X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fudev%2Fudev-builtin-path_id.c;h=720f616da5b28b1e26ee1112f93b95a5e1fe8524;hb=19876c9b3de85f3b82dc3b8bbcaf3297b0d51edf;hp=a8559d2dd4118ac89feb03b7db8ef364caa73a0b;hpb=6df831f25ebc9f55cd939f04392dad9237706e45;p=elogind.git

diff --git a/src/udev/udev-builtin-path_id.c b/src/udev/udev-builtin-path_id.c
index a8559d2dd..720f616da 100644
--- a/src/udev/udev-builtin-path_id.c
+++ b/src/udev/udev-builtin-path_id.c
@@ -176,7 +176,7 @@ static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **
                 transportdev = udev_device_get_parent(transportdev);
                 if (transportdev == NULL)
                         return NULL;
-                if (strncmp(udev_device_get_sysname(transportdev), "session", 7) == 0)
+                if (startswith(udev_device_get_sysname(transportdev), "session"))
                         break;
         }
 
@@ -236,7 +236,23 @@ static struct udev_device *handle_scsi_default(struct udev_device *parent, char
         if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
                 return NULL;
 
-        /* rebase host offset to get the local relative number */
+        /*
+         * Rebase host offset to get the local relative number
+         *
+         * Note: This is by definition racy, unreliable and too simple.
+         * Please do not copy this model anywhere. It's just a left-over
+         * from the time we had no idea how things should look like in
+         * the end.
+         *
+         * Making assumptions about a global in-kernel counter and use
+         * that to calculate a local offset is a very broken concept. It
+         * can only work as long as things are in strict order.
+         *
+         * The kernel needs to export the instance/port number of a
+         * controller directly, without the need for rebase magic like
+         * this. Manual driver unbind/bind, parallel hotplug/unplug will
+         * get into the way of this "I hope it works" logic.
+         */
         basenum = -1;
         base = strdup(udev_device_get_syspath(hostdev));
         if (base == NULL)
@@ -260,7 +276,7 @@ static struct udev_device *handle_scsi_default(struct udev_device *parent, char
                         continue;
                 if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
                         continue;
-                if (strncmp(dent->d_name, "host", 4) != 0)
+                if (!startswith(dent->d_name, "host"))
                         continue;
                 i = strtoul(&dent->d_name[4], &rest, 10);
                 if (rest[0] != '\0')
@@ -340,6 +356,20 @@ out:
         return parent;
 }
 
+static struct udev_device *handle_cciss(struct udev_device *parent, char **path)
+{
+        const char *str;
+        unsigned int controller, disk;
+
+        str = udev_device_get_sysname(parent);
+        if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
+                return NULL;
+
+        path_prepend(path, "cciss-disk%u", disk);
+        parent = skip_subsystem(parent, "cciss");
+        return parent;
+}
+
 static void handle_scsi_tape(struct udev_device *dev, char **path)
 {
         const char *name;
@@ -349,9 +379,9 @@ static void handle_scsi_tape(struct udev_device *dev, char **path)
                 return;
 
         name = udev_device_get_sysname(dev);
-        if (strncmp(name, "nst", 3) == 0 && strchr("lma", name[3]) != NULL)
+        if (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
                 path_prepend(path, "nst%c", name[3]);
-        else if (strncmp(name, "st", 2) == 0 && strchr("lma", name[2]) != NULL)
+        else if (startswith(name, "st") && strchr("lma", name[2]) != NULL)
                 path_prepend(path, "st%c", name[2]);
 }
 
@@ -407,6 +437,7 @@ static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool
 {
         struct udev_device *parent;
         char *path = NULL;
+        bool some_transport = false;
 
         /* S390 ccw bus */
         parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
@@ -427,8 +458,13 @@ static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool
                         handle_scsi_tape(parent, &path);
                 } else if (strcmp(subsys, "scsi") == 0) {
                         parent = handle_scsi(parent, &path);
+                        some_transport = true;
+                } else if (strcmp(subsys, "cciss") == 0) {
+                        parent = handle_cciss(parent, &path);
+                        some_transport = true;
                 } else if (strcmp(subsys, "usb") == 0) {
                         parent = handle_usb(parent, &path);
+                        some_transport = true;
                 } else if (strcmp(subsys, "serio") == 0) {
                         path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
                         parent = skip_subsystem(parent, "serio");
@@ -438,6 +474,7 @@ static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool
                 } else if (strcmp(subsys, "platform") == 0) {
                         path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
                         parent = skip_subsystem(parent, "platform");
+                        some_transport = true;
                 } else if (strcmp(subsys, "acpi") == 0) {
                         path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
                         parent = skip_subsystem(parent, "acpi");
@@ -451,6 +488,17 @@ static int builtin_path_id(struct udev_device *dev, int argc, char *argv[], bool
 
                 parent = udev_device_get_parent(parent);
         }
+
+        /*
+         * Do not return a single-parent-device-only for block
+         * devices, they might have entire buses behind it which
+         * do not get unique IDs only by using the parent device.
+         */
+        if (!some_transport && streq(udev_device_get_subsystem(dev), "block")) {
+                free(path);
+                path = NULL;
+        }
+
 out:
         if (path != NULL) {
                 char tag[UTIL_NAME_SIZE];