linux/kernel/trace/trace_events_synth.c
Steven Rostedt (Google) 0934ae9977 tracing: Fix reading strings from synthetic events
The follow commands caused a crash:

  # cd /sys/kernel/tracing
  # echo 's:open char file[]' > dynamic_events
  # echo 'hist:keys=common_pid:file=filename:onchange($file).trace(open,$file)' > events/syscalls/sys_enter_openat/trigger'
  # echo 1 > events/synthetic/open/enable

BOOM!

The problem is that the synthetic event field "char file[]" will read
the value given to it as a string without any memory checks to make sure
the address is valid. The above example will pass in the user space
address and the sythetic event code will happily call strlen() on it
and then strscpy() where either one will cause an oops when accessing
user space addresses.

Use the helper functions from trace_kprobe and trace_eprobe that can
read strings safely (and actually succeed when the address is from user
space and the memory is mapped in).

Now the above can show:

     packagekitd-1721    [000] ...2.   104.597170: open: file=/usr/lib/rpm/fileattrs/cmake.attr
    in:imjournal-978     [006] ...2.   104.599642: open: file=/var/lib/rsyslog/imjournal.state.tmp
     packagekitd-1721    [000] ...2.   104.626308: open: file=/usr/lib/rpm/fileattrs/debuginfo.attr

Link: https://lkml.kernel.org/r/20221012104534.826549315@goodmis.org

Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Fixes: bd82631d7c ("tracing: Add support for dynamic strings to synthetic events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-10-12 13:51:16 -04:00

2266 lines
54 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* trace_events_synth - synthetic trace events
*
* Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@linux.intel.com>
*/
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/security.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/stacktrace.h>
#include <linux/rculist.h>
#include <linux/tracefs.h>
/* for gfp flag names */
#include <linux/trace_events.h>
#include <trace/events/mmflags.h>
#include "trace_probe.h"
#include "trace_probe_kernel.h"
#include "trace_synth.h"
#undef ERRORS
#define ERRORS \
C(BAD_NAME, "Illegal name"), \
C(INVALID_CMD, "Command must be of the form: <name> field[;field] ..."),\
C(INVALID_DYN_CMD, "Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
C(EVENT_EXISTS, "Event already exists"), \
C(TOO_MANY_FIELDS, "Too many fields"), \
C(INCOMPLETE_TYPE, "Incomplete type"), \
C(INVALID_TYPE, "Invalid type"), \
C(INVALID_FIELD, "Invalid field"), \
C(INVALID_ARRAY_SPEC, "Invalid array specification"),
#undef C
#define C(a, b) SYNTH_ERR_##a
enum { ERRORS };
#undef C
#define C(a, b) b
static const char *err_text[] = { ERRORS };
static char *last_cmd;
static int errpos(const char *str)
{
if (!str || !last_cmd)
return 0;
return err_pos(last_cmd, str);
}
static void last_cmd_set(const char *str)
{
if (!str)
return;
kfree(last_cmd);
last_cmd = kstrdup(str, GFP_KERNEL);
}
static void synth_err(u8 err_type, u16 err_pos)
{
if (!last_cmd)
return;
tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
err_type, err_pos);
}
static int create_synth_event(const char *raw_command);
static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
static int synth_event_release(struct dyn_event *ev);
static bool synth_event_is_busy(struct dyn_event *ev);
static bool synth_event_match(const char *system, const char *event,
int argc, const char **argv, struct dyn_event *ev);
static struct dyn_event_operations synth_event_ops = {
.create = create_synth_event,
.show = synth_event_show,
.is_busy = synth_event_is_busy,
.free = synth_event_release,
.match = synth_event_match,
};
static bool is_synth_event(struct dyn_event *ev)
{
return ev->ops == &synth_event_ops;
}
static struct synth_event *to_synth_event(struct dyn_event *ev)
{
return container_of(ev, struct synth_event, devent);
}
static bool synth_event_is_busy(struct dyn_event *ev)
{
struct synth_event *event = to_synth_event(ev);
return event->ref != 0;
}
static bool synth_event_match(const char *system, const char *event,
int argc, const char **argv, struct dyn_event *ev)
{
struct synth_event *sev = to_synth_event(ev);
return strcmp(sev->name, event) == 0 &&
(!system || strcmp(system, SYNTH_SYSTEM) == 0);
}
struct synth_trace_event {
struct trace_entry ent;
u64 fields[];
};
static int synth_event_define_fields(struct trace_event_call *call)
{
struct synth_trace_event trace;
int offset = offsetof(typeof(trace), fields);
struct synth_event *event = call->data;
unsigned int i, size, n_u64;
char *name, *type;
bool is_signed;
int ret = 0;
for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
size = event->fields[i]->size;
is_signed = event->fields[i]->is_signed;
type = event->fields[i]->type;
name = event->fields[i]->name;
ret = trace_define_field(call, type, name, offset, size,
is_signed, FILTER_OTHER);
if (ret)
break;
event->fields[i]->offset = n_u64;
if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
offset += STR_VAR_LEN_MAX;
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
} else {
offset += sizeof(u64);
n_u64++;
}
}
event->n_u64 = n_u64;
return ret;
}
static bool synth_field_signed(char *type)
{
if (str_has_prefix(type, "u"))
return false;
if (strcmp(type, "gfp_t") == 0)
return false;
return true;
}
static int synth_field_is_string(char *type)
{
if (strstr(type, "char[") != NULL)
return true;
return false;
}
static int synth_field_string_size(char *type)
{
char buf[4], *end, *start;
unsigned int len;
int size, err;
start = strstr(type, "char[");
if (start == NULL)
return -EINVAL;
start += sizeof("char[") - 1;
end = strchr(type, ']');
if (!end || end < start || type + strlen(type) > end + 1)
return -EINVAL;
len = end - start;
if (len > 3)
return -EINVAL;
if (len == 0)
return 0; /* variable-length string */
strncpy(buf, start, len);
buf[len] = '\0';
err = kstrtouint(buf, 0, &size);
if (err)
return err;
if (size > STR_VAR_LEN_MAX)
return -EINVAL;
return size;
}
static int synth_field_size(char *type)
{
int size = 0;
if (strcmp(type, "s64") == 0)
size = sizeof(s64);
else if (strcmp(type, "u64") == 0)
size = sizeof(u64);
else if (strcmp(type, "s32") == 0)
size = sizeof(s32);
else if (strcmp(type, "u32") == 0)
size = sizeof(u32);
else if (strcmp(type, "s16") == 0)
size = sizeof(s16);
else if (strcmp(type, "u16") == 0)
size = sizeof(u16);
else if (strcmp(type, "s8") == 0)
size = sizeof(s8);
else if (strcmp(type, "u8") == 0)
size = sizeof(u8);
else if (strcmp(type, "char") == 0)
size = sizeof(char);
else if (strcmp(type, "unsigned char") == 0)
size = sizeof(unsigned char);
else if (strcmp(type, "int") == 0)
size = sizeof(int);
else if (strcmp(type, "unsigned int") == 0)
size = sizeof(unsigned int);
else if (strcmp(type, "long") == 0)
size = sizeof(long);
else if (strcmp(type, "unsigned long") == 0)
size = sizeof(unsigned long);
else if (strcmp(type, "bool") == 0)
size = sizeof(bool);
else if (strcmp(type, "pid_t") == 0)
size = sizeof(pid_t);
else if (strcmp(type, "gfp_t") == 0)
size = sizeof(gfp_t);
else if (synth_field_is_string(type))
size = synth_field_string_size(type);
return size;
}
static const char *synth_field_fmt(char *type)
{
const char *fmt = "%llu";
if (strcmp(type, "s64") == 0)
fmt = "%lld";
else if (strcmp(type, "u64") == 0)
fmt = "%llu";
else if (strcmp(type, "s32") == 0)
fmt = "%d";
else if (strcmp(type, "u32") == 0)
fmt = "%u";
else if (strcmp(type, "s16") == 0)
fmt = "%d";
else if (strcmp(type, "u16") == 0)
fmt = "%u";
else if (strcmp(type, "s8") == 0)
fmt = "%d";
else if (strcmp(type, "u8") == 0)
fmt = "%u";
else if (strcmp(type, "char") == 0)
fmt = "%d";
else if (strcmp(type, "unsigned char") == 0)
fmt = "%u";
else if (strcmp(type, "int") == 0)
fmt = "%d";
else if (strcmp(type, "unsigned int") == 0)
fmt = "%u";
else if (strcmp(type, "long") == 0)
fmt = "%ld";
else if (strcmp(type, "unsigned long") == 0)
fmt = "%lu";
else if (strcmp(type, "bool") == 0)
fmt = "%d";
else if (strcmp(type, "pid_t") == 0)
fmt = "%d";
else if (strcmp(type, "gfp_t") == 0)
fmt = "%x";
else if (synth_field_is_string(type))
fmt = "%.*s";
return fmt;
}
static void print_synth_event_num_val(struct trace_seq *s,
char *print_fmt, char *name,
int size, u64 val, char *space)
{
switch (size) {
case 1:
trace_seq_printf(s, print_fmt, name, (u8)val, space);
break;
case 2:
trace_seq_printf(s, print_fmt, name, (u16)val, space);
break;
case 4:
trace_seq_printf(s, print_fmt, name, (u32)val, space);
break;
default:
trace_seq_printf(s, print_fmt, name, val, space);
break;
}
}
static enum print_line_t print_synth_event(struct trace_iterator *iter,
int flags,
struct trace_event *event)
{
struct trace_array *tr = iter->tr;
struct trace_seq *s = &iter->seq;
struct synth_trace_event *entry;
struct synth_event *se;
unsigned int i, n_u64;
char print_fmt[32];
const char *fmt;
entry = (struct synth_trace_event *)iter->ent;
se = container_of(event, struct synth_event, call.event);
trace_seq_printf(s, "%s: ", se->name);
for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
if (trace_seq_has_overflowed(s))
goto end;
fmt = synth_field_fmt(se->fields[i]->type);
/* parameter types */
if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
trace_seq_printf(s, "%s ", fmt);
snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
/* parameter values */
if (se->fields[i]->is_string) {
if (se->fields[i]->is_dynamic) {
u32 offset, data_offset;
char *str_field;
offset = (u32)entry->fields[n_u64];
data_offset = offset & 0xffff;
str_field = (char *)entry + data_offset;
trace_seq_printf(s, print_fmt, se->fields[i]->name,
STR_VAR_LEN_MAX,
str_field,
i == se->n_fields - 1 ? "" : " ");
n_u64++;
} else {
trace_seq_printf(s, print_fmt, se->fields[i]->name,
STR_VAR_LEN_MAX,
(char *)&entry->fields[n_u64],
i == se->n_fields - 1 ? "" : " ");
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
}
} else {
struct trace_print_flags __flags[] = {
__def_gfpflag_names, {-1, NULL} };
char *space = (i == se->n_fields - 1 ? "" : " ");
print_synth_event_num_val(s, print_fmt,
se->fields[i]->name,
se->fields[i]->size,
entry->fields[n_u64],
space);
if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
trace_seq_puts(s, " (");
trace_print_flags_seq(s, "|",
entry->fields[n_u64],
__flags);
trace_seq_putc(s, ')');
}
n_u64++;
}
}
end:
trace_seq_putc(s, '\n');
return trace_handle_return(s);
}
static struct trace_event_functions synth_event_funcs = {
.trace = print_synth_event
};
static unsigned int trace_string(struct synth_trace_event *entry,
struct synth_event *event,
char *str_val,
bool is_dynamic,
unsigned int data_size,
unsigned int *n_u64)
{
unsigned int len = 0;
char *str_field;
int ret;
if (is_dynamic) {
u32 data_offset;
data_offset = offsetof(typeof(*entry), fields);
data_offset += event->n_u64 * sizeof(u64);
data_offset += data_size;
len = kern_fetch_store_strlen((unsigned long)str_val);
data_offset |= len << 16;
*(u32 *)&entry->fields[*n_u64] = data_offset;
ret = kern_fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
(*n_u64)++;
} else {
str_field = (char *)&entry->fields[*n_u64];
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
if ((unsigned long)str_val < TASK_SIZE)
ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
else
#endif
ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
if (ret < 0)
strcpy(str_field, FAULT_STRING);
(*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
}
return len;
}
static notrace void trace_event_raw_event_synth(void *__data,
u64 *var_ref_vals,
unsigned int *var_ref_idx)
{
unsigned int i, n_u64, val_idx, len, data_size = 0;
struct trace_event_file *trace_file = __data;
struct synth_trace_event *entry;
struct trace_event_buffer fbuffer;
struct trace_buffer *buffer;
struct synth_event *event;
int fields_size = 0;
event = trace_file->event_call->data;
if (trace_trigger_soft_disabled(trace_file))
return;
fields_size = event->n_u64 * sizeof(u64);
for (i = 0; i < event->n_dynamic_fields; i++) {
unsigned int field_pos = event->dynamic_fields[i]->field_pos;
char *str_val;
val_idx = var_ref_idx[field_pos];
str_val = (char *)(long)var_ref_vals[val_idx];
len = kern_fetch_store_strlen((unsigned long)str_val);
fields_size += len;
}
/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
buffer = trace_file->tr->array_buffer.buffer;
ring_buffer_nest_start(buffer);
entry = trace_event_buffer_reserve(&fbuffer, trace_file,
sizeof(*entry) + fields_size);
if (!entry)
goto out;
for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
val_idx = var_ref_idx[i];
if (event->fields[i]->is_string) {
char *str_val = (char *)(long)var_ref_vals[val_idx];
len = trace_string(entry, event, str_val,
event->fields[i]->is_dynamic,
data_size, &n_u64);
data_size += len; /* only dynamic string increments */
} else {
struct synth_field *field = event->fields[i];
u64 val = var_ref_vals[val_idx];
switch (field->size) {
case 1:
*(u8 *)&entry->fields[n_u64] = (u8)val;
break;
case 2:
*(u16 *)&entry->fields[n_u64] = (u16)val;
break;
case 4:
*(u32 *)&entry->fields[n_u64] = (u32)val;
break;
default:
entry->fields[n_u64] = val;
break;
}
n_u64++;
}
}
trace_event_buffer_commit(&fbuffer);
out:
ring_buffer_nest_end(buffer);
}
static void free_synth_event_print_fmt(struct trace_event_call *call)
{
if (call) {
kfree(call->print_fmt);
call->print_fmt = NULL;
}
}
static int __set_synth_event_print_fmt(struct synth_event *event,
char *buf, int len)
{
const char *fmt;
int pos = 0;
int i;
/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
for (i = 0; i < event->n_fields; i++) {
fmt = synth_field_fmt(event->fields[i]->type);
pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
event->fields[i]->name, fmt,
i == event->n_fields - 1 ? "" : ", ");
}
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
for (i = 0; i < event->n_fields; i++) {
if (event->fields[i]->is_string &&
event->fields[i]->is_dynamic)
pos += snprintf(buf + pos, LEN_OR_ZERO,
", __get_str(%s)", event->fields[i]->name);
else
pos += snprintf(buf + pos, LEN_OR_ZERO,
", REC->%s", event->fields[i]->name);
}
#undef LEN_OR_ZERO
/* return the length of print_fmt */
return pos;
}
static int set_synth_event_print_fmt(struct trace_event_call *call)
{
struct synth_event *event = call->data;
char *print_fmt;
int len;
/* First: called with 0 length to calculate the needed length */
len = __set_synth_event_print_fmt(event, NULL, 0);
print_fmt = kmalloc(len + 1, GFP_KERNEL);
if (!print_fmt)
return -ENOMEM;
/* Second: actually write the @print_fmt */
__set_synth_event_print_fmt(event, print_fmt, len + 1);
call->print_fmt = print_fmt;
return 0;
}
static void free_synth_field(struct synth_field *field)
{
kfree(field->type);
kfree(field->name);
kfree(field);
}
static int check_field_version(const char *prefix, const char *field_type,
const char *field_name)
{
/*
* For backward compatibility, the old synthetic event command
* format did not require semicolons, and in order to not
* break user space, that old format must still work. If a new
* feature is added, then the format that uses the new feature
* will be required to have semicolons, as nothing that uses
* the old format would be using the new, yet to be created,
* feature. When a new feature is added, this will detect it,
* and return a number greater than 1, and require the format
* to use semicolons.
*/
return 1;
}
static struct synth_field *parse_synth_field(int argc, char **argv,
int *consumed, int *field_version)
{
const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
struct synth_field *field;
int len, ret = -ENOMEM;
struct seq_buf s;
ssize_t size;
if (!strcmp(field_type, "unsigned")) {
if (argc < 3) {
synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
return ERR_PTR(-EINVAL);
}
prefix = "unsigned ";
field_type = argv[1];
field_name = argv[2];
*consumed += 3;
} else {
field_name = argv[1];
*consumed += 2;
}
if (!field_name) {
synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
return ERR_PTR(-EINVAL);
}
*field_version = check_field_version(prefix, field_type, field_name);
field = kzalloc(sizeof(*field), GFP_KERNEL);
if (!field)
return ERR_PTR(-ENOMEM);
len = strlen(field_name);
array = strchr(field_name, '[');
if (array)
len -= strlen(array);
field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
if (!field->name)
goto free;
if (!is_good_name(field->name)) {
synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
ret = -EINVAL;
goto free;
}
len = strlen(field_type) + 1;
if (array)
len += strlen(array);
if (prefix)
len += strlen(prefix);
field->type = kzalloc(len, GFP_KERNEL);
if (!field->type)
goto free;
seq_buf_init(&s, field->type, len);
if (prefix)
seq_buf_puts(&s, prefix);
seq_buf_puts(&s, field_type);
if (array)
seq_buf_puts(&s, array);
if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
goto free;
s.buffer[s.len] = '\0';
size = synth_field_size(field->type);
if (size < 0) {
if (array)
synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
else
synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
ret = -EINVAL;
goto free;
} else if (size == 0) {
if (synth_field_is_string(field->type)) {
char *type;
len = sizeof("__data_loc ") + strlen(field->type) + 1;
type = kzalloc(len, GFP_KERNEL);
if (!type)
goto free;
seq_buf_init(&s, type, len);
seq_buf_puts(&s, "__data_loc ");
seq_buf_puts(&s, field->type);
if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
goto free;
s.buffer[s.len] = '\0';
kfree(field->type);
field->type = type;
field->is_dynamic = true;
size = sizeof(u64);
} else {
synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
ret = -EINVAL;
goto free;
}
}
field->size = size;
if (synth_field_is_string(field->type))
field->is_string = true;
field->is_signed = synth_field_signed(field->type);
out:
return field;
free:
free_synth_field(field);
field = ERR_PTR(ret);
goto out;
}
static void free_synth_tracepoint(struct tracepoint *tp)
{
if (!tp)
return;
kfree(tp->name);
kfree(tp);
}
static struct tracepoint *alloc_synth_tracepoint(char *name)
{
struct tracepoint *tp;
tp = kzalloc(sizeof(*tp), GFP_KERNEL);
if (!tp)
return ERR_PTR(-ENOMEM);
tp->name = kstrdup(name, GFP_KERNEL);
if (!tp->name) {
kfree(tp);
return ERR_PTR(-ENOMEM);
}
return tp;
}
struct synth_event *find_synth_event(const char *name)
{
struct dyn_event *pos;
struct synth_event *event;
for_each_dyn_event(pos) {
if (!is_synth_event(pos))
continue;
event = to_synth_event(pos);
if (strcmp(event->name, name) == 0)
return event;
}
return NULL;
}
static struct trace_event_fields synth_event_fields_array[] = {
{ .type = TRACE_FUNCTION_TYPE,
.define_fields = synth_event_define_fields },
{}
};
static int register_synth_event(struct synth_event *event)
{
struct trace_event_call *call = &event->call;
int ret = 0;
event->call.class = &event->class;
event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
if (!event->class.system) {
ret = -ENOMEM;
goto out;
}
event->tp = alloc_synth_tracepoint(event->name);
if (IS_ERR(event->tp)) {
ret = PTR_ERR(event->tp);
event->tp = NULL;
goto out;
}
INIT_LIST_HEAD(&call->class->fields);
call->event.funcs = &synth_event_funcs;
call->class->fields_array = synth_event_fields_array;
ret = register_trace_event(&call->event);
if (!ret) {
ret = -ENODEV;
goto out;
}
call->flags = TRACE_EVENT_FL_TRACEPOINT;
call->class->reg = trace_event_reg;
call->class->probe = trace_event_raw_event_synth;
call->data = event;
call->tp = event->tp;
ret = trace_add_event_call(call);
if (ret) {
pr_warn("Failed to register synthetic event: %s\n",
trace_event_name(call));
goto err;
}
ret = set_synth_event_print_fmt(call);
if (ret < 0) {
trace_remove_event_call(call);
goto err;
}
out:
return ret;
err:
unregister_trace_event(&call->event);
goto out;
}
static int unregister_synth_event(struct synth_event *event)
{
struct trace_event_call *call = &event->call;
int ret;
ret = trace_remove_event_call(call);
return ret;
}
static void free_synth_event(struct synth_event *event)
{
unsigned int i;
if (!event)
return;
for (i = 0; i < event->n_fields; i++)
free_synth_field(event->fields[i]);
kfree(event->fields);
kfree(event->dynamic_fields);
kfree(event->name);
kfree(event->class.system);
free_synth_tracepoint(event->tp);
free_synth_event_print_fmt(&event->call);
kfree(event);
}
static struct synth_event *alloc_synth_event(const char *name, int n_fields,
struct synth_field **fields)
{
unsigned int i, j, n_dynamic_fields = 0;
struct synth_event *event;
event = kzalloc(sizeof(*event), GFP_KERNEL);
if (!event) {
event = ERR_PTR(-ENOMEM);
goto out;
}
event->name = kstrdup(name, GFP_KERNEL);
if (!event->name) {
kfree(event);
event = ERR_PTR(-ENOMEM);
goto out;
}
event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
if (!event->fields) {
free_synth_event(event);
event = ERR_PTR(-ENOMEM);
goto out;
}
for (i = 0; i < n_fields; i++)
if (fields[i]->is_dynamic)
n_dynamic_fields++;
if (n_dynamic_fields) {
event->dynamic_fields = kcalloc(n_dynamic_fields,
sizeof(*event->dynamic_fields),
GFP_KERNEL);
if (!event->dynamic_fields) {
free_synth_event(event);
event = ERR_PTR(-ENOMEM);
goto out;
}
}
dyn_event_init(&event->devent, &synth_event_ops);
for (i = 0, j = 0; i < n_fields; i++) {
fields[i]->field_pos = i;
event->fields[i] = fields[i];
if (fields[i]->is_dynamic)
event->dynamic_fields[j++] = fields[i];
}
event->n_dynamic_fields = j;
event->n_fields = n_fields;
out:
return event;
}
static int synth_event_check_arg_fn(void *data)
{
struct dynevent_arg_pair *arg_pair = data;
int size;
size = synth_field_size((char *)arg_pair->lhs);
if (size == 0) {
if (strstr((char *)arg_pair->lhs, "["))
return 0;
}
return size ? 0 : -EINVAL;
}
/**
* synth_event_add_field - Add a new field to a synthetic event cmd
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @type: The type of the new field to add
* @name: The name of the new field to add
*
* Add a new field to a synthetic event cmd object. Field ordering is in
* the same order the fields are added.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
const char *name)
{
struct dynevent_arg_pair arg_pair;
int ret;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
if (!type || !name)
return -EINVAL;
dynevent_arg_pair_init(&arg_pair, 0, ';');
arg_pair.lhs = type;
arg_pair.rhs = name;
ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
if (ret)
return ret;
if (++cmd->n_fields > SYNTH_FIELDS_MAX)
ret = -EINVAL;
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_add_field);
/**
* synth_event_add_field_str - Add a new field to a synthetic event cmd
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @type_name: The type and name of the new field to add, as a single string
*
* Add a new field to a synthetic event cmd object, as a single
* string. The @type_name string is expected to be of the form 'type
* name', which will be appended by ';'. No sanity checking is done -
* what's passed in is assumed to already be well-formed. Field
* ordering is in the same order the fields are added.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
{
struct dynevent_arg arg;
int ret;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
if (!type_name)
return -EINVAL;
dynevent_arg_init(&arg, ';');
arg.str = type_name;
ret = dynevent_arg_add(cmd, &arg, NULL);
if (ret)
return ret;
if (++cmd->n_fields > SYNTH_FIELDS_MAX)
ret = -EINVAL;
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_add_field_str);
/**
* synth_event_add_fields - Add multiple fields to a synthetic event cmd
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @fields: An array of type/name field descriptions
* @n_fields: The number of field descriptions contained in the fields array
*
* Add a new set of fields to a synthetic event cmd object. The event
* fields that will be defined for the event should be passed in as an
* array of struct synth_field_desc, and the number of elements in the
* array passed in as n_fields. Field ordering will retain the
* ordering given in the fields array.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_add_fields(struct dynevent_cmd *cmd,
struct synth_field_desc *fields,
unsigned int n_fields)
{
unsigned int i;
int ret = 0;
for (i = 0; i < n_fields; i++) {
if (fields[i].type == NULL || fields[i].name == NULL) {
ret = -EINVAL;
break;
}
ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
if (ret)
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_add_fields);
/**
* __synth_event_gen_cmd_start - Start a synthetic event command from arg list
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @name: The name of the synthetic event
* @mod: The module creating the event, NULL if not created from a module
* @args: Variable number of arg (pairs), one pair for each field
*
* NOTE: Users normally won't want to call this function directly, but
* rather use the synth_event_gen_cmd_start() wrapper, which
* automatically adds a NULL to the end of the arg list. If this
* function is used directly, make sure the last arg in the variable
* arg list is NULL.
*
* Generate a synthetic event command to be executed by
* synth_event_gen_cmd_end(). This function can be used to generate
* the complete command or only the first part of it; in the latter
* case, synth_event_add_field(), synth_event_add_field_str(), or
* synth_event_add_fields() can be used to add more fields following
* this.
*
* There should be an even number variable args, each pair consisting
* of a type followed by a field name.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
struct module *mod, ...)
{
struct dynevent_arg arg;
va_list args;
int ret;
cmd->event_name = name;
cmd->private_data = mod;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
dynevent_arg_init(&arg, 0);
arg.str = name;
ret = dynevent_arg_add(cmd, &arg, NULL);
if (ret)
return ret;
va_start(args, mod);
for (;;) {
const char *type, *name;
type = va_arg(args, const char *);
if (!type)
break;
name = va_arg(args, const char *);
if (!name)
break;
if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
ret = -EINVAL;
break;
}
ret = synth_event_add_field(cmd, type, name);
if (ret)
break;
}
va_end(args);
return ret;
}
EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
/**
* synth_event_gen_cmd_array_start - Start synthetic event command from an array
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @name: The name of the synthetic event
* @fields: An array of type/name field descriptions
* @n_fields: The number of field descriptions contained in the fields array
*
* Generate a synthetic event command to be executed by
* synth_event_gen_cmd_end(). This function can be used to generate
* the complete command or only the first part of it; in the latter
* case, synth_event_add_field(), synth_event_add_field_str(), or
* synth_event_add_fields() can be used to add more fields following
* this.
*
* The event fields that will be defined for the event should be
* passed in as an array of struct synth_field_desc, and the number of
* elements in the array passed in as n_fields. Field ordering will
* retain the ordering given in the fields array.
*
* See synth_field_size() for available types. If field_name contains
* [n] the field is considered to be an array.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
struct module *mod,
struct synth_field_desc *fields,
unsigned int n_fields)
{
struct dynevent_arg arg;
unsigned int i;
int ret = 0;
cmd->event_name = name;
cmd->private_data = mod;
if (cmd->type != DYNEVENT_TYPE_SYNTH)
return -EINVAL;
if (n_fields > SYNTH_FIELDS_MAX)
return -EINVAL;
dynevent_arg_init(&arg, 0);
arg.str = name;
ret = dynevent_arg_add(cmd, &arg, NULL);
if (ret)
return ret;
for (i = 0; i < n_fields; i++) {
if (fields[i].type == NULL || fields[i].name == NULL)
return -EINVAL;
ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
if (ret)
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
static int __create_synth_event(const char *name, const char *raw_fields)
{
char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
int consumed, cmd_version = 1, n_fields_this_loop;
int i, argc, n_fields = 0, ret = 0;
struct synth_event *event = NULL;
/*
* Argument syntax:
* - Add synthetic event: <event_name> field[;field] ...
* - Remove synthetic event: !<event_name> field[;field] ...
* where 'field' = type field_name
*/
if (name[0] == '\0') {
synth_err(SYNTH_ERR_INVALID_CMD, 0);
return -EINVAL;
}
if (!is_good_name(name)) {
synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
return -EINVAL;
}
mutex_lock(&event_mutex);
event = find_synth_event(name);
if (event) {
synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
ret = -EEXIST;
goto err;
}
tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
if (!tmp_fields) {
ret = -ENOMEM;
goto err;
}
while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
argv = argv_split(GFP_KERNEL, field_str, &argc);
if (!argv) {
ret = -ENOMEM;
goto err;
}
if (!argc) {
argv_free(argv);
continue;
}
n_fields_this_loop = 0;
consumed = 0;
while (argc > consumed) {
int field_version;
field = parse_synth_field(argc - consumed,
argv + consumed, &consumed,
&field_version);
if (IS_ERR(field)) {
ret = PTR_ERR(field);
goto err_free_arg;
}
/*
* Track the highest version of any field we
* found in the command.
*/
if (field_version > cmd_version)
cmd_version = field_version;
/*
* Now sort out what is and isn't valid for
* each supported version.
*
* If we see more than 1 field per loop, it
* means we have multiple fields between
* semicolons, and that's something we no
* longer support in a version 2 or greater
* command.
*/
if (cmd_version > 1 && n_fields_this_loop >= 1) {
synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
ret = -EINVAL;
goto err_free_arg;
}
fields[n_fields++] = field;
if (n_fields == SYNTH_FIELDS_MAX) {
synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
ret = -EINVAL;
goto err_free_arg;
}
n_fields_this_loop++;
}
argv_free(argv);
if (consumed < argc) {
synth_err(SYNTH_ERR_INVALID_CMD, 0);
ret = -EINVAL;
goto err;
}
}
if (n_fields == 0) {
synth_err(SYNTH_ERR_INVALID_CMD, 0);
ret = -EINVAL;
goto err;
}
event = alloc_synth_event(name, n_fields, fields);
if (IS_ERR(event)) {
ret = PTR_ERR(event);
event = NULL;
goto err;
}
ret = register_synth_event(event);
if (!ret)
dyn_event_add(&event->devent, &event->call);
else
free_synth_event(event);
out:
mutex_unlock(&event_mutex);
kfree(saved_fields);
return ret;
err_free_arg:
argv_free(argv);
err:
for (i = 0; i < n_fields; i++)
free_synth_field(fields[i]);
goto out;
}
/**
* synth_event_create - Create a new synthetic event
* @name: The name of the new synthetic event
* @fields: An array of type/name field descriptions
* @n_fields: The number of field descriptions contained in the fields array
* @mod: The module creating the event, NULL if not created from a module
*
* Create a new synthetic event with the given name under the
* trace/events/synthetic/ directory. The event fields that will be
* defined for the event should be passed in as an array of struct
* synth_field_desc, and the number elements in the array passed in as
* n_fields. Field ordering will retain the ordering given in the
* fields array.
*
* If the new synthetic event is being created from a module, the mod
* param must be non-NULL. This will ensure that the trace buffer
* won't contain unreadable events.
*
* The new synth event should be deleted using synth_event_delete()
* function. The new synthetic event can be generated from modules or
* other kernel code using trace_synth_event() and related functions.
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_create(const char *name, struct synth_field_desc *fields,
unsigned int n_fields, struct module *mod)
{
struct dynevent_cmd cmd;
char *buf;
int ret;
buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
if (!buf)
return -ENOMEM;
synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
fields, n_fields);
if (ret)
goto out;
ret = synth_event_gen_cmd_end(&cmd);
out:
kfree(buf);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_create);
static int destroy_synth_event(struct synth_event *se)
{
int ret;
if (se->ref)
return -EBUSY;
if (trace_event_dyn_busy(&se->call))
return -EBUSY;
ret = unregister_synth_event(se);
if (!ret) {
dyn_event_remove(&se->devent);
free_synth_event(se);
}
return ret;
}
/**
* synth_event_delete - Delete a synthetic event
* @event_name: The name of the new synthetic event
*
* Delete a synthetic event that was created with synth_event_create().
*
* Return: 0 if successful, error otherwise.
*/
int synth_event_delete(const char *event_name)
{
struct synth_event *se = NULL;
struct module *mod = NULL;
int ret = -ENOENT;
mutex_lock(&event_mutex);
se = find_synth_event(event_name);
if (se) {
mod = se->mod;
ret = destroy_synth_event(se);
}
mutex_unlock(&event_mutex);
if (mod) {
mutex_lock(&trace_types_lock);
/*
* It is safest to reset the ring buffer if the module
* being unloaded registered any events that were
* used. The only worry is if a new module gets
* loaded, and takes on the same id as the events of
* this module. When printing out the buffer, traced
* events left over from this module may be passed to
* the new module events and unexpected results may
* occur.
*/
tracing_reset_all_online_cpus();
mutex_unlock(&trace_types_lock);
}
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_delete);
static int check_command(const char *raw_command)
{
char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
int argc, ret = 0;
cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
if (!cmd)
return -ENOMEM;
name_and_field = strsep(&cmd, ";");
if (!name_and_field) {
ret = -EINVAL;
goto free;
}
if (name_and_field[0] == '!')
goto free;
argv = argv_split(GFP_KERNEL, name_and_field, &argc);
if (!argv) {
ret = -ENOMEM;
goto free;
}
argv_free(argv);
if (argc < 3)
ret = -EINVAL;
free:
kfree(saved_cmd);
return ret;
}
static int create_or_delete_synth_event(const char *raw_command)
{
char *name = NULL, *fields, *p;
int ret = 0;
raw_command = skip_spaces(raw_command);
if (raw_command[0] == '\0')
return ret;
last_cmd_set(raw_command);
ret = check_command(raw_command);
if (ret) {
synth_err(SYNTH_ERR_INVALID_CMD, 0);
return ret;
}
p = strpbrk(raw_command, " \t");
if (!p && raw_command[0] != '!') {
synth_err(SYNTH_ERR_INVALID_CMD, 0);
ret = -EINVAL;
goto free;
}
name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
if (!name)
return -ENOMEM;
if (name[0] == '!') {
ret = synth_event_delete(name + 1);
goto free;
}
fields = skip_spaces(p);
ret = __create_synth_event(name, fields);
free:
kfree(name);
return ret;
}
static int synth_event_run_command(struct dynevent_cmd *cmd)
{
struct synth_event *se;
int ret;
ret = create_or_delete_synth_event(cmd->seq.buffer);
if (ret)
return ret;
se = find_synth_event(cmd->event_name);
if (WARN_ON(!se))
return -ENOENT;
se->mod = cmd->private_data;
return ret;
}
/**
* synth_event_cmd_init - Initialize a synthetic event command object
* @cmd: A pointer to the dynevent_cmd struct representing the new event
* @buf: A pointer to the buffer used to build the command
* @maxlen: The length of the buffer passed in @buf
*
* Initialize a synthetic event command object. Use this before
* calling any of the other dyenvent_cmd functions.
*/
void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
{
dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
synth_event_run_command);
}
EXPORT_SYMBOL_GPL(synth_event_cmd_init);
static inline int
__synth_event_trace_init(struct trace_event_file *file,
struct synth_event_trace_state *trace_state)
{
int ret = 0;
memset(trace_state, '\0', sizeof(*trace_state));
/*
* Normal event tracing doesn't get called at all unless the
* ENABLED bit is set (which attaches the probe thus allowing
* this code to be called, etc). Because this is called
* directly by the user, we don't have that but we still need
* to honor not logging when disabled. For the iterated
* trace case, we save the enabled state upon start and just
* ignore the following data calls.
*/
if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
trace_trigger_soft_disabled(file)) {
trace_state->disabled = true;
ret = -ENOENT;
goto out;
}
trace_state->event = file->event_call->data;
out:
return ret;
}
static inline int
__synth_event_trace_start(struct trace_event_file *file,
struct synth_event_trace_state *trace_state,
int dynamic_fields_size)
{
int entry_size, fields_size = 0;
int ret = 0;
fields_size = trace_state->event->n_u64 * sizeof(u64);
fields_size += dynamic_fields_size;
/*
* Avoid ring buffer recursion detection, as this event
* is being performed within another event.
*/
trace_state->buffer = file->tr->array_buffer.buffer;
ring_buffer_nest_start(trace_state->buffer);
entry_size = sizeof(*trace_state->entry) + fields_size;
trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
file,
entry_size);
if (!trace_state->entry) {
ring_buffer_nest_end(trace_state->buffer);
ret = -EINVAL;
}
return ret;
}
static inline void
__synth_event_trace_end(struct synth_event_trace_state *trace_state)
{
trace_event_buffer_commit(&trace_state->fbuffer);
ring_buffer_nest_end(trace_state->buffer);
}
/**
* synth_event_trace - Trace a synthetic event
* @file: The trace_event_file representing the synthetic event
* @n_vals: The number of values in vals
* @args: Variable number of args containing the event values
*
* Trace a synthetic event using the values passed in the variable
* argument list.
*
* The argument list should be a list 'n_vals' u64 values. The number
* of vals must match the number of field in the synthetic event, and
* must be in the same order as the synthetic event fields.
*
* All vals should be cast to u64, and string vals are just pointers
* to strings, cast to u64. Strings will be copied into space
* reserved in the event for the string, using these pointers.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
{
unsigned int i, n_u64, len, data_size = 0;
struct synth_event_trace_state state;
va_list args;
int ret;
ret = __synth_event_trace_init(file, &state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}
if (state.event->n_dynamic_fields) {
va_start(args, n_vals);
for (i = 0; i < state.event->n_fields; i++) {
u64 val = va_arg(args, u64);
if (state.event->fields[i]->is_string &&
state.event->fields[i]->is_dynamic) {
char *str_val = (char *)(long)val;
data_size += strlen(str_val) + 1;
}
}
va_end(args);
}
ret = __synth_event_trace_start(file, &state, data_size);
if (ret)
return ret;
if (n_vals != state.event->n_fields) {
ret = -EINVAL;
goto out;
}
data_size = 0;
va_start(args, n_vals);
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
u64 val;
val = va_arg(args, u64);
if (state.event->fields[i]->is_string) {
char *str_val = (char *)(long)val;
len = trace_string(state.entry, state.event, str_val,
state.event->fields[i]->is_dynamic,
data_size, &n_u64);
data_size += len; /* only dynamic string increments */
} else {
struct synth_field *field = state.event->fields[i];
switch (field->size) {
case 1:
*(u8 *)&state.entry->fields[n_u64] = (u8)val;
break;
case 2:
*(u16 *)&state.entry->fields[n_u64] = (u16)val;
break;
case 4:
*(u32 *)&state.entry->fields[n_u64] = (u32)val;
break;
default:
state.entry->fields[n_u64] = val;
break;
}
n_u64++;
}
}
va_end(args);
out:
__synth_event_trace_end(&state);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_trace);
/**
* synth_event_trace_array - Trace a synthetic event from an array
* @file: The trace_event_file representing the synthetic event
* @vals: Array of values
* @n_vals: The number of values in vals
*
* Trace a synthetic event using the values passed in as 'vals'.
*
* The 'vals' array is just an array of 'n_vals' u64. The number of
* vals must match the number of field in the synthetic event, and
* must be in the same order as the synthetic event fields.
*
* All vals should be cast to u64, and string vals are just pointers
* to strings, cast to u64. Strings will be copied into space
* reserved in the event for the string, using these pointers.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
unsigned int n_vals)
{
unsigned int i, n_u64, field_pos, len, data_size = 0;
struct synth_event_trace_state state;
char *str_val;
int ret;
ret = __synth_event_trace_init(file, &state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}
if (state.event->n_dynamic_fields) {
for (i = 0; i < state.event->n_dynamic_fields; i++) {
field_pos = state.event->dynamic_fields[i]->field_pos;
str_val = (char *)(long)vals[field_pos];
len = strlen(str_val) + 1;
data_size += len;
}
}
ret = __synth_event_trace_start(file, &state, data_size);
if (ret)
return ret;
if (n_vals != state.event->n_fields) {
ret = -EINVAL;
goto out;
}
data_size = 0;
for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
if (state.event->fields[i]->is_string) {
char *str_val = (char *)(long)vals[i];
len = trace_string(state.entry, state.event, str_val,
state.event->fields[i]->is_dynamic,
data_size, &n_u64);
data_size += len; /* only dynamic string increments */
} else {
struct synth_field *field = state.event->fields[i];
u64 val = vals[i];
switch (field->size) {
case 1:
*(u8 *)&state.entry->fields[n_u64] = (u8)val;
break;
case 2:
*(u16 *)&state.entry->fields[n_u64] = (u16)val;
break;
case 4:
*(u32 *)&state.entry->fields[n_u64] = (u32)val;
break;
default:
state.entry->fields[n_u64] = val;
break;
}
n_u64++;
}
}
out:
__synth_event_trace_end(&state);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_trace_array);
/**
* synth_event_trace_start - Start piecewise synthetic event trace
* @file: The trace_event_file representing the synthetic event
* @trace_state: A pointer to object tracking the piecewise trace state
*
* Start the trace of a synthetic event field-by-field rather than all
* at once.
*
* This function 'opens' an event trace, which means space is reserved
* for the event in the trace buffer, after which the event's
* individual field values can be set through either
* synth_event_add_next_val() or synth_event_add_val().
*
* A pointer to a trace_state object is passed in, which will keep
* track of the current event trace state until the event trace is
* closed (and the event finally traced) using
* synth_event_trace_end().
*
* Note that synth_event_trace_end() must be called after all values
* have been added for each event trace, regardless of whether adding
* all field values succeeded or not.
*
* Note also that for a given event trace, all fields must be added
* using either synth_event_add_next_val() or synth_event_add_val()
* but not both together or interleaved.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace_start(struct trace_event_file *file,
struct synth_event_trace_state *trace_state)
{
int ret;
if (!trace_state)
return -EINVAL;
ret = __synth_event_trace_init(file, trace_state);
if (ret) {
if (ret == -ENOENT)
ret = 0; /* just disabled, not really an error */
return ret;
}
if (trace_state->event->n_dynamic_fields)
return -ENOTSUPP;
ret = __synth_event_trace_start(file, trace_state, 0);
return ret;
}
EXPORT_SYMBOL_GPL(synth_event_trace_start);
static int __synth_event_add_val(const char *field_name, u64 val,
struct synth_event_trace_state *trace_state)
{
struct synth_field *field = NULL;
struct synth_trace_event *entry;
struct synth_event *event;
int i, ret = 0;
if (!trace_state) {
ret = -EINVAL;
goto out;
}
/* can't mix add_next_synth_val() with add_synth_val() */
if (field_name) {
if (trace_state->add_next) {
ret = -EINVAL;
goto out;
}
trace_state->add_name = true;
} else {
if (trace_state->add_name) {
ret = -EINVAL;
goto out;
}
trace_state->add_next = true;
}
if (trace_state->disabled)
goto out;
event = trace_state->event;
if (trace_state->add_name) {
for (i = 0; i < event->n_fields; i++) {
field = event->fields[i];
if (strcmp(field->name, field_name) == 0)
break;
}
if (!field) {
ret = -EINVAL;
goto out;
}
} else {
if (trace_state->cur_field >= event->n_fields) {
ret = -EINVAL;
goto out;
}
field = event->fields[trace_state->cur_field++];
}
entry = trace_state->entry;
if (field->is_string) {
char *str_val = (char *)(long)val;
char *str_field;
if (field->is_dynamic) { /* add_val can't do dynamic strings */
ret = -EINVAL;
goto out;
}
if (!str_val) {
ret = -EINVAL;
goto out;
}
str_field = (char *)&entry->fields[field->offset];
strscpy(str_field, str_val, STR_VAR_LEN_MAX);
} else {
switch (field->size) {
case 1:
*(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
break;
case 2:
*(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
break;
case 4:
*(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
break;
default:
trace_state->entry->fields[field->offset] = val;
break;
}
}
out:
return ret;
}
/**
* synth_event_add_next_val - Add the next field's value to an open synth trace
* @val: The value to set the next field to
* @trace_state: A pointer to object tracking the piecewise trace state
*
* Set the value of the next field in an event that's been opened by
* synth_event_trace_start().
*
* The val param should be the value cast to u64. If the value points
* to a string, the val param should be a char * cast to u64.
*
* This function assumes all the fields in an event are to be set one
* after another - successive calls to this function are made, one for
* each field, in the order of the fields in the event, until all
* fields have been set. If you'd rather set each field individually
* without regard to ordering, synth_event_add_val() can be used
* instead.
*
* Note however that synth_event_add_next_val() and
* synth_event_add_val() can't be intermixed for a given event trace -
* one or the other but not both can be used at the same time.
*
* Note also that synth_event_trace_end() must be called after all
* values have been added for each event trace, regardless of whether
* adding all field values succeeded or not.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_add_next_val(u64 val,
struct synth_event_trace_state *trace_state)
{
return __synth_event_add_val(NULL, val, trace_state);
}
EXPORT_SYMBOL_GPL(synth_event_add_next_val);
/**
* synth_event_add_val - Add a named field's value to an open synth trace
* @field_name: The name of the synthetic event field value to set
* @val: The value to set the named field to
* @trace_state: A pointer to object tracking the piecewise trace state
*
* Set the value of the named field in an event that's been opened by
* synth_event_trace_start().
*
* The val param should be the value cast to u64. If the value points
* to a string, the val param should be a char * cast to u64.
*
* This function looks up the field name, and if found, sets the field
* to the specified value. This lookup makes this function more
* expensive than synth_event_add_next_val(), so use that or the
* none-piecewise synth_event_trace() instead if efficiency is more
* important.
*
* Note however that synth_event_add_next_val() and
* synth_event_add_val() can't be intermixed for a given event trace -
* one or the other but not both can be used at the same time.
*
* Note also that synth_event_trace_end() must be called after all
* values have been added for each event trace, regardless of whether
* adding all field values succeeded or not.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_add_val(const char *field_name, u64 val,
struct synth_event_trace_state *trace_state)
{
return __synth_event_add_val(field_name, val, trace_state);
}
EXPORT_SYMBOL_GPL(synth_event_add_val);
/**
* synth_event_trace_end - End piecewise synthetic event trace
* @trace_state: A pointer to object tracking the piecewise trace state
*
* End the trace of a synthetic event opened by
* synth_event_trace__start().
*
* This function 'closes' an event trace, which basically means that
* it commits the reserved event and cleans up other loose ends.
*
* A pointer to a trace_state object is passed in, which will keep
* track of the current event trace state opened with
* synth_event_trace_start().
*
* Note that this function must be called after all values have been
* added for each event trace, regardless of whether adding all field
* values succeeded or not.
*
* Return: 0 on success, err otherwise.
*/
int synth_event_trace_end(struct synth_event_trace_state *trace_state)
{
if (!trace_state)
return -EINVAL;
__synth_event_trace_end(trace_state);
return 0;
}
EXPORT_SYMBOL_GPL(synth_event_trace_end);
static int create_synth_event(const char *raw_command)
{
char *fields, *p;
const char *name;
int len, ret = 0;
raw_command = skip_spaces(raw_command);
if (raw_command[0] == '\0')
return ret;
last_cmd_set(raw_command);
name = raw_command;
/* Don't try to process if not our system */
if (name[0] != 's' || name[1] != ':')
return -ECANCELED;
name += 2;
p = strpbrk(raw_command, " \t");
if (!p) {
synth_err(SYNTH_ERR_INVALID_CMD, 0);
return -EINVAL;
}
fields = skip_spaces(p);
/* This interface accepts group name prefix */
if (strchr(name, '/')) {
len = str_has_prefix(name, SYNTH_SYSTEM "/");
if (len == 0) {
synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
return -EINVAL;
}
name += len;
}
len = name - raw_command;
ret = check_command(raw_command + len);
if (ret) {
synth_err(SYNTH_ERR_INVALID_CMD, 0);
return ret;
}
name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
if (!name)
return -ENOMEM;
ret = __create_synth_event(name, fields);
kfree(name);
return ret;
}
static int synth_event_release(struct dyn_event *ev)
{
struct synth_event *event = to_synth_event(ev);
int ret;
if (event->ref)
return -EBUSY;
if (trace_event_dyn_busy(&event->call))
return -EBUSY;
ret = unregister_synth_event(event);
if (ret)
return ret;
dyn_event_remove(ev);
free_synth_event(event);
return 0;
}
static int __synth_event_show(struct seq_file *m, struct synth_event *event)
{
struct synth_field *field;
unsigned int i;
char *type, *t;
seq_printf(m, "%s\t", event->name);
for (i = 0; i < event->n_fields; i++) {
field = event->fields[i];
type = field->type;
t = strstr(type, "__data_loc");
if (t) { /* __data_loc belongs in format but not event desc */
t += sizeof("__data_loc");
type = t;
}
/* parameter values */
seq_printf(m, "%s %s%s", type, field->name,
i == event->n_fields - 1 ? "" : "; ");
}
seq_putc(m, '\n');
return 0;
}
static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
{
struct synth_event *event = to_synth_event(ev);
seq_printf(m, "s:%s/", event->class.system);
return __synth_event_show(m, event);
}
static int synth_events_seq_show(struct seq_file *m, void *v)
{
struct dyn_event *ev = v;
if (!is_synth_event(ev))
return 0;
return __synth_event_show(m, to_synth_event(ev));
}
static const struct seq_operations synth_events_seq_op = {
.start = dyn_event_seq_start,
.next = dyn_event_seq_next,
.stop = dyn_event_seq_stop,
.show = synth_events_seq_show,
};
static int synth_events_open(struct inode *inode, struct file *file)
{
int ret;
ret = security_locked_down(LOCKDOWN_TRACEFS);
if (ret)
return ret;
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
ret = dyn_events_release_all(&synth_event_ops);
if (ret < 0)
return ret;
}
return seq_open(file, &synth_events_seq_op);
}
static ssize_t synth_events_write(struct file *file,
const char __user *buffer,
size_t count, loff_t *ppos)
{
return trace_parse_run_command(file, buffer, count, ppos,
create_or_delete_synth_event);
}
static const struct file_operations synth_events_fops = {
.open = synth_events_open,
.write = synth_events_write,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
/*
* Register dynevent at core_initcall. This allows kernel to setup kprobe
* events in postcore_initcall without tracefs.
*/
static __init int trace_events_synth_init_early(void)
{
int err = 0;
err = dyn_event_register(&synth_event_ops);
if (err)
pr_warn("Could not register synth_event_ops\n");
return err;
}
core_initcall(trace_events_synth_init_early);
static __init int trace_events_synth_init(void)
{
struct dentry *entry = NULL;
int err = 0;
err = tracing_init_dentry();
if (err)
goto err;
entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
NULL, NULL, &synth_events_fops);
if (!entry) {
err = -ENODEV;
goto err;
}
return err;
err:
pr_warn("Could not create tracefs 'synthetic_events' entry\n");
return err;
}
fs_initcall(trace_events_synth_init);