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timedated: gather timezone from /etc/localtime sym target

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/etc/localtime -> /usr/share/zoneinfo/...

or

/etc/localtime -> ../usr/share/zoneinfo/...

(note, ../usr is not the same if /etc is a symlink, as this isn't
using canonicalize_file_name())

keep other method for now, consider dropping later.

Supporting relative links here are problematic as timezones in
/usr/share/zoneinfo are often themselves symlinks (and symlinks to
symlinks), so this implamentation only supports absolute symlinks
"/usr/share/zoneinfo/" and relative symlinks starting with
"../usr/share/zoneinfo/"

>From TODO (kay sievers):
* kill /etc/timezone handling entirely? What does it provide?
  - /etc/localtime carries the same information already:
      $ ls -l /etc/localtime; cat /etc/timezone
      lrwxrwxrwx 1 root root 33 Jul 27 09:55 /etc/localtime -> /usr/share/zoneinfo/Europe/Berlin
      Europe/Berlin
  - systemd enforces /usr to be available at bootup, so we can
    enforce the use of the symlink
This commit is contained in:
Shawn Landden 2012-08-21 23:11:26 -07:00 committed by Lennart Poettering
parent cdefbd6aeb
commit 92c4ef2d35
1 changed files with 42 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
src/timedate/timedated.c
View File

@ -76,6 +76,9 @@
BUS_GENERIC_INTERFACES_LIST \
"org.freedesktop.timedate1\0"
/* Must start and end with '/' */
#define ZONEINFO_PATH "/usr/share/zoneinfo/"
const char timedate_interface[] _introspect_("timedate1") = INTERFACE;
typedef struct TZ {
@ -129,7 +132,7 @@ static bool valid_timezone(const char *name) {
if (slash)
return false;
t = strappend("/usr/share/zoneinfo/", name);
t = strappend(ZONEINFO_PATH, name);
if (!t)
return false;
@ -153,17 +156,17 @@ static void verify_timezone(void) {
if (!tz.zone)
return;
p = strappend("/usr/share/zoneinfo/", tz.zone);
p = strappend(ZONEINFO_PATH, tz.zone);
if (!p) {
log_oom();
return;
}
j = read_full_file("/etc/localtime", &a, &l);
k = read_full_file(p, &b, &q);
free(p);
j = read_full_file("/etc/localtime", &a, &l);
if (j < 0 || k < 0 || l != q || memcmp(a, b, l)) {
log_warning("/etc/localtime and /etc/timezone out of sync.");
free(tz.zone);
@ -176,9 +179,34 @@ static void verify_timezone(void) {
static int read_data(void) {
int r;
char *t = NULL;
free_data();
r = readlink_malloc("/etc/localtime", &t);
if (r < 0) {
if (r == -EINVAL)
log_warning("/etc/localtime should be a symbolic link to a timezone data file in " ZONEINFO_PATH);
else
log_warning("Failed to get target of %s: %s", "/etc/localtime", strerror(-r));
} else {
/* we only support the trivial relative link of (/etc/)..$ABSOLUTE */
int rel_link_offset = startswith(t, "..") ? strlen("..") : 0;
if (!startswith(t + rel_link_offset, ZONEINFO_PATH))
log_warning("/etc/localtime should be a symbolic link to a timezone data file in " ZONEINFO_PATH);
else {
tz.zone = strdup(t + rel_link_offset + strlen(ZONEINFO_PATH));
free(t);
if (!tz.zone)
return log_oom();
goto have_timezone;
}
}
free(t);
r = read_one_line_file("/etc/timezone", &tz.zone);
if (r < 0) {
if (r != -ENOENT)
@ -194,6 +222,7 @@ static int read_data(void) {
#endif
}
have_timezone:
if (isempty(tz.zone)) {
free(tz.zone);
tz.zone = NULL;
@ -209,6 +238,7 @@ static int read_data(void) {
static int write_data_timezone(void) {
int r = 0;
char *p;
struct stat st;
if (!tz.zone) {
if (unlink("/etc/timezone") < 0 && errno != ENOENT)
@ -220,19 +250,21 @@ static int write_data_timezone(void) {
return r;
}
p = strappend("/usr/share/zoneinfo/", tz.zone);
p = strappend(ZONEINFO_PATH, tz.zone);
if (!p)
return log_oom();
r = symlink_or_copy_atomic(p, "/etc/localtime");
r = symlink(p, "/etc/localtime");
free(p);
if (r < 0)
return r;
return -errno;
r = write_one_line_file_atomic("/etc/timezone", tz.zone);
if (r < 0)
return r;
if (stat("/etc/timezone", &st) == 0 && S_ISREG(st.st_mode)) {
r = write_one_line_file_atomic("/etc/timezone", tz.zone);
if (r < 0)
return r;
}
return 0;
}