--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * event probes
+ *
+ * Part of this code was copied from kernel/trace/trace_kprobe.c written by
+ * Masami Hiramatsu <mhiramat@kernel.org>
+ *
+ * Copyright (C) 2021, VMware Inc, Steven Rostedt <rostedt@goodmis.org>
+ * Copyright (C) 2021, VMware Inc, Tzvetomir Stoyanov tz.stoyanov@gmail.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/ftrace.h>
+
+#include "trace_dynevent.h"
+#include "trace_probe.h"
+#include "trace_probe_tmpl.h"
+
+#define EPROBE_EVENT_SYSTEM "eprobes"
+
+struct trace_eprobe {
+ /* tracepoint system */
+ const char *event_system;
+
+ /* tracepoint event */
+ const char *event_name;
+
+ struct trace_event_call *event;
+
+ struct dyn_event devent;
+ struct trace_probe tp;
+};
+
+struct eprobe_data {
+ struct trace_event_file *file;
+ struct trace_eprobe *ep;
+};
+
+static int __trace_eprobe_create(int argc, const char *argv[]);
+
+static void trace_event_probe_cleanup(struct trace_eprobe *ep)
+{
+ if (!ep)
+ return;
+ trace_probe_cleanup(&ep->tp);
+ kfree(ep->event_name);
+ kfree(ep->event_system);
+ if (ep->event)
+ trace_event_put_ref(ep->event);
+ kfree(ep);
+}
+
+static struct trace_eprobe *to_trace_eprobe(struct dyn_event *ev)
+{
+ return container_of(ev, struct trace_eprobe, devent);
+}
+
+static int eprobe_dyn_event_create(const char *raw_command)
+{
+ return trace_probe_create(raw_command, __trace_eprobe_create);
+}
+
+static int eprobe_dyn_event_show(struct seq_file *m, struct dyn_event *ev)
+{
+ struct trace_eprobe *ep = to_trace_eprobe(ev);
+ int i;
+
+ seq_printf(m, "e:%s/%s", trace_probe_group_name(&ep->tp),
+ trace_probe_name(&ep->tp));
+ seq_printf(m, " %s.%s", ep->event_system, ep->event_name);
+
+ for (i = 0; i < ep->tp.nr_args; i++)
+ seq_printf(m, " %s=%s", ep->tp.args[i].name, ep->tp.args[i].comm);
+ seq_putc(m, '\n');
+
+ return 0;
+}
+
+static int unregister_trace_eprobe(struct trace_eprobe *ep)
+{
+ /* If other probes are on the event, just unregister eprobe */
+ if (trace_probe_has_sibling(&ep->tp))
+ goto unreg;
+
+ /* Enabled event can not be unregistered */
+ if (trace_probe_is_enabled(&ep->tp))
+ return -EBUSY;
+
+ /* Will fail if probe is being used by ftrace or perf */
+ if (trace_probe_unregister_event_call(&ep->tp))
+ return -EBUSY;
+
+unreg:
+ dyn_event_remove(&ep->devent);
+ trace_probe_unlink(&ep->tp);
+
+ return 0;
+}
+
+static int eprobe_dyn_event_release(struct dyn_event *ev)
+{
+ struct trace_eprobe *ep = to_trace_eprobe(ev);
+ int ret = unregister_trace_eprobe(ep);
+
+ if (!ret)
+ trace_event_probe_cleanup(ep);
+ return ret;
+}
+
+static bool eprobe_dyn_event_is_busy(struct dyn_event *ev)
+{
+ struct trace_eprobe *ep = to_trace_eprobe(ev);
+
+ return trace_probe_is_enabled(&ep->tp);
+}
+
+static bool eprobe_dyn_event_match(const char *system, const char *event,
+ int argc, const char **argv, struct dyn_event *ev)
+{
+ struct trace_eprobe *ep = to_trace_eprobe(ev);
+
+ return strcmp(trace_probe_name(&ep->tp), event) == 0 &&
+ (!system || strcmp(trace_probe_group_name(&ep->tp), system) == 0) &&
+ trace_probe_match_command_args(&ep->tp, argc, argv);
+}
+
+static struct dyn_event_operations eprobe_dyn_event_ops = {
+ .create = eprobe_dyn_event_create,
+ .show = eprobe_dyn_event_show,
+ .is_busy = eprobe_dyn_event_is_busy,
+ .free = eprobe_dyn_event_release,
+ .match = eprobe_dyn_event_match,
+};
+
+static struct trace_eprobe *alloc_event_probe(const char *group,
+ const char *this_event,
+ struct trace_event_call *event,
+ int nargs)
+{
+ struct trace_eprobe *ep;
+ const char *event_name;
+ const char *sys_name;
+ int ret = -ENOMEM;
+
+ if (!event)
+ return ERR_PTR(-ENODEV);
+
+ sys_name = event->class->system;
+ event_name = trace_event_name(event);
+
+ ep = kzalloc(struct_size(ep, tp.args, nargs), GFP_KERNEL);
+ if (!ep) {
+ trace_event_put_ref(ep->event);
+ goto error;
+ }
+ ep->event = event;
+ ep->event_name = kstrdup(event_name, GFP_KERNEL);
+ if (!ep->event_name)
+ goto error;
+ ep->event_system = kstrdup(sys_name, GFP_KERNEL);
+ if (!ep->event_system)
+ goto error;
+
+ ret = trace_probe_init(&ep->tp, this_event, group, false);
+ if (ret < 0)
+ goto error;
+
+ dyn_event_init(&ep->devent, &eprobe_dyn_event_ops);
+ return ep;
+error:
+ trace_event_probe_cleanup(ep);
+ return ERR_PTR(ret);
+}
+
+static int trace_eprobe_tp_arg_update(struct trace_eprobe *ep, int i)
+{
+ struct probe_arg *parg = &ep->tp.args[i];
+ struct ftrace_event_field *field;
+ struct list_head *head;
+
+ head = trace_get_fields(ep->event);
+ list_for_each_entry(field, head, link) {
+ if (!strcmp(parg->code->data, field->name)) {
+ kfree(parg->code->data);
+ parg->code->data = field;
+ return 0;
+ }
+ }
+ kfree(parg->code->data);
+ parg->code->data = NULL;
+ return -ENOENT;
+}
+
+static int eprobe_event_define_fields(struct trace_event_call *event_call)
+{
+ int ret;
+ struct eprobe_trace_entry_head field;
+ struct trace_probe *tp;
+
+ tp = trace_probe_primary_from_call(event_call);
+ if (WARN_ON_ONCE(!tp))
+ return -ENOENT;
+
+ DEFINE_FIELD(unsigned int, type, FIELD_STRING_TYPE, 0);
+
+ return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
+}
+
+static struct trace_event_fields eprobe_fields_array[] = {
+ { .type = TRACE_FUNCTION_TYPE,
+ .define_fields = eprobe_event_define_fields },
+ {}
+};
+
+/* Event entry printers */
+static enum print_line_t
+print_eprobe_event(struct trace_iterator *iter, int flags,
+ struct trace_event *event)
+{
+ struct eprobe_trace_entry_head *field;
+ struct trace_event_call *pevent;
+ struct trace_event *probed_event;
+ struct trace_seq *s = &iter->seq;
+ struct trace_probe *tp;
+
+ field = (struct eprobe_trace_entry_head *)iter->ent;
+ tp = trace_probe_primary_from_call(
+ container_of(event, struct trace_event_call, event));
+ if (WARN_ON_ONCE(!tp))
+ goto out;
+
+ trace_seq_printf(s, "%s: (", trace_probe_name(tp));
+
+ probed_event = ftrace_find_event(field->type);
+ if (probed_event) {
+ pevent = container_of(probed_event, struct trace_event_call, event);
+ trace_seq_printf(s, "%s.%s", pevent->class->system,
+ trace_event_name(pevent));
+ } else {
+ trace_seq_printf(s, "%u", field->type);
+ }
+
+ trace_seq_putc(s, ')');
+
+ if (print_probe_args(s, tp->args, tp->nr_args,
+ (u8 *)&field[1], field) < 0)
+ goto out;
+
+ trace_seq_putc(s, '\n');
+ out:
+ return trace_handle_return(s);
+}
+
+static unsigned long get_event_field(struct fetch_insn *code, void *rec)
+{
+ struct ftrace_event_field *field = code->data;
+ unsigned long val;
+ void *addr;
+
+ addr = rec + field->offset;
+
+ switch (field->size) {
+ case 1:
+ if (field->is_signed)
+ val = *(char *)addr;
+ else
+ val = *(unsigned char *)addr;
+ break;
+ case 2:
+ if (field->is_signed)
+ val = *(short *)addr;
+ else
+ val = *(unsigned short *)addr;
+ break;
+ case 4:
+ if (field->is_signed)
+ val = *(int *)addr;
+ else
+ val = *(unsigned int *)addr;
+ break;
+ default:
+ if (field->is_signed)
+ val = *(long *)addr;
+ else
+ val = *(unsigned long *)addr;
+ break;
+ }
+ return val;
+}
+
+static int get_eprobe_size(struct trace_probe *tp, void *rec)
+{
+ struct probe_arg *arg;
+ int i, len, ret = 0;
+
+ for (i = 0; i < tp->nr_args; i++) {
+ arg = tp->args + i;
+ if (unlikely(arg->dynamic)) {
+ unsigned long val;
+
+ val = get_event_field(arg->code, rec);
+ len = process_fetch_insn_bottom(arg->code + 1, val, NULL, NULL);
+ if (len > 0)
+ ret += len;
+ }
+ }
+
+ return ret;
+}
+
+/* Kprobe specific fetch functions */
+
+/* Note that we don't verify it, since the code does not come from user space */
+static int
+process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
+ void *base)
+{
+ unsigned long val;
+
+ val = get_event_field(code, rec);
+ return process_fetch_insn_bottom(code + 1, val, dest, base);
+}
+NOKPROBE_SYMBOL(process_fetch_insn)
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen_user(unsigned long addr)
+{
+ const void __user *uaddr = (__force const void __user *)addr;
+
+ return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
+}
+
+/* Return the length of string -- including null terminal byte */
+static nokprobe_inline int
+fetch_store_strlen(unsigned long addr)
+{
+ int ret, len = 0;
+ u8 c;
+
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ if (addr < TASK_SIZE)
+ return fetch_store_strlen_user(addr);
+#endif
+
+ do {
+ ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
+ len++;
+ } while (c && ret == 0 && len < MAX_STRING_SIZE);
+
+ return (ret < 0) ? ret : len;
+}
+
+/*
+ * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
+ * with max length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string_user(unsigned long addr, void *dest, void *base)
+{
+ const void __user *uaddr = (__force const void __user *)addr;
+ int maxlen = get_loc_len(*(u32 *)dest);
+ void *__dest;
+ long ret;
+
+ if (unlikely(!maxlen))
+ return -ENOMEM;
+
+ __dest = get_loc_data(dest, base);
+
+ ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
+ if (ret >= 0)
+ *(u32 *)dest = make_data_loc(ret, __dest - base);
+
+ return ret;
+}
+
+/*
+ * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
+ * length and relative data location.
+ */
+static nokprobe_inline int
+fetch_store_string(unsigned long addr, void *dest, void *base)
+{
+ int maxlen = get_loc_len(*(u32 *)dest);
+ void *__dest;
+ long ret;
+
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ if ((unsigned long)addr < TASK_SIZE)
+ return fetch_store_string_user(addr, dest, base);
+#endif
+
+ if (unlikely(!maxlen))
+ return -ENOMEM;
+
+ __dest = get_loc_data(dest, base);
+
+ /*
+ * Try to get string again, since the string can be changed while
+ * probing.
+ */
+ ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
+ if (ret >= 0)
+ *(u32 *)dest = make_data_loc(ret, __dest - base);
+
+ return ret;
+}
+
+static nokprobe_inline int
+probe_mem_read_user(void *dest, void *src, size_t size)
+{
+ const void __user *uaddr = (__force const void __user *)src;
+
+ return copy_from_user_nofault(dest, uaddr, size);
+}
+
+static nokprobe_inline int
+probe_mem_read(void *dest, void *src, size_t size)
+{
+#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
+ if ((unsigned long)src < TASK_SIZE)
+ return probe_mem_read_user(dest, src, size);
+#endif
+ return copy_from_kernel_nofault(dest, src, size);
+}
+
+/* eprobe handler */
+static inline void
+__eprobe_trace_func(struct eprobe_data *edata, void *rec)
+{
+ struct eprobe_trace_entry_head *entry;
+ struct trace_event_call *call = trace_probe_event_call(&edata->ep->tp);
+ struct trace_event_buffer fbuffer;
+ int dsize;
+
+ if (WARN_ON_ONCE(call != edata->file->event_call))
+ return;
+
+ if (trace_trigger_soft_disabled(edata->file))
+ return;
+
+ fbuffer.trace_ctx = tracing_gen_ctx();
+ fbuffer.trace_file = edata->file;
+
+ dsize = get_eprobe_size(&edata->ep->tp, rec);
+ fbuffer.regs = NULL;
+
+ fbuffer.event =
+ trace_event_buffer_lock_reserve(&fbuffer.buffer, edata->file,
+ call->event.type,
+ sizeof(*entry) + edata->ep->tp.size + dsize,
+ fbuffer.trace_ctx);
+ if (!fbuffer.event)
+ return;
+
+ entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
+ if (edata->ep->event)
+ entry->type = edata->ep->event->event.type;
+ else
+ entry->type = 0;
+ store_trace_args(&entry[1], &edata->ep->tp, rec, sizeof(*entry), dsize);
+
+ trace_event_buffer_commit(&fbuffer);
+}
+
+/*
+ * The event probe implementation uses event triggers to get access to
+ * the event it is attached to, but is not an actual trigger. The below
+ * functions are just stubs to fulfill what is needed to use the trigger
+ * infrastructure.
+ */
+static int eprobe_trigger_init(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ return 0;
+}
+
+static void eprobe_trigger_free(struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+
+}
+
+static int eprobe_trigger_print(struct seq_file *m,
+ struct event_trigger_ops *ops,
+ struct event_trigger_data *data)
+{
+ /* Do not print eprobe event triggers */
+ return 0;
+}
+
+static void eprobe_trigger_func(struct event_trigger_data *data,
+ struct trace_buffer *buffer, void *rec,
+ struct ring_buffer_event *rbe)
+{
+ struct eprobe_data *edata = data->private_data;
+
+ __eprobe_trace_func(edata, rec);
+}
+
+static struct event_trigger_ops eprobe_trigger_ops = {
+ .func = eprobe_trigger_func,
+ .print = eprobe_trigger_print,
+ .init = eprobe_trigger_init,
+ .free = eprobe_trigger_free,
+};
+
+static int eprobe_trigger_cmd_func(struct event_command *cmd_ops,
+ struct trace_event_file *file,
+ char *glob, char *cmd, char *param)
+{
+ return -1;
+}
+
+static int eprobe_trigger_reg_func(char *glob, struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+ return -1;
+}
+
+static void eprobe_trigger_unreg_func(char *glob, struct event_trigger_ops *ops,
+ struct event_trigger_data *data,
+ struct trace_event_file *file)
+{
+
+}
+
+static struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd,
+ char *param)
+{
+ return &eprobe_trigger_ops;
+}
+
+static struct event_command event_trigger_cmd = {
+ .name = "eprobe",
+ .trigger_type = ETT_EVENT_EPROBE,
+ .flags = EVENT_CMD_FL_NEEDS_REC,
+ .func = eprobe_trigger_cmd_func,
+ .reg = eprobe_trigger_reg_func,
+ .unreg = eprobe_trigger_unreg_func,
+ .unreg_all = NULL,
+ .get_trigger_ops = eprobe_trigger_get_ops,
+ .set_filter = NULL,
+};
+
+static struct event_trigger_data *
+new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file)
+{
+ struct event_trigger_data *trigger;
+ struct eprobe_data *edata;
+
+ edata = kzalloc(sizeof(*edata), GFP_KERNEL);
+ trigger = kzalloc(sizeof(*trigger), GFP_KERNEL);
+ if (!trigger || !edata) {
+ kfree(edata);
+ kfree(trigger);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ trigger->flags = EVENT_TRIGGER_FL_PROBE;
+ trigger->count = -1;
+ trigger->ops = &eprobe_trigger_ops;
+
+ /*
+ * EVENT PROBE triggers are not registered as commands with
+ * register_event_command(), as they are not controlled by the user
+ * from the trigger file
+ */
+ trigger->cmd_ops = &event_trigger_cmd;
+
+ INIT_LIST_HEAD(&trigger->list);
+ RCU_INIT_POINTER(trigger->filter, NULL);
+
+ edata->file = file;
+ edata->ep = ep;
+ trigger->private_data = edata;
+
+ return trigger;
+}
+
+static int enable_eprobe(struct trace_eprobe *ep,
+ struct trace_event_file *eprobe_file)
+{
+ struct event_trigger_data *trigger;
+ struct trace_event_file *file;
+ struct trace_array *tr = eprobe_file->tr;
+
+ file = find_event_file(tr, ep->event_system, ep->event_name);
+ if (!file)
+ return -ENOENT;
+ trigger = new_eprobe_trigger(ep, eprobe_file);
+ if (IS_ERR(trigger))
+ return PTR_ERR(trigger);
+
+ list_add_tail_rcu(&trigger->list, &file->triggers);
+
+ trace_event_trigger_enable_disable(file, 1);
+ update_cond_flag(file);
+
+ return 0;
+}
+
+static struct trace_event_functions eprobe_funcs = {
+ .trace = print_eprobe_event
+};
+
+static int disable_eprobe(struct trace_eprobe *ep,
+ struct trace_array *tr)
+{
+ struct event_trigger_data *trigger;
+ struct trace_event_file *file;
+ struct eprobe_data *edata;
+
+ file = find_event_file(tr, ep->event_system, ep->event_name);
+ if (!file)
+ return -ENOENT;
+
+ list_for_each_entry(trigger, &file->triggers, list) {
+ if (!(trigger->flags & EVENT_TRIGGER_FL_PROBE))
+ continue;
+ edata = trigger->private_data;
+ if (edata->ep == ep)
+ break;
+ }
+ if (list_entry_is_head(trigger, &file->triggers, list))
+ return -ENODEV;
+
+ list_del_rcu(&trigger->list);
+
+ trace_event_trigger_enable_disable(file, 0);
+ update_cond_flag(file);
+ return 0;
+}
+
+static int enable_trace_eprobe(struct trace_event_call *call,
+ struct trace_event_file *file)
+{
+ struct trace_probe *pos, *tp;
+ struct trace_eprobe *ep;
+ bool enabled;
+ int ret = 0;
+
+ tp = trace_probe_primary_from_call(call);
+ if (WARN_ON_ONCE(!tp))
+ return -ENODEV;
+ enabled = trace_probe_is_enabled(tp);
+
+ /* This also changes "enabled" state */
+ if (file) {
+ ret = trace_probe_add_file(tp, file);
+ if (ret)
+ return ret;
+ } else
+ trace_probe_set_flag(tp, TP_FLAG_PROFILE);
+
+ if (enabled)
+ return 0;
+
+ list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+ ep = container_of(pos, struct trace_eprobe, tp);
+ ret = enable_eprobe(ep, file);
+ if (ret)
+ break;
+ enabled = true;
+ }
+
+ if (ret) {
+ /* Failed to enable one of them. Roll back all */
+ if (enabled)
+ disable_eprobe(ep, file->tr);
+ if (file)
+ trace_probe_remove_file(tp, file);
+ else
+ trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+ }
+
+ return ret;
+}
+
+static int disable_trace_eprobe(struct trace_event_call *call,
+ struct trace_event_file *file)
+{
+ struct trace_probe *pos, *tp;
+ struct trace_eprobe *ep;
+
+ tp = trace_probe_primary_from_call(call);
+ if (WARN_ON_ONCE(!tp))
+ return -ENODEV;
+
+ if (file) {
+ if (!trace_probe_get_file_link(tp, file))
+ return -ENOENT;
+ if (!trace_probe_has_single_file(tp))
+ goto out;
+ trace_probe_clear_flag(tp, TP_FLAG_TRACE);
+ } else
+ trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+
+ if (!trace_probe_is_enabled(tp)) {
+ list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
+ ep = container_of(pos, struct trace_eprobe, tp);
+ disable_eprobe(ep, file->tr);
+ }
+ }
+
+ out:
+ if (file)
+ /*
+ * Synchronization is done in below function. For perf event,
+ * file == NULL and perf_trace_event_unreg() calls
+ * tracepoint_synchronize_unregister() to ensure synchronize
+ * event. We don't need to care about it.
+ */
+ trace_probe_remove_file(tp, file);
+
+ return 0;
+}
+
+static int eprobe_register(struct trace_event_call *event,
+ enum trace_reg type, void *data)
+{
+ struct trace_event_file *file = data;
+
+ switch (type) {
+ case TRACE_REG_REGISTER:
+ return enable_trace_eprobe(event, file);
+ case TRACE_REG_UNREGISTER:
+ return disable_trace_eprobe(event, file);
+#ifdef CONFIG_PERF_EVENTS
+ case TRACE_REG_PERF_REGISTER:
+ case TRACE_REG_PERF_UNREGISTER:
+ case TRACE_REG_PERF_OPEN:
+ case TRACE_REG_PERF_CLOSE:
+ case TRACE_REG_PERF_ADD:
+ case TRACE_REG_PERF_DEL:
+ return 0;
+#endif
+ }
+ return 0;
+}
+
+static inline void init_trace_eprobe_call(struct trace_eprobe *ep)
+{
+ struct trace_event_call *call = trace_probe_event_call(&ep->tp);
+
+ call->flags = TRACE_EVENT_FL_EPROBE;
+ call->event.funcs = &eprobe_funcs;
+ call->class->fields_array = eprobe_fields_array;
+ call->class->reg = eprobe_register;
+}
+
+static struct trace_event_call *
+find_and_get_event(const char *system, const char *event_name)
+{
+ struct trace_event_call *tp_event;
+ const char *name;
+
+ list_for_each_entry(tp_event, &ftrace_events, list) {
+ /* Skip other probes and ftrace events */
+ if (tp_event->flags &
+ (TRACE_EVENT_FL_IGNORE_ENABLE |
+ TRACE_EVENT_FL_KPROBE |
+ TRACE_EVENT_FL_UPROBE |
+ TRACE_EVENT_FL_EPROBE))
+ continue;
+ if (!tp_event->class->system ||
+ strcmp(system, tp_event->class->system))
+ continue;
+ name = trace_event_name(tp_event);
+ if (!name || strcmp(event_name, name))
+ continue;
+ if (!trace_event_try_get_ref(tp_event)) {
+ return NULL;
+ break;
+ }
+ return tp_event;
+ break;
+ }
+ return NULL;
+}
+
+static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i)
+{
+ unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_TPOINT;
+ int ret;
+
+ ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], flags);
+ if (ret)
+ return ret;
+
+ if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG)
+ ret = trace_eprobe_tp_arg_update(ep, i);
+
+ return ret;
+}
+
+static int __trace_eprobe_create(int argc, const char *argv[])
+{
+ /*
+ * Argument syntax:
+ * e[:[GRP/]ENAME] SYSTEM.EVENT [FETCHARGS]
+ * Fetch args:
+ * <name>=$<field>[:TYPE]
+ */
+ const char *event = NULL, *group = EPROBE_EVENT_SYSTEM;
+ const char *sys_event = NULL, *sys_name = NULL;
+ struct trace_event_call *event_call;
+ struct trace_eprobe *ep = NULL;
+ char buf1[MAX_EVENT_NAME_LEN];
+ char buf2[MAX_EVENT_NAME_LEN];
+ int ret = 0;
+ int i;
+
+ if (argc < 2 || argv[0][0] != 'e')
+ return -ECANCELED;
+
+ trace_probe_log_init("event_probe", argc, argv);
+
+ event = strchr(&argv[0][1], ':');
+ if (event) {
+ event++;
+ ret = traceprobe_parse_event_name(&event, &group, buf1,
+ event - argv[0]);
+ if (ret)
+ goto parse_error;
+ } else {
+ strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN);
+ sanitize_event_name(buf1);
+ event = buf1;
+ }
+ if (!is_good_name(event) || !is_good_name(group))
+ goto parse_error;
+
+ sys_event = argv[1];
+ ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2,
+ sys_event - argv[1]);
+ if (ret || !sys_name)
+ goto parse_error;
+ if (!is_good_name(sys_event) || !is_good_name(sys_name))
+ goto parse_error;
+
+ mutex_lock(&event_mutex);
+ event_call = find_and_get_event(sys_name, sys_event);
+ ep = alloc_event_probe(group, event, event_call, argc - 2);
+ mutex_unlock(&event_mutex);
+
+ if (IS_ERR(ep)) {
+ ret = PTR_ERR(ep);
+ /* This must return -ENOMEM, else there is a bug */
+ WARN_ON_ONCE(ret != -ENOMEM);
+ goto error; /* We know ep is not allocated */
+ }
+
+ argc -= 2; argv += 2;
+ /* parse arguments */
+ for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+ trace_probe_log_set_index(i + 2);
+ ret = trace_eprobe_tp_update_arg(ep, argv, i);
+ if (ret)
+ goto error;
+ }
+ ret = traceprobe_set_print_fmt(&ep->tp, PROBE_PRINT_EVENT);
+ if (ret < 0)
+ goto error;
+ init_trace_eprobe_call(ep);
+ mutex_lock(&event_mutex);
+ ret = trace_probe_register_event_call(&ep->tp);
+ if (ret) {
+ if (ret == -EEXIST) {
+ trace_probe_log_set_index(0);
+ trace_probe_log_err(0, EVENT_EXIST);
+ }
+ mutex_unlock(&event_mutex);
+ goto error;
+ }
+ ret = dyn_event_add(&ep->devent, &ep->tp.event->call);
+ mutex_unlock(&event_mutex);
+ return ret;
+parse_error:
+ ret = -EINVAL;
+error:
+ trace_event_probe_cleanup(ep);
+ return ret;
+}
+
+/*
+ * Register dynevent at core_initcall. This allows kernel to setup eprobe
+ * events in postcore_initcall without tracefs.
+ */
+static __init int trace_events_eprobe_init_early(void)
+{
+ int err = 0;
+
+ err = dyn_event_register(&eprobe_dyn_event_ops);
+ if (err)
+ pr_warn("Could not register eprobe_dyn_event_ops\n");
+
+ return err;
+}
+core_initcall(trace_events_eprobe_init_early);
projects / kernel.git / commitdiff