2 files changed, 59 insertions, 0 deletions

diff --git a/trace-cmd.h b/trace-cmd.h
index 1db7303..7e21bc7 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -133,6 +133,8 @@ struct tracecmd_output *tracecmd_copy(struct tracecmd_input *ihandle,
                                       const char *file);
 int tracecmd_append_cpu_data(struct tracecmd_output *handle,
                              int cpus, char * const *cpu_data_files);
+int tracecmd_attach_cpu_data(char *file, int cpus, char * const *cpu_data_files);
+int tracecmd_attach_cpu_data_fd(int fd, int cpus, char * const *cpu_data_files);
 
 /* --- Reading the Fly Recorder Trace --- */
 
diff --git a/trace-output.c b/trace-output.c
index a45265d..b586846 100644
--- a/trace-output.c
+++ b/trace-output.c
@@ -762,6 +762,63 @@ int tracecmd_append_cpu_data(struct tracecmd_output *handle,
         return -1;
 }
 
+int tracecmd_attach_cpu_data_fd(int fd, int cpus, char * const *cpu_data_files)
+{
+        struct tracecmd_input *ihandle;
+        struct tracecmd_output *handle;
+        struct pevent *pevent;
+        int ret = -1;
+
+        /* Move the file descriptor to the beginning */
+        if (lseek(fd, 0, SEEK_SET) == (off_t)-1)
+                return -1;
+
+        /* get a input handle from this */
+        ihandle = tracecmd_alloc_fd(fd);
+        if (!ihandle)
+                return -1;
+
+        /* move the file descriptor to the end */
+        if (lseek(fd, 0, SEEK_END) == (off_t)-1)
+                goto out_free;
+
+        /* create a partial output handle */
+
+        handle = malloc(sizeof(*handle));
+        if (!handle)
+                return -1;
+        memset(handle, 0, sizeof(*handle));
+
+        handle->fd = fd;
+
+        /* get endian and page size */
+        pevent = tracecmd_get_pevent(ihandle);
+        /* Use the pevent of the ihandle for later writes */
+        handle->pevent = tracecmd_get_pevent(ihandle);
+        pevent_ref(pevent);
+        handle->page_size = tracecmd_page_size(ihandle);
+
+        if (tracecmd_append_cpu_data(handle, cpus, cpu_data_files) < 0)
+                goto out_free;
+
+        ret = 0;
+        tracecmd_output_close(handle);
+ out_free:
+        tracecmd_close(ihandle);
+        return ret;
+}
+
+int tracecmd_attach_cpu_data(char *file, int cpus, char * const *cpu_data_files)
+{
+        int fd;
+
+        fd = open(file, O_RDWR);
+        if (fd < 0)
+                return -1;
+
+        return tracecmd_attach_cpu_data_fd(fd, cpus, cpu_data_files);
+}
+
 struct tracecmd_output *tracecmd_create_file(const char *output_file,
                                              int cpus, char * const *cpu_data_files)
 {