void job_continue(job_t *j, bool cont) {
// Put job first in the job list.
job_promote(j);
j->set_flag(JOB_NOTIFIED, false);
CHECK_BLOCK();
debug(4, L"%ls job %d, gid %d (%ls), %ls, %ls", cont ? L"Continue" : L"Start", j->job_id,
j->pgid, j->command_wcstr(), job_is_completed(j) ? L"COMPLETED" : L"UNCOMPLETED",
is_interactive ? L"INTERACTIVE" : L"NON-INTERACTIVE");
if (!job_is_completed(j)) {
if (j->get_flag(JOB_TERMINAL) && j->get_flag(JOB_FOREGROUND)) {
// Put the job into the foreground. Hack: ensure that stdin is marked as blocking first
// (issue #176).
make_fd_blocking(STDIN_FILENO);
if (!terminal_give_to_job(j, cont)) return;
}
// Send the job a continue signal, if necessary.
if (cont) {
for (process_ptr_t &p : j->processes) p->stopped = false;
if (j->get_flag(JOB_CONTROL)) {
if (killpg(j->pgid, SIGCONT)) {
wperror(L"killpg (SIGCONT)");
return;
}
} else {
for (const process_ptr_t &p : j->processes) {
if (kill(p->pid, SIGCONT) < 0) {
wperror(L"kill (SIGCONT)");
return;
}
}
}
}
if (j->get_flag(JOB_FOREGROUND)) {
// Look for finished processes first, to avoid select() if it's already done.
process_mark_finished_children(false);
// Wait for job to report.
while (!reader_exit_forced() && !job_is_stopped(j) && !job_is_completed(j)) {
// debug( 1, L"select_try()" );
switch (select_try(j)) {
case 1: {
read_try(j);
process_mark_finished_children(false);
break;
}
case 0: {
// No FDs are ready. Look for finished processes.
process_mark_finished_children(false);
break;
}
case -1: {
// If there is no funky IO magic, we can use waitpid instead of handling
// child deaths through signals. This gives a rather large speed boost (A
// factor 3 startup time improvement on my 300 MHz machine) on short-lived
// jobs.
//
// This will return early if we get a signal, like SIGHUP.
process_mark_finished_children(true);
break;
}
default: {
DIE("unexpected return value from select_try()");
break;
}
}
}
}
}
if (j->get_flag(JOB_FOREGROUND)) {
if (job_is_completed(j)) {
// It's possible that the job will produce output and exit before we've even read from
// it.
//
// We'll eventually read the output, but it may be after we've executed subsequent calls
// This is why my prompt colors kept getting screwed up - the builtin echo calls
// were sometimes having their output combined with the set_color calls in the wrong
// order!
read_try(j);
const std::unique_ptr<process_t> &p = j->processes.back();
// Mark process status only if we are in the foreground and the last process in a pipe,
// and it is not a short circuited builtin.
if ((WIFEXITED(p->status) || WIFSIGNALED(p->status)) && p->pid) {
int status = proc_format_status(p->status);
// fwprintf(stdout, L"setting status %d for %ls\n", job_get_flag( j, JOB_NEGATE
// )?!status:status, j->command);
proc_set_last_status(j->get_flag(JOB_NEGATE) ? !status : status);
}
}
// Put the shell back in the foreground.
if (j->get_flag(JOB_TERMINAL) && j->get_flag(JOB_FOREGROUND)) {
terminal_return_from_job(j);
}
}
}
void job_continue(job_t *j, bool cont)
{
/*
Put job first in the job list
*/
job_promote(j);
job_set_flag(j, JOB_NOTIFIED, 0);
CHECK_BLOCK();
debug(4,
L"Continue job %d, gid %d (%ls), %ls, %ls",
j->job_id,
j->pgid,
j->command_wcstr(),
job_is_completed(j)?L"COMPLETED":L"UNCOMPLETED",
is_interactive?L"INTERACTIVE":L"NON-INTERACTIVE");
if (!job_is_completed(j))
{
if (job_get_flag(j, JOB_TERMINAL) && job_get_flag(j, JOB_FOREGROUND))
{
/* Put the job into the foreground. Hack: ensure that stdin is marked as blocking first (#176). */
make_fd_blocking(STDIN_FILENO);
signal_block();
bool ok = terminal_give_to_job(j, cont);
signal_unblock();
if (!ok)
return;
}
/*
Send the job a continue signal, if necessary.
*/
if (cont)
{
process_t *p;
for (p=j->first_process; p; p=p->next)
p->stopped=0;
if (job_get_flag(j, JOB_CONTROL))
{
if (killpg(j->pgid, SIGCONT))
{
wperror(L"killpg (SIGCONT)");
return;
}
}
else
{
for (p=j->first_process; p; p=p->next)
{
if (kill(p->pid, SIGCONT) < 0)
{
wperror(L"kill (SIGCONT)");
return;
}
}
}
}
if (job_get_flag(j, JOB_FOREGROUND))
{
int quit = 0;
/*
Wait for job to report. Looks a bit ugly because it has to
handle the possibility that a signal is dispatched while
running job_is_stopped().
*/
while (!quit)
{
do
{
got_signal = 0;
quit = job_is_stopped(j) || job_is_completed(j);
}
while (got_signal && !quit);
if (!quit)
{
// debug( 1, L"select_try()" );
switch (select_try(j))
{
case 1:
{
read_try(j);
break;
}
case -1:
{
/*
If there is no funky IO magic, we can use
waitpid instead of handling child deaths
through signals. This gives a rather large
speed boost (A factor 3 startup time
improvement on my 300 MHz machine) on
short-lived jobs.
*/
int status;
pid_t pid = waitpid(-1, &status, WUNTRACED);
if (pid > 0)
{
handle_child_status(pid, status);
}
else
{
/*
This probably means we got a
signal. A signal might mean that the
terminal emulator sent us a hup
signal to tell is to close. If so,
we should exit.
*/
if (reader_exit_forced())
{
quit = 1;
}
}
break;
}
}
}
}
}
}
if (job_get_flag(j, JOB_FOREGROUND))
{
if (job_is_completed(j))
{
// It's possible that the job will produce output and exit before we've even read from it.
// We'll eventually read the output, but it may be after we've executed subsequent calls
// This is why my prompt colors kept getting screwed up - the builtin echo calls
// were sometimes having their output combined with the set_color calls in the wrong order!
read_try(j);
process_t *p = j->first_process;
while (p->next)
p = p->next;
if (WIFEXITED(p->status) || WIFSIGNALED(p->status))
{
/*
Mark process status only if we are in the foreground
and the last process in a pipe, and it is not a short circuited builtin
*/
if (p->pid)
{
int status = proc_format_status(p->status);
//wprintf(L"setting status %d for %ls\n", job_get_flag( j, JOB_NEGATE )?!status:status, j->command);
proc_set_last_status(job_get_flag(j, JOB_NEGATE)?!status:status);
}
}
}
/* Put the shell back in the foreground. */
if (job_get_flag(j, JOB_TERMINAL) && job_get_flag(j, JOB_FOREGROUND))
{
int ok;
signal_block();
ok = terminal_return_from_job(j);
signal_unblock();
if (!ok)
return;
}
}
}
/// Executes an external command.
/// \return true on success, false if there is an exec error.
static bool exec_external_command(job_t *j, process_t *p, const io_chain_t &proc_io_chain) {
assert(p->type == EXTERNAL && "Process is not external");
// Get argv and envv before we fork.
null_terminated_array_t<char> argv_array;
convert_wide_array_to_narrow(p->get_argv_array(), &argv_array);
// Ensure that stdin is blocking before we hand it off (see issue #176). It's a
// little strange that we only do this with stdin and not with stdout or stderr.
// However in practice, setting or clearing O_NONBLOCK on stdin also sets it for the
// other two fds, presumably because they refer to the same underlying file
// (/dev/tty?).
make_fd_blocking(STDIN_FILENO);
const char *const *argv = argv_array.get();
const char *const *envv = env_export_arr();
std::string actual_cmd_str = wcs2string(p->actual_cmd);
const char *actual_cmd = actual_cmd_str.c_str();
const wchar_t *file = reader_current_filename();
#if FISH_USE_POSIX_SPAWN
// Prefer to use posix_spawn, since it's faster on some systems like OS X.
bool use_posix_spawn = g_use_posix_spawn && can_use_posix_spawn_for_job(j, p);
if (use_posix_spawn) {
g_fork_count++; // spawn counts as a fork+exec
// Create posix spawn attributes and actions.
pid_t pid = 0;
posix_spawnattr_t attr = posix_spawnattr_t();
posix_spawn_file_actions_t actions = posix_spawn_file_actions_t();
bool made_it = fork_actions_make_spawn_properties(&attr, &actions, j, p, proc_io_chain);
if (made_it) {
// We successfully made the attributes and actions; actually call
// posix_spawn.
int spawn_ret =
posix_spawn(&pid, actual_cmd, &actions, &attr, const_cast<char *const *>(argv),
const_cast<char *const *>(envv));
// This usleep can be used to test for various race conditions
// (https://github.com/fish-shell/fish-shell/issues/360).
// usleep(10000);
if (spawn_ret != 0) {
safe_report_exec_error(spawn_ret, actual_cmd, argv, envv);
// Make sure our pid isn't set.
pid = 0;
}
// Clean up our actions.
posix_spawn_file_actions_destroy(&actions);
posix_spawnattr_destroy(&attr);
}
// A 0 pid means we failed to posix_spawn. Since we have no pid, we'll never get
// told when it's exited, so we have to mark the process as failed.
debug(4, L"Fork #%d, pid %d: spawn external command '%s' from '%ls'", g_fork_count, pid,
actual_cmd, file ? file : L"<no file>");
if (pid == 0) {
job_mark_process_as_failed(j, p);
return false;
}
// these are all things do_fork() takes care of normally (for forked processes):
p->pid = pid;
on_process_created(j, p->pid);
// We explicitly don't call set_child_group() for spawned processes because that
// a) isn't necessary, and b) causes issues like fish-shell/fish-shell#4715
#if defined(__GLIBC__)
// Unfortunately, using posix_spawn() is not the panacea it would appear to be,
// glibc has a penchant for using fork() instead of vfork() when posix_spawn() is
// called, meaning that atomicity is not guaranteed and we can get here before the
// child group has been set. See discussion here:
// https://github.com/Microsoft/WSL/issues/2997 And confirmation that this persists
// past glibc 2.24+ here: https://github.com/fish-shell/fish-shell/issues/4715
if (j->get_flag(job_flag_t::JOB_CONTROL) && getpgid(p->pid) != j->pgid) {
set_child_group(j, p->pid);
}
#else
// In do_fork, the pid of the child process is used as the group leader if j->pgid
// invalid, posix_spawn assigned the new group a pgid equal to its own id if
// j->pgid was invalid, so this is what we do instead of calling set_child_group
if (j->pgid == INVALID_PID) {
j->pgid = pid;
}
#endif
maybe_assign_terminal(j);
} else
#endif
{
if (!fork_child_for_process(j, p, proc_io_chain, false, "external command",
[&] { safe_launch_process(p, actual_cmd, argv, envv); })) {
return false;
}
}
return true;
}
