Merge branch 'ctime_r' into 'master'

Add test for ctime_r(), replace mem::uninitialized()

See merge request redox-os/relibc!273

src/header/time/mod.rs

@@ -141,9 +141,22 @@ pub unsafe extern "C" fn ctime(clock: *const time_t) -> *mut c_char {
 
 #[no_mangle]
 pub unsafe extern "C" fn ctime_r(clock: *const time_t, buf: *mut c_char) -> *mut c_char {
-    let mut tm1: tm = core::mem::uninitialized();
+    // Using MaybeUninit<tm> seems to cause a panic during the build process
+    let mut tm1 = tm {
+        tm_sec: 0,
+        tm_min: 0,
+        tm_hour: 0,
+        tm_mday: 0,
+        tm_mon: 0,
+        tm_year: 0,
+        tm_wday: 0,
+        tm_yday: 0,
+        tm_isdst: 0,
+        tm_gmtoff: 0,
+        tm_zone: core::ptr::null_mut(),
+    };
     localtime_r(clock, &mut tm1);
-    asctime_r(&mut tm1, buf)
+    asctime_r(&tm1, buf)
 }
 
 #[no_mangle]

tests/expected/time/localtime.stdout

@@ -6,3 +6,4 @@ Year 70, Day of year: 0, Month 0, Day of month: 1, Day of week: 4, 0:0:0
 Year 70, Day of year: 0, Month 0, Day of month: 1, Day of week: 4, 0:0:1
 Year 118, Day of year: 193, Month 6, Day of month: 13, Day of week: 5, 4:9:10
 Fri Jul 13 06:03:43 2018
+Fri Jul 13 06:03:43 2018

tests/time/localtime.c

@@ -17,4 +17,15 @@ int main(void) {
 
     time_t input = 1531461823;
     fputs(ctime(&input), stdout); // Omit newline
+
+    char ctime_r_buffer[26];
+    /* ctime_r() generally returns the address of the provided buffer,
+     * but may return NULL upon error according to the spec. */
+    char *ctime_r_result = ctime_r(&input, ctime_r_buffer);
+    if (ctime_r_result == ctime_r_buffer) {
+        fputs(ctime_r_result, stdout);
+    }
+    else {
+        printf("Unexpected pointer from ctime_r: %p\n", ctime_r_result);
+    }
 }