@@ -30,6 +30,10 @@ int tracefs_instance_file_write(struct tracefs_instance *instance,
const char *file, const char *str);
char *tracefs_instance_file_read(struct tracefs_instance *instance,
const char *file, int *psize);
+int tracefs_instance_file_read_number(struct tracefs_instance *instance,
+ const char *file, long long *res);
+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);
bool tracefs_instance_exists(const char *name);
@@ -14,7 +14,7 @@
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
-#include <linux/limits.h>
+#include <limits.h>
#include "tracefs.h"
#include "tracefs-local.h"
@@ -301,6 +301,64 @@ char *tracefs_instance_file_read(struct tracefs_instance *instance,
return buf;
}
+/**
+ * tracefs_instance_file_read_number - Read long long integer from a trace file.
+ * @instance: ftrace instance, can be NULL for the top instance
+ * @file: name of the file
+ * @res: The integer from the file.
+ *
+ * Returns 0 if the reading is successful and the result is stored in res, -1
+ * in case of an error.
+ */
+int tracefs_instance_file_read_number(struct tracefs_instance *instance,
+ const char *file, long long *res)
+{
+ long long num;
+ int ret = -1;
+ int size = 0;
+ char *str;
+
+ str = tracefs_instance_file_read(instance, file, &size);
+ if (size && str) {
+ errno = 0;
+ num = strtoll(str, NULL, 0);
+ if (errno == 0) {
+ *res = num;
+ ret = 0;
+ }
+ }
+ free(str);
+ return ret;
+}
+
+/**
+ * tracefs_instance_file_open - Open a trace file for reading and writing
+ * @instance: ftrace instance, can be NULL for the top instance
+ * @file: name of the file
+ * @mode: file open flags, -1 for default O_RDWR
+ *
+ * Returns -1 in case of an error, or a valid file descriptor otherwise.
+ * The returned FD must be closed with close()
+ */
+int tracefs_instance_file_open(struct tracefs_instance *instance,
+ const char *file, int mode)
+{
+ int flags = O_RDWR;
+ int fd = -1;
+ char *path;
+
+ path = tracefs_instance_get_file(instance, file);
+ if (!path)
+ return -1;
+
+ if (mode >= 0)
+ flags = mode;
+ fd = open(path, flags);
+ tracefs_put_tracing_file(path);
+
+ return fd;
+}
+
static bool check_file_exists(struct tracefs_instance *instance,
char *name, bool dir)
{
These new APIs can be used to read long long integer from frtace file and to open ftrace file: tracefs_instance_file_read_number(); tracefs_instance_file_open(); Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com> --- include/tracefs.h | 4 +++ src/tracefs-instance.c | 60 +++++++++++++++++++++++++++++++++++++++++- 2 files changed, 63 insertions(+), 1 deletion(-)