diff options
Diffstat (limited to '')
| -rw-r--r-- | kernel/trace/trace_eprobe.c | 1095 |
1 files changed, 1095 insertions, 0 deletions
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c new file mode 100644 index 000000000..d2370cdb4 --- /dev/null +++ b/kernel/trace/trace_eprobe.c @@ -0,0 +1,1095 @@ +// 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" +#include "trace_probe_kernel.h" + +#define EPROBE_EVENT_SYSTEM "eprobes" + +struct trace_eprobe { + /* tracepoint system */ + const char *event_system; + + /* tracepoint event */ + const char *event_name; + + /* filter string for the tracepoint */ + char *filter_str; + + 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->filter_str); + 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); + const char *slash; + + /* + * We match the following: + * event only - match all eprobes with event name + * system and event only - match all system/event probes + * system only - match all system probes + * + * The below has the above satisfied with more arguments: + * + * attached system/event - If the arg has the system and event + * the probe is attached to, match + * probes with the attachment. + * + * If any more args are given, then it requires a full match. + */ + + /* + * If system exists, but this probe is not part of that system + * do not match. + */ + if (system && strcmp(trace_probe_group_name(&ep->tp), system) != 0) + return false; + + /* Must match the event name */ + if (event[0] != '\0' && strcmp(trace_probe_name(&ep->tp), event) != 0) + return false; + + /* No arguments match all */ + if (argc < 1) + return true; + + /* First argument is the system/event the probe is attached to */ + + slash = strchr(argv[0], '/'); + if (!slash) + slash = strchr(argv[0], '.'); + if (!slash) + return false; + + if (strncmp(ep->event_system, argv[0], slash - argv[0])) + return false; + if (strcmp(ep->event_name, slash + 1)) + return false; + + argc--; + argv++; + + /* If there are no other args, then match */ + if (argc < 1) + return true; + + return 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(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; + int ret = -ENOENT; + + 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; + } + } + + /* + * Argument not found on event. But allow for comm and COMM + * to be used to get the current->comm. + */ + if (strcmp(parg->code->data, "COMM") == 0 || + strcmp(parg->code->data, "comm") == 0) { + parg->code->op = FETCH_OP_COMM; + ret = 0; + } + + kfree(parg->code->data); + parg->code->data = NULL; + return ret; +} + +static int eprobe_event_define_fields(struct trace_event_call *event_call) +{ + 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; + + 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_eprobe *ep; + struct trace_probe *tp; + unsigned int type; + + 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; + + ep = container_of(tp, struct trace_eprobe, tp); + type = ep->event->event.type; + + trace_seq_printf(s, "%s: (", trace_probe_name(tp)); + + probed_event = ftrace_find_event(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", 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; + + if (is_string_field(field)) { + switch (field->filter_type) { + case FILTER_DYN_STRING: + val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff)); + break; + case FILTER_RDYN_STRING: + val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff)); + break; + case FILTER_STATIC_STRING: + val = (unsigned long)addr; + break; + case FILTER_PTR_STRING: + val = (unsigned long)(*(char *)addr); + break; + default: + WARN_ON_ONCE(1); + return 0; + } + return val; + } + + 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 fetch_insn *code; + struct probe_arg *arg; + int i, len, ret = 0; + + for (i = 0; i < tp->nr_args; i++) { + arg = tp->args + i; + if (arg->dynamic) { + unsigned long val; + + code = arg->code; + retry: + switch (code->op) { + case FETCH_OP_TP_ARG: + val = get_event_field(code, rec); + break; + case FETCH_OP_IMM: + val = code->immediate; + break; + case FETCH_OP_COMM: + val = (unsigned long)current->comm; + break; + case FETCH_OP_DATA: + val = (unsigned long)code->data; + break; + case FETCH_NOP_SYMBOL: /* Ignore a place holder */ + code++; + goto retry; + default: + continue; + } + code++; + len = process_fetch_insn_bottom(code, 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; + + retry: + switch (code->op) { + case FETCH_OP_TP_ARG: + val = get_event_field(code, rec); + break; + case FETCH_OP_IMM: + val = code->immediate; + break; + case FETCH_OP_COMM: + val = (unsigned long)current->comm; + break; + case FETCH_OP_DATA: + val = (unsigned long)code->data; + break; + case FETCH_NOP_SYMBOL: /* Ignore a place holder */ + code++; + goto retry; + default: + return -EILSEQ; + } + code++; + return process_fetch_insn_bottom(code, 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) +{ + return kern_fetch_store_strlen_user(addr); +} + +/* Return the length of string -- including null terminal byte */ +static nokprobe_inline int +fetch_store_strlen(unsigned long addr) +{ + return kern_fetch_store_strlen(addr); +} + +/* + * 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) +{ + return kern_fetch_store_string_user(addr, dest, base); +} + +/* + * 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) +{ + return kern_fetch_store_string(addr, dest, base); +} + +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; + + dsize = get_eprobe_size(&edata->ep->tp, rec); + + entry = trace_event_buffer_reserve(&fbuffer, edata->file, + sizeof(*entry) + edata->ep->tp.size + dsize); + + if (!entry) + return; + + entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); + 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_data *data) +{ + return 0; +} + +static void eprobe_trigger_free(struct event_trigger_data *data) +{ + +} + +static int eprobe_trigger_print(struct seq_file *m, + 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; + + if (unlikely(!rec)) + return; + + if (unlikely(!rec)) + return; + + __eprobe_trace_func(edata, rec); +} + +static struct event_trigger_ops eprobe_trigger_ops = { + .trigger = eprobe_trigger_func, + .print = eprobe_trigger_print, + .init = eprobe_trigger_init, + .free = eprobe_trigger_free, +}; + +static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops, + struct trace_event_file *file, + char *glob, char *cmd, + char *param_and_filter) +{ + return -1; +} + +static int eprobe_trigger_reg_func(char *glob, + struct event_trigger_data *data, + struct trace_event_file *file) +{ + return -1; +} + +static void eprobe_trigger_unreg_func(char *glob, + 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, + .parse = eprobe_trigger_cmd_parse, + .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 event_filter *filter = NULL; + struct eprobe_data *edata; + int ret; + + edata = kzalloc(sizeof(*edata), GFP_KERNEL); + trigger = kzalloc(sizeof(*trigger), GFP_KERNEL); + if (!trigger || !edata) { + ret = -ENOMEM; + goto error; + } + + 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); + + if (ep->filter_str) { + ret = create_event_filter(file->tr, ep->event, + ep->filter_str, false, &filter); + if (ret) + goto error; + } + RCU_INIT_POINTER(trigger->filter, filter); + + edata->file = file; + edata->ep = ep; + trigger->private_data = edata; + + return trigger; +error: + free_event_filter(filter); + kfree(edata); + kfree(trigger); + return ERR_PTR(ret); +} + +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 = NULL, *iter; + struct trace_event_file *file; + struct event_filter *filter; + struct eprobe_data *edata; + + file = find_event_file(tr, ep->event_system, ep->event_name); + if (!file) + return -ENOENT; + + list_for_each_entry(iter, &file->triggers, list) { + if (!(iter->flags & EVENT_TRIGGER_FL_PROBE)) + continue; + edata = iter->private_data; + if (edata->ep == ep) { + trigger = iter; + break; + } + } + if (!trigger) + return -ENODEV; + + list_del_rcu(&trigger->list); + + trace_event_trigger_enable_disable(file, 0); + update_cond_flag(file); + + /* Make sure nothing is using the edata or trigger */ + tracepoint_synchronize_unregister(); + + filter = rcu_access_pointer(trigger->filter); + + if (filter) + free_event_filter(filter); + kfree(edata); + kfree(trigger); + + 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; + int cnt = 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; + cnt++; + } + + if (ret) { + /* Failed to enable one of them. Roll back all */ + if (enabled) { + /* + * It's a bug if one failed for something other than memory + * not being available but another eprobe succeeded. + */ + WARN_ON_ONCE(ret != -ENOMEM); + + list_for_each_entry(pos, trace_probe_probe_list(tp), list) { + ep = container_of(pos, struct trace_eprobe, tp); + disable_eprobe(ep, file->tr); + if (!--cnt) + break; + } + } + 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); + if (ret) + trace_probe_log_err(0, BAD_ATTACH_ARG); + } + + /* Handle symbols "@" */ + if (!ret) + ret = traceprobe_update_arg(&ep->tp.args[i]); + + return ret; +} + +static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[]) +{ + struct event_filter *dummy = NULL; + int i, ret, len = 0; + char *p; + + if (argc == 0) { + trace_probe_log_err(0, NO_EP_FILTER); + return -EINVAL; + } + + /* Recover the filter string */ + for (i = 0; i < argc; i++) + len += strlen(argv[i]) + 1; + + ep->filter_str = kzalloc(len, GFP_KERNEL); + if (!ep->filter_str) + return -ENOMEM; + + p = ep->filter_str; + for (i = 0; i < argc; i++) { + ret = snprintf(p, len, "%s ", argv[i]); + if (ret < 0) + goto error; + if (ret > len) { + ret = -E2BIG; + goto error; + } + p += ret; + len -= ret; + } + p[-1] = '\0'; + + /* + * Ensure the filter string can be parsed correctly. Note, this + * filter string is for the original event, not for the eprobe. + */ + ret = create_event_filter(top_trace_array(), ep->event, ep->filter_str, + true, &dummy); + free_event_filter(dummy); + if (ret) + goto error; + + return 0; +error: + kfree(ep->filter_str); + ep->filter_str = NULL; + return ret; +} + +static int __trace_eprobe_create(int argc, const char *argv[]) +{ + /* + * Argument syntax: + * e[:[GRP/][ENAME]] SYSTEM.EVENT [FETCHARGS] [if FILTER] + * Fetch args (no space): + * <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]; + char gbuf[MAX_EVENT_NAME_LEN]; + int ret = 0, filter_idx = 0; + int i, filter_cnt; + + 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, gbuf, + event - argv[0]); + if (ret) + goto parse_error; + } + + trace_probe_log_set_index(1); + sys_event = argv[1]; + ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0); + if (ret || !sys_event || !sys_name) { + trace_probe_log_err(0, NO_EVENT_INFO); + goto parse_error; + } + + if (!event) { + strscpy(buf1, sys_event, MAX_EVENT_NAME_LEN); + event = buf1; + } + + for (i = 2; i < argc; i++) { + if (!strcmp(argv[i], "if")) { + filter_idx = i + 1; + filter_cnt = argc - filter_idx; + argc = i; + break; + } + } + + 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); + if (ret == -ENODEV) + trace_probe_log_err(0, BAD_ATTACH_EVENT); + /* This must return -ENOMEM or missing event, else there is a bug */ + WARN_ON_ONCE(ret != -ENOMEM && ret != -ENODEV); + ep = NULL; + goto error; + } + + if (filter_idx) { + trace_probe_log_set_index(filter_idx); + ret = trace_eprobe_parse_filter(ep, filter_cnt, argv + filter_idx); + if (ret) + goto parse_error; + } else + ep->filter_str = NULL; + + 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); |