/* This is called from a signal handler */
void job_handle_signal ( int signal, siginfo_t *info, void *con )
{
int status;
pid_t pid;
int errno_old = errno;
got_signal = 1;
// write( 2, "got signal\n", 11 );
while(1)
{
switch(pid=waitpid( -1,&status,WUNTRACED|WNOHANG ))
{
case 0:
case -1:
{
errno=errno_old;
return;
}
default:
handle_child_status( pid, status );
break;
}
}
kill( 0, SIGIO );
errno=errno_old;
}
/* wait for a ptraced child to get a certain signal */
static int waitpid_thread( struct thread *thread, int signal )
{
int res, status;
start_watchdog();
for (;;)
{
if ((res = waitpid( get_ptrace_pid(thread), &status, WUNTRACED | __WALL )) == -1)
{
if (errno == EINTR)
{
if (!watchdog_triggered()) continue;
if (debug_level) fprintf( stderr, "%04x: *watchdog* waitpid aborted\n", thread->id );
}
else if (errno == ECHILD) /* must have died */
{
thread->unix_pid = -1;
thread->unix_tid = -1;
}
else perror( "waitpid" );
stop_watchdog();
return 0;
}
res = handle_child_status( thread, res, status, signal );
if (!res || res == signal) break;
}
stop_watchdog();
return (thread->unix_pid != -1);
}
/* If we have received a SIGCHLD signal, process any children. If await is false, this returns immediately if no SIGCHLD has been received. If await is true, this waits for one. Returns true if something was processed. This returns the number of children processed, or -1 on error. */
static int process_mark_finished_children(bool wants_await)
{
ASSERT_IS_MAIN_THREAD();
/* A static value tracking the SIGCHLD gen count at the time we last processed it. When this is different from s_sigchld_generation_count, it indicates there may be unreaped processes. There may not be if we reaped them via the other waitpid path. This is only ever modified from the main thread, and not from a signal handler. */
static process_generation_count_t s_last_processed_sigchld_generation_count = 0;
int processed_count = 0;
bool got_error = false;
/* The critical read. This fetches a value which is only written in the signal handler. This needs to be an atomic read (we'd use sig_atomic_t, if we knew that were unsigned - fortunately aligned unsigned int is atomic on pretty much any modern chip.) It also needs to occur before we start reaping, since the signal handler can be invoked at any point. */
const process_generation_count_t local_count = s_sigchld_generation_count;
/* Determine whether we have children to process. Note that we can't reliably use the difference because a single SIGCHLD may be delivered for multiple children - see #1768. Also if we are awaiting, we always process. */
bool wants_waitpid = wants_await || local_count != s_last_processed_sigchld_generation_count;
if (wants_waitpid)
{
for (;;)
{
/* Call waitpid until we get 0/ECHILD. If we wait, it's only on the first iteration. So we want to set NOHANG (don't wait) unless wants_await is true and this is the first iteration. */
int options = WUNTRACED;
if (! (wants_await && processed_count == 0))
{
options |= WNOHANG;
}
int status = -1;
pid_t pid = waitpid(-1, &status, options);
if (pid > 0)
{
/* We got a valid pid */
handle_child_status(pid, status);
processed_count += 1;
}
else if (pid == 0)
{
/* No ready-and-waiting children, we're done */
break;
}
else
{
/* This indicates an error. One likely failure is ECHILD (no children), which we break on, and is not considered an error. The other likely failure is EINTR, which means we got a signal, which is considered an error. */
got_error = (errno != ECHILD);
break;
}
}
}
if (got_error)
{
return -1;
}
else
{
s_last_processed_sigchld_generation_count = local_count;
return processed_count;
}
}
pid_t proc_wait_any() {
int pid_status;
pid_t pid = waitpid(-1, &pid_status, WUNTRACED);
if (pid == -1) return -1;
handle_child_status(pid, pid_status);
process_clean_after_marking(is_interactive);
return pid;
}
/* handle a SIGCHLD signal */
void sigchld_callback(void)
{
int pid, status;
for (;;)
{
if (!(pid = waitpid( -1, &status, WUNTRACED | WNOHANG | __WALL ))) break;
if (pid != -1)
{
struct thread *thread = get_thread_from_tid( pid );
if (!thread) thread = get_thread_from_pid( pid );
handle_child_status( thread, pid, status, -1 );
}
else break;
}
}
void job_continue (job_t *j, int 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. */
int ok;
signal_block();
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) {
// 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);
}
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 ))
{
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 circuted 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;
}
}
}
