+\f
+############################################################################
+#
+# Pick images by waiting for driftnet to populate a temp dir with files.
+# Requires driftnet version 0.1.5 or later.
+# (Driftnet is a program by Chris Lightfoot that sniffs your local ethernet
+# for images being downloaded by others.)
+# Driftnet/webcollage integration by jwz.
+#
+############################################################################
+
+# driftnet
+sub pick_from_driftnet {
+ my ( $timeout ) = @_;
+
+ my $id = $driftnet_magic;
+ my $dir = $driftnet_dir;
+ my $start = time;
+ my $now;
+
+ error ("\$driftnet_dir unset?") unless ($dir);
+ $dir =~ s@/+$@@;
+
+ error ("$dir unreadable") unless (-d "$dir/.");
+
+ $timeout = $http_timeout unless ($timeout);
+ $last_search = $id;
+
+ while ($now = time, $now < $start + $timeout) {
+ local *DIR;
+ opendir (DIR, $dir) || error ("$dir: $!");
+ while (my $file = readdir(DIR)) {
+ next if ($file =~ m/^\./);
+ $file = "$dir/$file";
+ closedir DIR;
+ LOG ($verbose_load, "picked file $file ($id)");
+ return ($id, $file);
+ }
+ closedir DIR;
+ }
+ LOG (($verbose_net || $verbose_load), "timed out for $id");
+ return ();
+}
+
+
+sub get_driftnet_file {
+ my ($file) = @_;
+
+ error ("\$driftnet_dir unset?") unless ($driftnet_dir);
+
+ my $id = $driftnet_magic;
+ my $re = qr/$driftnet_dir/;
+ error ("$id: $file not in $driftnet_dir?")
+ unless ($file =~ m@^$re@o);
+
+ local *IN;
+ open (IN, $file) || error ("$id: $file: $!");
+ my $body = '';
+ while (<IN>) { $body .= $_; }
+ close IN;
+ unlink ($file);
+ return ($id, $body);
+}
+
+
+sub spawn_driftnet {
+ my ($cmd) = @_;
+
+ # make a directory to use.
+ while (1) {
+ my $tmp = $ENV{TEMPDIR} || "/tmp";
+ $driftnet_dir = sprintf ("$tmp/driftcollage-%08x", rand(0xffffffff));
+ LOG ($verbose_exec, "mkdir $driftnet_dir");
+ last if mkdir ($driftnet_dir, 0700);
+ }
+
+ if (! ($cmd =~ m/\s/)) {
+ # if the command didn't have any arguments in it, then it must be just
+ # a pointer to the executable. Append the default args to it.
+ my $dargs = $default_driftnet_cmd;
+ $dargs =~ s/^[^\s]+//;
+ $cmd .= $dargs;
+ }
+
+ # point the driftnet command at our newly-minted private directory.
+ #
+ $cmd .= " -d $driftnet_dir";
+ $cmd .= ">/dev/null" unless ($verbose_exec);
+
+ my $pid = fork();
+ if ($pid < 0) { error ("fork: $!\n"); }
+ if ($pid) {
+ # parent fork
+ push @pids_to_kill, $pid;
+ LOG ($verbose_exec, "forked for \"$cmd\"");
+ } else {
+ # child fork
+ nontrapping_system ($cmd) || error ("exec: $!");
+ }
+
+ # wait a bit, then make sure the process actually started up.
+ #
+ sleep (1);
+ error ("pid $pid failed to start \"$cmd\"")
+ unless (1 == kill (0, $pid));
+}
+