Fix: syscall tracing: missing trigger actions
[lttng-modules.git] / src / lttng-syscalls.c
index 9481d4ff8a4b21808d01c790075af6a16f5fa009..d618bd33ae02474338608cc429dcb06dd461c004 100644 (file)
@@ -130,10 +130,16 @@ struct lttng_syscall_filter {
        DECLARE_BITMAP(sc_exit, NR_syscalls);
        DECLARE_BITMAP(sc_compat_entry, NR_compat_syscalls);
        DECLARE_BITMAP(sc_compat_exit, NR_compat_syscalls);
-};
 
-static
-int lttng_syscalls_create_matching_event_notifiers(struct lttng_event_enabler_common *event_enabler);
+       /*
+        * Reference counters keeping track of number of events enabled
+        * for each bit.
+        */
+       u32 sc_entry_refcount_map[NR_syscalls];
+       u32 sc_exit_refcount_map[NR_syscalls];
+       u32 sc_compat_entry_refcount_map[NR_compat_syscalls];
+       u32 sc_compat_exit_refcount_map[NR_compat_syscalls];
+};
 
 static void syscall_entry_event_unknown(struct hlist_head *unknown_action_list_head,
        struct pt_regs *regs, long id)
@@ -571,14 +577,15 @@ void lttng_syscall_event_enabler_create_event(struct lttng_event_enabler_common
                if (!event_recorder_enabler)
                        return;
                event = _lttng_kernel_event_create(&event_recorder_enabler->parent, desc);
-               WARN_ON_ONCE(!event || IS_ERR(event));
+               WARN_ON_ONCE(IS_ERR(event));
                lttng_event_enabler_destroy(&event_recorder_enabler->parent);
-               if (!event || IS_ERR(event)) {
+               if (IS_ERR(event)) {
                        printk(KERN_INFO "Unable to create event recorder %s\n", desc->event_name);
                        return;
                }
+               event->priv->u.syscall.syscall_id = syscall_nr;
                if (dispatch_table)
-                       hlist_add_head_rcu(&event->priv->u.syscall.node, &dispatch_table[syscall_nr]);
+                       hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_table);
                break;
        }
        case LTTNG_EVENT_ENABLER_TYPE_NOTIFIER:
@@ -620,9 +627,9 @@ void lttng_syscall_event_enabler_create_event(struct lttng_event_enabler_common
                                &event_notifier_param, syscall_event_notifier_enabler->group);
                WARN_ON_ONCE(!event_notifier_enabler);
                event = _lttng_kernel_event_create(&event_notifier_enabler->parent, desc);
-               WARN_ON_ONCE(!event || IS_ERR(event));
+               WARN_ON_ONCE(IS_ERR(event));
                lttng_event_enabler_destroy(&event_notifier_enabler->parent);
-               if (!event || IS_ERR(event)) {
+               if (IS_ERR(event)) {
                        printk(KERN_INFO "Unable to create event notifier %s\n", desc->event_name);
                        return;
                }
@@ -637,21 +644,22 @@ void lttng_syscall_event_enabler_create_event(struct lttng_event_enabler_common
 }
 
 static
-void lttng_syscall_event_enabler_create_matching_events(struct lttng_event_enabler_common *syscall_event_enabler_common,
-               const struct trace_syscall_entry *table,
-               size_t table_len,
-               struct hlist_head *dispatch_table,
-               enum sc_type type)
+void lttng_syscall_event_enabler_create_matching_syscall_table_events(struct lttng_event_enabler_common *syscall_event_enabler_common,
+               const struct trace_syscall_entry *table, size_t table_len, enum sc_type type)
 {
        struct lttng_event_ht *events_ht = lttng_get_event_ht_from_enabler(syscall_event_enabler_common);
        const struct lttng_kernel_event_desc *desc;
        unsigned int i;
 
-       /* iterate over all syscall and create event_notifier that match */
+#ifndef CONFIG_COMPAT
+       if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
+               return;
+#endif
+       /* iterate over all syscall and create event that match */
        for (i = 0; i < table_len; i++) {
                struct lttng_kernel_event_common_private *event_priv;
                struct hlist_head *head;
-               int found = 0;
+               bool found = false;
 
                desc = table[i].desc;
                if (!desc) {
@@ -667,16 +675,32 @@ void lttng_syscall_event_enabler_create_matching_events(struct lttng_event_enabl
                 */
                head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
                lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
-                       if (lttng_event_enabler_desc_match_event(syscall_event_enabler_common, desc, event_priv->pub))
-                               found = 1;
+                       if (lttng_event_enabler_desc_match_event(syscall_event_enabler_common, desc, event_priv->pub)) {
+                               found = true;
+                               break;
+                       }
                }
                if (found)
                        continue;
 
-               lttng_syscall_event_enabler_create_event(syscall_event_enabler_common, desc, dispatch_table, type, i);
+               lttng_syscall_event_enabler_create_event(syscall_event_enabler_common, desc, NULL, type, i);
        }
 }
 
+static
+bool lttng_syscall_event_enabler_is_wildcard_all(struct lttng_event_enabler_common *event_enabler)
+{
+       if (event_enabler->event_param.instrumentation != LTTNG_KERNEL_ABI_SYSCALL)
+               return false;
+       if (event_enabler->event_param.u.syscall.abi != LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL)
+               return false;
+       if (event_enabler->event_param.u.syscall.match != LTTNG_KERNEL_ABI_SYSCALL_MATCH_NAME)
+               return false;
+       if (strcmp(event_enabler->event_param.name, "*"))
+               return false;
+       return true;
+}
+
 static
 void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabler, enum sc_type type)
 {
@@ -688,6 +712,22 @@ void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabl
        bool found = false;
        struct hlist_head *head;
 
+#ifndef CONFIG_COMPAT
+       if (type == SC_TYPE_COMPAT_ENTRY || type == SC_TYPE_COMPAT_EXIT)
+               return;
+#endif
+       /*
+        * Considering that currently system calls can only be enabled on a per
+        * name basis (or wildcard based on a name), unknown syscall events are
+        * only used when matching *all* system calls, because this is the only
+        * case which can be associated with an unknown system call.
+        *
+        * When enabling system call on a per system call number basis will be
+        * supported, this will need to be revisited.
+        */
+       if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
+               return;
+
        switch (type) {
        case SC_TYPE_ENTRY:
                desc = &__event_desc___syscall_entry_unknown;
@@ -714,42 +754,37 @@ void create_unknown_syscall_event(struct lttng_event_enabler_common *event_enabl
         */
        head = utils_borrow_hash_table_bucket(events_ht->table, LTTNG_EVENT_HT_SIZE, desc->event_name);
        lttng_hlist_for_each_entry(event_priv, head, hlist_node) {
-               if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub))
+               if (lttng_event_enabler_desc_match_event(event_enabler, desc, event_priv->pub)) {
                        found = true;
+                       break;
+               }
        }
        if (!found)
                lttng_syscall_event_enabler_create_event(event_enabler, desc, unknown_dispatch_list, type, -1U);
 }
 
 static
-int lttng_syscalls_populate_events(struct lttng_event_enabler_common *syscall_event_enabler)
+void lttng_syscall_event_enabler_create_matching_events(struct lttng_event_enabler_common *event_enabler)
 {
-       struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_enabler(syscall_event_enabler);
-       struct lttng_event_recorder_enabler *event_recorder_enabler;
-       struct lttng_kernel_channel_buffer *chan;
-       int ret;
-
-       if (syscall_event_enabler->enabler_type != LTTNG_EVENT_ENABLER_TYPE_RECORDER)
-               return 0;
-       event_recorder_enabler = container_of(syscall_event_enabler, struct lttng_event_recorder_enabler, parent);
-       chan = event_recorder_enabler->chan;
+       enum lttng_kernel_abi_syscall_entryexit entryexit = event_enabler->event_param.u.syscall.entryexit;
 
-       lttng_syscall_event_enabler_create_matching_events(&event_recorder_enabler->parent, sc_table.table, sc_table.len,
-                       syscall_table->syscall_dispatch, SC_TYPE_ENTRY);
-       lttng_syscall_event_enabler_create_matching_events(&event_recorder_enabler->parent, sc_exit_table.table, sc_exit_table.len,
-                       syscall_table->syscall_exit_dispatch, SC_TYPE_EXIT);
-       create_unknown_syscall_event(syscall_event_enabler, SC_TYPE_ENTRY);
-       create_unknown_syscall_event(syscall_event_enabler, SC_TYPE_EXIT);
+       if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
+               lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
+                       sc_table.table, sc_table.len, SC_TYPE_ENTRY);
+               lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
+                       compat_sc_table.table, compat_sc_table.len, SC_TYPE_COMPAT_ENTRY);
+               create_unknown_syscall_event(event_enabler, SC_TYPE_ENTRY);
+               create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_ENTRY);
+       }
 
-#ifdef CONFIG_COMPAT
-       lttng_syscall_event_enabler_create_matching_events(&event_recorder_enabler->parent, compat_sc_table.table, compat_sc_table.len,
-                       syscall_table->compat_syscall_dispatch, SC_TYPE_COMPAT_ENTRY);
-       lttng_syscall_event_enabler_create_matching_events(&event_recorder_enabler->parent, compat_sc_exit_table.table, compat_sc_exit_table.len,
-                       syscall_table->compat_syscall_exit_dispatch, SC_TYPE_COMPAT_EXIT);
-       create_unknown_syscall_event(syscall_event_enabler, SC_TYPE_COMPAT_ENTRY);
-       create_unknown_syscall_event(syscall_event_enabler, SC_TYPE_COMPAT_EXIT);
-#endif
-       return ret;
+       if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
+               lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
+                       sc_exit_table.table, sc_exit_table.len, SC_TYPE_EXIT);
+               lttng_syscall_event_enabler_create_matching_syscall_table_events(event_enabler,
+                       compat_sc_exit_table.table, compat_sc_exit_table.len, SC_TYPE_COMPAT_EXIT);
+               create_unknown_syscall_event(event_enabler, SC_TYPE_EXIT);
+               create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_EXIT);
+       }
 }
 
 /*
@@ -773,7 +808,6 @@ int lttng_event_enabler_create_syscall_events_if_missing(struct lttng_event_enab
                        return -ENOMEM;
        }
 
-
 #ifdef CONFIG_COMPAT
        if (!syscall_table->compat_syscall_dispatch) {
                /* create syscall table mapping compat syscall to events */
@@ -796,14 +830,6 @@ int lttng_event_enabler_create_syscall_events_if_missing(struct lttng_event_enab
                        return -ENOMEM;
        }
 
-       ret = lttng_syscalls_populate_events(syscall_event_enabler);
-       if (ret)
-               return ret;
-
-       ret = lttng_syscalls_create_matching_event_notifiers(syscall_event_enabler);
-       if (ret)
-               return ret;
-
        if (!syscall_table->sys_enter_registered) {
                ret = lttng_wrapper_tracepoint_probe_register("sys_enter",
                                (void *) syscall_entry_event_probe, syscall_table);
@@ -822,38 +848,8 @@ int lttng_event_enabler_create_syscall_events_if_missing(struct lttng_event_enab
                syscall_table->sys_exit_registered = 1;
        }
 
-       return ret;
-}
+       lttng_syscall_event_enabler_create_matching_events(syscall_event_enabler);
 
-static
-int lttng_syscalls_create_matching_event_notifiers(struct lttng_event_enabler_common *event_enabler)
-{
-       int ret;
-       enum lttng_kernel_abi_syscall_entryexit entryexit =
-                       event_enabler->event_param.u.syscall.entryexit;
-       struct lttng_event_notifier_enabler *event_notifier_enabler;
-
-       if (event_enabler->enabler_type != LTTNG_EVENT_ENABLER_TYPE_NOTIFIER)
-               return 0;
-       event_notifier_enabler = container_of(event_enabler, struct lttng_event_notifier_enabler, parent);
-
-       if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
-               lttng_syscall_event_enabler_create_matching_events(&event_notifier_enabler->parent,
-                       sc_table.table, sc_table.len, NULL, SC_TYPE_ENTRY);
-               lttng_syscall_event_enabler_create_matching_events(&event_notifier_enabler->parent,
-                       compat_sc_table.table, compat_sc_table.len, NULL, SC_TYPE_COMPAT_ENTRY);
-               create_unknown_syscall_event(event_enabler, SC_TYPE_ENTRY);
-               create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_ENTRY);
-       }
-
-       if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_EXIT || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT) {
-               lttng_syscall_event_enabler_create_matching_events(&event_notifier_enabler->parent,
-                       sc_exit_table.table, sc_exit_table.len, NULL, SC_TYPE_EXIT);
-               lttng_syscall_event_enabler_create_matching_events(&event_notifier_enabler->parent,
-                       compat_sc_exit_table.table, compat_sc_exit_table.len, NULL, SC_TYPE_COMPAT_EXIT);
-               create_unknown_syscall_event(event_enabler, SC_TYPE_EXIT);
-               create_unknown_syscall_event(event_enabler, SC_TYPE_COMPAT_EXIT);
-       }
        return ret;
 }
 
@@ -986,6 +982,7 @@ int lttng_syscall_filter_enable(
 {
        const char *syscall_name;
        unsigned long *bitmap;
+       u32 *refcount_map;
        int syscall_nr;
 
        syscall_name = get_syscall_name(desc_name, abi, entryexit);
@@ -1008,9 +1005,11 @@ int lttng_syscall_filter_enable(
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_entry;
+                       refcount_map = filter->sc_entry_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_entry;
+                       refcount_map = filter->sc_compat_entry_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1020,9 +1019,11 @@ int lttng_syscall_filter_enable(
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_exit;
+                       refcount_map = filter->sc_exit_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_exit;
+                       refcount_map = filter->sc_compat_exit_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1031,72 +1032,65 @@ int lttng_syscall_filter_enable(
        default:
                return -EINVAL;
        }
-       if (test_bit(syscall_nr, bitmap))
-               return -EEXIST;
-       bitmap_set(bitmap, syscall_nr, 1);
+       if (refcount_map[syscall_nr] == U32_MAX)
+               return -EOVERFLOW;
+       if (refcount_map[syscall_nr]++ == 0)
+               bitmap_set(bitmap, syscall_nr, 1);
        return 0;
 }
 
 int lttng_syscall_filter_enable_event(struct lttng_kernel_event_common *event)
 {
        struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
+       unsigned int syscall_id = event->priv->u.syscall.syscall_id;
+       struct hlist_head *dispatch_list;
        int ret;
 
        WARN_ON_ONCE(event->priv->instrumentation != LTTNG_KERNEL_ABI_SYSCALL);
 
+       /* Skip unknown syscall */
+       if (syscall_id == -1U)
+               return 0;
+
        ret = lttng_syscall_filter_enable(syscall_table->sc_filter,
                event->priv->desc->event_name, event->priv->u.syscall.abi,
                event->priv->u.syscall.entryexit);
        if (ret)
                return ret;
 
-       switch (event->type) {
-       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
+       switch (event->priv->u.syscall.entryexit) {
+       case LTTNG_SYSCALL_ENTRY:
+               switch (event->priv->u.syscall.abi) {
+               case LTTNG_SYSCALL_ABI_NATIVE:
+                       dispatch_list = &syscall_table->syscall_dispatch[syscall_id];
+                       break;
+               case LTTNG_SYSCALL_ABI_COMPAT:
+                       dispatch_list = &syscall_table->compat_syscall_dispatch[syscall_id];
+                       break;
+               default:
+                       ret = -EINVAL;
+                       goto end;
+               }
                break;
-       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
-       {
-               unsigned int syscall_id = event->priv->u.syscall.syscall_id;
-               struct hlist_head *dispatch_list;
-
-               switch (event->priv->u.syscall.entryexit) {
-               case LTTNG_SYSCALL_ENTRY:
-                       switch (event->priv->u.syscall.abi) {
-                       case LTTNG_SYSCALL_ABI_NATIVE:
-                               dispatch_list = &syscall_table->syscall_dispatch[syscall_id];
-                               break;
-                       case LTTNG_SYSCALL_ABI_COMPAT:
-                               dispatch_list = &syscall_table->compat_syscall_dispatch[syscall_id];
-                               break;
-                       default:
-                               ret = -EINVAL;
-                               goto end;
-                       }
+       case LTTNG_SYSCALL_EXIT:
+               switch (event->priv->u.syscall.abi) {
+               case LTTNG_SYSCALL_ABI_NATIVE:
+                       dispatch_list = &syscall_table->syscall_exit_dispatch[syscall_id];
                        break;
-               case LTTNG_SYSCALL_EXIT:
-                       switch (event->priv->u.syscall.abi) {
-                       case LTTNG_SYSCALL_ABI_NATIVE:
-                               dispatch_list = &syscall_table->syscall_exit_dispatch[syscall_id];
-                               break;
-                       case LTTNG_SYSCALL_ABI_COMPAT:
-                               dispatch_list = &syscall_table->compat_syscall_exit_dispatch[syscall_id];
-                               break;
-                       default:
-                               ret = -EINVAL;
-                               goto end;
-                       }
+               case LTTNG_SYSCALL_ABI_COMPAT:
+                       dispatch_list = &syscall_table->compat_syscall_exit_dispatch[syscall_id];
                        break;
                default:
                        ret = -EINVAL;
                        goto end;
                }
-
-               hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_list);
                break;
-       }
        default:
-               WARN_ON_ONCE(1);
-               return -ENOSYS;
+               ret = -EINVAL;
+               goto end;
        }
+
+       hlist_add_head_rcu(&event->priv->u.syscall.node, dispatch_list);
 end:
        return ret;
 }
@@ -1108,6 +1102,7 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
 {
        const char *syscall_name;
        unsigned long *bitmap;
+       u32 *refcount_map;
        int syscall_nr;
 
        syscall_name = get_syscall_name(desc_name, abi, entryexit);
@@ -1130,9 +1125,11 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_entry;
+                       refcount_map = filter->sc_entry_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_entry;
+                       refcount_map = filter->sc_compat_entry_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1142,9 +1139,11 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
                switch (abi) {
                case LTTNG_SYSCALL_ABI_NATIVE:
                        bitmap = filter->sc_exit;
+                       refcount_map = filter->sc_exit_refcount_map;
                        break;
                case LTTNG_SYSCALL_ABI_COMPAT:
                        bitmap = filter->sc_compat_exit;
+                       refcount_map = filter->sc_compat_exit_refcount_map;
                        break;
                default:
                        return -EINVAL;
@@ -1153,36 +1152,29 @@ int lttng_syscall_filter_disable(struct lttng_syscall_filter *filter,
        default:
                return -EINVAL;
        }
-       if (!test_bit(syscall_nr, bitmap))
-               return -EEXIST;
-       bitmap_clear(bitmap, syscall_nr, 1);
-
+       if (refcount_map[syscall_nr] == 0)
+               return -ENOENT;
+       if (--refcount_map[syscall_nr] == 0)
+               bitmap_clear(bitmap, syscall_nr, 1);
        return 0;
 }
 
 int lttng_syscall_filter_disable_event(struct lttng_kernel_event_common *event)
 {
        struct lttng_kernel_syscall_table *syscall_table = get_syscall_table_from_event(event);
+       unsigned int syscall_id = event->priv->u.syscall.syscall_id;
        int ret;
 
+       /* Skip unknown syscall */
+       if (syscall_id == -1U)
+               return 0;
+
        ret = lttng_syscall_filter_disable(syscall_table->sc_filter,
                event->priv->desc->event_name, event->priv->u.syscall.abi,
                event->priv->u.syscall.entryexit);
        if (ret)
                return ret;
-
-       switch (event->type) {
-       case LTTNG_KERNEL_EVENT_TYPE_RECORDER:
-               break;
-       case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER:
-       {
-               hlist_del_rcu(&event->priv->u.syscall.node);
-               break;
-       }
-       default:
-               WARN_ON_ONCE(1);
-               return -ENOSYS;
-       }
+       hlist_del_rcu(&event->priv->u.syscall.node);
        return 0;
 }
 
@@ -1192,15 +1184,8 @@ void lttng_syscall_table_set_wildcard_all(struct lttng_event_enabler_common *eve
        enum lttng_kernel_abi_syscall_entryexit entryexit;
        int enabled = event_enabler->enabled;
 
-       if (event_enabler->event_param.instrumentation != LTTNG_KERNEL_ABI_SYSCALL)
+       if (!lttng_syscall_event_enabler_is_wildcard_all(event_enabler))
                return;
-       if (event_enabler->event_param.u.syscall.abi != LTTNG_KERNEL_ABI_SYSCALL_ABI_ALL)
-               return;
-       if (event_enabler->event_param.u.syscall.match != LTTNG_KERNEL_ABI_SYSCALL_MATCH_NAME)
-               return;
-       if (strcmp(event_enabler->event_param.name, "*"))
-               return;
-
        entryexit = event_enabler->event_param.u.syscall.entryexit;
        if (entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRY || entryexit == LTTNG_KERNEL_ABI_SYSCALL_ENTRYEXIT)
                WRITE_ONCE(syscall_table->syscall_all_entry, enabled);
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