uloop: ignore SIGPIPE by default
[project/libubox.git] / uloop.c
diff --git a/uloop.c b/uloop.c
index f60eb41..9ebeca6 100644 (file)
--- a/uloop.c
+++ b/uloop.c
@@ -1,36 +1,23 @@
 /*
- *   Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
- *   Copyright (C) 2010 John Crispin <blogic@openwrt.org>
- *   Copyright (C) 2010 Steven Barth <steven@midlink.org>
+ * uloop - event loop implementation
  *
- *   This program is free software; you can redistribute it and/or modify
- *   it under the terms of the GNU General Public License as published by
- *   the Free Software Foundation; either version 2 of the License, or
- *   (at your option) any later version.
+ * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
  *
- *   This program is distributed in the hope that it will be useful,
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *   GNU General Public License for more details.
- *
- *   You should have received a copy of the GNU General Public License
- *   along with this program; if not, write to the Free Software
- *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
  *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
-
 #include <sys/time.h>
 #include <sys/types.h>
 
-#include "uloop.h"
-
-#ifdef USE_KQUEUE
-#include <sys/event.h>
-#endif
-#ifdef USE_EPOLL
-#include <sys/epoll.h>
-#endif
-
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.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]))
+#include "uloop.h"
+#include "utils.h"
+
+#ifdef USE_KQUEUE
+#include <sys/event.h>
+#endif
+#ifdef USE_EPOLL
+#include <sys/epoll.h>
 #endif
+#include <sys/wait.h>
+
+struct uloop_fd_event {
+       struct uloop_fd *fd;
+       unsigned int events;
+};
+
+struct uloop_fd_stack {
+       struct uloop_fd_stack *next;
+       struct uloop_fd *fd;
+       unsigned int events;
+};
+
+static struct uloop_fd_stack *fd_stack = NULL;
+
 #define ULOOP_MAX_EVENTS 10
 
-static struct uloop_timeout *first_timeout;
+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;
+static bool do_sigchld = false;
+
+static struct uloop_fd_event cur_fds[ULOOP_MAX_EVENTS];
+static int cur_fd, cur_nfds;
 
 #ifdef USE_KQUEUE
 
 int uloop_init(void)
 {
+       struct timespec timeout = { 0, 0 };
+       struct kevent ev = {};
+
        if (poll_fd >= 0)
                return 0;
 
@@ -61,6 +77,9 @@ int uloop_init(void)
        if (poll_fd < 0)
                return -1;
 
+       EV_SET(&ev, SIGCHLD, EVFILT_SIGNAL, EV_ADD, 0, 0, 0);
+       kevent(poll_fd, &ev, 1, NULL, 0, &timeout);
+
        return 0;
 }
 
@@ -79,60 +98,83 @@ static uint16_t get_flags(unsigned int flags, unsigned int mask)
        return kflags;
 }
 
-static int register_poll(struct uloop_fd *fd, unsigned int flags)
+static struct kevent events[ULOOP_MAX_EVENTS];
+
+static int register_kevent(struct uloop_fd *fd, unsigned int flags)
 {
        struct timespec timeout = { 0, 0 };
        struct kevent ev[2];
-       unsigned int changed;
        int nev = 0;
+       unsigned int fl = 0;
+       unsigned int changed;
+       uint16_t kflags;
+
+       if (flags & ULOOP_EDGE_DEFER)
+               flags &= ~ULOOP_EDGE_TRIGGER;
 
-       changed = fd->kqflags ^ flags;
+       changed = flags ^ fd->flags;
        if (changed & ULOOP_EDGE_TRIGGER)
                changed |= flags;
 
        if (changed & ULOOP_READ) {
-               uint16_t kflags = get_flags(flags, ULOOP_READ);
+               kflags = get_flags(flags, ULOOP_READ);
                EV_SET(&ev[nev++], fd->fd, EVFILT_READ, kflags, 0, 0, fd);
        }
 
        if (changed & ULOOP_WRITE) {
-               uint16_t kflags = get_flags(flags, ULOOP_WRITE);
+               kflags = get_flags(flags, ULOOP_WRITE);
                EV_SET(&ev[nev++], fd->fd, EVFILT_WRITE, kflags, 0, 0, fd);
        }
 
-       if (nev && (kevent(poll_fd, ev, nev, NULL, 0, &timeout) == -1))
+       if (!flags)
+               fl |= EV_DELETE;
+
+       fd->flags = flags;
+       if (kevent(poll_fd, ev, nev, NULL, fl, &timeout) == -1)
                return -1;
 
-       fd->kqflags = flags;
        return 0;
 }
 
-int uloop_fd_delete(struct uloop_fd *sock)
+static int register_poll(struct uloop_fd *fd, unsigned int flags)
+{
+       if (flags & ULOOP_EDGE_TRIGGER)
+               flags |= ULOOP_EDGE_DEFER;
+       else
+               flags &= ~ULOOP_EDGE_DEFER;
+
+       return register_kevent(fd, flags);
+}
+
+static int __uloop_fd_delete(struct uloop_fd *fd)
 {
-       sock->registered = false;
-       return register_poll(sock, 0);
+       return register_poll(fd, 0);
 }
 
-static void uloop_run_events(int timeout)
+static int uloop_fetch_events(int timeout)
 {
-       struct kevent events[ULOOP_MAX_EVENTS];
        struct timespec ts;
        int nfds, n;
 
-       if (timeout > 0) {
+       if (timeout >= 0) {
                ts.tv_sec = timeout / 1000;
                ts.tv_nsec = (timeout % 1000) * 1000000;
        }
 
-       nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout > 0 ? &ts : NULL);
-       for(n = 0; n < nfds; ++n)
-       {
+       nfds = kevent(poll_fd, NULL, 0, events, ARRAY_SIZE(events), timeout >= 0 ? &ts : NULL);
+       for (n = 0; n < nfds; n++) {
+               struct uloop_fd_event *cur = &cur_fds[n];
                struct uloop_fd *u = events[n].udata;
                unsigned int ev = 0;
 
-               if(events[n].flags & EV_ERROR) {
+               cur->fd = u;
+               if (!u)
+                       continue;
+
+               if (events[n].flags & EV_ERROR) {
                        u->error = true;
-                       uloop_fd_delete(u);
+                       if (!(u->flags & ULOOP_ERROR_CB))
+                               uloop_fd_delete(u);
                }
 
                if(events[n].filter == EVFILT_READ)
@@ -140,14 +182,19 @@ static void uloop_run_events(int timeout)
                else if (events[n].filter == EVFILT_WRITE)
                        ev |= ULOOP_WRITE;
 
-               if(events[n].flags & EV_EOF)
+               if (events[n].flags & EV_EOF)
                        u->eof = true;
                else if (!ev)
-                       continue;
+                       cur->fd = NULL;
 
-               if(u->cb)
-                       u->cb(u, ev);
+               cur->events = ev;
+               if (u->flags & ULOOP_EDGE_DEFER) {
+                       u->flags &= ~ULOOP_EDGE_DEFER;
+                       u->flags |= ULOOP_EDGE_TRIGGER;
+                       register_kevent(u, u->flags);
+               }
        }
+       return nfds;
 }
 
 #endif
@@ -192,34 +239,43 @@ static int register_poll(struct uloop_fd *fd, unsigned int flags)
 
        ev.data.fd = fd->fd;
        ev.data.ptr = fd;
+       fd->flags = flags;
 
        return epoll_ctl(poll_fd, op, fd->fd, &ev);
 }
 
-int uloop_fd_delete(struct uloop_fd *sock)
+static struct epoll_event events[ULOOP_MAX_EVENTS];
+
+static int __uloop_fd_delete(struct uloop_fd *sock)
 {
-       sock->registered = false;
+       sock->flags = 0;
        return epoll_ctl(poll_fd, EPOLL_CTL_DEL, sock->fd, 0);
 }
 
-static void uloop_run_events(int timeout)
+static int uloop_fetch_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)
-       {
+       for (n = 0; n < nfds; ++n) {
+               struct uloop_fd_event *cur = &cur_fds[n];
                struct uloop_fd *u = events[n].data.ptr;
                unsigned int ev = 0;
 
-               if(events[n].events & EPOLLERR) {
+               cur->fd = u;
+               if (!u)
+                       continue;
+
+               if (events[n].events & (EPOLLERR|EPOLLHUP)) {
                        u->error = true;
-                       uloop_fd_delete(u);
+                       if (!(u->flags & ULOOP_ERROR_CB))
+                               uloop_fd_delete(u);
                }
 
-               if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR)))
+               if(!(events[n].events & (EPOLLRDHUP|EPOLLIN|EPOLLOUT|EPOLLERR|EPOLLHUP))) {
+                       cur->fd = NULL;
                        continue;
+               }
 
                if(events[n].events & EPOLLRDHUP)
                        u->eof = true;
@@ -230,18 +286,92 @@ static void uloop_run_events(int timeout)
                if(events[n].events & EPOLLOUT)
                        ev |= ULOOP_WRITE;
 
-               if(u->cb)
-                       u->cb(u, ev);
+               cur->events = ev;
        }
+
+       return nfds;
 }
 
 #endif
 
+static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
+{
+       struct uloop_fd_stack *cur;
+
+       /*
+        * Do not buffer events for level-triggered fds, they will keep firing.
+        * Caller needs to take care of recursion issues.
+        */
+       if (!(fd->flags & ULOOP_EDGE_TRIGGER))
+               return false;
+
+       for (cur = fd_stack; cur; cur = cur->next) {
+               if (cur->fd != fd)
+                       continue;
+
+               if (events < 0)
+                       cur->fd = NULL;
+               else
+                       cur->events |= events | ULOOP_EVENT_BUFFERED;
+
+               return true;
+       }
+
+       return false;
+}
+
+static void uloop_run_events(int timeout)
+{
+       struct uloop_fd_event *cur;
+       struct uloop_fd *fd;
+
+       if (!cur_nfds) {
+               cur_fd = 0;
+               cur_nfds = uloop_fetch_events(timeout);
+               if (cur_nfds < 0)
+                       cur_nfds = 0;
+       }
+
+       while (cur_nfds > 0) {
+               struct uloop_fd_stack stack_cur;
+               unsigned int events;
+
+               cur = &cur_fds[cur_fd++];
+               cur_nfds--;
+
+               fd = cur->fd;
+               events = cur->events;
+               if (!fd)
+                       continue;
+
+               if (!fd->cb)
+                       continue;
+
+               if (uloop_fd_stack_event(fd, cur->events))
+                       continue;
+
+               stack_cur.next = fd_stack;
+               stack_cur.fd = fd;
+               fd_stack = &stack_cur;
+               do {
+                       stack_cur.events = 0;
+                       fd->cb(fd, events);
+                       events = stack_cur.events & ULOOP_EVENT_MASK;
+               } while (stack_cur.fd && events);
+               fd_stack = stack_cur.next;
+
+               return;
+       }
+}
+
 int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 {
        unsigned int fl;
        int ret;
 
+       if (!(flags & (ULOOP_READ | ULOOP_WRITE)))
+               return uloop_fd_delete(sock);
+
        if (!sock->registered && !(flags & ULOOP_BLOCKING)) {
                fl = fcntl(sock->fd, F_GETFL, 0);
                fl |= O_NONBLOCK;
@@ -254,45 +384,68 @@ int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
 
        sock->registered = true;
        sock->eof = false;
+       sock->error = false;
 
 out:
        return ret;
 }
 
+int uloop_fd_delete(struct uloop_fd *fd)
+{
+       int i;
+
+       for (i = 0; i < cur_nfds; i++) {
+               if (cur_fds[cur_fd + i].fd != fd)
+                       continue;
+
+               cur_fds[cur_fd + i].fd = NULL;
+       }
+
+       if (!fd->registered)
+               return 0;
+
+       fd->registered = false;
+       uloop_fd_stack_event(fd, -1);
+       return __uloop_fd_delete(fd);
+}
+
 static int tv_diff(struct timeval *t1, struct timeval *t2)
 {
-       if (t1->tv_sec != t2->tv_sec)
-               return (t1->tv_sec - t2->tv_sec) * 1000;
-       else
-               return (t1->tv_usec - t2->tv_usec) / 1000;
+       return
+               (t1->tv_sec - t2->tv_sec) * 1000 +
+               (t1->tv_usec - t2->tv_usec) / 1000;
 }
 
 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;
 }
 
+static void uloop_gettime(struct timeval *tv)
+{
+       struct timespec ts;
+
+       clock_gettime(CLOCK_MONOTONIC, &ts);
+       tv->tv_sec = ts.tv_sec;
+       tv->tv_usec = ts.tv_nsec / 1000;
+}
+
 int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
 {
        struct timeval *time = &timeout->time;
@@ -300,14 +453,14 @@ int uloop_timeout_set(struct uloop_timeout *timeout, int msecs)
        if (timeout->pending)
                uloop_timeout_cancel(timeout);
 
-       gettimeofday(&timeout->time, NULL);
+       uloop_gettime(time);
 
        time->tv_sec += msecs / 1000;
-       time->tv_usec += msecs % 1000;
+       time->tv_usec += (msecs % 1000) * 1000;
 
        if (time->tv_usec > 1000000) {
                time->tv_sec++;
-               time->tv_usec %= 100000;
+               time->tv_usec -= 1000000;
        }
 
        return uloop_timeout_add(timeout);
@@ -318,41 +471,160 @@ 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_timeout_remaining(struct uloop_timeout *timeout)
+{
+       struct timeval now;
+
+       if (!timeout->pending)
+               return -1;
+
+       uloop_gettime(&now);
+
+       return tv_diff(&timeout->time, &now);
+}
+
+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)
 {
        uloop_cancelled = true;
 }
 
-static void uloop_setup_signals(void)
+static void uloop_sigchld(int signo)
+{
+       do_sigchld = true;
+}
+
+static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
+{
+       struct sigaction s;
+       struct sigaction *act;
+
+       act = NULL;
+       sigaction(signum, NULL, &s);
+
+       if (add) {
+               if (s.sa_handler == SIG_DFL) { /* Do not override existing custom signal handlers */
+                       memcpy(old, &s, sizeof(struct sigaction));
+                       s.sa_handler = handler;
+                       s.sa_flags = 0;
+                       act = &s;
+               }
+       }
+       else if (s.sa_handler == handler) { /* Do not restore if someone modified our handler */
+                       act = old;
+       }
+
+       if (act != NULL)
+               sigaction(signum, act, NULL);
+}
+
+static void uloop_ignore_signal(int signum, bool ignore)
 {
        struct sigaction s;
-       memset(&s, 0, sizeof(struct sigaction));
-       s.sa_handler = uloop_handle_sigint;
-       s.sa_flags = 0;
-       sigaction(SIGINT, &s, NULL);
+       void *new_handler = NULL;
+
+       sigaction(signum, NULL, &s);
+
+       if (ignore) {
+               if (s.sa_handler == SIG_DFL) /* Ignore only if there isn't any custom handler */
+                       new_handler = SIG_IGN;
+       } else {
+               if (s.sa_handler == SIG_IGN) /* Restore only if noone modified our SIG_IGN */
+                       new_handler = SIG_DFL;
+       }
+
+       if (new_handler) {
+               s.sa_handler = new_handler;
+               s.sa_flags = 0;
+               sigaction(signum, &s, NULL);
+       }
+}
+
+static void uloop_setup_signals(bool add)
+{
+       static struct sigaction old_sigint, old_sigchld, old_sigterm;
+
+       uloop_install_handler(SIGINT, uloop_handle_sigint, &old_sigint, add);
+       uloop_install_handler(SIGTERM, uloop_handle_sigint, &old_sigterm, add);
+       uloop_install_handler(SIGCHLD, uloop_sigchld, &old_sigchld, add);
+
+       uloop_ignore_signal(SIGPIPE, add);
 }
 
 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;
 
@@ -361,32 +633,64 @@ 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;
+
+       while (!list_empty(&timeouts)) {
+               t = list_first_entry(&timeouts, struct uloop_timeout, list);
 
-       while (first_timeout) {
-               if (tv_diff(&first_timeout->time, tv) > 0)
+               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);
        }
 }
 
+static void uloop_clear_timeouts(void)
+{
+       struct uloop_timeout *t, *tmp;
+
+       list_for_each_entry_safe(t, tmp, &timeouts, list)
+               uloop_timeout_cancel(t);
+}
+
+static void uloop_clear_processes(void)
+{
+       struct uloop_process *p, *tmp;
+
+       list_for_each_entry_safe(p, tmp, &processes, list)
+               uloop_process_delete(p);
+}
+
 void uloop_run(void)
 {
+       static int recursive_calls = 0;
        struct timeval tv;
 
-       uloop_setup_signals();
+       /*
+        * Handlers are only updated for the first call to uloop_run() (and restored
+        * when this call is done).
+        */
+       if (!recursive_calls++)
+               uloop_setup_signals(true);
+
+       uloop_cancelled = false;
        while(!uloop_cancelled)
        {
-               gettimeofday(&tv, NULL);
+               uloop_gettime(&tv);
                uloop_process_timeouts(&tv);
                if (uloop_cancelled)
                        break;
+
+               if (do_sigchld)
+                       uloop_handle_processes();
+               uloop_gettime(&tv);
                uloop_run_events(uloop_get_next_timeout(&tv));
        }
+
+       if (!--recursive_calls)
+               uloop_setup_signals(false);
 }
 
 void uloop_done(void)
@@ -396,4 +700,7 @@ void uloop_done(void)
 
        close(poll_fd);
        poll_fd = -1;
+
+       uloop_clear_timeouts();
+       uloop_clear_processes();
 }