uloop: handle EPOLLHUP like EPOLLERR to prevent infinite tight loops between epoll_wa...
[project/libubox.git] / uloop.c
diff --git a/uloop.c b/uloop.c
index ec37925..38da5f6 100644 (file)
--- a/uloop.c
+++ b/uloop.c
 #include <sys/time.h>
 #include <sys/types.h>
 
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <poll.h>
+#include <string.h>
+#include <fcntl.h>
+#include <stdbool.h>
+
 #include "uloop.h"
 
 #ifdef USE_KQUEUE
 #ifdef USE_EPOLL
 #include <sys/epoll.h>
 #endif
+#include <sys/wait.h>
 
-#include <unistd.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <poll.h>
-#include <string.h>
-#include <fcntl.h>
-#include <signal.h>
-#include <stdbool.h>
 
 #ifndef ARRAY_SIZE
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 #endif
 #define ULOOP_MAX_EVENTS 10
 
-struct uloop_timeout *first_timeout;
-static int poll_fd;
-static bool cancel;
+static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
+static struct list_head processes = LIST_HEAD_INIT(processes);
+
+static int poll_fd = -1;
+bool uloop_cancelled = false;
+bool uloop_handle_sigchld = true;
+static bool do_sigchld = false;
 
 #ifdef USE_KQUEUE
 
 int uloop_init(void)
 {
+       if (poll_fd >= 0)
+               return 0;
+
        poll_fd = kqueue();
        if (poll_fd < 0)
                return -1;
@@ -94,7 +102,7 @@ static int register_poll(struct uloop_fd *fd, unsigned int flags)
 
        if (changed & ULOOP_WRITE) {
                uint16_t kflags = get_flags(flags, ULOOP_WRITE);
-               EV_SET(&ev[nev++], fd->fd, EVFILT_READ, kflags, 0, 0, fd);
+               EV_SET(&ev[nev++], fd->fd, EVFILT_WRITE, kflags, 0, 0, fd);
        }
 
        if (nev && (kevent(poll_fd, ev, nev, NULL, 0, &timeout) == -1))
@@ -118,7 +126,7 @@ static void uloop_run_events(int timeout)
 
        if (timeout > 0) {
                ts.tv_sec = timeout / 1000;
-               ts.tv_nsec = timeout * 1000000;
+               ts.tv_nsec = (timeout % 1000) * 1000000;
        }
 
        nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout > 0 ? &ts : NULL);
@@ -160,6 +168,9 @@ static void uloop_run_events(int timeout)
 
 int uloop_init(void)
 {
+       if (poll_fd >= 0)
+               return 0;
+
        poll_fd = epoll_create(32);
        if (poll_fd < 0)
                return -1;
@@ -190,16 +201,26 @@ static int register_poll(struct uloop_fd *fd, unsigned int flags)
        return epoll_ctl(poll_fd, op, fd->fd, &ev);
 }
 
+static int cur_fd, cur_nfds;
+static struct epoll_event events[ULOOP_MAX_EVENTS];
+
 int uloop_fd_delete(struct uloop_fd *sock)
 {
+       int i;
+
+       for (i = cur_fd + 1; i < cur_nfds; i++) {
+               if (events[i].data.ptr != sock)
+                       continue;
+
+               events[i].data.ptr = NULL;
+       }
        sock->registered = false;
        return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 }
 
 static void uloop_run_events(int timeout)
 {
-       struct epoll_event events[ULOOP_MAX_EVENTS];
-       int nfds, n;
+       int n, nfds;
 
        nfds = epoll_wait(poll_fd, events, ARRAY_SIZE(events), timeout);
        for(n = 0; n < nfds; ++n)
@@ -207,12 +228,15 @@ static void uloop_run_events(int timeout)
                struct uloop_fd *u = events[n].data.ptr;
                unsigned int ev = 0;
 
-               if(events[n].events & EPOLLERR) {
+               if (!u)
+                       continue;
+
+               if(events[n].events & (EPOLLERR|EPOLLHUP)) {
                        u->error = true;
                        uloop_fd_delete(u);
                }
 
-               if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR)))
+               if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP)))
                        continue;
 
                if(events[n].events & EPOLLRDHUP)
@@ -224,9 +248,13 @@ static void uloop_run_events(int timeout)
                if(events[n].events & EPOLLOUT)
                        ev |= ULOOP_WRITE;
 
-               if(u->cb)
+               if(u->cb) {
+                       cur_fd = n;
+                       cur_nfds = nfds;
                        u->cb(u, ev);
+               }
        }
+       cur_nfds = 0;
 }
 
 #endif
@@ -236,7 +264,7 @@ int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
        unsigned int fl;
        int ret;
 
-       if (!sock->registered) {
+       if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
                fl = fcntl(sock->fd, F_GETFL, 0);
                fl |= O_NONBLOCK;
                fcntl(sock->fd, F_SETFL, fl);
@@ -263,25 +291,20 @@ static int tv_diff(struct timeval *t1, struct timeval *t2)
 
 int uloop_timeout_add(struct uloop_timeout *timeout)
 {
-       struct uloop_timeout **head = &first_timeout;
-       struct uloop_timeout *prev = NULL;
+       struct uloop_timeout *tmp;
+       struct list_head *h = &timeouts;
 
        if (timeout->pending)
                return -1;
 
-       while (*head) {
-               if (tv_diff(&(*head)->time, &timeout->time) > 0)
+       list_for_each_entry(tmp, &timeouts, list) {
+               if (tv_diff(&tmp->time, &timeout->time) > 0) {
+                       h = &tmp->list;
                        break;
-
-               prev = *head;
-               head = &(*head)->next;
+               }
        }
 
-       timeout->prev = prev;
-       timeout->next = *head;
-       if (timeout->next)
-               timeout->next->prev = timeout;
-       *head = timeout;
+       list_add_tail(&timeout->list, h);
        timeout->pending = true;
 
        return 0;
@@ -312,41 +335,106 @@ int uloop_timeout_cancel(struct uloop_timeout *timeout)
        if (!timeout->pending)
                return -1;
 
-       if (timeout->prev)
-               timeout->prev->next = timeout->next;
-       else
-               first_timeout = timeout->next;
+       list_del(&timeout->list);
+       timeout->pending = false;
 
-       if (timeout->next)
-               timeout->next->prev = timeout->prev;
+       return 0;
+}
 
-       timeout->pending = false;
+int uloop_process_add(struct uloop_process *p)
+{
+       struct uloop_process *tmp;
+       struct list_head *h = &processes;
+
+       if (p->pending)
+               return -1;
+
+       list_for_each_entry(tmp, &processes, list) {
+               if (tmp->pid > p->pid) {
+                       h = &tmp->list;
+                       break;
+               }
+       }
+
+       list_add_tail(&p->list, h);
+       p->pending = true;
 
        return 0;
 }
 
+int uloop_process_delete(struct uloop_process *p)
+{
+       if (!p->pending)
+               return -1;
+
+       list_del(&p->list);
+       p->pending = false;
+
+       return 0;
+}
+
+static void uloop_handle_processes(void)
+{
+       struct uloop_process *p, *tmp;
+       pid_t pid;
+       int ret;
+
+       do_sigchld = false;
+
+       while (1) {
+               pid = waitpid(-1, &ret, WNOHANG);
+               if (pid <= 0)
+                       return;
+
+               list_for_each_entry_safe(p, tmp, &processes, list) {
+                       if (p->pid < pid)
+                               continue;
+
+                       if (p->pid > pid)
+                               break;
+
+                       uloop_process_delete(p);
+                       p->cb(p, ret);
+               }
+       }
+
+}
+
 static void uloop_handle_sigint(int signo)
 {
-       cancel = true;
+       uloop_cancelled = true;
+}
+
+static void uloop_sigchld(int signo)
+{
+       do_sigchld = true;
 }
 
 static void uloop_setup_signals(void)
 {
        struct sigaction s;
+
        memset(&s, 0, sizeof(struct sigaction));
        s.sa_handler = uloop_handle_sigint;
        s.sa_flags = 0;
        sigaction(SIGINT, &s, NULL);
+
+       if (uloop_handle_sigchld) {
+               s.sa_handler = uloop_sigchld;
+               sigaction(SIGCHLD, &s, NULL);
+       }
 }
 
 static int uloop_get_next_timeout(struct timeval *tv)
 {
+       struct uloop_timeout *timeout;
        int diff;
 
-       if (!first_timeout)
+       if (list_empty(&timeouts))
                return -1;
 
-       diff = tv_diff(&first_timeout->time, tv);
+       timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
+       diff = tv_diff(&timeout->time, tv);
        if (diff < 0)
                return 0;
 
@@ -355,38 +443,41 @@ static int uloop_get_next_timeout(struct timeval *tv)
 
 static void uloop_process_timeouts(struct timeval *tv)
 {
-       struct uloop_timeout *timeout;
+       struct uloop_timeout *t, *tmp;
 
-       while (first_timeout) {
-               if (tv_diff(&first_timeout->time, tv) > 0)
+       list_for_each_entry_safe(t, tmp, &timeouts, list) {
+               if (tv_diff(&t->time, tv) > 0)
                        break;
 
-               timeout = first_timeout;
-               uloop_timeout_cancel(timeout);
-               if (timeout->cb)
-                       timeout->cb(timeout);
+               uloop_timeout_cancel(t);
+               if (t->cb)
+                       t->cb(t);
        }
 }
 
-void uloop_end(void)
-{
-       cancel = true;
-}
-
 void uloop_run(void)
 {
        struct timeval tv;
 
        uloop_setup_signals();
-       while(!cancel)
+       while(!uloop_cancelled)
        {
                gettimeofday(&tv, NULL);
                uloop_process_timeouts(&tv);
+               if (uloop_cancelled)
+                       break;
+
+               if (do_sigchld)
+                       uloop_handle_processes();
                uloop_run_events(uloop_get_next_timeout(&tv));
        }
 }
 
 void uloop_done(void)
 {
+       if (poll_fd < 0)
+               return;
+
        close(poll_fd);
+       poll_fd = -1;
 }