1 # Copyright (C) 2016-2018 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # This allows vfork to be used for spawning subprocesses if
5 # PERL_INLINE_DIRECTORY is explicitly defined in the environment.
6 # Under Linux, vfork can make a big difference in spawning performance
7 # as process size increases (fork still needs to mark pages for CoW use).
8 # Currently, we only use this for code intended for long running
9 # daemons (inside the PSGI code (-httpd) and -nntpd). The short-lived
10 # scripts (-mda, -index, -learn, -init) either use IPC::run or standard
13 package PublicInbox::Spawn;
16 use base qw(Exporter);
17 use Symbol qw(gensym);
19 use PublicInbox::ProcessPipe;
20 our @EXPORT_OK = qw/which spawn popen_rd/;
21 sub RLIMITS () { qw(RLIMIT_CPU RLIMIT_CORE RLIMIT_DATA) }
23 my $vfork_spawn = <<'VFORK_SPAWN';
24 #include <sys/types.h>
27 #include <sys/resource.h>
31 /* some platforms need alloca.h, but some don't */
32 #if defined(__GNUC__) && !defined(alloca)
33 # define alloca(sz) __builtin_alloca(sz)
40 * From the av_len apidoc:
41 * Note that, unlike what the name implies, it returns
42 * the highest index in the array, so to get the size of
43 * the array you need to use "av_len(av) + 1".
44 * This is unlike "sv_len", which returns what you would expect.
46 #define AV2C_COPY(dst, src) do { \
48 I32 top_index = av_len(src); \
49 I32 real_len = top_index + 1; \
50 I32 capa = real_len + 1; \
51 dst = alloca(capa * sizeof(char *)); \
52 for (i = 0; i < real_len; i++) { \
53 SV **sv = av_fetch(src, i, 0); \
54 dst[i] = SvPV_nolen(*sv); \
59 static void *deconst(const char *s)
61 union { const char *in; void *out; } u;
66 /* needs to be safe inside a vfork'ed process */
67 static void xerr(const char *msg)
70 const char *err = strerror(errno); /* should be safe in practice */
72 iov[0].iov_base = deconst(msg);
73 iov[0].iov_len = strlen(msg);
74 iov[1].iov_base = deconst(err);
75 iov[1].iov_len = strlen(err);
76 iov[2].iov_base = deconst("\n");
82 #define REDIR(var,fd) do { \
83 if (var != fd && dup2(var, fd) < 0) \
84 xerr("error redirecting std"#var ": "); \
88 * unstable internal API. This was easy to implement but does not
89 * support arbitrary redirects. It'll be updated depending on
90 * whatever we'll need in the future.
91 * Be sure to update PublicInbox::SpawnPP if this changes
93 int pi_fork_exec(int in, int out, int err,
94 SV *file, SV *cmdref, SV *envref, SV *rlimref)
96 AV *cmd = (AV *)SvRV(cmdref);
97 AV *env = (AV *)SvRV(envref);
98 AV *rlim = (AV *)SvRV(rlimref);
99 const char *filename = SvPV_nolen(file);
105 AV2C_COPY(argv, cmd);
106 AV2C_COPY(envp, env);
108 ret = sigfillset(&set);
109 assert(ret == 0 && "BUG calling sigfillset");
110 ret = sigprocmask(SIG_SETMASK, &set, &old);
111 assert(ret == 0 && "BUG calling sigprocmask to block");
120 for (sig = 1; sig < NSIG; sig++)
121 signal(sig, SIG_DFL); /* ignore errors on signals */
124 for (i = 0; i < max; i += 3) {
126 SV **res = av_fetch(rlim, i, 0);
127 SV **soft = av_fetch(rlim, i + 1, 0);
128 SV **hard = av_fetch(rlim, i + 2, 0);
130 rl.rlim_cur = SvIV(*soft);
131 rl.rlim_max = SvIV(*hard);
132 if (setrlimit(SvIV(*res), &rl) < 0)
137 * don't bother unblocking, we don't want signals
138 * to the group taking out a subprocess
140 execve(filename, argv, envp);
141 xerr("execve failed");
144 ret = sigprocmask(SIG_SETMASK, &old, NULL);
145 assert(ret == 0 && "BUG calling sigprocmask to restore");
152 my $inline_dir = $ENV{PERL_INLINE_DIRECTORY};
153 $vfork_spawn = undef unless defined $inline_dir && -d $inline_dir && -w _;
154 if (defined $vfork_spawn) {
155 # Inline 0.64 or later has locking in multi-process env,
156 # but we support 0.5 on Debian wheezy
157 use Fcntl qw(:flock);
159 my $f = "$inline_dir/.public-inbox.lock";
160 open my $fh, '>', $f or die "failed to open $f: $!\n";
161 flock($fh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n";
162 eval 'use Inline C => $vfork_spawn'; #, BUILD_NOISY => 1';
164 flock($fh, LOCK_UN) or die "LOCK_UN failed on $f: $!\n";
168 warn "Inline::C failed for vfork: $@\n";
169 $vfork_spawn = undef;
173 unless (defined $vfork_spawn) {
174 require PublicInbox::SpawnPP;
176 *pi_fork_exec = *PublicInbox::SpawnPP::pi_fork_exec
181 return $file if index($file, '/') == 0;
182 foreach my $p (split(':', $ENV{PATH})) {
190 my ($cmd, $env, $opts) = @_;
191 my $f = which($cmd->[0]);
192 defined $f or die "$cmd->[0]: command not found\n";
196 my %env = $opts->{-env} ? () : %ENV;
198 foreach my $k (keys %$env) {
207 while (my ($k, $v) = each %env) {
210 my $in = $opts->{0} || 0;
211 my $out = $opts->{1} || 1;
212 my $err = $opts->{2} || 2;
215 foreach my $l (RLIMITS()) {
216 defined(my $v = $opts->{$l}) or next;
217 my $r = eval "require BSD::Resource; BSD::Resource::$l();";
218 unless (defined $r) {
219 warn "$l undefined by BSD::Resource: $@\n";
222 push @$rlim, $r, @$v;
224 my $pid = pi_fork_exec($in, $out, $err, $f, $cmd, \@env, $rlim);
225 $pid < 0 ? undef : $pid;
229 my ($cmd, $env, $opts) = @_;
230 pipe(my ($r, $w)) or die "pipe: $!\n";
232 $opts->{1} = fileno($w);
233 my $pid = spawn($cmd, $env, $opts);
234 return unless defined $pid;
235 return ($r, $pid) if wantarray;
237 tie *$ret, 'PublicInbox::ProcessPipe', $pid, $r;