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Commit 6cc883ca authored by Benoit Goby's avatar Benoit Goby
Browse files

libusbhost: Fix possible missed "device added" notification 

When a new bus is added, check for existing devices in the bus
directory, since devices may have been added before calling
inotify_add_watch.

Also add missing inotify_rm_watch calls.

Change-Id: Ie69fc995a3e8b18431099b252be86f0054fe5531
parent 35fc46d8

libusbhost/usbhost.c

+43 −20
Original line number Diff line number Diff line
@@ -77,34 +77,48 @@ static inline int badname(const char *name) 
    return 0;

}



/* returns true if one of the callbacks indicates we are done */

static int find_existing_devices(usb_device_added_cb added_cb,

                                  usb_device_removed_cb removed_cb,

static int find_existing_devices_bus(char *busname,

                                     usb_device_added_cb added_cb,

                                     void *client_data)

{

    char busname[32], devname[32];

    DIR *busdir , *devdir ;

    char devname[32];

    DIR *devdir;

    struct dirent *de;

    int done = 0;



    busdir = opendir(USB_FS_DIR);

    if(busdir == 0) return 1;



    while ((de = readdir(busdir)) != 0 && !done) {

        if(badname(de->d_name)) continue;



        snprintf(busname, sizeof busname, "%s/%s", USB_FS_DIR, de->d_name);

    devdir = opendir(busname);

        if(devdir == 0) continue;

    if(devdir == 0) return 0;



    while ((de = readdir(devdir)) && !done) {

        if(badname(de->d_name)) continue;



            snprintf(devname, sizeof devname, "%s/%s", busname, de->d_name);

        snprintf(devname, sizeof(devname), "%s/%s", busname, de->d_name);

        done = added_cb(devname, client_data);

    } // end of devdir while

    closedir(devdir);

    } //end of busdir while



    return done;

}



/* returns true if one of the callbacks indicates we are done */

static int find_existing_devices(usb_device_added_cb added_cb,

                                  void *client_data)

{

    char busname[32];

    DIR *busdir;

    struct dirent *de;

    int done = 0;



    busdir = opendir(USB_FS_DIR);

    if(busdir == 0) return 1;



    while ((de = readdir(busdir)) != 0 && !done) {

        if(badname(de->d_name)) continue;



        snprintf(busname, sizeof(busname), "%s/%s", USB_FS_DIR, de->d_name);

        done = find_existing_devices_bus(busname, added_cb,

                                         client_data);

    }

    closedir(busdir);



    return done;
@@ -167,7 +181,7 @@ void usb_host_run(struct usb_host_context *context, 
    }



    /* check for existing devices first, after we have inotify set up */

    done = find_existing_devices(added_cb, removed_cb, client_data);

    done = find_existing_devices(added_cb, client_data);

    if (discovery_done_cb)

        done |= discovery_done_cb(client_data);
@@ -179,11 +193,20 @@ void usb_host_run(struct usb_host_context *context, 
            if (wd == wds[0]) {

                i = atoi(event->name);

                snprintf(path, sizeof(path), "%s/%s", USB_FS_DIR, event->name);

                D("new subdirectory %s: index: %d\n", path, i);

                D("%s subdirectory %s: index: %d\n", (event->mask & IN_CREATE) ?

                                                     "new" : "gone", path, i);

                if (i > 0 && i < wd_count) {

                ret = inotify_add_watch(context->fd, path, IN_CREATE | IN_DELETE);

                    if (event->mask & IN_CREATE) {

                        ret = inotify_add_watch(context->fd, path,

                                                IN_CREATE | IN_DELETE);

                        if (ret > 0)

                            wds[i] = ret;

                        done = find_existing_devices_bus(path, added_cb,

                                                         client_data);

                    } else if (event->mask & IN_DELETE) {

                        inotify_rm_watch(context->fd, wds[i]);

                        wds[i] = -1;

                    }

                }

            } else {

                for (i = 1; i < wd_count && !done; i++) {