treewide: "require" + "use" cleanup and docs

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

diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index 6493ad387cdbcb915ca71fcbdc325f0ce673f768..1c74a5964aa59235d51eaa6af7bbb9b37fecb4eb 100644 (file)
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -15,7 +15,6 @@ use strict;
 use warnings;
 use base qw(Exporter);
 use Symbol qw(gensym);
-use IO::Handle;
 use PublicInbox::ProcessPipe;
 our @EXPORT_OK = qw/which spawn popen_rd/;
 sub RLIMITS () { qw(RLIMIT_CPU RLIMIT_CORE RLIMIT_DATA) }
@@ -56,43 +55,22 @@ my $vfork_spawn = <<'VFORK_SPAWN';
        dst[real_len] = 0; \
 } while (0)
 
-static void *deconst(const char *s)
-{
-       union { const char *in; void *out; } u;
-       u.in = s;
-       return u.out;
-}
-
 /* needs to be safe inside a vfork'ed process */
-static void xerr(const char *msg)
+static void exit_err(int *cerrnum)
 {
-       struct iovec iov[3];
-       const char *err = strerror(errno); /* should be safe in practice */
-
-       iov[0].iov_base = deconst(msg);
-       iov[0].iov_len = strlen(msg);
-       iov[1].iov_base = deconst(err);
-       iov[1].iov_len = strlen(err);
-       iov[2].iov_base = deconst("\n");
-       iov[2].iov_len = 1;
-       writev(2, iov, 3);
+       *cerrnum = errno;
        _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,
+                const char *cd)
 {
+       AV *redir = (AV *)SvRV(redirref);
        AV *cmd = (AV *)SvRV(cmdref);
        AV *env = (AV *)SvRV(envref);
        AV *rlim = (AV *)SvRV(rlimref);
@@ -100,7 +78,7 @@ int pi_fork_exec(int in, int out, int err,
        pid_t pid;
        char **argv, **envp;
        sigset_t set, old;
-       int ret, errnum;
+       int ret, perrnum, cerrnum = 0;
 
        AV2C_COPY(argv, cmd);
        AV2C_COPY(envp, env);
@@ -112,13 +90,20 @@ 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)
+                               exit_err(&cerrnum);
+               }
                for (sig = 1; sig < NSIG; sig++)
                        signal(sig, SIG_DFL); /* ignore errors on signals */
+               if (*cd && chdir(cd) < 0)
+                       exit_err(&cerrnum);
 
                max = av_len(rlim);
                for (i = 0; i < max; i += 3) {
@@ -130,7 +115,7 @@ int pi_fork_exec(int in, int out, int err,
                        rl.rlim_cur = SvIV(*soft);
                        rl.rlim_max = SvIV(*hard);
                        if (setrlimit(SvIV(*res), &rl) < 0)
-                               xerr("sertlimit");
+                               exit_err(&cerrnum);
                }
 
                /*
@@ -138,13 +123,19 @@ int pi_fork_exec(int in, int out, int err,
                 * to the group taking out a subprocess
                 */
                execve(filename, argv, envp);
-               xerr("execve failed");
+               exit_err(&cerrnum);
        }
-       errnum = errno;
+       perrnum = errno;
        ret = sigprocmask(SIG_SETMASK, &old, NULL);
        assert(ret == 0 && "BUG calling sigprocmask to restore");
-       errno = errnum;
-
+       if (cerrnum) {
+               if (pid > 0)
+                       waitpid(pid, NULL, 0);
+               pid = -1;
+               errno = cerrnum;
+       } else if (perrnum) {
+               errno = perrnum;
+       }
        return (int)pid;
 }
 VFORK_SPAWN
@@ -172,8 +163,7 @@ if (defined $vfork_spawn) {
 
 unless (defined $vfork_spawn) {
        require PublicInbox::SpawnPP;
-       no warnings 'once';
-       *pi_fork_exec = *PublicInbox::SpawnPP::pi_fork_exec
+       *pi_fork_exec = \&PublicInbox::SpawnPP::pi_fork_exec
 }
 
 sub which ($) {
@@ -197,9 +187,16 @@ sub spawn ($;$$) {
        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 $l (RLIMITS()) {
@@ -211,7 +208,8 @@ sub spawn ($;$$) {
                }
                push @$rlim, $r, @$v;
        }
-       my $pid = pi_fork_exec($in, $out, $err, $f, $cmd, \@env, $rlim);
+       my $cd = $opts->{'-C'} // ''; # undef => NULL mapping doesn't work?
+       my $pid = pi_fork_exec($redir, $f, $cmd, \@env, $rlim, $cd);
        $pid < 0 ? undef : $pid;
 }