From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Add the function tracefs_kprobe_clear_probe() that will remove a single
kprobe. If the @force parameter is set, it will disable that probe in all
instances (including the top level instance) before removing it.
If the @event parameter is NULL, then it will clear all events that are
defined by the @system parameter. If the @system parameter is NULL,
then it will use the default "kprobes" group.
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
include/tracefs.h | 1 +
src/tracefs-kprobes.c | 123 +++++++++++++++++++++++++++++++++---------
2 files changed, 100 insertions(+), 24 deletions(-)
diff --git a/include/tracefs.h b/include/tracefs.h
index 3b57c596feab..2771fad6d0ef 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -221,4 +221,5 @@ int tracefs_kretprobe_raw(const char *system, const char *event,
const char *addr, const char *format);
char **tracefs_get_kprobes(void);
int tracefs_kprobe_clear_all(bool force);
+int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force);
#endif /* _TRACE_FS_H */
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 1f0eab6eef4e..7ee43896efff 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -204,18 +204,17 @@ static void disable_events(const char *system, const char *event,
return;
}
-/**
- * tracefs_kprobe_clear_all - clear kprobe events
- * @force: Will attempt to disable all kprobe events and clear them
- *
- * Will remove all defined kprobe events. If any of them are enabled,
- * and @force is not set, then it will error with -1 and errno to be
- * EBUSY. If @force is set, then it will attempt to disable all the kprobe
- * events in all instances, and try again.
- *
- * Returns zero on success, -1 otherwise.
- */
-int tracefs_kprobe_clear_all(bool force)
+static int clear_kprobe(const char *system, const char *event)
+{
+ /* '-' + ':' + '/' + '\n' + '\0' = 5 bytes */
+ int len = strlen(system) + strlen(event) + 5;
+ char content[len];
+
+ sprintf(content, "-:%s/%s", system, event);
+ return tracefs_instance_file_append(NULL, KPROBE_EVENTS, content);
+}
+
+static int kprobe_clear_probes(const char *group, bool force)
{
char **instance_list;
char **kprobe_list;
@@ -226,13 +225,6 @@ int tracefs_kprobe_clear_all(bool force)
int ret;
int i;
- ret = tracefs_instance_file_clear(NULL, KPROBE_EVENTS);
- if (!ret)
- return 0;
-
- if (!force)
- return -1;
-
kprobe_list = tracefs_get_kprobes();
if (!kprobe_list)
return -1;
@@ -244,6 +236,13 @@ int tracefs_kprobe_clear_all(bool force)
* top level.
*/
+ /*
+ * If a system is defined, the default is to pass unless
+ * an event fails to be removed. If a system is not defined,
+ * the default is to fail, unless all are removed.
+ */
+ ret = group ? 0 : -1;
+
for (i = 0; kprobe_list[i]; i++) {
kprobe = kprobe_list[i];
@@ -255,15 +254,91 @@ int tracefs_kprobe_clear_all(bool force)
if (!event)
goto out;
- disable_events(system, event, instance_list);
+ /* Skip if this does not match a given system */
+ if (group && strcmp(system, group) != 0)
+ continue;
- ret = tracefs_instance_file_clear(NULL, KPROBE_EVENTS);
- /* On success stop the loop */
- if (!ret)
- goto out;
+ if (force)
+ disable_events(system, event, instance_list);
+
+ if (group) {
+ ret = clear_kprobe(system, event);
+ if (ret < 0)
+ goto out;
+ } else {
+ ret = tracefs_instance_file_clear(NULL, KPROBE_EVENTS);
+ /* On success stop the loop */
+ if (!ret)
+ goto out;
+ }
+
+ /* Set the default for whether a system is defined or not */
+ ret = group ? 0 : -1;
}
out:
tracefs_list_free(instance_list);
tracefs_list_free(kprobe_list);
return ret;
}
+
+/**
+ * tracefs_kprobe_clear_all - clear kprobe events
+ * @force: Will attempt to disable all kprobe events and clear them
+ *
+ * Will remove all defined kprobe events. If any of them are enabled,
+ * and @force is not set, then it will error with -1 and errno to be
+ * EBUSY. If @force is set, then it will attempt to disable all the kprobe
+ * events in all instances, and try again.
+ *
+ * Returns zero on success, -1 otherwise.
+ */
+int tracefs_kprobe_clear_all(bool force)
+{
+ if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0)
+ return 0;
+
+ if (!force)
+ return -1;
+
+ /* Attempt to disable all kprobe events */
+ return kprobe_clear_probes(NULL, force);
+}
+
+/**
+ * tracefs_kprobe_clear_all - clear kprobe events
+ * @system: System to clear (NULL means default)
+ * @event: Name of probe to clear in system (NULL for all probes in system)
+ * @force: Will attempt to disable all kprobe events and clear them
+ *
+ * Will remove the kprobes that match the @system and @event. If @system
+ * is NULL, then "kprobes" is used and will ignore all other system
+ * groups of kprobes. The @event is NULL then all events under the given
+ * @system are removed, otherwise only the event that matches.
+ *
+ * Returns zero on success, -1 otherwise.
+ */
+int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force)
+{
+ char **instance_list;
+ int ret;
+
+ if (!system)
+ system = "kprobes";
+
+ if (!event)
+ return kprobe_clear_probes(system, force);
+
+ /*
+ * Since we know we are disabling a specific event, try
+ * to disable it first before clearing it.
+ */
+ if (force) {
+ instance_list = tracefs_instances(NULL);
+ disable_events(system, event, instance_list);
+ tracefs_list_free(instance_list);
+ }
+
+ ret = clear_kprobe(system, event);
+
+ return ret < 0 ? -1 : 0;
+}
--
2.30.2
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