[PATCH v2 1/3] trace-cruncher: Add methods for accessing tracefs errorlog

* [PATCH v2 1/3] trace-cruncher: Add methods for accessing tracefs errorlog
@ 2021-08-25  9:23 Yordan Karadzhov (VMware)
  2021-08-25  9:23 ` [PATCH v2 2/3] trace-cruncher: Have standard 'not existing' message Yordan Karadzhov (VMware)
  2021-08-25  9:23 ` [PATCH v2 3/3] trace-cruncher: Print the tracefs log on an error Yordan Karadzhov (VMware)
  0 siblings, 2 replies; 3+ messages in thread
From: Yordan Karadzhov (VMware) @ 2021-08-25  9:23 UTC (permalink / raw)
  To: linux-trace-devel; +Cc: Yordan Karadzhov (VMware)

Just wrapping the corresponding APIs of libtracefs.
The functionalities are also available as static methods and will be
used by the module itself when printing the error messages.

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 src/ftracepy-utils.c | 68 ++++++++++++++++++++++++++++++++++++++++++++
 src/ftracepy-utils.h |  6 ++++
 src/ftracepy.c       | 10 +++++++
 3 files changed, 84 insertions(+)

diff --git a/src/ftracepy-utils.c b/src/ftracepy-utils.c
index 581432d..da58855 100644
--- a/src/ftracepy-utils.c
+++ b/src/ftracepy-utils.c
@@ -23,6 +23,38 @@ PyObject *TFS_ERROR;
 PyObject *TEP_ERROR;
 PyObject *TRACECRUNCHER_ERROR;
 
+static const char *get_instance_name(struct tracefs_instance *instance);
+
+static char *tfs_error_log(struct tracefs_instance *instance, bool *ok)
+{;
+	char *err_log;
+
+	errno = 0;
+	err_log = tracefs_error_all(instance);
+	if (errno && !err_log) {
+		PyErr_Format(TFS_ERROR,
+			     "Unable to get error log for instance \'%s\'.",
+		             get_instance_name(instance));
+	}
+
+	if (ok)
+		*ok = errno ? false : true;
+
+	return err_log;
+}
+
+static bool tfs_clear_error_log(struct tracefs_instance *instance)
+{
+	if (tracefs_error_clear(instance) < 0) {
+		PyErr_Format(TFS_ERROR,
+			     "Unable to clear error log for instance \'%s\'.",
+			     get_instance_name(instance));
+		return false;
+	}
+
+	return true;
+}
+
 PyObject *PyTepRecord_time(PyTepRecord* self)
 {
 	unsigned long ts = self->ptrObj ? self->ptrObj->ts : 0;
@@ -2051,6 +2083,42 @@ PyObject *PyFtrace_hook2pid(PyObject *self, PyObject *args, PyObject *kwargs)
 	Py_RETURN_NONE;
 }
 
+PyObject *PyFtrace_error_log(PyObject *self, PyObject *args,
+					     PyObject *kwargs)
+{
+	struct tracefs_instance *instance;
+	PyObject *ret = NULL;
+	char *err_log;
+	bool ok;
+
+	if (!get_instance_from_arg(args, kwargs, &instance))
+		return NULL;
+
+	err_log = tfs_error_log(instance, &ok);
+	if (err_log) {
+		ret = PyUnicode_FromString(err_log);
+		free(err_log);
+	} else if (ok) {
+		ret = PyUnicode_FromString("(nil)");
+	}
+
+	return ret;
+}
+
+PyObject *PyFtrace_clear_error_log(PyObject *self, PyObject *args,
+						   PyObject *kwargs)
+{
+	struct tracefs_instance *instance;
+
+	if (!get_instance_from_arg(args, kwargs, &instance))
+		return NULL;
+
+	if (!tfs_clear_error_log(instance))
+		return NULL;
+
+	Py_RETURN_NONE;
+}
+
 void PyFtrace_at_exit(void)
 {
 }
diff --git a/src/ftracepy-utils.h b/src/ftracepy-utils.h
index 4e04fb0..26a2f14 100644
--- a/src/ftracepy-utils.h
+++ b/src/ftracepy-utils.h
@@ -177,6 +177,12 @@ PyObject *PyFtrace_iterate_trace(PyObject *self, PyObject *args,
 
 PyObject *PyFtrace_hook2pid(PyObject *self, PyObject *args, PyObject *kwargs);
 
+PyObject *PyFtrace_error_log(PyObject *self, PyObject *args,
+					     PyObject *kwargs);
+
+PyObject *PyFtrace_clear_error_log(PyObject *self, PyObject *args,
+						   PyObject *kwargs);
+
 void PyFtrace_at_exit(void);
 
 #endif
diff --git a/src/ftracepy.c b/src/ftracepy.c
index a4fba01..e5a91fc 100644
--- a/src/ftracepy.c
+++ b/src/ftracepy.c
@@ -310,6 +310,16 @@ static PyMethodDef ftracepy_methods[] = {
 	 METH_VARARGS | METH_KEYWORDS,
 	 "Trace only particular process."
 	},
+	{"error_log",
+	 (PyCFunction) PyFtrace_error_log,
+	 METH_VARARGS | METH_KEYWORDS,
+	 "Get the content of the error log."
+	},
+	{"clear_error_log",
+	 (PyCFunction) PyFtrace_clear_error_log,
+	 METH_VARARGS | METH_KEYWORDS,
+	 "Clear the content of the error log."
+	},
 	{NULL, NULL, 0, NULL}
 };
 
-- 
2.30.2


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