diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9de3e2a2f042..6fb46a06c9dc 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1216,12 +1216,11 @@ struct ftrace_event_field { int is_signed; }; +struct prog_entry; + struct event_filter { - int n_preds; /* Number assigned */ - int a_preds; /* allocated */ - struct filter_pred __rcu *preds; - struct filter_pred __rcu *root; - char *filter_string; + struct prog_entry __rcu *prog; + char *filter_string; }; struct event_subsystem { @@ -1413,12 +1412,8 @@ struct filter_pred { unsigned short *ops; struct ftrace_event_field *field; int offset; - int not; + int not; int op; - unsigned short index; - unsigned short parent; - unsigned short left; - unsigned short right; }; static inline bool is_string_field(struct ftrace_event_field *field) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 9d383f4383dc..703a416aa5c2 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -33,60 +33,52 @@ "# 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_OR, "||", 1 ), \ - C( OP_AND, "&&", 2 ), \ - C( OP_GLOB, "~", 4 ), \ - C( OP_NE, "!=", 4 ), \ - C( OP_EQ, "==", 4 ), \ - C( OP_LT, "<", 5 ), \ - C( OP_LE, "<=", 5 ), \ - C( OP_GT, ">", 5 ), \ - C( OP_GE, ">=", 5 ), \ - C( OP_BAND, "&", 6 ), \ - C( OP_NOT, "!", 6 ), \ - C( OP_NONE, "OP_NONE", 0 ), \ - C( OP_OPEN_PAREN, "(", 0 ), \ - C( OP_MAX, NULL, 0 ) + 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, c) a +#define C(a, b) a enum filter_op_ids { OPS }; -struct filter_op { - int id; - char *string; - int precedence; -}; - #undef C -#define C(a, b, c) { a, b, c } +#define C(a, b) b -static struct filter_op filter_ops[] = { OPS }; +static const char * ops[] = { OPS }; /* - * pred functions are OP_LT, OP_LE, OP_GT, OP_GE, and OP_BAND + * 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_LT +#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( UNBALANCED_PAREN, "Unbalanced parens"), \ - C( TOO_MANY_OPERANDS, "Too many operands"), \ - C( OPERAND_TOO_LONG, "Operand too long"), \ - C( FIELD_NOT_FOUND, "Field not found"), \ - C( ILLEGAL_FIELD_OP, "Illegal operation for field type"), \ - 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( MISSING_FIELD, "Missing field name and/or value"), \ - C( INVALID_FILTER, "Meaningless filter expression"), \ - C( IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \ - C( ILLEGAL_NOT_OP, "Illegal use of '!'"), + 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)?"), #undef C #define C(a, b) FILT_ERR_##a @@ -98,84 +90,535 @@ enum { ERRORS }; static char *err_text[] = { ERRORS }; -struct opstack_op { - enum filter_op_ids op; - struct list_head list; +/* 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; }; -struct postfix_elt { - enum filter_op_ids op; - char *operand; - struct list_head list; -}; +/** + * 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; -struct filter_parse_state { - struct filter_op *ops; - struct list_head opstack; - struct list_head postfix; + 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; - - struct { - char *string; - unsigned int cnt; - unsigned int tail; - } infix; - - struct { - char string[MAX_FILTER_STR_VAL]; - int pos; - unsigned int tail; - } operand; }; -struct pred_stack { - struct filter_pred **preds; - int index; +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, }; -/* If not of not match is equal to not of not, then it is a match */ +/* + * 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(sizeof(*op_stack) * nr_parens, GFP_KERNEL); + if (!op_stack) + return ERR_PTR(-ENOMEM); + prog_stack = kmalloc(sizeof(*prog_stack) * nr_preds, GFP_KERNEL); + if (!prog_stack) { + parse_error(pe, -ENOMEM, 0); + goto out_free; + } + inverts = kmalloc(sizeof(*inverts) * nr_preds, 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) + return ERR_PTR(-EINVAL); + *(++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 '|': + if (next[1] == next[0]) { + ptr++; + break; + } + 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; + } + + 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; + } + } + + return prog; +out_free: + kfree(op_stack); + kfree(prog_stack); + kfree(inverts); + 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; \ - int match = (*addr < val); \ - return !!match == !pred->not; \ + 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; \ - int match = (*addr <= val); \ - return !!match == !pred->not; \ + 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; \ - int match = (*addr > val); \ - return !!match == !pred->not; \ + 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; \ - int match = (*addr >= val); \ - return !!match == !pred->not; \ + 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; \ - int match = !!(*addr & val); \ - return match == !pred->not; \ + return !!(*addr & val); \ } \ static const filter_pred_fn_t pred_funcs_##type[] = { \ - filter_pred_LT_##type, \ filter_pred_LE_##type, \ - filter_pred_GT_##type, \ + filter_pred_LT_##type, \ filter_pred_GE_##type, \ + filter_pred_GT_##type, \ filter_pred_BAND_##type, \ }; @@ -261,44 +704,36 @@ static int filter_pred_strloc(struct filter_pred *pred, void *event) static int filter_pred_cpu(struct filter_pred *pred, void *event) { int cpu, cmp; - int match = 0; cpu = raw_smp_processor_id(); cmp = pred->val; switch (pred->op) { case OP_EQ: - match = cpu == cmp; - break; + return cpu == cmp; + case OP_NE: + return cpu != cmp; case OP_LT: - match = cpu < cmp; - break; + return cpu < cmp; case OP_LE: - match = cpu <= cmp; - break; + return cpu <= cmp; case OP_GT: - match = cpu > cmp; - break; + return cpu > cmp; case OP_GE: - match = cpu >= cmp; - break; + return cpu >= cmp; default: - break; + return 0; } - - return !!match == !pred->not; } /* Filter predicate for COMM. */ static int filter_pred_comm(struct filter_pred *pred, void *event) { - int cmp, match; + int cmp; cmp = pred->regex.match(current->comm, &pred->regex, - pred->regex.field_len); - match = cmp ^ pred->not; - - return match; + TASK_COMM_LEN); + return cmp ^ pred->not; } static int filter_pred_none(struct filter_pred *pred, void *event) @@ -355,6 +790,7 @@ static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused) return 1; return 0; } + /** * filter_parse_regex - parse a basic regex * @buff: the raw regex @@ -415,10 +851,9 @@ static void filter_build_regex(struct filter_pred *pred) struct regex *r = &pred->regex; char *search; enum regex_type type = MATCH_FULL; - int not = 0; if (pred->op == OP_GLOB) { - type = filter_parse_regex(r->pattern, r->len, &search, ¬); + type = filter_parse_regex(r->pattern, r->len, &search, &pred->not); r->len = strlen(search); memmove(r->pattern, search, r->len+1); } @@ -440,210 +875,32 @@ static void filter_build_regex(struct filter_pred *pred) r->match = regex_match_glob; break; } - - pred->not ^= not; -} - -enum move_type { - MOVE_DOWN, - MOVE_UP_FROM_LEFT, - MOVE_UP_FROM_RIGHT -}; - -static struct filter_pred * -get_pred_parent(struct filter_pred *pred, struct filter_pred *preds, - int index, enum move_type *move) -{ - if (pred->parent & FILTER_PRED_IS_RIGHT) - *move = MOVE_UP_FROM_RIGHT; - else - *move = MOVE_UP_FROM_LEFT; - pred = &preds[pred->parent & ~FILTER_PRED_IS_RIGHT]; - - return pred; -} - -enum walk_return { - WALK_PRED_ABORT, - WALK_PRED_PARENT, - WALK_PRED_DEFAULT, -}; - -typedef int (*filter_pred_walkcb_t) (enum move_type move, - struct filter_pred *pred, - int *err, void *data); - -static int walk_pred_tree(struct filter_pred *preds, - struct filter_pred *root, - filter_pred_walkcb_t cb, void *data) -{ - struct filter_pred *pred = root; - enum move_type move = MOVE_DOWN; - int done = 0; - - if (!preds) - return -EINVAL; - - do { - int err = 0, ret; - - ret = cb(move, pred, &err, data); - if (ret == WALK_PRED_ABORT) - return err; - if (ret == WALK_PRED_PARENT) - goto get_parent; - - switch (move) { - case MOVE_DOWN: - if (pred->left != FILTER_PRED_INVALID) { - pred = &preds[pred->left]; - continue; - } - goto get_parent; - case MOVE_UP_FROM_LEFT: - pred = &preds[pred->right]; - move = MOVE_DOWN; - continue; - case MOVE_UP_FROM_RIGHT: - get_parent: - if (pred == root) - break; - pred = get_pred_parent(pred, preds, - pred->parent, - &move); - continue; - } - done = 1; - } while (!done); - - /* We are fine. */ - return 0; -} - -/* - * A series of AND or ORs where found together. Instead of - * climbing up and down the tree branches, an array of the - * ops were made in order of checks. We can just move across - * the array and short circuit if needed. - */ -static int process_ops(struct filter_pred *preds, - struct filter_pred *op, void *rec) -{ - struct filter_pred *pred; - int match = 0; - int type; - int i; - - /* - * Micro-optimization: We set type to true if op - * is an OR and false otherwise (AND). Then we - * just need to test if the match is equal to - * the type, and if it is, we can short circuit the - * rest of the checks: - * - * if ((match && op->op == OP_OR) || - * (!match && op->op == OP_AND)) - * return match; - */ - type = op->op == OP_OR; - - for (i = 0; i < op->val; i++) { - pred = &preds[op->ops[i]]; - if (!WARN_ON_ONCE(!pred->fn)) - match = pred->fn(pred, rec); - if (!!match == type) - break; - } - /* If not of not match is equal to not of not, then it is a match */ - return !!match == !op->not; -} - -struct filter_match_preds_data { - struct filter_pred *preds; - int match; - void *rec; -}; - -static int filter_match_preds_cb(enum move_type move, struct filter_pred *pred, - int *err, void *data) -{ - struct filter_match_preds_data *d = data; - - *err = 0; - switch (move) { - case MOVE_DOWN: - /* only AND and OR have children */ - if (pred->left != FILTER_PRED_INVALID) { - /* If ops is set, then it was folded. */ - if (!pred->ops) - return WALK_PRED_DEFAULT; - /* We can treat folded ops as a leaf node */ - d->match = process_ops(d->preds, pred, d->rec); - } else { - if (!WARN_ON_ONCE(!pred->fn)) - d->match = pred->fn(pred, d->rec); - } - - return WALK_PRED_PARENT; - case MOVE_UP_FROM_LEFT: - /* - * Check for short circuits. - * - * Optimization: !!match == (pred->op == OP_OR) - * is the same as: - * if ((match && pred->op == OP_OR) || - * (!match && pred->op == OP_AND)) - */ - if (!!d->match == (pred->op == OP_OR)) - return WALK_PRED_PARENT; - break; - case MOVE_UP_FROM_RIGHT: - break; - } - - return WALK_PRED_DEFAULT; } /* return 1 if event matches, 0 otherwise (discard) */ int filter_match_preds(struct event_filter *filter, void *rec) { - struct filter_pred *preds; - struct filter_pred *root; - struct filter_match_preds_data data = { - /* match is currently meaningless */ - .match = -1, - .rec = rec, - }; - int n_preds, ret; + struct prog_entry *prog; + int i; /* no filter is considered a match */ if (!filter) return 1; - n_preds = filter->n_preds; - if (!n_preds) + prog = rcu_dereference_sched(filter->prog); + if (!prog) return 1; - /* - * n_preds, root and filter->preds are protect with preemption disabled. - */ - root = rcu_dereference_sched(filter->root); - if (!root) - return 1; - - data.preds = preds = rcu_dereference_sched(filter->preds); - ret = walk_pred_tree(preds, root, filter_match_preds_cb, &data); - WARN_ON(ret); - return data.match; + 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 parse_error(struct filter_parse_state *ps, int err, int pos) -{ - ps->lasterr = err; - ps->lasterr_pos = pos; -} - static void remove_filter_string(struct event_filter *filter) { if (!filter) @@ -653,11 +910,11 @@ static void remove_filter_string(struct event_filter *filter) filter->filter_string = NULL; } -static void append_filter_err(struct filter_parse_state *ps, +static void append_filter_err(struct filter_parse_error *pe, struct event_filter *filter) { struct trace_seq *s; - int pos = ps->lasterr_pos; + int pos = pe->lasterr_pos; char *buf; int len; @@ -671,11 +928,19 @@ static void append_filter_err(struct filter_parse_state *ps, len = strlen(filter->filter_string); if (pos > len) - len = pos; + pos = len; + + /* indexing is off by one */ + if (pos) + pos++; trace_seq_puts(s, filter->filter_string); - trace_seq_printf(s, "\n%*s", pos, "^"); - trace_seq_printf(s, "\nparse_error: %s\n", err_text[ps->lasterr]); + if (pe->lasterr > 0) { + trace_seq_printf(s, "\n%*s", pos, "^"); + trace_seq_printf(s, "\nparse_error: %s\n", err_text[pe->lasterr]); + } else { + trace_seq_printf(s, "\nError: (%d)\n", pe->lasterr); + } trace_seq_putc(s, 0); buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL); if (buf) { @@ -715,108 +980,18 @@ void print_subsystem_event_filter(struct event_subsystem *system, mutex_unlock(&event_mutex); } -static int __alloc_pred_stack(struct pred_stack *stack, int n_preds) -{ - stack->preds = kcalloc(n_preds + 1, sizeof(*stack->preds), GFP_KERNEL); - if (!stack->preds) - return -ENOMEM; - stack->index = n_preds; - return 0; -} - -static void __free_pred_stack(struct pred_stack *stack) -{ - kfree(stack->preds); - stack->index = 0; -} - -static int __push_pred_stack(struct pred_stack *stack, - struct filter_pred *pred) -{ - int index = stack->index; - - if (WARN_ON(index == 0)) - return -ENOSPC; - - stack->preds[--index] = pred; - stack->index = index; - return 0; -} - -static struct filter_pred * -__pop_pred_stack(struct pred_stack *stack) -{ - struct filter_pred *pred; - int index = stack->index; - - pred = stack->preds[index++]; - if (!pred) - return NULL; - - stack->index = index; - return pred; -} - -static int filter_set_pred(struct event_filter *filter, - int idx, - struct pred_stack *stack, - struct filter_pred *src) -{ - struct filter_pred *dest = &filter->preds[idx]; - struct filter_pred *left; - struct filter_pred *right; - - *dest = *src; - dest->index = idx; - - if (dest->op == OP_OR || dest->op == OP_AND) { - right = __pop_pred_stack(stack); - left = __pop_pred_stack(stack); - if (!left || !right) - return -EINVAL; - /* - * If both children can be folded - * and they are the same op as this op or a leaf, - * then this op can be folded. - */ - if (left->index & FILTER_PRED_FOLD && - ((left->op == dest->op && !left->not) || - left->left == FILTER_PRED_INVALID) && - right->index & FILTER_PRED_FOLD && - ((right->op == dest->op && !right->not) || - right->left == FILTER_PRED_INVALID)) - dest->index |= FILTER_PRED_FOLD; - - dest->left = left->index & ~FILTER_PRED_FOLD; - dest->right = right->index & ~FILTER_PRED_FOLD; - left->parent = dest->index & ~FILTER_PRED_FOLD; - right->parent = dest->index | FILTER_PRED_IS_RIGHT; - } else { - /* - * Make dest->left invalid to be used as a quick - * way to know this is a leaf node. - */ - dest->left = FILTER_PRED_INVALID; - - /* All leafs allow folding the parent ops. */ - dest->index |= FILTER_PRED_FOLD; - } - - return __push_pred_stack(stack, dest); -} - -static void __free_preds(struct event_filter *filter) +static void free_prog(struct event_filter *filter) { + struct prog_entry *prog; int i; - if (filter->preds) { - for (i = 0; i < filter->n_preds; i++) - kfree(filter->preds[i].ops); - kfree(filter->preds); - filter->preds = NULL; - } - filter->a_preds = 0; - filter->n_preds = 0; + 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) @@ -834,7 +1009,7 @@ static void __free_filter(struct event_filter *filter) if (!filter) return; - __free_preds(filter); + free_prog(filter); kfree(filter->filter_string); kfree(filter); } @@ -844,30 +1019,6 @@ void free_event_filter(struct event_filter *filter) __free_filter(filter); } -static int __alloc_preds(struct event_filter *filter, int n_preds) -{ - struct filter_pred *pred; - int i; - - if (filter->preds) - __free_preds(filter); - - filter->preds = kcalloc(n_preds, sizeof(*filter->preds), GFP_KERNEL); - - if (!filter->preds) - return -ENOMEM; - - filter->a_preds = n_preds; - filter->n_preds = 0; - - for (i = 0; i < n_preds; i++) { - pred = &filter->preds[i]; - pred->fn = filter_pred_none; - } - - return 0; -} - static inline void __remove_filter(struct trace_event_file *file) { filter_disable(file); @@ -904,27 +1055,6 @@ static void filter_free_subsystem_filters(struct trace_subsystem_dir *dir, } } -static int filter_add_pred(struct filter_parse_state *ps, - struct event_filter *filter, - struct filter_pred *pred, - struct pred_stack *stack) -{ - int err; - - if (WARN_ON(filter->n_preds == filter->a_preds)) { - parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0); - return -ENOSPC; - } - - err = filter_set_pred(filter, filter->n_preds, stack, pred); - if (err) - return err; - - filter->n_preds++; - - return 0; -} - int filter_assign_type(const char *type) { if (strstr(type, "__data_loc") && strstr(type, "char")) @@ -936,17 +1066,6 @@ int filter_assign_type(const char *type) return FILTER_OTHER; } -static bool is_legal_op(struct ftrace_event_field *field, enum filter_op_ids op) -{ - if (is_string_field(field) && - (op != OP_EQ && op != OP_NE && op != OP_GLOB)) - return false; - if (!is_string_field(field) && op == OP_GLOB) - return false; - - return true; -} - static filter_pred_fn_t select_comparison_fn(enum filter_op_ids op, int field_size, int field_is_signed) { @@ -1003,707 +1122,393 @@ static filter_pred_fn_t select_comparison_fn(enum filter_op_ids op, return fn; } -static int init_pred(struct filter_parse_state *ps, - struct ftrace_event_field *field, - struct filter_pred *pred) - +/* 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) { - filter_pred_fn_t fn = filter_pred_none; - unsigned long long val; + 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; - pred->offset = field->offset; + /* First find the field to associate to */ + while (isspace(str[i])) + i++; + s = i; - if (!is_legal_op(field, pred->op)) { - parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0); + 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; } - if (field->filter_type == FILTER_COMM) { - filter_build_regex(pred); - fn = filter_pred_comm; - pred->regex.field_len = TASK_COMM_LEN; - } else if (is_string_field(field)) { + 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; + /* Fall through */ + 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_STATIC_STRING) { - fn = filter_pred_string; + 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) - fn = filter_pred_strloc; + pred->fn = filter_pred_strloc; else - fn = filter_pred_pchar; - } else if (is_function_field(field)) { - if (strcmp(field->name, "ip")) { - parse_error(ps, FILT_ERR_IP_FIELD_ONLY, 0); - return -EINVAL; + pred->fn = filter_pred_pchar; + /* go past the last quote */ + i++; + + } else if (isdigit(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; } - } else { + + if (op == OP_GLOB) { + parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i); + goto err_free; + } + + /* 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(pred->regex.pattern, 0, &val); + ret = kstrtoll(num_buf, 0, &val); else - ret = kstrtoull(pred->regex.pattern, 0, &val); + ret = kstrtoull(num_buf, 0, &val); if (ret) { - parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0); - return -EINVAL; + parse_error(pe, FILT_ERR_ILLEGAL_INTVAL, pos + s); + goto err_free; } + pred->val = val; if (field->filter_type == FILTER_CPU) - fn = filter_pred_cpu; - else - fn = select_comparison_fn(pred->op, field->size, - field->is_signed); - if (!fn) { - parse_error(ps, FILT_ERR_INVALID_OP, 0); - return -EINVAL; + 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; } - if (pred->op == OP_NE) - pred->not ^= 1; + *pred_ptr = pred; + return i; - pred->fn = fn; - return 0; +err_free: + kfree(pred); + return -EINVAL; } -static void parse_init(struct filter_parse_state *ps, - struct filter_op *ops, - char *infix_string) -{ - memset(ps, '\0', sizeof(*ps)); - - ps->infix.string = infix_string; - ps->infix.cnt = strlen(infix_string); - ps->ops = ops; - - INIT_LIST_HEAD(&ps->opstack); - INIT_LIST_HEAD(&ps->postfix); -} - -static char infix_next(struct filter_parse_state *ps) -{ - if (!ps->infix.cnt) - return 0; - - ps->infix.cnt--; - - return ps->infix.string[ps->infix.tail++]; -} - -static char infix_peek(struct filter_parse_state *ps) -{ - if (ps->infix.tail == strlen(ps->infix.string)) - return 0; - - return ps->infix.string[ps->infix.tail]; -} - -static void infix_advance(struct filter_parse_state *ps) -{ - if (!ps->infix.cnt) - return; - - ps->infix.cnt--; - ps->infix.tail++; -} - -static inline int is_precedence_lower(struct filter_parse_state *ps, - int a, int b) -{ - return ps->ops[a].precedence < ps->ops[b].precedence; -} - -static inline int is_op_char(struct filter_parse_state *ps, char c) +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; - for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) { - if (ps->ops[i].string[0] == c) - return 1; - } + *err = 0; - return 0; -} - -static int infix_get_op(struct filter_parse_state *ps, char firstc) -{ - char nextc = infix_peek(ps); - char opstr[3]; - int i; - - opstr[0] = firstc; - opstr[1] = nextc; - opstr[2] = '\0'; - - for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) { - if (!strcmp(opstr, ps->ops[i].string)) { - infix_advance(ps); - return ps->ops[i].id; - } - } - - opstr[1] = '\0'; - - for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) { - if (!strcmp(opstr, ps->ops[i].string)) - return ps->ops[i].id; - } - - return OP_NONE; -} - -static inline void clear_operand_string(struct filter_parse_state *ps) -{ - memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL); - ps->operand.tail = 0; -} - -static inline int append_operand_char(struct filter_parse_state *ps, char c) -{ - if (ps->operand.tail == MAX_FILTER_STR_VAL - 1) - return -EINVAL; - - ps->operand.string[ps->operand.tail++] = c; - - return 0; -} - -static int filter_opstack_push(struct filter_parse_state *ps, - enum filter_op_ids op) -{ - struct opstack_op *opstack_op; - - opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL); - if (!opstack_op) - return -ENOMEM; - - opstack_op->op = op; - list_add(&opstack_op->list, &ps->opstack); - - return 0; -} - -static int filter_opstack_empty(struct filter_parse_state *ps) -{ - return list_empty(&ps->opstack); -} - -static int filter_opstack_top(struct filter_parse_state *ps) -{ - struct opstack_op *opstack_op; - - if (filter_opstack_empty(ps)) - return OP_NONE; - - opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list); - - return opstack_op->op; -} - -static int filter_opstack_pop(struct filter_parse_state *ps) -{ - struct opstack_op *opstack_op; - enum filter_op_ids op; - - if (filter_opstack_empty(ps)) - return OP_NONE; - - opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list); - op = opstack_op->op; - list_del(&opstack_op->list); - - kfree(opstack_op); - - return op; -} - -static void filter_opstack_clear(struct filter_parse_state *ps) -{ - while (!filter_opstack_empty(ps)) - filter_opstack_pop(ps); -} - -static char *curr_operand(struct filter_parse_state *ps) -{ - return ps->operand.string; -} - -static int postfix_append_operand(struct filter_parse_state *ps, char *operand) -{ - struct postfix_elt *elt; - - elt = kmalloc(sizeof(*elt), GFP_KERNEL); - if (!elt) - return -ENOMEM; - - elt->op = OP_NONE; - elt->operand = kstrdup(operand, GFP_KERNEL); - if (!elt->operand) { - kfree(elt); - return -ENOMEM; - } - - list_add_tail(&elt->list, &ps->postfix); - - return 0; -} - -static int postfix_append_op(struct filter_parse_state *ps, enum filter_op_ids op) -{ - struct postfix_elt *elt; - - elt = kmalloc(sizeof(*elt), GFP_KERNEL); - if (!elt) - return -ENOMEM; - - elt->op = op; - elt->operand = NULL; - - list_add_tail(&elt->list, &ps->postfix); - - return 0; -} - -static void postfix_clear(struct filter_parse_state *ps) -{ - struct postfix_elt *elt; - - while (!list_empty(&ps->postfix)) { - elt = list_first_entry(&ps->postfix, struct postfix_elt, list); - list_del(&elt->list); - kfree(elt->operand); - kfree(elt); - } -} - -static int filter_parse(struct filter_parse_state *ps) -{ - enum filter_op_ids op, top_op; - int in_string = 0; - char ch; - - while ((ch = infix_next(ps))) { - if (ch == '"') { - in_string ^= 1; + for (i = 0; str[i]; i++) { + if (isspace(str[i])) + continue; + if (quote) { + if (str[i] == quote) + quote = 0; continue; } - if (in_string) - goto parse_operand; - - if (isspace(ch)) + 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; - - if (is_op_char(ps, ch)) { - op = infix_get_op(ps, ch); - if (op == OP_NONE) { - parse_error(ps, FILT_ERR_INVALID_OP, 0); - return -EINVAL; + 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 (strlen(curr_operand(ps))) { - postfix_append_operand(ps, curr_operand(ps)); - clear_operand_string(ps); + 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; } - - while (!filter_opstack_empty(ps)) { - top_op = filter_opstack_top(ps); - if (!is_precedence_lower(ps, top_op, op)) { - top_op = filter_opstack_pop(ps); - postfix_append_op(ps, top_op); - continue; + switch (str[i]) { + case '(': + if (level == open) { + *err = i; + return TOO_MANY_OPEN; } + level--; + break; + case ')': + level++; + break; + case '\'': + case '"': + quote = str[i]; break; } - - filter_opstack_push(ps, op); - continue; - } - - if (ch == '(') { - filter_opstack_push(ps, OP_OPEN_PAREN); - continue; - } - - if (ch == ')') { - if (strlen(curr_operand(ps))) { - postfix_append_operand(ps, curr_operand(ps)); - clear_operand_string(ps); - } - - top_op = filter_opstack_pop(ps); - while (top_op != OP_NONE) { - if (top_op == OP_OPEN_PAREN) - break; - postfix_append_op(ps, top_op); - top_op = filter_opstack_pop(ps); - } - if (top_op == OP_NONE) { - parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0); - return -EINVAL; - } - continue; - } -parse_operand: - if (append_operand_char(ps, ch)) { - parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0); - return -EINVAL; } + /* First character is the '(' with missing ')' */ + *err = 0; + return TOO_MANY_OPEN; } - if (strlen(curr_operand(ps))) - postfix_append_operand(ps, curr_operand(ps)); - - while (!filter_opstack_empty(ps)) { - top_op = filter_opstack_pop(ps); - if (top_op == OP_NONE) - break; - if (top_op == OP_OPEN_PAREN) { - parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0); - return -EINVAL; - } - postfix_append_op(ps, top_op); - } - + /* Set the size of the required stacks */ + *parens = max_open; + *preds = nr_preds; return 0; } -static struct filter_pred *create_pred(struct filter_parse_state *ps, - struct trace_event_call *call, - enum filter_op_ids op, - char *operand1, char *operand2) -{ - struct ftrace_event_field *field; - static struct filter_pred pred; - - memset(&pred, 0, sizeof(pred)); - pred.op = op; - - if (op == OP_AND || op == OP_OR) - return &pred; - - if (!operand1 || !operand2) { - parse_error(ps, FILT_ERR_MISSING_FIELD, 0); - return NULL; - } - - field = trace_find_event_field(call, operand1); - if (!field) { - parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0); - return NULL; - } - - strcpy(pred.regex.pattern, operand2); - pred.regex.len = strlen(pred.regex.pattern); - pred.field = field; - return init_pred(ps, field, &pred) ? NULL : &pred; -} - -static int check_preds(struct filter_parse_state *ps) -{ - int n_normal_preds = 0, n_logical_preds = 0; - struct postfix_elt *elt; - int cnt = 0; - - list_for_each_entry(elt, &ps->postfix, list) { - if (elt->op == OP_NONE) { - cnt++; - continue; - } - - if (elt->op == OP_AND || elt->op == OP_OR) { - n_logical_preds++; - cnt--; - continue; - } - if (elt->op != OP_NOT) - cnt--; - n_normal_preds++; - /* all ops should have operands */ - if (cnt < 0) - break; - } - - if (cnt != 1 || !n_normal_preds || n_logical_preds >= n_normal_preds) { - parse_error(ps, FILT_ERR_INVALID_FILTER, 0); - return -EINVAL; - } - - return 0; -} - -static int count_preds(struct filter_parse_state *ps) -{ - struct postfix_elt *elt; - int n_preds = 0; - - list_for_each_entry(elt, &ps->postfix, list) { - if (elt->op == OP_NONE) - continue; - n_preds++; - } - - return n_preds; -} - -struct check_pred_data { - int count; - int max; -}; - -static int check_pred_tree_cb(enum move_type move, struct filter_pred *pred, - int *err, void *data) -{ - struct check_pred_data *d = data; - - if (WARN_ON(d->count++ > d->max)) { - *err = -EINVAL; - return WALK_PRED_ABORT; - } - return WALK_PRED_DEFAULT; -} - -/* - * The tree is walked at filtering of an event. If the tree is not correctly - * built, it may cause an infinite loop. Check here that the tree does - * indeed terminate. - */ -static int check_pred_tree(struct event_filter *filter, - struct filter_pred *root) -{ - struct check_pred_data data = { - /* - * The max that we can hit a node is three times. - * Once going down, once coming up from left, and - * once coming up from right. This is more than enough - * since leafs are only hit a single time. - */ - .max = 3 * filter->n_preds, - .count = 0, - }; - - return walk_pred_tree(filter->preds, root, - check_pred_tree_cb, &data); -} - -static int count_leafs_cb(enum move_type move, struct filter_pred *pred, - int *err, void *data) -{ - int *count = data; - - if ((move == MOVE_DOWN) && - (pred->left == FILTER_PRED_INVALID)) - (*count)++; - - return WALK_PRED_DEFAULT; -} - -static int count_leafs(struct filter_pred *preds, struct filter_pred *root) -{ - int count = 0, ret; - - ret = walk_pred_tree(preds, root, count_leafs_cb, &count); - WARN_ON(ret); - return count; -} - -struct fold_pred_data { - struct filter_pred *root; - int count; - int children; -}; - -static int fold_pred_cb(enum move_type move, struct filter_pred *pred, - int *err, void *data) -{ - struct fold_pred_data *d = data; - struct filter_pred *root = d->root; - - if (move != MOVE_DOWN) - return WALK_PRED_DEFAULT; - if (pred->left != FILTER_PRED_INVALID) - return WALK_PRED_DEFAULT; - - if (WARN_ON(d->count == d->children)) { - *err = -EINVAL; - return WALK_PRED_ABORT; - } - - pred->index &= ~FILTER_PRED_FOLD; - root->ops[d->count++] = pred->index; - return WALK_PRED_DEFAULT; -} - -static int fold_pred(struct filter_pred *preds, struct filter_pred *root) -{ - struct fold_pred_data data = { - .root = root, - .count = 0, - }; - int children; - - /* No need to keep the fold flag */ - root->index &= ~FILTER_PRED_FOLD; - - /* If the root is a leaf then do nothing */ - if (root->left == FILTER_PRED_INVALID) - return 0; - - /* count the children */ - children = count_leafs(preds, &preds[root->left]); - children += count_leafs(preds, &preds[root->right]); - - root->ops = kcalloc(children, sizeof(*root->ops), GFP_KERNEL); - if (!root->ops) - return -ENOMEM; - - root->val = children; - data.children = children; - return walk_pred_tree(preds, root, fold_pred_cb, &data); -} - -static int fold_pred_tree_cb(enum move_type move, struct filter_pred *pred, - int *err, void *data) -{ - struct filter_pred *preds = data; - - if (move != MOVE_DOWN) - return WALK_PRED_DEFAULT; - if (!(pred->index & FILTER_PRED_FOLD)) - return WALK_PRED_DEFAULT; - - *err = fold_pred(preds, pred); - if (*err) - return WALK_PRED_ABORT; - - /* eveyrhing below is folded, continue with parent */ - return WALK_PRED_PARENT; -} - -/* - * To optimize the processing of the ops, if we have several "ors" or - * "ands" together, we can put them in an array and process them all - * together speeding up the filter logic. - */ -static int fold_pred_tree(struct event_filter *filter, - struct filter_pred *root) -{ - return walk_pred_tree(filter->preds, root, fold_pred_tree_cb, - filter->preds); -} - -static int replace_preds(struct trace_event_call *call, +static int process_preds(struct trace_event_call *call, + const char *filter_string, struct event_filter *filter, - struct filter_parse_state *ps, - bool dry_run) + struct filter_parse_error *pe) { - char *operand1 = NULL, *operand2 = NULL; - struct filter_pred *pred; - struct filter_pred *root; - struct postfix_elt *elt; - struct pred_stack stack = { }; /* init to NULL */ - int err; - int n_preds = 0; + struct prog_entry *prog; + int nr_parens; + int nr_preds; + int index; + int ret; - n_preds = count_preds(ps); - if (n_preds >= MAX_FILTER_PRED) { - parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0); - return -ENOSPC; + 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; } - err = check_preds(ps); - if (err) - return err; - - if (!dry_run) { - err = __alloc_pred_stack(&stack, n_preds); - if (err) - return err; - err = __alloc_preds(filter, n_preds); - if (err) - goto fail; + if (!nr_preds) { + prog = NULL; + } else { + prog = predicate_parse(filter_string, nr_parens, nr_preds, + parse_pred, call, pe); + if (IS_ERR(prog)) + return PTR_ERR(prog); } - - n_preds = 0; - list_for_each_entry(elt, &ps->postfix, list) { - if (elt->op == OP_NONE) { - if (!operand1) - operand1 = elt->operand; - else if (!operand2) - operand2 = elt->operand; - else { - parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0); - err = -EINVAL; - goto fail; - } - continue; - } - - if (elt->op == OP_NOT) { - if (!n_preds || operand1 || operand2) { - parse_error(ps, FILT_ERR_ILLEGAL_NOT_OP, 0); - err = -EINVAL; - goto fail; - } - if (!dry_run) - filter->preds[n_preds - 1].not ^= 1; - continue; - } - - if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) { - parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0); - err = -ENOSPC; - goto fail; - } - - pred = create_pred(ps, call, elt->op, operand1, operand2); - if (!pred) { - err = -EINVAL; - goto fail; - } - - if (!dry_run) { - err = filter_add_pred(ps, filter, pred, &stack); - if (err) - goto fail; - } - - operand1 = operand2 = NULL; - } - - if (!dry_run) { - /* We should have one item left on the stack */ - pred = __pop_pred_stack(&stack); - if (!pred) - return -EINVAL; - /* This item is where we start from in matching */ - root = pred; - /* Make sure the stack is empty */ - pred = __pop_pred_stack(&stack); - if (WARN_ON(pred)) { - err = -EINVAL; - filter->root = NULL; - goto fail; - } - err = check_pred_tree(filter, root); - if (err) - goto fail; - - /* Optimize the tree */ - err = fold_pred_tree(filter, root); - if (err) - goto fail; - - /* We don't set root until we know it works */ - barrier(); - filter->root = root; - } - - err = 0; -fail: - __free_pred_stack(&stack); - return err; + rcu_assign_pointer(filter->prog, prog); + return 0; } static inline void event_set_filtered_flag(struct trace_event_file *file) @@ -1753,9 +1558,9 @@ struct filter_list { struct event_filter *filter; }; -static int replace_system_preds(struct trace_subsystem_dir *dir, +static int process_system_preds(struct trace_subsystem_dir *dir, struct trace_array *tr, - struct filter_parse_state *ps, + struct filter_parse_error *pe, char *filter_string) { struct trace_event_file *file; @@ -1766,29 +1571,11 @@ static int replace_system_preds(struct trace_subsystem_dir *dir, bool fail = true; int err; - list_for_each_entry(file, &tr->events, list) { - if (file->system != dir) - continue; - - /* - * Try to see if the filter can be applied - * (filter arg is ignored on dry_run) - */ - err = replace_preds(file->event_call, NULL, ps, true); - if (err) - event_set_no_set_filter_flag(file); - else - event_clear_no_set_filter_flag(file); - } - list_for_each_entry(file, &tr->events, list) { if (file->system != dir) continue; - if (event_no_set_filter_flag(file)) - continue; - filter = kzalloc(sizeof(*filter), GFP_KERNEL); if (!filter) goto fail_mem; @@ -1797,11 +1584,11 @@ static int replace_system_preds(struct trace_subsystem_dir *dir, if (!filter->filter_string) goto fail_mem; - err = replace_preds(file->event_call, filter, ps, false); + err = process_preds(file->event_call, filter_string, filter, pe); if (err) { filter_disable(file); - parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0); - append_filter_err(ps, filter); + parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0); + append_filter_err(pe, filter); } else event_set_filtered_flag(file); @@ -1843,7 +1630,7 @@ static int replace_system_preds(struct trace_subsystem_dir *dir, list_del(&filter_item->list); kfree(filter_item); } - parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0); + parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0); return -EINVAL; fail_mem: kfree(filter); @@ -1859,16 +1646,16 @@ static int replace_system_preds(struct trace_subsystem_dir *dir, } static int create_filter_start(char *filter_string, bool set_str, - struct filter_parse_state **psp, + struct filter_parse_error **pse, struct event_filter **filterp) { struct event_filter *filter; - struct filter_parse_state *ps = NULL; + struct filter_parse_error *pe = NULL; int err = 0; - WARN_ON_ONCE(*psp || *filterp); + if (WARN_ON_ONCE(*pse || *filterp)) + return -EINVAL; - /* allocate everything, and if any fails, free all and fail */ filter = kzalloc(sizeof(*filter), GFP_KERNEL); if (filter && set_str) { filter->filter_string = kstrdup(filter_string, GFP_KERNEL); @@ -1876,32 +1663,24 @@ static int create_filter_start(char *filter_string, bool set_str, err = -ENOMEM; } - ps = kzalloc(sizeof(*ps), GFP_KERNEL); + pe = kzalloc(sizeof(*pe), GFP_KERNEL); - if (!filter || !ps || err) { - kfree(ps); + if (!filter || !pe || err) { + kfree(pe); __free_filter(filter); return -ENOMEM; } /* we're committed to creating a new filter */ *filterp = filter; - *psp = ps; + *pse = pe; - parse_init(ps, filter_ops, filter_string); - err = filter_parse(ps); - if (err && set_str) - append_filter_err(ps, filter); - return err; + return 0; } -static void create_filter_finish(struct filter_parse_state *ps) +static void create_filter_finish(struct filter_parse_error *pe) { - if (ps) { - filter_opstack_clear(ps); - postfix_clear(ps); - kfree(ps); - } + kfree(pe); } /** @@ -1921,24 +1700,20 @@ static void create_filter_finish(struct filter_parse_state *ps) * freeing it. */ static int create_filter(struct trace_event_call *call, - char *filter_str, bool set_str, + char *filter_string, bool set_str, struct event_filter **filterp) { + struct filter_parse_error *pe = NULL; struct event_filter *filter = NULL; - struct filter_parse_state *ps = NULL; int err; - err = create_filter_start(filter_str, set_str, &ps, &filter); - if (!err) { - err = replace_preds(call, filter, ps, false); - if (err && set_str) - append_filter_err(ps, filter); - } - if (err && !set_str) { - free_event_filter(filter); - filter = NULL; - } - create_filter_finish(ps); + err = create_filter_start(filter_string, set_str, &pe, &filter); + if (err) + return err; + + err = process_preds(call, filter_string, filter, pe); + if (err && set_str) + append_filter_err(pe, filter); *filterp = filter; return err; @@ -1965,21 +1740,21 @@ static int create_system_filter(struct trace_subsystem_dir *dir, char *filter_str, struct event_filter **filterp) { struct event_filter *filter = NULL; - struct filter_parse_state *ps = NULL; + struct filter_parse_error *pe = NULL; int err; - err = create_filter_start(filter_str, true, &ps, &filter); + err = create_filter_start(filter_str, true, &pe, &filter); if (!err) { - err = replace_system_preds(dir, tr, ps, filter_str); + err = process_system_preds(dir, tr, pe, filter_str); if (!err) { /* System filters just show a default message */ kfree(filter->filter_string); filter->filter_string = NULL; } else { - append_filter_err(ps, filter); + append_filter_err(pe, filter); } } - create_filter_finish(ps); + create_filter_finish(pe); *filterp = filter; return err; @@ -2162,66 +1937,79 @@ static int __ftrace_function_set_filter(int filter, char *buf, int len, return ret; } -static int ftrace_function_check_pred(struct filter_pred *pred, int leaf) +static int ftrace_function_check_pred(struct filter_pred *pred) { struct ftrace_event_field *field = pred->field; - if (leaf) { - /* - * Check the leaf predicate for function trace, verify: - * - only '==' and '!=' is used - * - the 'ip' field is used - */ - if ((pred->op != OP_EQ) && (pred->op != OP_NE)) - return -EINVAL; + /* + * 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; - } else { - /* - * Check the non leaf predicate for function trace, verify: - * - only '||' is used - */ - if (pred->op != OP_OR) - return -EINVAL; - } + if (strcmp(field->name, "ip")) + return -EINVAL; return 0; } -static int ftrace_function_set_filter_cb(enum move_type move, - struct filter_pred *pred, - int *err, void *data) +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. */ - if ((move != MOVE_DOWN) || - (pred->left != FILTER_PRED_INVALID)) { - *err = ftrace_function_check_pred(pred, 0); - } else { - *err = ftrace_function_check_pred(pred, 1); - if (*err) - return WALK_PRED_ABORT; + ret = ftrace_function_check_pred(pred); + if (ret) + return ret; - *err = __ftrace_function_set_filter(pred->op == OP_EQ, - pred->regex.pattern, - pred->regex.len, - data); - } + return __ftrace_function_set_filter(pred->op == OP_EQ, + pred->regex.pattern, + pred->regex.len, + data); +} - return (*err) ? WALK_PRED_ABORT : WALK_PRED_DEFAULT; +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 = filter->prog; struct function_filter_data data = { .first_filter = 1, .first_notrace = 1, .ops = &event->ftrace_ops, }; + int i; - return walk_pred_tree(filter->preds, filter->root, - ftrace_function_set_filter_cb, &data); + 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, @@ -2364,26 +2152,27 @@ static int test_pred_visited_fn(struct filter_pred *pred, void *event) return 1; } -static int test_walk_pred_cb(enum move_type move, struct filter_pred *pred, - int *err, void *data) +static void update_pred_fn(struct event_filter *filter, char *fields) { - char *fields = data; + struct prog_entry *prog = filter->prog; + int i; - if ((move == MOVE_DOWN) && - (pred->left == FILTER_PRED_INVALID)) { + for (i = 0; prog[i].pred; i++) { + struct filter_pred *pred = prog[i].pred; struct ftrace_event_field *field = pred->field; - if (!field) { - WARN(1, "all leafs should have field defined"); - return WALK_PRED_DEFAULT; - } - if (!strchr(fields, *field->name)) - return WALK_PRED_DEFAULT; + WARN_ON_ONCE(!pred->fn); + + if (!field) { + WARN_ONCE(1, "all leafs should have field defined %d", i); + continue; + } + + if (!strchr(fields, *field->name)) + continue; - WARN_ON(!pred->fn); pred->fn = test_pred_visited_fn; } - return WALK_PRED_DEFAULT; } static __init int ftrace_test_event_filter(void) @@ -2413,9 +2202,7 @@ static __init int ftrace_test_event_filter(void) */ preempt_disable(); if (*d->not_visited) - walk_pred_tree(filter->preds, filter->root, - test_walk_pred_cb, - d->not_visited); + update_pred_fn(filter, d->not_visited); test_pred_visited = 0; err = filter_match_preds(filter, &d->rec);