From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Add an API that sets and clears PID filtering for functions and events.
tracefs_filter_pid_function()
tracefs_filter_pid_events()
tracefs_filter_pid_function_clear()
tracefs_filter_pid_events_clear()
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
Documentation/libtracefs-filter-pid.txt | 181 +++++++++++++++++
Documentation/libtracefs.txt | 8 +
include/tracefs.h | 7 +
src/tracefs-filter.c | 132 ++++++++++++
utest/tracefs-utest.c | 257 +++++++++++++++++++++++-
5 files changed, 577 insertions(+), 8 deletions(-)
create mode 100644 Documentation/libtracefs-filter-pid.txt
diff --git a/Documentation/libtracefs-filter-pid.txt b/Documentation/libtracefs-filter-pid.txt
new file mode 100644
index 000000000000..fa56b0222df0
--- /dev/null
+++ b/Documentation/libtracefs-filter-pid.txt
@@ -0,0 +1,181 @@
+libtracefs(3)
+=============
+
+NAME
+----
+tracefs_filter_pid_function, tracefs_filter_pid_events, tracefs_filter_pid_function_clear, tracefs_filter_pid_events_clear -
+Add and remove PID filtering for functions and events
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <tracefs.h>*
+
+int *tracefs_filter_pid_function*(struct tracefs_instance pass:[*]_instance,_ int _pid_,
+ bool _reset_, bool _notrace_);
+int *tracefs_filter_pid_function_clear*(struct tracefs_instance pass:[*]_instance_, bool _notrace_);
+int *tracefs_filter_pid_events*(struct tracefs_instance pass:[*]_instance_, int _pid_,
+ bool _reset_, bool _notrace_);
+int *tracefs_filter_pid_events_clear*(struct tracefs_instance pass:[*]_instance_, bool _notrace_);
+--
+
+DESCRIPTION
+-----------
+Both events and functions can be filtered by PID, but they are done separately.
+PID filtering for functions affect the function and function_graph tracer, where
+as PID filtering for events affect all events such as _sched_switch_ and _sched_waking_.
+If the *TRACEFS_OPTION_FUNCTION_FORK* is enabled (see *tracefs_option_enable*(3)),
+any PID that is set as part of the function PID filtering will automatically
+have its children added when they are spawned, as well as the PID removed when
+they exit. If the *TRACEFS_OPTION_EVENT_FORK* is set, the same is true for
+event PID filtering. This also includes the _notrace_ option where the child
+threads and processes of PIDs that are labled as notrace will also not be
+traced.
+
+The *tracefs_filter_pid_function()* affects function PID filtering and *tracefs_filter_pid_events()*
+affects the PID event filtering. For both functions, they add a _pid_ to be filtered in the given _instance_.
+If _reset_ is true, then any PIDs already being filtered will be removed, otherwise
+the _pid_ is simply added to the filtering. If _notrace_ is true, then the PID
+is added to the list of PIDs that are not to be traced. Note, that _reset_ only affects
+the list associated with _notrace_. That is, if both _reset_ and _notrace_ are true,
+then it will not affect PIDs that are to be traced. Same is if _reset_ is true and _notrace_
+is false, it will not affect PIDs that are not to be traced.
+
+The *tracefs_filter_pid_function_clear()* affects function PID filtering and
+*tracefs_filter_pid_events_clear()* affects the PID event filtering. For both
+functions it will clear all the PIDs that are being filtered for the given
+filter. If _notrace_ is true it clears all the PIDs that are not to be traced
+otherwise if it is false, it clears all the PIDs that are to be traced.
+
+RETURN VALUE
+------------
+All the functions return 0 on success and -1 on error.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <stdlib.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <tracefs.h>
+
+static void usage(char **argv)
+{
+ fprintf(stderr, "usage: %s [-e|-f][-c|-n] pid [pid ...]\n", argv[0]);
+ fprintf(stderr, " -e enable event filter\n");
+ fprintf(stderr, " -f enable function filter\n");
+ fprintf(stderr, " (default is both, function and event)\n");
+ fprintf(stderr, " -c clear the filter\n");
+ fprintf(stderr, " -n notrace filter\n");
+ exit(-1);
+}
+
+int main (int argc, char **argv)
+{
+ bool events = false;
+ bool funcs = false;
+ bool neg = false;
+ bool clear = false;
+ bool reset = true;
+ int i;
+
+ for (i = 1; i < argc && argv[i][0] == '-'; i++) {
+ char *arg = argv[i];
+ int c;
+ for (c = 1; arg[c]; c++) {
+ switch (arg[c]) {
+ case 'e': events = true; break;
+ case 'f': funcs = true; break;
+ case 'n': neg = true; break;
+ case 'c': clear = true; break;
+ default:
+ usage(argv);
+ }
+ }
+ if (c == 1)
+ usage(argv);
+ }
+
+ if (i == argc && !clear)
+ usage(argv);
+
+ if (!events && !funcs) {
+ events = true;
+ funcs = true;
+ }
+
+ if (clear) {
+ if (events)
+ tracefs_filter_pid_events_clear(NULL, neg);
+ if (funcs)
+ tracefs_filter_pid_function_clear(NULL, neg);
+ exit(0);
+ }
+
+ for (; i < argc; i++) {
+ int pid = atoi(argv[i]);
+
+ if (events)
+ tracefs_filter_pid_events(NULL, pid, reset, neg);
+ if (funcs)
+ tracefs_filter_pid_function(NULL, pid, reset, neg);
+
+ reset = false;
+ }
+
+ exit(0);
+}
+
+--
+
+FILES
+-----
+[verse]
+--
+*tracefs.h*
+ Header file to include in order to have access to the library APIs.
+*-ltracefs*
+ Linker switch to add when building a program that uses the library.
+--
+
+SEE ALSO
+--------
+*libtracefs*(3),
+*libtraceevent*(3),
+*trace-cmd*(1),
+*tracefs_hist_alloc*(3),
+*tracefs_hist_alloc_2d*(3),
+*tracefs_hist_alloc_nd*(3),
+*tracefs_hist_free*(3),
+*tracefs_hist_add_key*(3),
+*tracefs_hist_add_value*(3),
+*tracefs_hist_add_name*(3),
+*tracefs_hist_start*(3),
+*tracefs_hist_destory*(3),
+*tracefs_hist_add_sort_key*(3),
+*tracefs_hist_sort_key_direction*(3)
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <rostedt@xxxxxxxxxxx>
+--
+REPORTING BUGS
+--------------
+Report bugs to <linux-trace-devel@xxxxxxxxxxxxxxx>
+
+LICENSE
+-------
+libtracefs is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
+
+COPYING
+-------
+Copyright \(C) 2023 Google, LLC. Free use of this software is granted under
+the terms of the GNU Public License (GPL).
diff --git a/Documentation/libtracefs.txt b/Documentation/libtracefs.txt
index 1962b3b34622..3e73f12de2b5 100644
--- a/Documentation/libtracefs.txt
+++ b/Documentation/libtracefs.txt
@@ -107,6 +107,14 @@ Function filters:
int *tracefs_function_notrace*(struct tracefs_instance pass:[*]_instance_, const char pass:[*]_filter_, const char pass:[*]_module_, int _flags_);
int *tracefs_filter_functions*(const char pass:[*]_filter_, const char pass:[*]_module_, char pass:[*]pass:[*]pass:[*]_list_);
+PID filters:
+ int *tracefs_filter_pid_function*(struct tracefs_instance pass:[*]_instance,_ int _pid_,
+ bool _reset_, bool _notrace_);
+ int *tracefs_filter_pid_function_clear*(struct tracefs_instance pass:[*]_instance_, bool _notrace_);
+ int *tracefs_filter_pid_events*(struct tracefs_instance pass:[*]_instance_, int _pid_,
+ bool _reset_, bool _notrace_);
+ int *tracefs_filter_pid_events_clear*(struct tracefs_instance pass:[*]_instance_, bool _notrace_);
+
Trace helper functions:
void *tracefs_list_free*(char pass:[*]pass:[*]_list_);
char pass:[**]*tracefs_list_add*(char **_list_, const char *_string_);
diff --git a/include/tracefs.h b/include/tracefs.h
index c66bfd2edf0b..d91ab1d943eb 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -269,6 +269,13 @@ enum {
TRACEFS_FL_FUTURE = (1 << 2),
};
+int tracefs_filter_pid_function(struct tracefs_instance *instance, int pid,
+ bool reset, bool notrace);
+int tracefs_filter_pid_function_clear(struct tracefs_instance *instance, bool notrace);
+int tracefs_filter_pid_events(struct tracefs_instance *instance, int pid,
+ bool reset, bool notrace);
+int tracefs_filter_pid_events_clear(struct tracefs_instance *instance, bool notrace);
+
int tracefs_function_filter(struct tracefs_instance *instance, const char *filter,
const char *module, unsigned int flags);
int tracefs_function_notrace(struct tracefs_instance *instance, const char *filter,
diff --git a/src/tracefs-filter.c b/src/tracefs-filter.c
index 3628eaed202f..afe3338c0bd8 100644
--- a/src/tracefs-filter.c
+++ b/src/tracefs-filter.c
@@ -801,6 +801,138 @@ int tracefs_event_filter_clear(struct tracefs_instance *instance,
"filter", "0");
}
+static int write_pid_file(struct tracefs_instance *instance, const char *file,
+ int pid, bool reset)
+{
+ char buf[64];
+ int ret;
+
+ sprintf(buf, "%d", pid);
+
+ if (reset)
+ ret = tracefs_instance_file_write(instance, file, buf);
+ else
+ ret = tracefs_instance_file_append(instance, file, buf);
+
+ return ret < 0 ? -1 : 0;
+}
+
+/**
+ * tracefs_filter_pid_function - set function tracing to filter the pid
+ * @instance: The instance to set the filter to
+ * @pid: The pid to filter on
+ * @reset: If set, it will clear out all other pids being filtered
+ * @notrace: If set, it will filter all but this pid
+ *
+ * Set the function tracing to trace or avoid tracing a given @pid.
+ * If @notrace is set, then it will avoid tracing the @pid.
+ * If @reset is set, it will clear the filter as well.
+ *
+ * Note, @reset only resets what pids will be traced, or what pids will
+ * not be traced. That is, if both @reset and @notrace is set, then
+ * it will not affect pids that are being traced. It will only clear
+ * the pids that are not being traced. To do both, The
+ * tracefs_filter_pid_function_clear() needs to be called with the
+ * inverse of @notrace.
+ *
+ * Returns -1 on error, 0 on success.
+ */
+int tracefs_filter_pid_function(struct tracefs_instance *instance, int pid,
+ bool reset, bool notrace)
+{
+ const char *file;
+
+ if (notrace)
+ file = "set_ftrace_notrace_pid";
+ else
+ file = "set_ftrace_pid";
+
+ return write_pid_file(instance, file, pid, reset);
+}
+
+/**
+ * tracefs_filter_pid_function_clear - reset pid function filtering
+ * @instance: The instance to reset function filtering
+ * @notrace: If set, it will filter reset the pids that are not to be traced
+ *
+ * This will clear the function filtering on pids. If @notrace is set,
+ * it will clear the filtering on what pids should not be traced.
+ *
+ * Returns -1 on error, 0 on success.
+ */
+int tracefs_filter_pid_function_clear(struct tracefs_instance *instance, bool notrace)
+{
+ const char *file;
+ int ret;
+
+ if (notrace)
+ file = "set_ftrace_notrace_pid";
+ else
+ file = "set_ftrace_pid";
+
+ ret = tracefs_instance_file_write(instance, file, "");
+
+ return ret < 0 ? -1 : 0;
+}
+
+/**
+ * tracefs_filter_pid_events - set event filtering to a specific pid
+ * @instance: The instance to set the filter to
+ * @pid: The pid to filter on
+ * @reset: If set, it will clear out all other pids being filtered
+ * @notrace: If set, it will filter all but this pid
+ *
+ * Set the event filtering to trace or avoid tracing a given @pid.
+ * If @notrace is set, then it will avoid tracing the @pid.
+ * If @reset is set, it will clear the filter as well.
+ *
+ * Note, @reset only resets what pids will be traced, or what pids will
+ * not be traced. That is, if both @reset and @notrace is set, then
+ * it will not affect pids that are being traced. It will only clear
+ * the pids that are not being traced. To do both, The
+ * tracefs_filter_pid_events_clear() needs to be called with the
+ * inverse of @notrace.
+ *
+ * Returns -1 on error, 0 on success.
+ */
+int tracefs_filter_pid_events(struct tracefs_instance *instance, int pid,
+ bool reset, bool notrace)
+{
+ const char *file;
+
+ if (notrace)
+ file = "set_event_notrace_pid";
+ else
+ file = "set_event_pid";
+
+ return write_pid_file(instance, file, pid, reset);
+}
+
+/**
+ * tracefs_filter_pid_events_clear - reset pid events filtering
+ * @instance: The instance to reset function filtering
+ * @notrace: If set, it will filter reset the pids that are not to be traced
+ *
+ * This will clear the function filtering on pids. If @notrace is set,
+ * it will clear the filtering on what pids should not be traced.
+ *
+ * Returns -1 on error, 0 on success.
+ */
+int tracefs_filter_pid_events_clear(struct tracefs_instance *instance, bool notrace)
+{
+ const char *file;
+ int ret;
+
+ if (notrace)
+ file = "set_event_notrace_pid";
+ else
+ file = "set_event_pid";
+
+ ret = tracefs_instance_file_write(instance, file, "");
+
+ return ret < 0 ? -1 : 0;
+}
+
/** Deprecated **/
int tracefs_event_append_filter(struct tep_event *event, char **filter,
enum tracefs_filter type,
diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index a94a1f28258a..658e8c149a0f 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -16,12 +16,15 @@
#include <pthread.h>
#include <sys/mount.h>
+#include <sys/syscall.h>
#include <CUnit/CUnit.h>
#include <CUnit/Basic.h>
#include "tracefs.h"
+#define gettid() syscall(__NR_gettid)
+
#define TRACEFS_SUITE "tracefs library"
#define TEST_INSTANCE_NAME "cunit_test_iter"
#define TEST_TRACE_DIR "/tmp/trace_utest.XXXXXX"
@@ -438,6 +441,248 @@ static void test_trace_sql(void)
test_instance_trace_sql(test_instance);
}
+static void call_getppid(int cnt)
+{
+ int i;
+
+ for (i = 0; i < cnt; i++)
+ getppid();
+}
+
+struct check_data {
+ int this_pid;
+ int other_pid;
+ bool trace_this;
+ bool trace_other;
+ bool trace_all;
+ bool hit;
+ int (*filter_clear)(struct tracefs_instance *instance, bool notrace);
+};
+
+static int check_callback(struct tep_event *event, struct tep_record *record,
+ int cpu, void *data)
+{
+ struct check_data *cdata = data;
+ int pid;
+
+ cdata->hit = true;
+
+ pid = tep_data_pid(event->tep, record);
+
+ if (pid == cdata->this_pid) {
+ CU_TEST(cdata->trace_this);
+ return cdata->trace_this ? 0 : -1;
+ }
+
+ if (pid == cdata->other_pid) {
+ CU_TEST(cdata->trace_other);
+ return cdata->trace_other ? 0 : -1;
+ }
+
+ CU_TEST(cdata->trace_all);
+ if (!cdata->trace_all) {
+ printf(" (Traced %d but should not have", pid);
+ if (cdata->trace_this)
+ printf(", this_pid:%d", cdata->this_pid);
+ if (cdata->trace_other)
+ printf(", other_pid:%d", cdata->other_pid);
+ printf(") ");
+ }
+
+ return cdata->trace_all ? 0 : -1;
+}
+
+static int check_filtered_pid(struct tep_handle *tep, struct tracefs_instance *instance,
+ struct check_data *cdata)
+{
+ int ret;
+
+ cdata->hit = false;
+ ret = tracefs_iterate_raw_events(tep, instance, NULL, 0, check_callback, cdata);
+
+ tracefs_instance_clear(instance);
+
+ cdata->filter_clear(instance, false);
+ cdata->filter_clear(instance, true);
+
+ return ret;
+}
+
+struct spin_data {
+ bool stop;
+ bool done;
+ int tid;
+};
+
+static void *trace_spin_thread(void *arg)
+{
+ struct spin_data *data = arg;
+
+ data->tid = gettid();
+ pthread_barrier_wait(&trace_barrier);
+
+ while (!data->done) {
+ pthread_barrier_wait(&trace_barrier);
+ while (!data->stop && !data->done)
+ getppid();
+ pthread_barrier_wait(&trace_barrier);
+ }
+
+ return NULL;
+}
+
+static void run_test(struct tracefs_instance *instance, struct tep_handle *tep,
+ struct spin_data *data, struct check_data *cdata)
+{
+ tracefs_trace_on(instance);
+
+ /* Run a little */
+ call_getppid(1000);
+
+ /* Start the spinner */
+ data->stop = false;
+ pthread_barrier_wait(&trace_barrier);
+
+ /* Allow the other threads run */
+ msleep(100);
+
+ /* Stop the spinners */
+ data->stop = true;
+ pthread_barrier_wait(&trace_barrier);
+ /* Run a little more */
+ call_getppid(10);
+ tracefs_trace_off(instance);
+
+ check_filtered_pid(tep, instance, cdata);
+}
+
+
+static void test_instance_pid_filter(struct tracefs_instance *instance,
+ int (*filter_pid)(struct tracefs_instance *instance,
+ int pid, bool reset, bool notrace),
+ int (*filter_clear)(struct tracefs_instance *instance,
+ bool notrace))
+{
+ struct tep_handle *tep = test_tep;
+ struct check_data cdata;
+ struct spin_data data = { };
+ pthread_t thread1;
+ pthread_t thread2;
+ int this_pid = getpid();
+
+ pthread_barrier_init(&trace_barrier, NULL, 3);
+
+ /* create two spinners, one will be used for tracing */
+ pthread_create(&thread1, NULL, trace_spin_thread, &data);
+ pthread_create(&thread2, NULL, trace_spin_thread, &data);
+
+ pthread_barrier_wait(&trace_barrier);
+
+ cdata.this_pid = this_pid;
+ cdata.other_pid = data.tid;
+ cdata.filter_clear = filter_clear;
+
+ /* Test 1 */
+ cdata.trace_this = true;
+ cdata.trace_other = false;
+ cdata.trace_all = false;
+
+ /* Add the thread, but then reset it out */
+ filter_pid(instance, data.tid, true, false);
+ filter_pid(instance, this_pid, true, false);
+
+ /* Only this thread should be traced */
+ run_test(instance, tep, &data, &cdata);
+ CU_TEST(cdata.hit);
+
+
+ /* Test 2 */
+ cdata.trace_this = true;
+ cdata.trace_other = true;
+ cdata.trace_all = false;
+
+ /* Add the thread, but then reset it out */
+ filter_pid(instance, data.tid, true, false);
+ filter_pid(instance, this_pid, false, false);
+
+ /* Only this thread should be traced */
+ run_test(instance, tep, &data, &cdata);
+ CU_TEST(cdata.hit);
+
+
+ /* Test 3 */
+ cdata.trace_this = false;
+ cdata.trace_other = true;
+ cdata.trace_all = true;
+
+ /* Add the thread, but then reset it out */
+ filter_pid(instance, data.tid, true, true);
+ filter_pid(instance, this_pid, true, true);
+
+ /* Only this thread should be traced */
+ run_test(instance, tep, &data, &cdata);
+ CU_TEST(cdata.hit);
+
+
+ /* Test 4 */
+ cdata.trace_this = false;
+ cdata.trace_other = false;
+ cdata.trace_all = true;
+
+ /* Add the thread, but then reset it out */
+ filter_pid(instance, data.tid, true, true);
+ filter_pid(instance, this_pid, false, true);
+
+ /* Only this thread should be traced */
+ run_test(instance, tep, &data, &cdata);
+ CU_TEST(cdata.hit);
+
+ /* exit out */
+ data.done = true;
+ pthread_barrier_wait(&trace_barrier);
+ pthread_barrier_wait(&trace_barrier);
+
+ pthread_join(thread1, NULL);
+ pthread_join(thread2, NULL);
+}
+
+static void test_function_pid_filter(struct tracefs_instance *instance)
+{
+ tracefs_trace_off(instance);
+ tracefs_instance_clear(instance);
+ tracefs_tracer_set(instance, TRACEFS_TRACER_FUNCTION);
+ test_instance_pid_filter(instance,
+ tracefs_filter_pid_function,
+ tracefs_filter_pid_function_clear);
+ tracefs_tracer_clear(instance);
+ tracefs_trace_on(instance);
+}
+
+static void test_trace_function_pid_filter(void)
+{
+ test_function_pid_filter(NULL);
+ test_function_pid_filter(test_instance);
+}
+
+static void test_events_pid_filter(struct tracefs_instance *instance)
+{
+ tracefs_trace_off(instance);
+ tracefs_instance_clear(instance);
+ tracefs_event_enable(instance, "syscalls", NULL);
+ tracefs_event_enable(instance, "raw_syscalls", NULL);
+ test_instance_pid_filter(instance,
+ tracefs_filter_pid_events,
+ tracefs_filter_pid_events_clear);
+ tracefs_event_disable(instance, NULL, NULL);
+ tracefs_trace_on(instance);
+}
+
+static void test_trace_events_pid_filter(void)
+{
+ test_events_pid_filter(NULL);
+ test_events_pid_filter(test_instance);
+}
+
struct test_cpu_data {
struct tracefs_instance *instance;
struct tracefs_cpu *tcpu;
@@ -593,14 +838,6 @@ static void reset_trace_cpu(struct test_cpu_data *data, bool nonblock)
CU_TEST(data->tcpu != NULL);
}
-static void call_getppid(int cnt)
-{
- int i;
-
- for (i = 0; i < cnt; i++)
- getppid();
-}
-
static void test_cpu_read(struct test_cpu_data *data, int expect)
{
struct tracefs_cpu *tcpu = data->tcpu;
@@ -2965,6 +3202,10 @@ void test_tracefs_lib(void)
test_trace_cpu_read_buf_percent);
CU_add_test(suite, "trace cpu pipe",
test_trace_cpu_pipe);
+ CU_add_test(suite, "trace pid events filter",
+ test_trace_events_pid_filter);
+ CU_add_test(suite, "trace pid function filter",
+ test_trace_function_pid_filter);
CU_add_test(suite, "trace sql",
test_trace_sql);
CU_add_test(suite, "tracing file / directory APIs",
--
2.42.0
|