--- /dev/null
+/*
+ * 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 <linux/slab.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+#define DEFAULT_SYS_FILTER_MESSAGE \
+ "### global filter ###\n" \
+ "# Use this to set filters for multiple events.\n" \
+ "# Only events with the given fields will be affected.\n" \
+ "# If no events are modified, an error message will be displayed here"
+
+enum filter_op_ids
+{
+ OP_OR,
+ OP_AND,
+ OP_GLOB,
+ OP_NE,
+ OP_EQ,
+ OP_LT,
+ OP_LE,
+ OP_GT,
+ OP_GE,
+ OP_BAND,
+ OP_NOT,
+ OP_NONE,
+ OP_OPEN_PAREN,
+};
+
+struct filter_op {
+ int id;
+ char *string;
+ int precedence;
+};
+
+/* Order must be the same as enum filter_op_ids above */
+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_BAND, "&", 6 },
+ { OP_NOT, "!", 6 },
+ { 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,
+ FILT_ERR_IP_FIELD_ONLY,
+ FILT_ERR_ILLEGAL_NOT_OP,
+};
+
+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",
+ "Only 'ip' field is supported for function trace",
+ "Illegal use of '!'",
+};
+
+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;
+};
+
+struct pred_stack {
+ struct filter_pred **preds;
+ int index;
+};
+
+/* If not of not match is equal to not of not, then it is a match */
+#define DEFINE_COMPARISON_PRED(type) \
+static int filter_pred_##type(struct filter_pred *pred, void *event) \
+{ \
+ 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; \
+ case OP_BAND: \
+ match = (*addr & val); \
+ break; \
+ default: \
+ break; \
+ } \
+ \
+ return !!match == !pred->not; \
+}
+
+#define DEFINE_EQUALITY_PRED(size) \
+static int filter_pred_##size(struct filter_pred *pred, void *event) \
+{ \
+ 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);
+
+/* Filter predicate for fixed sized arrays of characters */
+static int filter_pred_string(struct filter_pred *pred, void *event)
+{
+ 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)
+{
+ 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)
+{
+ 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)
+{
+ 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;
+}
+
+enum move_type {
+ MOVE_DOWN,
+ MOVE_UP_FROM_LEFT,
+ MOVE_UP_FROM_RIGHT
+};
+
+static struct filter_pred *
+get_pred_parent(struct filter_pred *pred, struct filter_pred *preds,
+ int index, enum move_type *move)
+{
+ if (pred->parent & FILTER_PRED_IS_RIGHT)
+ *move = MOVE_UP_FROM_RIGHT;
+ else
+ *move = MOVE_UP_FROM_LEFT;
+ pred = &preds[pred->parent & ~FILTER_PRED_IS_RIGHT];
+
+ return pred;
+}
+
+enum walk_return {
+ WALK_PRED_ABORT,
+ WALK_PRED_PARENT,
+ WALK_PRED_DEFAULT,
+};
+
+typedef int (*filter_pred_walkcb_t) (enum move_type move,
+ struct filter_pred *pred,
+ int *err, void *data);
+
+static int walk_pred_tree(struct filter_pred *preds,
+ struct filter_pred *root,
+ filter_pred_walkcb_t cb, void *data)
+{
+ struct filter_pred *pred = root;
+ enum move_type move = MOVE_DOWN;
+ int done = 0;
+
+ if (!preds)
+ return -EINVAL;
+
+ do {
+ int err = 0, ret;
+
+ ret = cb(move, pred, &err, data);
+ if (ret == WALK_PRED_ABORT)
+ return err;
+ if (ret == WALK_PRED_PARENT)
+ goto get_parent;
+
+ switch (move) {
+ case MOVE_DOWN:
+ if (pred->left != FILTER_PRED_INVALID) {
+ pred = &preds[pred->left];
+ continue;
+ }
+ goto get_parent;
+ case MOVE_UP_FROM_LEFT:
+ pred = &preds[pred->right];
+ move = MOVE_DOWN;
+ continue;
+ case MOVE_UP_FROM_RIGHT:
+ get_parent:
+ if (pred == root)
+ break;
+ pred = get_pred_parent(pred, preds,
+ pred->parent,
+ &move);
+ continue;
+ }
+ done = 1;
+ } while (!done);
+
+ /* We are fine. */
+ return 0;
+}
+
+/*
+ * A series of AND or ORs where found together. Instead of
+ * climbing up and down the tree branches, an array of the
+ * ops were made in order of checks. We can just move across
+ * the array and short circuit if needed.
+ */
+static int process_ops(struct filter_pred *preds,
+ struct filter_pred *op, void *rec)
+{
+ struct filter_pred *pred;
+ int match = 0;
+ int type;
+ int i;
+
+ /*
+ * Micro-optimization: We set type to true if op
+ * is an OR and false otherwise (AND). Then we
+ * just need to test if the match is equal to
+ * the type, and if it is, we can short circuit the
+ * rest of the checks:
+ *
+ * if ((match && op->op == OP_OR) ||
+ * (!match && op->op == OP_AND))
+ * return match;
+ */
+ type = op->op == OP_OR;
+
+ for (i = 0; i < op->val; i++) {
+ pred = &preds[op->ops[i]];
+ if (!WARN_ON_ONCE(!pred->fn))
+ match = pred->fn(pred, rec);
+ if (!!match == type)
+ break;
+ }
+ /* If not of not match is equal to not of not, then it is a match */
+ return !!match == !op->not;
+}
+
+struct filter_match_preds_data {
+ struct filter_pred *preds;
+ int match;
+ void *rec;
+};
+
+static int filter_match_preds_cb(enum move_type move, struct filter_pred *pred,
+ int *err, void *data)
+{
+ struct filter_match_preds_data *d = data;
+
+ *err = 0;
+ switch (move) {
+ case MOVE_DOWN:
+ /* only AND and OR have children */
+ if (pred->left != FILTER_PRED_INVALID) {
+ /* If ops is set, then it was folded. */
+ if (!pred->ops)
+ return WALK_PRED_DEFAULT;
+ /* We can treat folded ops as a leaf node */
+ d->match = process_ops(d->preds, pred, d->rec);
+ } else {
+ if (!WARN_ON_ONCE(!pred->fn))
+ d->match = pred->fn(pred, d->rec);
+ }
+
+ return WALK_PRED_PARENT;
+ case MOVE_UP_FROM_LEFT:
+ /*
+ * Check for short circuits.
+ *
+ * Optimization: !!match == (pred->op == OP_OR)
+ * is the same as:
+ * if ((match && pred->op == OP_OR) ||
+ * (!match && pred->op == OP_AND))
+ */
+ if (!!d->match == (pred->op == OP_OR))
+ return WALK_PRED_PARENT;
+ break;
+ case MOVE_UP_FROM_RIGHT:
+ break;
+ }
+
+ return WALK_PRED_DEFAULT;
+}
+
+/* return 1 if event matches, 0 otherwise (discard) */
+int filter_match_preds(struct event_filter *filter, void *rec)
+{
+ struct filter_pred *preds;
+ struct filter_pred *root;
+ struct filter_match_preds_data data = {
+ /* match is currently meaningless */
+ .match = -1,
+ .rec = rec,
+ };
+ int n_preds, ret;
+
+ /* no filter is considered a match */
+ if (!filter)
+ return 1;
+
+ n_preds = filter->n_preds;
+ if (!n_preds)
+ return 1;
+
+ /*
+ * n_preds, root and filter->preds are protect with preemption disabled.
+ */
+ root = rcu_dereference_sched(filter->root);
+ if (!root)
+ return 1;
+
+ data.preds = preds = rcu_dereference_sched(filter->preds);
+ ret = walk_pred_tree(preds, root, filter_match_preds_cb, &data);
+ WARN_ON(ret);
+ return data.match;
+}
+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)
+{
+ if (!filter)
+ return;
+
+ 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);
+}
+
+static inline struct event_filter *event_filter(struct ftrace_event_file *file)
+{
+ if (file->event_call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ return file->event_call->filter;
+ else
+ return file->filter;
+}
+
+/* caller must hold event_mutex */
+void print_event_filter(struct ftrace_event_file *file, struct trace_seq *s)
+{
+ struct event_filter *filter = event_filter(file);
+
+ if (filter && filter->filter_string)
+ trace_seq_printf(s, "%s\n", filter->filter_string);
+ else
+ trace_seq_puts(s, "none\n");
+}
+
+void print_subsystem_event_filter(struct event_subsystem *system,
+ struct trace_seq *s)
+{
+ struct event_filter *filter;
+
+ mutex_lock(&event_mutex);
+ filter = system->filter;
+ if (filter && filter->filter_string)
+ trace_seq_printf(s, "%s\n", filter->filter_string);
+ else
+ trace_seq_puts(s, DEFAULT_SYS_FILTER_MESSAGE "\n");
+ mutex_unlock(&event_mutex);
+}
+
+static int __alloc_pred_stack(struct pred_stack *stack, int n_preds)
+{
+ stack->preds = kcalloc(n_preds + 1, sizeof(*stack->preds), GFP_KERNEL);
+ if (!stack->preds)
+ return -ENOMEM;
+ stack->index = n_preds;
+ return 0;
+}
+
+static void __free_pred_stack(struct pred_stack *stack)
+{
+ kfree(stack->preds);
+ stack->index = 0;
+}
+
+static int __push_pred_stack(struct pred_stack *stack,
+ struct filter_pred *pred)
+{
+ int index = stack->index;
+
+ if (WARN_ON(index == 0))
+ return -ENOSPC;
+
+ stack->preds[--index] = pred;
+ stack->index = index;
+ return 0;
+}
+
+static struct filter_pred *
+__pop_pred_stack(struct pred_stack *stack)
+{
+ struct filter_pred *pred;
+ int index = stack->index;
+
+ pred = stack->preds[index++];
+ if (!pred)
+ return NULL;
+
+ stack->index = index;
+ return pred;
+}
+
+static int filter_set_pred(struct event_filter *filter,
+ int idx,
+ struct pred_stack *stack,
+ struct filter_pred *src)
+{
+ struct filter_pred *dest = &filter->preds[idx];
+ struct filter_pred *left;
+ struct filter_pred *right;
+
+ *dest = *src;
+ dest->index = idx;
+
+ if (dest->op == OP_OR || dest->op == OP_AND) {
+ right = __pop_pred_stack(stack);
+ left = __pop_pred_stack(stack);
+ if (!left || !right)
+ return -EINVAL;
+ /*
+ * If both children can be folded
+ * and they are the same op as this op or a leaf,
+ * then this op can be folded.
+ */
+ if (left->index & FILTER_PRED_FOLD &&
+ ((left->op == dest->op && !left->not) ||
+ left->left == FILTER_PRED_INVALID) &&
+ right->index & FILTER_PRED_FOLD &&
+ ((right->op == dest->op && !right->not) ||
+ right->left == FILTER_PRED_INVALID))
+ dest->index |= FILTER_PRED_FOLD;
+
+ dest->left = left->index & ~FILTER_PRED_FOLD;
+ dest->right = right->index & ~FILTER_PRED_FOLD;
+ left->parent = dest->index & ~FILTER_PRED_FOLD;
+ right->parent = dest->index | FILTER_PRED_IS_RIGHT;
+ } else {
+ /*
+ * Make dest->left invalid to be used as a quick
+ * way to know this is a leaf node.
+ */
+ dest->left = FILTER_PRED_INVALID;
+
+ /* All leafs allow folding the parent ops. */
+ dest->index |= FILTER_PRED_FOLD;
+ }
+
+ return __push_pred_stack(stack, dest);
+}
+
+static void __free_preds(struct event_filter *filter)
+{
+ int i;
+
+ if (filter->preds) {
+ for (i = 0; i < filter->n_preds; i++)
+ kfree(filter->preds[i].ops);
+ kfree(filter->preds);
+ filter->preds = NULL;
+ }
+ filter->a_preds = 0;
+ filter->n_preds = 0;
+}
+
+static void filter_disable(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ call->flags &= ~TRACE_EVENT_FL_FILTERED;
+ else
+ file->flags &= ~FTRACE_EVENT_FL_FILTERED;
+}
+
+static void __free_filter(struct event_filter *filter)
+{
+ if (!filter)
+ return;
+
+ __free_preds(filter);
+ kfree(filter->filter_string);
+ kfree(filter);
+}
+
+void free_event_filter(struct event_filter *filter)
+{
+ __free_filter(filter);
+}
+
+static struct event_filter *__alloc_filter(void)
+{
+ struct event_filter *filter;
+
+ filter = kzalloc(sizeof(*filter), GFP_KERNEL);
+ return filter;
+}
+
+static int __alloc_preds(struct event_filter *filter, int n_preds)
+{
+ struct filter_pred *pred;
+ int i;
+
+ if (filter->preds)
+ __free_preds(filter);
+
+ filter->preds = kcalloc(n_preds, sizeof(*filter->preds), GFP_KERNEL);
+
+ if (!filter->preds)
+ return -ENOMEM;
+
+ filter->a_preds = n_preds;
+ filter->n_preds = 0;
+
+ for (i = 0; i < n_preds; i++) {
+ pred = &filter->preds[i];
+ pred->fn = filter_pred_none;
+ }
+
+ return 0;
+}
+
+static inline void __remove_filter(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ filter_disable(file);
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ remove_filter_string(call->filter);
+ else
+ remove_filter_string(file->filter);
+}
+
+static void filter_free_subsystem_preds(struct ftrace_subsystem_dir *dir,
+ struct trace_array *tr)
+{
+ struct ftrace_event_file *file;
+
+ list_for_each_entry(file, &tr->events, list) {
+ if (file->system != dir)
+ continue;
+ __remove_filter(file);
+ }
+}
+
+static inline void __free_subsystem_filter(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER) {
+ __free_filter(call->filter);
+ call->filter = NULL;
+ } else {
+ __free_filter(file->filter);
+ file->filter = NULL;
+ }
+}
+
+static void filter_free_subsystem_filters(struct ftrace_subsystem_dir *dir,
+ struct trace_array *tr)
+{
+ struct ftrace_event_file *file;
+
+ list_for_each_entry(file, &tr->events, list) {
+ if (file->system != dir)
+ continue;
+ __free_subsystem_filter(file);
+ }
+}
+
+static int filter_add_pred(struct filter_parse_state *ps,
+ struct event_filter *filter,
+ struct filter_pred *pred,
+ struct pred_stack *stack)
+{
+ int err;
+
+ if (WARN_ON(filter->n_preds == filter->a_preds)) {
+ parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
+ return -ENOSPC;
+ }
+
+ err = filter_set_pred(filter, filter->n_preds, stack, pred);
+ 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_function_field(struct ftrace_event_field *field)
+{
+ return field->filter_type == FILTER_TRACE_FN;
+}
+
+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 init_pred(struct filter_parse_state *ps,
+ struct ftrace_event_field *field,
+ struct filter_pred *pred)
+
+{
+ filter_pred_fn_t fn = filter_pred_none;
+ unsigned long long val;
+ int ret;
+
+ 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 (is_function_field(field)) {
+ if (strcmp(field->name, "ip")) {
+ parse_error(ps, FILT_ERR_IP_FIELD_ONLY, 0);
+ return -EINVAL;
+ }
+ } else {
+ if (field->is_signed)
+ ret = kstrtoll(pred->regex.pattern, 0, &val);
+ else
+ ret = kstrtoull(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;
+
+ pred->fn = 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(struct filter_parse_state *ps,
+ struct ftrace_event_call *call,
+ int op, char *operand1, char *operand2)
+{
+ struct ftrace_event_field *field;
+ static struct filter_pred pred;
+
+ memset(&pred, 0, sizeof(pred));
+ pred.op = op;
+
+ if (op == OP_AND || op == OP_OR)
+ return &pred;
+
+ if (!operand1 || !operand2) {
+ parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
+ return NULL;
+ }
+
+ field = trace_find_event_field(call, operand1);
+ if (!field) {
+ parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
+ return NULL;
+ }
+
+ strcpy(pred.regex.pattern, operand2);
+ pred.regex.len = strlen(pred.regex.pattern);
+ pred.field = field;
+ return init_pred(ps, field, &pred) ? NULL : &pred;
+}
+
+static int check_preds(struct filter_parse_state *ps)
+{
+ int n_normal_preds = 0, n_logical_preds = 0;
+ struct postfix_elt *elt;
+ int cnt = 0;
+
+ list_for_each_entry(elt, &ps->postfix, list) {
+ if (elt->op == OP_NONE) {
+ cnt++;
+ continue;
+ }
+
+ if (elt->op == OP_AND || elt->op == OP_OR) {
+ n_logical_preds++;
+ cnt--;
+ continue;
+ }
+ if (elt->op != OP_NOT)
+ cnt--;
+ n_normal_preds++;
+ WARN_ON_ONCE(cnt < 0);
+ }
+
+ if (cnt != 1 || !n_normal_preds || n_logical_preds >= n_normal_preds) {
+ parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int count_preds(struct filter_parse_state *ps)
+{
+ struct postfix_elt *elt;
+ int n_preds = 0;
+
+ list_for_each_entry(elt, &ps->postfix, list) {
+ if (elt->op == OP_NONE)
+ continue;
+ n_preds++;
+ }
+
+ return n_preds;
+}
+
+struct check_pred_data {
+ int count;
+ int max;
+};
+
+static int check_pred_tree_cb(enum move_type move, struct filter_pred *pred,
+ int *err, void *data)
+{
+ struct check_pred_data *d = data;
+
+ if (WARN_ON(d->count++ > d->max)) {
+ *err = -EINVAL;
+ return WALK_PRED_ABORT;
+ }
+ return WALK_PRED_DEFAULT;
+}
+
+/*
+ * The tree is walked at filtering of an event. If the tree is not correctly
+ * built, it may cause an infinite loop. Check here that the tree does
+ * indeed terminate.
+ */
+static int check_pred_tree(struct event_filter *filter,
+ struct filter_pred *root)
+{
+ struct check_pred_data data = {
+ /*
+ * The max that we can hit a node is three times.
+ * Once going down, once coming up from left, and
+ * once coming up from right. This is more than enough
+ * since leafs are only hit a single time.
+ */
+ .max = 3 * filter->n_preds,
+ .count = 0,
+ };
+
+ return walk_pred_tree(filter->preds, root,
+ check_pred_tree_cb, &data);
+}
+
+static int count_leafs_cb(enum move_type move, struct filter_pred *pred,
+ int *err, void *data)
+{
+ int *count = data;
+
+ if ((move == MOVE_DOWN) &&
+ (pred->left == FILTER_PRED_INVALID))
+ (*count)++;
+
+ return WALK_PRED_DEFAULT;
+}
+
+static int count_leafs(struct filter_pred *preds, struct filter_pred *root)
+{
+ int count = 0, ret;
+
+ ret = walk_pred_tree(preds, root, count_leafs_cb, &count);
+ WARN_ON(ret);
+ return count;
+}
+
+struct fold_pred_data {
+ struct filter_pred *root;
+ int count;
+ int children;
+};
+
+static int fold_pred_cb(enum move_type move, struct filter_pred *pred,
+ int *err, void *data)
+{
+ struct fold_pred_data *d = data;
+ struct filter_pred *root = d->root;
+
+ if (move != MOVE_DOWN)
+ return WALK_PRED_DEFAULT;
+ if (pred->left != FILTER_PRED_INVALID)
+ return WALK_PRED_DEFAULT;
+
+ if (WARN_ON(d->count == d->children)) {
+ *err = -EINVAL;
+ return WALK_PRED_ABORT;
+ }
+
+ pred->index &= ~FILTER_PRED_FOLD;
+ root->ops[d->count++] = pred->index;
+ return WALK_PRED_DEFAULT;
+}
+
+static int fold_pred(struct filter_pred *preds, struct filter_pred *root)
+{
+ struct fold_pred_data data = {
+ .root = root,
+ .count = 0,
+ };
+ int children;
+
+ /* No need to keep the fold flag */
+ root->index &= ~FILTER_PRED_FOLD;
+
+ /* If the root is a leaf then do nothing */
+ if (root->left == FILTER_PRED_INVALID)
+ return 0;
+
+ /* count the children */
+ children = count_leafs(preds, &preds[root->left]);
+ children += count_leafs(preds, &preds[root->right]);
+
+ root->ops = kcalloc(children, sizeof(*root->ops), GFP_KERNEL);
+ if (!root->ops)
+ return -ENOMEM;
+
+ root->val = children;
+ data.children = children;
+ return walk_pred_tree(preds, root, fold_pred_cb, &data);
+}
+
+static int fold_pred_tree_cb(enum move_type move, struct filter_pred *pred,
+ int *err, void *data)
+{
+ struct filter_pred *preds = data;
+
+ if (move != MOVE_DOWN)
+ return WALK_PRED_DEFAULT;
+ if (!(pred->index & FILTER_PRED_FOLD))
+ return WALK_PRED_DEFAULT;
+
+ *err = fold_pred(preds, pred);
+ if (*err)
+ return WALK_PRED_ABORT;
+
+ /* eveyrhing below is folded, continue with parent */
+ return WALK_PRED_PARENT;
+}
+
+/*
+ * To optimize the processing of the ops, if we have several "ors" or
+ * "ands" together, we can put them in an array and process them all
+ * together speeding up the filter logic.
+ */
+static int fold_pred_tree(struct event_filter *filter,
+ struct filter_pred *root)
+{
+ return walk_pred_tree(filter->preds, root, fold_pred_tree_cb,
+ filter->preds);
+}
+
+static int replace_preds(struct ftrace_event_call *call,
+ struct event_filter *filter,
+ struct filter_parse_state *ps,
+ bool dry_run)
+{
+ char *operand1 = NULL, *operand2 = NULL;
+ struct filter_pred *pred;
+ struct filter_pred *root;
+ struct postfix_elt *elt;
+ struct pred_stack stack = { }; /* init to NULL */
+ int err;
+ int n_preds = 0;
+
+ n_preds = count_preds(ps);
+ if (n_preds >= MAX_FILTER_PRED) {
+ parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
+ return -ENOSPC;
+ }
+
+ err = check_preds(ps);
+ if (err)
+ return err;
+
+ if (!dry_run) {
+ err = __alloc_pred_stack(&stack, n_preds);
+ if (err)
+ return err;
+ err = __alloc_preds(filter, n_preds);
+ if (err)
+ goto fail;
+ }
+
+ n_preds = 0;
+ 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);
+ err = -EINVAL;
+ goto fail;
+ }
+ continue;
+ }
+
+ if (elt->op == OP_NOT) {
+ if (!n_preds || operand1 || operand2) {
+ parse_error(ps, FILT_ERR_ILLEGAL_NOT_OP, 0);
+ err = -EINVAL;
+ goto fail;
+ }
+ if (!dry_run)
+ filter->preds[n_preds - 1].not ^= 1;
+ continue;
+ }
+
+ if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
+ parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
+ err = -ENOSPC;
+ goto fail;
+ }
+
+ pred = create_pred(ps, call, elt->op, operand1, operand2);
+ if (!pred) {
+ err = -EINVAL;
+ goto fail;
+ }
+
+ if (!dry_run) {
+ err = filter_add_pred(ps, filter, pred, &stack);
+ if (err)
+ goto fail;
+ }
+
+ operand1 = operand2 = NULL;
+ }
+
+ if (!dry_run) {
+ /* We should have one item left on the stack */
+ pred = __pop_pred_stack(&stack);
+ if (!pred)
+ return -EINVAL;
+ /* This item is where we start from in matching */
+ root = pred;
+ /* Make sure the stack is empty */
+ pred = __pop_pred_stack(&stack);
+ if (WARN_ON(pred)) {
+ err = -EINVAL;
+ filter->root = NULL;
+ goto fail;
+ }
+ err = check_pred_tree(filter, root);
+ if (err)
+ goto fail;
+
+ /* Optimize the tree */
+ err = fold_pred_tree(filter, root);
+ if (err)
+ goto fail;
+
+ /* We don't set root until we know it works */
+ barrier();
+ filter->root = root;
+ }
+
+ err = 0;
+fail:
+ __free_pred_stack(&stack);
+ return err;
+}
+
+static inline void event_set_filtered_flag(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ call->flags |= TRACE_EVENT_FL_FILTERED;
+ else
+ file->flags |= FTRACE_EVENT_FL_FILTERED;
+}
+
+static inline void event_set_filter(struct ftrace_event_file *file,
+ struct event_filter *filter)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ rcu_assign_pointer(call->filter, filter);
+ else
+ rcu_assign_pointer(file->filter, filter);
+}
+
+static inline void event_clear_filter(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ RCU_INIT_POINTER(call->filter, NULL);
+ else
+ RCU_INIT_POINTER(file->filter, NULL);
+}
+
+static inline void
+event_set_no_set_filter_flag(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ call->flags |= TRACE_EVENT_FL_NO_SET_FILTER;
+ else
+ file->flags |= FTRACE_EVENT_FL_NO_SET_FILTER;
+}
+
+static inline void
+event_clear_no_set_filter_flag(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (call->flags & TRACE_EVENT_FL_USE_CALL_FILTER)
+ call->flags &= ~TRACE_EVENT_FL_NO_SET_FILTER;
+ else
+ file->flags &= ~FTRACE_EVENT_FL_NO_SET_FILTER;
+}
+
+static inline bool
+event_no_set_filter_flag(struct ftrace_event_file *file)
+{
+ struct ftrace_event_call *call = file->event_call;
+
+ if (file->flags & FTRACE_EVENT_FL_NO_SET_FILTER)
+ return true;
+
+ if ((call->flags & TRACE_EVENT_FL_USE_CALL_FILTER) &&
+ (call->flags & TRACE_EVENT_FL_NO_SET_FILTER))
+ return true;
+
+ return false;
+}
+
+struct filter_list {
+ struct list_head list;
+ struct event_filter *filter;
+};
+
+static int replace_system_preds(struct ftrace_subsystem_dir *dir,
+ struct trace_array *tr,
+ struct filter_parse_state *ps,
+ char *filter_string)
+{
+ struct ftrace_event_file *file;
+ struct filter_list *filter_item;
+ struct filter_list *tmp;
+ LIST_HEAD(filter_list);
+ bool fail = true;
+ int err;
+
+ list_for_each_entry(file, &tr->events, list) {
+ if (file->system != dir)
+ continue;
+
+ /*
+ * Try to see if the filter can be applied
+ * (filter arg is ignored on dry_run)
+ */
+ err = replace_preds(file->event_call, NULL, ps, true);
+ if (err)
+ event_set_no_set_filter_flag(file);
+ else
+ event_clear_no_set_filter_flag(file);
+ }
+
+ list_for_each_entry(file, &tr->events, list) {
+ struct event_filter *filter;
+
+ if (file->system != dir)
+ continue;
+
+ if (event_no_set_filter_flag(file))
+ continue;
+
+ filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
+ if (!filter_item)
+ goto fail_mem;
+
+ list_add_tail(&filter_item->list, &filter_list);
+
+ filter_item->filter = __alloc_filter();
+ if (!filter_item->filter)
+ goto fail_mem;
+ filter = filter_item->filter;
+
+ /* Can only fail on no memory */
+ err = replace_filter_string(filter, filter_string);
+ if (err)
+ goto fail_mem;
+
+ err = replace_preds(file->event_call, filter, ps, false);
+ if (err) {
+ filter_disable(file);
+ parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
+ append_filter_err(ps, filter);
+ } else
+ event_set_filtered_flag(file);
+ /*
+ * Regardless of if this returned an error, we still
+ * replace the filter for the call.
+ */
+ filter = event_filter(file);
+ event_set_filter(file, filter_item->filter);
+ filter_item->filter = filter;
+
+ fail = false;
+ }
+
+ if (fail)
+ goto fail;
+
+ /*
+ * The calls can still be using the old filters.
+ * Do a synchronize_sched() to ensure all calls are
+ * done with them before we free them.
+ */
+ synchronize_sched();
+ list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
+ __free_filter(filter_item->filter);
+ list_del(&filter_item->list);
+ kfree(filter_item);
+ }
+ return 0;
+ fail:
+ /* No call succeeded */
+ list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
+ list_del(&filter_item->list);
+ kfree(filter_item);
+ }
+ parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
+ return -EINVAL;
+ fail_mem:
+ /* If any call succeeded, we still need to sync */
+ if (!fail)
+ synchronize_sched();
+ list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
+ __free_filter(filter_item->filter);
+ list_del(&filter_item->list);
+ kfree(filter_item);
+ }
+ return -ENOMEM;
+}
+
+static int create_filter_start(char *filter_str, bool set_str,
+ struct filter_parse_state **psp,
+ struct event_filter **filterp)
+{
+ struct event_filter *filter;
+ struct filter_parse_state *ps = NULL;
+ int err = 0;
+
+ WARN_ON_ONCE(*psp || *filterp);
+
+ /* allocate everything, and if any fails, free all and fail */
+ filter = __alloc_filter();
+ if (filter && set_str)
+ err = replace_filter_string(filter, filter_str);
+
+ ps = kzalloc(sizeof(*ps), GFP_KERNEL);
+
+ if (!filter || !ps || err) {
+ kfree(ps);
+ __free_filter(filter);
+ return -ENOMEM;
+ }
+
+ /* we're committed to creating a new filter */
+ *filterp = filter;
+ *psp = ps;
+
+ parse_init(ps, filter_ops, filter_str);
+ err = filter_parse(ps);
+ if (err && set_str)
+ append_filter_err(ps, filter);
+ return err;
+}
+
+static void create_filter_finish(struct filter_parse_state *ps)
+{
+ if (ps) {
+ filter_opstack_clear(ps);
+ postfix_clear(ps);
+ kfree(ps);
+ }
+}
+
+/**
+ * create_filter - create a filter for a ftrace_event_call
+ * @call: ftrace_event_call to create a filter for
+ * @filter_str: filter string
+ * @set_str: remember @filter_str and enable detailed error in filter
+ * @filterp: out param for created filter (always updated on return)
+ *
+ * Creates a filter for @call with @filter_str. If @set_str is %true,
+ * @filter_str is copied and recorded in the new filter.
+ *
+ * On success, returns 0 and *@filterp points to the new filter. On
+ * failure, returns -errno and *@filterp may point to %NULL or to a new
+ * filter. In the latter case, the returned filter contains error
+ * information if @set_str is %true and the caller is responsible for
+ * freeing it.
+ */
+static int create_filter(struct ftrace_event_call *call,
+ char *filter_str, bool set_str,
+ struct event_filter **filterp)
+{
+ struct event_filter *filter = NULL;
+ struct filter_parse_state *ps = NULL;
+ int err;
+
+ err = create_filter_start(filter_str, set_str, &ps, &filter);
+ if (!err) {
+ err = replace_preds(call, filter, ps, false);
+ if (err && set_str)
+ append_filter_err(ps, filter);
+ }
+ create_filter_finish(ps);
+
+ *filterp = filter;
+ return err;
+}
+
+int create_event_filter(struct ftrace_event_call *call,
+ char *filter_str, bool set_str,
+ struct event_filter **filterp)
+{
+ return create_filter(call, filter_str, set_str, filterp);
+}
+
+/**
+ * create_system_filter - create a filter for an event_subsystem
+ * @system: event_subsystem to create a filter for
+ * @filter_str: filter string
+ * @filterp: out param for created filter (always updated on return)
+ *
+ * Identical to create_filter() except that it creates a subsystem filter
+ * and always remembers @filter_str.
+ */
+static int create_system_filter(struct ftrace_subsystem_dir *dir,
+ struct trace_array *tr,
+ char *filter_str, struct event_filter **filterp)
+{
+ struct event_filter *filter = NULL;
+ struct filter_parse_state *ps = NULL;
+ int err;
+
+ err = create_filter_start(filter_str, true, &ps, &filter);
+ if (!err) {
+ err = replace_system_preds(dir, tr, ps, filter_str);
+ if (!err) {
+ /* System filters just show a default message */
+ kfree(filter->filter_string);
+ filter->filter_string = NULL;
+ } else {
+ append_filter_err(ps, filter);
+ }
+ }
+ create_filter_finish(ps);
+
+ *filterp = filter;
+ return err;
+}
+
+/* caller must hold event_mutex */
+int apply_event_filter(struct ftrace_event_file *file, char *filter_string)
+{
+ struct ftrace_event_call *call = file->event_call;
+ struct event_filter *filter;
+ int err;
+
+ if (!strcmp(strstrip(filter_string), "0")) {
+ filter_disable(file);
+ filter = event_filter(file);
+
+ if (!filter)
+ return 0;
+
+ event_clear_filter(file);
+
+ /* Make sure the filter is not being used */
+ synchronize_sched();
+ __free_filter(filter);
+
+ return 0;
+ }
+
+ err = create_filter(call, filter_string, true, &filter);
+
+ /*
+ * Always swap the call filter with the new filter
+ * even if there was an error. If there was an error
+ * in the filter, we disable the filter and show the error
+ * string
+ */
+ if (filter) {
+ struct event_filter *tmp;
+
+ tmp = event_filter(file);
+ if (!err)
+ event_set_filtered_flag(file);
+ else
+ filter_disable(file);
+
+ event_set_filter(file, filter);
+
+ if (tmp) {
+ /* Make sure the call is done with the filter */
+ synchronize_sched();
+ __free_filter(tmp);
+ }
+ }
+
+ return err;
+}
+
+int apply_subsystem_event_filter(struct ftrace_subsystem_dir *dir,
+ char *filter_string)
+{
+ struct event_subsystem *system = dir->subsystem;
+ struct trace_array *tr = dir->tr;
+ struct event_filter *filter;
+ int err = 0;
+
+ mutex_lock(&event_mutex);
+
+ /* Make sure the system still has events */
+ if (!dir->nr_events) {
+ err = -ENODEV;
+ goto out_unlock;
+ }
+
+ if (!strcmp(strstrip(filter_string), "0")) {
+ filter_free_subsystem_preds(dir, tr);
+ remove_filter_string(system->filter);
+ filter = system->filter;
+ system->filter = NULL;
+ /* Ensure all filters are no longer used */
+ synchronize_sched();
+ filter_free_subsystem_filters(dir, tr);
+ __free_filter(filter);
+ goto out_unlock;
+ }
+
+ err = create_system_filter(dir, tr, filter_string, &filter);
+ if (filter) {
+ /*
+ * No event actually uses the system filter
+ * we can free it without synchronize_sched().
+ */
+ __free_filter(system->filter);
+ system->filter = filter;
+ }
+out_unlock:
+ mutex_unlock(&event_mutex);
+
+ return err;
+}
+
+#ifdef CONFIG_PERF_EVENTS
+
+void ftrace_profile_free_filter(struct perf_event *event)
+{
+ struct event_filter *filter = event->filter;
+
+ event->filter = NULL;
+ __free_filter(filter);
+}
+
+struct function_filter_data {
+ struct ftrace_ops *ops;
+ int first_filter;
+ int first_notrace;
+};
+
+#ifdef CONFIG_FUNCTION_TRACER
+static char **
+ftrace_function_filter_re(char *buf, int len, int *count)
+{
+ char *str, *sep, **re;
+
+ str = kstrndup(buf, len, GFP_KERNEL);
+ if (!str)
+ return NULL;
+
+ /*
+ * The argv_split function takes white space
+ * as a separator, so convert ',' into spaces.
+ */
+ while ((sep = strchr(str, ',')))
+ *sep = ' ';
+
+ re = argv_split(GFP_KERNEL, str, count);
+ kfree(str);
+ return re;
+}
+
+static int ftrace_function_set_regexp(struct ftrace_ops *ops, int filter,
+ int reset, char *re, int len)
+{
+ int ret;
+
+ if (filter)
+ ret = ftrace_set_filter(ops, re, len, reset);
+ else
+ ret = ftrace_set_notrace(ops, re, len, reset);
+
+ return ret;
+}
+
+static int __ftrace_function_set_filter(int filter, char *buf, int len,
+ struct function_filter_data *data)
+{
+ int i, re_cnt, ret = -EINVAL;
+ int *reset;
+ char **re;
+
+ reset = filter ? &data->first_filter : &data->first_notrace;
+
+ /*
+ * The 'ip' field could have multiple filters set, separated
+ * either by space or comma. We first cut the filter and apply
+ * all pieces separatelly.
+ */
+ re = ftrace_function_filter_re(buf, len, &re_cnt);
+ if (!re)
+ return -EINVAL;
+
+ for (i = 0; i < re_cnt; i++) {
+ ret = ftrace_function_set_regexp(data->ops, filter, *reset,
+ re[i], strlen(re[i]));
+ if (ret)
+ break;
+
+ if (*reset)
+ *reset = 0;
+ }
+
+ argv_free(re);
+ return ret;
+}
+
+static int ftrace_function_check_pred(struct filter_pred *pred, int leaf)
+{
+ struct ftrace_event_field *field = pred->field;
+
+ if (leaf) {
+ /*
+ * Check the leaf predicate for function trace, verify:
+ * - only '==' and '!=' is used
+ * - the 'ip' field is used
+ */
+ if ((pred->op != OP_EQ) && (pred->op != OP_NE))
+ return -EINVAL;
+
+ if (strcmp(field->name, "ip"))
+ return -EINVAL;
+ } else {
+ /*
+ * Check the non leaf predicate for function trace, verify:
+ * - only '||' is used
+ */
+ if (pred->op != OP_OR)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ftrace_function_set_filter_cb(enum move_type move,
+ struct filter_pred *pred,
+ int *err, void *data)
+{
+ /* Checking the node is valid for function trace. */
+ if ((move != MOVE_DOWN) ||
+ (pred->left != FILTER_PRED_INVALID)) {
+ *err = ftrace_function_check_pred(pred, 0);
+ } else {
+ *err = ftrace_function_check_pred(pred, 1);
+ if (*err)
+ return WALK_PRED_ABORT;
+
+ *err = __ftrace_function_set_filter(pred->op == OP_EQ,
+ pred->regex.pattern,
+ pred->regex.len,
+ data);
+ }
+
+ return (*err) ? WALK_PRED_ABORT : WALK_PRED_DEFAULT;
+}
+
+static int ftrace_function_set_filter(struct perf_event *event,
+ struct event_filter *filter)
+{
+ struct function_filter_data data = {
+ .first_filter = 1,
+ .first_notrace = 1,
+ .ops = &event->ftrace_ops,
+ };
+
+ return walk_pred_tree(filter->preds, filter->root,
+ ftrace_function_set_filter_cb, &data);
+}
+#else
+static int ftrace_function_set_filter(struct perf_event *event,
+ struct event_filter *filter)
+{
+ return -ENODEV;
+}
+#endif /* CONFIG_FUNCTION_TRACER */
+
+int ftrace_profile_set_filter(struct perf_event *event, int event_id,
+ char *filter_str)
+{
+ int err;
+ struct event_filter *filter;
+ struct ftrace_event_call *call;
+
+ mutex_lock(&event_mutex);
+
+ call = event->tp_event;
+
+ err = -EINVAL;
+ if (!call)
+ goto out_unlock;
+
+ err = -EEXIST;
+ if (event->filter)
+ goto out_unlock;
+
+ err = create_filter(call, filter_str, false, &filter);
+ if (err)
+ goto free_filter;
+
+ if (ftrace_event_is_function(call))
+ err = ftrace_function_set_filter(event, filter);
+ else
+ event->filter = filter;
+
+free_filter:
+ if (err || ftrace_event_is_function(call))
+ __free_filter(filter);
+
+out_unlock:
+ mutex_unlock(&event_mutex);
+
+ return err;
+}
+
+#endif /* CONFIG_PERF_EVENTS */
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+#define CREATE_TRACE_POINTS
+#include "trace_events_filter_test.h"
+
+#define DATA_REC(m, va, vb, vc, vd, ve, vf, vg, vh, nvisit) \
+{ \
+ .filter = FILTER, \
+ .rec = { .a = va, .b = vb, .c = vc, .d = vd, \
+ .e = ve, .f = vf, .g = vg, .h = vh }, \
+ .match = m, \
+ .not_visited = nvisit, \
+}
+#define YES 1
+#define NO 0
+
+static struct test_filter_data_t {
+ char *filter;
+ struct ftrace_raw_ftrace_test_filter rec;
+ int match;
+ char *not_visited;
+} test_filter_data[] = {
+#define FILTER "a == 1 && b == 1 && c == 1 && d == 1 && " \
+ "e == 1 && f == 1 && g == 1 && h == 1"
+ DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, ""),
+ DATA_REC(NO, 0, 1, 1, 1, 1, 1, 1, 1, "bcdefgh"),
+ DATA_REC(NO, 1, 1, 1, 1, 1, 1, 1, 0, ""),
+#undef FILTER
+#define FILTER "a == 1 || b == 1 || c == 1 || d == 1 || " \
+ "e == 1 || f == 1 || g == 1 || h == 1"
+ DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 0, ""),
+ DATA_REC(YES, 0, 0, 0, 0, 0, 0, 0, 1, ""),
+ DATA_REC(YES, 1, 0, 0, 0, 0, 0, 0, 0, "bcdefgh"),
+#undef FILTER
+#define FILTER "(a == 1 || b == 1) && (c == 1 || d == 1) && " \
+ "(e == 1 || f == 1) && (g == 1 || h == 1)"
+ DATA_REC(NO, 0, 0, 1, 1, 1, 1, 1, 1, "dfh"),
+ DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
+ DATA_REC(YES, 1, 0, 1, 0, 0, 1, 0, 1, "bd"),
+ DATA_REC(NO, 1, 0, 1, 0, 0, 1, 0, 0, "bd"),
+#undef FILTER
+#define FILTER "(a == 1 && b == 1) || (c == 1 && d == 1) || " \
+ "(e == 1 && f == 1) || (g == 1 && h == 1)"
+ DATA_REC(YES, 1, 0, 1, 1, 1, 1, 1, 1, "efgh"),
+ DATA_REC(YES, 0, 0, 0, 0, 0, 0, 1, 1, ""),
+ DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 1, ""),
+#undef FILTER
+#define FILTER "(a == 1 && b == 1) && (c == 1 && d == 1) && " \
+ "(e == 1 && f == 1) || (g == 1 && h == 1)"
+ DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 0, "gh"),
+ DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 1, ""),
+ DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, ""),
+#undef FILTER
+#define FILTER "((a == 1 || b == 1) || (c == 1 || d == 1) || " \
+ "(e == 1 || f == 1)) && (g == 1 || h == 1)"
+ DATA_REC(YES, 1, 1, 1, 1, 1, 1, 0, 1, "bcdef"),
+ DATA_REC(NO, 0, 0, 0, 0, 0, 0, 0, 0, ""),
+ DATA_REC(YES, 1, 1, 1, 1, 1, 0, 1, 1, "h"),
+#undef FILTER
+#define FILTER "((((((((a == 1) && (b == 1)) || (c == 1)) && (d == 1)) || " \
+ "(e == 1)) && (f == 1)) || (g == 1)) && (h == 1))"
+ DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "ceg"),
+ DATA_REC(NO, 0, 1, 0, 1, 0, 1, 0, 1, ""),
+ DATA_REC(NO, 1, 0, 1, 0, 1, 0, 1, 0, ""),
+#undef FILTER
+#define FILTER "((((((((a == 1) || (b == 1)) && (c == 1)) || (d == 1)) && " \
+ "(e == 1)) || (f == 1)) && (g == 1)) || (h == 1))"
+ DATA_REC(YES, 1, 1, 1, 1, 1, 1, 1, 1, "bdfh"),
+ DATA_REC(YES, 0, 1, 0, 1, 0, 1, 0, 1, ""),
+ DATA_REC(YES, 1, 0, 1, 0, 1, 0, 1, 0, "bdfh"),
+};
+
+#undef DATA_REC
+#undef FILTER
+#undef YES
+#undef NO
+
+#define DATA_CNT (sizeof(test_filter_data)/sizeof(struct test_filter_data_t))
+
+static int test_pred_visited;
+
+static int test_pred_visited_fn(struct filter_pred *pred, void *event)
+{
+ struct ftrace_event_field *field = pred->field;
+
+ test_pred_visited = 1;
+ printk(KERN_INFO "\npred visited %s\n", field->name);
+ return 1;
+}
+
+static int test_walk_pred_cb(enum move_type move, struct filter_pred *pred,
+ int *err, void *data)
+{
+ char *fields = data;
+
+ if ((move == MOVE_DOWN) &&
+ (pred->left == FILTER_PRED_INVALID)) {
+ struct ftrace_event_field *field = pred->field;
+
+ if (!field) {
+ WARN(1, "all leafs should have field defined");
+ return WALK_PRED_DEFAULT;
+ }
+ if (!strchr(fields, *field->name))
+ return WALK_PRED_DEFAULT;
+
+ WARN_ON(!pred->fn);
+ pred->fn = test_pred_visited_fn;
+ }
+ return WALK_PRED_DEFAULT;
+}
+
+static __init int ftrace_test_event_filter(void)
+{
+ int i;
+
+ printk(KERN_INFO "Testing ftrace filter: ");
+
+ for (i = 0; i < DATA_CNT; i++) {
+ struct event_filter *filter = NULL;
+ struct test_filter_data_t *d = &test_filter_data[i];
+ int err;
+
+ err = create_filter(&event_ftrace_test_filter, d->filter,
+ false, &filter);
+ if (err) {
+ printk(KERN_INFO
+ "Failed to get filter for '%s', err %d\n",
+ d->filter, err);
+ __free_filter(filter);
+ break;
+ }
+
+ /*
+ * The preemption disabling is not really needed for self
+ * tests, but the rcu dereference will complain without it.
+ */
+ preempt_disable();
+ if (*d->not_visited)
+ walk_pred_tree(filter->preds, filter->root,
+ test_walk_pred_cb,
+ d->not_visited);
+
+ test_pred_visited = 0;
+ err = filter_match_preds(filter, &d->rec);
+ preempt_enable();
+
+ __free_filter(filter);
+
+ if (test_pred_visited) {
+ printk(KERN_INFO
+ "Failed, unwanted pred visited for filter %s\n",
+ d->filter);
+ break;
+ }
+
+ if (err != d->match) {
+ printk(KERN_INFO
+ "Failed to match filter '%s', expected %d\n",
+ d->filter, d->match);
+ break;
+ }
+ }
+
+ if (i == DATA_CNT)
+ printk(KERN_CONT "OK\n");
+
+ return 0;
+}
+
+late_initcall(ftrace_test_event_filter);
+
+#endif /* CONFIG_FTRACE_STARTUP_TEST */
Code Review / kvmfornfv.git / blobdiff