[PATCH] don't sleep if 'dev' file is already present on device add.

instead sleep for up to 10 seconds waiting for it to show up.

diff --git a/udev-add.c b/udev-add.c
index aa93a0c018c25d7610f85753472e2bb63a647b9f..85bcbf6c18212a901f336f58cc1f2708b54fefdc 100644 (file)
--- a/udev-add.c
+++ b/udev-add.c
@@ -34,6 +34,7 @@
 #include "udevdb.h"
 #include "libsysfs/libsysfs.h"
 
+static char sysfs_path[SYSFS_PATH_MAX];
 
 /* 
  * Right now the major/minor of a device is stored in a file called
@@ -101,19 +102,9 @@ static int create_node(char *name, char type, int major, int minor, mode_t mode)
 
 static struct sysfs_class_device *get_class_dev(char *device_name)
 {
-       char sysfs_path[SYSFS_PATH_MAX];
        char dev_path[SYSFS_PATH_MAX];
-       int retval;
        struct sysfs_class_device *class_dev = NULL;
 
-
-       retval = sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX);
-       dbg("sysfs_path = %s", sysfs_path);
-       if (retval) {
-               dbg("sysfs_get_mnt_path failed");
-               goto exit;
-       }
-
        strcpy(dev_path, sysfs_path);
        strcat(dev_path, device_name);
 
@@ -131,6 +122,38 @@ exit:
        return class_dev;
 }
 
+/* wait for the "dev" file to show up in the directory in sysfs.
+ * If it doesn't happen in about 10 seconds, give up.
+ */
+#define SECONDS_TO_WAIT_FOR_DEV                10
+int sleep_for_dev(char *device)
+{
+       char filename[SYSFS_PATH_MAX + 6];
+       struct stat buf;
+       int loop = 0;
+       int retval = -ENODEV;
+
+       strcpy(filename, sysfs_path);
+       strcat(filename, device);
+       strcat(filename, "/dev");
+
+       while (loop < SECONDS_TO_WAIT_FOR_DEV) {
+               dbg("looking for %s", filename);
+               retval = stat(filename, &buf);
+               if (retval == 0) {
+                       retval = 0;
+                       goto exit;
+               }
+
+               /* sleep for a second or two to give the kernel a chance to
+                * create the dev file */
+               sleep(1);
+       }
+       retval = -ENODEV;
+exit:
+       return retval;
+}
+
 int udev_add_device(char *device, char *subsystem)
 {
        struct sysfs_class_device *class_dev;
@@ -146,10 +169,16 @@ int udev_add_device(char *device, char *subsystem)
        else
                type = 'c';
 
-       /* sleep for a second or two to give the kernel a chance to
-        * create the dev file
-        */
-       sleep(1);
+       retval = sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX);
+       dbg("sysfs_path = %s", sysfs_path);
+       if (retval) {
+               dbg("sysfs_get_mnt_path failed");
+               goto exit;
+       }
+
+       retval = sleep_for_dev(device);
+       if (retval)
+               goto exit;
 
        class_dev = get_class_dev(device);
        if (class_dev == NULL)