lib/sysfs: fix semantics of blkdev_is_hotpluggable

This is now decoubled from the kernels notion of a removable *block*
device and instead uses removable kobjects.
This is the correct semantic for hotpluggable devices.

diff --git a/lib/sysfs.c b/lib/sysfs.c
index 838b9af140f5926c14ad08ec347bd31b5aa10f3d..3c2027d994058d71a5da233142c5fbe4212cd17a 100644 (file)
--- a/lib/sysfs.c
+++ b/lib/sysfs.c
@@ -440,47 +440,67 @@ int sysfs_blkdev_next_subsystem(struct path_cxt *pc __attribute__((unused)),
        return 1;
 }
 
+#define REMOVABLE_FILENAME     "/removable"
 
-static int is_hotpluggable_subsystem(const char *name)
+/*
+ * For example:
+ *
+ * chain: /sys/dev/block/../../devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.2/ \
+ *                           1-1.2:1.0/host65/target65:0:0/65:0:0:0/block/sdb
+ */
+static int sysfs_devchain_is_removable(char *chain)
 {
-       static const char * const hotplug_subsystems[] = {
-               "usb",
-               "ieee1394",
-               "pcmcia",
-               "mmc",
-               "ccw"
-       };
-       size_t i;
-
-       for (i = 0; i < ARRAY_SIZE(hotplug_subsystems); i++)
-               if (strcmp(name, hotplug_subsystems[i]) == 0)
-                       return 1;
+       size_t len;
+       char buf[20];
+       char *p;
+
+       if (!chain || !*chain)
+               return 0;
+
+       len = strlen(chain);
+       if (len + sizeof(REMOVABLE_FILENAME) > PATH_MAX)
+               return 0;
+
+       do {
+               int fd, rc;
+
+               /* append "/removable" to the path */
+               memcpy(chain + len, REMOVABLE_FILENAME, sizeof(REMOVABLE_FILENAME));
+
+               /* try to read it */
+               fd = open(chain, O_RDONLY);
+               if (fd != -1) {
+                       rc = read_all(fd, buf, sizeof(buf));
+                       close(fd);
+
+                       if (rc > 0) {
+                               if (strncmp(buf, "fixed", min(rc, 5)) == 0) {
+                                       return 0;
+                               } else if (strncmp(buf, "removable", min(rc, 9)) == 0) {
+                                       return 1;
+                               }
+                       }
+               }
+
+               /* remove last subsystem from chain */
+               chain[len] = '\0';
+               p = strrchr(chain, '/');
+               if (p) {
+                       *p = '\0';
+                       len = p - chain;
+               }
+
+       } while (p);
 
        return 0;
 }
 
 int sysfs_blkdev_is_hotpluggable(struct path_cxt *pc)
 {
-       char buf[PATH_MAX], *chain, *sub;
-       int rc = 0;
-
-
-       /* check /sys/devices/.../removable attribute */
-       if (ul_path_read_s32(pc, &rc, "removable") == 0 && rc == 1)
-               return 1;
+       char buf[PATH_MAX], *chain;
 
        chain = sysfs_blkdev_get_devchain(pc, buf, sizeof(buf));
-
-       while (chain && sysfs_blkdev_next_subsystem(pc, chain, &sub) == 0) {
-               rc = is_hotpluggable_subsystem(sub);
-               if (rc) {
-                       free(sub);
-                       break;
-               }
-               free(sub);
-       }
-
-       return rc;
+       return sysfs_devchain_is_removable(chain);
 }
 
 int sysfs_blkdev_is_removable(struct path_cxt *pc)