[MacPorts] #60509: Upgrading ports sometimes breaks internet connection

[MacPorts]

#60509: Upgrading ports sometimes breaks internet connection
---------------------+--------------------
  Reporter:  iEFdev  |      Owner:  (none)
      Type:  defect  |     Status:  new
  Priority:  Normal  |  Milestone:
 Component:  base    |    Version:  2.6.2
Resolution:          |   Keywords:
      Port:          |
---------------------+--------------------
Changes (by ryandesign):

 * cc: jmroot (added)


Comment:

 Looking back at the kernel panic logs I've saved from our 10.6 i386
 builder, all of them are either in `ping` or `grep` or `cut`.

 When MacPorts determines a server's ping time, it does so by running `ping
 -noq -c3 -t3 $host | grep round-trip | cut -d / -f 5`.

 The code is in `proc portfetch::sortsites` in https://github.com/macports
 /macports-base/blob/master/src/port1.0/fetch_common.tcl.

 MacPorts spawns `ping` and `grep` and `cut` processes for each host whose
 pingtime it needs to check. It doesn't need to check those that it checked
 within the past 24 hours, but if you haven't used MacPorts in over a day,
 then it needs to recheck them all.

 An idea about why perl modules specifically might trigger the problem is
 that our list of perl cpan mirror sites is very large. There are currently
 191 hosts in the list. Add to that the 16 MacPorts mirrors and that's 207
 hosts to check all at once, for which MacPorts spawns 621 simultaneous
 processes. Each process surely needs at least one file descriptor. It
 could be that this is exceeding the number of available file descriptors,
 especially if your computer has many other open files already and/or has
 been online for awhile and you've been running programs that have leaked
 file descriptors (opened them but forgot to close them). It's possible
 that MacPorts itself is still leaking file descriptors somewhere.
 [ticket:50986 One such bug] was already fixed previously. And if you are
 running out of file descriptors, then it is not at all surprising that
 Internet access, the ability to open programs and read and write files,
 and pretty much everything else about the computer would cease to
 function.

 Possible solutions:

 1. We could trim the list of perl cpan [https://github.com/macports
 /macports-ports/blob/master/_resources/port1.0/fetch/mirror_sites.tcl
 mirrors] to a more reasonable number.
 2. MacPorts base could spawn only a `ping` process for each host and
 perform the equivalent of the `grep` and `cut` commands using Tcl string
 processing.
 3. MacPorts base could limit the number of hosts that it checks
 simultaneously.

-- 
Ticket URL: <https://trac.macports.org/ticket/60509#comment:4>
MacPorts <https://www.macports.org/>
Ports system for macOS