C(TOO_MANY_SORT_FIELDS, "Too many sort fields (Max = 2)"), \
C(INVALID_SORT_FIELD, "Sort field must be a key or a val"), \
C(INVALID_STR_OPERAND, "String type can not be an operand in expression"), \
- C(EXPECT_NUMBER, "Expecting numeric literal"),
+ C(EXPECT_NUMBER, "Expecting numeric literal"), \
+ C(UNARY_MINUS_SUBEXPR, "Unary minus not supported in sub-expressions"), \
+ C(SYM_OFFSET_SUBEXPR, ".sym-offset not supported in sub-expressions"),
#undef C
#define C(a, b) HIST_ERR_##a
return expr;
}
-static int contains_operator(char *str)
+/*
+ * If field_op != FIELD_OP_NONE, *sep points to the root operator
+ * of the expression tree to be evaluated.
+ */
+static int contains_operator(char *str, char **sep)
{
enum field_op_id field_op = FIELD_OP_NONE;
- char *op;
+ char *minus_op, *plus_op, *div_op, *mult_op;
+
+
+ /*
+ * Report the last occurrence of the operators first, so that the
+ * expression is evaluated left to right. This is important since
+ * subtraction and division are not associative.
+ *
+ * e.g
+ * 64/8/4/2 is 1, i.e 64/8/4/2 = ((64/8)/4)/2
+ * 14-7-5-2 is 0, i.e 14-7-5-2 = ((14-7)-5)-2
+ */
- op = strpbrk(str, "+-/*");
- if (!op)
- return FIELD_OP_NONE;
+ /*
+ * First, find lower precedence addition and subtraction
+ * since the expression will be evaluated recursively.
+ */
+ minus_op = strrchr(str, '-');
+ if (minus_op) {
+ /* Unfortunately, the modifier ".sym-offset" can confuse things. */
+ if (minus_op - str >= 4 && !strncmp(minus_op - 4, ".sym-offset", 11))
+ goto out;
- switch (*op) {
- case '-':
/*
- * Unfortunately, the modifier ".sym-offset"
- * can confuse things.
+ * Unary minus is not supported in sub-expressions. If
+ * present, it is always the next root operator.
*/
- if (op - str >= 4 && !strncmp(op - 4, ".sym-offset", 11))
- return FIELD_OP_NONE;
-
- if (*str == '-')
+ if (minus_op == str) {
field_op = FIELD_OP_UNARY_MINUS;
- else
- field_op = FIELD_OP_MINUS;
- break;
- case '+':
- field_op = FIELD_OP_PLUS;
- break;
- case '/':
+ goto out;
+ }
+
+ field_op = FIELD_OP_MINUS;
+ }
+
+ plus_op = strrchr(str, '+');
+ if (plus_op || minus_op) {
+ /*
+ * For operators of the same precedence use to rightmost as the
+ * root, so that the expression is evaluated left to right.
+ */
+ if (plus_op > minus_op)
+ field_op = FIELD_OP_PLUS;
+ goto out;
+ }
+
+ /*
+ * Multiplication and division have higher precedence than addition and
+ * subtraction.
+ */
+ div_op = strrchr(str, '/');
+ if (div_op)
field_op = FIELD_OP_DIV;
- break;
- case '*':
+
+ mult_op = strrchr(str, '*');
+ /*
+ * For operators of the same precedence use to rightmost as the
+ * root, so that the expression is evaluated left to right.
+ */
+ if (mult_op > div_op)
field_op = FIELD_OP_MULT;
- break;
- default:
- break;
+
+out:
+ if (sep) {
+ switch (field_op) {
+ case FIELD_OP_UNARY_MINUS:
+ case FIELD_OP_MINUS:
+ *sep = minus_op;
+ break;
+ case FIELD_OP_PLUS:
+ *sep = plus_op;
+ break;
+ case FIELD_OP_DIV:
+ *sep = div_op;
+ break;
+ case FIELD_OP_MULT:
+ *sep = mult_op;
+ break;
+ case FIELD_OP_NONE:
+ default:
+ *sep = NULL;
+ break;
+ }
}
return field_op;
if (strcmp(var_name, name) == 0) {
field = hist_data->attrs->var_defs.expr[i];
- if (contains_operator(field) || is_var_ref(field))
+ if (contains_operator(field, NULL) || is_var_ref(field))
continue;
return field;
}
static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
char *str, unsigned long flags,
- char *var_name, unsigned int level);
+ char *var_name, unsigned int *n_subexprs);
static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
char *str, unsigned long flags,
- char *var_name, unsigned int level)
+ char *var_name, unsigned int *n_subexprs)
{
struct hist_field *operand1, *expr = NULL;
unsigned long operand_flags;
int ret = 0;
char *s;
+ /* Unary minus operator, increment n_subexprs */
+ ++*n_subexprs;
+
/* we support only -(xxx) i.e. explicit parens required */
- if (level > 3) {
+ if (*n_subexprs > 3) {
hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
ret = -EINVAL;
goto free;
}
s = strrchr(str, ')');
- if (s)
+ if (s) {
+ /* unary minus not supported in sub-expressions */
+ if (*(s+1) != '\0') {
+ hist_err(file->tr, HIST_ERR_UNARY_MINUS_SUBEXPR,
+ errpos(str));
+ ret = -EINVAL;
+ goto free;
+ }
*s = '\0';
+ }
else {
ret = -EINVAL; /* no closing ')' */
goto free;
}
operand_flags = 0;
- operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
+ operand1 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
if (IS_ERR(operand1)) {
ret = PTR_ERR(operand1);
goto free;
static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
char *str, unsigned long flags,
- char *var_name, unsigned int level)
+ char *var_name, unsigned int *n_subexprs)
{
struct hist_field *operand1 = NULL, *operand2 = NULL, *expr = NULL;
unsigned long operand_flags;
int field_op, ret = -EINVAL;
char *sep, *operand1_str;
- if (level > 3) {
+ if (*n_subexprs > 3) {
hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
return ERR_PTR(-EINVAL);
}
- field_op = contains_operator(str);
+ /*
+ * ".sym-offset" in expressions has no effect on their evaluation,
+ * but can confuse operator parsing.
+ */
+ if (*n_subexprs == 0) {
+ sep = strstr(str, ".sym-offset");
+ if (sep) {
+ *sep = '\0';
+ if (strpbrk(str, "+-/*") || strpbrk(sep + 11, "+-/*")) {
+ *sep = '.';
+ hist_err(file->tr, HIST_ERR_SYM_OFFSET_SUBEXPR,
+ errpos(sep));
+ return ERR_PTR(-EINVAL);
+ }
+ *sep = '.';
+ }
+ }
+
+ field_op = contains_operator(str, &sep);
if (field_op == FIELD_OP_NONE)
return parse_atom(hist_data, file, str, &flags, var_name);
if (field_op == FIELD_OP_UNARY_MINUS)
- return parse_unary(hist_data, file, str, flags, var_name, ++level);
+ return parse_unary(hist_data, file, str, flags, var_name, n_subexprs);
- switch (field_op) {
- case FIELD_OP_MINUS:
- sep = "-";
- break;
- case FIELD_OP_PLUS:
- sep = "+";
- break;
- case FIELD_OP_DIV:
- sep = "/";
- break;
- case FIELD_OP_MULT:
- sep = "*";
- break;
- default:
- goto free;
- }
+ /* Binary operator found, increment n_subexprs */
+ ++*n_subexprs;
- /*
- * Multiplication and division are only supported in single operator
- * expressions, since the expression is always evaluated from right
- * to left.
- */
- if ((field_op == FIELD_OP_DIV || field_op == FIELD_OP_MULT) && level > 0) {
- hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str));
- return ERR_PTR(-EINVAL);
- }
+ /* Split the expression string at the root operator */
+ if (!sep)
+ goto free;
+ *sep = '\0';
+ operand1_str = str;
+ str = sep+1;
- operand1_str = strsep(&str, sep);
if (!operand1_str || !str)
goto free;
operand_flags = 0;
- operand1 = parse_atom(hist_data, file, operand1_str,
- &operand_flags, NULL);
+
+ /* LHS of string is an expression e.g. a+b in a+b+c */
+ operand1 = parse_expr(hist_data, file, operand1_str, operand_flags, NULL, n_subexprs);
if (IS_ERR(operand1)) {
ret = PTR_ERR(operand1);
operand1 = NULL;
goto free;
}
- /* rest of string could be another expression e.g. b+c in a+b+c */
+ /* RHS of string is another expression e.g. c in a+b+c */
operand_flags = 0;
- operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, ++level);
+ operand2 = parse_expr(hist_data, file, str, operand_flags, NULL, n_subexprs);
if (IS_ERR(operand2)) {
ret = PTR_ERR(operand2);
operand2 = NULL;
unsigned long flags)
{
struct hist_field *hist_field;
- int ret = 0;
+ int ret = 0, n_subexprs = 0;
- hist_field = parse_expr(hist_data, file, field_str, flags, var_name, 0);
+ hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs);
if (IS_ERR(hist_field)) {
ret = PTR_ERR(hist_field);
goto out;
struct hist_field *hist_field = NULL;
unsigned long flags = 0;
unsigned int key_size;
- int ret = 0;
+ int ret = 0, n_subexprs = 0;
if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
return -EINVAL;
hist_field = create_hist_field(hist_data, NULL, flags, NULL);
} else {
hist_field = parse_expr(hist_data, file, field_str, flags,
- NULL, 0);
+ NULL, &n_subexprs);
if (IS_ERR(hist_field)) {
ret = PTR_ERR(hist_field);
goto out;
projects / platform / kernel / linux-rpi.git / commitdiff