ReceiveTempSMS
/
Sweden-Number
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Added a watchdog mechanism to break out of the wait4 call in case it 

didn't return properly (can happen at thread exit).
This commit is contained in:
Alexandre Julliard 2005-08-19 14:01:43 +00:00
parent b6d97d5654
commit 9d99a04880
3 changed files with 54 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
server/object.h
View File

@ -153,6 +153,9 @@ extern void close_registry(void);
/* signal functions */
extern void start_watchdog(void);
extern void stop_watchdog(void);
extern int watchdog_triggered(void);
extern void init_signals(void);
extern void close_signals(void);

43
server/ptrace.c
View File

@ -139,23 +139,30 @@ static int wait4_thread( struct thread *thread, int signal )
{
int res, status;
start_watchdog();
for (;;)
{
if ((res = wait4_wrapper( get_ptrace_pid(thread), &status, WUNTRACED, NULL )) == -1)
{
if (errno == EINTR) continue;
if (errno == ECHILD) /* must have died */
if (errno == EINTR)
{
if (!watchdog_triggered()) continue;
if (debug_level) fprintf( stderr, "%04x: *watchdog* wait4 aborted\n", thread->id );
}
else if (errno == ECHILD) /* must have died */
{
thread->unix_pid = -1;
thread->unix_tid = -1;
thread->attached = 0;
}
else perror( "wait4" );
stop_watchdog();
return 0;
}
res = handle_child_status( thread, res, status, signal );
if (!res || res == signal) break;
}
stop_watchdog();
return (thread->unix_pid != -1);
}
@ -190,21 +197,6 @@ int send_thread_signal( struct thread *thread, int sig )
return (ret != -1);
}
/* attach to a Unix thread */
static int attach_thread( struct thread *thread )
{
/* this may fail if the client is already being debugged */
if (!use_ptrace) return 0;
if (ptrace( PTRACE_ATTACH, get_ptrace_pid(thread), 0, 0 ) == -1)
{
if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1; /* thread got killed */
return 0;
}
if (debug_level) fprintf( stderr, "%04x: *attached*\n", thread->id );
thread->attached = 1;
return wait4_thread( thread, SIGSTOP );
}
/* detach from a Unix thread and kill it */
void detach_thread( struct thread *thread, int sig )
{
@ -264,10 +256,21 @@ int suspend_for_ptrace( struct thread *thread )
if (thread->attached)
{
if (!send_thread_signal( thread, SIGSTOP )) goto error;
if (!wait4_thread( thread, SIGSTOP )) goto error;
return 1;
}
if (attach_thread( thread )) return 1;
else
{
/* this may fail if the client is already being debugged */
if (!use_ptrace) goto error;
if (ptrace( PTRACE_ATTACH, get_ptrace_pid(thread), 0, 0 ) == -1)
{
if (errno == ESRCH) thread->unix_pid = thread->unix_tid = -1; /* thread got killed */
goto error;
}
if (debug_level) fprintf( stderr, "%04x: *attached*\n", thread->id );
thread->attached = 1;
}
if (wait4_thread( thread, SIGSTOP )) return 1;
resume_after_ptrace( thread );
error:
set_error( STATUS_ACCESS_DENIED );
return 0;

28
server/signal.c
View File

@ -88,6 +88,8 @@ static struct handler *handler_sigio;
static sigset_t blocked_sigset;
static int watchdog;
/* create a signal handler */
static struct handler *create_handler( signal_callback callback )
{
@ -199,6 +201,12 @@ static void do_sigint( int signum )
do_signal( handler_sigint );
}
/* SIGALRM handler */
static void do_sigalrm( int signum )
{
watchdog = 1;
}
/* SIGCHLD handler */
static void do_sigchld( int signum )
{
@ -214,6 +222,23 @@ static void do_sigio( int signum, siginfo_t *si, void *x )
}
#endif
void start_watchdog(void)
{
alarm( 3 );
watchdog = 0;
}
void stop_watchdog(void)
{
alarm( 0 );
watchdog = 0;
}
int watchdog_triggered(void)
{
return watchdog != 0;
}
void init_signals(void)
{
struct sigaction action;
@ -228,6 +253,7 @@ void init_signals(void)
sigaddset( &blocked_sigset, SIGCHLD );
sigaddset( &blocked_sigset, SIGHUP );
sigaddset( &blocked_sigset, SIGINT );
sigaddset( &blocked_sigset, SIGALRM );
sigaddset( &blocked_sigset, SIGIO );
sigaddset( &blocked_sigset, SIGQUIT );
sigaddset( &blocked_sigset, SIGTERM );
@ -246,6 +272,8 @@ void init_signals(void)
sigaction( SIGHUP, &action, NULL );
action.sa_handler = do_sigint;
sigaction( SIGINT, &action, NULL );
action.sa_handler = do_sigalrm;
sigaction( SIGALRM, &action, NULL );
action.sa_handler = do_sigterm;
sigaction( SIGQUIT, &action, NULL );
sigaction( SIGTERM, &action, NULL );