Linux-2.6.33.2/kernel/trace/trace_events_filter.c
/*
* trace_events_filter - generic event filtering
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
*/
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/mutex.h>
#include <linux/perf_event.h>
#include "trace.h"
#include "trace_output.h"
enum filter_op_ids
{
OP_OR,
OP_AND,
OP_GLOB,
OP_NE,
OP_EQ,
OP_LT,
OP_LE,
OP_GT,
OP_GE,
OP_NONE,
OP_OPEN_PAREN,
};
struct filter_op {
int id;
char *string;
int precedence;
};
static struct filter_op filter_ops[] = {
{ OP_OR, "||", 1 },
{ OP_AND, "&&", 2 },
{ OP_GLOB, "~", 4 },
{ OP_NE, "!=", 4 },
{ OP_EQ, "==", 4 },
{ OP_LT, "<", 5 },
{ OP_LE, "<=", 5 },
{ OP_GT, ">", 5 },
{ OP_GE, ">=", 5 },
{ OP_NONE, "OP_NONE", 0 },
{ OP_OPEN_PAREN, "(", 0 },
};
enum {
FILT_ERR_NONE,
FILT_ERR_INVALID_OP,
FILT_ERR_UNBALANCED_PAREN,
FILT_ERR_TOO_MANY_OPERANDS,
FILT_ERR_OPERAND_TOO_LONG,
FILT_ERR_FIELD_NOT_FOUND,
FILT_ERR_ILLEGAL_FIELD_OP,
FILT_ERR_ILLEGAL_INTVAL,
FILT_ERR_BAD_SUBSYS_FILTER,
FILT_ERR_TOO_MANY_PREDS,
FILT_ERR_MISSING_FIELD,
FILT_ERR_INVALID_FILTER,
};
static char *err_text[] = {
"No error",
"Invalid operator",
"Unbalanced parens",
"Too many operands",
"Operand too long",
"Field not found",
"Illegal operation for field type",
"Illegal integer value",
"Couldn't find or set field in one of a subsystem's events",
"Too many terms in predicate expression",
"Missing field name and/or value",
"Meaningless filter expression",
};
struct opstack_op {
int op;
struct list_head list;
};
struct postfix_elt {
int op;
char *operand;
struct list_head list;
};
struct filter_parse_state {
struct filter_op *ops;
struct list_head opstack;
struct list_head postfix;
int lasterr;
int lasterr_pos;
struct {
char *string;
unsigned int cnt;
unsigned int tail;
} infix;
struct {
char string[MAX_FILTER_STR_VAL];
int pos;
unsigned int tail;
} operand;
};
#define DEFINE_COMPARISON_PRED(type) \
static int filter_pred_##type(struct filter_pred *pred, void *event, \
int val1, int val2) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
int match = 0; \
\
switch (pred->op) { \
case OP_LT: \
match = (*addr < val); \
break; \
case OP_LE: \
match = (*addr <= val); \
break; \
case OP_GT: \
match = (*addr > val); \
break; \
case OP_GE: \
match = (*addr >= val); \
break; \
default: \
break; \
} \
\
return match; \
}
#define DEFINE_EQUALITY_PRED(size) \
static int filter_pred_##size(struct filter_pred *pred, void *event, \
int val1, int val2) \
{ \
u##size *addr = (u##size *)(event + pred->offset); \
u##size val = (u##size)pred->val; \
int match; \
\
match = (val == *addr) ^ pred->not; \
\
return match; \
}
DEFINE_COMPARISON_PRED(s64);
DEFINE_COMPARISON_PRED(u64);
DEFINE_COMPARISON_PRED(s32);
DEFINE_COMPARISON_PRED(u32);
DEFINE_COMPARISON_PRED(s16);
DEFINE_COMPARISON_PRED(u16);
DEFINE_COMPARISON_PRED(s8);
DEFINE_COMPARISON_PRED(u8);
DEFINE_EQUALITY_PRED(64);
DEFINE_EQUALITY_PRED(32);
DEFINE_EQUALITY_PRED(16);
DEFINE_EQUALITY_PRED(8);
static int filter_pred_and(struct filter_pred *pred __attribute((unused)),
void *event __attribute((unused)),
int val1, int val2)
{
return val1 && val2;
}
static int filter_pred_or(struct filter_pred *pred __attribute((unused)),
void *event __attribute((unused)),
int val1, int val2)
{
return val1 || val2;
}
/* Filter predicate for fixed sized arrays of characters */
static int filter_pred_string(struct filter_pred *pred, void *event,
int val1, int val2)
{
char *addr = (char *)(event + pred->offset);
int cmp, match;
cmp = pred->regex.match(addr, &pred->regex, pred->regex.field_len);
match = cmp ^ pred->not;
return match;
}
/* Filter predicate for char * pointers */
static int filter_pred_pchar(struct filter_pred *pred, void *event,
int val1, int val2)
{
char **addr = (char **)(event + pred->offset);
int cmp, match;
int len = strlen(*addr) + 1; /* including tailing '\0' */
cmp = pred->regex.match(*addr, &pred->regex, len);
match = cmp ^ pred->not;
return match;
}
/*
* Filter predicate for dynamic sized arrays of characters.
* These are implemented through a list of strings at the end
* of the entry.
* Also each of these strings have a field in the entry which
* contains its offset from the beginning of the entry.
* We have then first to get this field, dereference it
* and add it to the address of the entry, and at last we have
* the address of the string.
*/
static int filter_pred_strloc(struct filter_pred *pred, void *event,
int val1, int val2)
{
u32 str_item = *(u32 *)(event + pred->offset);
int str_loc = str_item & 0xffff;
int str_len = str_item >> 16;
char *addr = (char *)(event + str_loc);
int cmp, match;
cmp = pred->regex.match(addr, &pred->regex, str_len);
match = cmp ^ pred->not;
return match;
}
static int filter_pred_none(struct filter_pred *pred, void *event,
int val1, int val2)
{
return 0;
}
/*
* regex_match_foo - Basic regex callbacks
*
* @str: the string to be searched
* @r: the regex structure containing the pattern string
* @len: the length of the string to be searched (including '\0')
*
* Note:
* - @str might not be NULL-terminated if it's of type DYN_STRING
* or STATIC_STRING
*/
static int regex_match_full(char *str, struct regex *r, int len)
{
if (strncmp(str, r->pattern, len) == 0)
return 1;
return 0;
}
static int regex_match_front(char *str, struct regex *r, int len)
{
if (strncmp(str, r->pattern, r->len) == 0)
return 1;
return 0;
}
static int regex_match_middle(char *str, struct regex *r, int len)
{
if (strnstr(str, r->pattern, len))
return 1;
return 0;
}
static int regex_match_end(char *str, struct regex *r, int len)
{
int strlen = len - 1;
if (strlen >= r->len &&
memcmp(str + strlen - r->len, r->pattern, r->len) == 0)
return 1;
return 0;
}
/**
* filter_parse_regex - parse a basic regex
* @buff: the raw regex
* @len: length of the regex
* @search: will point to the beginning of the string to compare
* @not: tell whether the match will have to be inverted
*
* This passes in a buffer containing a regex and this function will
* set search to point to the search part of the buffer and
* return the type of search it is (see enum above).
* This does modify buff.
*
* Returns enum type.
* search returns the pointer to use for comparison.
* not returns 1 if buff started with a '!'
* 0 otherwise.
*/
enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
{
int type = MATCH_FULL;
int i;
if (buff[0] == '!') {
*not = 1;
buff++;
len--;
} else
*not = 0;
*search = buff;
for (i = 0; i < len; i++) {
if (buff[i] == '*') {
if (!i) {
*search = buff + 1;
type = MATCH_END_ONLY;
} else {
if (type == MATCH_END_ONLY)
type = MATCH_MIDDLE_ONLY;
else
type = MATCH_FRONT_ONLY;
buff[i] = 0;
break;
}
}
}
return type;
}
static void filter_build_regex(struct filter_pred *pred)
{
struct regex *r = &pred->regex;
char *search;
enum regex_type type = MATCH_FULL;
int not = 0;
if (pred->op == OP_GLOB) {
type = filter_parse_regex(r->pattern, r->len, &search, ¬);
r->len = strlen(search);
memmove(r->pattern, search, r->len+1);
}
switch (type) {
case MATCH_FULL:
r->match = regex_match_full;
break;
case MATCH_FRONT_ONLY:
r->match = regex_match_front;
break;
case MATCH_MIDDLE_ONLY:
r->match = regex_match_middle;
break;
case MATCH_END_ONLY:
r->match = regex_match_end;
break;
}
pred->not ^= not;
}
/* return 1 if event matches, 0 otherwise (discard) */
int filter_match_preds(struct event_filter *filter, void *rec)
{
int match, top = 0, val1 = 0, val2 = 0;
int stack[MAX_FILTER_PRED];
struct filter_pred *pred;
int i;
for (i = 0; i < filter->n_preds; i++) {
pred = filter->preds[i];
if (!pred->pop_n) {
match = pred->fn(pred, rec, val1, val2);
stack[top++] = match;
continue;
}
if (pred->pop_n > top) {
WARN_ON_ONCE(1);
return 0;
}
val1 = stack[--top];
val2 = stack[--top];
match = pred->fn(pred, rec, val1, val2);
stack[top++] = match;
}
return stack[--top];
}
EXPORT_SYMBOL_GPL(filter_match_preds);
static void parse_error(struct filter_parse_state *ps, int err, int pos)
{
ps->lasterr = err;
ps->lasterr_pos = pos;
}
static void remove_filter_string(struct event_filter *filter)
{
kfree(filter->filter_string);
filter->filter_string = NULL;
}
static int replace_filter_string(struct event_filter *filter,
char *filter_string)
{
kfree(filter->filter_string);
filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
if (!filter->filter_string)
return -ENOMEM;
return 0;
}
static int append_filter_string(struct event_filter *filter,
char *string)
{
int newlen;
char *new_filter_string;
BUG_ON(!filter->filter_string);
newlen = strlen(filter->filter_string) + strlen(string) + 1;
new_filter_string = kmalloc(newlen, GFP_KERNEL);
if (!new_filter_string)
return -ENOMEM;
strcpy(new_filter_string, filter->filter_string);
strcat(new_filter_string, string);
kfree(filter->filter_string);
filter->filter_string = new_filter_string;
return 0;
}
static void append_filter_err(struct filter_parse_state *ps,
struct event_filter *filter)
{
int pos = ps->lasterr_pos;
char *buf, *pbuf;
buf = (char *)__get_free_page(GFP_TEMPORARY);
if (!buf)
return;
append_filter_string(filter, "\n");
memset(buf, ' ', PAGE_SIZE);
if (pos > PAGE_SIZE - 128)
pos = 0;
buf[pos] = '^';
pbuf = &buf[pos] + 1;
sprintf(pbuf, "\nparse_error: %s\n", err_text[ps->lasterr]);
append_filter_string(filter, buf);
free_page((unsigned long) buf);
}
void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s)
{
struct event_filter *filter = call->filter;
mutex_lock(&event_mutex);
if (filter && filter->filter_string)
trace_seq_printf(s, "%s\n", filter->filter_string);
else
trace_seq_printf(s, "none\n");
mutex_unlock(&event_mutex);
}
void print_subsystem_event_filter(struct event_subsystem *system,
struct trace_seq *s)
{
struct event_filter *filter = system->filter;
mutex_lock(&event_mutex);
if (filter && filter->filter_string)
trace_seq_printf(s, "%s\n", filter->filter_string);
else
trace_seq_printf(s, "none\n");
mutex_unlock(&event_mutex);
}
static struct ftrace_event_field *
find_event_field(struct ftrace_event_call *call, char *name)
{
struct ftrace_event_field *field;
list_for_each_entry(field, &call->fields, link) {
if (!strcmp(field->name, name))
return field;
}
return NULL;
}
static void filter_free_pred(struct filter_pred *pred)
{
if (!pred)
return;
kfree(pred->field_name);
kfree(pred);
}
static void filter_clear_pred(struct filter_pred *pred)
{
kfree(pred->field_name);
pred->field_name = NULL;
pred->regex.len = 0;
}
static int filter_set_pred(struct filter_pred *dest,
struct filter_pred *src,
filter_pred_fn_t fn)
{
*dest = *src;
if (src->field_name) {
dest->field_name = kstrdup(src->field_name, GFP_KERNEL);
if (!dest->field_name)
return -ENOMEM;
}
dest->fn = fn;
return 0;
}
static void filter_disable_preds(struct ftrace_event_call *call)
{
struct event_filter *filter = call->filter;
int i;
call->filter_active = 0;
filter->n_preds = 0;
for (i = 0; i < MAX_FILTER_PRED; i++)
filter->preds[i]->fn = filter_pred_none;
}
static void __free_preds(struct event_filter *filter)
{
int i;
if (!filter)
return;
for (i = 0; i < MAX_FILTER_PRED; i++) {
if (filter->preds[i])
filter_free_pred(filter->preds[i]);
}
kfree(filter->preds);
kfree(filter->filter_string);
kfree(filter);
}
void destroy_preds(struct ftrace_event_call *call)
{
__free_preds(call->filter);
call->filter = NULL;
call->filter_active = 0;
}
static struct event_filter *__alloc_preds(void)
{
struct event_filter *filter;
struct filter_pred *pred;
int i;
filter = kzalloc(sizeof(*filter), GFP_KERNEL);
if (!filter)
return ERR_PTR(-ENOMEM);
filter->n_preds = 0;
filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
if (!filter->preds)
goto oom;
for (i = 0; i < MAX_FILTER_PRED; i++) {
pred = kzalloc(sizeof(*pred), GFP_KERNEL);
if (!pred)
goto oom;
pred->fn = filter_pred_none;
filter->preds[i] = pred;
}
return filter;
oom:
__free_preds(filter);
return ERR_PTR(-ENOMEM);
}
static int init_preds(struct ftrace_event_call *call)
{
if (call->filter)
return 0;
call->filter_active = 0;
call->filter = __alloc_preds();
if (IS_ERR(call->filter))
return PTR_ERR(call->filter);
return 0;
}
static int init_subsystem_preds(struct event_subsystem *system)
{
struct ftrace_event_call *call;
int err;
list_for_each_entry(call, &ftrace_events, list) {
if (!call->define_fields)
continue;
if (strcmp(call->system, system->name) != 0)
continue;
err = init_preds(call);
if (err)
return err;
}
return 0;
}
static void filter_free_subsystem_preds(struct event_subsystem *system)
{
struct ftrace_event_call *call;
list_for_each_entry(call, &ftrace_events, list) {
if (!call->define_fields)
continue;
if (strcmp(call->system, system->name) != 0)
continue;
filter_disable_preds(call);
remove_filter_string(call->filter);
}
}
static int filter_add_pred_fn(struct filter_parse_state *ps,
struct ftrace_event_call *call,
struct event_filter *filter,
struct filter_pred *pred,
filter_pred_fn_t fn)
{
int idx, err;
if (filter->n_preds == MAX_FILTER_PRED) {
parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
return -ENOSPC;
}
idx = filter->n_preds;
filter_clear_pred(filter->preds[idx]);
err = filter_set_pred(filter->preds[idx], pred, fn);
if (err)
return err;
filter->n_preds++;
return 0;
}
int filter_assign_type(const char *type)
{
if (strstr(type, "__data_loc") && strstr(type, "char"))
return FILTER_DYN_STRING;
if (strchr(type, '[') && strstr(type, "char"))
return FILTER_STATIC_STRING;
return FILTER_OTHER;
}
static bool is_string_field(struct ftrace_event_field *field)
{
return field->filter_type == FILTER_DYN_STRING ||
field->filter_type == FILTER_STATIC_STRING ||
field->filter_type == FILTER_PTR_STRING;
}
static int is_legal_op(struct ftrace_event_field *field, int op)
{
if (is_string_field(field) &&
(op != OP_EQ && op != OP_NE && op != OP_GLOB))
return 0;
if (!is_string_field(field) && op == OP_GLOB)
return 0;
return 1;
}
static filter_pred_fn_t select_comparison_fn(int op, int field_size,
int field_is_signed)
{
filter_pred_fn_t fn = NULL;
switch (field_size) {
case 8:
if (op == OP_EQ || op == OP_NE)
fn = filter_pred_64;
else if (field_is_signed)
fn = filter_pred_s64;
else
fn = filter_pred_u64;
break;
case 4:
if (op == OP_EQ || op == OP_NE)
fn = filter_pred_32;
else if (field_is_signed)
fn = filter_pred_s32;
else
fn = filter_pred_u32;
break;
case 2:
if (op == OP_EQ || op == OP_NE)
fn = filter_pred_16;
else if (field_is_signed)
fn = filter_pred_s16;
else
fn = filter_pred_u16;
break;
case 1:
if (op == OP_EQ || op == OP_NE)
fn = filter_pred_8;
else if (field_is_signed)
fn = filter_pred_s8;
else
fn = filter_pred_u8;
break;
}
return fn;
}
static int filter_add_pred(struct filter_parse_state *ps,
struct ftrace_event_call *call,
struct event_filter *filter,
struct filter_pred *pred,
bool dry_run)
{
struct ftrace_event_field *field;
filter_pred_fn_t fn;
unsigned long long val;
int ret;
pred->fn = filter_pred_none;
if (pred->op == OP_AND) {
pred->pop_n = 2;
fn = filter_pred_and;
goto add_pred_fn;
} else if (pred->op == OP_OR) {
pred->pop_n = 2;
fn = filter_pred_or;
goto add_pred_fn;
}
field = find_event_field(call, pred->field_name);
if (!field) {
parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
return -EINVAL;
}
pred->offset = field->offset;
if (!is_legal_op(field, pred->op)) {
parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
return -EINVAL;
}
if (is_string_field(field)) {
filter_build_regex(pred);
if (field->filter_type == FILTER_STATIC_STRING) {
fn = filter_pred_string;
pred->regex.field_len = field->size;
} else if (field->filter_type == FILTER_DYN_STRING)
fn = filter_pred_strloc;
else
fn = filter_pred_pchar;
} else {
if (field->is_signed)
ret = strict_strtoll(pred->regex.pattern, 0, &val);
else
ret = strict_strtoull(pred->regex.pattern, 0, &val);
if (ret) {
parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
return -EINVAL;
}
pred->val = val;
fn = select_comparison_fn(pred->op, field->size,
field->is_signed);
if (!fn) {
parse_error(ps, FILT_ERR_INVALID_OP, 0);
return -EINVAL;
}
}
if (pred->op == OP_NE)
pred->not = 1;
add_pred_fn:
if (!dry_run)
return filter_add_pred_fn(ps, call, filter, pred, fn);
return 0;
}
static void parse_init(struct filter_parse_state *ps,
struct filter_op *ops,
char *infix_string)
{
memset(ps, '\0', sizeof(*ps));
ps->infix.string = infix_string;
ps->infix.cnt = strlen(infix_string);
ps->ops = ops;
INIT_LIST_HEAD(&ps->opstack);
INIT_LIST_HEAD(&ps->postfix);
}
static char infix_next(struct filter_parse_state *ps)
{
ps->infix.cnt--;
return ps->infix.string[ps->infix.tail++];
}
static char infix_peek(struct filter_parse_state *ps)
{
if (ps->infix.tail == strlen(ps->infix.string))
return 0;
return ps->infix.string[ps->infix.tail];
}
static void infix_advance(struct filter_parse_state *ps)
{
ps->infix.cnt--;
ps->infix.tail++;
}
static inline int is_precedence_lower(struct filter_parse_state *ps,
int a, int b)
{
return ps->ops[a].precedence < ps->ops[b].precedence;
}
static inline int is_op_char(struct filter_parse_state *ps, char c)
{
int i;
for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
if (ps->ops[i].string[0] == c)
return 1;
}
return 0;
}
static int infix_get_op(struct filter_parse_state *ps, char firstc)
{
char nextc = infix_peek(ps);
char opstr[3];
int i;
opstr[0] = firstc;
opstr[1] = nextc;
opstr[2] = '\0';
for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
if (!strcmp(opstr, ps->ops[i].string)) {
infix_advance(ps);
return ps->ops[i].id;
}
}
opstr[1] = '\0';
for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
if (!strcmp(opstr, ps->ops[i].string))
return ps->ops[i].id;
}
return OP_NONE;
}
static inline void clear_operand_string(struct filter_parse_state *ps)
{
memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL);
ps->operand.tail = 0;
}
static inline int append_operand_char(struct filter_parse_state *ps, char c)
{
if (ps->operand.tail == MAX_FILTER_STR_VAL - 1)
return -EINVAL;
ps->operand.string[ps->operand.tail++] = c;
return 0;
}
static int filter_opstack_push(struct filter_parse_state *ps, int op)
{
struct opstack_op *opstack_op;
opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL);
if (!opstack_op)
return -ENOMEM;
opstack_op->op = op;
list_add(&opstack_op->list, &ps->opstack);
return 0;
}
static int filter_opstack_empty(struct filter_parse_state *ps)
{
return list_empty(&ps->opstack);
}
static int filter_opstack_top(struct filter_parse_state *ps)
{
struct opstack_op *opstack_op;
if (filter_opstack_empty(ps))
return OP_NONE;
opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
return opstack_op->op;
}
static int filter_opstack_pop(struct filter_parse_state *ps)
{
struct opstack_op *opstack_op;
int op;
if (filter_opstack_empty(ps))
return OP_NONE;
opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
op = opstack_op->op;
list_del(&opstack_op->list);
kfree(opstack_op);
return op;
}
static void filter_opstack_clear(struct filter_parse_state *ps)
{
while (!filter_opstack_empty(ps))
filter_opstack_pop(ps);
}
static char *curr_operand(struct filter_parse_state *ps)
{
return ps->operand.string;
}
static int postfix_append_operand(struct filter_parse_state *ps, char *operand)
{
struct postfix_elt *elt;
elt = kmalloc(sizeof(*elt), GFP_KERNEL);
if (!elt)
return -ENOMEM;
elt->op = OP_NONE;
elt->operand = kstrdup(operand, GFP_KERNEL);
if (!elt->operand) {
kfree(elt);
return -ENOMEM;
}
list_add_tail(&elt->list, &ps->postfix);
return 0;
}
static int postfix_append_op(struct filter_parse_state *ps, int op)
{
struct postfix_elt *elt;
elt = kmalloc(sizeof(*elt), GFP_KERNEL);
if (!elt)
return -ENOMEM;
elt->op = op;
elt->operand = NULL;
list_add_tail(&elt->list, &ps->postfix);
return 0;
}
static void postfix_clear(struct filter_parse_state *ps)
{
struct postfix_elt *elt;
while (!list_empty(&ps->postfix)) {
elt = list_first_entry(&ps->postfix, struct postfix_elt, list);
list_del(&elt->list);
kfree(elt->operand);
kfree(elt);
}
}
static int filter_parse(struct filter_parse_state *ps)
{
int in_string = 0;
int op, top_op;
char ch;
while ((ch = infix_next(ps))) {
if (ch == '"') {
in_string ^= 1;
continue;
}
if (in_string)
goto parse_operand;
if (isspace(ch))
continue;
if (is_op_char(ps, ch)) {
op = infix_get_op(ps, ch);
if (op == OP_NONE) {
parse_error(ps, FILT_ERR_INVALID_OP, 0);
return -EINVAL;
}
if (strlen(curr_operand(ps))) {
postfix_append_operand(ps, curr_operand(ps));
clear_operand_string(ps);
}
while (!filter_opstack_empty(ps)) {
top_op = filter_opstack_top(ps);
if (!is_precedence_lower(ps, top_op, op)) {
top_op = filter_opstack_pop(ps);
postfix_append_op(ps, top_op);
continue;
}
break;
}
filter_opstack_push(ps, op);
continue;
}
if (ch == '(') {
filter_opstack_push(ps, OP_OPEN_PAREN);
continue;
}
if (ch == ')') {
if (strlen(curr_operand(ps))) {
postfix_append_operand(ps, curr_operand(ps));
clear_operand_string(ps);
}
top_op = filter_opstack_pop(ps);
while (top_op != OP_NONE) {
if (top_op == OP_OPEN_PAREN)
break;
postfix_append_op(ps, top_op);
top_op = filter_opstack_pop(ps);
}
if (top_op == OP_NONE) {
parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
return -EINVAL;
}
continue;
}
parse_operand:
if (append_operand_char(ps, ch)) {
parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
return -EINVAL;
}
}
if (strlen(curr_operand(ps)))
postfix_append_operand(ps, curr_operand(ps));
while (!filter_opstack_empty(ps)) {
top_op = filter_opstack_pop(ps);
if (top_op == OP_NONE)
break;
if (top_op == OP_OPEN_PAREN) {
parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
return -EINVAL;
}
postfix_append_op(ps, top_op);
}
return 0;
}
static struct filter_pred *create_pred(int op, char *operand1, char *operand2)
{
struct filter_pred *pred;
pred = kzalloc(sizeof(*pred), GFP_KERNEL);
if (!pred)
return NULL;
pred->field_name = kstrdup(operand1, GFP_KERNEL);
if (!pred->field_name) {
kfree(pred);
return NULL;
}
strcpy(pred->regex.pattern, operand2);
pred->regex.len = strlen(pred->regex.pattern);
pred->op = op;
return pred;
}
static struct filter_pred *create_logical_pred(int op)
{
struct filter_pred *pred;
pred = kzalloc(sizeof(*pred), GFP_KERNEL);
if (!pred)
return NULL;
pred->op = op;
return pred;
}
static int check_preds(struct filter_parse_state *ps)
{
int n_normal_preds = 0, n_logical_preds = 0;
struct postfix_elt *elt;
list_for_each_entry(elt, &ps->postfix, list) {
if (elt->op == OP_NONE)
continue;
if (elt->op == OP_AND || elt->op == OP_OR) {
n_logical_preds++;
continue;
}
n_normal_preds++;
}
if (!n_normal_preds || n_logical_preds >= n_normal_preds) {
parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
return -EINVAL;
}
return 0;
}
static int replace_preds(struct ftrace_event_call *call,
struct event_filter *filter,
struct filter_parse_state *ps,
char *filter_string,
bool dry_run)
{
char *operand1 = NULL, *operand2 = NULL;
struct filter_pred *pred;
struct postfix_elt *elt;
int err;
int n_preds = 0;
err = check_preds(ps);
if (err)
return err;
list_for_each_entry(elt, &ps->postfix, list) {
if (elt->op == OP_NONE) {
if (!operand1)
operand1 = elt->operand;
else if (!operand2)
operand2 = elt->operand;
else {
parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
return -EINVAL;
}
continue;
}
if (n_preds++ == MAX_FILTER_PRED) {
parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
return -ENOSPC;
}
if (elt->op == OP_AND || elt->op == OP_OR) {
pred = create_logical_pred(elt->op);
goto add_pred;
}
if (!operand1 || !operand2) {
parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
return -EINVAL;
}
pred = create_pred(elt->op, operand1, operand2);
add_pred:
if (!pred)
return -ENOMEM;
err = filter_add_pred(ps, call, filter, pred, dry_run);
filter_free_pred(pred);
if (err)
return err;
operand1 = operand2 = NULL;
}
return 0;
}
static int replace_system_preds(struct event_subsystem *system,
struct filter_parse_state *ps,
char *filter_string)
{
struct ftrace_event_call *call;
bool fail = true;
int err;
list_for_each_entry(call, &ftrace_events, list) {
struct event_filter *filter = call->filter;
if (!call->define_fields)
continue;
if (strcmp(call->system, system->name) != 0)
continue;
/* try to see if the filter can be applied */
err = replace_preds(call, filter, ps, filter_string, true);
if (err)
continue;
/* really apply the filter */
filter_disable_preds(call);
err = replace_preds(call, filter, ps, filter_string, false);
if (err)
filter_disable_preds(call);
else {
call->filter_active = 1;
replace_filter_string(filter, filter_string);
}
fail = false;
}
if (fail) {
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
return -EINVAL;
}
return 0;
}
int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
{
int err;
struct filter_parse_state *ps;
mutex_lock(&event_mutex);
err = init_preds(call);
if (err)
goto out_unlock;
if (!strcmp(strstrip(filter_string), "0")) {
filter_disable_preds(call);
remove_filter_string(call->filter);
goto out_unlock;
}
err = -ENOMEM;
ps = kzalloc(sizeof(*ps), GFP_KERNEL);
if (!ps)
goto out_unlock;
filter_disable_preds(call);
replace_filter_string(call->filter, filter_string);
parse_init(ps, filter_ops, filter_string);
err = filter_parse(ps);
if (err) {
append_filter_err(ps, call->filter);
goto out;
}
err = replace_preds(call, call->filter, ps, filter_string, false);
if (err)
append_filter_err(ps, call->filter);
else
call->filter_active = 1;
out:
filter_opstack_clear(ps);
postfix_clear(ps);
kfree(ps);
out_unlock:
mutex_unlock(&event_mutex);
return err;
}
int apply_subsystem_event_filter(struct event_subsystem *system,
char *filter_string)
{
int err;
struct filter_parse_state *ps;
mutex_lock(&event_mutex);
err = init_subsystem_preds(system);
if (err)
goto out_unlock;
if (!strcmp(strstrip(filter_string), "0")) {
filter_free_subsystem_preds(system);
remove_filter_string(system->filter);
goto out_unlock;
}
err = -ENOMEM;
ps = kzalloc(sizeof(*ps), GFP_KERNEL);
if (!ps)
goto out_unlock;
replace_filter_string(system->filter, filter_string);
parse_init(ps, filter_ops, filter_string);
err = filter_parse(ps);
if (err) {
append_filter_err(ps, system->filter);
goto out;
}
err = replace_system_preds(system, ps, filter_string);
if (err)
append_filter_err(ps, system->filter);
out:
filter_opstack_clear(ps);
postfix_clear(ps);
kfree(ps);
out_unlock:
mutex_unlock(&event_mutex);
return err;
}
#ifdef CONFIG_EVENT_PROFILE
void ftrace_profile_free_filter(struct perf_event *event)
{
struct event_filter *filter = event->filter;
event->filter = NULL;
__free_preds(filter);
}
int ftrace_profile_set_filter(struct perf_event *event, int event_id,
char *filter_str)
{
int err;
struct event_filter *filter;
struct filter_parse_state *ps;
struct ftrace_event_call *call = NULL;
mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
if (call->id == event_id)
break;
}
err = -EINVAL;
if (!call)
goto out_unlock;
err = -EEXIST;
if (event->filter)
goto out_unlock;
filter = __alloc_preds();
if (IS_ERR(filter)) {
err = PTR_ERR(filter);
goto out_unlock;
}
err = -ENOMEM;
ps = kzalloc(sizeof(*ps), GFP_KERNEL);
if (!ps)
goto free_preds;
parse_init(ps, filter_ops, filter_str);
err = filter_parse(ps);
if (err)
goto free_ps;
err = replace_preds(call, filter, ps, filter_str, false);
if (!err)
event->filter = filter;
free_ps:
filter_opstack_clear(ps);
postfix_clear(ps);
kfree(ps);
free_preds:
if (err)
__free_preds(filter);
out_unlock:
mutex_unlock(&event_mutex);
return err;
}
#endif /* CONFIG_EVENT_PROFILE */