base: Clean up signal handling

The PollEvent class dynamically installs a SIGIO and SIGALRM handler
when a file handler is registered. Most signal handlers currently get
registered in the initSignals() function. This changeset moves the
SIGIO/SIGALRM handlers to initSignals() to live with the other signal
handlers. The original code installs SIGIO and SIGALRM with the
SA_RESTART option to prevent syscalls from returning EINTR. This
changeset consistently uses this flag for all signal handlers to
ensure that other signals that trigger asynchronous behavior (e.g.,
statistics dumping) do not cause undesirable EINTR returns.

2 files changed, 0 insertions, 71 deletions

diff --git a/src/base/pollevent.cc b/src/base/pollevent.cc
index cb44d8728..67e97f98f 100644
--- a/src/base/pollevent.cc
+++ b/src/base/pollevent.cc
@@ -109,7 +109,6 @@ PollQueue::PollQueue()
 
 PollQueue::~PollQueue()
 {
-    removeHandler();
     for (int i = 0; i < num_fds; i++)
         setupAsyncIO(poll_fds[0].fd, false);
 
@@ -170,7 +169,6 @@ PollQueue::schedule(PollEvent *event)
             max_size *= 2;
         } else {
             max_size = 16;
-            setupHandler();
         }
 
         poll_fds = new pollfd[max_size];
@@ -197,10 +195,6 @@ PollQueue::service()
     }
 }
 
-struct sigaction PollQueue::oldio;
-struct sigaction PollQueue::oldalrm;
-bool PollQueue::handler = false;
-
 void
 PollQueue::setupAsyncIO(int fd, bool set)
 {
@@ -221,59 +215,3 @@ PollQueue::setupAsyncIO(int fd, bool set)
     if (fcntl(fd, F_SETFL, flags) == -1)
         panic("Could not set up async IO");
 }
-
-void
-PollQueue::setupHandler()
-{
-    struct sigaction act;
-
-    act.sa_handler = handleIO;
-    sigemptyset(&act.sa_mask);
-    act.sa_flags = SA_RESTART;
-
-    if (sigaction(SIGIO, &act, &oldio) == -1)
-        panic("could not do sigaction");
-
-    act.sa_handler = handleALRM;
-    sigemptyset(&act.sa_mask);
-    act.sa_flags = SA_RESTART;
-
-    if (sigaction(SIGALRM, &act, &oldalrm) == -1)
-        panic("could not do sigaction");
-
-    alarm(1);
-
-    handler = true;
-}
-
-void
-PollQueue::removeHandler()
-{
-    if (sigaction(SIGIO, &oldio, NULL) == -1)
-        panic("could not remove handler");
-
-    if (sigaction(SIGIO, &oldalrm, NULL) == -1)
-        panic("could not remove handler");
-}
-
-void
-PollQueue::handleIO(int sig)
-{
-    if (sig != SIGIO)
-        panic("Wrong Handler");
-
-    async_event = true;
-    async_io = true;
-}
-
-void
-PollQueue::handleALRM(int sig)
-{
-    if (sig != SIGALRM)
-        panic("Wrong Handler");
-
-    async_event = true;
-    async_alarm = true;
-    alarm(1);
-}
-
diff --git a/src/base/pollevent.hh b/src/base/pollevent.hh
index b9c833c8a..5e0faa729 100644
--- a/src/base/pollevent.hh
+++ b/src/base/pollevent.hh
@@ -83,17 +83,8 @@ class PollQueue
     void schedule(PollEvent *event);
     void service();
 
-  protected:
-    static bool handler;
-    static struct sigaction oldio;
-    static struct sigaction oldalrm;
-
   public:
     static void setupAsyncIO(int fd, bool set);
-    static void handleIO(int);
-    static void handleALRM(int);
-    static void removeHandler();
-    static void setupHandler();
 };
 
 extern PollQueue pollQueue;