trace-cmd: Add ability to add options to trace.dat

Add tracecmd_add_option that allows us to add options into the
trace.dat file. Currently, options may only be added before
the file has been written.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 73 insertions, 4 deletions

diff --git a/trace-output.c b/trace-output.c
index 14fe0f1..d9d1845 100644
--- a/trace-output.c
+++ b/trace-output.c
@@ -39,12 +39,21 @@
 #include "trace-cmd-local.h"
 #include "version.h"
 
+struct tracecmd_option {
+        unsigned short  id;
+        int             size;
+        void            *data;
+};
+
 struct tracecmd_output {
         int             fd;
         int             page_size;
         int             cpus;
         struct pevent   *pevent;
         char            *tracing_dir;
+        int             options_written;
+        int             nr_options;
+        struct tracecmd_option *options;
 };
 
 static int
@@ -72,6 +81,8 @@ static unsigned long long convert_endian_8(struct tracecmd_output *handle,
 
 void tracecmd_output_close(struct tracecmd_output *handle)
 {
+        int i;
+
         if (!handle)
                 return;
 
@@ -86,6 +97,12 @@ void tracecmd_output_close(struct tracecmd_output *handle)
         if (handle->pevent)
                 pevent_unref(handle->pevent);
 
+        if (handle->options) {
+                for (i = 0; i < handle->nr_options; i++)
+                        free(handle->options[i].data);
+                free(handle->options);
+        }
+
         free(handle);
 }
 
@@ -648,23 +665,75 @@ static struct tracecmd_output *create_file(const char *output_file,
         return handle;
 }
 
+/**
+ * tracecmd_add_option - add options to the file
+ * @handle: the output file handle name
+ * @id: the id of the option
+ * @size: the size of the option data
+ * @data: the data to write to the file.
+ */
+int tracecmd_add_option(struct tracecmd_output *handle,
+                        unsigned short id,
+                        int size, void *data)
+{
+        int index = handle->nr_options;
+
+        /*
+         * We can only add options before they were written.
+         * This may change in the future.
+         */
+        if (handle->options_written)
+                return -EBUSY;
+
+        handle->nr_options++;
+
+        if (!handle->options)
+                handle->options = malloc_or_die(sizeof(*handle->options));
+        else {
+                handle->options = realloc(handle->options,
+                                          sizeof(*handle->options) * handle->nr_options);
+                if (!handle->options)
+                        die("Could not reallocate space for options");
+        }
+
+        handle->options[index].id = id;
+        handle->options[index].size = size;
+        handle->options[index].data = malloc_or_die(size);
+        memcpy(handle->options[index].data, data, size);
+
+        return 0;
+}
+
 static int add_options(struct tracecmd_output *handle)
 {
         unsigned short option;
+        int i;
+
+        if (handle->options_written)
+                die("options already written?");
 
         if (do_write_check(handle, "options  ", 10))
                 return -1;
 
-        /*
-         * Right now we have no options, but this is where options
-         * will be added in the future.
-         */
+        for (i = 0; i < handle->nr_options; i++) {
+                if (do_write_check(handle, &handle->options[i].id, 2))
+                        return -1;
+
+                if (do_write_check(handle, &handle->options[i].size, 4))
+                        return -1;
+
+                if (do_write_check(handle, &handle->options[i].data,
+                                   handle->options[i].size))
+                        return -1;
+        }
 
         option = TRACECMD_OPTION_DONE;
 
         if (do_write_check(handle, &option, 2))
                 return -1;
 
+        handle->options_written = 1;
+
         return 0;
 }