X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev_node.c;h=0e59e2dbc93cfaefc8249b7cf0c9aea460bd6da3;hp=86fdcd3a419954433b9f0bd4ffbf834996222fca;hb=661a0bea80d129d5df708e36dbaed745c9d8392e;hpb=7ba2d2e6ae70964b68056283fcea209cb4b617ec

diff --git a/udev_node.c b/udev_node.c
index 86fdcd3a4..0e59e2dbc 100644
--- a/udev_node.c
+++ b/udev_node.c
@@ -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>
 
@@ -34,9 +33,11 @@
 #include "udev_rules.h"
 #include "udev_selinux.h"
 
+#define TMP_FILE_EXT		".udev-tmp"
 
 int udev_node_mknod(struct udevice *udev, const char *file, dev_t devt, mode_t mode, uid_t uid, gid_t gid)
 {
+	char file_tmp[PATH_SIZE + sizeof(TMP_FILE_EXT)];
 	struct stat stats;
 	int retval = 0;
 
@@ -45,69 +46,289 @@ 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)
-		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);
-		goto perms;
+	if (lstat(file, &stats) == 0) {
+		if ((stats.st_mode & S_IFMT) == (mode & S_IFMT) && (stats.st_rdev == devt)) {
+			info("preserve file '%s', because it has correct dev_t\n", file);
+			selinux_setfilecon(file, udev->dev->kernel, stats.st_mode);
+			goto perms;
+		}
+	} else {
+		selinux_setfscreatecon(file, udev->dev->kernel, mode);
+		retval = mknod(file, mode, devt);
+		selinux_resetfscreatecon();
+		if (retval == 0)
+			goto perms;
 	}
 
-	if (unlink(file) != 0)
-		err("unlink(%s) failed: %s", file, strerror(errno));
-	else
-		dbg("already present file '%s' unlinked", file);
-
-create:
-	selinux_setfscreatecon(file, udev->dev->kernel_name, mode);
-	retval = mknod(file, mode, devt);
+	info("atomically replace '%s'\n", file);
+	strlcpy(file_tmp, file, sizeof(file_tmp));
+	strlcat(file_tmp, TMP_FILE_EXT, sizeof(file_tmp));
+	unlink(file_tmp);
+	selinux_setfscreatecon(file_tmp, udev->dev->kernel, mode);
+	retval = mknod(file_tmp, mode, devt);
 	selinux_resetfscreatecon();
 	if (retval != 0) {
-		err("mknod(%s, %#o, %u, %u) failed: %s",
-		    file, mode, major(devt), minor(devt), strerror(errno));
+		err("mknod(%s, %#o, %u, %u) failed: %s\n",
+		    file_tmp, mode, major(devt), minor(devt), strerror(errno));
+		goto exit;
+	}
+	retval = rename(file_tmp, file);
+	if (retval != 0) {
+		err("rename(%s, %s) failed: %s\n",
+		    file_tmp, file, strerror(errno));
+		unlink(file_tmp);
 		goto exit;
 	}
 
 perms:
-	dbg("chmod(%s, %#o)", file, mode);
+	dbg("chmod(%s, %#o)\n", file, mode);
 	if (chmod(file, mode) != 0) {
-		err("chmod(%s, %#o) failed: %s", file, mode, strerror(errno));
+		err("chmod(%s, %#o) failed: %s\n", file, mode, strerror(errno));
 		goto exit;
 	}
 
 	if (uid != 0 || gid != 0) {
-		dbg("chown(%s, %u, %u)", file, uid, gid);
+		dbg("chown(%s, %u, %u)\n", file, uid, gid);
 		if (chown(file, uid, gid) != 0) {
-			err("chown(%s, %u, %u) failed: %s",
+			err("chown(%s, %u, %u) failed: %s\n",
 			    file, uid, gid, strerror(errno));
 			goto exit;
 		}
 	}
+exit:
+	return retval;
+}
 
+static int node_symlink(const char *node, const char *slink)
+{
+	struct stat stats;
+	char target[PATH_SIZE] = "";
+	char slink_tmp[PATH_SIZE + sizeof(TMP_FILE_EXT)];
+	int i = 0;
+	int tail = 0;
+	int len;
+	int retval = 0;
+
+	/* 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));
+
+	/* preserve link with correct target, do not replace node of other device */
+	if (lstat(slink, &stats) == 0) {
+		if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
+			struct stat stats2;
+
+			info("found existing node instead of symlink '%s'\n", slink);
+			if (lstat(node, &stats2) == 0) {
+				if ((stats.st_mode & S_IFMT) == (stats2.st_mode & S_IFMT) &&
+				    stats.st_rdev == stats2.st_rdev) {
+					info("replace device node '%s' with symlink to our node '%s'\n", slink, node);
+				} else {
+					err("device node '%s' already exists, link to '%s' will not overwrite it\n", slink, node);
+					goto exit;
+				}
+			}
+		} else if (S_ISLNK(stats.st_mode)) {
+			char buf[PATH_SIZE];
+
+			info("found existing symlink '%s'\n", slink);
+			len = readlink(slink, buf, sizeof(buf));
+			if (len > 0) {
+				buf[len] = '\0';
+				if (strcmp(target, buf) == 0) {
+					info("preserve already existing symlink '%s' to '%s'\n", slink, target);
+					selinux_setfilecon(slink, NULL, S_IFLNK);
+					goto exit;
+				}
+			}
+		}
+	} else {
+		info("creating symlink '%s' to '%s'\n", slink, target);
+		selinux_setfscreatecon(slink, NULL, S_IFLNK);
+		retval = symlink(target, slink);
+		selinux_resetfscreatecon();
+		if (retval == 0)
+			goto exit;
+	}
+
+	info("atomically replace '%s'\n", slink);
+	strlcpy(slink_tmp, slink, sizeof(slink_tmp));
+	strlcat(slink_tmp, TMP_FILE_EXT, sizeof(slink_tmp));
+	unlink(slink_tmp);
+	selinux_setfscreatecon(slink, NULL, S_IFLNK);
+	retval = symlink(target, slink_tmp);
+	selinux_resetfscreatecon();
+	if (retval != 0) {
+		err("symlink(%s, %s) failed: %s\n", target, slink_tmp, strerror(errno));
+		goto exit;
+	}
+	retval = rename(slink_tmp, slink);
+	if (retval != 0) {
+		err("rename(%s, %s) failed: %s\n", slink_tmp, slink, strerror(errno));
+		unlink(slink_tmp);
+		goto exit;
+	}
 exit:
 	return retval;
 }
 
-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'\n", count, name);
+
+	/* if we don't have a reference, delete it */
+	if (count <= 0) {
+		info("no reference left, remove '%s'\n", 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'\n", 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\n",
+			     udev->dev->devpath, udev->link_priority, priority);
+			if (strcmp(udev->name, name) == 0) {
+				info("'%s' is our device node, database inconsistent, skip link update\n", udev->name);
+			} else if (target[0] == '\0' || udev->link_priority >= priority) {
+				priority = udev->link_priority;
+				strlcpy(target, udev->name, sizeof(target));
+			}
+			continue;
+		}
+
+		/* another device, 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) {
+			if (strcmp(udev_db->name, name) == 0) {
+				info("'%s' is a device node of '%s', skip link update\n", udev_db->name, device->name);
+			} else {
+				info("compare priority of '%s' %i > %i\n",
+				     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') {
+		info("no current target for '%s' found\n", 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\n", 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'\n", 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'\n",
+				     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;
 
-	selinux_init();
-
-	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;
@@ -135,7 +356,7 @@ int udev_node_add(struct udevice *udev, struct udevice *udev_old)
 			gid = lookup_group(udev->group);
 	}
 
-	info("creating device node '%s', major = '%d', minor = '%d', " "mode = '%#o', uid = '%d', gid = '%d'",
+	info("creating device node '%s', major=%d, minor=%d, mode=%#o, uid=%d, gid=%d\n",
 	     filename, major(udev->devt), minor(udev->devt), udev->mode, uid, gid);
 
 	if (!udev->test_run)
@@ -154,12 +375,12 @@ int udev_node_add(struct udevice *udev, struct udevice *udev_old)
 
 		/* take the maximum registered minor range */
 		attr = sysfs_attr_get_value(udev->dev->devpath, "range");
-		if (attr) {
+		if (attr != NULL) {
 			range = atoi(attr);
 			if (range > 1)
 				udev->partitions = range-1;
 		}
-		info("creating device partition nodes '%s[1-%i]'", filename, udev->partitions);
+		info("creating device partition nodes '%s[1-%i]'\n", filename, udev->partitions);
 		if (!udev->test_run) {
 			for (i = 1; i <= udev->partitions; i++) {
 				dev_t part_devt;
@@ -171,146 +392,51 @@ 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) {
-				unlink(filename);
-				selinux_setfscreatecon(filename, NULL, S_IFLNK);
-				if (symlink(linktarget, filename) != 0)
-					err("symlink(%s, %s) failed: %s", linktarget, filename, strerror(errno));
-				selinux_resetfscreatecon();
-			}
-
-			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);
-			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;
+		info("device node '%s' not found\n", filename);
+		return 0;
 	}
 	if (udev->devt && stats.st_rdev != udev->devt) {
-		info("device node '%s' points to a different device, skip removal", filename);
+		info("device node '%s' points to a different device, skip removal\n", filename);
 		return -1;
 	}
 
-	info("removing device node '%s'", filename);
-	retval = unlink_secure(filename);
+	info("removing device node '%s'\n", 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");
+		info("removing all_partitions '%s[1-%i]'\n", filename, num);
+		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;
 }