| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * trace_events_filter - generic event filtering |
| * |
| * 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" |
| |
| /* 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); |
| |
| /* 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; |
| } |
| |
| /* 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; |
| 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; |
| } |
| |
| 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 |
| 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; |
| } |
| |
| 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); |
| } |
| |
| 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 (!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 separately. |
| */ |
| 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 */ |