Adding upstream version 1.6.4.upstream/1.6.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1653 insertions, 0 deletions

diff --git a/src/tracefs-sqlhist.c b/src/tracefs-sqlhist.c
new file mode 100644
index 0000000..3f571b7
--- /dev/null
+++ b/src/tracefs-sqlhist.c
@@ -0,0 +1,1653 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
+ *
+ * Updates:
+ * Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+#include <trace-seq.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "tracefs.h"
+#include "tracefs-local.h"
+#include "sqlhist-parse.h"
+
+extern int yylex_init(void* ptr_yy_globals);
+extern int yylex_init_extra(struct sqlhist_bison *sb, void* ptr_yy_globals);
+extern int yylex_destroy (void * yyscanner );
+
+struct str_hash {
+	struct str_hash		*next;
+	char			*str;
+};
+
+enum alias_type {
+	ALIAS_EVENT,
+	ALIAS_FIELD,
+};
+
+enum field_type {
+	FIELD_NONE,
+	FIELD_FROM,
+	FIELD_TO,
+};
+
+#define for_each_field(expr, field, table) \
+	for (expr = (table)->fields; expr; expr = (field)->next)
+
+struct field {
+	struct expr		*next;	/* private link list */
+	const char		*system;
+	const char		*event_name;
+	struct tep_event	*event;
+	const char		*raw;
+	const char		*label;
+	const char		*field;
+	const char		*type;
+	enum field_type		ftype;
+};
+
+struct filter {
+	enum filter_type	type;
+	struct expr		*lval;
+	struct expr		*rval;
+};
+
+struct match {
+	struct match		*next;
+	struct expr		*lval;
+	struct expr		*rval;
+};
+
+struct compare {
+	enum compare_type	type;
+	struct expr		*lval;
+	struct expr		*rval;
+	const char		*name;
+};
+
+enum expr_type
+{
+	EXPR_NUMBER,
+	EXPR_STRING,
+	EXPR_FIELD,
+	EXPR_FILTER,
+	EXPR_COMPARE,
+};
+
+struct expr {
+	struct expr		*free_list;
+	struct expr		*next;
+	enum expr_type		type;
+	int			line;
+	int			idx;
+	union {
+		struct field	field;
+		struct filter	filter;
+		struct compare	compare;
+		const char	*string;
+		long		number;
+	};
+};
+
+struct sql_table {
+	struct sqlhist_bison	*sb;
+	const char		*name;
+	struct expr		*exprs;
+	struct expr		*fields;
+	struct expr		*from;
+	struct expr		*to;
+	struct expr		*where;
+	struct expr		**next_where;
+	struct match		*matches;
+	struct match		**next_match;
+	struct expr		*selections;
+	struct expr		**next_selection;
+};
+
+__hidden int my_yyinput(void *extra, char *buf, int max)
+{
+	struct sqlhist_bison *sb = extra;
+
+	if (!sb || !sb->buffer)
+		return -1;
+
+	if (sb->buffer_idx + max > sb->buffer_size)
+		max = sb->buffer_size - sb->buffer_idx;
+
+	if (max)
+		memcpy(buf, sb->buffer + sb->buffer_idx, max);
+
+	sb->buffer_idx += max;
+
+	return max;
+}
+
+__hidden void sql_parse_error(struct sqlhist_bison *sb, const char *text,
+			      const char *fmt, va_list ap)
+{
+	const char *buffer = sb->buffer;
+	struct trace_seq s;
+	int line = sb->line_no;
+	int idx = sb->line_idx - strlen(text);
+	int i;
+
+	if (!buffer)
+		return;
+
+	trace_seq_init(&s);
+	if (!s.buffer) {
+		tracefs_warning("Error allocating internal buffer\n");
+		return;
+	}
+
+	for (i = 0; line && buffer[i]; i++) {
+		if (buffer[i] == '\n')
+			line--;
+	}
+	for (; buffer[i] && buffer[i] != '\n'; i++)
+		trace_seq_putc(&s, buffer[i]);
+	trace_seq_putc(&s, '\n');
+	for (i = idx; i > 0; i--)
+		trace_seq_putc(&s, ' ');
+	trace_seq_puts(&s, "^\n");
+	trace_seq_printf(&s, "ERROR: '%s'\n", text);
+	trace_seq_vprintf(&s, fmt, ap);
+
+	trace_seq_terminate(&s);
+
+	sb->parse_error_str = strdup(s.buffer);
+	trace_seq_destroy(&s);
+}
+
+static void parse_error(struct sqlhist_bison *sb, const char *text,
+			const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	sql_parse_error(sb, text, fmt, ap);
+	va_end(ap);
+}
+
+__hidden unsigned int quick_hash(const char *str)
+{
+	unsigned int val = 0;
+	int len = strlen(str);
+
+	for (; len >= 4; str += 4, len -= 4) {
+		val += str[0];
+		val += str[1] << 8;
+		val += str[2] << 16;
+		val += str[3] << 24;
+	}
+	for (; len > 0; str++, len--)
+		val += str[0] << (len * 8);
+
+        val *= 2654435761;
+
+        return val & ((1 << HASH_BITS) - 1);
+}
+
+
+static struct str_hash *find_string(struct sqlhist_bison *sb, const char *str)
+{
+	unsigned int key = quick_hash(str);
+	struct str_hash *hash = sb->str_hash[key];
+
+	for (; hash; hash = hash->next) {
+		if (!strcmp(hash->str, str))
+			return hash;
+	}
+	return NULL;
+}
+
+/*
+ * If @str is found, then return the hash string.
+ * This lets store_str() know to free str.
+ */
+static char **add_hash(struct sqlhist_bison *sb, const char *str)
+{
+	struct str_hash *hash;
+	unsigned int key;
+
+	if ((hash = find_string(sb, str))) {
+		return &hash->str;
+	}
+
+	hash = malloc(sizeof(*hash));
+	if (!hash)
+		return NULL;
+	key = quick_hash(str);
+	hash->next = sb->str_hash[key];
+	sb->str_hash[key] = hash;
+	hash->str = NULL;
+	return &hash->str;
+}
+
+__hidden char *store_str(struct sqlhist_bison *sb, const char *str)
+{
+	char **pstr = add_hash(sb, str);
+
+	if (!pstr)
+		return NULL;
+
+	if (!(*pstr))
+		*pstr = strdup(str);
+
+	return *pstr;
+}
+
+__hidden void *add_cast(struct sqlhist_bison *sb,
+			void *data, const char *type)
+{
+	struct expr *expr = data;
+	struct field *field = &expr->field;
+
+	field->type = type;
+	return expr;
+}
+
+__hidden int add_selection(struct sqlhist_bison *sb, void *select,
+			   const char *name)
+{
+	struct sql_table *table = sb->table;
+	struct expr *expr = select;
+
+	switch (expr->type) {
+	case EXPR_FIELD:
+		expr->field.label = name;
+		break;
+	case EXPR_COMPARE:
+		expr->compare.name = name;
+		break;
+	case EXPR_NUMBER:
+	case EXPR_STRING:
+	case EXPR_FILTER:
+	default:
+		return -1;
+	}
+
+	if (expr->next)
+		return -1;
+
+	*table->next_selection = expr;
+	table->next_selection = &expr->next;
+
+	return 0;
+}
+
+static struct expr *find_field(struct sqlhist_bison *sb,
+				const char *raw, const char *label)
+{
+	struct field *field;
+	struct expr *expr;
+
+	for_each_field(expr, field, sb->table) {
+		field = &expr->field;
+
+		if (!strcmp(field->raw, raw)) {
+			if (label && !field->label)
+				field->label = label;
+			if (label && strcmp(label, field->label) != 0)
+				continue;
+			return expr;
+		}
+
+		if (label && !strcmp(field->raw, label)) {
+			if (!field->label) {
+				field->label = label;
+				field->raw = raw;
+			}
+			return expr;
+		}
+
+		if (!field->label)
+			continue;
+
+		if (!strcmp(field->label, raw))
+			return expr;
+
+		if (label && !strcmp(field->label, label))
+			return expr;
+	}
+	return NULL;
+}
+
+static void *create_expr(struct sqlhist_bison *sb,
+			 enum expr_type type, struct expr **expr_p)
+{
+	struct expr *expr;
+
+	expr = calloc(1, sizeof(*expr));
+	if (!expr)
+		return NULL;
+
+	if (expr_p)
+		*expr_p = expr;
+
+	expr->free_list = sb->table->exprs;
+	sb->table->exprs = expr;
+
+	expr->type = type;
+	expr->line = sb->line_no;
+	expr->idx = sb->line_idx;
+
+	switch (type) {
+	case EXPR_FIELD:	return &expr->field;
+	case EXPR_COMPARE:	return &expr->compare;
+	case EXPR_NUMBER:	return &expr->number;
+	case EXPR_STRING:	return &expr->string;
+	case EXPR_FILTER:	return &expr->filter;
+	}
+
+	return NULL;
+}
+
+#define __create_expr(var, type, ENUM, expr)			\
+	do {							\
+		var = (type *)create_expr(sb, EXPR_##ENUM, expr);	\
+	} while(0)
+
+#define create_field(var, expr)				\
+	__create_expr(var, struct field, FIELD, expr)
+
+#define create_filter(var, expr)			\
+	__create_expr(var, struct filter, FILTER, expr)
+
+#define create_compare(var, expr)				\
+	__create_expr(var, struct compare, COMPARE, expr)
+
+#define create_string(var, expr)			\
+	__create_expr(var, const char *, STRING, expr)
+
+#define create_number(var, expr)			\
+	__create_expr(var, long, NUMBER, expr)
+
+__hidden void *add_field(struct sqlhist_bison *sb,
+			 const char *field_name, const char *label)
+{
+	struct sql_table *table = sb->table;
+	struct expr *expr;
+	struct field *field;
+
+	expr = find_field(sb, field_name, label);
+	if (expr)
+		return expr;
+
+	create_field(field, &expr);
+
+	field->next = table->fields;
+	table->fields = expr;
+
+	field->raw = field_name;
+	field->label = label;
+
+	return expr;
+}
+
+__hidden void *add_filter(struct sqlhist_bison *sb,
+			  void *A, void *B, enum filter_type op)
+{
+	struct filter *filter;
+	struct expr *expr;
+
+	create_filter(filter, &expr);
+
+	filter->lval = A;
+	filter->rval = B;
+
+	filter->type = op;
+
+	return expr;
+}
+
+__hidden int add_match(struct sqlhist_bison *sb, void *A, void *B)
+{
+	struct sql_table *table = sb->table;
+	struct match *match;
+
+	match = calloc(1, sizeof(*match));
+	if (!match)
+		return -1;
+
+	match->lval = A;
+	match->rval = B;
+
+	*table->next_match = match;
+	table->next_match = &match->next;
+
+	return 0;
+}
+__hidden void *add_compare(struct sqlhist_bison *sb,
+			   void *A, void *B, enum compare_type type)
+{
+	struct compare *compare;
+	struct expr *expr;
+
+	create_compare(compare, &expr);
+
+	compare = &expr->compare;
+	compare->lval = A;
+	compare->rval = B;
+	compare->type = type;
+
+	return expr;
+}
+
+__hidden int add_where(struct sqlhist_bison *sb, void *item)
+{
+	struct expr *expr = item;
+	struct sql_table *table = sb->table;
+
+	if (expr->type != EXPR_FILTER)
+		return -1;
+
+	*table->next_where = expr;
+	table->next_where = &expr->next;
+
+	if (expr->next)
+		return -1;
+
+	return 0;
+}
+
+__hidden int add_from(struct sqlhist_bison *sb, void *item)
+{
+	struct expr *expr = item;
+
+	if (expr->type != EXPR_FIELD)
+		return -1;
+
+	sb->table->from = expr;
+
+	return 0;
+}
+
+__hidden int add_to(struct sqlhist_bison *sb, void *item)
+{
+	struct expr *expr = item;
+
+	if (expr->type != EXPR_FIELD)
+		return -1;
+
+	sb->table->to = expr;
+
+	return 0;
+}
+
+__hidden void *add_string(struct sqlhist_bison *sb, const char *str)
+{
+	struct expr *expr;
+	const char **str_p;
+
+	create_string(str_p, &expr);
+	*str_p = str;
+	return expr;
+}
+
+__hidden void *add_number(struct sqlhist_bison *sb, long val)
+{
+	struct expr *expr;
+	long *num;
+
+	create_number(num, &expr);
+	*num = val;
+	return expr;
+}
+
+__hidden int table_start(struct sqlhist_bison *sb)
+{
+	struct sql_table *table;
+
+	table = calloc(1, sizeof(*table));
+	if (!table)
+		return -ENOMEM;
+
+	table->sb = sb;
+	sb->table = table;
+
+	table->next_where = &table->where;
+	table->next_match = &table->matches;
+	table->next_selection = &table->selections;
+
+	return 0;
+}
+
+static int test_event_exists(struct tep_handle *tep,
+			     struct sqlhist_bison *sb,
+			     struct expr *expr, struct tep_event **pevent)
+{
+	struct field *field = &expr->field;
+	const char *system = field->system;
+	const char *event = field->event_name;
+
+	if (!field->event)
+		field->event = tep_find_event_by_name(tep, system, event);
+	if (pevent)
+		*pevent = field->event;
+
+	if (field->event)
+		return 0;
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, field->raw, "event not found\n");
+	return -1;
+}
+
+static int test_field_exists(struct tep_handle *tep,
+			     struct sqlhist_bison *sb,
+			     struct expr *expr)
+{
+	struct field *field = &expr->field;
+	struct tep_format_field *tfield;
+	char *field_name;
+	const char *p;
+
+	if (!field->event) {
+		if (test_event_exists(tep, sb, expr, NULL))
+			return -1;
+	}
+
+	/* The field could have a conversion */
+	p = strchr(field->field, '.');
+	if (p)
+		field_name = strndup(field->field, p - field->field);
+	else
+		field_name = strdup(field->field);
+
+	if (!field_name)
+		return -1;
+
+	if (!strcmp(field_name, TRACEFS_TIMESTAMP) ||
+	    !strcmp(field->field, TRACEFS_TIMESTAMP_USECS))
+		tfield = (void *)1L;
+	else
+		tfield = tep_find_any_field(field->event, field_name);
+	free(field_name);
+
+	if (!tfield && (!strcmp(field->field, "COMM") || !strcmp(field->field, "comm")))
+		tfield = (void *)1L;
+
+	if (tfield)
+		return 0;
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, field->raw,
+		    "Field '%s' not part of event %s\n",
+		    field->field, field->event_name);
+	return -1;
+}
+
+static int update_vars(struct tep_handle *tep,
+		       struct sql_table *table,
+		       struct expr *expr)
+{
+	struct sqlhist_bison *sb = table->sb;
+	struct field *event_field = &expr->field;
+	enum field_type ftype = FIELD_NONE;
+	struct tep_event *event;
+	struct field *field;
+	const char *label;
+	const char *raw = event_field->raw;
+	const char *event_name;
+	const char *system;
+	const char *p;
+	int label_len = 0, event_len, system_len;
+
+	if (expr == table->to)
+		ftype = FIELD_TO;
+	else if (expr == table->from)
+		ftype = FIELD_FROM;
+
+	p = strchr(raw, '.');
+	if (p) {
+		char *str;
+
+		str = strndup(raw, p - raw);
+		if (!str)
+			return -1;
+		event_field->system = store_str(sb, str);
+		free(str);
+		if (!event_field->system)
+			return -1;
+		p++;
+	} else {
+		p = raw;
+	}
+
+	event_field->event_name = store_str(sb, p);
+	if (!event_field->event_name)
+		return -1;
+
+	if (test_event_exists(tep, sb, expr, &event))
+		return -1;
+
+	if (!event_field->system)
+		event_field->system = store_str(sb, event->system);
+
+	if (!event_field->system)
+		return -1;
+
+	label = event_field->label;
+	if (label)
+		label_len = strlen(label);
+
+	system = event_field->system;
+	system_len = strlen(system);
+
+	event_name = event_field->event_name;
+	event_len = strlen(event_name);
+
+	for_each_field(expr, field, table) {
+		int len;
+
+		field = &expr->field;
+
+		if (field->event)
+			continue;
+
+		raw = field->raw;
+
+		/*
+		 * The field could be:
+		 *     system.event.field...
+		 *     event.field...
+		 *     label.field...
+		 * We check label first.
+		 */
+
+		len = label_len;
+		if (label && !strncmp(raw, label, len) &&
+		    raw[len] == '.') {
+			/* Label matches and takes precedence */
+			goto found;
+		}
+
+		if (!strncmp(raw, system, system_len) &&
+		    raw[system_len] == '.') {
+			raw += system_len + 1;
+			/* Check the event portion next */
+		}
+
+		len = event_len;
+		if (strncmp(raw, event_name, len) ||
+		    raw[len] != '.') {
+			/* Does not match */
+			continue;
+		}
+ found:
+		field->system = system;
+		field->event_name = event_name;
+		field->event = event;
+		field->field = raw + len + 1;
+		field->ftype = ftype;
+
+		if (!strcmp(field->field, "TIMESTAMP"))
+			field->field = store_str(sb, TRACEFS_TIMESTAMP);
+		if (!strcmp(field->field, "TIMESTAMP_USECS"))
+			field->field = store_str(sb, TRACEFS_TIMESTAMP_USECS);
+		if (test_field_exists(tep, sb, expr))
+			return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Called when there's a FROM but no JOIN(to), which means that the
+ * selections can be fields and not mention the event itself.
+ */
+static int update_fields(struct tep_handle *tep,
+			 struct sql_table *table,
+			 struct expr *expr)
+{
+	struct field *event_field = &expr->field;
+	struct sqlhist_bison *sb = table->sb;
+	struct tep_format_field *tfield;
+	struct tep_event *event;
+	struct field *field;
+	const char *p;
+	int len;
+
+	/* First update fields with aliases an such and add event */
+	update_vars(tep, table, expr);
+
+	/*
+	 * If event is not found, the creation of the synth will
+	 * add a proper error, so return "success".
+	*/
+	if (!event_field->event)
+		return 0;
+
+	event = event_field->event;
+
+	for_each_field(expr, field, table) {
+		const char *field_name;
+
+		field = &expr->field;
+
+		if (field->event)
+			continue;
+
+		field_name = field->raw;
+
+		p = strchr(field_name, '.');
+		if (p) {
+			len = p - field_name;
+			p = strndup(field_name, len);
+			if (!p)
+				return -1;
+			field_name = store_str(sb, p);
+			if (!field_name)
+				return -1;
+			free((char *)p);
+		}
+
+		tfield = tep_find_any_field(event, field_name);
+		/* Let it error properly later */
+		if (!tfield)
+			continue;
+
+		field->system = event_field->system;
+		field->event_name = event_field->event_name;
+		field->event = event;
+		field->field = field_name;
+	}
+
+	return 0;
+}
+
+static int match_error(struct sqlhist_bison *sb, struct match *match,
+		       struct field *lmatch, struct field *rmatch)
+{
+	struct field *lval = &match->lval->field;
+	struct field *rval = &match->rval->field;
+	struct field *field;
+	struct expr *expr;
+
+	if (lval->system != lmatch->system ||
+	    lval->event != lmatch->event) {
+		expr = match->lval;
+		field = lval;
+	} else {
+		expr = match->rval;
+		field = rval;
+	}
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, field->raw,
+		    "'%s' and '%s' must be a field for each event: '%s' and '%s'\n",
+		    lval->raw, rval->raw, sb->table->to->field.raw,
+		    sb->table->from->field.raw);
+
+	return -1;
+}
+
+static int test_match(struct sql_table *table, struct match *match)
+{
+	struct field *lval, *rval;
+	struct field *to, *from;
+
+	if (!match->lval || !match->rval)
+		return -1;
+
+	if (match->lval->type != EXPR_FIELD || match->rval->type != EXPR_FIELD)
+		return -1;
+
+	to = &table->to->field;
+	from = &table->from->field;
+
+	lval = &match->lval->field;
+	rval = &match->rval->field;
+
+	/*
+	 * Note, strings are stored in the string store, so all
+	 * duplicate strings are the same value, and we can use
+	 * normal "==" and "!=" instead of strcmp().
+	 *
+	 * Either lval == to and rval == from
+	 * or lval == from and rval == to.
+	 */
+	if ((lval->system != to->system) ||
+	    (lval->event != to->event)) {
+		if ((rval->system != to->system) ||
+		    (rval->event != to->event) ||
+		    (lval->system != from->system) ||
+		    (lval->event != from->event))
+			return match_error(table->sb, match, from, to);
+	} else {
+		if ((rval->system != from->system) ||
+		    (rval->event != from->event) ||
+		    (lval->system != to->system) ||
+		    (lval->event != to->event))
+			return match_error(table->sb, match, to, from);
+	}
+	return 0;
+}
+
+static void assign_match(const char *system, const char *event,
+			 struct match *match,
+			 const char **start_match, const char **end_match)
+{
+	struct field *lval, *rval;
+
+	lval = &match->lval->field;
+	rval = &match->rval->field;
+
+	if (lval->system == system &&
+	    lval->event_name == event) {
+		*start_match = lval->field;
+		*end_match = rval->field;
+	} else {
+		*start_match = rval->field;
+		*end_match = lval->field;
+	}
+}
+
+static int build_compare(struct tracefs_synth *synth,
+			 const char *system, const char *event,
+			 struct compare *compare)
+{
+	const char *start_field;
+	const char *end_field;
+	struct field *lval, *rval;
+	enum tracefs_synth_calc calc;
+	int ret;
+
+	if (!compare->name)
+		return -1;
+
+	lval = &compare->lval->field;
+	rval = &compare->rval->field;
+
+	if (lval->system == system &&
+	    lval->event_name == event) {
+		start_field = lval->field;
+		end_field = rval->field;
+		calc = TRACEFS_SYNTH_DELTA_START;
+	} else {
+		start_field = rval->field;
+		end_field = lval->field;
+		calc = TRACEFS_SYNTH_DELTA_END;
+	}
+
+	if (compare->type == COMPARE_ADD)
+		calc = TRACEFS_SYNTH_ADD;
+
+	ret = tracefs_synth_add_compare_field(synth, start_field,
+					      end_field, calc,
+					      compare->name);
+	return ret;
+}
+
+static int verify_filter_error(struct sqlhist_bison *sb, struct expr *expr,
+			       const char *event)
+{
+	struct field *field = &expr->field;
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, field->raw,
+		    "event '%s' can not be grouped or '||' together with '%s'\n"
+		    "All filters between '&&' must be for the same event\n",
+		    field->event, event);
+	return -1;
+}
+
+static int do_verify_filter(struct sqlhist_bison *sb, struct filter *filter,
+			    const char **system, const char **event,
+			    enum field_type *ftype)
+{
+	int ret;
+
+	if (filter->type == FILTER_OR ||
+	    filter->type == FILTER_AND) {
+		ret = do_verify_filter(sb, &filter->lval->filter, system, event, ftype);
+		if (ret)
+			return ret;
+		return do_verify_filter(sb, &filter->rval->filter, system, event, ftype);
+	}
+	if (filter->type == FILTER_GROUP ||
+	    filter->type == FILTER_NOT_GROUP) {
+		return do_verify_filter(sb, &filter->lval->filter, system, event, ftype);
+	}
+
+	/*
+	 * system and event will be NULL until we find the left most
+	 * node. Then assign it, and compare on the way back up.
+	 */
+	if (!*system && !*event) {
+		*system = filter->lval->field.system;
+		*event = filter->lval->field.event_name;
+		*ftype = filter->lval->field.ftype;
+		return 0;
+	}
+
+	if (filter->lval->field.system != *system ||
+	    filter->lval->field.event_name != *event)
+		return verify_filter_error(sb, filter->lval, *event);
+
+	return 0;
+}
+
+static int verify_filter(struct sqlhist_bison *sb, struct filter *filter,
+			 const char **system, const char **event,
+			 enum field_type *ftype)
+{
+	int ret;
+
+	switch (filter->type) {
+	case FILTER_OR:
+	case FILTER_AND:
+	case FILTER_GROUP:
+	case FILTER_NOT_GROUP:
+		break;
+	default:
+		return do_verify_filter(sb, filter, system, event, ftype);
+	}
+
+	ret = do_verify_filter(sb, &filter->lval->filter, system, event, ftype);
+	if (ret)
+		return ret;
+
+	switch (filter->type) {
+	case FILTER_OR:
+	case FILTER_AND:
+		return do_verify_filter(sb, &filter->rval->filter, system, event, ftype);
+	default:
+		return 0;
+	}
+}
+
+static int test_field_exists(struct tep_handle *tep, struct sqlhist_bison *sb,
+			     struct expr *expr);
+
+static void filter_compare_error(struct tep_handle *tep,
+				 struct sqlhist_bison *sb,
+				 struct expr *expr)
+{
+	struct field *field = &expr->field;
+
+	switch (errno) {
+	case ENODEV:
+	case EBADE:
+		break;
+	case EINVAL:
+		parse_error(sb, field->raw, "Invalid compare\n");
+		break;
+	default:
+		parse_error(sb, field->raw, "System error?\n");
+		return;
+	}
+
+	/* ENODEV means that an event or field does not exist */
+	if (errno == ENODEV) {
+		if (test_field_exists(tep, sb, expr))
+			return;
+		if (test_field_exists(tep, sb, expr))
+			return;
+		return;
+	}
+
+	/* fields exist, but values are not compatible */
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, field->raw,
+		    "Field '%s' is not compatible to be compared with the given value\n",
+		    field->field);
+}
+
+static void filter_error(struct tep_handle *tep,
+			 struct sqlhist_bison *sb, struct expr *expr)
+{
+	struct filter *filter = &expr->filter;
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	switch (filter->type) {
+	case FILTER_NOT_GROUP:
+	case FILTER_GROUP:
+	case FILTER_OR:
+	case FILTER_AND:
+		break;
+	default:
+		filter_compare_error(tep, sb, filter->lval);
+		return;
+	}
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	parse_error(sb, "", "Problem with filter entry?\n");
+}
+
+static int build_filter(struct tep_handle *tep, struct sqlhist_bison *sb,
+			struct tracefs_synth *synth,
+			bool start, struct expr *expr, bool *started)
+{
+	int (*append_filter)(struct tracefs_synth *synth,
+			     enum tracefs_filter type,
+			     const char *field,
+			     enum tracefs_compare compare,
+			     const char *val);
+	struct filter *filter = &expr->filter;
+	enum tracefs_compare cmp;
+	const char *val;
+	int and_or = TRACEFS_FILTER_AND;
+	char num[64];
+	int ret;
+
+	if (start)
+		append_filter = tracefs_synth_append_start_filter;
+	else
+		append_filter = tracefs_synth_append_end_filter;
+
+	if (started && *started) {
+		ret = append_filter(synth, and_or, NULL, 0, NULL);
+		ret = append_filter(synth, TRACEFS_FILTER_OPEN_PAREN,
+				    NULL, 0, NULL);
+	}
+
+	switch (filter->type) {
+	case FILTER_NOT_GROUP:
+		ret = append_filter(synth, TRACEFS_FILTER_NOT,
+				    NULL, 0, NULL);
+		if (ret < 0)
+			goto out;
+		/* Fall through */
+	case FILTER_GROUP:
+		ret = append_filter(synth, TRACEFS_FILTER_OPEN_PAREN,
+				    NULL, 0, NULL);
+		if (ret < 0)
+			goto out;
+		ret = build_filter(tep, sb, synth, start, filter->lval, NULL);
+		if (ret < 0)
+			goto out;
+		ret = append_filter(synth, TRACEFS_FILTER_CLOSE_PAREN,
+				    NULL, 0, NULL);
+		goto out;
+
+	case FILTER_OR:
+		and_or = TRACEFS_FILTER_OR;
+		/* Fall through */
+	case FILTER_AND:
+		ret = build_filter(tep, sb, synth, start, filter->lval, NULL);
+		if (ret < 0)
+			goto out;
+		ret = append_filter(synth, and_or, NULL, 0, NULL);
+
+		if (ret)
+			goto out;
+		ret = build_filter(tep, sb, synth, start, filter->rval, NULL);
+		goto out;
+	default:
+		break;
+	}
+
+	switch (filter->rval->type) {
+	case EXPR_NUMBER:
+		sprintf(num, "%ld", filter->rval->number);
+		val = num;
+		break;
+	case EXPR_STRING:
+		val = filter->rval->string;
+		break;
+	default:
+		break;
+	}
+
+	switch (filter->type) {
+	case FILTER_EQ:		cmp = TRACEFS_COMPARE_EQ; break;
+	case FILTER_NE:		cmp = TRACEFS_COMPARE_NE; break;
+	case FILTER_LE:		cmp = TRACEFS_COMPARE_LE; break;
+	case FILTER_LT:		cmp = TRACEFS_COMPARE_LT; break;
+	case FILTER_GE:		cmp = TRACEFS_COMPARE_GE; break;
+	case FILTER_GT:		cmp = TRACEFS_COMPARE_GT; break;
+	case FILTER_BIN_AND:	cmp = TRACEFS_COMPARE_AND; break;
+	case FILTER_STR_CMP:	cmp = TRACEFS_COMPARE_RE; break;
+	default:
+		tracefs_warning("Error invalid filter type '%d'", filter->type);
+		return ERANGE;
+	}
+
+	ret = append_filter(synth, TRACEFS_FILTER_COMPARE,
+			    filter->lval->field.field, cmp, val);
+
+	if (ret)
+		filter_error(tep, sb, expr);
+ out:
+	if (!ret && started) {
+		if (*started)
+			ret = append_filter(synth, TRACEFS_FILTER_CLOSE_PAREN,
+					    NULL, 0, NULL);
+		*started = true;
+	}
+	return ret;
+}
+
+static void *field_match_error(struct tep_handle *tep, struct sqlhist_bison *sb,
+			       struct match *match)
+{
+	switch (errno) {
+	case ENODEV:
+	case EBADE:
+		break;
+	default:
+		/* System error */
+		return NULL;
+	}
+
+	/* ENODEV means that an event or field does not exist */
+	if (errno == ENODEV) {
+		if (test_field_exists(tep, sb, match->lval))
+			return NULL;
+		if (test_field_exists(tep, sb, match->rval))
+			return NULL;
+		return NULL;
+	}
+
+	/* fields exist, but values are not compatible */
+	sb->line_no = match->lval->line;
+	sb->line_idx = match->lval->idx;
+
+	parse_error(sb, match->lval->field.raw,
+		    "Field '%s' is not compatible to match field '%s'\n",
+		    match->lval->field.raw, match->rval->field.raw);
+	return NULL;
+}
+
+static void *synth_init_error(struct tep_handle *tep, struct sql_table *table)
+{
+	struct sqlhist_bison *sb = table->sb;
+	struct match *match = table->matches;
+
+	switch (errno) {
+	case ENODEV:
+	case EBADE:
+		break;
+	default:
+		/* System error */
+		return NULL;
+	}
+
+	/* ENODEV could mean that start or end events do not exist */
+	if (errno == ENODEV) {
+		if (test_event_exists(tep, sb, table->from, NULL))
+			return NULL;
+		if (test_event_exists(tep, sb, table->to, NULL))
+			return NULL;
+	}
+
+	return field_match_error(tep, sb, match);
+}
+
+static void selection_error(struct tep_handle *tep,
+			    struct sqlhist_bison *sb, struct expr *expr)
+{
+	/* We just care about event not existing */
+	if (errno != ENODEV)
+		return;
+
+	test_field_exists(tep, sb, expr);
+}
+
+static void compare_error(struct tep_handle *tep,
+			    struct sqlhist_bison *sb, struct expr *expr)
+{
+	struct compare *compare = &expr->compare;
+
+	if (!compare->name) {
+		sb->line_no = expr->line;
+		sb->line_idx = expr->idx + strlen("no name");
+
+		parse_error(sb, "no name",
+		    "Field calculations must be labeled 'AS name'\n");
+	}
+
+	switch (errno) {
+	case ENODEV:
+	case EBADE:
+		break;
+	default:
+		/* System error */
+		return;
+	}
+
+	/* ENODEV means that an event or field does not exist */
+	if (errno == ENODEV) {
+		if (test_field_exists(tep, sb, compare->lval))
+			return;
+		if (test_field_exists(tep, sb, compare->rval))
+			return;
+		return;
+	}
+
+	/* fields exist, but values are not compatible */
+	sb->line_no = compare->lval->line;
+	sb->line_idx = compare->lval->idx;
+
+	parse_error(sb, compare->lval->field.raw,
+		    "'%s' is not compatible to compare with '%s'\n",
+		    compare->lval->field.raw, compare->rval->field.raw);
+}
+
+static void compare_no_to_error(struct sqlhist_bison *sb, struct expr *expr)
+{
+	struct compare *compare = &expr->compare;
+
+	sb->line_no = compare->lval->line;
+	sb->line_idx = compare->lval->idx;
+
+	parse_error(sb, compare->lval->field.raw,
+		    "Simple SQL (without JOIN/ON) do not allow comparisons\n",
+		    compare->lval->field.raw, compare->rval->field.raw);
+}
+
+static void where_no_to_error(struct sqlhist_bison *sb, struct expr *expr,
+			      const char *from_event, const char *event)
+{
+	while (expr) {
+		switch (expr->filter.type) {
+		case FILTER_OR:
+		case FILTER_AND:
+		case FILTER_GROUP:
+		case FILTER_NOT_GROUP:
+			expr = expr->filter.lval;
+			continue;
+		default:
+			break;
+		}
+		break;
+	}
+	sb->line_no = expr->filter.lval->line;
+	sb->line_idx = expr->filter.lval->idx;
+
+	parse_error(sb, expr->filter.lval->field.raw,
+		    "Event '%s' does not match FROM event '%s'\n",
+		    event, from_event);
+}
+
+static int verify_field_type(struct tep_handle *tep,
+			     struct sqlhist_bison *sb,
+			     struct expr *expr, int *cnt)
+{
+	struct field *field = &expr->field;
+	struct tep_event *event;
+	struct tep_format_field *tfield;
+	char *type;
+	int ret;
+	int i;
+
+	if (!field->type)
+		return 0;
+
+	sb->line_no = expr->line;
+	sb->line_idx = expr->idx;
+
+	event = tep_find_event_by_name(tep, field->system, field->event_name);
+	if (!event) {
+		parse_error(sb, field->raw,
+			    "Event '%s' not found\n",
+			    field->event_name ? : "(null)");
+		return -1;
+	}
+
+	tfield = tep_find_any_field(event, field->field);
+	if (!tfield) {
+		parse_error(sb, field->raw,
+			    "Field '%s' not part of event '%s'\n",
+			    field->field ? : "(null)", field->event);
+		return -1;
+	}
+
+	type = strdup(field->type);
+	if (!type)
+		return -1;
+
+	if (!strcmp(type, TRACEFS_HIST_COUNTER) ||
+	    !strcmp(type, "_COUNTER_")) {
+		ret = HIST_COUNTER_TYPE;
+		if (tfield->flags & (TEP_FIELD_IS_STRING | TEP_FIELD_IS_ARRAY)) {
+			parse_error(sb, field->raw,
+				    "'%s' is a string, and counters may only be used with numbers\n");
+			ret = -1;
+		}
+		goto out;
+	}
+
+	for (i = 0; type[i]; i++)
+		type[i] = tolower(type[i]);
+
+	if (!strcmp(type, "hex")) {
+		if (tfield->flags & (TEP_FIELD_IS_STRING | TEP_FIELD_IS_ARRAY))
+			goto fail_type;
+		ret = TRACEFS_HIST_KEY_HEX;
+	} else if (!strcmp(type, "sym")) {
+		if (tfield->flags & (TEP_FIELD_IS_STRING | TEP_FIELD_IS_ARRAY))
+			goto fail_type;
+		ret = TRACEFS_HIST_KEY_SYM;
+	} else if (!strcmp(type, "sym-offset")) {
+		if (tfield->flags & (TEP_FIELD_IS_STRING | TEP_FIELD_IS_ARRAY))
+			goto fail_type;
+		ret = TRACEFS_HIST_KEY_SYM_OFFSET;
+	} else if (!strcmp(type, "syscall")) {
+		if (tfield->flags & (TEP_FIELD_IS_STRING | TEP_FIELD_IS_ARRAY))
+			goto fail_type;
+		ret = TRACEFS_HIST_KEY_SYSCALL;
+	} else if (!strcmp(type, "execname") ||
+		   !strcmp(type, "comm")) {
+		ret = TRACEFS_HIST_KEY_EXECNAME;
+		if (strcmp(field->field, "common_pid")) {
+			parse_error(sb, field->raw,
+				    "'%s' is only allowed for common_pid\n",
+				    type);
+			ret = -1;
+		}
+	} else if (!strcmp(type, "log") ||
+		   !strcmp(type, "log2")) {
+		if (tfield->flags & (TEP_FIELD_IS_STRING | TEP_FIELD_IS_ARRAY))
+			goto fail_type;
+		ret = TRACEFS_HIST_KEY_LOG;
+	} else if (!strncmp(type, "buckets", 7)) {
+		if (type[7] != '=' || !isdigit(type[8])) {
+			parse_error(sb, field->raw,
+				    "buckets type must have '=[number]' after it\n");
+			ret = -1;
+			goto out;
+		}
+		*cnt = atoi(&type[8]);
+		if (tfield->flags & (TEP_FIELD_IS_STRING | TEP_FIELD_IS_ARRAY))
+			goto fail_type;
+		ret = TRACEFS_HIST_KEY_BUCKETS;
+	} else {
+		parse_error(sb, field->raw,
+			    "Cast of '%s' to unknown type '%s'\n",
+			    field->raw, type);
+		ret = -1;
+	}
+ out:
+	free(type);
+	return ret;
+ fail_type:
+	parse_error(sb, field->raw,
+		    "Field '%s' cast to '%s' but is of type %s\n",
+		    field->field, type, tfield->flags & TEP_FIELD_IS_STRING ?
+		    "string" : "array");
+	free(type);
+	return -1;
+}
+
+static struct tracefs_synth *build_synth(struct tep_handle *tep,
+					 const char *name,
+					 struct sql_table *table)
+{
+	struct tracefs_synth *synth;
+	struct field *field;
+	struct match *match;
+	struct expr *expr;
+	const char *start_system;
+	const char *start_event;
+	const char *end_system;
+	const char *end_event;
+	const char *start_match;
+	const char *end_match;
+	bool started_start = false;
+	bool started_end = false;
+	bool non_val = false;
+	int ret;
+
+	if (!table->from)
+		return NULL;
+
+	/* This could be a simple SQL statement to only build a histogram */
+	if (!table->to) {
+		ret = update_fields(tep, table, table->from);
+		if (ret < 0)
+			return NULL;
+
+		start_system = table->from->field.system;
+		start_event = table->from->field.event_name;
+
+		synth = synth_init_from(tep, start_system, start_event);
+		if (!synth)
+			return synth_init_error(tep, table);
+		goto hist_only;
+	}
+
+	ret = update_vars(tep, table, table->from);
+	if (ret < 0)
+		return NULL;
+
+	ret = update_vars(tep, table, table->to);
+	if (ret < 0)
+		return NULL;
+
+	start_system = table->from->field.system;
+	start_event = table->from->field.event_name;
+
+	match = table->matches;
+	if (!match)
+		return NULL;
+
+	ret = test_match(table, match);
+	if (ret < 0)
+		return NULL;
+
+	end_system = table->to->field.system;
+	end_event = table->to->field.event_name;
+
+	assign_match(start_system, start_event, match,
+		     &start_match, &end_match);
+
+	synth = tracefs_synth_alloc(tep, name, start_system,
+				    start_event, end_system, end_event,
+				    start_match, end_match, NULL);
+	if (!synth)
+		return synth_init_error(tep, table);
+
+	for (match = match->next; match; match = match->next) {
+		ret = test_match(table, match);
+		if (ret < 0)
+			goto free;
+
+		assign_match(start_system, start_event, match,
+			     &start_match, &end_match);
+
+		ret = tracefs_synth_add_match_field(synth,
+						    start_match,
+						    end_match, NULL);
+		if (ret < 0) {
+			field_match_error(tep, table->sb, match);
+			goto free;
+		}
+	}
+
+ hist_only:
+	/* table->to may be NULL here */
+
+	for (expr = table->selections; expr; expr = expr->next) {
+		if (expr->type == EXPR_FIELD) {
+			ret = -1;
+			field = &expr->field;
+			if (field->ftype != FIELD_TO &&
+			    field->system == start_system &&
+			    field->event_name == start_event) {
+				int type;
+				int cnt = 0;
+				type = verify_field_type(tep, table->sb, expr, &cnt);
+				if (type < 0)
+					goto free;
+				if (type != HIST_COUNTER_TYPE)
+					non_val = true;
+				ret = synth_add_start_field(synth,
+						field->field, field->label,
+						type, cnt);
+			} else if (table->to) {
+				ret = tracefs_synth_add_end_field(synth,
+						field->field, field->label);
+			}
+			if (ret < 0) {
+				selection_error(tep, table->sb, expr);
+				goto free;
+			}
+			continue;
+		}
+
+		if (!table->to) {
+			compare_no_to_error(table->sb, expr);
+			goto free;
+		}
+
+		if (expr->type != EXPR_COMPARE)
+			goto free;
+
+		ret = build_compare(synth, start_system, end_system,
+				    &expr->compare);
+		if (ret < 0) {
+			compare_error(tep, table->sb, expr);
+			goto free;
+		}
+	}
+
+	if (!non_val && !table->to) {
+		table->sb->line_no = 0;
+		table->sb->line_idx = 10;
+		parse_error(table->sb, "CAST",
+			    "Not all SELECT items can be of type _COUNTER_\n");
+		goto free;
+	}
+
+	for (expr = table->where; expr; expr = expr->next) {
+		const char *filter_system = NULL;
+		const char *filter_event = NULL;
+		enum field_type ftype = FIELD_NONE;
+		bool *started;
+		bool start;
+
+		ret = verify_filter(table->sb, &expr->filter, &filter_system,
+				    &filter_event, &ftype);
+		if (ret < 0)
+			goto free;
+
+		start = filter_system == start_system &&
+			filter_event == start_event &&
+			ftype != FIELD_TO;
+
+		if (start)
+			started = &started_start;
+		else if (!table->to) {
+			where_no_to_error(table->sb, expr, start_event,
+					  filter_event);
+			goto free;
+		} else
+			started = &started_end;
+
+		ret = build_filter(tep, table->sb, synth, start, expr, started);
+		if (ret < 0)
+			goto free;
+	}
+
+	return synth;
+ free:
+	tracefs_synth_free(synth);
+	return NULL;
+}
+
+static void free_sql_table(struct sql_table *table)
+{
+	struct match *match;
+	struct expr *expr;
+
+	if (!table)
+		return;
+
+	while ((expr = table->exprs)) {
+		table->exprs = expr->free_list;
+		free(expr);
+	}
+
+	while ((match = table->matches)) {
+		table->matches = match->next;
+		free(match);
+	}
+
+	free(table);
+}
+
+static void free_str_hash(struct str_hash **hash)
+{
+	struct str_hash *item;
+	int i;
+
+	for (i = 0; i < 1 << HASH_BITS; i++) {
+		while ((item = hash[i])) {
+			hash[i] = item->next;
+			free(item->str);
+			free(item);
+		}
+	}
+}
+
+static void free_sb(struct sqlhist_bison *sb)
+{
+	free_sql_table(sb->table);
+	free_str_hash(sb->str_hash);
+	free(sb->parse_error_str);
+}
+
+struct tracefs_synth *tracefs_sql(struct tep_handle *tep, const char *name,
+				  const char *sql_buffer, char **err)
+{
+	struct tracefs_synth *synth = NULL;
+	struct sqlhist_bison sb;
+	int ret;
+
+	if (!tep || !sql_buffer) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	memset(&sb, 0, sizeof(sb));
+
+	sb.buffer = sql_buffer;
+	sb.buffer_size = strlen(sql_buffer);
+	sb.buffer_idx = 0;
+
+	ret = yylex_init_extra(&sb, &sb.scanner);
+	if (ret < 0) {
+		yylex_destroy(sb.scanner);
+		return NULL;
+	}
+
+	ret = tracefs_parse(&sb);
+	yylex_destroy(sb.scanner);
+
+	if (ret)
+		goto free;
+
+	synth = build_synth(tep, name, sb.table);
+
+ free:
+	if (!synth) {
+		if (sb.parse_error_str && err) {
+			*err = sb.parse_error_str;
+			sb.parse_error_str = NULL;
+		}
+	}
+	free_sb(&sb);
+	return synth;
+}