+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)
+{
+ char *str;
+
+ if (vasprintf(&str, format, args) < 0) {
+ return;
+ }
+
+ DBG("libkmod: %s", str);
+ 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;
+
+ *ctx = kmod_new(NULL, NULL);
+ if (!ctx) {
+ PERROR("Unable to create kmod library context");
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ kmod_set_log_fn(*ctx, log_kmod, NULL);
+ ret = kmod_load_resources(*ctx);
+ if (ret < 0) {
+ ERR("Failed to load kmod library resources");
+ goto error;
+ }
+
+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)
+{
+ int ret = 0, i;
+ struct kmod_ctx *ctx;
+
+ ret = setup_kmod_ctx(&ctx);
+ if (ret < 0) {
+ goto error;
+ }
+
+ for (i = 0; i < entries; i++) {
+ struct kmod_module *mod = NULL;
+
+ 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);
+ goto error;
+ }
+
+ ret = kmod_module_probe_insert_module(mod, 0,
+ NULL, NULL, NULL, NULL);
+ 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);
+ goto error;
+ } else {
+ DBG("Unable to load optional module %s; continuing",
+ modules[i].name);
+ ret = 0;
+ }
+ } else {
+ DBG("Modprobe successfully %s", modules[i].name);
+ modules[i].loaded = true;
+ }
+
+ kmod_module_unref(mod);
+ }
+
+error:
+ if (ctx) {
+ kmod_unref(ctx);
+ }
+ 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;
+
+ if (kmod_module_get_initstate(mod) == KMOD_MODULE_BUILTIN) {
+ DBG("Module %s is builtin", kmod_module_get_name(mod));
+ return ret;
+ }
+
+ ret = kmod_module_remove_module(mod, 0);
+
+ deps = kmod_module_get_dependencies(mod);
+ if (deps != NULL) {
+ kmod_list_foreach(itr, deps) {
+ struct kmod_module *dep = kmod_module_get_module(itr);
+ if (kmod_module_get_refcnt(dep) == 0) {
+ DBG("Recursive remove module %s",
+ kmod_module_get_name(dep));
+ rmmod_recurse(dep);
+ }
+ kmod_module_unref(dep);
+ }
+ kmod_module_unref_list(deps);
+ }
+
+ 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)
+{
+ int ret = 0, i;
+ struct kmod_ctx *ctx;
+
+ ret = setup_kmod_ctx(&ctx);
+ if (ret < 0) {
+ goto error;
+ }
+
+ 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);
+ goto error;
+ }
+
+ ret = rmmod_recurse(mod);
+ if (ret == -EEXIST) {
+ DBG("Module %s is not in kernel.", modules[i].name);
+ } else if (required && ret < 0) {
+ ERR("Unable to remove module %s", modules[i].name);
+ } else {
+ DBG("Modprobe removal successful %s",
+ modules[i].name);
+ }
+
+ kmod_module_unref(mod);
+ }
+
+error:
+ if (ctx) {
+ kmod_unref(ctx);
+ }
+}
+
+#else /* HAVE_KMOD */
+
+static int modprobe_lttng(struct kern_modules_param *modules,
+ int entries, int required)
+{
+ int ret = 0, i;
+ char modprobe[256];
+
+ for (i = 0; i < entries; i++) {
+ ret = snprintf(modprobe, sizeof(modprobe),
+ "/sbin/modprobe %s%s",
+ required ? "" : "-q ",
+ modules[i].name);
+ if (ret < 0) {
+ PERROR("snprintf modprobe");
+ goto error;
+ }
+ modprobe[sizeof(modprobe) - 1] = '\0';
+ ret = system(modprobe);
+ if (ret == -1) {
+ if (required) {
+ ERR("Unable to launch modprobe for required module %s",
+ modules[i].name);
+ goto error;
+ } else {
+ DBG("Unable to launch modprobe for optional module %s; continuing",
+ modules[i].name);
+ ret = 0;
+ }
+ } else if (WEXITSTATUS(ret) != 0) {
+ if (required) {
+ ERR("Unable to load required module %s",
+ modules[i].name);
+ goto error;
+ } else {
+ DBG("Unable to load optional module %s; continuing",
+ modules[i].name);
+ ret = 0;
+ }
+ } else {
+ DBG("Modprobe successfully %s", modules[i].name);
+ modules[i].loaded = true;
+ }
+ }