diff --git a/src/builtins/time.rs b/src/builtins/time.rs
index badf0bb..aca2efb 100644
--- a/src/builtins/time.rs
+++ b/src/builtins/time.rs
@@ -1,45 +1,217 @@
-//! Contains a [`RuleSet`] for allowing time-related syscalls, but check the comments for why you
-//! probably don't actually need to enable them.
+//! Allow various time related syscalls.
 
-use std::collections::HashSet;
-
-use syscalls::Sysno;
-
-use crate::RuleSet;
+use {super::YesReally, crate::RuleSet, std::collections::BTreeSet, syscalls::Sysno};
 
+/// Allow querying and modifying time as well as sleeping.
+#[derive(Clone, Debug, Default, Eq, Hash, PartialEq, PartialOrd)]
 #[must_use]
-/// Enable syscalls related to time.
 pub struct Time {
-    /// Syscalls that are allowed
-    allowed: HashSet<Sysno>,
+    /// A set of permitted syscalls, added by various constructors and methods.
+    syscalls: BTreeSet<Sysno>,
 }
 
 impl Time {
-    /// Create a new Time [`RuleSet`] with nothing allowed by default.
-    pub fn nothing() -> Time {
-        Time {
-            allowed: HashSet::new(),
-        }
+    /// Construct a new rule, which allows everything:
+    ///   Querying and modifying time as well as sleeping without restriction.
+    pub fn everything() -> YesReally<Self> {
+        Self::nothing().allow_query().allow_sleep().allow_modify()
+    }
+
+    /// Construct a new rule, which allows modifying time without restriction.
+    pub fn modify() -> YesReally<Self> {
+        Self::nothing().allow_modify()
+    }
+
+    /// Construct a new rule, which allows nothing.
+    pub fn nothing() -> Self {
+        Self::default()
+    }
+
+    /// Construct a new rule, which allows querying time without restriction.
+    pub fn query() -> Self {
+        Self::nothing().allow_query()
+    }
+
+    /// Construct a new rule, which allows querying and modifying time without restriction.
+    pub fn query_and_modify() -> YesReally<Self> {
+        Self::nothing().allow_query().allow_modify()
+    }
+
+    /// Construct a new rule, which allows querying time as well as sleeping without restriction.
+    pub fn query_and_sleep() -> Self {
+        Self::nothing().allow_query().allow_sleep()
     }
 
-/// On most 64 bit systems glibc and musl both use the
-/// [`vDSO`](https://man7.org/linux/man-pages/man7/vdso.7.html) to compute the time directly with
-/// rdtsc rather than calling the `clock_gettime` syscall, so in most cases you don't need to
-/// actually enable this.
-    pub fn allow_gettime(mut self) -> Time {
-        self.allowed
-            .extend([Sysno::clock_gettime, Sysno::clock_getres]);
+    /// Construct a new rule, which allows sleeping without restriction.
+    pub fn sleep() -> Self {
+        Self::nothing().allow_sleep()
+    }
+
+    allow! {
+        /// Allow modifying time without restriction.
+        pub unsafe fn allow_modify(self) {
+            /// Allow the `adjtimex` syscall to tune a kernel clock.
+            pub fn allow_adjtimex(adjtimex);
+
+            /// Allow the `clock_adjtime` syscall to tune a kernel clock.
+            pub fn allow_clock_adjtime(clock_adjtime);
+
+            /// Allow the `clock_settime` syscall to set the time of a clock.
+            pub fn allow_clock_settime(clock_settime);
+
+            /// Allow the `settimeofday` syscall to set the time.
+            pub fn allow_settimeofday(settimeofday);
+        }
+
+        /// Allow querying time without restriction.
+        pub fn allow_query(self) {
+            /// Allow the `clock_getres` syscall to get the clock resolution.
+            pub fn allow_clock_getres(clock_getres);
 
-        self
+            /// Allow the `clock_gettime` syscall to get the time of a clock.
+            pub fn allow_clock_gettime(clock_gettime);
+
+            /// Allow the `gettimeofday` syscall to get the time.
+            pub fn allow_gettimeofday(gettimeofday);
+
+            /// Allow the `time` syscall to get the time in seconds.
+            pub fn allow_time(time);
+        }
+
+        /// Allow sleeping without restriction.
+        pub fn allow_sleep(self) {
+            /// Allow the `clock_nanosleep` syscall.
+            pub fn allow_clock_nanosleep(clock_nanosleep);
+
+            /// Allow the `nanosleep` syscall.
+            pub fn allow_nanosleep(nanosleep);
+        }
+    }
+
+    /// On most 64 bit systems glibc and musl both use the
+    /// [`vDSO`](https://man7.org/linux/man-pages/man7/vdso.7.html) to compute the time directly with
+    /// rdtsc rather than calling the `clock_gettime` syscall, so in most cases you don't need to
+    /// actually enable this.
+    pub fn allow_gettime(self) -> Self {
+        self.allow_clock_gettime().allow_clock_getres()
     }
 }
 
 impl RuleSet for Time {
     fn simple_rules(&self) -> Vec<Sysno> {
-        self.allowed.iter().copied().collect()
+        self.syscalls.iter().cloned().collect()
     }
 
     fn name(&self) -> &'static str {
         "Time"
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use {super::Time, crate::RuleSet as _, syscalls::Sysno};
+
+    #[test]
+    fn everything() {
+        let rules = Time::everything().yes_really();
+        assert_eq!(rules.name(), "Time");
+        assert!(rules.conditional_rules().is_empty());
+
+        let simple_rules = rules.simple_rules();
+        assert_eq!(simple_rules.len(), 10);
+        assert!(simple_rules.contains(&Sysno::adjtimex));
+        assert!(simple_rules.contains(&Sysno::clock_adjtime));
+        assert!(simple_rules.contains(&Sysno::clock_getres));
+        assert!(simple_rules.contains(&Sysno::clock_gettime));
+        assert!(simple_rules.contains(&Sysno::clock_nanosleep));
+        assert!(simple_rules.contains(&Sysno::clock_settime));
+        assert!(simple_rules.contains(&Sysno::gettimeofday));
+        assert!(simple_rules.contains(&Sysno::nanosleep));
+        assert!(simple_rules.contains(&Sysno::settimeofday));
+        assert!(simple_rules.contains(&Sysno::time));
+    }
+
+    #[test]
+    fn modify() {
+        let rules = Time::modify().yes_really();
+        assert_eq!(rules.name(), "Time");
+        assert!(rules.conditional_rules().is_empty());
+
+        let simple_rules = rules.simple_rules();
+        assert_eq!(simple_rules.len(), 4);
+        assert!(simple_rules.contains(&Sysno::adjtimex));
+        assert!(simple_rules.contains(&Sysno::clock_adjtime));
+        assert!(simple_rules.contains(&Sysno::clock_settime));
+        assert!(simple_rules.contains(&Sysno::settimeofday));
+    }
+
+    #[test]
+    fn nothing() {
+        let rules = Time::nothing();
+        assert_eq!(rules.name(), "Time");
+        assert!(rules.conditional_rules().is_empty());
+
+        let simple_rules = rules.simple_rules();
+        assert!(simple_rules.is_empty());
+    }
+
+    #[test]
+    fn query() {
+        let rules = Time::query();
+        assert_eq!(rules.name(), "Time");
+        assert!(rules.conditional_rules().is_empty());
+
+        let simple_rules = rules.simple_rules();
+        assert_eq!(simple_rules.len(), 4);
+        assert!(simple_rules.contains(&Sysno::clock_getres));
+        assert!(simple_rules.contains(&Sysno::clock_gettime));
+        assert!(simple_rules.contains(&Sysno::gettimeofday));
+        assert!(simple_rules.contains(&Sysno::time));
+    }
+
+    #[test]
+    fn query_and_modify() {
+        let rules = Time::query_and_modify().yes_really();
+        assert_eq!(rules.name(), "Time");
+        assert!(rules.conditional_rules().is_empty());
+
+        let simple_rules = rules.simple_rules();
+        assert_eq!(simple_rules.len(), 8);
+        assert!(simple_rules.contains(&Sysno::adjtimex));
+        assert!(simple_rules.contains(&Sysno::clock_adjtime));
+        assert!(simple_rules.contains(&Sysno::clock_getres));
+        assert!(simple_rules.contains(&Sysno::clock_gettime));
+        assert!(simple_rules.contains(&Sysno::clock_settime));
+        assert!(simple_rules.contains(&Sysno::gettimeofday));
+        assert!(simple_rules.contains(&Sysno::settimeofday));
+        assert!(simple_rules.contains(&Sysno::time));
+    }
+
+    #[test]
+    fn query_and_sleep() {
+        let rules = Time::query_and_sleep();
+        assert_eq!(rules.name(), "Time");
+        assert!(rules.conditional_rules().is_empty());
+
+        let simple_rules = rules.simple_rules();
+        assert_eq!(simple_rules.len(), 6);
+        assert!(simple_rules.contains(&Sysno::clock_getres));
+        assert!(simple_rules.contains(&Sysno::clock_gettime));
+        assert!(simple_rules.contains(&Sysno::clock_nanosleep));
+        assert!(simple_rules.contains(&Sysno::gettimeofday));
+        assert!(simple_rules.contains(&Sysno::nanosleep));
+        assert!(simple_rules.contains(&Sysno::time));
+    }
+
+    #[test]
+    fn sleep() {
+        let rules = Time::sleep();
+        assert_eq!(rules.name(), "Time");
+        assert!(rules.conditional_rules().is_empty());
+
+        let simple_rules = rules.simple_rules();
+        assert_eq!(simple_rules.len(), 2);
+        assert!(simple_rules.contains(&Sysno::clock_nanosleep));
+        assert!(simple_rules.contains(&Sysno::nanosleep));
+    }
+}