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|
// SPDX-License-Identifier: GPL-2.0
/*
* trace_events_filter - generic event filtering
*
* Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
*/
#include <linux/uaccess.h>
#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"
/* Due to token parsing '<=' must be before '<' and '>=' must be before '>' */
#define OPS \
C( OP_GLOB, "~" ), \
C( OP_NE, "!=" ), \
C( OP_EQ, "==" ), \
C( OP_LE, "<=" ), \
C( OP_LT, "<" ), \
C( OP_GE, ">=" ), \
C( OP_GT, ">" ), \
C( OP_BAND, "&" ), \
C( OP_MAX, NULL )
#undef C
#define C(a, b) a
enum filter_op_ids { OPS };
#undef C
#define C(a, b) b
static const char * ops[] = { OPS };
/*
* pred functions are OP_LE, OP_LT, OP_GE, OP_GT, and OP_BAND
* pred_funcs_##type below must match the order of them above.
*/
#define PRED_FUNC_START OP_LE
#define PRED_FUNC_MAX (OP_BAND - PRED_FUNC_START)
#define ERRORS \
C(NONE, "No error"), \
C(INVALID_OP, "Invalid operator"), \
C(TOO_MANY_OPEN, "Too many '('"), \
C(TOO_MANY_CLOSE, "Too few '('"), \
C(MISSING_QUOTE, "Missing matching quote"), \
C(OPERAND_TOO_LONG, "Operand too long"), \
C(EXPECT_STRING, "Expecting string field"), \
C(EXPECT_DIGIT, "Expecting numeric field"), \
C(ILLEGAL_FIELD_OP, "Illegal operation for field type"), \
C(FIELD_NOT_FOUND, "Field not found"), \
C(ILLEGAL_INTVAL, "Illegal integer value"), \
C(BAD_SUBSYS_FILTER, "Couldn't find or set field in one of a subsystem's events"), \
C(TOO_MANY_PREDS, "Too many terms in predicate expression"), \
C(INVALID_FILTER, "Meaningless filter expression"), \
C(IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \
C(INVALID_VALUE, "Invalid value (did you forget quotes)?"), \
C(ERRNO, "Error"), \
C(NO_FILTER, "No filter found")
#undef C
#define C(a, b) FILT_ERR_##a
enum { ERRORS };
#undef C
#define C(a, b) b
static const char *err_text[] = { ERRORS };
/* Called after a '!' character but "!=" and "!~" are not "not"s */
static bool is_not(const char *str)
{
switch (str[1]) {
case '=':
case '~':
return false;
}
return true;
}
/**
* prog_entry - a singe entry in the filter program
* @target: Index to jump to on a branch (actually one minus the index)
* @when_to_branch: The value of the result of the predicate to do a branch
* @pred: The predicate to execute.
*/
struct prog_entry {
int target;
int when_to_branch;
struct filter_pred *pred;
};
/**
* update_preds- assign a program entry a label target
* @prog: The program array
* @N: The index of the current entry in @prog
* @when_to_branch: What to assign a program entry for its branch condition
*
* The program entry at @N has a target that points to the index of a program
* entry that can have its target and when_to_branch fields updated.
* Update the current program entry denoted by index @N target field to be
* that of the updated entry. This will denote the entry to update if
* we are processing an "||" after an "&&"
*/
static void update_preds(struct prog_entry *prog, int N, int invert)
{
int t, s;
t = prog[N].target;
s = prog[t].target;
prog[t].when_to_branch = invert;
prog[t].target = N;
prog[N].target = s;
}
struct filter_parse_error {
int lasterr;
int lasterr_pos;
};
static void parse_error(struct filter_parse_error *pe, int err, int pos)
{
pe->lasterr = err;
pe->lasterr_pos = pos;
}
typedef int (*parse_pred_fn)(const char *str, void *data, int pos,
struct filter_parse_error *pe,
struct filter_pred **pred);
enum {
INVERT = 1,
PROCESS_AND = 2,
PROCESS_OR = 4,
};
/*
* Without going into a formal proof, this explains the method that is used in
* parsing the logical expressions.
*
* For example, if we have: "a && !(!b || (c && g)) || d || e && !f"
* The first pass will convert it into the following program:
*
* n1: r=a; l1: if (!r) goto l4;
* n2: r=b; l2: if (!r) goto l4;
* n3: r=c; r=!r; l3: if (r) goto l4;
* n4: r=g; r=!r; l4: if (r) goto l5;
* n5: r=d; l5: if (r) goto T
* n6: r=e; l6: if (!r) goto l7;
* n7: r=f; r=!r; l7: if (!r) goto F
* T: return TRUE
* F: return FALSE
*
* To do this, we use a data structure to represent each of the above
* predicate and conditions that has:
*
* predicate, when_to_branch, invert, target
*
* The "predicate" will hold the function to determine the result "r".
* The "when_to_branch" denotes what "r" should be if a branch is to be taken
* "&&" would contain "!r" or (0) and "||" would contain "r" or (1).
* The "invert" holds whether the value should be reversed before testing.
* The "target" contains the label "l#" to jump to.
*
* A stack is created to hold values when parentheses are used.
*
* To simplify the logic, the labels will start at 0 and not 1.
*
* The possible invert values are 1 and 0. The number of "!"s that are in scope
* before the predicate determines the invert value, if the number is odd then
* the invert value is 1 and 0 otherwise. This means the invert value only
* needs to be toggled when a new "!" is introduced compared to what is stored
* on the stack, where parentheses were used.
*
* The top of the stack and "invert" are initialized to zero.
*
* ** FIRST PASS **
*
* #1 A loop through all the tokens is done:
*
* #2 If the token is an "(", the stack is push, and the current stack value
* gets the current invert value, and the loop continues to the next token.
* The top of the stack saves the "invert" value to keep track of what
* the current inversion is. As "!(a && !b || c)" would require all
* predicates being affected separately by the "!" before the parentheses.
* And that would end up being equivalent to "(!a || b) && !c"
*
* #3 If the token is an "!", the current "invert" value gets inverted, and
* the loop continues. Note, if the next token is a predicate, then
* this "invert" value is only valid for the current program entry,
* and does not affect other predicates later on.
*
* The only other acceptable token is the predicate string.
*
* #4 A new entry into the program is added saving: the predicate and the
* current value of "invert". The target is currently assigned to the
* previous program index (this will not be its final value).
*
* #5 We now enter another loop and look at the next token. The only valid
* tokens are ")", "&&", "||" or end of the input string "\0".
*
* #6 The invert variable is reset to the current value saved on the top of
* the stack.
*
* #7 The top of the stack holds not only the current invert value, but also
* if a "&&" or "||" needs to be processed. Note, the "&&" takes higher
* precedence than "||". That is "a && b || c && d" is equivalent to
* "(a && b) || (c && d)". Thus the first thing to do is to see if "&&" needs
* to be processed. This is the case if an "&&" was the last token. If it was
* then we call update_preds(). This takes the program, the current index in
* the program, and the current value of "invert". More will be described
* below about this function.
*
* #8 If the next token is "&&" then we set a flag in the top of the stack
* that denotes that "&&" needs to be processed, break out of this loop
* and continue with the outer loop.
*
* #9 Otherwise, if a "||" needs to be processed then update_preds() is called.
* This is called with the program, the current index in the program, but
* this time with an inverted value of "invert" (that is !invert). This is
* because the value taken will become the "when_to_branch" value of the
* program.
* Note, this is called when the next token is not an "&&". As stated before,
* "&&" takes higher precedence, and "||" should not be processed yet if the
* next logical operation is "&&".
*
* #10 If the next token is "||" then we set a flag in the top of the stack
* that denotes that "||" needs to be processed, break out of this loop
* and continue with the outer loop.
*
* #11 If this is the end of the input string "\0" then we break out of both
* loops.
*
* #12 Otherwise, the next token is ")", where we pop the stack and continue
* this inner loop.
*
* Now to discuss the update_pred() function, as that is key to the setting up
* of the program. Remember the "target" of the program is initialized to the
* previous index and not the "l" label. The target holds the index into the
* program that gets affected by the operand. Thus if we have something like
* "a || b && c", when we process "a" the target will be "-1" (undefined).
* When we process "b", its target is "0", which is the index of "a", as that's
* the predicate that is affected by "||". But because the next token after "b"
* is "&&" we don't call update_preds(). Instead continue to "c". As the
* next token after "c" is not "&&" but the end of input, we first process the
* "&&" by calling update_preds() for the "&&" then we process the "||" by
* callin updates_preds() with the values for processing "||".
*
* What does that mean? What update_preds() does is to first save the "target"
* of the program entry indexed by the current program entry's "target"
* (remember the "target" is initialized to previous program entry), and then
* sets that "target" to the current index which represents the label "l#".
* That entry's "when_to_branch" is set to the value passed in (the "invert"
* or "!invert"). Then it sets the current program entry's target to the saved
* "target" value (the old value of the program that had its "target" updated
* to the label).
*
* Looking back at "a || b && c", we have the following steps:
* "a" - prog[0] = { "a", X, -1 } // pred, when_to_branch, target
* "||" - flag that we need to process "||"; continue outer loop
* "b" - prog[1] = { "b", X, 0 }
* "&&" - flag that we need to process "&&"; continue outer loop
* (Notice we did not process "||")
* "c" - prog[2] = { "c", X, 1 }
* update_preds(prog, 2, 0); // invert = 0 as we are processing "&&"
* t = prog[2].target; // t = 1
* s = prog[t].target; // s = 0
* prog[t].target = 2; // Set target to "l2"
* prog[t].when_to_branch = 0;
* prog[2].target = s;
* update_preds(prog, 2, 1); // invert = 1 as we are now processing "||"
* t = prog[2].target; // t = 0
* s = prog[t].target; // s = -1
* prog[t].target = 2; // Set target to "l2"
* prog[t].when_to_branch = 1;
* prog[2].target = s;
*
* #13 Which brings us to the final step of the first pass, which is to set
* the last program entry's when_to_branch and target, which will be
* when_to_branch = 0; target = N; ( the label after the program entry after
* the last program entry processed above).
*
* If we denote "TRUE" to be the entry after the last program entry processed,
* and "FALSE" the program entry after that, we are now done with the first
* pass.
*
* Making the above "a || b && c" have a progam of:
* prog[0] = { "a", 1, 2 }
* prog[1] = { "b", 0, 2 }
* prog[2] = { "c", 0, 3 }
*
* Which translates into:
* n0: r = a; l0: if (r) goto l2;
* n1: r = b; l1: if (!r) goto l2;
* n2: r = c; l2: if (!r) goto l3; // Which is the same as "goto F;"
* T: return TRUE; l3:
* F: return FALSE
*
* Although, after the first pass, the program is correct, it is
* inefficient. The simple sample of "a || b && c" could be easily been
* converted into:
* n0: r = a; if (r) goto T
* n1: r = b; if (!r) goto F
* n2: r = c; if (!r) goto F
* T: return TRUE;
* F: return FALSE;
*
* The First Pass is over the input string. The next too passes are over
* the program itself.
*
* ** SECOND PASS **
*
* Which brings us to the second pass. If a jump to a label has the
* same condition as that label, it can instead jump to its target.
* The original example of "a && !(!b || (c && g)) || d || e && !f"
* where the first pass gives us:
*
* n1: r=a; l1: if (!r) goto l4;
* n2: r=b; l2: if (!r) goto l4;
* n3: r=c; r=!r; l3: if (r) goto l4;
* n4: r=g; r=!r; l4: if (r) goto l5;
* n5: r=d; l5: if (r) goto T
* n6: r=e; l6: if (!r) goto l7;
* n7: r=f; r=!r; l7: if (!r) goto F:
* T: return TRUE;
* F: return FALSE
*
* We can see that "l3: if (r) goto l4;" and at l4, we have "if (r) goto l5;".
* And "l5: if (r) goto T", we could optimize this by converting l3 and l4
* to go directly to T. To accomplish this, we start from the last
* entry in the program and work our way back. If the target of the entry
* has the same "when_to_branch" then we could use that entry's target.
* Doing this, the above would end up as:
*
* n1: r=a; l1: if (!r) goto l4;
* n2: r=b; l2: if (!r) goto l4;
* n3: r=c; r=!r; l3: if (r) goto T;
* n4: r=g; r=!r; l4: if (r) goto T;
* n5: r=d; l5: if (r) goto T;
* n6: r=e; l6: if (!r) goto F;
* n7: r=f; r=!r; l7: if (!r) goto F;
* T: return TRUE
* F: return FALSE
*
* In that same pass, if the "when_to_branch" doesn't match, we can simply
* go to the program entry after the label. That is, "l2: if (!r) goto l4;"
* where "l4: if (r) goto T;", then we can convert l2 to be:
* "l2: if (!r) goto n5;".
*
* This will have the second pass give us:
* n1: r=a; l1: if (!r) goto n5;
* n2: r=b; l2: if (!r) goto n5;
* n3: r=c; r=!r; l3: if (r) goto T;
* n4: r=g; r=!r; l4: if (r) goto T;
* n5: r=d; l5: if (r) goto T
* n6: r=e; l6: if (!r) goto F;
* n7: r=f; r=!r; l7: if (!r) goto F
* T: return TRUE
* F: return FALSE
*
* Notice, all the "l#" labels are no longer used, and they can now
* be discarded.
*
* ** THIRD PASS **
*
* For the third pass we deal with the inverts. As they simply just
* make the "when_to_branch" get inverted, a simple loop over the
* program to that does: "when_to_branch ^= invert;" will do the
* job, leaving us with:
* n1: r=a; if (!r) goto n5;
* n2: r=b; if (!r) goto n5;
* n3: r=c: if (!r) goto T;
* n4: r=g; if (!r) goto T;
* n5: r=d; if (r) goto T
* n6: r=e; if (!r) goto F;
* n7: r=f; if (r) goto F
* T: return TRUE
* F: return FALSE
*
* As "r = a; if (!r) goto n5;" is obviously the same as
* "if (!a) goto n5;" without doing anything we can interperate the
* program as:
* n1: if (!a) goto n5;
* n2: if (!b) goto n5;
* n3: if (!c) goto T;
* n4: if (!g) goto T;
* n5: if (d) goto T
* n6: if (!e) goto F;
* n7: if (f) goto F
* T: return TRUE
* F: return FALSE
*
* Since the inverts are discarded at the end, there's no reason to store
* them in the program array (and waste memory). A separate array to hold
* the inverts is used and freed at the end.
*/
static struct prog_entry *
predicate_parse(const char *str, int nr_parens, int nr_preds,
parse_pred_fn parse_pred, void *data,
struct filter_parse_error *pe)
{
struct prog_entry *prog_stack;
struct prog_entry *prog;
const char *ptr = str;
char *inverts = NULL;
int *op_stack;
int *top;
int invert = 0;
int ret = -ENOMEM;
int len;
int N = 0;
int i;
nr_preds += 2; /* For TRUE and FALSE */
op_stack = kmalloc_array(nr_parens, sizeof(*op_stack), GFP_KERNEL);
if (!op_stack)
return ERR_PTR(-ENOMEM);
prog_stack = kcalloc(nr_preds, sizeof(*prog_stack), GFP_KERNEL);
if (!prog_stack) {
parse_error(pe, -ENOMEM, 0);
goto out_free;
}
inverts = kmalloc_array(nr_preds, sizeof(*inverts), GFP_KERNEL);
if (!inverts) {
parse_error(pe, -ENOMEM, 0);
goto out_free;
}
top = op_stack;
prog = prog_stack;
*top = 0;
/* First pass */
while (*ptr) { /* #1 */
const char *next = ptr++;
if (isspace(*next))
continue;
switch (*next) {
case '(': /* #2 */
if (top - op_stack > nr_parens) {
ret = -EINVAL;
goto out_free;
}
*(++top) = invert;
continue;
case '!': /* #3 */
if (!is_not(next))
break;
invert = !invert;
continue;
}
if (N >= nr_preds) {
parse_error(pe, FILT_ERR_TOO_MANY_PREDS, next - str);
goto out_free;
}
inverts[N] = invert; /* #4 */
prog[N].target = N-1;
len = parse_pred(next, data, ptr - str, pe, &prog[N].pred);
if (len < 0) {
ret = len;
goto out_free;
}
ptr = next + len;
N++;
ret = -1;
while (1) { /* #5 */
next = ptr++;
if (isspace(*next))
continue;
switch (*next) {
case ')':
case '\0':
break;
case '&':
case '|':
/* accepting only "&&" or "||" */
if (next[1] == next[0]) {
ptr++;
break;
}
fallthrough;
default:
parse_error(pe, FILT_ERR_TOO_MANY_PREDS,
next - str);
goto out_free;
}
invert = *top & INVERT;
if (*top & PROCESS_AND) { /* #7 */
update_preds(prog, N - 1, invert);
*top &= ~PROCESS_AND;
}
if (*next == '&') { /* #8 */
*top |= PROCESS_AND;
break;
}
if (*top & PROCESS_OR) { /* #9 */
update_preds(prog, N - 1, !invert);
*top &= ~PROCESS_OR;
}
if (*next == '|') { /* #10 */
*top |= PROCESS_OR;
break;
}
if (!*next) /* #11 */
goto out;
if (top == op_stack) {
ret = -1;
/* Too few '(' */
parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, ptr - str);
goto out_free;
}
top--; /* #12 */
}
}
out:
if (top != op_stack) {
/* Too many '(' */
parse_error(pe, FILT_ERR_TOO_MANY_OPEN, ptr - str);
goto out_free;
}
if (!N) {
/* No program? */
ret = -EINVAL;
parse_error(pe, FILT_ERR_NO_FILTER, ptr - str);
goto out_free;
}
prog[N].pred = NULL; /* #13 */
prog[N].target = 1; /* TRUE */
prog[N+1].pred = NULL;
prog[N+1].target = 0; /* FALSE */
prog[N-1].target = N;
prog[N-1].when_to_branch = false;
/* Second Pass */
for (i = N-1 ; i--; ) {
int target = prog[i].target;
if (prog[i].when_to_branch == prog[target].when_to_branch)
prog[i].target = prog[target].target;
}
/* Third Pass */
for (i = 0; i < N; i++) {
invert = inverts[i] ^ prog[i].when_to_branch;
prog[i].when_to_branch = invert;
/* Make sure the program always moves forward */
if (WARN_ON(prog[i].target <= i)) {
ret = -EINVAL;
goto out_free;
}
}
kfree(op_stack);
kfree(inverts);
return prog;
out_free:
kfree(op_stack);
kfree(inverts);
if (prog_stack) {
for (i = 0; prog_stack[i].pred; i++)
kfree(prog_stack[i].pred);
kfree(prog_stack);
}
return ERR_PTR(ret);
}
#define DEFINE_COMPARISON_PRED(type) \
static int filter_pred_LT_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
return *addr < val; \
} \
static int filter_pred_LE_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
return *addr <= val; \
} \
static int filter_pred_GT_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
return *addr > val; \
} \
static int filter_pred_GE_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
return *addr >= val; \
} \
static int filter_pred_BAND_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
return !!(*addr & val); \
} \
static const filter_pred_fn_t pred_funcs_##type[] = { \
filter_pred_LE_##type, \
filter_pred_LT_##type, \
filter_pred_GE_##type, \
filter_pred_GT_##type, \
filter_pred_BAND_##type, \
};
#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);
/* user space strings temp buffer */
#define USTRING_BUF_SIZE 1024
struct ustring_buffer {
char buffer[USTRING_BUF_SIZE];
};
static __percpu struct ustring_buffer *ustring_per_cpu;
static __always_inline char *test_string(char *str)
{
struct ustring_buffer *ubuf;
char *kstr;
if (!ustring_per_cpu)
return NULL;
ubuf = this_cpu_ptr(ustring_per_cpu);
kstr = ubuf->buffer;
/* For safety, do not trust the string pointer */
if (!strncpy_from_kernel_nofault(kstr, str, USTRING_BUF_SIZE))
return NULL;
return kstr;
}
static __always_inline char *test_ustring(char *str)
{
struct ustring_buffer *ubuf;
char __user *ustr;
char *kstr;
if (!ustring_per_cpu)
return NULL;
ubuf = this_cpu_ptr(ustring_per_cpu);
kstr = ubuf->buffer;
/* user space address? */
ustr = (char __user *)str;
if (!strncpy_from_user_nofault(kstr, ustr, USTRING_BUF_SIZE))
return NULL;
return kstr;
}
/* 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;
}
static __always_inline int filter_pchar(struct filter_pred *pred, char *str)
{
int cmp, match;
int len;
len = strlen(str) + 1; /* including tailing '\0' */
cmp = pred->regex.match(str, &pred->regex, 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);
char *str;
str = test_string(*addr);
if (!str)
return 0;
return filter_pchar(pred, str);
}
/* Filter predicate for char * pointers in user space*/
static int filter_pred_pchar_user(struct filter_pred *pred, void *event)
{
char **addr = (char **)(event + pred->offset);
char *str;
str = test_ustring(*addr);
if (!str)
return 0;
return filter_pchar(pred, str);
}
/*
* 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;
}
/* Filter predicate for CPUs. */
static int filter_pred_cpu(struct filter_pred *pred, void *event)
{
int cpu, cmp;
cpu = raw_smp_processor_id();
cmp = pred->val;
switch (pred->op) {
case OP_EQ:
return cpu == cmp;
case OP_NE:
return cpu != cmp;
case OP_LT:
return cpu < cmp;
case OP_LE:
return cpu <= cmp;
case OP_GT:
return cpu > cmp;
case OP_GE:
return cpu >= cmp;
default:
return 0;
}
}
/* Filter predicate for COMM. */
static int filter_pred_comm(struct filter_pred *pred, void *event)
{
int cmp;
cmp = pred->regex.match(current->comm, &pred->regex,
TASK_COMM_LEN);
return cmp ^ pred->not;
}
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, unless @len is zero.
*/
static int regex_match_full(char *str, struct regex *r, int len)
{
/* len of zero means str is dynamic and ends with '\0' */
if (!len)
return strcmp(str, r->pattern) == 0;
return strncmp(str, r->pattern, len) == 0;
}
static int regex_match_front(char *str, struct regex *r, int len)
{
if (len && len < r->len)
return 0;
return strncmp(str, r->pattern, r->len) == 0;
}
static int regex_match_middle(char *str, struct regex *r, int len)
{
if (!len)
return strstr(str, r->pattern) != NULL;
return strnstr(str, r->pattern, len) != NULL;
}
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;
}
static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
{
if (glob_match(r->pattern, str))
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;
if (isdigit(buff[0]))
return MATCH_INDEX;
for (i = 0; i < len; i++) {
if (buff[i] == '*') {
if (!i) {
type = MATCH_END_ONLY;
} else if (i == len - 1) {
if (type == MATCH_END_ONLY)
type = MATCH_MIDDLE_ONLY;
else
type = MATCH_FRONT_ONLY;
buff[i] = 0;
break;
} else { /* pattern continues, use full glob */
return MATCH_GLOB;
}
} else if (strchr("[?\\", buff[i])) {
return MATCH_GLOB;
}
}
if (buff[0] == '*')
*search = buff + 1;
return type;
}
static void filter_build_regex(struct filter_pred *pred)
{
struct regex *r = &pred->regex;
char *search;
enum regex_type type = MATCH_FULL;
if (pred->op == OP_GLOB) {
type = filter_parse_regex(r->pattern, r->len, &search, &pred->not);
r->len = strlen(search);
memmove(r->pattern, search, r->len+1);
}
switch (type) {
/* MATCH_INDEX should not happen, but if it does, match full */
case MATCH_INDEX:
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;
case MATCH_GLOB:
r->match = regex_match_glob;
break;
}
}
/* return 1 if event matches, 0 otherwise (discard) */
int filter_match_preds(struct event_filter *filter, void *rec)
{
struct prog_entry *prog;
int i;
/* no filter is considered a match */
if (!filter)
return 1;
/* Protected by either SRCU(tracepoint_srcu) or preempt_disable */
prog = rcu_dereference_raw(filter->prog);
if (!prog)
return 1;
for (i = 0; prog[i].pred; i++) {
struct filter_pred *pred = prog[i].pred;
int match = pred->fn(pred, rec);
if (match == prog[i].when_to_branch)
i = prog[i].target;
}
return prog[i].target;
}
EXPORT_SYMBOL_GPL(filter_match_preds);
static void remove_filter_string(struct event_filter *filter)
{
if (!filter)
return;
kfree(filter->filter_string);
filter->filter_string = NULL;
}
static void append_filter_err(struct trace_array *tr,
struct filter_parse_error *pe,
struct event_filter *filter)
{
struct trace_seq *s;
int pos = pe->lasterr_pos;
char *buf;
int len;
if (WARN_ON(!filter->filter_string))
return;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (!s)
return;
trace_seq_init(s);
len = strlen(filter->filter_string);
if (pos > len)
pos = len;
/* indexing is off by one */
if (pos)
pos++;
trace_seq_puts(s, filter->filter_string);
if (pe->lasterr > 0) {
trace_seq_printf(s, "\n%*s", pos, "^");
trace_seq_printf(s, "\nparse_error: %s\n", err_text[pe->lasterr]);
tracing_log_err(tr, "event filter parse error",
filter->filter_string, err_text,
pe->lasterr, pe->lasterr_pos);
} else {
trace_seq_printf(s, "\nError: (%d)\n", pe->lasterr);
tracing_log_err(tr, "event filter parse error",
filter->filter_string, err_text,
FILT_ERR_ERRNO, 0);
}
trace_seq_putc(s, 0);
buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL);
if (buf) {
kfree(filter->filter_string);
filter->filter_string = buf;
}
kfree(s);
}
static inline struct event_filter *event_filter(struct trace_event_file *file)
{
return file->filter;
}
/* caller must hold event_mutex */
void print_event_filter(struct trace_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 void free_prog(struct event_filter *filter)
{
struct prog_entry *prog;
int i;
prog = rcu_access_pointer(filter->prog);
if (!prog)
return;
for (i = 0; prog[i].pred; i++)
kfree(prog[i].pred);
kfree(prog);
}
static void filter_disable(struct trace_event_file *file)
{
unsigned long old_flags = file->flags;
file->flags &= ~EVENT_FILE_FL_FILTERED;
if (old_flags != file->flags)
trace_buffered_event_disable();
}
static void __free_filter(struct event_filter *filter)
{
if (!filter)
return;
free_prog(filter);
kfree(filter->filter_string);
kfree(filter);
}
void free_event_filter(struct event_filter *filter)
{
__free_filter(filter);
}
static inline void __remove_filter(struct trace_event_file *file)
{
filter_disable(file);
remove_filter_string(file->filter);
}
static void filter_free_subsystem_preds(struct trace_subsystem_dir *dir,
struct trace_array *tr)
{
struct trace_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 trace_event_file *file)
{
__free_filter(file->filter);
file->filter = NULL;
}
static void filter_free_subsystem_filters(struct trace_subsystem_dir *dir,
struct trace_array *tr)
{
struct trace_event_file *file;
list_for_each_entry(file, &tr->events, list) {
if (file->system != dir)
continue;
__free_subsystem_filter(file);
}
}
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;
if (strcmp(type, "char *") == 0 || strcmp(type, "const char *") == 0)
return FILTER_PTR_STRING;
return FILTER_OTHER;
}
static filter_pred_fn_t select_comparison_fn(enum filter_op_ids op,
int field_size, int field_is_signed)
{
filter_pred_fn_t fn = NULL;
int pred_func_index = -1;
switch (op) {
case OP_EQ:
case OP_NE:
break;
default:
if (WARN_ON_ONCE(op < PRED_FUNC_START))
return NULL;
pred_func_index = op - PRED_FUNC_START;
if (WARN_ON_ONCE(pred_func_index > PRED_FUNC_MAX))
return NULL;
}
switch (field_size) {
case 8:
if (pred_func_index < 0)
fn = filter_pred_64;
else if (field_is_signed)
fn = pred_funcs_s64[pred_func_index];
else
fn = pred_funcs_u64[pred_func_index];
break;
case 4:
if (pred_func_index < 0)
fn = filter_pred_32;
else if (field_is_signed)
fn = pred_funcs_s32[pred_func_index];
else
fn = pred_funcs_u32[pred_func_index];
break;
case 2:
if (pred_func_index < 0)
fn = filter_pred_16;
else if (field_is_signed)
fn = pred_funcs_s16[pred_func_index];
else
fn = pred_funcs_u16[pred_func_index];
break;
case 1:
if (pred_func_index < 0)
fn = filter_pred_8;
else if (field_is_signed)
fn = pred_funcs_s8[pred_func_index];
else
fn = pred_funcs_u8[pred_func_index];
break;
}
return fn;
}
/* Called when a predicate is encountered by predicate_parse() */
static int parse_pred(const char *str, void *data,
int pos, struct filter_parse_error *pe,
struct filter_pred **pred_ptr)
{
struct trace_event_call *call = data;
struct ftrace_event_field *field;
struct filter_pred *pred = NULL;
char num_buf[24]; /* Big enough to hold an address */
char *field_name;
bool ustring = false;
char q;
u64 val;
int len;
int ret;
int op;
int s;
int i = 0;
/* First find the field to associate to */
while (isspace(str[i]))
i++;
s = i;
while (isalnum(str[i]) || str[i] == '_')
i++;
len = i - s;
if (!len)
return -1;
field_name = kmemdup_nul(str + s, len, GFP_KERNEL);
if (!field_name)
return -ENOMEM;
/* Make sure that the field exists */
field = trace_find_event_field(call, field_name);
kfree(field_name);
if (!field) {
parse_error(pe, FILT_ERR_FIELD_NOT_FOUND, pos + i);
return -EINVAL;
}
/* See if the field is a user space string */
if ((len = str_has_prefix(str + i, ".ustring"))) {
ustring = true;
i += len;
}
while (isspace(str[i]))
i++;
/* Make sure this op is supported */
for (op = 0; ops[op]; op++) {
/* This is why '<=' must come before '<' in ops[] */
if (strncmp(str + i, ops[op], strlen(ops[op])) == 0)
break;
}
if (!ops[op]) {
parse_error(pe, FILT_ERR_INVALID_OP, pos + i);
goto err_free;
}
i += strlen(ops[op]);
while (isspace(str[i]))
i++;
s = i;
pred = kzalloc(sizeof(*pred), GFP_KERNEL);
if (!pred)
return -ENOMEM;
pred->field = field;
pred->offset = field->offset;
pred->op = op;
if (ftrace_event_is_function(call)) {
/*
* Perf does things different with function events.
* It only allows an "ip" field, and expects a string.
* But the string does not need to be surrounded by quotes.
* If it is a string, the assigned function as a nop,
* (perf doesn't use it) and grab everything.
*/
if (strcmp(field->name, "ip") != 0) {
parse_error(pe, FILT_ERR_IP_FIELD_ONLY, pos + i);
goto err_free;
}
pred->fn = filter_pred_none;
/*
* Quotes are not required, but if they exist then we need
* to read them till we hit a matching one.
*/
if (str[i] == '\'' || str[i] == '"')
q = str[i];
else
q = 0;
for (i++; str[i]; i++) {
if (q && str[i] == q)
break;
if (!q && (str[i] == ')' || str[i] == '&' ||
str[i] == '|'))
break;
}
/* Skip quotes */
if (q)
s++;
len = i - s;
if (len >= MAX_FILTER_STR_VAL) {
parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
goto err_free;
}
pred->regex.len = len;
strncpy(pred->regex.pattern, str + s, len);
pred->regex.pattern[len] = 0;
/* This is either a string, or an integer */
} else if (str[i] == '\'' || str[i] == '"') {
char q = str[i];
/* Make sure the op is OK for strings */
switch (op) {
case OP_NE:
pred->not = 1;
fallthrough;
case OP_GLOB:
case OP_EQ:
break;
default:
parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
goto err_free;
}
/* Make sure the field is OK for strings */
if (!is_string_field(field)) {
parse_error(pe, FILT_ERR_EXPECT_DIGIT, pos + i);
goto err_free;
}
for (i++; str[i]; i++) {
if (str[i] == q)
break;
}
if (!str[i]) {
parse_error(pe, FILT_ERR_MISSING_QUOTE, pos + i);
goto err_free;
}
/* Skip quotes */
s++;
len = i - s;
if (len >= MAX_FILTER_STR_VAL) {
parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
goto err_free;
}
pred->regex.len = len;
strncpy(pred->regex.pattern, str + s, len);
pred->regex.pattern[len] = 0;
filter_build_regex(pred);
if (field->filter_type == FILTER_COMM) {
pred->fn = filter_pred_comm;
} else if (field->filter_type == FILTER_STATIC_STRING) {
pred->fn = filter_pred_string;
pred->regex.field_len = field->size;
} else if (field->filter_type == FILTER_DYN_STRING)
pred->fn = filter_pred_strloc;
else {
if (!ustring_per_cpu) {
/* Once allocated, keep it around for good */
ustring_per_cpu = alloc_percpu(struct ustring_buffer);
if (!ustring_per_cpu)
goto err_mem;
}
if (ustring)
pred->fn = filter_pred_pchar_user;
else
pred->fn = filter_pred_pchar;
}
/* go past the last quote */
i++;
} else if (isdigit(str[i]) || str[i] == '-') {
/* Make sure the field is not a string */
if (is_string_field(field)) {
parse_error(pe, FILT_ERR_EXPECT_STRING, pos + i);
goto err_free;
}
if (op == OP_GLOB) {
parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
goto err_free;
}
if (str[i] == '-')
i++;
/* We allow 0xDEADBEEF */
while (isalnum(str[i]))
i++;
len = i - s;
/* 0xfeedfacedeadbeef is 18 chars max */
if (len >= sizeof(num_buf)) {
parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
goto err_free;
}
strncpy(num_buf, str + s, len);
num_buf[len] = 0;
/* Make sure it is a value */
if (field->is_signed)
ret = kstrtoll(num_buf, 0, &val);
else
ret = kstrtoull(num_buf, 0, &val);
if (ret) {
parse_error(pe, FILT_ERR_ILLEGAL_INTVAL, pos + s);
goto err_free;
}
pred->val = val;
if (field->filter_type == FILTER_CPU)
pred->fn = filter_pred_cpu;
else {
pred->fn = select_comparison_fn(pred->op, field->size,
field->is_signed);
if (pred->op == OP_NE)
pred->not = 1;
}
} else {
parse_error(pe, FILT_ERR_INVALID_VALUE, pos + i);
goto err_free;
}
*pred_ptr = pred;
return i;
err_free:
kfree(pred);
return -EINVAL;
err_mem:
kfree(pred);
return -ENOMEM;
}
enum {
TOO_MANY_CLOSE = -1,
TOO_MANY_OPEN = -2,
MISSING_QUOTE = -3,
};
/*
* Read the filter string once to calculate the number of predicates
* as well as how deep the parentheses go.
*
* Returns:
* 0 - everything is fine (err is undefined)
* -1 - too many ')'
* -2 - too many '('
* -3 - No matching quote
*/
static int calc_stack(const char *str, int *parens, int *preds, int *err)
{
bool is_pred = false;
int nr_preds = 0;
int open = 1; /* Count the expression as "(E)" */
int last_quote = 0;
int max_open = 1;
int quote = 0;
int i;
*err = 0;
for (i = 0; str[i]; i++) {
if (isspace(str[i]))
continue;
if (quote) {
if (str[i] == quote)
quote = 0;
continue;
}
switch (str[i]) {
case '\'':
case '"':
quote = str[i];
last_quote = i;
break;
case '|':
case '&':
if (str[i+1] != str[i])
break;
is_pred = false;
continue;
case '(':
is_pred = false;
open++;
if (open > max_open)
max_open = open;
continue;
case ')':
is_pred = false;
if (open == 1) {
*err = i;
return TOO_MANY_CLOSE;
}
open--;
continue;
}
if (!is_pred) {
nr_preds++;
is_pred = true;
}
}
if (quote) {
*err = last_quote;
return MISSING_QUOTE;
}
if (open != 1) {
int level = open;
/* find the bad open */
for (i--; i; i--) {
if (quote) {
if (str[i] == quote)
quote = 0;
continue;
}
switch (str[i]) {
case '(':
if (level == open) {
*err = i;
return TOO_MANY_OPEN;
}
level--;
break;
case ')':
level++;
break;
case '\'':
case '"':
quote = str[i];
break;
}
}
/* First character is the '(' with missing ')' */
*err = 0;
return TOO_MANY_OPEN;
}
/* Set the size of the required stacks */
*parens = max_open;
*preds = nr_preds;
return 0;
}
static int process_preds(struct trace_event_call *call,
const char *filter_string,
struct event_filter *filter,
struct filter_parse_error *pe)
{
struct prog_entry *prog;
int nr_parens;
int nr_preds;
int index;
int ret;
ret = calc_stack(filter_string, &nr_parens, &nr_preds, &index);
if (ret < 0) {
switch (ret) {
case MISSING_QUOTE:
parse_error(pe, FILT_ERR_MISSING_QUOTE, index);
break;
case TOO_MANY_OPEN:
parse_error(pe, FILT_ERR_TOO_MANY_OPEN, index);
break;
default:
parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, index);
}
return ret;
}
if (!nr_preds)
return -EINVAL;
prog = predicate_parse(filter_string, nr_parens, nr_preds,
parse_pred, call, pe);
if (IS_ERR(prog))
return PTR_ERR(prog);
rcu_assign_pointer(filter->prog, prog);
return 0;
}
static inline void event_set_filtered_flag(struct trace_event_file *file)
{
unsigned long old_flags = file->flags;
file->flags |= EVENT_FILE_FL_FILTERED;
if (old_flags != file->flags)
trace_buffered_event_enable();
}
static inline void event_set_filter(struct trace_event_file *file,
struct event_filter *filter)
{
rcu_assign_pointer(file->filter, filter);
}
static inline void event_clear_filter(struct trace_event_file *file)
{
RCU_INIT_POINTER(file->filter, NULL);
}
static inline void
event_set_no_set_filter_flag(struct trace_event_file *file)
{
file->flags |= EVENT_FILE_FL_NO_SET_FILTER;
}
static inline void
event_clear_no_set_filter_flag(struct trace_event_file *file)
{
file->flags &= ~EVENT_FILE_FL_NO_SET_FILTER;
}
static inline bool
event_no_set_filter_flag(struct trace_event_file *file)
{
if (file->flags & EVENT_FILE_FL_NO_SET_FILTER)
return true;
return false;
}
struct filter_list {
struct list_head list;
struct event_filter *filter;
};
static int process_system_preds(struct trace_subsystem_dir *dir,
struct trace_array *tr,
struct filter_parse_error *pe,
char *filter_string)
{
struct trace_event_file *file;
struct filter_list *filter_item;
struct event_filter *filter = NULL;
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;
filter = kzalloc(sizeof(*filter), GFP_KERNEL);
if (!filter)
goto fail_mem;
filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
if (!filter->filter_string)
goto fail_mem;
err = process_preds(file->event_call, filter_string, filter, pe);
if (err) {
filter_disable(file);
parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
append_filter_err(tr, pe, filter);
} else
event_set_filtered_flag(file);
filter_item = kzalloc(sizeof(*filter_item), GFP_KERNEL);
if (!filter_item)
goto fail_mem;
list_add_tail(&filter_item->list, &filter_list);
/*
* Regardless of if this returned an error, we still
* replace the filter for the call.
*/
filter_item->filter = event_filter(file);
event_set_filter(file, filter);
filter = NULL;
fail = false;
}
if (fail)
goto fail;
/*
* The calls can still be using the old filters.
* Do a synchronize_rcu() and to ensure all calls are
* done with them before we free them.
*/
tracepoint_synchronize_unregister();
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(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
return -EINVAL;
fail_mem:
__free_filter(filter);
/* If any call succeeded, we still need to sync */
if (!fail)
tracepoint_synchronize_unregister();
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_string, bool set_str,
struct filter_parse_error **pse,
struct event_filter **filterp)
{
struct event_filter *filter;
struct filter_parse_error *pe = NULL;
int err = 0;
if (WARN_ON_ONCE(*pse || *filterp))
return -EINVAL;
filter = kzalloc(sizeof(*filter), GFP_KERNEL);
if (filter && set_str) {
filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
if (!filter->filter_string)
err = -ENOMEM;
}
pe = kzalloc(sizeof(*pe), GFP_KERNEL);
if (!filter || !pe || err) {
kfree(pe);
__free_filter(filter);
return -ENOMEM;
}
/* we're committed to creating a new filter */
*filterp = filter;
*pse = pe;
return 0;
}
static void create_filter_finish(struct filter_parse_error *pe)
{
kfree(pe);
}
/**
* create_filter - create a filter for a trace_event_call
* @call: trace_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)
* Must be a pointer that references a NULL pointer.
*
* 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 trace_array *tr,
struct trace_event_call *call,
char *filter_string, bool set_str,
struct event_filter **filterp)
{
struct filter_parse_error *pe = NULL;
int err;
/* filterp must point to NULL */
if (WARN_ON(*filterp))
*filterp = NULL;
err = create_filter_start(filter_string, set_str, &pe, filterp);
if (err)
return err;
err = process_preds(call, filter_string, *filterp, pe);
if (err && set_str)
append_filter_err(tr, pe, *filterp);
create_filter_finish(pe);
return err;
}
int create_event_filter(struct trace_array *tr,
struct trace_event_call *call,
char *filter_str, bool set_str,
struct event_filter **filterp)
{
return create_filter(tr, 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 trace_subsystem_dir *dir,
struct trace_array *tr,
char *filter_str, struct event_filter **filterp)
{
struct filter_parse_error *pe = NULL;
int err;
err = create_filter_start(filter_str, true, &pe, filterp);
if (!err) {
err = process_system_preds(dir, tr, pe, filter_str);
if (!err) {
/* System filters just show a default message */
kfree((*filterp)->filter_string);
(*filterp)->filter_string = NULL;
} else {
append_filter_err(tr, pe, *filterp);
}
}
create_filter_finish(pe);
return err;
}
/* caller must hold event_mutex */
int apply_event_filter(struct trace_event_file *file, char *filter_string)
{
struct trace_event_call *call = file->event_call;
struct event_filter *filter = NULL;
int err;
if (file->flags & EVENT_FILE_FL_FREED)
return -ENODEV;
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 */
tracepoint_synchronize_unregister();
__free_filter(filter);
return 0;
}
err = create_filter(file->tr, 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 */
tracepoint_synchronize_unregister();
__free_filter(tmp);
}
}
return err;
}
int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
char *filter_string)
{
struct event_subsystem *system = dir->subsystem;
struct trace_array *tr = dir->tr;
struct event_filter *filter = NULL;
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 */
tracepoint_synchronize_unregister();
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_rcu().
*/
__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, **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.
*/
strreplace(str, ',', ' ');
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)
{
struct ftrace_event_field *field = pred->field;
/*
* Check the 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;
return 0;
}
static int ftrace_function_set_filter_pred(struct filter_pred *pred,
struct function_filter_data *data)
{
int ret;
/* Checking the node is valid for function trace. */
ret = ftrace_function_check_pred(pred);
if (ret)
return ret;
return __ftrace_function_set_filter(pred->op == OP_EQ,
pred->regex.pattern,
pred->regex.len,
data);
}
static bool is_or(struct prog_entry *prog, int i)
{
int target;
/*
* Only "||" is allowed for function events, thus,
* all true branches should jump to true, and any
* false branch should jump to false.
*/
target = prog[i].target + 1;
/* True and false have NULL preds (all prog entries should jump to one */
if (prog[target].pred)
return false;
/* prog[target].target is 1 for TRUE, 0 for FALSE */
return prog[i].when_to_branch == prog[target].target;
}
static int ftrace_function_set_filter(struct perf_event *event,
struct event_filter *filter)
{
struct prog_entry *prog = rcu_dereference_protected(filter->prog,
lockdep_is_held(&event_mutex));
struct function_filter_data data = {
.first_filter = 1,
.first_notrace = 1,
.ops = &event->ftrace_ops,
};
int i;
for (i = 0; prog[i].pred; i++) {
struct filter_pred *pred = prog[i].pred;
if (!is_or(prog, i))
return -EINVAL;
if (ftrace_function_set_filter_pred(pred, &data) < 0)
return -EINVAL;
}
return 0;
}
#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 = NULL;
struct trace_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(NULL, 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 trace_event_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 ARRAY_SIZE(test_filter_data)
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 void update_pred_fn(struct event_filter *filter, char *fields)
{
struct prog_entry *prog = rcu_dereference_protected(filter->prog,
lockdep_is_held(&event_mutex));
int i;
for (i = 0; prog[i].pred; i++) {
struct filter_pred *pred = prog[i].pred;
struct ftrace_event_field *field = pred->field;
WARN_ON_ONCE(!pred->fn);
if (!field) {
WARN_ONCE(1, "all leafs should have field defined %d", i);
continue;
}
if (!strchr(fields, *field->name))
continue;
pred->fn = test_pred_visited_fn;
}
}
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(NULL, &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;
}
/* Needed to dereference filter->prog */
mutex_lock(&event_mutex);
/*
* The preemption disabling is not really needed for self
* tests, but the rcu dereference will complain without it.
*/
preempt_disable();
if (*d->not_visited)
update_pred_fn(filter, d->not_visited);
test_pred_visited = 0;
err = filter_match_preds(filter, &d->rec);
preempt_enable();
mutex_unlock(&event_mutex);
__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 */
|