From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Implement tracefs_instances() that will take a regex (or NULL for all) and
return a list of instances in the system.
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
include/tracefs.h | 1 +
src/tracefs-instance.c | 76 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 77 insertions(+)
diff --git a/include/tracefs.h b/include/tracefs.h
index da8ad4189d4d..a21d2d2f22a6 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -44,6 +44,7 @@ int tracefs_instance_file_read_number(struct tracefs_instance *instance,
int tracefs_instance_file_open(struct tracefs_instance *instance,
const char *file, int mode);
int tracefs_instances_walk(int (*callback)(const char *, void *), void *context);
+char **tracefs_instances(const char *regex);
bool tracefs_instance_exists(const char *name);
bool tracefs_file_exists(struct tracefs_instance *instance, const char *name);
diff --git a/src/tracefs-instance.c b/src/tracefs-instance.c
index 2aeb529903bd..ba7667349be2 100644
--- a/src/tracefs-instance.c
+++ b/src/tracefs-instance.c
@@ -14,6 +14,7 @@
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
+#include <regex.h>
#include <limits.h>
#include <pthread.h>
#include "tracefs.h"
@@ -630,6 +631,81 @@ out:
return fret;
}
+static inline bool match(const char *str, regex_t *re)
+{
+ if (!re)
+ return true;
+ return regexec(re, str, 0, NULL, 0) == 0;
+}
+
+struct instance_list {
+ regex_t *re;
+ char **list;
+ int size;
+ int failed;
+};
+
+static int build_list(const char *name, void *data)
+{
+ struct instance_list *list = data;
+ char **instances;
+ int ret = -1;
+
+ if (!match(name, list->re))
+ return 0;
+
+ instances = realloc(list->list, sizeof(*instances) * (list->size + 2));
+ if (!instances)
+ goto out;
+
+ list->list = instances;
+ instances[list->size] = strdup(name);
+ if (!instances[list->size])
+ goto out;
+
+ list->size++;
+ instances[list->size] = NULL;
+ ret = 0;
+
+ out:
+ list->failed = ret;
+ return ret;
+}
+
+/**
+ * tracefs_instances - return a list of instance names
+ * @regex: A regex of instances to filter on (NULL to match all)
+ *
+ * Returns a list of names of existing instances, that must be
+ * freed with tracefs_list_free(). Note, if there are no matches
+ * then an empty list will be returned (not NULL).
+ * NULL on error.
+ */
+char **tracefs_instances(const char *regex)
+{
+ struct instance_list list = { .re = NULL, .list = NULL };
+ regex_t re;
+ int ret;
+
+ if (regex) {
+ ret = regcomp(&re, regex, REG_ICASE|REG_NOSUB);
+ if (ret < 0)
+ return NULL;
+ list.re = &re;
+ }
+
+ ret = tracefs_instances_walk(build_list, &list);
+ if (ret < 0 || list.failed) {
+ tracefs_list_free(list.list);
+ list.list = NULL;
+ } else {
+ /* No matches should produce an empty list */
+ if (!list.list)
+ list.list = calloc(1, sizeof(*list.list));
+ }
+ return list.list;
+}
+
/**
* tracefs_get_clock - Get the current trace clock
* @instance: ftrace instance, can be NULL for the top instance
--
2.30.2
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