[ I just realized I already pushed your patch. Here's an update to what
I would like. ]
From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Instead of forking a command specified on the command line and returning
right away, have it wait for the process to finish before returning. Unless
"--fork" is specified as well.
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
Documentation/trace-cmd-start.1.txt | 7 +++++++
tracecmd/trace-record.c | 18 +++++++++++++-----
tracecmd/trace-usage.c | 2 ++
3 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/Documentation/trace-cmd-start.1.txt b/Documentation/trace-cmd-start.1.txt
index 63d2034c..07f2ed3a 100644
--- a/Documentation/trace-cmd-start.1.txt
+++ b/Documentation/trace-cmd-start.1.txt
@@ -23,6 +23,13 @@ OPTIONS
The options are the same as 'trace-cmd-record(1)', except that it does not
take options specific to recording (*-s*, *-o*, *-N*, and *-t*).
+*--fork* ::
+ This option is only available for trace-cmd start. It tells trace-cmd
+ to not wait for the process to finish before returning.
+ With this option, trace-cmd start will return right after it forks
+ the process on the command line. This option only has an effect if
+ trace-cmd start also executes a command.
+
SEE ALSO
--------
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-stop(1),
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 4d2039a1..143b736e 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -86,6 +86,8 @@ static char *host;
static bool quiet;
+static bool fork_process;
+
/* Max size to let a per cpu file get */
static int max_kb;
@@ -1604,7 +1606,7 @@ static void run_cmd(enum trace_type type, const char *user, int argc, char **arg
/* child */
update_task_filter();
tracecmd_enable_tracing();
- if (type != TRACE_TYPE_START)
+ if (!fork_process)
enable_ptrace();
/*
* If we are using stderr for stdout, switch
@@ -1626,13 +1628,15 @@ static void run_cmd(enum trace_type type, const char *user, int argc, char **arg
die("Failed to exec %s", argv[0]);
}
}
- if (type & TRACE_TYPE_START)
+ if (fork_process)
exit(0);
if (do_ptrace) {
ptrace_attach(NULL, pid);
ptrace_wait(type);
} else
trace_waitpid(type, pid, &status, 0);
+ if (type & TRACE_TYPE_START)
+ exit(0);
}
static void
@@ -5535,6 +5539,7 @@ void init_top_instance(void)
}
enum {
+ OPT_fork = 241,
OPT_tsyncinterval = 242,
OPT_user = 243,
OPT_procmap = 244,
@@ -5851,6 +5856,7 @@ static void parse_record_options(int argc,
{"user", required_argument, NULL, OPT_user},
{"module", required_argument, NULL, OPT_module},
{"tsync-interval", required_argument, NULL, OPT_tsyncinterval},
+ {"fork", no_argument, NULL, OPT_fork},
{NULL, 0, NULL, 0}
};
@@ -6204,6 +6210,11 @@ static void parse_record_options(int argc,
top_instance.tsync.loop_interval = atoi(optarg);
guest_sync_set = true;
break;
+ case OPT_fork:
+ if (!IS_START(ctx))
+ die("--fork option used for 'start' command only");
+ fork_process = true;
+ break;
case OPT_quiet:
case 'q':
quiet = true;
@@ -6266,9 +6277,6 @@ static void parse_record_options(int argc,
}
}
- if (do_ptrace && IS_START(ctx))
- die("ptrace not supported with command start");
-
for_all_instances(instance) {
if (instance->get_procmap && !instance->nr_filter_pids) {
warning("--proc-map is ignored for instance %s, "
diff --git a/tracecmd/trace-usage.c b/tracecmd/trace-usage.c
index 58bca9e4..1e832be8 100644
--- a/tracecmd/trace-usage.c
+++ b/tracecmd/trace-usage.c
@@ -71,6 +71,8 @@ static struct usage_help usage_help[] = {
" %s start [-e event][-p plugin][-d][-O option ][-P pid]\n"
" Uses same options as record.\n"
" It only enables the tracing and exits\n"
+ "\n"
+ " --fork: If a command is specified, then return right after it forks\n"
},
{
"extract",
--
2.25.4
|