Commit | Line | Data |
ee0007ab |
1 | # &open2: tom christiansen, <tchrist@convex.com> |
2 | # |
3 | # usage: $pid = &open2('rdr', 'wtr', 'some cmd and args'); |
4 | # or $pid = &open2('rdr', 'wtr', 'some', 'cmd', 'and', 'args'); |
5 | # |
6 | # spawn the given $cmd and connect $rdr for |
7 | # reading and $wtr for writing. return pid |
8 | # of child, or 0 on failure. |
9 | # |
10 | # WARNING: this is dangerous, as you may block forever |
11 | # unless you are very careful. |
12 | # |
13 | # $wtr is left unbuffered. |
14 | # |
15 | # abort program if |
16 | # rdr or wtr are null |
17 | # pipe or fork or exec fails |
18 | |
19 | package open2; |
20 | $fh = 'FHOPEN000'; # package static in case called more than once |
21 | |
22 | sub main'open2 { |
23 | local($kidpid); |
24 | local($dad_rdr, $dad_wtr, @cmd) = @_; |
25 | |
26 | $dad_rdr ne '' || die "open2: rdr should not be null"; |
27 | $dad_wtr ne '' || die "open2: wtr should not be null"; |
28 | |
29 | # force unqualified filehandles into callers' package |
30 | local($package) = caller; |
31 | $dad_rdr =~ s/^[^']+$/$package'$&/; |
32 | $dad_wtr =~ s/^[^']+$/$package'$&/; |
33 | |
34 | local($kid_rdr) = ++$fh; |
35 | local($kid_wtr) = ++$fh; |
36 | |
37 | pipe($dad_rdr, $kid_wtr) || die "open2: pipe 1 failed: $!"; |
38 | pipe($kid_rdr, $dad_wtr) || die "open2: pipe 2 failed: $!"; |
39 | |
40 | if (($kidpid = fork) < 0) { |
41 | die "open2: fork failed: $!"; |
42 | } elsif ($kidpid == 0) { |
43 | close $dad_rdr; close $dad_wtr; |
44 | open(STDIN, "<&$kid_rdr"); |
45 | open(STDOUT, ">&$kid_wtr"); |
46 | warn "execing @cmd\n" if $debug; |
47 | exec @cmd; |
48 | die "open2: exec of @cmd failed"; |
49 | } |
50 | close $kid_rdr; close $kid_wtr; |
51 | select((select($dad_wtr), $| = 1)[0]); # unbuffer pipe |
52 | $kidpid; |
53 | } |
54 | 1; # so require is happy |