use strict;
no strict 'refs'; # because users pass me bareword filehandles
-use vars qw($VERSION @ISA @EXPORT $Fh $Me);
+our ($VERSION, @ISA, @EXPORT);
-require 5.001;
require Exporter;
use Carp;
-use Symbol 'qualify';
+use Symbol qw(gensym qualify);
-$VERSION = 1.0101;
+$VERSION = 1.0103;
@ISA = qw(Exporter);
@EXPORT = qw(open3);
$pid = open3(\*WTRFH, \*RDRFH, \*ERRFH,
'some cmd and args', 'optarg', ...);
+ my($wtr, $rdr, $err);
+ $pid = open3($wtr, $rdr, $err,
+ 'some cmd and args', 'optarg', ...);
+
=head1 DESCRIPTION
Extremely similar to open2(), open3() spawns the given $cmd and
connects RDRFH for reading, WTRFH for writing, and ERRFH for errors. If
-ERRFH is '', or the same as RDRFH, then STDOUT and STDERR of the child are
-on the same file handle. The WTRFH will have autoflush turned on.
+ERRFH is false, or the same file descriptor as RDRFH, then STDOUT and
+STDERR of the child are on the same filehandle. The WTRFH will have
+autoflush turned on.
-If WTRFH begins with "E<lt>&", then WTRFH will be closed in the parent, and
+If WTRFH begins with C<< <& >>, then WTRFH will be closed in the parent, and
the child will read from it directly. If RDRFH or ERRFH begins with
-"E<gt>&", then the child will send output directly to that file handle.
+C<< >& >>, then the child will send output directly to that filehandle.
In both cases, there will be a dup(2) instead of a pipe(2) made.
-If you try to read from the child's stdout writer and their stderr
-writer, you'll have problems with blocking, which means you'll
-want to use select(), which means you'll have to use sysread() instead
-of normal stuff.
+If either reader or writer is the null string, this will be replaced
+by an autogenerated filehandle. If so, you must pass a valid lvalue
+in the parameter slot so it can be overwritten in the caller, or
+an exception will be raised.
-open3() returns the process ID of the child process. It doesn't return on
-failure: it just raises an exception matching C</^open3:/>.
+The filehandles may also be integers, in which case they are understood
+as file descriptors.
-=head1 WARNING
+open3() returns the process ID of the child process. It doesn't return on
+failure: it just raises an exception matching C</^open3:/>. However,
+C<exec> failures in the child are not detected. You'll have to
+trap SIGPIPE yourself.
-It will not create these file handles for you. You have to do this
-yourself. So don't pass it empty variables expecting them to get filled
-in for you.
+open3() does not wait for and reap the child process after it exits.
+Except for short programs where it's acceptable to let the operating system
+take care of this, you need to do this yourself. This is normally as
+simple as calling C<waitpid $pid, 0> when you're done with the process.
+Failing to do this can result in an accumulation of defunct or "zombie"
+processes. See L<perlfunc/waitpid> for more information.
-Additionally, this is very dangerous as you may block forever. It
-assumes it's going to talk to something like B<bc>, both writing to it
-and reading from it. This is presumably safe because you "know" that
-commands like B<bc> will read a line at a time and output a line at a
-time. Programs like B<sort> that read their entire input stream first,
+If you try to read from the child's stdout writer and their stderr
+writer, you'll have problems with blocking, which means you'll want
+to use select() or the IO::Select, which means you'd best use
+sysread() instead of readline() for normal stuff.
+
+This is very dangerous, as you may block forever. It assumes it's
+going to talk to something like B<bc>, both writing to it and reading
+from it. This is presumably safe because you "know" that commands
+like B<bc> will read a line at a time and output a line at a time.
+Programs like B<sort> that read their entire input stream first,
however, are quite apt to cause deadlock.
The big problem with this approach is that if you don't have control
what it does with pipe buffering. Thus you can't just open a pipe to
C<cat -v> and continually read and write a line from it.
+=head1 WARNING
+
+The order of arguments differs from that of open2().
+
=cut
# &open3: Marc Horowitz <marc@mit.edu>
# derived mostly from &open2 by tom christiansen, <tchrist@convex.com>
# fixed for 5.001 by Ulrich Kunitz <kunitz@mai-koeln.com>
+# ported to Win32 by Ron Schmidt, Merrill Lynch almost ended my career
+# fixed for autovivving FHs, tchrist again
+# allow fd numbers to be used, by Frank Tobin
#
# $Id: open3.pl,v 1.1 1993/11/23 06:26:15 marc Exp $
#
# rdr or wtr are null
# a system call fails
-$Fh = 'FHOPEN000'; # package static in case called more than once
-$Me = 'open3 (bug)'; # you should never see this, it's always localized
+our $Me = 'open3 (bug)'; # you should never see this, it's always localized
# Fatal.pm needs to be fixed WRT prototypes.
close $_[0] or croak "$Me: close($_[0]) failed: $!";
}
-my $do_spawn = $^O eq 'os2';
+sub fh_is_fd {
+ return $_[0] =~ /\A=?(\d+)\z/;
+}
+
+sub xfileno {
+ return $1 if $_[0] =~ /\A=?(\d+)\z/; # deal with fh just being an fd
+ return fileno $_[0];
+}
+
+my $do_spawn = $^O eq 'os2' || $^O eq 'MSWin32';
sub _open3 {
local $Me = shift;
my($package, $dad_wtr, $dad_rdr, $dad_err, @cmd) = @_;
my($dup_wtr, $dup_rdr, $dup_err, $kidpid);
- $dad_wtr or croak "$Me: wtr should not be null";
- $dad_rdr or croak "$Me: rdr should not be null";
- $dad_err = $dad_rdr if ($dad_err eq '');
+ # simulate autovivification of filehandles because
+ # it's too ugly to use @_ throughout to make perl do it for us
+ # tchrist 5-Mar-00
+
+ unless (eval {
+ $dad_wtr = $_[1] = gensym unless defined $dad_wtr && length $dad_wtr;
+ $dad_rdr = $_[2] = gensym unless defined $dad_rdr && length $dad_rdr;
+ 1; })
+ {
+ # must strip crud for croak to add back, or looks ugly
+ $@ =~ s/(?<=value attempted) at .*//s;
+ croak "$Me: $@";
+ }
+
+ $dad_err ||= $dad_rdr;
$dup_wtr = ($dad_wtr =~ s/^[<>]&//);
$dup_rdr = ($dad_rdr =~ s/^[<>]&//);
$dup_err = ($dad_err =~ s/^[<>]&//);
- # force unqualified filehandles into callers' package
- $dad_wtr = qualify $dad_wtr, $package;
- $dad_rdr = qualify $dad_rdr, $package;
- $dad_err = qualify $dad_err, $package;
+ # force unqualified filehandles into caller's package
+ $dad_wtr = qualify $dad_wtr, $package unless fh_is_fd($dad_wtr);
+ $dad_rdr = qualify $dad_rdr, $package unless fh_is_fd($dad_rdr);
+ $dad_err = qualify $dad_err, $package unless fh_is_fd($dad_err);
- my $kid_rdr = ++$Fh;
- my $kid_wtr = ++$Fh;
- my $kid_err = ++$Fh;
+ my $kid_rdr = gensym;
+ my $kid_wtr = gensym;
+ my $kid_err = gensym;
xpipe $kid_rdr, $dad_wtr if !$dup_wtr;
xpipe $dad_rdr, $kid_wtr if !$dup_rdr;
# If she wants to dup the kid's stderr onto her stdout I need to
# save a copy of her stdout before I put something else there.
if ($dad_rdr ne $dad_err && $dup_err
- && fileno($dad_err) == fileno(STDOUT)) {
- my $tmp = ++$Fh;
+ && xfileno($dad_err) == fileno(STDOUT)) {
+ my $tmp = gensym;
xopen($tmp, ">&$dad_err");
$dad_err = $tmp;
}
if ($dup_wtr) {
- xopen \*STDIN, "<&$dad_wtr" if fileno(STDIN) != fileno($dad_wtr);
+ xopen \*STDIN, "<&$dad_wtr" if fileno(STDIN) != xfileno($dad_wtr);
} else {
xclose $dad_wtr;
- xopen \*STDIN, "<&$kid_rdr";
- xclose $kid_rdr;
+ xopen \*STDIN, "<&=" . fileno $kid_rdr;
}
if ($dup_rdr) {
- xopen \*STDOUT, ">&$dad_rdr" if fileno(STDOUT) != fileno($dad_rdr);
+ xopen \*STDOUT, ">&$dad_rdr" if fileno(STDOUT) != xfileno($dad_rdr);
} else {
xclose $dad_rdr;
- xopen \*STDOUT, ">&$kid_wtr";
- xclose $kid_wtr;
+ xopen \*STDOUT, ">&=" . fileno $kid_wtr;
}
if ($dad_rdr ne $dad_err) {
if ($dup_err) {
- xopen \*STDERR, ">&$dad_err"
- if fileno(STDERR) != fileno($dad_err);
+ # I have to use a fileno here because in this one case
+ # I'm doing a dup but the filehandle might be a reference
+ # (from the special case above).
+ xopen \*STDERR, ">&" . xfileno($dad_err)
+ if fileno(STDERR) != xfileno($dad_err);
} else {
xclose $dad_err;
- xopen \*STDERR, ">&$kid_err";
- xclose $kid_err;
+ xopen \*STDERR, ">&=" . fileno $kid_err;
}
} else {
xopen \*STDERR, ">&STDOUT" if fileno(STDERR) != fileno(STDOUT);
}
local($")=(" ");
- exec @cmd
- or croak "open3: exec of @cmd failed";
+ exec @cmd # XXX: wrong process to croak from
+ or croak "$Me: exec of @cmd failed";
} elsif ($do_spawn) {
# All the bookkeeping of coincidence between handles is
# handled in spawn_with_handles.
my @close;
if ($dup_wtr) {
- $kid_rdr = $dad_wtr;
- push @close, \*{$kid_rdr};
+ $kid_rdr = \*{$dad_wtr};
+ push @close, $kid_rdr;
} else {
- push @close, \*{$dad_wtr}, \*{$kid_rdr};
+ push @close, \*{$dad_wtr}, $kid_rdr;
}
if ($dup_rdr) {
- $kid_wtr = $dad_rdr;
- push @close, \*{$kid_wtr};
+ $kid_wtr = \*{$dad_rdr};
+ push @close, $kid_wtr;
} else {
- push @close, \*{$dad_rdr}, \*{$kid_wtr};
+ push @close, \*{$dad_rdr}, $kid_wtr;
}
if ($dad_rdr ne $dad_err) {
if ($dup_err) {
- $kid_err = $dad_err ;
- push @close, \*{$kid_err};
+ $kid_err = \*{$dad_err};
+ push @close, $kid_err;
} else {
- push @close, \*{$dad_err}, \*{$kid_err};
+ push @close, \*{$dad_err}, $kid_err;
}
} else {
$kid_err = $kid_wtr;
require IO::Pipe;
$kidpid = eval {
spawn_with_handles( [ { mode => 'r',
- open_as => \*{$kid_rdr},
+ open_as => $kid_rdr,
handle => \*STDIN },
{ mode => 'w',
- open_as => \*{$kid_wtr},
+ open_as => $kid_wtr,
handle => \*STDOUT },
{ mode => 'w',
- open_as => \*{$kid_err},
+ open_as => $kid_err,
handle => \*STDERR },
], \@close, @cmd);
};
- die "open3: $@" if $@;
+ die "$Me: $@" if $@;
}
xclose $kid_rdr if !$dup_wtr;
$fd->{handle}->fdopen($saved{fileno $fd->{open_as}} || $fd->{open_as},
$fd->{mode});
}
- # Stderr may be redirected below, so we save the err text:
- foreach $fd (@$close_in_child) {
- fcntl($fd, Fcntl::F_SETFD(), 1) or push @errs, "fcntl $fd: $!"
- unless $saved{fileno $fd}; # Do not close what we redirect!
+ unless ($^O eq 'MSWin32') {
+ # Stderr may be redirected below, so we save the err text:
+ foreach $fd (@$close_in_child) {
+ fcntl($fd, Fcntl::F_SETFD(), 1) or push @errs, "fcntl $fd: $!"
+ unless $saved{fileno $fd}; # Do not close what we redirect!
+ }
}
unless (@errs) {