396521 - FTP file dates have wrong year for files with timestamps in the future

Status: RESOLVED WONTFIX

(Core Graveyard :: Networking: FTP, defect)

Description

[Reed Loden [:reed]]

If a file listed in the FTP file listings has a timestamp from the "future", Firefox will show the previous year (2006 in this case) instead of the current year (2007 in this case).

File: firefox-3.0a8pre.en-US.linux-i686.tar.bz2   8856 KB   09/18/2006   03:45:00 AM

This seems to be because it is not yet 09/18 in my current timezone (still 09/17), so the date parser falls back onto the last time 09/18 actually existed for me (maybe?). For people that the day is 09/18, the correct year (2007) is used.

If you do 'ls' in an ftp session with ftp.mozilla.org for this file:
ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
-rwxrwxr-x    1 ftp      ftp       9068359 Sep 18 03:45 firefox-3.0a8pre.en-US.linux-i686.tar.bz2

Note that it shows the time instead of the year. If it is older than 6 months, it shows the year instead:
drwxr-xr-x    3 ftp      ftp          4096 Oct 25  2005 pub

If the timestamp to be displayed is between 'now' and 'six months before
now', then the date/time display is used.  If the time is outside that
window, then the date/year display is used.

Expected result: Firefox should display the correct year for the file even if the time is in the future.

Comment 1

[Dave Miller [:justdave]]

note that the time is only in the future because the FTP server is sending the time in UTC, and Firefox is apparently interpreting it as the local timezone.

Comment 2

[Dave Miller [:justdave]]

for this particular use case (timezone differences) it'd probably be sufficient to assume the time is in the future if it looks like more than 363 days ago.  The 6-months thing seems to be the practice on Linux, but who knows if that's universal across FTP servers.

Comment 3

[Dave Miller [:justdave]]

vsftpd (our FTP server) does this:

  const char* p_date_format = "%b %d %H:%M";
  if (!use_localtime)
  {
    p_tm = gmtime(&p_stat->st_mtime);
  }
  else
  {
    p_tm = localtime(&p_stat->st_mtime);
  }
  /* Is this a future or 6 months old date? If so, we drop to year format */
  if (p_stat->st_mtime > local_time ||
      (local_time - p_stat->st_mtime) > 60*60*24*182)
  {
    p_date_format = "%b %d  %Y";
  }

Note that it's 6 months, and that whether to use GMT or local timezone is a config option (so by no means is the timezone being GMT going to be universal).

/bin/ls, whose output is what is modeled by most UNIX ftp servers, does this:

      six_months_ago = current_time - 31556952 / 2;
      recent = (six_months_ago <= when
		&& (when < current_time
		    || (when == current_time && when_ns <= current_time_ns)));
      fmt = long_time_format[recent];

where long_time_format is defined as:

static char const *long_time_format[2] =
  {
    N_("%b %e  %Y"),
    N_("%b %e %H:%M")
  };

Comment 4

[John O'Duinn [:joduinn] (please use "needinfo?" flag)]

From IRC discussion, is this a dup of bug#61235 (yeah, a really old 5 digit bug)?!

Comment 5

[Reed Loden [:reed]]

(In reply to comment #4)
> From IRC discussion, is this a dup of bug#61235 (yeah, a really old 5 digit
> bug)?!

That bug is VERIFIED FIXED, and the issue mentioned in this bug is still clearly present, so it is not a duplicate.

Comment 6

[Doug Turner (:dougt)]

the code in question is here:

http://lxr.mozilla.org/mozilla1.8/source/netwerk/streamconv/converters/ParseFTPList.cpp#1152

if you look back a bit in blame, ignoring darin's last check-in, the underlying code was apart of an initial import of Cyrus Patel's LIST Parser from 2002.

I am not really sure why we need to decrement the year if the month and date returned by the FTP is greater than today's month and date.

Comment 7

[Doug Turner (:dougt)]

Cyrus, do you remember why you had to adjust the year based on what month and date the server returned?

Comment 8

[Doug Turner (:dougt)]

mass reassigning to nobody.

Comment 9

[Patrick McManus [:mcmanus]]

only critical fixes now

Comment 10

[Patrick McManus [:mcmanus]]

for ftp, that is :)