[PATCH 6/7] libtracefs: Update the libtracefs-sql man page for the new tracefs_synth APIs

From: Steven Rostedt
Date: Thu Aug 12 2021 - 22:17:50 EST


From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>

Update the libtracfes-sql man page to have the sqlhist program utilize the
new APIs:

tracefs_synth_trace()
tracefs_synth_snapshot()
tracefs_synth_save()

Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
Documentation/libtracefs-sql.txt | 105 ++++++++++++++++++++++++++--
Documentation/libtracefs-synth2.txt | 2 +
2 files changed, 102 insertions(+), 5 deletions(-)

diff --git a/Documentation/libtracefs-sql.txt b/Documentation/libtracefs-sql.txt
index 35ccaf5cd1a5..95625157590e 100644
--- a/Documentation/libtracefs-sql.txt
+++ b/Documentation/libtracefs-sql.txt
@@ -305,23 +305,47 @@ EXAMPLE

static void usage(char **argv)
{
- fprintf(stderr, "usage: %s [-ed][-n name][-t dir][-f file | sql-command-line]\n"
+ fprintf(stderr, "usage: %s [-ed][-n name][-s][-S fields][-m var][-c var][-T][-t dir][-f file | sql-command-line]\n"
" -n name - name of synthetic event 'Anonymous' if left off\n"
" -t dir - use dir instead of /sys/kernel/tracing\n"
" -e - execute the commands to create the synthetic event\n"
+ " -m - trigger the action when var is a new max.\n"
+ " -c - trigger the action when var changes.\n"
+ " -s - used with -m or -c to do a snapshot of the tracing buffer\n"
+ " -S - used with -m or -c to save fields of the end event (comma deliminated)\n"
+ " -T - used with -m or -c to do both a snapshot and a trace\n"
" -f file - read sql lines from file otherwise from the command line\n"
" if file is '-' then read from standard input.\n",
argv[0]);
exit(-1);
}

-static int do_sql(const char *buffer, const char *name,
- const char *trace_dir, bool execute)
+enum action {
+ ACTION_DEFAULT = 0,
+ ACTION_SNAPSHOT = (1 << 0),
+ ACTION_TRACE = (1 << 1),
+ ACTION_SAVE = (1 << 2),
+ ACTION_MAX = (1 << 3),
+ ACTION_CHANGE = (1 << 4),
+};
+
+#define ACTIONS ((ACTION_MAX - 1))
+
+static int do_sql(const char *buffer, const char *name, const char *var,
+ const char *trace_dir, bool execute, int action,
+ char **save_fields)
{
struct tracefs_synth *synth;
struct tep_handle *tep;
struct trace_seq seq;
+ enum tracefs_synth_handler handler;
char *err;
+ int ret;
+
+ if ((action & ACTIONS) && !var) {
+ fprintf(stderr, "Error: -s, -S and -T not supported without -m or -c");
+ exit(-1);
+ }

if (!name)
name = "Anonymous";
@@ -345,6 +369,43 @@ static int do_sql(const char *buffer, const char *name,
}

if (tracefs_synth_complete(synth)) {
+ if (var) {
+ if (action & ACTION_MAX)
+ handler = TRACEFS_SYNTH_HANDLE_MAX;
+ else
+ handler = TRACEFS_SYNTH_HANDLE_CHANGE;
+
+ if (action & ACTION_SAVE) {
+ ret = tracefs_synth_save(synth, handler, var, save_fields);
+ if (ret < 0) {
+ err = "adding save";
+ goto failed_action;
+ }
+ }
+ if (action & ACTION_TRACE) {
+ /*
+ * By doing the trace before snapshot, it will be included
+ * in the snapshot.
+ */
+ ret = tracefs_synth_trace(synth, handler, var);
+ if (ret < 0) {
+ err = "adding trace";
+ goto failed_action;
+ }
+ }
+ if (action & ACTION_SNAPSHOT) {
+ ret = tracefs_synth_snapshot(synth, handler, var);
+ if (ret < 0) {
+ err = "adding snapshot";
+ failed_action:
+ perror(err);
+ if (errno == ENODEV)
+ fprintf(stderr, "ERROR: '%s' is not a variable\n",
+ var);
+ exit(-1);
+ }
+ }
+ }
tracefs_synth_show(&seq, NULL, synth);
if (execute)
tracefs_synth_create(NULL, synth);
@@ -375,14 +436,18 @@ int main (int argc, char **argv)
int buffer_size = 0;
const char *file = NULL;
bool execute = false;
+ char **save_fields = NULL;
const char *name;
+ const char *var;
+ int action = 0;
+ char *tok;
FILE *fp;
size_t r;
int c;
int i;

for (;;) {
- c = getopt(argc, argv, "ht:f:en:");
+ c = getopt(argc, argv, "ht:f:en:m:c:sS:T");
if (c == -1)
break;

@@ -398,12 +463,42 @@ int main (int argc, char **argv)
case 'e':
execute = true;
break;
+ case 'm':
+ action |= ACTION_MAX;
+ var = optarg;
+ break;
+ case 'c':
+ action |= ACTION_CHANGE;
+ var = optarg;
+ break;
+ case 's':
+ action |= ACTION_SNAPSHOT;
+ break;
+ case 'S':
+ action |= ACTION_SAVE;
+ tok = strtok(optarg, ",");
+ while (tok) {
+ save_fields = tracefs_list_add(save_fields, tok);
+ tok = strtok(NULL, ",");
+ }
+ if (!save_fields) {
+ perror(optarg);
+ exit(-1);
+ }
+ break;
+ case 'T':
+ action |= ACTION_TRACE | ACTION_SNAPSHOT;
+ break;
case 'n':
name = optarg;
break;
}
}

+ if ((action & (ACTION_MAX|ACTION_CHANGE)) == (ACTION_MAX|ACTION_CHANGE)) {
+ fprintf(stderr, "Can not use both -m and -c together\n");
+ exit(-1);
+ }
if (file) {
if (!strcmp(file, "-"))
fp = stdin;
@@ -434,7 +529,7 @@ int main (int argc, char **argv)
}
}

- do_sql(buffer, name, trace_dir, execute);
+ do_sql(buffer, name, var, trace_dir, execute, action, save_fields);
free(buffer);

return 0;
diff --git a/Documentation/libtracefs-synth2.txt b/Documentation/libtracefs-synth2.txt
index cfcae7411f58..4c4425325393 100644
--- a/Documentation/libtracefs-synth2.txt
+++ b/Documentation/libtracefs-synth2.txt
@@ -117,6 +117,8 @@ And more errors may have happened from the system calls to the system.

EXAMPLE
-------
+See *tracefs_sql*(3) for a more indepth use of some of this code.
+
[source,c]
--
#include <stdlib.h>
--
2.30.2