xenconsoled: replace gettimeofday with clock_gettime

Currently if someone changes the date on the host, xenconsoled may
behave incorrectly due to the use of gettimeofday for the rate control
algorithm. For example I was able to hang the console connected to a
guest just setting the date forward 20 years. To solve the problem we
need to use a time source that doesn't change start point, that is
clock_gettime with CLOCK_MONOTONIC. The only bad side effect is that
it introduces a dependency to librt, but I think is well worth it.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

diff --git a/tools/console/Makefile b/tools/console/Makefile
index 3d7e0fe307205720aeedb68718ac026fde52aa26..10e909a0b621572096317c02c6afaae3b76dc3f3 100644 (file)
--- a/tools/console/Makefile
+++ b/tools/console/Makefile
@@ -21,7 +21,7 @@ clean:
 
 xenconsoled: $(patsubst %.c,%.o,$(wildcard daemon/*.c))
        $(CC) $(CFLAGS) $^ -o $@ $(LDFLAGS) \
-              $(UTIL_LIBS) $(SOCKET_LIBS)
+              $(UTIL_LIBS) $(SOCKET_LIBS) -lrt
 
 xenconsole: $(patsubst %.c,%.o,$(wildcard client/*.c))
        $(CC) $(CFLAGS) $^ -o $@ $(LDFLAGS) \

diff --git a/tools/console/daemon/io.c b/tools/console/daemon/io.c
index 16a0b6c27eada1178b341f08e8d4226685f94e24..78aea83ed7d596f2c07e3c4a2ab772a6c44b50ed 100644 (file)
--- a/tools/console/daemon/io.c
+++ b/tools/console/daemon/io.c
@@ -622,9 +622,9 @@ static struct domain *create_domain(int domid)
 {
        struct domain *dom;
        char *s;
-       struct timeval tv;
+       struct timespec ts;
 
-       if (gettimeofday(&tv, NULL) < 0) {
+       if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
                dolog(LOG_ERR, "Cannot get time of day %s:%s:L%d",
                      __FILE__, __FUNCTION__, __LINE__);
                return NULL;
@@ -666,7 +666,7 @@ static struct domain *create_domain(int domid)
        dom->buffer.capacity = 0;
        dom->buffer.max_capacity = 0;
        dom->event_count = 0;
-       dom->next_period = (tv.tv_sec * 1000) + (tv.tv_usec / 1000) + RATE_LIMIT_PERIOD;
+       dom->next_period = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000) + RATE_LIMIT_PERIOD;
        dom->next = NULL;
 
        dom->ring_ref = -1;
@@ -971,7 +971,7 @@ void handle_io(void)
                struct domain *d, *n;
                int max_fd = -1;
                struct timeval timeout;
-               struct timeval tv;
+               struct timespec ts;
                long long now, next_timeout = 0;
 
                FD_ZERO(&readfds);
@@ -985,9 +985,9 @@ void handle_io(void)
                        max_fd = MAX(xc_evtchn_fd(xce_handle), max_fd);
                }
 
-               if (gettimeofday(&tv, NULL) < 0)
+               if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0)
                        return;
-               now = (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
+               now = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000);
 
                /* Re-calculate any event counter allowances & unblock
                   domains with new allowance */