Getting information on running update

It is often required to inform the operator about the status of the running update and not just to return if the update was successful or not. For example, if the target has a display or a remote interface, it can be forwarded which is reached percentage of the update to let estimate how much the update will still run. SWUpdate has an interface for this (“progress API”). An external process can register itself with SWUpdate, and it will receive notifications when something in the update was changed. This is different from the IPC API, because the last one is mainly used to transfer the SWU image, and it is only possible to poll the interface to know if the update is still running.

API Description

An external process registers itself to SWUpdate with a connect() request to the domain socket “/tmp/swupdateprog” as per default configuration of SWUpdate. There is no information to send, and SWUpdate simply inserts the new connection into the list of processes to be informed. SWUpdate will send a frame back after any change in the update process with the following data (see include/progress_ipc.h):

struct progress_msg {
        unsigned int    magic;          /* Magic Number */
        unsigned int    status;         /* Update Status (Running, Failure) */
        unsigned int    dwl_percent;    /* % downloaded data */
        unsigned int    nsteps;         /* No. total of steps */
        unsigned int    cur_step;       /* Current step index */
        unsigned int    cur_percent;    /* % in current step */
        char            cur_image[256]; /* Name of image to be installed */
        char            hnd_name[64];   /* Name of running handler */
        sourcetype      source;         /* Interface that triggered the update */
        unsigned int    infolen;        /* Len of data valid in info */
        char            info[2048];     /* additional information about install */
};

The single fields have the following meaning:

  • magic is not yet used, it could be added for simply verification of the frame.
  • status is one of the values in swupdate_status.h (START, RUN, SUCCESS, FAILURE, DOWNLOAD, DONE).
  • dwl_percent is the percentage of downloaded data when status = DOWNLOAD.
  • nsteps is the total number of installers (handlers) to be run.
  • cur_step is the index of the running handler. cur_step is in the range 1..nsteps
  • cur_percent is the percentage of work done inside the current handler. This is useful when updating a slow interface, such as a slow flash, and signals which is the percentage of image already copied into the destination.
  • cur_image is the name of the image in sw-description that is currently being installed.
  • hnd_name reports the name of the running handler.
  • source is the interface that triggered the update.
  • infolen length of data in the following info field.
  • info additional information about installation.

As an example for a progress client, tools/progress.c prints the status on the console and drives “psplash” to draw a progress bar on a display.