date: allow system date to be set

Implement clock_settime(2) and enable the '-s' option to allow
the system time to be set.  This requires elevated privileges.

The code in date.c is now identical to upstream BusyBox.

Costs 256-272 bytes.

3 files changed, 24 insertions, 25 deletions

diff --git a/coreutils/date.c b/coreutils/date.c
index d8e56ef3b..3a89b6caf 100644
--- a/coreutils/date.c
+++ b/coreutils/date.c
@@ -97,9 +97,7 @@
 //usage:#define date_full_usage "\n\n"
 //usage:       "Display time (using +FMT), or set time\n"
 //usage:     "\n        -u              Work in UTC (don't convert to local time)"
-//usage:        IF_NOT_PLATFORM_MINGW32(
 //usage:     "\n        [-s] TIME       Set time to TIME"
-//usage:        )
 //usage:     "\n        -d TIME         Display TIME, not 'now'"
 //usage:        IF_FEATURE_DATE_ISOFMT(
 //usage:     "\n        -D FMT          FMT (strptime format) for -s/-d TIME conversion"
@@ -134,30 +132,19 @@
 
 enum {
         OPT_RFC2822   = (1 << 0), /* R */
-#if !ENABLE_PLATFORM_MINGW32
         OPT_SET       = (1 << 1), /* s */
         OPT_UTC       = (1 << 2), /* u */
         OPT_DATE      = (1 << 3), /* d */
         OPT_REFERENCE = (1 << 4), /* r */
         OPT_ISO8601   = (1 << 5) * ENABLE_FEATURE_DATE_ISOFMT, /* I */
         OPT_STR2DT    = (1 << 6) * ENABLE_FEATURE_DATE_ISOFMT, /* D */
-#else
-        OPT_SET       = (0),      /* s */
-        OPT_UTC       = (1 << 1), /* u */
-        OPT_DATE      = (1 << 2), /* d */
-        OPT_REFERENCE = (1 << 3), /* r */
-        OPT_ISO8601   = (1 << 4) * ENABLE_FEATURE_DATE_ISOFMT, /* I */
-        OPT_STR2DT    = (1 << 5) * ENABLE_FEATURE_DATE_ISOFMT, /* D */
-#endif
 };
 
 #if ENABLE_LONG_OPTS
 static const char date_longopts[] ALIGN1 =
                 "rfc-822\0"   No_argument       "R"
                 "rfc-2822\0"  No_argument       "R"
-#if !ENABLE_PLATFORM_MINGW32
                 "set\0"       Required_argument "s"
-#endif
                 "utc\0"       No_argument       "u"
         /*      "universal\0" No_argument       "u" */
                 "date\0"      Required_argument "d"
@@ -187,25 +174,13 @@ int date_main(int argc UNUSED_PARAM, char **argv)
         char *isofmt_arg = NULL;
 
         opt = getopt32long(argv, "^"
-#if !ENABLE_PLATFORM_MINGW32
                         "Rs:ud:r:"
-#else
-                        "Rud:r:"
-#endif
                         IF_FEATURE_DATE_ISOFMT("I::D:")
-#if !ENABLE_PLATFORM_MINGW32
                         "\0"
                         "d--s:s--d"
                         IF_FEATURE_DATE_ISOFMT(":R--I:I--R"),
-#else
-                        IF_FEATURE_DATE_ISOFMT("\0R--I:I--R"),
-#endif
                         date_longopts,
-#if !ENABLE_PLATFORM_MINGW32
                         &date_str, &date_str, &filename
-#else
-                        &date_str, &filename
-#endif
                         IF_FEATURE_DATE_ISOFMT(, &isofmt_arg, &fmt_str2dt)
         );
         argv += optind;
diff --git a/include/mingw.h b/include/mingw.h
index ae34666e8..232ffadd7 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -294,6 +294,7 @@ time_t timegm(struct tm *tm);
 
 int nanosleep(const struct timespec *req, struct timespec *rem);
 int clock_gettime(clockid_t clockid, struct timespec *tp);
+int clock_settime(clockid_t clockid, const struct timespec *tp);
 
 /*
  * sys/stat.h
diff --git a/win32/mingw.c b/win32/mingw.c
index 86dc75861..5e9c71226 100644
--- a/win32/mingw.c
+++ b/win32/mingw.c
@@ -1008,6 +1008,29 @@ int clock_gettime(clockid_t clockid, struct timespec *tp)
         return 0;
 }
 
+int clock_settime(clockid_t clockid, const struct timespec *tp)
+{
+        SYSTEMTIME st;
+        FILETIME ft;
+
+        if (clockid != CLOCK_REALTIME) {
+                errno = ENOSYS;
+                return -1;
+        }
+
+        timespec_to_filetime(*tp, &ft);
+        if (FileTimeToSystemTime(&ft, &st) == 0) {
+                errno = EINVAL;
+                return -1;
+        }
+
+        if (SetSystemTime(&st) == 0) {
+                errno = EPERM;
+                return -1;
+        }
+        return 0;
+}
+
 int pipe(int filedes[2])
 {
         if (_pipe(filedes, PIPE_BUF, 0) < 0)