trace-cmd: Add -P option to record a single pid

Add the -P option to trace-cmd record (and start) to only trace
a given pid. This is just like -F command where the pid given to
-P would be the pid of the command.

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

1 files changed, 19 insertions, 4 deletions

diff --git a/trace-cmd.c b/trace-cmd.c
index 2b246df..e89362d 100644
--- a/trace-cmd.c
+++ b/trace-cmd.c
@@ -58,6 +58,7 @@ static int cpu_count;
 static int *pids;
 
 static int filter_task;
+static int filter_pid = -1;
 
 struct func_list {
         struct func_list *next;
@@ -309,12 +310,15 @@ static void update_task_filter(void)
         int pid = getpid();
         char spid[100];
 
-        if (!filter_task) {
+        if (!filter_task && filter_pid < 0) {
                 update_ftrace_pid("");
                 enable_tracing();
                 return;
         }
 
+        if (filter_pid >= 0)
+                pid = filter_pid;
+
         snprintf(spid, 100, "%d", pid);
 
         update_ftrace_pid(spid);
@@ -1061,11 +1065,13 @@ void usage(char **argv)
                "%s version %s\n\n"
                "usage:\n"
                " %s record [-v][-e event [-f filter]][-p plugin][-F][-d][-o file] \\\n"
-               "           [-s usecs][-O option ][-l func][-g func][-n func][command ...]\n"
+               "           [-s usecs][-O option ][-l func][-g func][-n func]\n"
+               "           [-P pid][command ...]\n"
                "          -e run command with event enabled\n"
                "          -f filter for previous -e event\n"
                "          -p run command with plugin enabled\n"
                "          -F filter only on the given process\n"
+               "          -P trace the given pid like -F for the command\n"
                "          -l filter function name\n"
                "          -g set graph function\n"
                "          -n do not trace function\n"
@@ -1075,7 +1081,7 @@ void usage(char **argv)
                "          -O option to enable (or disable)\n"
                "          -s sleep interval between recording (in usecs) [default: 1000]\n"
                "\n"
-               " %s start [-e event][-p plugin] [-d] [-O option ]\n"
+               " %s start [-e event][-p plugin][-d][-O option ][-P pid]\n"
                "          Uses same options as record, but does not run a command.\n"
                "          It only enables the tracing and exits\n"
                "\n"
@@ -1160,7 +1166,7 @@ int main (int argc, char **argv)
                    (strcmp(argv[1], "start") == 0) ||
                    ((extract = strcmp(argv[1], "extract") == 0))) {
 
-                while ((c = getopt(argc-1, argv+1, "+he:f:Fp:do:O:s:vg:l:n:")) >= 0) {
+                while ((c = getopt(argc-1, argv+1, "+he:f:Fp:do:O:s:vg:l:n:P:")) >= 0) {
                         switch (c) {
                         case 'h':
                                 usage(argv);
@@ -1198,8 +1204,17 @@ int main (int argc, char **argv)
                                 break;
 
                         case 'F':
+                                if (filter_pid >= 0)
+                                        die("-P and -F can not both be specified");
                                 filter_task = 1;
                                 break;
+                        case 'P':
+                                if (filter_task)
+                                        die("-P and -F can not both be specified");
+                                if (filter_pid >= 0)
+                                        die("only one -P pid can be filtered at a time");
+                                filter_pid = atoi(optarg);
+                                break;
                         case 'v':
                                 if (extract)
                                         usage(argv);