diff options
Diffstat (limited to 'nuttx/sched/sched_waitid.c')
| -rw-r--r-- | nuttx/sched/sched_waitid.c | 149 |
1 files changed, 113 insertions, 36 deletions
diff --git a/nuttx/sched/sched_waitid.c b/nuttx/sched/sched_waitid.c index 37ee26ce0..9c24189c4 100644 --- a/nuttx/sched/sched_waitid.c +++ b/nuttx/sched/sched_waitid.c @@ -46,6 +46,7 @@ #include <nuttx/sched.h> #include "os_internal.h" +#include "group_internal.h" #if defined(CONFIG_SCHED_WAITPID) && defined(CONFIG_SCHED_HAVE_PARENT) @@ -54,6 +55,36 @@ *****************************************************************************/ /***************************************************************************** + * Name: exited_child + * + * Description: + * Handle the case where a child exited properlay was we (apparently) lost + * the detch of child signal. + * + *****************************************************************************/ + +#ifdef CONFIG_SCHED_CHILD_STATUS +static void exited_child(FAR _TCB *rtcb, FAR struct child_status_s *child, + FAR siginfo_t *info) +{ + /* The child has exited. Return the saved exit status (and some fudged + * information. + */ + + info->si_signo = SIGCHLD; + info->si_code = CLD_EXITED; + info->si_value.sival_ptr = NULL; + info->si_pid = child->ch_pid; + info->si_status = child->ch_status; + + /* Discard the child entry */ + + (void)group_removechild(rtcb->group, child->ch_pid); + group_freechild(child); +} +#endif + +/***************************************************************************** * Public Functions *****************************************************************************/ @@ -120,9 +151,14 @@ * *****************************************************************************/ -int waitid(idtype_t idtype, id_t id, siginfo_t *info, int options) +int waitid(idtype_t idtype, id_t id, FAR siginfo_t *info, 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 sigset_t sigset; int err; int ret; @@ -160,7 +196,11 @@ int waitid(idtype_t idtype, id_t id, siginfo_t *info, int options) */ #ifdef CONFIG_SCHED_CHILD_STATUS - if (rtcb->children == NULL) + /* Does this task retain child status? */ + + retains = ((rtcb->group->tg_flags && GROUP_FLAG_NOCLDWAIT) == 0); + + if (rtcb->group->tg_children == NULL && retains) { /* There are no children */ @@ -169,13 +209,33 @@ int waitid(idtype_t idtype, id_t id, siginfo_t *info, int options) } else if (idtype == P_PID) { - if (task_findchild(rtcb, (pid_t)id) == NULL) - { - /* This specific pid is not a child */ + /* Get the TCB corresponding to this PID and make sure it is our child. */ + ctcb = sched_gettcb((pid_t)id); +#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_t)id) == NULL) + { + /* This specific pid is not a child */ + + err = ECHILD; + goto errout_with_errno; + } + } } #else if (rtcb->nchildren == 0) @@ -189,8 +249,12 @@ int waitid(idtype_t idtype, id_t id, siginfo_t *info, int options) { /* Get the TCB corresponding to this PID and make sure it is our child. */ - FAR _TCB *ctcb = sched_gettcb((pid_t)id); - if (!ctcb || ctcb->parent != rtcb->pid) + ctcb = sched_gettcb((pid_t)id); +#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; @@ -209,48 +273,61 @@ int waitid(idtype_t idtype, id_t id, siginfo_t *info, int options) * instead). */ - DEBUGASSERT(rtcb->children); - if (rtcb->children == NULL) + DEBUGASSERT(!retains || rtcb->group->tg_children); + if (idtype == P_ALL) { - /* This should not happen. I am just wasting your FLASH. */ + /* We are waiting for any child to exit */ - err = ECHILD; - goto errout_with_errno; - } - else if (idtype == P_PID) - { - FAR struct child_status_s *child; - - /* We are waiting for a specific PID. Get the current status - * of the child task. - */ - - child = task_findchild(rtcb, (pid_t)id); - DEBUGASSERT(child); - if (!child) + if (retains && (child = group_exitchild(rtcb->group)) != NULL) { - /* Yikes! The child status entry just disappeared! */ + /* A child has exited. Apparently we missed the signal. + * Return the exit status and break out of the loop. + */ - err = ECHILD; - goto errout_with_errno; + exited_child(rtcb, child, info); + break; } + } + /* We are waiting for a specific PID. Does this task retain child status? */ + + else if (retains) + { + /* Yes ... Get the current status of the child task. */ + + child = group_findchild(rtcb->group, (pid_t)id); + DEBUGASSERT(child); + /* Did the child exit? */ if ((child->ch_flags & CHILD_FLAG_EXITED) != 0) { - /* The child has exited. Return the saved exit status */ + /* The child has exited. Return the exit status and break out + * of the loop. + */ - info->si_signo = SIGCHLD; - info->si_code = CLD_EXITED; - info->si_value.sival_ptr = NULL; - info->si_pid = (pid_t)id; - info->si_status = child->ch_status; + exited_child(rtcb, child, info); + break; + } + } + else + { + /* We can use kill() with signal number 0 to determine if that + * task is still alive. + */ - /* Discard the child entry and break out of the loop */ + ret = kill((pid_t)id, 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 than bogus status. + */ - (void)task_removechild(rtcb, (pid_t)id); - task_freechild(child); + err = ECHILD; + goto errout_with_errno; } } #else |