bc: convert to "G trick" - this returns bc to zero bss increase

[oweals/busybox.git] / util-linux / rdate.c

diff --git a/util-linux/rdate.c b/util-linux/rdate.c
index 2c3de74bc8fc71c542a01b85d0ed0577cab2427c..5ec795208050f4c251a546c65a468e2a3a1a1b8c 100644 (file)
--- a/util-linux/rdate.c
+++ b/util-linux/rdate.c
@@ -1,12 +1,31 @@
 /* vi: set sw=4 ts=4: */
 /*
  * The Rdate command will ask a time server for the RFC 868 time
- *  and optionally set the system time.
+ * and optionally set the system time.
  *
  * by Sterling Huxley <sterling@europa.com>
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
-*/
+ */
+//config:config RDATE
+//config:      bool "rdate (6 kb)"
+//config:      default y
+//config:      help
+//config:      The rdate utility allows you to synchronize the date and time of your
+//config:      system clock with the date and time of a remote networked system using
+//config:      the RFC868 protocol, which is built into the inetd daemon on most
+//config:      systems.
+
+//applet:IF_RDATE(APPLET(rdate, BB_DIR_USR_SBIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_RDATE) += rdate.o
+
+//usage:#define rdate_trivial_usage
+//usage:       "[-s/-p] HOST"
+//usage:#define rdate_full_usage "\n\n"
+//usage:       "Set and print time from HOST using RFC 868\n"
+//usage:     "\n       -s      Only set system time"
+//usage:     "\n       -p      Only print time"
 
 #include "libbb.h"
 
@@ -22,49 +41,66 @@ static time_t askremotedate(const char *host)
        uint32_t nett;
        int fd;
 
-       /* Add a timeout for dead or inaccessible servers */
+       /* Timeout for dead or inaccessible servers */
        alarm(10);
        signal(SIGALRM, socket_timeout);
 
-       fd = create_and_connect_stream_or_die(host, bb_lookup_port("time", "tcp", 37));
+       fd = create_and_connect_stream_or_die(host, bb_lookup_std_port("time", "tcp", 37));
 
-       if (safe_read(fd, (void *)&nett, 4) != 4)    /* read time from server */
-               bb_error_msg_and_die("%s did not send the complete time", host);
-       close(fd);
+       if (safe_read(fd, &nett, 4) != 4)    /* read time from server */
+               bb_error_msg_and_die("%s: %s", host, "short read");
+       if (ENABLE_FEATURE_CLEAN_UP)
+               close(fd);
 
-       /* convert from network byte order to local byte order.
-        * RFC 868 time is the number of seconds
-        * since 00:00 (midnight) 1 January 1900 GMT
-        * the RFC 868 time 2,208,988,800 corresponds to 00:00  1 Jan 1970 GMT
-        * Subtract the RFC 868 time to get Linux epoch
+       /* Convert from network byte order to local byte order.
+        * RFC 868 time is seconds since 1900-01-01 00:00 GMT.
+        * RFC 868 time 2,208,988,800 corresponds to 1970-01-01 00:00 GMT.
+        * Subtract the RFC 868 time to get Linux epoch.
         */
-
-       return ntohl(nett) - RFC_868_BIAS;
+       nett = ntohl(nett) - RFC_868_BIAS;
+
+       if (sizeof(time_t) > 4) {
+               /* Now we have 32-bit lsb of a wider time_t
+                * Imagine that  nett =   0x00000001,
+                * current time  cur = 0x123ffffffff.
+                * Assuming our time is not some 40 years off,
+                * remote time must be 0x12400000001.
+                * Need to adjust our time by (int32_t)(nett - cur).
+                */
+               time_t cur = time(NULL);
+               int32_t adjust = (int32_t)(nett - (uint32_t)cur);
+               return cur + adjust;
+       }
+       /* This is not going to work, but what can we do */
+       return (time_t)nett;
 }
 
 int rdate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int rdate_main(int argc UNUSED_PARAM, char **argv)
 {
        time_t remote_time;
-       unsigned long flags;
+       unsigned flags;
 
-       opt_complementary = "-1";
-       flags = getopt32(argv, "sp");
+       flags = getopt32(argv, "^" "sp" "\0" "-1");
 
        remote_time = askremotedate(argv[optind]);
 
-       if ((flags & 2) == 0) {
-               time_t current_time;
+       /* Manpages of various Unixes are confusing. What happens is:
+        * (no opts) set and print time
+        * -s: set time ("do not print the time")
+        * -p: print time ("do not set, just print the remote time")
+        * -sp: print time (that's what we do, not sure this is right)
+        */
 
-               time(&current_time);
-               if (current_time == remote_time)
+       if (!(flags & 2)) { /* no -p (-s may be present) */
+               if (time(NULL) == remote_time)
                        bb_error_msg("current time matches remote time");
                else
                        if (stime(&remote_time) < 0)
                                bb_perror_msg_and_die("can't set time of day");
        }
 
-       if ((flags & 1) == 0)
+       if (flags != 1) /* not lone -s */
                printf("%s", ctime(&remote_time));
 
        return EXIT_SUCCESS;