spawn: allow passing GLOB handles for redirects

We can save callers the trouble of {-hold} and {-dev_null}
refs as well as the trouble of calling fileno().

1 files changed, 24 insertions, 18 deletions

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index c64812dd..6d42d5bc 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -79,20 +79,14 @@ static void xerr(const char *msg)
         _exit(1);
 }
 
-#define REDIR(var,fd) do { \
-        if (var != fd && dup2(var, fd) < 0) \
-                xerr("error redirecting std"#var ": "); \
-} while (0)
-
 /*
- * unstable internal API.  This was easy to implement but does not
- * support arbitrary redirects.  It'll be updated depending on
+ * unstable internal API.  It'll be updated depending on
  * whatever we'll need in the future.
  * Be sure to update PublicInbox::SpawnPP if this changes
  */
-int pi_fork_exec(int in, int out, int err,
-                        SV *file, SV *cmdref, SV *envref, SV *rlimref)
+int pi_fork_exec(SV *redirref, SV *file, SV *cmdref, SV *envref, SV *rlimref)
 {
+        AV *redir = (AV *)SvRV(redirref);
         AV *cmd = (AV *)SvRV(cmdref);
         AV *env = (AV *)SvRV(envref);
         AV *rlim = (AV *)SvRV(rlimref);
@@ -112,11 +106,16 @@ int pi_fork_exec(int in, int out, int err,
         pid = vfork();
         if (pid == 0) {
                 int sig;
-                I32 i, max;
-
-                REDIR(in, 0);
-                REDIR(out, 1);
-                REDIR(err, 2);
+                I32 i, child_fd, max = av_len(redir);
+
+                for (child_fd = 0; child_fd <= max; child_fd++) {
+                        SV **parent = av_fetch(redir, child_fd, 0);
+                        int parent_fd = SvIV(*parent);
+                        if (parent_fd == child_fd)
+                                continue;
+                        if (dup2(parent_fd, child_fd) < 0)
+                                xerr("dup2");
+                }
                 for (sig = 1; sig < NSIG; sig++)
                         signal(sig, SIG_DFL); /* ignore errors on signals */
 
@@ -196,9 +195,16 @@ sub spawn ($;$$) {
         while (my ($k, $v) = each %env) {
                 push @env, "$k=$v";
         }
-        my $in = $opts->{0} || 0;
-        my $out = $opts->{1} || 1;
-        my $err = $opts->{2} || 2;
+        my $redir = [];
+        for my $child_fd (0..2) {
+                my $parent_fd = $opts->{$child_fd};
+                if (defined($parent_fd) && $parent_fd !~ /\A[0-9]+\z/) {
+                        defined(my $fd = fileno($parent_fd)) or
+                                        die "$parent_fd not an IO GLOB? $!";
+                        $parent_fd = $fd;
+                }
+                $redir->[$child_fd] = $parent_fd // $child_fd;
+        }
         my $rlim = [];
 
         foreach my $l (RLIMITS()) {
@@ -210,7 +216,7 @@ sub spawn ($;$$) {
                 }
                 push @$rlim, $r, @$v;
         }
-        my $pid = pi_fork_exec($in, $out, $err, $f, $cmd, \@env, $rlim);
+        my $pid = pi_fork_exec($redir, $f, $cmd, \@env, $rlim);
         $pid < 0 ? undef : $pid;
 }