chiark / gitweb /
vol_id: use long options
[elogind.git] / udev_node.c
index 12a738e4e2798fcc1350f4bc7afb8e1e2133e644..b1bbda8369c3e264e86b583015d122e1299f96fe 100644 (file)
@@ -1,8 +1,6 @@
 /*
- * udev-node.c - device node handling
- *
  * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
- * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004-2006 Kay Sievers <kay.sievers@vrfy.org>
  *
  *     This program is free software; you can redistribute it and/or modify it
  *     under the terms of the GNU General Public License as published by the
@@ -15,7 +13,7 @@
  * 
  *     You should have received a copy of the GNU General Public License along
  *     with this program; if not, write to the Free Software Foundation, Inc.,
- *     675 Mass Ave, Cambridge, MA 02139, USA.
+ *     51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  *
  */
 
@@ -27,6 +25,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <grp.h>
+#include <dirent.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -45,13 +44,13 @@ int udev_node_mknod(struct udevice *udev, const char *file, dev_t devt, mode_t m
        else
                mode |= S_IFCHR;
 
-       if (stat(file, &stats) != 0)
+       if (lstat(file, &stats) != 0)
                goto create;
 
        /* preserve node with already correct numbers, to prevent changing the inode number */
        if ((stats.st_mode & S_IFMT) == (mode & S_IFMT) && (stats.st_rdev == devt)) {
                info("preserve file '%s', because it has correct dev_t", file);
-               selinux_setfilecon(file, udev->dev->kernel_name, stats.st_mode);
+               selinux_setfilecon(file, udev->dev->kernel, stats.st_mode);
                goto perms;
        }
 
@@ -61,7 +60,7 @@ int udev_node_mknod(struct udevice *udev, const char *file, dev_t devt, mode_t m
                dbg("already present file '%s' unlinked", file);
 
 create:
-       selinux_setfscreatecon(file, udev->dev->kernel_name, mode);
+       selinux_setfscreatecon(file, udev->dev->kernel, mode);
        retval = mknod(file, mode, devt);
        selinux_resetfscreatecon();
        if (retval != 0) {
@@ -90,52 +89,193 @@ exit:
        return retval;
 }
 
-static int udev_node_symlink(struct udevice *udev, const char *linktarget, const char *filename)
+static int node_symlink(const char *node, const char *slink)
 {
-       char target[PATH_SIZE];
+       char target[PATH_SIZE] = "";
+       char buf[PATH_SIZE];
+       int i = 0;
+       int tail = 0;
        int len;
 
+       /* use relative link */
+       while (node[i] && (node[i] == slink[i])) {
+               if (node[i] == '/')
+                       tail = i+1;
+               i++;
+       }
+       while (slink[i] != '\0') {
+               if (slink[i] == '/')
+                       strlcat(target, "../", sizeof(target));
+               i++;
+       }
+       strlcat(target, &node[tail], sizeof(target));
+
        /* look if symlink already exists */
-       len = readlink(filename, target, sizeof(target));
+       len = readlink(slink, buf, sizeof(buf));
        if (len > 0) {
-               target[len] = '\0';
-               if (strcmp(linktarget, target) == 0) {
-                       info("preserving symlink '%s' to '%s'", filename, linktarget);
-                       selinux_setfilecon(filename, NULL, S_IFLNK);
+               buf[len] = '\0';
+               if (strcmp(target, buf) == 0) {
+                       info("preserve already existing symlink '%s' to '%s'", slink, target);
+                       selinux_setfilecon(slink, NULL, S_IFLNK);
                        goto exit;
-               } else {
-                       info("link '%s' points to different target '%s', delete it", filename, target);
-                       unlink(filename);
                }
+               info("link '%s' points to different target '%s', delete it", slink, buf);
+               unlink(slink);
        }
 
        /* create link */
-       info("creating symlink '%s' to '%s'", filename, linktarget);
-       selinux_setfscreatecon(filename, NULL, S_IFLNK);
-       if (symlink(linktarget, filename) != 0)
-               err("symlink(%s, %s) failed: %s", linktarget, filename, strerror(errno));
+       info("creating symlink '%s' to '%s'", slink, target);
+       selinux_setfscreatecon(slink, NULL, S_IFLNK);
+       if (symlink(target, slink) != 0)
+               err("symlink(%s, %s) failed: %s", target, slink, strerror(errno));
        selinux_resetfscreatecon();
 
 exit:
        return 0;
 }
 
-int udev_node_add(struct udevice *udev, struct udevice *udev_old)
+static int update_link(struct udevice *udev, const char *name)
+{
+       LIST_HEAD(name_list);
+       char slink[PATH_SIZE];
+       char node[PATH_SIZE];
+       struct udevice *udev_db;
+       struct name_entry *device;
+       char target[PATH_MAX] = "";
+       int count;
+       int priority = 0;
+       int rc = 0;
+
+       strlcpy(slink, udev_root, sizeof(slink));
+       strlcat(slink, "/", sizeof(slink));
+       strlcat(slink, name, sizeof(slink));
+
+       count = udev_db_get_devices_by_name(name, &name_list);
+       info("found %i devices with name '%s'", count, name);
+
+       /* if we don't have a reference, delete it */
+       if (count <= 0) {
+               info("no reference left, remove '%s'", name);
+               if (!udev->test_run) {
+                       unlink(slink);
+                       delete_path(slink);
+               }
+               goto out;
+       }
+
+       /* find the device with the highest priority */
+       list_for_each_entry(device, &name_list, node) {
+               info("found '%s' for '%s'", device->name, name);
+
+               /* did we find ourself? we win, if we have the same priority */
+               if (strcmp(udev->dev->devpath, device->name) == 0) {
+                       info("compare (our own) priority of '%s' %i >= %i",
+                            udev->dev->devpath, udev->link_priority, priority);
+                       if (target[0] == '\0' || udev->link_priority >= priority) {
+                               priority = udev->link_priority;
+                               strlcpy(target, udev->name, sizeof(target));
+                       }
+                       continue;
+               }
+
+               /* or something else, then read priority from database */
+               udev_db = udev_device_init(NULL);
+               if (udev_db == NULL)
+                       continue;
+               if (udev_db_get_device(udev_db, device->name) == 0) {
+                       info("compare priority of '%s' %i > %i",
+                            udev_db->dev->devpath, udev_db->link_priority, priority);
+                       if (target[0] == '\0' || udev_db->link_priority > priority) {
+                               priority = udev_db->link_priority;
+                               strlcpy(target, udev_db->name, sizeof(target));
+                       }
+               }
+               udev_device_cleanup(udev_db);
+       }
+       name_list_cleanup(&name_list);
+
+       if (target[0] == '\0') {
+               err("missing target for '%s'", name);
+               rc = -1;
+               goto out;
+       }
+
+       /* create symlink to the target with the highest priority */
+       strlcpy(node, udev_root, sizeof(node));
+       strlcat(node, "/", sizeof(node));
+       strlcat(node, target, sizeof(node));
+       info("'%s' with target '%s' has the highest priority %i, create it", name, target, priority);
+       if (!udev->test_run) {
+               create_path(slink);
+               node_symlink(node, slink);
+       }
+out:
+       return rc;
+}
+
+void udev_node_update_symlinks(struct udevice *udev, struct udevice *udev_old)
 {
-       char filename[PATH_SIZE];
        struct name_entry *name_loop;
+       char symlinks[PATH_SIZE] = "";
+
+       list_for_each_entry(name_loop, &udev->symlink_list, node) {
+               info("update symlink '%s' of '%s'", name_loop->name, udev->dev->devpath);
+               update_link(udev, name_loop->name);
+               strlcat(symlinks, udev_root, sizeof(symlinks));
+               strlcat(symlinks, "/", sizeof(symlinks));
+               strlcat(symlinks, name_loop->name, sizeof(symlinks));
+               strlcat(symlinks, " ", sizeof(symlinks));
+       }
+
+       /* export symlinks to environment */
+       remove_trailing_chars(symlinks, ' ');
+       if (symlinks[0] != '\0')
+               setenv("DEVLINKS", symlinks, 1);
+
+       /* update possible left-over symlinks (device metadata changed) */
+       if (udev_old != NULL) {
+               struct name_entry *link_loop;
+               struct name_entry *link_old_loop;
+               int found;
+
+               /* remove current symlinks from old list */
+               list_for_each_entry(link_old_loop, &udev_old->symlink_list, node) {
+                       found = 0;
+                       list_for_each_entry(link_loop, &udev->symlink_list, node) {
+                               if (strcmp(link_old_loop->name, link_loop->name) == 0) {
+                                       found = 1;
+                                       break;
+                               }
+                       }
+                       if (!found) {
+                               /* link does no longer belong to this device */
+                               info("update old symlink '%s' no longer belonging to '%s'",
+                                    link_old_loop->name, udev->dev->devpath);
+                               update_link(udev, link_old_loop->name);
+                       }
+               }
+
+               /*
+                * if the node name has changed, delete the node,
+                * or possibly restore a symlink of another device
+                */
+               if (strcmp(udev->name, udev_old->name) != 0)
+                       update_link(udev, udev_old->name);
+       }
+}
+
+int udev_node_add(struct udevice *udev)
+{
+       char filename[PATH_SIZE];
        uid_t uid;
        gid_t gid;
-       int tail;
        int i;
        int retval = 0;
 
-       snprintf(filename, sizeof(filename), "%s/%s", udev_root, udev->name);
-       filename[sizeof(filename)-1] = '\0';
-
-       /* create parent directories if needed */
-       if (strchr(udev->name, '/'))
-               create_path(filename);
+       strlcpy(filename, udev_root, sizeof(filename));
+       strlcat(filename, "/", sizeof(filename));
+       strlcat(filename, udev->name, sizeof(filename));
+       create_path(filename);
 
        if (strcmp(udev->owner, "root") == 0)
                uid = 0;
@@ -199,109 +339,21 @@ int udev_node_add(struct udevice *udev, struct udevice *udev_old)
                        }
                }
        }
-
-       /* create symlink(s) if requested */
-       if (!list_empty(&udev->symlink_list)) {
-               char symlinks[512] = "";
-
-               list_for_each_entry(name_loop, &udev->symlink_list, node) {
-                       char linktarget[PATH_SIZE];
-
-                       snprintf(filename, sizeof(filename), "%s/%s", udev_root, name_loop->name);
-                       filename[sizeof(filename)-1] = '\0';
-
-                       dbg("symlink '%s' to node '%s' requested", filename, udev->name);
-                       if (!udev->test_run)
-                               if (strchr(filename, '/'))
-                                       create_path(filename);
-
-                       /* optimize relative link */
-                       linktarget[0] = '\0';
-                       i = 0;
-                       tail = 0;
-                       while (udev->name[i] && (udev->name[i] == name_loop->name[i])) {
-                               if (udev->name[i] == '/')
-                                       tail = i+1;
-                               i++;
-                       }
-                       while (name_loop->name[i] != '\0') {
-                               if (name_loop->name[i] == '/')
-                                       strlcat(linktarget, "../", sizeof(linktarget));
-                               i++;
-                       }
-
-                       strlcat(linktarget, &udev->name[tail], sizeof(linktarget));
-
-                       info("creating symlink '%s' to '%s'", filename, linktarget);
-                       if (!udev->test_run)
-                               udev_node_symlink(udev, linktarget, filename);
-
-                       strlcat(symlinks, filename, sizeof(symlinks));
-                       strlcat(symlinks, " ", sizeof(symlinks));
-               }
-
-               remove_trailing_chars(symlinks, ' ');
-               setenv("DEVLINKS", symlinks, 1);
-       }
-
 exit:
-       selinux_exit();
        return retval;
 }
 
-void udev_node_remove_symlinks(struct udevice *udev)
-{
-       char filename[PATH_SIZE];
-       struct name_entry *name_loop;
-       struct stat stats;
-
-       if (!list_empty(&udev->symlink_list)) {
-               char symlinks[512] = "";
-
-               list_for_each_entry(name_loop, &udev->symlink_list, node) {
-                       snprintf(filename, sizeof(filename), "%s/%s", udev_root, name_loop->name);
-                       filename[sizeof(filename)-1] = '\0';
-
-                       if (stat(filename, &stats) != 0) {
-                               dbg("symlink '%s' not found", filename);
-                               continue;
-                       }
-                       if (udev->devt && stats.st_rdev != udev->devt) {
-                               info("symlink '%s' points to a different device, skip removal", filename);
-                               continue;
-                       }
-
-                       info("removing symlink '%s'", filename);
-                       if (!udev->test_run) {
-                               unlink(filename);
-
-                               if (strchr(filename, '/'))
-                                       delete_path(filename);
-                       }
-
-                       strlcat(symlinks, filename, sizeof(symlinks));
-                       strlcat(symlinks, " ", sizeof(symlinks));
-               }
-
-               remove_trailing_chars(symlinks, ' ');
-               if (symlinks[0] != '\0')
-                       setenv("DEVLINKS", symlinks, 1);
-       }
-}
-
 int udev_node_remove(struct udevice *udev)
 {
        char filename[PATH_SIZE];
        char partitionname[PATH_SIZE];
        struct stat stats;
-       int retval;
+       int retval = 0;
        int num;
 
-       udev_node_remove_symlinks(udev);
-
-       snprintf(filename, sizeof(filename), "%s/%s", udev_root, udev->name);
-       filename[sizeof(filename)-1] = '\0';
-
+       strlcpy(filename, udev_root, sizeof(filename));
+       strlcat(filename, "/", sizeof(filename));
+       strlcat(filename, udev->name, sizeof(filename));
        if (stat(filename, &stats) != 0) {
                dbg("device node '%s' not found", filename);
                return -1;
@@ -312,30 +364,26 @@ int udev_node_remove(struct udevice *udev)
        }
 
        info("removing device node '%s'", filename);
-       retval = unlink_secure(filename);
+       if (!udev->test_run)
+               retval = unlink_secure(filename);
        if (retval)
                return retval;
 
        setenv("DEVNAME", filename, 1);
-
        num = udev->partitions;
        if (num > 0) {
                int i;
 
                info("removing all_partitions '%s[1-%i]'", filename, num);
-               if (num > 255) {
-                       info("garbage from udev database, skip all_partitions removal");
+               if (num > 255)
                        return -1;
-               }
                for (i = 1; i <= num; i++) {
                        snprintf(partitionname, sizeof(partitionname), "%s%d", filename, i);
                        partitionname[sizeof(partitionname)-1] = '\0';
-                       unlink_secure(partitionname);
+                       if (!udev->test_run)
+                               unlink_secure(partitionname);
                }
        }
-
-       if (strchr(udev->name, '/'))
-               delete_path(filename);
-
+       delete_path(filename);
        return retval;
 }