#undef LOCAL_DEBUG
#include "ucw/lib.h"
+#include "ucw/heap.h"
#include "ucw/mainloop.h"
#include <stdio.h>
timestamp_t main_idle_time;
uns main_shutdown;
-clist main_timer_list, main_file_list, main_hook_list, main_process_list;
+#define GBUF_PREFIX(x) main_timer_table_##x
+#define GBUF_TYPE struct main_timer *
+#include "ucw/gbuf.h"
+static uns main_timer_cnt;
+static main_timer_table_t main_timer_table;
+#define MAIN_TIMER_LESS(x,y) ((x)->expires < (y)->expires)
+#define MAIN_TIMER_SWAP(heap,a,b,t) (t=heap[a], heap[a]=heap[b], heap[b]=t, heap[a]->index=(a), heap[b]->index=(b))
+
+clist main_file_list, main_hook_list, main_hook_done_list, main_process_list;
static uns main_file_cnt;
static uns main_poll_table_obsolete, main_poll_table_size;
static struct pollfd *main_poll_table;
static uns main_sigchld_set_up;
+static volatile sig_atomic_t chld_received = 0;
+
+#ifdef O_CLOEXEC
+// On recent Linux systems, O_CLOEXEC flag is available and we can get around
+// the race condition of poll().
+#define USE_SELF_PIPE
+static int sig_pipe_recv, sig_pipe_send;
+#endif
void
main_get_time(void)
main_init(void)
{
DBG("MAIN: Initializing");
- clist_init(&main_timer_list);
+ main_timer_cnt = 0;
clist_init(&main_file_list);
clist_init(&main_hook_list);
+ clist_init(&main_hook_done_list);
clist_init(&main_process_list);
main_file_cnt = 0;
main_poll_table_obsolete = 1;
DBG("MAIN: Setting timer %p (expire at now+%lld)", tm, (long long)(expires-main_now));
else
DBG("MAIN: Clearing timer %p", tm);
- if (tm->expires)
- clist_remove(&tm->n);
- tm->expires = expires;
- if (expires)
+ if (tm->expires < expires)
+ {
+ if (!tm->expires)
+ {
+ tm->expires = expires;
+ tm->index = ++main_timer_cnt;
+ main_timer_table_grow(&main_timer_table, tm->index + 1);
+ main_timer_table.ptr[tm->index] = tm;
+ HEAP_INSERT(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP);
+ }
+ else
+ {
+ tm->expires = expires;
+ HEAP_INCREASE(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
+ }
+ }
+ else if (tm->expires > expires)
{
- cnode *t = main_timer_list.head.next;
- while (t != &main_timer_list.head && ((struct main_timer *) t)->expires < expires)
- t = t->next;
- clist_insert_before(&tm->n, t);
+ if (!expires)
+ {
+ ASSERT(tm->index && tm->index <= main_timer_cnt);
+ HEAP_DELETE(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
+ tm->index = 0;
+ tm->expires = 0;
+ }
+ else
+ {
+ tm->expires = expires;
+ HEAP_DECREASE(struct main_timer *, main_timer_table.ptr, main_timer_cnt, MAIN_TIMER_LESS, MAIN_TIMER_SWAP, tm->index);
+ }
}
}
ho->n.next = ho->n.prev = NULL;
}
+#ifdef USE_SELF_PIPE
+static void
+main_sigchld_handler(int x UNUSED)
+{
+ int old_errno = errno;
+ DBG("SIGCHLD received");
+ chld_received = 1;
+ ssize_t result;
+ while((result = write(sig_pipe_send, "c", 1)) == -1 && errno == EINTR);
+ if(result == -1 && errno != EAGAIN)
+ msg(L_SIGHANDLER|L_ERROR, "Could not write to self-pipe: %m");
+ errno = old_errno;
+}
+
+static int
+dummy_read_handler(struct main_file *mp)
+{
+ char buffer[1024];
+ ssize_t result = read(mp->fd, buffer, 1024);
+ if(result == -1 && errno != EAGAIN)
+ msg(L_ERROR, "Could not read from selfpipe: %m");
+ file_chg(mp);
+ return result == 1024;
+}
+
+static void
+pipe_configure(int fd)
+{
+ int flags;
+ if((flags = fcntl(fd, F_GETFL)) == -1 || fcntl(fd, F_SETFL, flags|O_NONBLOCK))
+ die("Could not set file descriptor %d to non-blocking: %m", fd);
+ if((flags = fcntl(fd, F_GETFD)) == -1 || fcntl(fd, F_SETFD, flags|O_CLOEXEC))
+ die("Could not set file descriptor %d to close-on-exec: %m", fd);
+}
+#else
static void
main_sigchld_handler(int x UNUSED)
{
DBG("SIGCHLD received");
}
+#endif
void
process_add(struct main_process *mp)
clist_add_tail(&main_process_list, &mp->n);
if (!main_sigchld_set_up)
{
+#ifdef USE_SELF_PIPE
+ int pipe_result[2];
+ if(pipe(pipe_result) == -1)
+ die("Could not create selfpipe:%m");
+ pipe_configure(pipe_result[0]);
+ pipe_configure(pipe_result[1]);
+ sig_pipe_recv = pipe_result[0];
+ sig_pipe_send = pipe_result[1];
+ static struct main_file self_pipe;
+ self_pipe = (struct main_file) {
+ .fd = sig_pipe_recv,
+ .read_handler = dummy_read_handler
+ };
+ file_add(&self_pipe);
+#endif
struct sigaction sa;
bzero(&sa, sizeof(sa));
sa.sa_handler = main_sigchld_handler;
sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
sigaction(SIGCHLD, &sa, NULL);
main_sigchld_set_up = 1;
+ chld_received = 1; // The signal may have come before the handler
}
}
#ifdef CONFIG_DEBUG
msg(L_DEBUG, "### Main loop status on %lld", (long long)main_now);
msg(L_DEBUG, "\tActive timers:");
- struct main_timer *tm;
- CLIST_WALK(tm, main_timer_list)
- msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires-main_now : 999999), tm->data);
+ for (uns i = 1; i <= main_timer_cnt; i++)
+ {
+ struct main_timer *tm = main_timer_table.ptr[i];
+ msg(L_DEBUG, "\t\t%p (expires %lld, data %p)", tm, (long long)(tm->expires ? tm->expires-main_now : 999999), tm->data);
+ }
struct main_file *fi;
msg(L_DEBUG, "\tActive files:");
CLIST_WALK(fi, main_file_list)
(long long)(fi->timer.expires ? fi->timer.expires-main_now : 999999), fi->data);
msg(L_DEBUG, "\tActive hooks:");
struct main_hook *ho;
+ CLIST_WALK(ho, main_hook_done_list)
+ msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
CLIST_WALK(ho, main_hook_list)
msg(L_DEBUG, "\t\t%p (func %p, data %p)", ho, ho->handler, ho->data);
msg(L_DEBUG, "\tActive processes:");
main_loop(void)
{
DBG("MAIN: Entering main_loop");
- ASSERT(main_timer_list.head.next);
+ ASSERT(main_hook_list.head.next);
struct main_file *fi;
struct main_hook *ho;
struct main_timer *tm;
struct main_process *pr;
- cnode *tmp;
main_get_time();
for (;;)
{
timestamp_t wake = main_now + 1000000000;
- while ((tm = clist_head(&main_timer_list)) && tm->expires <= main_now)
+ while (main_timer_cnt && (tm = main_timer_table.ptr[1])->expires <= main_now)
{
DBG("MAIN: Timer %p expired at now-%lld", tm, (long long)(main_now - tm->expires));
tm->handler(tm);
}
int hook_min = HOOK_RETRY;
int hook_max = HOOK_SHUTDOWN;
- CLIST_WALK_DELSAFE(ho, main_hook_list, tmp)
+ while (ho = clist_remove_head(&main_hook_list))
{
+ clist_add_tail(&main_hook_done_list, &ho->n);
DBG("MAIN: Hook %p", ho);
int ret = ho->handler(ho);
hook_min = MIN(hook_min, ret);
hook_max = MAX(hook_max, ret);
}
+ clist_move(&main_hook_list, &main_hook_done_list);
if (hook_min == HOOK_SHUTDOWN ||
hook_min == HOOK_DONE && hook_max == HOOK_DONE ||
main_shutdown)
wake = 0;
if (main_poll_table_obsolete)
main_rebuild_poll_table();
- if (!clist_empty(&main_process_list))
+#ifndef USE_SELF_PIPE
+ // We don't have a reliable flag without the self-pipe.
+ chld_received = 1;
+#endif
+ if (chld_received && !clist_empty(&main_process_list))
{
int stat;
pid_t pid;
wake = MIN(wake, main_now + 10000);
+ chld_received = 0;
while ((pid = waitpid(-1, &stat, WNOHANG)) > 0)
{
DBG("MAIN: Child %d exited with status %x", pid, stat);
wake = 0;
}
}
- /* FIXME: Here is a small race window where SIGCHLD can come unnoticed. */
- if ((tm = clist_head(&main_timer_list)) && tm->expires < wake)
+ if (main_timer_cnt && (tm = main_timer_table.ptr[1])->expires < wake)
wake = tm->expires;
main_get_time();
- int timeout = (wake ? wake - main_now : 0);
+ int timeout = ((wake > main_now) ? wake - main_now : 0);
DBG("MAIN: Poll for %d fds and timeout %d ms", main_file_cnt, timeout);
int p = poll(main_poll_table, main_file_cnt, timeout);
timestamp_t old_now = main_now;
projects / libucw.git / blobdiff