www: use WwwStream for dumping thread and search views

[public-inbox.git] / lib / PublicInbox / Spawn.pm

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index aa8d81b36de4832303fe1b923b26b092cd4dff64..41b08a33e9b2aa512d5eff91109c791569f5b849 100644 (file)
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -1,16 +1,31 @@
 # Copyright (C) 2016 all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+#
+# This allows vfork to be used for spawning subprocesses if
+# PERL_INLINE_DIRECTORY is explicitly defined in the environment.
+# Under Linux, vfork can make a big difference in spawning performance
+# as process size increases (fork still needs to mark pages for CoW use).
+# Currently, we only use this for code intended for long running
+# daemons (inside the PSGI code (-httpd) and -nntpd).  The short-lived
+# scripts (-mda, -index, -learn, -init) either use IPC::run or standard
+# Perl routines.
+
 package PublicInbox::Spawn;
 use strict;
 use warnings;
 use base qw(Exporter);
-our @EXPORT_OK = qw/which spawn/;
+use Symbol qw(gensym);
+use IO::Handle;
+use PublicInbox::ProcessPipe;
+our @EXPORT_OK = qw/which spawn popen_rd/;
 
 my $vfork_spawn = <<'VFORK_SPAWN';
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <unistd.h>
 #include <alloca.h>
+#include <signal.h>
+#include <assert.h>
 
 #define AV_ALLOCA(av, max) alloca((max = (av_len((av)) + 1)) * sizeof(char *))
 
@@ -68,6 +83,8 @@ int public_inbox_fork_exec(int in, int out, int err,
        pid_t pid;
        char **argv, **envp;
        I32 max;
+       sigset_t set, old;
+       int ret, errnum;
 
        argv = AV_ALLOCA(cmd, max);
        av2c_copy(argv, cmd, max);
@@ -75,14 +92,30 @@ int public_inbox_fork_exec(int in, int out, int err,
        envp = AV_ALLOCA(env, max);
        av2c_copy(envp, env, max);
 
+       ret = sigfillset(&set);
+       assert(ret == 0 && "BUG calling sigfillset");
+       ret = sigprocmask(SIG_SETMASK, &set, &old);
+       assert(ret == 0 && "BUG calling sigprocmask to block");
        pid = vfork();
        if (pid == 0) {
+               int sig;
+
                REDIR(in, 0);
                REDIR(out, 1);
                REDIR(err, 2);
+               for (sig = 1; sig < NSIG; sig++)
+                       signal(sig, SIG_DFL); /* ignore errors on signals */
+               /*
+                * don't bother unblocking, we don't want signals
+                * to the group taking out a subprocess
+                */
                execve(filename, argv, envp);
                xerr("execve failed");
        }
+       errnum = errno;
+       ret = sigprocmask(SIG_SETMASK, &old, NULL);
+       assert(ret == 0 && "BUG calling sigprocmask to restore");
+       errno = errnum;
 
        return (int)pid;
 }
@@ -98,8 +131,10 @@ if (defined $vfork_spawn) {
                my $f = "$inline_dir/.public-inbox.lock";
                open my $fh, '>', $f or die "failed to open $f: $!\n";
                flock($fh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n";
-               eval 'use Inline C => $vfork_spawn';
+               eval 'use Inline C => $vfork_spawn'; #, BUILD_NOISY => 1';
+               my $err = $@;
                flock($fh, LOCK_UN) or die "LOCK_UN failed on $f: $!\n";
+               die $err if $err;
        };
        if ($@) {
                warn "Inline::C failed for vfork: $@\n";
@@ -113,6 +148,7 @@ unless (defined $vfork_spawn) {
        *public_inbox_fork_exec = *PublicInbox::SpawnPP::public_inbox_fork_exec
 }
 
+# n.b. we never use absolute paths with this
 sub which ($) {
        my ($file) = @_;
        foreach my $p (split(':', $ENV{PATH})) {
@@ -146,7 +182,23 @@ sub spawn ($;$$) {
        my $in = $opts->{0} || 0;
        my $out = $opts->{1} || 1;
        my $err = $opts->{2} || 2;
-       public_inbox_fork_exec($in, $out, $err, $f, $cmd, \@env);
+       my $pid = public_inbox_fork_exec($in, $out, $err, $f, $cmd, \@env);
+       $pid < 0 ? undef : $pid;
+}
+
+sub popen_rd {
+       my ($cmd, $env, $opts) = @_;
+       pipe(my ($r, $w)) or die "pipe: $!\n";
+       $opts ||= {};
+       my $blocking = $opts->{Blocking};
+       IO::Handle::blocking($r, $blocking) if defined $blocking;
+       $opts->{1} = fileno($w);
+       my $pid = spawn($cmd, $env, $opts);
+       return unless defined $pid;
+       return ($r, $pid) if wantarray;
+       my $ret = gensym;
+       tie *$ret, 'PublicInbox::ProcessPipe', $pid, $r;
+       $ret;
 }
 
 1;