[systemd-devel] [PATCH] timedated: add --timezone option to set the default timezone

[Juho Son]

This option could changes the default system's time zone.
The default time zone is /etc/localtime. If we want to use
the specific path, we could use this option.

Change-Id: Iab7d8b2530d8632f57f3700fd6b5860242aee423
---
 src/timedate/timedated.c |   79 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 66 insertions(+), 13 deletions(-)

diff --git a/src/timedate/timedated.c b/src/timedate/timedated.c
index c4a797a..1a351bd 100644
--- a/src/timedate/timedated.c
+++ b/src/timedate/timedated.c
@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
+#include <getopt.h>
 
 #include "sd-id128.h"
 #include "sd-messages.h"
@@ -50,6 +51,8 @@ typedef struct Context {
         Hashmap *polkit_registry;
 } Context;
 
+static const char *arg_tz = "/etc/localtime";
+
 static void context_reset(Context *c) {
         assert(c);
 
@@ -115,7 +118,7 @@ static bool valid_timezone(const char *name) {
         return true;
 }
 
-static int context_read_data(Context *c) {
+static int context_read_data(Context *c, const char *tz) {
         _cleanup_free_ char *t = NULL;
         int r;
 
@@ -123,12 +126,12 @@ static int context_read_data(Context *c) {
 
         context_reset(c);
 
-        r = readlink_malloc("/etc/localtime", &t);
+        r = readlink_malloc(tz, &t);
         if (r < 0) {
                 if (r == -EINVAL)
-                        log_warning("/etc/localtime should be a symbolic link to a timezone data file in /usr/share/zoneinfo/.");
+                        log_warning("%s should be a symbolic link to a timezone data file in /usr/share/zoneinfo/.", tz);
                 else
-                        log_warning("Failed to get target of /etc/localtime: %s", strerror(-r));
+                        log_warning("Failed to get target of %s: %s", tz, strerror(-r));
         } else {
                 const char *e;
 
@@ -137,7 +140,7 @@ static int context_read_data(Context *c) {
                         e = path_startswith(t, "../usr/share/zoneinfo/");
 
                 if (!e)
-                        log_warning("/etc/localtime should be a symbolic link to a timezone data file in /usr/share/zoneinfo/.");
+                        log_warning("%s should be a symbolic link to a timezone data file in /usr/share/zoneinfo/.", tz);
                 else {
                         c->zone = strdup(e);
                         if (!c->zone)
@@ -158,24 +161,24 @@ have_timezone:
         return 0;
 }
 
-static int context_write_data_timezone(Context *c) {
+static int context_write_data_timezone(Context *c, const char *tz) {
         _cleanup_free_ char *p = NULL;
         int r = 0;
 
         assert(c);
 
         if (isempty(c->zone)) {
-                if (unlink("/etc/localtime") < 0 && errno != ENOENT)
+                if (unlink(tz) < 0 && errno != ENOENT)
                         r = -errno;
 
                 return r;
         }
 
-        p = strappend("../usr/share/zoneinfo/", c->zone);
+        p = strappend("/usr/share/zoneinfo/", c->zone);
         if (!p)
                 return log_oom();
 
-        r = symlink_atomic(p, "/etc/localtime");
+        r = symlink_atomic(p, tz);
         if (r < 0)
                 return r;
 
@@ -540,7 +543,7 @@ static int method_set_timezone(sd_bus *bus, sd_bus_message *m, void *userdata, s
         c->zone = t;
 
         /* 1. Write new configuration file */
-        r = context_write_data_timezone(c);
+        r = context_write_data_timezone(c, arg_tz);
         if (r < 0) {
                 log_error("Failed to set timezone: %s", strerror(-r));
                 return sd_bus_error_set_errnof(error, r, "Failed to set timezone: %s", strerror(-r));
@@ -809,6 +812,56 @@ static int connect_bus(Context *c, sd_event *event, sd_bus **_bus) {
         return 0;
 }
 
+static int help(void) {
+
+        printf("%s [OPTIONS...] COMMAND ...\n\n"
+                        "Control the system time and related settings.\n\n"
+                        "  -h --help                Show this help\n"
+                        "     --timezone=PATH       Set the default timezone\n",
+                        program_invocation_short_name);
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_TZ = 0x100
+        };
+
+        static const struct option options[] = {
+                { "help",                no_argument,       NULL, 'h'                     },
+                { "timezone",            required_argument, NULL, ARG_TZ                  },
+                {}
+        };
+
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h:", options, NULL)) >= 0) {
+
+                switch (c) {
+
+                        case 'h':
+                                return help();
+
+                        case ARG_TZ:
+                                arg_tz = optarg;
+                                break;
+
+                        case '?':
+                                return -EINVAL;
+
+                        default:
+                                assert_not_reached("Unhandled option");
+                }
+        }
+
+        return 1;
+}
+
 int main(int argc, char *argv[]) {
         Context context = {
                 .zone = NULL,
@@ -827,8 +880,8 @@ int main(int argc, char *argv[]) {
 
         umask(0022);
 
-        if (argc != 1) {
-                log_error("This program takes no arguments.");
+        r = parse_argv(argc, argv);
+        if (r <= 0) {
                 r = -EINVAL;
                 goto finish;
         }
@@ -845,7 +898,7 @@ int main(int argc, char *argv[]) {
         if (r < 0)
                 goto finish;
 
-        r = context_read_data(&context);
+        r = context_read_data(&context, arg_tz);
         if (r < 0) {
                 log_error("Failed to read timezone data: %s", strerror(-r));
                 goto finish;
-- 
1.7.9.5