diff options
Diffstat (limited to 'lib/open3.pl')
| -rw-r--r-- | lib/open3.pl | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/lib/open3.pl b/lib/open3.pl new file mode 100644 index 0000000000..f3d8138879 --- /dev/null +++ b/lib/open3.pl @@ -0,0 +1,105 @@ +# &open3: Marc Horowitz <marc@mit.edu> +# derived mostly from &open2 by tom christiansen, <tchrist@convex.com> +# +# usage: $pid = open3('wtr', 'rdr', 'err' 'some cmd and args', 'optarg', ...); +# +# spawn the given $cmd and connect rdr for +# reading, wtr for writing, and err for errors. +# if err is '', or the same as rdr, then stdout and +# stderr of the child are on the same fh. returns pid +# of child, or 0 on failure. + + +# if wtr begins with '>&', then wtr will be closed in the parent, and +# the child will read from it directly. if rdr or err begins with +# '>&', then the child will send output directly to that fd. In both +# cases, there will be a dup() instead of a pipe() made. + + +# WARNING: this is dangerous, as you may block forever +# unless you are very careful. +# +# $wtr is left unbuffered. +# +# abort program if +# rdr or wtr are null +# pipe or fork or exec fails + +package open3; + +$fh = 'FHOPEN000'; # package static in case called more than once + +sub main'open3 { + local($kidpid); + local($dad_wtr, $dad_rdr, $dad_err, @cmd) = @_; + local($dup_wtr, $dup_rdr, $dup_err); + + $dad_wtr || die "open3: wtr should not be null"; + $dad_rdr || die "open3: rdr should not be null"; + $dad_err = $dad_rdr if ($dad_err eq ''); + + $dup_wtr = ($dad_wtr =~ s/^\>\&//); + $dup_rdr = ($dad_rdr =~ s/^\>\&//); + $dup_err = ($dad_err =~ s/^\>\&//); + + # force unqualified filehandles into callers' package + local($package) = caller; + $dad_wtr =~ s/^[^']+$/$package'$&/; + $dad_rdr =~ s/^[^']+$/$package'$&/; + $dad_err =~ s/^[^']+$/$package'$&/; + + local($kid_rdr) = ++$fh; + local($kid_wtr) = ++$fh; + local($kid_err) = ++$fh; + + if (!$dup_wtr) { + pipe($kid_rdr, $dad_wtr) || die "open3: pipe 1 (stdin) failed: $!"; + } + if (!$dup_rdr) { + pipe($dad_rdr, $kid_wtr) || die "open3: pipe 2 (stdout) failed: $!"; + } + if ($dad_err ne $dad_rdr && !$dup_err) { + pipe($dad_err, $kid_err) || die "open3: pipe 3 (stderr) failed: $!"; + } + + if (($kidpid = fork) < 0) { + die "open2: fork failed: $!"; + } elsif ($kidpid == 0) { + if ($dup_wtr) { + open(STDIN, ">&$dad_wtr") if (fileno(STDIN) != fileno($dad_wtr)); + } else { + close($dad_wtr); + open(STDIN, ">&$kid_rdr"); + } + if ($dup_rdr) { + open(STDOUT, ">&$dad_rdr") if (fileno(STDOUT) != fileno($dad_rdr)); + } else { + close($dad_rdr); + open(STDOUT, ">&$kid_wtr"); + } + if ($dad_rdr ne $dad_err) { + if ($dup_err) { + open(STDERR, ">&$dad_err") + if (fileno(STDERR) != fileno($dad_err)); + } else { + close($dad_err); + open(STDERR, ">&$kid_err"); + } + } else { + open(STDERR, ">&STDOUT") if (fileno(STDERR) != fileno(STDOUT)); + } + exec @cmd; + + local($")=(" "); + die "open2: exec of @cmd failed"; + } + + close $kid_rdr; close $kid_wtr; close $kid_err; + if ($dup_wtr) { + close($dad_wtr); + } + + select((select($dad_wtr), $| = 1)[0]); # unbuffer pipe + $kidpid; +} +1; # so require is happy |