From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Fri, 5 Aug 2011 20:28:01 +0000 (-0400)
Subject: Unload lttng modules when sessiond quits
X-Git-Tag: v2.0-pre7~7
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=ab14718513c62c38a882d103b1dc727467271ff7;p=lttng-tools.git

Unload lttng modules when sessiond quits

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/ltt-sessiond/ltt-sessiond.h b/ltt-sessiond/ltt-sessiond.h
index 17c9c32f8..0882d40a8 100644
--- a/ltt-sessiond/ltt-sessiond.h
+++ b/ltt-sessiond/ltt-sessiond.h
@@ -19,32 +19,38 @@
 #ifndef _LTT_SESSIOND_H
 #define _LTT_SESSIOND_H
 
-#define DEFAULT_HOME_DIR			"/tmp"
+#define DEFAULT_HOME_DIR		"/tmp"
 #define DEFAULT_UST_SOCK_DIR		DEFAULT_HOME_DIR "/ust-app-socks"
 #define DEFAULT_GLOBAL_APPS_PIPE	DEFAULT_UST_SOCK_DIR "/global"
-#define DEFAULT_TRACE_OUTPUT        DEFAULT_HOME_DIR "/lttng"
+#define DEFAULT_TRACE_OUTPUT        	DEFAULT_HOME_DIR "/lttng"
+
+struct module_param {
+	const char *name;
+	int required;
+};
 
 /* LTTng kernel tracer modules list */
-const char *kernel_modules_list[] = {
-	"lib-ring-buffer",
-	"ltt-relay",
-	"ltt-ring-buffer-client-discard",
-	"ltt-ring-buffer-client-overwrite",
-	"ltt-ring-buffer-metadata-client",
-	"ltt-ring-buffer-client-mmap-discard",
-	"ltt-ring-buffer-client-mmap-overwrite",
-	"ltt-ring-buffer-metadata-mmap-client",
-	"lttng-ftrace",
-	"lttng-kprobes",
-	"lttng-kretprobes",
-	"lttng-probe-block",
-	"lttng-probe-irq",
-	"lttng-probe-kvm",
-	"lttng-probe-lttng",
-	"lttng-probe-sched",
-	"lttng-probe-syscalls",
-	"lttng-types",
-	NULL,
+const struct module_param kernel_modules_list[] = {
+	/* used by ltt-relay, unload last */
+	{ "lttng-ftrace", 0 },
+	{ "lttng-kprobes", 0 },
+	{ "lttng-kretprobes", 0 },
+
+	{ "lib-ring-buffer", 1 },
+	{ "ltt-relay", 1 },
+	{ "ltt-ring-buffer-client-discard", 1 },
+	{ "ltt-ring-buffer-client-overwrite", 1 },
+	{ "ltt-ring-buffer-metadata-client", 1 },
+	{ "ltt-ring-buffer-client-mmap-discard", 1 },
+	{ "ltt-ring-buffer-client-mmap-overwrite", 1 },
+	{ "ltt-ring-buffer-metadata-mmap-client", 1 },
+	{ "lttng-probe-lttng", 1 },
+	{ "lttng-types", 0 },
+	{ "lttng-probe-block", 0 },
+	{ "lttng-probe-irq", 0 },
+	{ "lttng-probe-kvm", 0 },
+	{ "lttng-probe-sched", 0 },
+	{ "lttng-probe-syscalls", 0 },
 };
 
 extern const char default_home_dir[],
diff --git a/ltt-sessiond/main.c b/ltt-sessiond/main.c
index cb8b98c7b..b3dc0e3a6 100644
--- a/ltt-sessiond/main.c
+++ b/ltt-sessiond/main.c
@@ -99,6 +99,8 @@ static sem_t kconsumerd_sem;
 
 static pthread_mutex_t kconsumerd_pid_mutex;	/* Mutex to control kconsumerd pid assignation */
 
+static int modprobe_remove_kernel_modules(void);
+
 /*
  * Pointer initialized before thread creation.
  *
@@ -195,6 +197,9 @@ static void cleanup()
 
 	DBG("Closing kernel fd");
 	close(kernel_tracer_fd);
+
+	DBG("Unloading kernel modules");
+	modprobe_remove_kernel_modules();
 }
 
 /*
@@ -944,22 +949,67 @@ error:
  */
 static int modprobe_kernel_modules(void)
 {
-	int ret = 0, i = 0;
+	int ret = 0, i;
 	char modprobe[256];
 
-	while (kernel_modules_list[i] != NULL) {
-		ret = snprintf(modprobe, sizeof(modprobe), "/sbin/modprobe %s",
-				kernel_modules_list[i]);
+	for (i = 0; i < ARRAY_SIZE(kernel_modules_list); i++) {
+		ret = snprintf(modprobe, sizeof(modprobe),
+			"/sbin/modprobe %s%s",
+			kernel_modules_list[i].required ? "" : "--quiet ",
+			kernel_modules_list[i].name);
 		if (ret < 0) {
 			perror("snprintf modprobe");
 			goto error;
 		}
+		modprobe[sizeof(modprobe) - 1] = '\0';
 		ret = system(modprobe);
+		if (ret == -1) {
+			ERR("Unable to launch modprobe for module %s",
+				kernel_modules_list[i].name);
+		} else if (kernel_modules_list[i].required
+			   && WEXITSTATUS(ret) != 0) {
+			ERR("Unable to load module %s",
+				kernel_modules_list[i].name);
+		} else {
+			DBG("Modprobe successfully %s",
+				kernel_modules_list[i].name);
+		}
+	}
+
+error:
+	return ret;
+}
+
+/*
+ * modprobe_remove_kernel_modules
+ * Remove modules in reverse load order.
+ */
+static int modprobe_remove_kernel_modules(void)
+{
+	int ret = 0, i;
+	char modprobe[256];
+
+	for (i = ARRAY_SIZE(kernel_modules_list) - 1; i >= 0; i--) {
+		ret = snprintf(modprobe, sizeof(modprobe),
+			"/sbin/modprobe --remove --quiet %s",
+			kernel_modules_list[i].name);
 		if (ret < 0) {
-			ERR("Unable to load module %s", kernel_modules_list[i]);
+			perror("snprintf modprobe --remove");
+			goto error;
+		}
+		modprobe[sizeof(modprobe) - 1] = '\0';
+		ret = system(modprobe);
+		if (ret == -1) {
+			ERR("Unable to launch modprobe --remove for module %s",
+				kernel_modules_list[i].name);
+		} else if (kernel_modules_list[i].required
+			   && WEXITSTATUS(ret) != 0) {
+			ERR("Unable to remove module %s",
+				kernel_modules_list[i].name);
+		} else {
+			DBG("Modprobe removal successful %s",
+				kernel_modules_list[i].name);
 		}
-		DBG("Modprobe successfully %s", kernel_modules_list[i]);
-		i++;
 	}
 
 error:
diff --git a/ltt-sessiond/utils.h b/ltt-sessiond/utils.h
index 9770b2ca6..d451eb63a 100644
--- a/ltt-sessiond/utils.h
+++ b/ltt-sessiond/utils.h
@@ -19,6 +19,10 @@
 #ifndef _LTT_UTILS_H
 #define _LTT_UTILS_H
 
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(array)	(sizeof(array) / (sizeof((array)[0])))
+#endif
+
 int mkdir_recursive(const char *path, mode_t mode);
 const char *get_home_dir(void);