "libc/calls/struct/itimerval.internal.h"
+#include "libc/calls/struct/timespec.h"
+#include "libc/calls/struct/timespec.internal.h"
 #include "libc/calls/struct/timeval.h"
-#include "libc/calls/struct/timeval.internal.h"
-#include "libc/dce.h"
-#include "libc/intrin/asan.internal.h"
 #include "libc/intrin/strace.internal.h"
-#include "libc/intrin/weaken.h"
 #include "libc/sysv/consts/at.h"
-#include "libc/sysv/errfuns.h"
-#include "libc/zipos/zipos.internal.h"
 
 /**
  * Changes last accessed/modified timestamps on file.
  *
  * @param tv is access/modified timestamps, or NULL which means now
  * @return 0 on success, or -1 w/ errno
- * @raise ENOTSUP if `path` is a zip filesystem path
- * @raise EROFS if `path` is on a read-only filesystem
- * @raise EFAULT if `path` or `tv` points to invalid memory
- * @raise EPERM if pledge() is in play without fattr promise
- * @raise ENOENT if `path` doesn't exist or is an empty string
- * @raise EACCES if unveil() is in play and `path` isn't unveiled
- * @raise ELOOP if a loop was detected resolving components of `path`
- * @raise ENAMETOOLONG if symlink-resolved `path` length exceeds `PATH_MAX`
- * @raise ENAMETOOLONG if component in `path` exists longer than `NAME_MAX`
- * @raise EINVAL if `tv` specifies a microseconds value that's out of range
- * @raise EACCES if we don't have permission to search a component of `path`
- * @raise ENOTDIR if a directory component in `path` exists as non-directory
- * @raise ENOSYS on bare metal
+ * @note truncates to second precision on rhel5
+ * @see utimensat() for modern version
  * @asyncsignalsafe
- * @see stat()
+ * @threadsafe
  */
 int utimes(const char *path, const struct timeval tv[2]) {
   int rc;
-  struct ZiposUri zipname;
-  if (IsMetal()) {
-    rc = enosys();
-  } else if (IsAsan() && tv &&
-             (!__asan_is_valid_timeval(tv + 0) ||
-              !__asan_is_valid_timeval(tv + 1))) {
-    rc = efault();
-  } else if (_weaken(__zipos_parseuri) &&
-             _weaken(__zipos_parseuri)(path, &zipname) != -1) {
-    rc = enotsup();
-  } else if (!IsWindows()) {
-    // we don't modernize utimes() into utimensat() because the
-    // latter is poorly supported and utimes() works everywhere
-    rc = sys_utimes(path, tv);
+  struct timespec ts[2];
+  if (tv) {
+    ts[0].tv_sec = tv[0].tv_sec;
+    ts[0].tv_nsec = tv[0].tv_usec * 1000;
+    ts[1].tv_sec = tv[1].tv_sec;
+    ts[1].tv_nsec = tv[1].tv_usec * 1000;
+    rc = __utimens(AT_FDCWD, path, ts, 0);
   } else {
-    rc = sys_utimes_nt(path, tv);
+    rc = __utimens(AT_FDCWD, path, 0, 0);
   }
   STRACE("utimes(%#s, {%s, %s}) → %d% m", path, DescribeTimeval(0, tv),
          DescribeTimeval(0, tv ? tv + 1 : 0), rc);
diff --git a/libc/intrin/bzero.c b/libc/intrin/bzero.c
index 40becb89b..c65c9cd42 100644
--- a/libc/intrin/bzero.c
+++ b/libc/intrin/bzero.c
@@ -130,7 +130,7 @@ microarchitecture("avx") static void bzero_avx(char *p, size_t n) {
  * @return p
  * @asyncsignalsafe
  */
-void(bzero)(void *p, size_t n) {
+void bzero(void *p, size_t n) {
   char *b;
   uint64_t x;
   b = p;
diff --git a/test/libc/calls/_timespec_test.c b/test/libc/calls/_timespec_test.c
index bd2d586d9..e51b3b4f5 100644
--- a/test/libc/calls/_timespec_test.c
+++ b/test/libc/calls/_timespec_test.c
@@ -64,12 +64,19 @@ TEST(_timespec_frommicros, test) {
 }
 
 TEST(_timespec_tomillis, test) {
+  EXPECT_EQ(0, _timespec_tomillis((struct timespec){0, 0}));
+  EXPECT_EQ(1, _timespec_tomillis((struct timespec){0, 1}));
+  EXPECT_EQ(1, _timespec_tomillis((struct timespec){0, 999999}));
+  EXPECT_EQ(1, _timespec_tomillis((struct timespec){0, 1000000}));
+  EXPECT_EQ(1000, _timespec_tomillis((struct timespec){0, 999999999}));
   EXPECT_EQ(2123, _timespec_tomillis((struct timespec){2, 123000000}));
   EXPECT_EQ(INT64_MAX, _timespec_tomillis((struct timespec){INT64_MAX, 0}));
   EXPECT_EQ(INT64_MIN, _timespec_tomillis((struct timespec){INT64_MIN, 0}));
 }
 
 TEST(_timespec_tomicros, test) {
+  EXPECT_EQ(0, _timespec_tomicros((struct timespec){0, 0}));
+  EXPECT_EQ(1, _timespec_tomicros((struct timespec){0, 1}));
   EXPECT_EQ(2000123, _timespec_tomicros((struct timespec){2, 123000}));
   EXPECT_EQ(INT64_MAX, _timespec_tomicros((struct timespec){INT64_MAX, 0}));
   EXPECT_EQ(INT64_MIN, _timespec_tomicros((struct timespec){INT64_MIN, 0}));
diff --git a/test/libc/calls/nanosleep_test.c b/test/libc/calls/nanosleep_test.c
index 369a259f3..a57197ebc 100644
--- a/test/libc/calls/nanosleep_test.c
+++ b/test/libc/calls/nanosleep_test.c
@@ -22,6 +22,7 @@
 #include "libc/calls/struct/timespec.h"
 #include "libc/errno.h"
 #include "libc/intrin/describeflags.internal.h"
+#include "libc/sysv/consts/clock.h"
 #include "libc/sysv/consts/itimer.h"
 #include "libc/sysv/consts/sa.h"
 #include "libc/sysv/consts/sig.h"
@@ -41,11 +42,16 @@ TEST(nanosleep, testInvalid) {
   EXPECT_SYS(EINVAL, -1, nanosleep(&ts, 0));
 }
 
-TEST(nanosleep, testNoSignalIsDelivered_remIsSetToZero) {
+TEST(nanosleep, testNoSignalIsDelivered) {
   struct timespec ts = {0, 1};
   ASSERT_SYS(0, 0, nanosleep(&ts, &ts));
-  EXPECT_EQ(0, ts.tv_sec);
-  EXPECT_EQ(0, ts.tv_nsec);
+  ASSERT_SYS(0, 0, nanosleep(&ts, 0));
+}
+
+TEST(clock_nanosleep, testNoSignalIsDelivered) {
+  struct timespec ts = {0, 1};
+  ASSERT_SYS(0, 0, clock_nanosleep(CLOCK_REALTIME, 0, &ts, &ts));
+  ASSERT_SYS(0, 0, clock_nanosleep(CLOCK_REALTIME, 0, &ts, 0));
 }
 
 TEST(nanosleep, testInterrupt_remIsUpdated) {
diff --git a/test/libc/calls/utimensat_test.c b/test/libc/calls/utimensat_test.c
index ff46276fb..59f3f0e35 100644
--- a/test/libc/calls/utimensat_test.c
+++ b/test/libc/calls/utimensat_test.c
@@ -19,8 +19,10 @@
 #include "libc/calls/calls.h"
 #include "libc/calls/struct/stat.h"
 #include "libc/calls/struct/timespec.h"
+#include "libc/calls/struct/timeval.h"
 #include "libc/calls/syscall_support-sysv.internal.h"
 #include "libc/dce.h"
+#include "libc/errno.h"
 #include "libc/sysv/consts/at.h"
 #include "libc/sysv/consts/o.h"
 #include "libc/sysv/consts/utime.h"
@@ -33,6 +35,50 @@ void SetUpOnce(void) {
   ASSERT_SYS(0, 0, pledge("stdio rpath wpath cpath fattr", 0));
 }
 
+TEST(utimes, test) {
+  struct stat st;
+  struct timeval tv[2] = {
+      {1655455857, 1},  // atim: Fri Jun 17 2022 08:50:57 GMT+0000
+      {827727928, 2},   // mtim: Mon Mar 25 1996 04:25:28 GMT+0000
+  };
+  EXPECT_SYS(0, 0, touch("boop", 0644));
+  EXPECT_SYS(0, 0, utimes("boop", tv));
+  EXPECT_SYS(0, 0, stat("boop", &st));
+  EXPECT_EQ(1655455857, st.st_atim.tv_sec);
+  EXPECT_EQ(827727928, st.st_mtim.tv_sec);
+  if (IsLinux() && !__is_linux_2_6_23()) {
+    // rhel5 only seems to have second granularity
+    EXPECT_EQ(0, st.st_atim.tv_nsec);
+    EXPECT_EQ(0, st.st_mtim.tv_nsec);
+  } else {
+    EXPECT_EQ(1000, st.st_atim.tv_nsec);
+    EXPECT_EQ(2000, st.st_mtim.tv_nsec);
+  }
+}
+
+TEST(futimes, test) {
+  if (IsLinux() && !__is_linux_2_6_23()) return;
+  struct stat st;
+  struct timeval tv[2] = {{1655455857, 1}, {827727928, 2}};
+  EXPECT_SYS(0, 3, creat("boop", 0644));
+  EXPECT_SYS(0, 0, futimes(3, tv));
+  EXPECT_SYS(0, 0, fstat(3, &st));
+  EXPECT_EQ(1655455857, st.st_atim.tv_sec);
+  EXPECT_EQ(827727928, st.st_mtim.tv_sec);
+  EXPECT_EQ(1000, st.st_atim.tv_nsec);
+  EXPECT_EQ(2000, st.st_mtim.tv_nsec);
+  EXPECT_SYS(0, 0, close(3));
+}
+
+TEST(futimes, rhel5_enosys) {
+  if (IsLinux() && !__is_linux_2_6_23()) {
+    struct timeval tv[2] = {{1655455857}, {827727928}};
+    EXPECT_SYS(0, 3, creat("boop", 0644));
+    EXPECT_SYS(ENOSYS, -1, futimes(3, tv));
+    EXPECT_SYS(0, 0, close(3));
+  }
+}
+
 TEST(utimensat, test) {
   struct stat st;
   struct timespec ts[2] = {