X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libust%2Ftracectl.c;h=7a5cf9562282ce7fe90cc3d5e4c405d3bf44b8c6;hb=f51d84eac11907346fa02e33da358aad171ac80a;hp=74ad4ea6be59a309ab8a4634ae7af15d48725d2b;hpb=8649cd59b1c15b8d4097cf63f733e8007d76ad13;p=ust.git

diff --git a/libust/tracectl.c b/libust/tracectl.c
index 74ad4ea..7a5cf95 100644
--- a/libust/tracectl.c
+++ b/libust/tracectl.c
@@ -19,6 +19,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <pthread.h>
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -456,18 +457,18 @@ static int do_cmd_get_subbuf_size(const char *recvbuf, struct ustcomm_source *sr
 	return retval;
 }
 
-static unsigned int poweroftwo(unsigned int x)
-{
-    unsigned int power2 = 1;
-    unsigned int hardcoded = 2147483648; /* FIX max 2^31 */
-
-    if (x < 2)
-        return 2;
-
-    while (power2 < x && power2 < hardcoded)
-        power2 *= 2;
+/* Return the power of two which is equal or higher to v */
 
-    return power2;
+static unsigned int pow2_higher_or_eq(unsigned int v)
+{
+	int hb = fls(v);
+	int hbm1 = hb-1;
+	int retval = 1<<(hb-1);
+
+	if(v-retval == 0)
+		return retval;
+	else
+		return retval<<1;
 }
 
 static int do_cmd_set_subbuf_size(const char *recvbuf, struct ustcomm_source *src)
@@ -491,9 +492,10 @@ static int do_cmd_set_subbuf_size(const char *recvbuf, struct ustcomm_source *sr
 		goto end;
 	}
 
-	power = poweroftwo(size);
+	power = pow2_higher_or_eq(size);
+	power = max_t(unsigned int, 2u, power);
 	if (power != size)
-		WARN("using the next 2^n = %u\n", power);
+		WARN("using the next power of two for buffer size = %u\n", power);
 
 	ltt_lock_traces();
 	trace = _ltt_trace_find_setup(trace_name);
@@ -1030,17 +1032,38 @@ static pthread_t listener_thread;
 void create_listener(void)
 {
 	int result;
+	sigset_t sig_all_blocked;
+	sigset_t orig_parent_mask;
 
 	if(have_listener) {
 		WARN("not creating listener because we already had one");
 		return;
 	}
 
+	/* A new thread created by pthread_create inherits the signal mask
+	 * from the parent. To avoid any signal being received by the
+	 * listener thread, we block all signals temporarily in the parent,
+	 * while we create the listener thread.
+	 */
+
+	sigfillset(&sig_all_blocked);
+
+	result = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
+	if(result) {
+		PERROR("pthread_sigmask: %s", strerror(result));
+	}
+
 	result = pthread_create(&listener_thread, NULL, listener_main, NULL);
 	if(result == -1) {
 		PERROR("pthread_create");
 	}
 
+	/* Restore original signal mask in parent */
+	result = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
+	if(result) {
+		PERROR("pthread_sigmask: %s", strerror(result));
+	}
+
 	have_listener = 1;
 }