} while (0)
/* needs to be safe inside a vfork'ed process */
-static void exit_err(int *cerrnum)
+static void exit_err(const char *fn, volatile int *cerrnum)
{
*cerrnum = errno;
+ write(2, fn, strlen(fn));
_exit(1);
}
* Be sure to update PublicInbox::SpawnPP if this changes
*/
int pi_fork_exec(SV *redirref, SV *file, SV *cmdref, SV *envref, SV *rlimref,
- const char *cd)
+ const char *cd, int pgid)
{
AV *redir = (AV *)SvRV(redirref);
AV *cmd = (AV *)SvRV(cmdref);
const char *filename = SvPV_nolen(file);
pid_t pid;
char **argv, **envp;
- sigset_t set, old, cset;
- int ret, perrnum, cerrnum = 0;
+ sigset_t set, old;
+ int ret, perrnum;
+ volatile int cerrnum = 0; /* shared due to vfork */
+ int chld_is_member;
+ I32 max_fd = av_len(redir);
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");
+ if (sigfillset(&set)) return -1;
+ if (sigprocmask(SIG_SETMASK, &set, &old)) return -1;
+ chld_is_member = sigismember(&old, SIGCHLD);
+ if (chld_is_member < 0) return -1;
+ if (chld_is_member > 0)
+ sigdelset(&old, SIGCHLD);
+
pid = vfork();
if (pid == 0) {
int sig;
- I32 i, child_fd, max = av_len(redir);
+ I32 i, child_fd, max_rlim;
- for (child_fd = 0; child_fd <= max; child_fd++) {
+ for (child_fd = 0; child_fd <= max_fd; 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);
+ exit_err("dup2", &cerrnum);
}
+ if (pgid >= 0 && setpgid(0, pgid) < 0)
+ exit_err("setpgid", &cerrnum);
for (sig = 1; sig < NSIG; sig++)
signal(sig, SIG_DFL); /* ignore errors on signals */
if (*cd && chdir(cd) < 0)
- exit_err(&cerrnum);
+ exit_err("chdir", &cerrnum);
- max = av_len(rlim);
- for (i = 0; i < max; i += 3) {
+ max_rlim = av_len(rlim);
+ for (i = 0; i < max_rlim; i += 3) {
struct rlimit rl;
SV **res = av_fetch(rlim, i, 0);
SV **soft = av_fetch(rlim, i + 1, 0);
rl.rlim_cur = SvIV(*soft);
rl.rlim_max = SvIV(*hard);
if (setrlimit(SvIV(*res), &rl) < 0)
- exit_err(&cerrnum);
+ exit_err("setrlimit", &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);
+ (void)sigprocmask(SIG_SETMASK, &old, NULL);
execve(filename, argv, envp);
- exit_err(&cerrnum);
+ exit_err("execve", &cerrnum);
}
perrnum = errno;
+ if (chld_is_member > 0)
+ sigaddset(&old, SIGCHLD);
ret = sigprocmask(SIG_SETMASK, &old, NULL);
assert(ret == 0 && "BUG calling sigprocmask to restore");
if (cerrnum) {
+ int err_fd = STDERR_FILENO;
+ if (err_fd <= max_fd) {
+ SV **parent = av_fetch(redir, err_fd, 0);
+ err_fd = SvIV(*parent);
+ }
if (pid > 0)
waitpid(pid, NULL, 0);
pid = -1;
+ /* continue message started by exit_err in child */
+ dprintf(err_fd, ": %s\n", strerror(cerrnum));
errno = cerrnum;
} else if (perrnum) {
errno = perrnum;
my $f = which($cmd->[0]) // die "$cmd->[0]: command not found\n";
my @env;
$opts ||= {};
-
- my %env = $env ? (%ENV, %$env) : %ENV;
+ my %env = (%ENV, $env ? %$env : ());
while (my ($k, $v) = each %env) {
- push @env, "$k=$v";
+ push @env, "$k=$v" if defined($v);
}
my $redir = [];
for my $child_fd (0..2) {
push @$rlim, $r, @$v;
}
my $cd = $opts->{'-C'} // ''; # undef => NULL mapping doesn't work?
- my $pid = pi_fork_exec($redir, $f, $cmd, \@env, $rlim, $cd);
+ my $pgid = $opts->{pgid} // -1;
+ my $pid = pi_fork_exec($redir, $f, $cmd, \@env, $rlim, $cd, $pgid);
die "fork_exec @$cmd failed: $!\n" unless $pid > 0;
$pid;
}