X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fmodprobe.c;h=d63483481369436f5d639463c7832caa5f9de9a7;hp=90fec711b8120c740d0ac4d48239b68c7db097c4;hb=46440d0ccf65b098757389ffebb0f7452626c4a3;hpb=866c17cef5ab4305d0087cf2823e92f0057904c0

diff --git a/src/bin/lttng-sessiond/modprobe.c b/src/bin/lttng-sessiond/modprobe.c
index 90fec711b..d63483481 100644
--- a/src/bin/lttng-sessiond/modprobe.c
+++ b/src/bin/lttng-sessiond/modprobe.c
@@ -16,6 +16,13 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+/**
+ * @file modprobe.c
+ *
+ * @brief modprobe related functions.
+ *
+ */
+
 #define _LGPL_SOURCE
 #include <assert.h>
 #include <stdio.h>
@@ -27,6 +34,7 @@
 
 #include "modprobe.h"
 #include "kern-modules.h"
+#include "lttng-sessiond.h"
 
 #define LTTNG_MOD_REQUIRED	1
 #define LTTNG_MOD_OPTIONAL	0
@@ -50,6 +58,7 @@ struct kern_modules_param kern_modules_probes_default[] = {
 	{ "lttng-probe-ext3" },
 	{ "lttng-probe-ext4" },
 	{ "lttng-probe-gpio" },
+	{ "lttng-probe-i2c" },
 	{ "lttng-probe-irq" },
 	{ "lttng-probe-jbd" },
 	{ "lttng-probe-jbd2" },
@@ -62,6 +71,7 @@ struct kern_modules_param kern_modules_probes_default[] = {
 	{ "lttng-probe-napi" },
 	{ "lttng-probe-net" },
 	{ "lttng-probe-power" },
+	{ "lttng-probe-preemptirq" },
 	{ "lttng-probe-printk" },
 	{ "lttng-probe-random" },
 	{ "lttng-probe-rcu" },
@@ -93,6 +103,9 @@ static int probes_capacity;
 #if HAVE_KMOD
 #include <libkmod.h>
 
+/**
+ * @brief Logging function for libkmod integration.
+ */
 static void log_kmod(void *data, int priority, const char *file, int line,
 		const char *fn, const char *format, va_list args)
 {
@@ -106,6 +119,15 @@ static void log_kmod(void *data, int priority, const char *file, int line,
 	free(str);
 }
 
+/**
+ * @brief Setup the libkmod context.
+ *
+ * Create the context, add a custom logging function and preload the
+ * ressources for faster operation.
+ *
+ * @returns	\c 0 on success
+ * 		\c < 0 on error
+ */
 static int setup_kmod_ctx(struct kmod_ctx **ctx)
 {
 	int ret = 0;
@@ -128,6 +150,19 @@ error:
 	return ret;
 }
 
+/**
+ * @brief Loads the kernel modules in \p modules
+ *
+ * @param modules	List of modules to load
+ * @param entries	Number of modules in the list
+ * @param required	Are the modules required or optionnal
+ *
+ * If the modules are required, we will return with error after the
+ * first failed module load, otherwise we continue loading.
+ *
+ * @returns		\c 0 on success
+ * 			\c < 0 on error
+ */
 static int modprobe_lttng(struct kern_modules_param *modules,
 		int entries, int required)
 {
@@ -148,9 +183,12 @@ static int modprobe_lttng(struct kern_modules_param *modules,
 			goto error;
 		}
 
-		ret = kmod_module_probe_insert_module(mod, KMOD_PROBE_IGNORE_LOADED,
+		ret = kmod_module_probe_insert_module(mod, 0,
 				NULL, NULL, NULL, NULL);
-		if (ret < 0) {
+		if (ret == -EEXIST) {
+			DBG("Module %s is already loaded", modules[i].name);
+			ret = 0;
+		} else if (ret < 0) {
 			if (required) {
 				ERR("Unable to load required module %s",
 						modules[i].name);
@@ -162,6 +200,7 @@ static int modprobe_lttng(struct kern_modules_param *modules,
 			}
 		} else {
 			DBG("Modprobe successfully %s", modules[i].name);
+			modules[i].loaded = true;
 		}
 
 		kmod_module_unref(mod);
@@ -174,6 +213,18 @@ error:
 	return ret;
 }
 
+/**
+ * @brief Recursively unload modules.
+ *
+ * This function implements the same modules unloading behavior as
+ * 'modprobe -r' or rmmod, it will recursevily go trought the \p module
+ * dependencies and unload modules with a refcount of 0.
+ *
+ * @param mod		The module to unload
+ *
+ * @returns		\c 0 on success
+ * 			\c < 0 on error
+ */
 static int rmmod_recurse(struct kmod_module *mod) {
 	int ret = 0;
 	struct kmod_list *deps, *itr;
@@ -202,6 +253,14 @@ static int rmmod_recurse(struct kmod_module *mod) {
 	return ret;
 }
 
+/**
+ * @brief Unloads the kernel modules in \p modules
+ *
+ * @param modules	List of modules to unload
+ * @param entries	Number of modules in the list
+ * @param required	Are the modules required or optionnal
+ *
+ */
 static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 		int entries, int required)
 {
@@ -216,6 +275,10 @@ static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 	for (i = entries - 1; i >= 0; i--) {
 		struct kmod_module *mod = NULL;
 
+		if (!modules[i].loaded) {
+			continue;
+		}
+
 		ret = kmod_module_new_from_name(ctx, modules[i].name, &mod);
 		if (ret < 0) {
 			PERROR("Failed to create kmod module for %s", modules[i].name);
@@ -282,6 +345,7 @@ static int modprobe_lttng(struct kern_modules_param *modules,
 			}
 		} else {
 			DBG("Modprobe successfully %s", modules[i].name);
+			modules[i].loaded = true;
 		}
 	}
 
@@ -296,6 +360,9 @@ static void modprobe_remove_lttng(const struct kern_modules_param *modules,
 	char modprobe[256];
 
 	for (i = entries - 1; i >= 0; i--) {
+		if (!modules[i].loaded) {
+			continue;
+		}
 		ret = snprintf(modprobe, sizeof(modprobe),
 				"/sbin/modprobe -r -q %s",
 				modules[i].name);
@@ -503,12 +570,7 @@ int modprobe_lttng_data(void)
 	 * Base probes: either from command line option, environment
 	 * variable or default list.
 	 */
-	if (kmod_probes_list) {
-		list = kmod_probes_list;
-	} else {
-		list = utils_get_kmod_probes_list();
-	}
-
+	list = config.kmod_probes_list.value;
 	if (list) {
 		/* User-specified probes. */
 		ret = append_list_to_probes(list);
@@ -543,12 +605,7 @@ int modprobe_lttng_data(void)
 	/*
 	 * Extra modules? Append them to current probes list.
 	 */
-	if (kmod_extra_probes_list) {
-		list = kmod_extra_probes_list;
-	} else {
-		list = utils_get_extra_kmod_probes_list();
-	}
-
+	list = config.kmod_extra_probes_list.value;
 	if (list) {
 		ret = append_list_to_probes(list);
 		if (ret) {