+ if (chan->sys_enter_registered) {
+ ret = lttng_wrapper_tracepoint_probe_unregister("sys_enter",
+ (void *) syscall_entry_probe, chan);
+ if (ret)
+ return ret;
+ chan->sys_enter_registered = 0;
+ }
+ if (chan->sys_exit_registered) {
+ ret = lttng_wrapper_tracepoint_probe_unregister("sys_exit",
+ (void *) syscall_exit_probe, chan);
+ if (ret)
+ return ret;
+ chan->sys_exit_registered = 0;
+ }
+ /* lttng_event destroy will be performed by lttng_session_destroy() */
+ kfree(chan->sc_table);
+ kfree(chan->sc_exit_table);
+#ifdef CONFIG_COMPAT
+ kfree(chan->compat_sc_table);
+ kfree(chan->compat_sc_exit_table);
+#endif
+ kfree(chan->sc_filter);
+ return 0;
+}
+
+static
+int get_syscall_nr(const char *syscall_name)
+{
+ int syscall_nr = -1;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(sc_table); i++) {
+ const struct trace_syscall_entry *entry;
+ const char *it_name;
+
+ entry = &sc_table[i];
+ if (!entry->desc)
+ continue;
+ it_name = entry->desc->name;
+ it_name += strlen(SYSCALL_ENTRY_STR);
+ if (!strcmp(syscall_name, it_name)) {
+ syscall_nr = i;
+ break;
+ }
+ }
+ return syscall_nr;
+}
+
+static
+int get_compat_syscall_nr(const char *syscall_name)
+{
+ int syscall_nr = -1;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(compat_sc_table); i++) {
+ const struct trace_syscall_entry *entry;
+ const char *it_name;
+
+ entry = &compat_sc_table[i];
+ if (!entry->desc)
+ continue;
+ it_name = entry->desc->name;
+ it_name += strlen(COMPAT_SYSCALL_ENTRY_STR);
+ if (!strcmp(syscall_name, it_name)) {
+ syscall_nr = i;
+ break;
+ }
+ }
+ return syscall_nr;
+}
+
+static
+uint32_t get_sc_tables_len(void)
+{
+ return ARRAY_SIZE(sc_table) + ARRAY_SIZE(compat_sc_table);
+}
+
+int lttng_syscall_filter_enable(struct lttng_channel *chan,
+ const char *name)
+{
+ int syscall_nr, compat_syscall_nr, ret;
+ struct lttng_syscall_filter *filter;
+
+ WARN_ON_ONCE(!chan->sc_table);
+
+ if (!name) {
+ /* Enable all system calls by removing filter */
+ if (chan->sc_filter) {
+ filter = chan->sc_filter;
+ rcu_assign_pointer(chan->sc_filter, NULL);
+ synchronize_trace();
+ kfree(filter);
+ }
+ chan->syscall_all = 1;
+ return 0;
+ }
+
+ if (!chan->sc_filter) {
+ if (chan->syscall_all) {
+ /*
+ * All syscalls are already enabled.
+ */
+ return -EEXIST;
+ }
+ filter = kzalloc(sizeof(struct lttng_syscall_filter),
+ GFP_KERNEL);
+ if (!filter)
+ return -ENOMEM;
+ } else {
+ filter = chan->sc_filter;
+ }
+ syscall_nr = get_syscall_nr(name);
+ compat_syscall_nr = get_compat_syscall_nr(name);
+ if (syscall_nr < 0 && compat_syscall_nr < 0) {
+ ret = -ENOENT;
+ goto error;
+ }
+ if (syscall_nr >= 0) {
+ if (test_bit(syscall_nr, filter->sc)) {
+ ret = -EEXIST;
+ goto error;
+ }
+ bitmap_set(filter->sc, syscall_nr, 1);
+ }
+ if (compat_syscall_nr >= 0) {
+ if (test_bit(compat_syscall_nr, filter->sc_compat)) {
+ ret = -EEXIST;
+ goto error;
+ }
+ bitmap_set(filter->sc_compat, compat_syscall_nr, 1);
+ }
+ if (!chan->sc_filter)
+ rcu_assign_pointer(chan->sc_filter, filter);
+ return 0;
+
+error:
+ if (!chan->sc_filter)
+ kfree(filter);
+ return ret;
+}
+
+int lttng_syscall_filter_disable(struct lttng_channel *chan,
+ const char *name)
+{
+ int syscall_nr, compat_syscall_nr, ret;
+ struct lttng_syscall_filter *filter;
+
+ WARN_ON_ONCE(!chan->sc_table);
+
+ if (!chan->sc_filter) {
+ if (!chan->syscall_all)
+ return -EEXIST;
+ filter = kzalloc(sizeof(struct lttng_syscall_filter),
+ GFP_KERNEL);
+ if (!filter)
+ return -ENOMEM;
+ /* Trace all system calls, then apply disable. */
+ bitmap_set(filter->sc, 0, NR_syscalls);
+ bitmap_set(filter->sc_compat, 0, NR_compat_syscalls);
+ } else {
+ filter = chan->sc_filter;
+ }
+
+ if (!name) {
+ /* Fail if all syscalls are already disabled. */
+ if (bitmap_empty(filter->sc, NR_syscalls)
+ && bitmap_empty(filter->sc_compat,
+ NR_compat_syscalls)) {
+ ret = -EEXIST;
+ goto error;
+ }
+
+ /* Disable all system calls */
+ bitmap_clear(filter->sc, 0, NR_syscalls);
+ bitmap_clear(filter->sc_compat, 0, NR_compat_syscalls);
+ goto apply_filter;
+ }
+ syscall_nr = get_syscall_nr(name);
+ compat_syscall_nr = get_compat_syscall_nr(name);
+ if (syscall_nr < 0 && compat_syscall_nr < 0) {
+ ret = -ENOENT;
+ goto error;
+ }
+ if (syscall_nr >= 0) {
+ if (!test_bit(syscall_nr, filter->sc)) {
+ ret = -EEXIST;
+ goto error;
+ }
+ bitmap_clear(filter->sc, syscall_nr, 1);
+ }
+ if (compat_syscall_nr >= 0) {
+ if (!test_bit(compat_syscall_nr, filter->sc_compat)) {
+ ret = -EEXIST;
+ goto error;
+ }
+ bitmap_clear(filter->sc_compat, compat_syscall_nr, 1);
+ }
+apply_filter:
+ if (!chan->sc_filter)
+ rcu_assign_pointer(chan->sc_filter, filter);
+ chan->syscall_all = 0;
+ return 0;
+
+error:
+ if (!chan->sc_filter)
+ kfree(filter);
+ return ret;
+}
+
+static
+const struct trace_syscall_entry *syscall_list_get_entry(loff_t *pos)
+{
+ const struct trace_syscall_entry *entry;
+ int iter = 0;
+
+ for (entry = sc_table;
+ entry < sc_table + ARRAY_SIZE(sc_table);
+ entry++) {
+ if (iter++ >= *pos)
+ return entry;
+ }
+ for (entry = compat_sc_table;
+ entry < compat_sc_table + ARRAY_SIZE(compat_sc_table);
+ entry++) {
+ if (iter++ >= *pos)
+ return entry;
+ }
+ /* End of list */
+ return NULL;
+}
+
+static
+void *syscall_list_start(struct seq_file *m, loff_t *pos)
+{
+ return (void *) syscall_list_get_entry(pos);
+}
+
+static
+void *syscall_list_next(struct seq_file *m, void *p, loff_t *ppos)
+{
+ (*ppos)++;
+ return (void *) syscall_list_get_entry(ppos);
+}
+
+static
+void syscall_list_stop(struct seq_file *m, void *p)
+{
+}
+
+static
+int get_sc_table(const struct trace_syscall_entry *entry,
+ const struct trace_syscall_entry **table,
+ unsigned int *bitness)
+{
+ if (entry >= sc_table && entry < sc_table + ARRAY_SIZE(sc_table)) {
+ if (bitness)
+ *bitness = BITS_PER_LONG;
+ if (table)
+ *table = sc_table;
+ return 0;
+ }
+ if (!(entry >= compat_sc_table
+ && entry < compat_sc_table + ARRAY_SIZE(compat_sc_table))) {
+ return -EINVAL;
+ }
+ if (bitness)
+ *bitness = 32;
+ if (table)
+ *table = compat_sc_table;
+ return 0;
+}
+
+static
+int syscall_list_show(struct seq_file *m, void *p)
+{
+ const struct trace_syscall_entry *table, *entry = p;
+ unsigned int bitness;
+ unsigned long index;
+ int ret;
+ const char *name;
+
+ ret = get_sc_table(entry, &table, &bitness);