X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FSpawn.pm;h=1ee40503c33f0b014bb6814295d890e3335133e2;hb=af0b0fb7a454470a32c452119d0392e0dedb3fe1;hp=72cd6c3cc4fce032bb8ce36b025854dbeb5b67b4;hpb=e6a02743e6411d6e70e4b72e749694445f9ff6db;p=public-inbox.git diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm index 72cd6c3c..1ee40503 100644 --- a/lib/PublicInbox/Spawn.pm +++ b/lib/PublicInbox/Spawn.pm @@ -1,107 +1,212 @@ -# Copyright (C) 2016 all contributors +# Copyright (C) 2016-2021 all contributors # License: AGPL-3.0+ # # This allows vfork to be used for spawning subprocesses if -# PERL_INLINE_DIRECTORY is explicitly defined in the environment. +# ~/.cache/public-inbox/inline-c is writable or if PERL_INLINE_DIRECTORY +# is explicitly defined in the environment (and writable). # 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. +# +# There'll probably be more OS-level C stuff here, down the line. +# We don't want too many DSOs: https://udrepper.livejournal.com/8790.html package PublicInbox::Spawn; use strict; -use warnings; -use base qw(Exporter); +use parent qw(Exporter); use Symbol qw(gensym); use PublicInbox::ProcessPipe; -our @EXPORT_OK = qw/which spawn popen_rd/; +our @EXPORT_OK = qw(which spawn popen_rd run_die nodatacow_dir); +our @RLIMITS = qw(RLIMIT_CPU RLIMIT_CORE RLIMIT_DATA); my $vfork_spawn = <<'VFORK_SPAWN'; #include -#include +#include +#include #include -#include - -#define AV_ALLOCA(av, max) alloca((max = (av_len((av)) + 1)) * sizeof(char *)) +#include +#include -static void av2c_copy(char **dst, AV *src, I32 max) -{ - I32 i; +/* some platforms need alloca.h, but some don't */ +#if defined(__GNUC__) && !defined(alloca) +# define alloca(sz) __builtin_alloca(sz) +#endif - for (i = 0; i < max; i++) { - SV **sv = av_fetch(src, i, 0); - dst[i] = sv ? SvPV_nolen(*sv) : 0; - } - dst[max] = 0; -} +#include +#include -static void *deconst(const char *s) -{ - union { const char *in; void *out; } u; - u.in = s; - return u.out; -} +/* + * From the av_len apidoc: + * Note that, unlike what the name implies, it returns + * the highest index in the array, so to get the size of + * the array you need to use "av_len(av) + 1". + * This is unlike "sv_len", which returns what you would expect. + */ +#define AV2C_COPY(dst, src) do { \ + I32 i; \ + I32 top_index = av_len(src); \ + I32 real_len = top_index + 1; \ + I32 capa = real_len + 1; \ + dst = alloca(capa * sizeof(char *)); \ + for (i = 0; i < real_len; i++) { \ + SV **sv = av_fetch(src, i, 0); \ + dst[i] = SvPV_nolen(*sv); \ + } \ + dst[real_len] = 0; \ +} while (0) /* 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 public_inbox_fork_exec(int in, int out, int err, - SV *file, SV *cmdref, SV *envref) +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); const char *filename = SvPV_nolen(file); pid_t pid; char **argv, **envp; - I32 max; + sigset_t set, old, cset; + int ret, perrnum, cerrnum = 0; - argv = AV_ALLOCA(cmd, max); - av2c_copy(argv, cmd, max); - - envp = AV_ALLOCA(env, max); - av2c_copy(envp, env, max); + AV2C_COPY(argv, cmd); + AV2C_COPY(envp, env); + ret = sigfillset(&set); + assert(ret == 0 && "BUG calling sigfillset"); + ret = sigprocmask(SIG_SETMASK, &set, &old); + assert(ret == 0 && "BUG calling sigprocmask to block"); + ret = sigemptyset(&cset); + assert(ret == 0 && "BUG calling sigemptyset"); + ret = sigaddset(&cset, SIGCHLD); + assert(ret == 0 && "BUG calling sigaddset for SIGCHLD"); pid = vfork(); if (pid == 0) { - REDIR(in, 0); - REDIR(out, 1); - REDIR(err, 2); + int sig; + 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) { + struct rlimit rl; + SV **res = av_fetch(rlim, i, 0); + SV **soft = av_fetch(rlim, i + 1, 0); + SV **hard = av_fetch(rlim, i + 2, 0); + + rl.rlim_cur = SvIV(*soft); + rl.rlim_max = SvIV(*hard); + if (setrlimit(SvIV(*res), &rl) < 0) + exit_err(&cerrnum); + } + + /* + * don't bother unblocking other signals for now, just SIGCHLD. + * we don't want signals to the group taking out a subprocess + */ + (void)sigprocmask(SIG_UNBLOCK, &cset, NULL); execve(filename, argv, envp); - xerr("execve failed"); + exit_err(&cerrnum); + } + perrnum = errno; + ret = sigprocmask(SIG_SETMASK, &old, NULL); + assert(ret == 0 && "BUG calling sigprocmask to restore"); + if (cerrnum) { + if (pid > 0) + waitpid(pid, NULL, 0); + pid = -1; + errno = cerrnum; + } else if (perrnum) { + errno = perrnum; } - return (int)pid; } VFORK_SPAWN -my $inline_dir = $ENV{PERL_INLINE_DIRECTORY}; -$vfork_spawn = undef unless defined $inline_dir && -d $inline_dir && -w _; +# btrfs on Linux is copy-on-write (COW) by default. As of Linux 5.7, +# this still leads to fragmentation for SQLite and Xapian files where +# random I/O happens, so we disable COW just for SQLite files and Xapian +# directories. Disabling COW disables checksumming, so we only do this +# for regeneratable files, and not canonical git storage (git doesn't +# checksum refs, only data under $GIT_DIR/objects). +my $set_nodatacow = $^O eq 'linux' ? <<'SET_NODATACOW' : ''; +#include +#include +#include +#include +#include +#include +#include +#include + +void nodatacow_fd(int fd) +{ + struct statfs buf; + int val = 0; + + if (fstatfs(fd, &buf) < 0) { + fprintf(stderr, "fstatfs: %s\\n", strerror(errno)); + return; + } + + /* only btrfs is known to have this problem, so skip for non-btrfs */ + if (buf.f_type != BTRFS_SUPER_MAGIC) + return; + + if (ioctl(fd, FS_IOC_GETFLAGS, &val) < 0) { + fprintf(stderr, "FS_IOC_GET_FLAGS: %s\\n", strerror(errno)); + return; + } + val |= FS_NOCOW_FL; + if (ioctl(fd, FS_IOC_SETFLAGS, &val) < 0) + fprintf(stderr, "FS_IOC_SET_FLAGS: %s\\n", strerror(errno)); +} + +void nodatacow_dir(const char *dir) +{ + DIR *dh = opendir(dir); + int fd; + + if (!dh) croak("opendir(%s): %s", dir, strerror(errno)); + fd = dirfd(dh); + if (fd >= 0) + nodatacow_fd(fd); + /* ENOTSUP probably won't happen under Linux... */ + closedir(dh); +} +SET_NODATACOW + +my $inline_dir = $ENV{PERL_INLINE_DIRECTORY} //= ( + $ENV{XDG_CACHE_HOME} // + ( ($ENV{HOME} // '/nonexistent').'/.cache' ) + ).'/public-inbox/inline-c'; + +$set_nodatacow = $vfork_spawn = undef unless -d $inline_dir && -w _; if (defined $vfork_spawn) { # Inline 0.64 or later has locking in multi-process env, # but we support 0.5 on Debian wheezy @@ -110,25 +215,40 @@ 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 . $set_nodatacow'; my $err = $@; + my $ndc_err; + if ($err && $set_nodatacow) { # missing Linux kernel headers + $ndc_err = $err; + undef $set_nodatacow; + eval 'use Inline C => $vfork_spawn'; + } flock($fh, LOCK_UN) or die "LOCK_UN failed on $f: $!\n"; die $err if $err; + warn $ndc_err if $ndc_err; }; if ($@) { warn "Inline::C failed for vfork: $@\n"; - $vfork_spawn = undef; + $set_nodatacow = $vfork_spawn = undef; } } unless (defined $vfork_spawn) { require PublicInbox::SpawnPP; + *pi_fork_exec = \&PublicInbox::SpawnPP::pi_fork_exec +} +unless ($set_nodatacow) { + require PublicInbox::NDC_PP; no warnings 'once'; - *public_inbox_fork_exec = *PublicInbox::SpawnPP::public_inbox_fork_exec + *nodatacow_fd = \&PublicInbox::NDC_PP::nodatacow_fd; + *nodatacow_dir = \&PublicInbox::NDC_PP::nodatacow_dir; } +undef $set_nodatacow; +undef $vfork_spawn; sub which ($) { my ($file) = @_; + return $file if index($file, '/') >= 0; foreach my $p (split(':', $ENV{PATH})) { $p .= "/$file"; return $p if -x $p; @@ -143,44 +263,54 @@ sub spawn ($;$$) { my @env; $opts ||= {}; - my %env = $opts->{-env} ? () : %ENV; - if ($env) { - foreach my $k (keys %$env) { - my $v = $env->{$k}; - if (defined $v) { - $env{$k} = $v; - } else { - delete $env{$k}; - } - } - } + my %env = $env ? (%ENV, %$env) : %ENV; while (my ($k, $v) = each %env) { push @env, "$k=$v"; } - my $in = $opts->{0} || 0; - my $out = $opts->{1} || 1; - my $err = $opts->{2} || 2; - public_inbox_fork_exec($in, $out, $err, $f, $cmd, \@env); + my $redir = []; + for my $child_fd (0..2) { + my $parent_fd = $opts->{$child_fd}; + if (defined($parent_fd) && $parent_fd !~ /\A[0-9]+\z/) { + defined(my $fd = fileno($parent_fd)) or + die "$parent_fd not an IO GLOB? $!"; + $parent_fd = $fd; + } + $redir->[$child_fd] = $parent_fd // $child_fd; + } + my $rlim = []; + + foreach my $l (@RLIMITS) { + defined(my $v = $opts->{$l}) or next; + my $r = eval "require BSD::Resource; BSD::Resource::$l();"; + unless (defined $r) { + warn "$l undefined by BSD::Resource: $@\n"; + next; + } + push @$rlim, $r, @$v; + } + my $cd = $opts->{'-C'} // ''; # undef => NULL mapping doesn't work? + my $pid = pi_fork_exec($redir, $f, $cmd, \@env, $rlim, $cd); + die "fork_exec @$cmd failed: $!\n" unless $pid > 0; + $pid; } sub popen_rd { my ($cmd, $env, $opts) = @_; - unless (wantarray || defined $vfork_spawn || defined $env) { - open my $fh, '-|', @$cmd or - die('open `'.join(' ', @$cmd) . " pipe failed: $!\n"); - return $fh - } pipe(my ($r, $w)) or die "pipe: $!\n"; $opts ||= {}; - my $blocking = $opts->{Blocking}; - $r->blocking($blocking) if defined $blocking; $opts->{1} = fileno($w); my $pid = spawn($cmd, $env, $opts); - close $w; return ($r, $pid) if wantarray; my $ret = gensym; tie *$ret, 'PublicInbox::ProcessPipe', $pid, $r; $ret; } +sub run_die ($;$$) { + my ($cmd, $env, $rdr) = @_; + my $pid = spawn($cmd, $env, $rdr); + waitpid($pid, 0) == $pid or die "@$cmd did not finish"; + $? == 0 or die "@$cmd failed: \$?=$?\n"; +} + 1;