LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Steven Rostedt <rostedt@goodmis.org>
To: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Tom Zanussi <zanussi@kernel.org>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	Clark Williams <williams@redhat.com>,
	"Steven Rostedt (VMware)" <rostedt@goodmis.org>
Subject: [PATCH v3 20/22] libtracefs: Allow trace_sql() to take keywords for fields with backslash
Date: Tue,  3 Aug 2021 13:06:04 -0400	[thread overview]
Message-ID: <20210803170606.694085-21-rostedt@goodmis.org> (raw)
In-Reply-To: <20210803170606.694085-1-rostedt@goodmis.org>

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Some events have fields with keywords, and the parsing will not let it
work. For example, you can have:

  select from from regcache_drop_region

And that will produce a syntax error, as the from will confuse the parser.
Allow fields to start with a backslash, which will allow the parser to see
"from" as a field and not as a keyword. That is:

  select \from from regcache_drop_region

will work as expected. Note, any field can start with a backslash, and the
starting backslash will be ignored.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Documentation/libtracefs-sql.txt | 20 ++++++++++++++++++++
 src/sqlhist.l                    |  6 ++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/Documentation/libtracefs-sql.txt b/Documentation/libtracefs-sql.txt
index ee8d5c1d63c7..bc2811cfe08b 100644
--- a/Documentation/libtracefs-sql.txt
+++ b/Documentation/libtracefs-sql.txt
@@ -162,6 +162,26 @@ select start.pid, (end.TIMESTAMP_USECS - start.TIMESTAMP_USECS) as lat from sche
    WHERE start.prio < 100 || end.prev_prio < 100
 --
 
+
+KEYWORDS AS EVENT FIELDS
+------------------------
+
+In some cases, an event may have a keyword. For example, regcache_drop_region has "from"
+as a field and the following will not work
+
+[source,c]
+--
+  select from from regcache_drop_region
+--
+
+In such cases, add a backslash to the conflicting field, and this will tell the parser
+that the "from" is a field and not a keyword:
+
+[source,c]
+--
+  select \from from regcache_drop_region
+--
+
 HISTOGRAMS
 ----------
 
diff --git a/src/sqlhist.l b/src/sqlhist.l
index f9e0fcc17e63..897daac7d2a8 100644
--- a/src/sqlhist.l
+++ b/src/sqlhist.l
@@ -25,7 +25,7 @@ extern int my_yyinput(void *extra, char *buf, int max);
 %option reentrant
 %option bison-bridge
 
-field		[a-z_][a-z0-9_\.]*
+field		\\?[a-z_][a-z0-9_\.]*
 qstring		\"[^\"]*\"
 hexnum		0x[0-9a-f]+
 number		[0-9a-f]+
@@ -46,8 +46,10 @@ where { HANDLE_COLUMN; return WHERE; }
 }
 
 {field} {
+	const char *str = yyg->yytext_r;
 	HANDLE_COLUMN;
-	yylval->string = store_str(TRACE_SB, yyg->yytext_r);
+	if (str[0] == '\\') { str++; };
+	yylval->string = store_str(TRACE_SB, str);
 	return FIELD;
 }
 
-- 
2.30.2


  parent reply	other threads:[~2021-08-03 17:06 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-03 17:05 [PATCH v3 00/22] libtracefs: Introducing tracefs_sql() to create synthetice events with an SQL line Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 01/22] libtracefs: Added new API tracefs_sql() Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 02/22] tracefs: Add unit tests for tracefs_sql() Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 03/22] libtracefs: Add comparing start and end fields in tracefs_sql() Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 04/22] libtracefs: Add unit test to test tracefs_sql() compare Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 05/22] libtracefs: Add filtering for start and end events in tracefs_sql() Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 06/22] libtracefs: Add unit test to test tracefs_sql() where clause Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 07/22] libtracefs: Make sqlhist parser reentrant Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 08/22] libtracefs: Make parser unique to libtracefs Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 09/22] libtracefs: Add line number and index to expr structure Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 10/22] libtracefs: Add error message when match fields are not FROM and JOIN events Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 11/22] libtracefs: Add error message when match or init fails from bad events Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 12/22] libtracefs; Add error message for bad selections to SQL sequence Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 13/22] libtracefs: Add error message when compare fields fail Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 14/22] libtracefs: Add error message for grouping events in SQL filter Steven Rostedt
2021-08-03 17:05 ` [PATCH v3 15/22] libtracefs: Add error message for bad filters in SQL statement Steven Rostedt
2021-08-03 17:06 ` [PATCH v3 16/22] libtracefs: Add error message when calculation has no label Steven Rostedt
2021-08-03 17:06 ` [PATCH v3 17/22] libtracefs: Add man page for tracefs_sql() Steven Rostedt
2021-08-03 17:06 ` [PATCH v3 18/22] libtracefs: Add Makefile rule to create sqlhist Steven Rostedt
2021-08-03 17:06 ` [PATCH v3 19/22] libtracefs: Allow for simple SQL statements to create a histogram Steven Rostedt
2021-08-03 17:06 ` Steven Rostedt [this message]
2021-08-03 17:06 ` [PATCH v3 21/22] libtracefs: Add CAST() syntax to SQL parsing for histogram types Steven Rostedt
2021-08-03 17:06 ` [PATCH v3 22/22] libtracefs: Add CAST(x AS _COUNTER_) syntax to create values in histograms Steven Rostedt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210803170606.694085-21-rostedt@goodmis.org \
    --to=rostedt@goodmis.org \
    --cc=bristot@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rt-users@vger.kernel.org \
    --cc=linux-trace-devel@vger.kernel.org \
    --cc=mhiramat@kernel.org \
    --cc=namhyung@kernel.org \
    --cc=williams@redhat.com \
    --cc=zanussi@kernel.org \
    --subject='Re: [PATCH v3 20/22] libtracefs: Allow trace_sql() to take keywords for fields with backslash' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).