mdev: fix the case when move rule deletes node with name == device_name

Signed-off-by: Jean Wolter <jw5@os.inf.tu-dresden.de>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 43 insertions, 19 deletions

diff --git a/testsuite/mdev.tests b/testsuite/mdev.tests
index a1750076e..912785ece 100755
--- a/testsuite/mdev.tests
+++ b/testsuite/mdev.tests
@@ -162,6 +162,32 @@ brw-r--r-- 1 0 1 8,0 sda
 " \
         "" ""
 
+# continuing to use directory structure from prev test
+rm -rf mdev.testdir/dev/*
+mkdir -p mdev.testdir/sys/class/tty/capi
+echo "191:0" >mdev.testdir/sys/class/tty/capi/dev
+mkdir -p mdev.testdir/sys/class/tty/capi1
+echo "191:1" >mdev.testdir/sys/class/tty/capi1/dev
+mkdir -p mdev.testdir/sys/class/tty/capi20
+echo "191:20" >mdev.testdir/sys/class/tty/capi20/dev
+echo "capi            0:0 0660 =capi20"      >mdev.testdir/etc/mdev.conf
+echo "capi([0-9])     0:0 0660 =capi20.0%1" >>mdev.testdir/etc/mdev.conf
+echo "capi([0-9]*)    0:0 0660 =capi20.%1"  >>mdev.testdir/etc/mdev.conf
+# mdev invocation with DEVPATH=/class/tty/capi20 was deleting /dev/capi20
+testing "move rule does not delete node with name == device_name" \
+        "\
+        env - PATH=$PATH ACTION=add DEVPATH=/class/tty/capi chroot mdev.testdir /mdev 2>&1;
+        env - PATH=$PATH ACTION=add DEVPATH=/class/tty/capi1 chroot mdev.testdir /mdev 2>&1;
+        env - PATH=$PATH ACTION=add DEVPATH=/class/tty/capi20 chroot mdev.testdir /mdev 2>&1;
+        ls -lnR mdev.testdir/dev | $FILTER_LS" \
+"\
+mdev.testdir/dev:
+crw-rw---- 1 0 0 191,0 capi20
+crw-rw---- 1 0 0 191,1 capi20.01
+crw-rw---- 1 0 0 191,20 capi20.20
+" \
+        "" ""
+
 # clean up
 rm -rf mdev.testdir
 
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 7508930f7..c68c0a5e7 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -319,22 +319,20 @@ static void make_device(char *path, int delete)
                 /* "Execute" the line we found */
 
                 if (!delete && major >= 0) {
-                        if (ENABLE_FEATURE_MDEV_RENAME)
-                                unlink(device_name);
-                        if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
-                                bb_perror_msg_and_die("mknod %s", device_name);
+                        char *node_name = (char *)device_name;
+                        if (ENABLE_FEATURE_MDEV_RENAME && alias)
+                                alias = node_name = build_alias(alias, device_name);
+                        if (mknod(node_name, mode | type, makedev(major, minor)) && errno != EEXIST)
+                                bb_perror_msg_and_die("mknod %s", node_name);
                         if (major == root_major && minor == root_minor)
-                                symlink(device_name, "root");
+                                symlink(node_name, "root");
                         if (ENABLE_FEATURE_MDEV_CONF) {
-                                chmod(device_name, mode);
-                                chown(device_name, ugid.uid, ugid.gid);
+                                chmod(node_name, mode);
+                                chown(node_name, ugid.uid, ugid.gid);
                         }
                         if (ENABLE_FEATURE_MDEV_RENAME && alias) {
-                                alias = build_alias(alias, device_name);
-                                /* move the device, and optionally
-                                 * make a symlink to moved device node */
-                                if (rename(device_name, alias) == 0 && aliaslink == '>')
-                                        symlink(alias, device_name);
+                                if (aliaslink == '>')
+                                        symlink(node_name, device_name);
                                 free(alias);
                         }
                 }
@@ -355,15 +353,15 @@ static void make_device(char *path, int delete)
                 }
 
                 if (delete) {
-                        unlink(device_name);
-                        /* At creation time, device might have been moved
-                         * and a symlink might have been created. Undo that. */
-
+                        char *node_name = (char *)device_name;
                         if (ENABLE_FEATURE_MDEV_RENAME && alias) {
-                                alias = build_alias(alias, device_name);
-                                unlink(alias);
-                                free(alias);
+                                alias = node_name = build_alias(alias, device_name);
+                                if (aliaslink == '>')
+                                        unlink(device_name);
                         }
+                        unlink(node_name);
+                        if (ENABLE_FEATURE_MDEV_RENAME)
+                                free(alias);
                 }
 
                 /* We found matching line.