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The following code snippet provides a crude timer mechanism for file read failures, somewhat along the lines of what Re: Redirecting stdout/stderr to pipe achieves for commands. The real code will run on many systems and I deem the timeout as necessary, although I know read failures are uncommon.

I eliminated the use of sysread+select due to the fact that I need @$outref populated line-by-line (whereas sysread uses buffers). I also do not have any real ideas on encoding. Can anyone make any improvement suggestions or is this ok?

Niel

UPDATE: fixed an endless loop in the example.

#!/usr/bin/perl -w use strict; use IO::Select; use Symbol qw(gensym); my $g_verbose = 1; my $g_pid; my $g_stop; my $g_timeout = 2; #for test purposes my $g_did_run; my $g_max_cmd_size = 2_000_000; my $g_max_file_size = 2_000_000; my %g_pids; sub read_stat($$$) { my ($file,$rcref,$statref) = @_; @$statref = stat($file); if ( $#$statref < 0 ) { print "Stat of file '$file' failed: $!\n"; $$rcref = 1; } else { $$rcref = 0; } return $$rcref; } sub read_file($$$$$) { my ($file,$encoding,$rcref,$outref,$statref) = @_; @$outref = (); my $outbytes = 0; $g_stop = 0; # die if timeout occurs! local $SIG{ALRM} = sub { print "File \'$file\' collection reached deadline after $g_timeo +ut secs.\n"; die "Exiting - a read operation timed out!\n"; $g_stop = 1; }; alarm($g_timeout); if ( !defined($encoding) ) { $encoding = 'text/plain'; } if ( $encoding ne 'text/plain' ) { print "Error: Can't collect file '$file' - '$encoding' encoding +is not supported.\n"; $$rcref = -2; return $$rcref; } if ( $g_verbose ) { print "Collecting '$file'.\n"; } read_stat($file,$rcref,$statref); if ( $$rcref != 0 ) { return undef; } if ( !open(IFILE,"<$file") ) { print "Open of file '$file' failed: $!\n"; return undef; } # read data into @$outref (line by line). alarm prevents timeout. while (!$g_stop) { last if (eof(IFILE)); my $line = <IFILE>; chomp $line; push @$outref, $line; # for test purposes - make it timeout! sleep 5; $outbytes += length($line); if ($outbytes >= $g_max_file_size) { print "Maximum file size reached after $outbytes bytes\n"; last; alarm(0); close(IFILE); if (!$g_stop) { $$rcref = 0; } else { $$rcref = -1; } return $$rcref; } #MAIN my $file = '/etc/hosts'; my $encoding = 'text/plain'; my $rc; my (@cmdout,@stat); $rc = read_file($file,$encoding,\$rc,\@cmdout,\@stat); print "Collected $file (rc=$rc)\n";

In reply to file read timeout by 0xbeef

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