ustream: prevent recursive calls to the read callback
[project/libubox.git] / uloop.c
diff --git a/uloop.c b/uloop.c
index d2784b772bb490ffefd348aa1ee341ff6833d07a..da6f690cfad63f100f38510d087e81350cc1ea2b 100644 (file)
--- a/uloop.c
+++ b/uloop.c
@@ -26,6 +26,7 @@
 #include <string.h>
 #include <fcntl.h>
 #include <stdbool.h>
+#include <limits.h>
 
 #include "uloop.h"
 #include "utils.h"
@@ -35,6 +36,7 @@
 #endif
 #ifdef USE_EPOLL
 #include <sys/epoll.h>
+#include <sys/timerfd.h>
 #endif
 #include <sys/wait.h>
 
@@ -55,13 +57,21 @@ static struct uloop_fd_stack *fd_stack = NULL;
 
 static struct list_head timeouts = LIST_HEAD_INIT(timeouts);
 static struct list_head processes = LIST_HEAD_INIT(processes);
+static struct list_head signals = LIST_HEAD_INIT(signals);
 
 static int poll_fd = -1;
 bool uloop_cancelled = false;
+bool uloop_handle_sigchld = true;
+static int uloop_status = 0;
 static bool do_sigchld = false;
 
 static struct uloop_fd_event cur_fds[ULOOP_MAX_EVENTS];
 static int cur_fd, cur_nfds;
+static int uloop_run_depth = 0;
+
+uloop_fd_handler uloop_fd_set_cb = NULL;
+
+int uloop_fd_add(struct uloop_fd *sock, unsigned int flags);
 
 #ifdef USE_KQUEUE
 #include "uloop-kqueue.c"
@@ -71,6 +81,87 @@ static int cur_fd, cur_nfds;
 #include "uloop-epoll.c"
 #endif
 
+static void set_signo(uint64_t *signums, int signo)
+{
+       if (signo >= 1 && signo <= 64)
+               *signums |= (1u << (signo - 1));
+}
+
+static bool get_signo(uint64_t signums, int signo)
+{
+       return (signo >= 1) && (signo <= 64) && (signums & (1u << (signo - 1)));
+}
+
+static void signal_consume(struct uloop_fd *fd, unsigned int events)
+{
+       struct uloop_signal *usig, *usig_next;
+       uint64_t signums = 0;
+       uint8_t buf[32];
+       ssize_t nsigs;
+
+       do {
+               nsigs = read(fd->fd, buf, sizeof(buf));
+
+               for (ssize_t i = 0; i < nsigs; i++)
+                       set_signo(&signums, buf[i]);
+       }
+       while (nsigs > 0);
+
+       list_for_each_entry_safe(usig, usig_next, &signals, list)
+               if (get_signo(signums, usig->signo))
+                       usig->cb(usig);
+}
+
+static int waker_pipe = -1;
+static struct uloop_fd waker_fd = {
+       .fd = -1,
+       .cb = signal_consume,
+};
+
+static void waker_init_fd(int fd)
+{
+       fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+       fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);
+}
+
+static int waker_init(void)
+{
+       int fds[2];
+
+       if (waker_pipe >= 0)
+               return 0;
+
+       if (pipe(fds) < 0)
+               return -1;
+
+       waker_init_fd(fds[0]);
+       waker_init_fd(fds[1]);
+       waker_pipe = fds[1];
+
+       waker_fd.fd = fds[0];
+       waker_fd.cb = signal_consume;
+       uloop_fd_add(&waker_fd, ULOOP_READ);
+
+       return 0;
+}
+
+static void uloop_setup_signals(bool add);
+
+int uloop_init(void)
+{
+       if (uloop_init_pollfd() < 0)
+               return -1;
+
+       if (waker_init() < 0) {
+               uloop_done();
+               return -1;
+       }
+
+       uloop_setup_signals(true);
+
+       return 0;
+}
+
 static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
 {
        struct uloop_fd_stack *cur;
@@ -97,7 +188,7 @@ static bool uloop_fd_stack_event(struct uloop_fd *fd, int events)
        return false;
 }
 
-static void uloop_run_events(int timeout)
+static void uloop_run_events(int64_t timeout)
 {
        struct uloop_fd_event *cur;
        struct uloop_fd *fd;
@@ -159,6 +250,10 @@ int uloop_fd_add(struct uloop_fd *sock, unsigned int flags)
        if (ret < 0)
                goto out;
 
+       if (uloop_fd_set_cb)
+               uloop_fd_set_cb(sock, flags);
+
+       sock->flags = flags;
        sock->registered = true;
        sock->eof = false;
        sock->error = false;
@@ -169,6 +264,7 @@ out:
 
 int uloop_fd_delete(struct uloop_fd *fd)
 {
+       int ret;
        int i;
 
        for (i = 0; i < cur_nfds; i++) {
@@ -181,12 +277,18 @@ int uloop_fd_delete(struct uloop_fd *fd)
        if (!fd->registered)
                return 0;
 
+       if (uloop_fd_set_cb)
+               uloop_fd_set_cb(fd, 0);
+
        fd->registered = false;
        uloop_fd_stack_event(fd, -1);
-       return __uloop_fd_delete(fd);
+       ret = __uloop_fd_delete(fd);
+       fd->flags = 0;
+
+       return ret;
 }
 
-static int tv_diff(struct timeval *t1, struct timeval *t2)
+static int64_t tv_diff(struct timeval *t1, struct timeval *t2)
 {
        return
                (t1->tv_sec - t2->tv_sec) * 1000 +
@@ -255,6 +357,26 @@ int uloop_timeout_cancel(struct uloop_timeout *timeout)
 }
 
 int uloop_timeout_remaining(struct uloop_timeout *timeout)
+{
+       int64_t td;
+       struct timeval now;
+
+       if (!timeout->pending)
+               return -1;
+
+       uloop_gettime(&now);
+
+       td = tv_diff(&timeout->time, &now);
+
+       if (td > INT_MAX)
+               return INT_MAX;
+       else if (td < INT_MIN)
+               return INT_MIN;
+       else
+               return (int)td;
+}
+
+int64_t uloop_timeout_remaining64(struct uloop_timeout *timeout)
 {
        struct timeval now;
 
@@ -308,6 +430,9 @@ static void uloop_handle_processes(void)
 
        while (1) {
                pid = waitpid(-1, &ret, WNOHANG);
+               if (pid < 0 && errno == EINTR)
+                       continue;
+
                if (pid <= 0)
                        return;
 
@@ -325,14 +450,42 @@ static void uloop_handle_processes(void)
 
 }
 
-static void uloop_handle_sigint(int signo)
+int uloop_interval_set(struct uloop_interval *timer, unsigned int msecs)
 {
-       uloop_cancelled = true;
+       return timer_register(timer, msecs);
+}
+
+int uloop_interval_cancel(struct uloop_interval *timer)
+{
+       return timer_remove(timer);
+}
+
+int64_t uloop_interval_remaining(struct uloop_interval *timer)
+{
+       return timer_next(timer);
+}
+
+static void uloop_signal_wake(int signo)
+{
+       uint8_t sigbyte = signo;
+
+       if (signo == SIGCHLD)
+               do_sigchld = true;
+
+       do {
+               if (write(waker_pipe, &sigbyte, 1) < 0) {
+                       if (errno == EINTR)
+                               continue;
+               }
+               break;
+       } while (1);
 }
 
-static void uloop_sigchld(int signo)
+static void uloop_handle_sigint(int signo)
 {
-       do_sigchld = true;
+       uloop_status = signo;
+       uloop_cancelled = true;
+       uloop_signal_wake(signo);
 }
 
 static void uloop_install_handler(int signum, void (*handler)(int), struct sigaction* old, bool add)
@@ -387,35 +540,92 @@ static void uloop_setup_signals(bool add)
 
        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);
+
+       if (uloop_handle_sigchld)
+               uloop_install_handler(SIGCHLD, uloop_signal_wake, &old_sigchld, add);
 
        uloop_ignore_signal(SIGPIPE, add);
 }
 
-static int uloop_get_next_timeout(struct timeval *tv)
+int uloop_signal_add(struct uloop_signal *s)
+{
+       struct list_head *h = &signals;
+       struct uloop_signal *tmp;
+       struct sigaction sa;
+
+       if (s->pending)
+               return -1;
+
+       list_for_each_entry(tmp, &signals, list) {
+               if (tmp->signo > s->signo) {
+                       h = &tmp->list;
+                       break;
+               }
+       }
+
+       list_add_tail(&s->list, h);
+       s->pending = true;
+
+       sigaction(s->signo, NULL, &s->orig);
+
+       if (s->orig.sa_handler != uloop_signal_wake) {
+               sa.sa_handler = uloop_signal_wake;
+               sa.sa_flags = 0;
+               sigemptyset(&sa.sa_mask);
+               sigaction(s->signo, &sa, NULL);
+       }
+
+       return 0;
+}
+
+int uloop_signal_delete(struct uloop_signal *s)
+{
+       if (!s->pending)
+               return -1;
+
+       list_del(&s->list);
+       s->pending = false;
+
+       if (s->orig.sa_handler != uloop_signal_wake)
+               sigaction(s->signo, &s->orig, NULL);
+
+       return 0;
+}
+
+int uloop_get_next_timeout(void)
 {
        struct uloop_timeout *timeout;
-       int diff;
+       struct timeval tv;
+       int64_t diff;
 
        if (list_empty(&timeouts))
                return -1;
 
+       uloop_gettime(&tv);
+
        timeout = list_first_entry(&timeouts, struct uloop_timeout, list);
-       diff = tv_diff(&timeout->time, tv);
+       diff = tv_diff(&timeout->time, &tv);
        if (diff < 0)
                return 0;
+       if (diff > INT_MAX)
+               return INT_MAX;
 
        return diff;
 }
 
-static void uloop_process_timeouts(struct timeval *tv)
+static void uloop_process_timeouts(void)
 {
        struct uloop_timeout *t;
+       struct timeval tv;
 
+       if (list_empty(&timeouts))
+               return;
+
+       uloop_gettime(&tv);
        while (!list_empty(&timeouts)) {
                t = list_first_entry(&timeouts, struct uloop_timeout, list);
 
-               if (tv_diff(&t->time, tv) > 0)
+               if (tv_diff(&t->time, &tv) > 0)
                        break;
 
                uloop_timeout_cancel(t);
@@ -440,23 +650,21 @@ static void uloop_clear_processes(void)
                uloop_process_delete(p);
 }
 
-void uloop_run(void)
+bool uloop_cancelling(void)
 {
-       static int recursive_calls = 0;
-       struct timeval tv;
+       return uloop_run_depth > 0 && uloop_cancelled;
+}
 
-       /*
-        * 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);
+int uloop_run_timeout(int timeout)
+{
+       int next_time = 0;
 
+       uloop_run_depth++;
+
+       uloop_status = 0;
        uloop_cancelled = false;
-       while(!uloop_cancelled)
-       {
-               uloop_gettime(&tv);
-               uloop_process_timeouts(&tv);
+       do {
+               uloop_process_timeouts();
 
                if (do_sigchld)
                        uloop_handle_processes();
@@ -464,21 +672,32 @@ void uloop_run(void)
                if (uloop_cancelled)
                        break;
 
-               uloop_gettime(&tv);
-               uloop_run_events(uloop_get_next_timeout(&tv));
-       }
+               next_time = uloop_get_next_timeout();
+               if (timeout >= 0 && (next_time < 0 || timeout < next_time))
+                               next_time = timeout;
+               uloop_run_events(next_time);
+       } while (!uloop_cancelled && timeout < 0);
 
-       if (!--recursive_calls)
-               uloop_setup_signals(false);
+       --uloop_run_depth;
+
+       return uloop_status;
 }
 
 void uloop_done(void)
 {
-       if (poll_fd < 0)
-               return;
+       uloop_setup_signals(false);
 
-       close(poll_fd);
-       poll_fd = -1;
+       if (poll_fd >= 0) {
+               close(poll_fd);
+               poll_fd = -1;
+       }
+
+       if (waker_pipe >= 0) {
+               uloop_fd_delete(&waker_fd);
+               close(waker_pipe);
+               close(waker_fd.fd);
+               waker_pipe = -1;
+       }
 
        uloop_clear_timeouts();
        uloop_clear_processes();