trace-cmd: Add negating of events

Add the '-v' option to disable events. This is advantageous with:

 trace-cmd record -e all -v -e lock -e syscalls

This will enable all events and then disable lock and syscall events
before executing the command.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 34 insertions, 3 deletions

diff --git a/trace-cmd.c b/trace-cmd.c
index 879d9ad..ac14a61 100644
--- a/trace-cmd.c
+++ b/trace-cmd.c
@@ -58,6 +58,7 @@ static int *pids;
 struct event_list {
         struct event_list *next;
         const char *event;
+        int neg;
 };
 
 static struct event_list *event_selection;
@@ -424,7 +425,24 @@ static void disable_event(const char *name)
                 put_tracing_file(path);
                 fwrite("0", 1, 1, fp);
                 fclose(fp);
+                return;
         }
+
+        path = get_tracing_file("set_event");
+        fp = fopen(path, "a");
+        if (!fp)
+                die("writing to '%s'", path);
+        put_tracing_file(path);
+        ret = fwrite("!", 1, 1, fp);
+        if (ret < 0)
+                die("can't write negative");
+        ret = fwrite(name, 1, strlen(name), fp);
+        if (ret < 0)
+                die("bad event '%s'", name);
+        ret = fwrite("\n", 1, 1, fp);
+        if (ret < 0)
+                die("bad event '%s'", name);
+        fclose(fp);
 }
 
 static void enable_tracing(void)
@@ -497,7 +515,14 @@ static void enable_events(void)
         struct event_list *event;
 
         for (event = event_selection; event; event = event->next) {
-                enable_event(event->event);
+                if (!event->neg)
+                        enable_event(event->event);
+        }
+
+        /* Now disable any events */
+        for (event = event_selection; event; event = event->next) {
+                if (event->neg)
+                        disable_event(event->event);
         }
 }
 
@@ -631,9 +656,10 @@ void usage(char **argv)
         printf("\n"
                "%s version %s\n\n"
                "usage:\n"
-               " %s record [-e event][-p plugin][-d][-o file][-s usecs][-O option ] [command ...]\n"
+               " %s record [-v][-e event][-p plugin][-d][-o file][-s usecs][-O option ] [command ...]\n"
                "          -e run command with event enabled\n"
                "          -p run command with plugin enabled\n"
+               "          -v will negate all -e after it (disable those events)\n"
                "          -d disable function tracer when running\n"
                "          -o data output file [default trace.dat]\n"
                "          -O option to enable (or disable)\n"
@@ -680,6 +706,7 @@ int main (int argc, char **argv)
         int options = 0;
         int record = 0;
         int run_command = 0;
+        int neg_event = 0;
         int fset;
         int cpu;
 
@@ -696,7 +723,7 @@ int main (int argc, char **argv)
         } else if ((record = (strcmp(argv[1], "record") == 0)) ||
                    (strcmp(argv[1], "start") == 0)) {
 
-                while ((c = getopt(argc-1, argv+1, "+he:p:do:O:")) >= 0) {
+                while ((c = getopt(argc-1, argv+1, "+he:p:do:O:s:v")) >= 0) {
                         switch (c) {
                         case 'h':
                                 usage(argv);
@@ -706,8 +733,12 @@ int main (int argc, char **argv)
                                 event = malloc_or_die(sizeof(*event));
                                 event->event = optarg;
                                 event->next = event_selection;
+                                event->neg = neg_event;
                                 event_selection = event;
                                 break;
+                        case 'v':
+                                neg_event = 1;
+                                break;
                         case 'p':
                                 if (plugin)
                                         die("only one plugin allowed");