Fix compilation on i686-apple-darwin. (#1000)

On i686-apple-darwin, `time_t` is 32-bit, so it needs `fix_y2038` and
conversions for `Timespec` values.

Fixes #991.

src/backend/libc/fs/syscalls.rs

@@ -802,8 +802,8 @@ pub(crate) fn utimensat(
     flags: AtFlags,
 ) -> io::Result<()> {
     // Old 32-bit version: libc has `utimensat` but it is not y2038 safe by
-    // default. But there may be a `__utimensat16` we can use.
-    #[cfg(fix_y2038)]
+    // default. But there may be a `__utimensat64` we can use.
+    #[cfg(all(fix_y2038, not(apple)))]
     {
         #[cfg(target_env = "gnu")]
         if let Some(libc_utimensat) = __utimensat64.get() {
@@ -874,6 +874,10 @@ pub(crate) fn utimensat(
             ));
         }
 
+        // Convert `times`. We only need this in the child, but do it before
+        // calling `fork` because it might fail.
+        let (attrbuf_size, times, attrs) = times_to_attrlist(times)?;
+
         // `setattrlistat` was introduced in 10.13 along with `utimensat`, so
         // if we don't have `utimensat`, we don't have `setattrlistat` either.
         // Emulate it using `fork`, and `fchdir` and [`setattrlist`].
@@ -896,8 +900,6 @@ pub(crate) fn utimensat(
                     flags_arg |= FSOPT_NOFOLLOW;
                 }
 
-                let (attrbuf_size, times, attrs) = times_to_attrlist(times);
-
                 if setattrlist(
                     c_str(path),
                     &attrs,
@@ -954,7 +956,7 @@ pub(crate) fn utimensat(
     }
 }
 
-#[cfg(fix_y2038)]
+#[cfg(all(fix_y2038, not(apple)))]
 fn utimensat_old(
     dirfd: BorrowedFd<'_>,
     path: &CStr,
@@ -1505,7 +1507,7 @@ fn libc_statvfs_to_statvfs(from: c::statvfs) -> StatVfs {
 pub(crate) fn futimens(fd: BorrowedFd<'_>, times: &Timestamps) -> io::Result<()> {
     // Old 32-bit version: libc has `futimens` but it is not y2038 safe by
     // default. But there may be a `__futimens64` we can use.
-    #[cfg(fix_y2038)]
+    #[cfg(all(fix_y2038, not(apple)))]
     {
         #[cfg(target_env = "gnu")]
         if let Some(libc_futimens) = __futimens64.get() {
@@ -1556,7 +1558,7 @@ pub(crate) fn futimens(fd: BorrowedFd<'_>, times: &Timestamps) -> io::Result<()>
         }
 
         // Otherwise use `fsetattrlist`.
-        let (attrbuf_size, times, attrs) = times_to_attrlist(times);
+        let (attrbuf_size, times, attrs) = times_to_attrlist(times)?;
 
         ret(fsetattrlist(
             borrowed_fd(fd),
@@ -1568,7 +1570,7 @@ pub(crate) fn futimens(fd: BorrowedFd<'_>, times: &Timestamps) -> io::Result<()>
     }
 }
 
-#[cfg(fix_y2038)]
+#[cfg(all(fix_y2038, not(apple)))]
 fn futimens_old(fd: BorrowedFd<'_>, times: &Timestamps) -> io::Result<()> {
     let old_times = [
         c::timespec {
@@ -2125,7 +2127,7 @@ pub(crate) fn fcntl_global_nocache(fd: BorrowedFd<'_>, value: bool) -> io::Resul
 /// Convert `times` from a `futimens`/`utimensat` argument into `setattrlist`
 /// arguments.
 #[cfg(apple)]
-fn times_to_attrlist(times: &Timestamps) -> (c::size_t, [c::timespec; 2], Attrlist) {
+fn times_to_attrlist(times: &Timestamps) -> io::Result<(c::size_t, [c::timespec; 2], Attrlist)> {
     // ABI details.
     const ATTR_CMN_MODTIME: u32 = 0x0000_0400;
     const ATTR_CMN_ACCTIME: u32 = 0x0000_1000;
@@ -2134,7 +2136,8 @@ fn times_to_attrlist(times: &Timestamps) -> (c::size_t, [c::timespec; 2], Attrli
     let mut times = times.clone();
 
     // If we have any `UTIME_NOW` elements, replace them with the current time.
-    if times.last_access.tv_nsec == c::UTIME_NOW || times.last_modification.tv_nsec == c::UTIME_NOW
+    if times.last_access.tv_nsec == c::UTIME_NOW.into()
+        || times.last_modification.tv_nsec == c::UTIME_NOW.into()
     {
         let now = {
             let mut tv = c::timeval {
@@ -2150,11 +2153,17 @@ fn times_to_attrlist(times: &Timestamps) -> (c::size_t, [c::timespec; 2], Attrli
                 tv_nsec: (tv.tv_usec * 1000) as _,
             }
         };
-        if times.last_access.tv_nsec == c::UTIME_NOW {
-            times.last_access = now;
+        if times.last_access.tv_nsec == c::UTIME_NOW.into() {
+            times.last_access = crate::timespec::Timespec {
+                tv_sec: now.tv_sec.into(),
+                tv_nsec: now.tv_nsec as _,
+            };
         }
-        if times.last_modification.tv_nsec == c::UTIME_NOW {
-            times.last_modification = now;
+        if times.last_modification.tv_nsec == c::UTIME_NOW.into() {
+            times.last_modification = crate::timespec::Timespec {
+                tv_sec: now.tv_sec.into(),
+                tv_nsec: now.tv_nsec as _,
+            };
         }
     }
 
@@ -2176,19 +2185,33 @@ fn times_to_attrlist(times: &Timestamps) -> (c::size_t, [c::timespec; 2], Attrli
         tv_nsec: 0,
     }; 2];
     let mut times_index = 0;
-    if times.last_modification.tv_nsec != c::UTIME_OMIT {
+    if times.last_modification.tv_nsec != c::UTIME_OMIT.into() {
         attrs.commonattr |= ATTR_CMN_MODTIME;
-        return_times[times_index] = times.last_modification;
+        return_times[times_index] = c::timespec {
+            tv_sec: times
+                .last_modification
+                .tv_sec
+                .try_into()
+                .map_err(|_| io::Errno::OVERFLOW)?,
+            tv_nsec: times.last_modification.tv_nsec as _,
+        };
         times_index += 1;
         times_size += size_of::<c::timespec>();
     }
-    if times.last_access.tv_nsec != c::UTIME_OMIT {
+    if times.last_access.tv_nsec != c::UTIME_OMIT.into() {
         attrs.commonattr |= ATTR_CMN_ACCTIME;
-        return_times[times_index] = times.last_access;
+        return_times[times_index] = c::timespec {
+            tv_sec: times
+                .last_access
+                .tv_sec
+                .try_into()
+                .map_err(|_| io::Errno::OVERFLOW)?,
+            tv_nsec: times.last_access.tv_nsec as _,
+        };
         times_size += size_of::<c::timespec>();
     }
 
-    (times_size, return_times, attrs)
+    Ok((times_size, return_times, attrs))
 }
 
 /// Support type for `Attrlist`.