mdev: do not complain if mdev.conf does not exist;

use #if to prevent gcc from generating dead code
 (sadly, it's more ugly this way)

docs/mdev.txt

@@ -60,18 +60,23 @@ matched, then the default of 0:0 660 is used.  To set your own default, simply
 create your own total match like so:
 	.* 1:1 777
 
-You can rename/relocate device nodes by using the next optional field.
+You can rename/move device nodes by using the next optional field.
-	<device regex> <uid>:<gid> <octal permissions> [>path]
+	<device regex> <uid>:<gid> <octal permissions> [=path]
 So if you want to place the device node into a subdirectory, make sure the path
 has a trailing /.  If you want to rename the device node, just place the name.
-	hda 0:3 660 >drives/
+	hda 0:3 660 =drives/
-This will relocate "hda" into the drives/ subdirectory.
+This will move "hda" into the drives/ subdirectory.
-	hdb 0:3 660 >cdrom
+	hdb 0:3 660 =cdrom
 This will rename "hdb" to "cdrom".
 
+Similarly, ">path" renames/moves the device but it also creates
+a direct symlink /dev/DEVNAME to the renamed/moved device.
+
 If you also enable support for executing your own commands, then the file has
 the format:
-	<device regex> <uid>:<gid> <octal permissions> [<@|$|*> <command>]
+	<device regex> <uid>:<gid> <octal permissions> [=path] [@|$|*<command>]
+    or
+	<device regex> <uid>:<gid> <octal permissions> [>path] [@|$|*<command>]
 The special characters have the meaning:
 	@ Run after creating the device.
 	$ Run before removing the device.

testsuite/mdev.tests

@@ -29,7 +29,6 @@ testing "mdev add /block/sda" \
 	"env - ACTION=add DEVPATH=/block/sda chroot mdev.testdir /mdev 2>&1;
 	ls -ln mdev.testdir/dev | $FILTER_LS" \
 "\
-mdev: /etc/mdev.conf: No such file or directory
 brw-rw---- 1 0 0 8,0 sda
 " \
 	"" ""

util-linux/mdev.c

@@ -25,6 +25,7 @@ struct globals {
 /* We use additional 64+ bytes in make_device() */
 #define SCRATCH_SIZE 80
 
+#if ENABLE_FEATURE_MDEV_RENAME
 /* Builds an alias path.
  * This function potentionally reallocates the alias parameter.
  */
@@ -48,6 +49,7 @@ static char *build_alias(char *alias, const char *device_name)
 
 	return alias;
 }
+#endif
 
 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
 /* NB: "mdev -s" may call us many times, do not leak memory/fds! */
@@ -56,12 +58,20 @@ static void make_device(char *path, int delete)
 	const char *device_name;
 	int major, minor, type, len;
 	int mode = 0660;
+#if ENABLE_FEATURE_MDEV_CONF
 	uid_t uid = 0;
 	gid_t gid = 0;
-	char *dev_maj_min = path + strlen(path);
+	parser_t *parser;
+	char *tokens[5];
+#endif
+#if ENABLE_FEATURE_MDEV_EXEC
 	char *command = NULL;
+#endif
+#if ENABLE_FEATURE_MDEV_RENAME
 	char *alias = NULL;
 	char aliaslink = aliaslink; /* for compiler */
+#endif
+	char *dev_maj_min = path + strlen(path);
 
 	/* Force the configuration file settings exactly. */
 	umask(0);
@@ -93,9 +103,8 @@ static void make_device(char *path, int delete)
 	if (strstr(path, "/block/"))
 	        type = S_IFBLK;
 
-	if (ENABLE_FEATURE_MDEV_CONF) {
+#if ENABLE_FEATURE_MDEV_CONF
-		parser_t *parser = config_open("/etc/mdev.conf");
+	parser = config_open2("/etc/mdev.conf", fopen_for_read);
-		char *tokens[5];
 
 	/* If we have config file, look up user settings */
 	if (!parser)
@@ -208,10 +217,11 @@ static void make_device(char *path, int delete)
 		}
 #endif /* ENABLE_FEATURE_MDEV_RENAME */
 
+#if ENABLE_FEATURE_MDEV_EXEC
 		/* The rest (opt): command to run */
 		if (!val)
 			break;
-			if (ENABLE_FEATURE_MDEV_EXEC) {
+		{
 			const char *s = "@$*";
 			const char *s2 = strchr(s, *val);
 
@@ -228,13 +238,14 @@ static void make_device(char *path, int delete)
 				command = xstrdup(val + 1);
 			}
 		}
+#endif
 		/* end of field parsing */
 		break; /* we found matching line, stop */
 	} /* end of "while line is read from /etc/mdev.conf" */
 
 	config_close(parser);
-	}
  end_parse:
+#endif /* ENABLE_FEATURE_MDEV_CONF */
 
 	if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
 
@@ -247,10 +258,11 @@ static void make_device(char *path, int delete)
 		if (major == root_major && minor == root_minor)
 			symlink(device_name, "root");
 
-		if (ENABLE_FEATURE_MDEV_CONF) {
+#if ENABLE_FEATURE_MDEV_CONF
 		chown(device_name, uid, gid);
 
-			if (ENABLE_FEATURE_MDEV_RENAME && alias) {
+#if ENABLE_FEATURE_MDEV_RENAME
+		if (alias) {
 			alias = build_alias(alias, device_name);
 
 			/* move the device, and optionally
@@ -260,10 +272,12 @@ static void make_device(char *path, int delete)
 
 			free(alias);
 		}
-		}
+#endif
+#endif
 	}
 
-	if (ENABLE_FEATURE_MDEV_EXEC && command) {
+#if ENABLE_FEATURE_MDEV_EXEC
+	if (command) {
 		/* setenv will leak memory, use putenv/unsetenv/free */
 		char *s = xasprintf("MDEV=%s", device_name);
 		putenv(s);
@@ -274,16 +288,19 @@ static void make_device(char *path, int delete)
 		free(s);
 		free(command);
 	}
+#endif
 
 	if (delete) {
 		unlink(device_name);
 		/* At creation time, device might have been moved
 		 * and a symlink might have been created. Undo that. */
-		if (ENABLE_FEATURE_MDEV_RENAME && alias) {
+#if ENABLE_FEATURE_MDEV_RENAME
+		if (alias) {
 			alias = build_alias(alias, device_name);
 			unlink(alias);
 			free(alias);
 		}
+#endif
 	}
 }