trace-cmd: Add options to trace.dat file

Add the start of option to the trace.dat file. This will allow
later versions of the file to add data without breaking older
versions of trace-cmd.

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

4 files changed, 77 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index b094abe..6cd9b93 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,7 @@ KS_PATCHLEVEL = 2
 KS_EXTRAVERSION =
 
 # file format version
-FILE_VERSION = 5
+FILE_VERSION = 6
 
 MAKEFLAGS += --no-print-directory
 
diff --git a/trace-cmd.h b/trace-cmd.h
index 7e21bc7..b484998 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -61,6 +61,10 @@ char *tracecmd_find_tracing_dir(void);
 
 /* --- Opening and Reading the trace.dat file --- */
 
+enum {
+        TRACECMD_OPTION_DONE,
+};
+
 struct tracecmd_input *tracecmd_alloc(const char *file);
 struct tracecmd_input *tracecmd_alloc_fd(int fd);
 struct tracecmd_input *tracecmd_open(const char *file);
diff --git a/trace-input.c b/trace-input.c
index fed915d..c919cd0 100644
--- a/trace-input.c
+++ b/trace-input.c
@@ -1747,6 +1747,36 @@ static int init_cpu(struct tracecmd_input *handle, int cpu)
         return 0;
 }
 
+static int handle_options(struct tracecmd_input *handle)
+{
+        unsigned short option;
+        unsigned int size;
+        char *buf;
+
+        do {
+                if (do_read_check(handle, &option, 2))
+                        return -1;
+
+                switch (option) {
+                case TRACECMD_OPTION_DONE:
+                        break;
+                default:
+                        warning("unknown option %d", option);
+                        /* next 4 bytes is the size of the option */
+                        if (do_read_check(handle, &size, 4))
+                                return -1;
+                        size = __data2host4(handle->pevent, size);
+                        buf = malloc_or_die(size);
+                        if (do_read_check(handle, buf, size))
+                                return -1;
+                        free(buf);
+                        break;
+                }
+        } while (option != TRACECMD_OPTION_DONE);
+
+        return 0;
+}
+
 /**
  * tracecmd_init_data - prepare reading the data from trace.dat
  * @handle: input handle for the trace.dat file
@@ -1783,14 +1813,27 @@ int tracecmd_init_data(struct tracecmd_input *handle)
         pevent_set_cpus(pevent, handle->cpus);
         pevent_set_long_size(pevent, handle->long_size);
 
+        if (do_read_check(handle, buf, 10))
+                return -1;
+
+        /* check if this handles options */
+        if (strncmp(buf, "options", 7) == 0) {
+                if (handle_options(handle) < 0)
+                        return -1;
+                if (do_read_check(handle, buf, 10))
+                        return -1;
+        }
+
         /*
          * Check if this is a latency report or not.
          */
-        if (do_read_check(handle, buf, 10))
-                return -1;
         if (strncmp(buf, "latency", 7) == 0)
                 return 1;
 
+        /* We expect this to be flyrecord */
+        if (strncmp(buf, "flyrecord", 9) != 0)
+                return -1;
+
         handle->cpu_data = malloc(sizeof(*handle->cpu_data) * handle->cpus);
         if (!handle->cpu_data)
                 return -1;
diff --git a/trace-output.c b/trace-output.c
index b586846..89b3954 100644
--- a/trace-output.c
+++ b/trace-output.c
@@ -327,7 +327,7 @@ static int copy_event_system(struct tracecmd_output *handle, const char *sys)
         endian4 = convert_endian_4(handle, count);
         if (do_write_check(handle, &endian4, 4))
                 return -1;
-        
+
         rewinddir(dir);
         while ((dent = readdir(dir))) {
                 if (strcmp(dent->d_name, ".") == 0 ||
@@ -648,6 +648,26 @@ static struct tracecmd_output *create_file(const char *output_file, int cpus,
         return handle;
 }
 
+static int add_options(struct tracecmd_output *handle)
+{
+        unsigned short option;
+
+        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.
+         */
+
+        option = TRACECMD_OPTION_DONE;
+
+        if (do_write_check(handle, &option, 2))
+                return -1;
+
+        return 0;
+}
+
 struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus)
 {
         struct tracecmd_output *handle;
@@ -661,6 +681,9 @@ struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, in
         if (do_write_check(handle, &cpus, 4))
                 goto out_free;
 
+        if (add_options(handle) < 0)
+                goto out_free;
+
         if (do_write_check(handle, "latency  ", 10))
                 goto out_free;
 
@@ -697,6 +720,9 @@ int tracecmd_append_cpu_data(struct tracecmd_output *handle,
         if (do_write_check(handle, &endian4, 4))
                 goto out_free;
 
+        if (add_options(handle) < 0)
+                goto out_free;
+
         if (do_write_check(handle, "flyrecord", 10))
                 goto out_free;