diff options
Diffstat (limited to 'nuttx/sched/sched_waitpid.c')
| -rw-r--r-- | nuttx/sched/sched_waitpid.c | 167 |
1 files changed, 103 insertions, 64 deletions
diff --git a/nuttx/sched/sched_waitpid.c b/nuttx/sched/sched_waitpid.c index fe3f7167d..0285c2673 100644 --- a/nuttx/sched/sched_waitpid.c +++ b/nuttx/sched/sched_waitpid.c @@ -47,6 +47,7 @@ #include <nuttx/sched.h> #include "os_internal.h" +#include "group_internal.h" #ifdef CONFIG_SCHED_WAITPID @@ -171,21 +172,17 @@ * * Assumptions: * - *****************************************************************************/ - -/*************************************************************************** - * NOTE: This is a partially functional, experimental version of waitpid() - * - * If there is no SIGCHLD signal supported (CONFIG_SCHED_HAVE_PARENT not - * defined), then waitpid() is still available, but does not obey the - * restriction that the pid be a child of the caller. + * Compatibility + * If there is no SIGCHLD signal supported (CONFIG_SCHED_HAVE_PARENT not + * defined), then waitpid() is still available, but does not obey the + * restriction that the pid be a child of the caller. * - ***************************************************************************/ + *****************************************************************************/ #ifndef CONFIG_SCHED_HAVE_PARENT pid_t waitpid(pid_t pid, int *stat_loc, int options) { - _TCB *tcb; + _TCB *ctcb; bool mystat; int err; int ret; @@ -208,8 +205,8 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) /* Get the TCB corresponding to this PID */ - tcb = sched_gettcb(pid); - if (!tcb) + ctcb = sched_gettcb(pid); + if (!ctcb) { err = ECHILD; goto errout_with_errno; @@ -221,15 +218,15 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) * others? */ - if (stat_loc != NULL && tcb->stat_loc == NULL) + if (stat_loc != NULL && ctcb->stat_loc == NULL) { - tcb->stat_loc = stat_loc; - mystat = true; + ctcb->stat_loc = stat_loc; + mystat = true; } /* Then wait for the task to exit */ - ret = sem_wait(&tcb->exitsem); + ret = sem_wait(&ctcb->exitsem); if (ret < 0) { /* Unlock pre-emption and return the ERROR (sem_wait has already set @@ -239,7 +236,7 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) if (mystat) { - tcb->stat_loc = NULL; + ctcb->stat_loc = NULL; } goto errout; @@ -274,8 +271,10 @@ errout: pid_t waitpid(pid_t pid, int *stat_loc, int options) { FAR _TCB *rtcb = (FAR _TCB *)g_readytorun.head; + FAR _TCB *ctcb; #ifdef CONFIG_SCHED_CHILD_STATUS FAR struct child_status_s *child; + bool retains; #endif FAR struct siginfo info; sigset_t sigset; @@ -303,27 +302,47 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) sched_lock(); - /* Verify that this task actually has children and that the the request - * TCB is actually a child of this task. + /* Verify that this task actually has children and that the requested PID + * is actually a child of this task. */ #ifdef CONFIG_SCHED_CHILD_STATUS - if (rtcb->children == NULL) - { - /* There are no children */ + /* Does this task retain child status? */ + retains = ((rtcb->group->tg_flags && GROUP_FLAG_NOCLDWAIT) == 0); + + if (rtcb->group->tg_children == NULL && retains) + { err = ECHILD; goto errout_with_errno; } else if (pid != (pid_t)-1) { - /* This specific pid is not a child */ + /* Get the TCB corresponding to this PID and make sure it is our child. */ - if (task_findchild(rtcb, pid) == NULL) + ctcb = sched_gettcb(pid); +#ifdef HAVE_GROUP_MEMBERS + if (!ctcb || ctcb->group->tg_pgid != rtcb->group->tg_gid) +#else + if (!ctcb || ctcb->ppid != rtcb->pid) +#endif { err = ECHILD; goto errout_with_errno; } + + /* Does this task retain child status? */ + + if (retains) + { + /* Check if this specific pid has allocated child status? */ + + if (group_findchild(rtcb->group, pid) == NULL) + { + err = ECHILD; + goto errout_with_errno; + } + } } #else if (rtcb->nchildren == 0) @@ -337,8 +356,12 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) { /* Get the TCB corresponding to this PID and make sure it is our child. */ - FAR _TCB *ctcb = sched_gettcb(pid); - if (!ctcb || ctcb->parent != rtcb->pid) + ctcb = sched_gettcb(pid); +#ifdef HAVE_GROUP_MEMBERS + if (!ctcb || ctcb->group->tg_pgid != rtcb->group->tg_gid) +#else + if (!ctcb || ctcb->ppid != rtcb->pid) +#endif { err = ECHILD; goto errout_with_errno; @@ -350,6 +373,7 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) for (;;) { +#ifdef CONFIG_SCHED_CHILD_STATUS /* Check if the task has already died. Signals are not queued in * NuttX. So a possibility is that the child has died and we * missed the death of child signal (we got some other signal @@ -362,39 +386,33 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) * chilren. */ -#ifdef CONFIG_SCHED_CHILD_STATUS - DEBUGASSERT(rtcb->children); - if (rtcb->children == NULL) -#else - if (rtcb->nchildren == 0) -#endif + DEBUGASSERT(!retains || rtcb->group->tg_children); + if (retains && (child = group_exitchild(rtcb->group)) != NULL) { - /* There were one or more children when we started so they - * must have exit'ed. There are just no bread crumbs left - * behind to tell us the PID(s) of the existed children. - * Reporting ECHLD is about all we can do in this case. + /* A child has exited. Apparently we missed the signal. + * Return the saved exit status. */ - err = ECHILD; - goto errout_with_errno; + /* The child has exited. Return the saved exit status */ + + *stat_loc = child->ch_status << 8; + + /* Discard the child entry and break out of the loop */ + + (void)group_removechild(rtcb->group, child->ch_pid); + group_freechild(child); + break; } } - else + + /* We are waiting for a specific PID. Does this task retain child status? */ + + else if (retains) { -#ifdef CONFIG_SCHED_CHILD_STATUS - /* We are waiting for a specific PID. Get the current status - * of the child task. - */ + /* Get the current status of the child task. */ - child = task_findchild(rtcb, pid); + child = group_findchild(rtcb->group, pid); DEBUGASSERT(child); - if (!child) - { - /* Yikes! The child status entry just disappeared! */ - - err = ECHILD; - goto errout_with_errno; - } /* Did the child exit? */ @@ -402,33 +420,54 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) { /* The child has exited. Return the saved exit status */ - *stat_loc = child->ch_status; + *stat_loc = child->ch_status << 8; /* Discard the child entry and break out of the loop */ - (void)task_removechild(rtcb, pid); - task_freechild(child); + (void)group_removechild(rtcb->group, pid); + group_freechild(child); + break; } -#else - /* We are waiting for a specific PID. We can use kill() with - * signal number 0 to determine if that task is still alive. + } + else + { + /* We can use kill() with signal number 0 to determine if that + * task is still alive. */ ret = kill(pid, 0); if (ret < 0) { - /* It is no longer running. We know that the child task was - * running okay when we started, so we must have lost the - * signal. In this case, we know that the task exit'ed, but - * we do not know its exit status. It would be better to - * reported ECHILD that bogus status. + /* It is no longer running. We know that the child task + * was running okay when we started, so we must have lost + * the signal. In this case, we know that the task exit'ed, + * but we do not know its exit status. It would be better + * to reported ECHILD than bogus status. */ err = ECHILD; goto errout_with_errno; } -#endif } +#else + /* Check if the task has already died. Signals are not queued in + * NuttX. So a possibility is that the child has died and we + * missed the death of child signal (we got some other signal + * instead). + */ + + if (rtcb->nchildren == 0 || + (pid != (pid_t)-1 && (ret = kill(pid, 0)) < 0)) + { + /* We know that the child task was running okay we stared, + * so we must have lost the signal. What can we do? + * Let's claim we were interrupted by a signal. + */ + + err = EINTR; + goto errout_with_errno; + } +#endif /* Wait for any death-of-child signal */ @@ -447,7 +486,7 @@ pid_t waitpid(pid_t pid, int *stat_loc, int options) { /* Yes... return the status and PID (in the event it was -1) */ - *stat_loc = info.si_status; + *stat_loc = info.si_status << 8; pid = info.si_pid; break; } |