X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=util-linux%2Fmdev.c;h=2451cca05d893505e451c0c41d18f213e6936813;hb=ea4f0847c3d765a782eb9afe3b0f9fb0659cd1bc;hp=65b4da4f48e07359304bcefa9e4515372e23fd72;hpb=46ef46aefb800e3865276b99caf88b6c309a841f;p=oweals%2Fbusybox.git

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 65b4da4f4..2451cca05 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -1,6 +1,5 @@
 /* vi: set sw=4 ts=4: */
 /*
- *
  * mdev - Mini udev for busybox
  *
  * Copyright 2005 Rob Landley <rob@landley.net>
@@ -8,214 +7,359 @@
  *
  * Licensed under GPL version 2, see file LICENSE in this tarball for details.
  */
-
 #include "libbb.h"
 #include "xregex.h"
 
 struct globals {
 	int root_major, root_minor;
+	char *subsystem;
 };
 #define G (*(struct globals*)&bb_common_bufsiz1)
 #define root_major (G.root_major)
 #define root_minor (G.root_minor)
+#define subsystem (G.subsystem)
+
+/* Prevent infinite loops in /sys symlinks */
+#define MAX_SYSFS_DEPTH 3
+
+/* 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.
+ */
+static char *build_alias(char *alias, const char *device_name)
+{
+	char *dest;
+
+	/* ">bar/": rename to bar/device_name */
+	/* ">bar[/]baz": rename to bar[/]baz */
+	dest = strrchr(alias, '/');
+	if (dest) { /* ">bar/[baz]" ? */
+		*dest = '\0'; /* mkdir bar */
+		bb_make_directory(alias, 0755, FILEUTILS_RECUR);
+		*dest = '/';
+		if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
+			dest = alias;
+			alias = concat_path_file(alias, device_name);
+			free(dest);
+		}
+	}
 
-#define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
+	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! */
 static void make_device(char *path, int delete)
 {
+#if ENABLE_FEATURE_MDEV_CONF
+	parser_t *parser;
+#endif
 	const char *device_name;
 	int major, minor, type, len;
-	int mode = 0660;
-	uid_t uid = 0;
-	gid_t gid = 0;
-	char *temp = path + strlen(path);
-	char *command = NULL;
+	int mode;
+	char *dev_maj_min = path + strlen(path);
+
+	/* Force the configuration file settings exactly. */
+	umask(0);
 
 	/* Try to read major/minor string.  Note that the kernel puts \n after
 	 * the data, so we don't need to worry about null terminating the string
-	 * because sscanf() will stop at the first nondigit, which \n is.  We
-	 * also depend on path having writeable space after it.
+	 * because sscanf() will stop at the first nondigit, which \n is.
+	 * We also depend on path having writeable space after it.
 	 */
+	major = -1;
 	if (!delete) {
-		strcat(path, "/dev");
-		len = open_read_close(path, temp + 1, 64);
-		*temp++ = 0;
-		if (len < 1)
-			return;
+		strcpy(dev_maj_min, "/dev");
+		len = open_read_close(path, dev_maj_min + 1, 64);
+		*dev_maj_min++ = '\0';
+		if (len < 1) {
+			if (!ENABLE_FEATURE_MDEV_EXEC)
+				return;
+			/* no "dev" file, so just try to run script */
+			*dev_maj_min = '\0';
+		} else if (sscanf(dev_maj_min, "%u:%u", &major, &minor) != 2) {
+			major = -1;
+		}
 	}
 
 	/* Determine device name, type, major and minor */
 	device_name = bb_basename(path);
-	type = (path[5] == 'c' ? S_IFCHR : S_IFBLK);
-
-	if (ENABLE_FEATURE_MDEV_CONF) {
-		FILE *fp;
-		char *line, *vline;
-		unsigned lineno = 0;
-
-		/* If we have a config file, look up the user settings */
-		fp = fopen_or_warn("/etc/mdev.conf", "r");
-		if (!fp)
-			goto end_parse;
-
-		while ((vline = line = xmalloc_getline(fp)) != NULL) {
-			int field;
-
-			/* A pristine copy for command execution. */
-			char *orig_line;
-			if (ENABLE_FEATURE_MDEV_EXEC)
-				orig_line = xstrdup(line);
-
-			++lineno;
-
-			/* Three fields: regex, uid:gid, mode */
-			for (field = 0; field < (3 + ENABLE_FEATURE_MDEV_EXEC); ++field) {
-
-				/* Find a non-empty field */
-				char *val;
-				do {
-					val = strtok(vline, " \t");
-					vline = NULL;
-				} while (val && !*val);
-				if (!val) {
-					if (field)
-						break;
-					else
-						goto next_line;
-				}
-
-				if (field == 0) {
-
-					/* Regex to match this device */
-					regex_t match;
-					regmatch_t off;
-					int result;
-
-					/* Is this it? */
-					xregcomp(&match, val, REG_EXTENDED);
-					result = regexec(&match, device_name, 1, &off, 0);
-					regfree(&match);
-
-					/* If not this device, skip rest of line */
-					if (result || off.rm_so || off.rm_eo != strlen(device_name))
-						goto next_line;
-
-				} else if (field == 1) {
-
-					/* uid:gid device ownership */
-					struct passwd *pass;
-					struct group *grp;
-
-					char *str_uid = val;
-					char *str_gid = strchr(val, ':');
-					if (str_gid)
-						*str_gid = '\0', ++str_gid;
-
-					/* Parse UID */
-					pass = getpwnam(str_uid);
-					if (pass)
-						uid = pass->pw_uid;
-					else
-						uid = strtoul(str_uid, NULL, 10);
-
-					/* parse GID */
-					grp = getgrnam(str_gid);
-					if (grp)
-						gid = grp->gr_gid;
-					else
-						gid = strtoul(str_gid, NULL, 10);
-
-				} else if (field == 2) {
-
-					/* Mode device permissions */
-					mode = strtoul(val, NULL, 8);
+	/* http://kernel.org/doc/pending/hotplug.txt says that only
+	 * "/sys/block/..." is for block devices. "/sys/bus" etc is not.
+	 * But since 2.6.25 block devices are also in /sys/class/block.
+	 * We use strstr("/block/") to forestall future surprises. */
+	type = S_IFCHR;
+	if (strstr(path, "/block/"))
+		type = S_IFBLK;
+
+#if !ENABLE_FEATURE_MDEV_CONF
+	mode = 0660;
+#else
+	/* If we have config file, look up user settings */
+	parser = config_open2("/etc/mdev.conf", fopen_for_read);
+	while (1) {
+		regmatch_t off[1 + 9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
+		int keep_matching;
+		char *val;
+		struct bb_uidgid_t ugid;
+		char *tokens[4];
+# if ENABLE_FEATURE_MDEV_EXEC
+		char *command = NULL;
+# endif
+# if ENABLE_FEATURE_MDEV_RENAME
+		char *alias = NULL;
+		char aliaslink = aliaslink; /* for compiler */
+# endif
+		/* Defaults in case we won't match any line */
+		ugid.uid = ugid.gid = 0;
+		keep_matching = 0;
+		mode = 0660;
+
+		if (!config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)) {
+			/* End of file, create dev node with default params */
+			goto line_matches;
+		}
 
-				} else if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
+		val = tokens[0];
+		keep_matching = ('-' == val[0]);
+		val += keep_matching; /* swallow leading dash */
+
+		/* Fields: regex uid:gid mode [alias] [cmd] */
+
+		/* 1st field: @<numeric maj,min>... */
+		if (val[0] == '@') {
+			/* @major,minor[-last] */
+			/* (useful when name is ambiguous:
+			 * "/sys/class/usb/lp0" and
+			 * "/sys/class/printer/lp0") */
+			int cmaj, cmin0, cmin1, sc;
+			if (major < 0)
+				continue; /* no dev, no match */
+			sc = sscanf(val, "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
+			if (sc < 1 || major != cmaj
+			 || (sc == 2 && minor != cmin0)
+			 || (sc == 3 && (minor < cmin0 || minor > cmin1))
+			) {
+				continue; /* this line doesn't match */
+			}
+		} else { /* ... or regex to match device name */
+			regex_t match;
+			int result;
+			const char *dev_name_or_subsystem = device_name;
+			if ('/' == val[0] && subsystem) {
+				dev_name_or_subsystem = subsystem;
+				val++;
+			}
 
-					/* Optional command to run */
-					const char *s = "@$*";
-					const char *s2 = strchr(s, *val);
+			/* Is this it? */
+			xregcomp(&match, val, REG_EXTENDED);
+			result = regexec(&match, dev_name_or_subsystem, ARRAY_SIZE(off), off, 0);
+			regfree(&match);
+
+			//bb_error_msg("matches:");
+			//for (int i = 0; i < ARRAY_SIZE(off); i++) {
+			//	if (off[i].rm_so < 0) continue;
+			//	bb_error_msg("match %d: '%.*s'\n", i,
+			//		(int)(off[i].rm_eo - off[i].rm_so),
+			//		device_name + off[i].rm_so);
+			//}
+
+			/* If not this device, skip rest of line */
+			/* (regexec returns whole pattern as "range" 0) */
+			if (result || off[0].rm_so
+			 || ((int)off[0].rm_eo != (int)strlen(dev_name_or_subsystem))
+			) {
+				continue; /* this line doesn't match */
+			}
+		}
 
-					if (!s2) {
-						/* Force error */
-						field = 1;
-						break;
+		/* This line matches: stop parsing the file after parsing
+		 * the rest of fields unless keep_matching == 1 */
+
+		/* 2nd field: uid:gid - device ownership */
+		parse_chown_usergroup_or_die(&ugid, tokens[1]);
+
+		/* 3rd field: mode - device permissions */
+		mode = strtoul(tokens[2], NULL, 8);
+
+		val = tokens[3];
+		/* 4th field (opt): >|=alias */
+# if ENABLE_FEATURE_MDEV_RENAME
+		if (!val)
+			goto line_matches;
+		aliaslink = val[0];
+		if (aliaslink == '>' || aliaslink == '=') {
+			char *a, *s, *st;
+#  if ENABLE_FEATURE_MDEV_RENAME_REGEXP
+			char *p;
+			unsigned i, n;
+#  endif
+			a = val;
+			s = strchrnul(val, ' ');
+			st = strchrnul(val, '\t');
+			if (st < s)
+				s = st;
+			val = (s[0] && s[1]) ? s+1 : NULL;
+			s[0] = '\0';
+
+#  if ENABLE_FEATURE_MDEV_RENAME_REGEXP
+			/* substitute %1..9 with off[1..9], if any */
+			n = 0;
+			s = a;
+			while (*s)
+				if (*s++ == '%')
+					n++;
+
+			p = alias = xzalloc(strlen(a) + n * strlen(device_name));
+			s = a + 1;
+			while (*s) {
+				*p = *s;
+				if ('%' == *s) {
+					i = (s[1] - '0');
+					if (i <= 9 && off[i].rm_so >= 0) {
+						n = off[i].rm_eo - off[i].rm_so;
+						strncpy(p, device_name + off[i].rm_so, n);
+						p += n - 1;
+						s++;
 					}
-
-					/* Correlate the position in the "@$*" with the delete
-					 * step so that we get the proper behavior.
-					 */
-					if ((s2 - s + 1) & (1 << delete))
-						command = xstrdup(orig_line + (val + 1 - line));
 				}
+				p++;
+				s++;
 			}
-
-			/* Did everything parse happily? */
-			if (field <= 2)
-				bb_error_msg_and_die("bad line %u", lineno);
-
- next_line:
-			free(line);
-			if (ENABLE_FEATURE_MDEV_EXEC)
-				free(orig_line);
+#  else
+			alias = xstrdup(a + 1);
+#  endif
+		}
+# endif /* ENABLE_FEATURE_MDEV_RENAME */
+
+# if ENABLE_FEATURE_MDEV_EXEC
+		/* The rest (opt): @|$|*command */
+		if (!val)
+			goto line_matches;
+		{
+			const char *s = "@$*";
+			const char *s2 = strchr(s, val[0]);
+
+			if (!s2)
+				bb_error_msg_and_die("bad line %u", parser->lineno);
+
+			/* Correlate the position in the "@$*" with the delete
+			 * step so that we get the proper behavior:
+			 * @cmd: run on create
+			 * $cmd: run on delete
+			 * *cmd: run on both
+			 */
+			if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
+				command = xstrdup(val + 1);
+			}
+		}
+# endif
+		/* End of field parsing */
+ line_matches:
+#endif /* ENABLE_FEATURE_MDEV_CONF */
+
+		/* "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);
+			if (major == root_major && minor == root_minor)
+				symlink(device_name, "root");
+#if ENABLE_FEATURE_MDEV_CONF
+			chown(device_name, ugid.uid, ugid.gid);
+# if ENABLE_FEATURE_MDEV_RENAME
+			if (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);
+				free(alias);
+			}
+# endif
+#endif
+		}
+#if ENABLE_FEATURE_MDEV_EXEC
+		if (command) {
+			/* setenv will leak memory, use putenv/unsetenv/free */
+			char *s = xasprintf("%s=%s", "MDEV", device_name);
+			char *s1 = xasprintf("%s=%s", "SUBSYSTEM", subsystem);
+			putenv(s);
+			putenv(s1);
+			if (system(command) == -1)
+				bb_perror_msg_and_die("can't run '%s'", command);
+			unsetenv("SUBSYSTEM");
+			free(s1);
+			unsetenv("MDEV");
+			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
+			if (alias) {
+				alias = build_alias(alias, device_name);
+				unlink(alias);
+				free(alias);
+			}
+#endif
 		}
 
-		if (ENABLE_FEATURE_CLEAN_UP)
-			fclose(fp);
-
- end_parse:	/* nothing */ ;
-	}
-
-	umask(0);
-	if (!delete) {
-		if (sscanf(temp, "%d:%d", &major, &minor) != 2)
-			return;
-		if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
-			bb_perror_msg_and_die("mknod %s", device_name);
-
-		if (major == root_major && minor == root_minor)
-			symlink(device_name, "root");
+#if ENABLE_FEATURE_MDEV_CONF
+		/* We found matching line.
+		 * Stop unless it was prefixed with '-' */
+		if (!keep_matching)
+			break;
+	} /* end of "while line is read from /etc/mdev.conf" */
 
-		if (ENABLE_FEATURE_MDEV_CONF)
-			chown(device_name, uid, gid);
-	}
-	if (command) {
-		/* setenv will leak memory, so use putenv */
-		char *s = xasprintf("MDEV=%s", device_name);
-		putenv(s);
-		if (system(command) == -1)
-			bb_perror_msg_and_die("cannot run %s", command);
-		s[4] = '\0';
-		unsetenv(s);
-		free(s);
-		free(command);
-	}
-	if (delete)
-		remove_file(device_name, FILEUTILS_FORCE);
+	config_close(parser);
+#endif /* ENABLE_FEATURE_MDEV_CONF */
 }
 
 /* File callback for /sys/ traversal */
-static int fileAction(const char *fileName, struct stat *statbuf,
-                      void *userData, int depth)
+static int FAST_FUNC fileAction(const char *fileName,
+		struct stat *statbuf UNUSED_PARAM,
+		void *userData,
+		int depth UNUSED_PARAM)
 {
-	size_t len = strlen(fileName) - 4;
+	size_t len = strlen(fileName) - 4; /* can't underflow */
 	char *scratch = userData;
 
-	if (strcmp(fileName + len, "/dev"))
+	/* len check is for paranoid reasons */
+	if (strcmp(fileName + len, "/dev") != 0 || len >= PATH_MAX)
 		return FALSE;
 
 	strcpy(scratch, fileName);
-	scratch[len] = 0;
+	scratch[len] = '\0';
 	make_device(scratch, 0);
 
 	return TRUE;
 }
 
 /* Directory callback for /sys/ traversal */
-static int dirAction(const char *fileName, struct stat *statbuf,
-                      void *userData, int depth)
+static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
+		struct stat *statbuf UNUSED_PARAM,
+		void *userData UNUSED_PARAM,
+		int depth)
 {
+	/* Extract device subsystem -- the name of the directory
+	 * under /sys/class/ */
+	if (1 == depth) {
+		free(subsystem);
+		subsystem = strrchr(fileName, '/');
+		if (subsystem)
+			subsystem = xstrdup(subsystem + 1);
+	}
+
 	return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
 }
 
@@ -235,12 +379,6 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa
 	int cnt;
 	int firmware_fd, loading_fd, data_fd;
 
-	/* check for $FIRMWARE from kernel */
-	/* XXX: dont bother: open(NULL) works same as open("no-such-file")
-	 * if (!firmware)
-	 *	return;
-	 */
-
 	/* check for /lib/firmware/$FIRMWARE */
 	xchdir("/lib/firmware");
 	firmware_fd = xopen(firmware, O_RDONLY);
@@ -252,29 +390,28 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa
 	xchdir(sysfs_path);
 	for (cnt = 0; cnt < 30; ++cnt) {
 		loading_fd = open("loading", O_WRONLY);
-		if (loading_fd == -1)
-			sleep(1);
-		else
-			break;
+		if (loading_fd != -1)
+			goto loading;
+		sleep(1);
 	}
-	if (loading_fd == -1)
-		goto out;
+	goto out;
 
-	/* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
-	if (write(loading_fd, "1", 1) != 1)
+ loading:
+	/* tell kernel we're loading by "echo 1 > /sys/$DEVPATH/loading" */
+	if (full_write(loading_fd, "1", 1) != 1)
 		goto out;
 
-	/* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
+	/* load firmware into /sys/$DEVPATH/data */
 	data_fd = open("data", O_WRONLY);
 	if (data_fd == -1)
 		goto out;
 	cnt = bb_copyfd_eof(firmware_fd, data_fd);
 
-	/* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
+	/* tell kernel result by "echo [0|-1] > /sys/$DEVPATH/loading" */
 	if (cnt > 0)
-		write(loading_fd, "0", 1);
+		full_write(loading_fd, "0", 1);
 	else
-		write(loading_fd, "-1", 2);
+		full_write(loading_fd, "-1", 2);
 
  out:
 	if (ENABLE_FEATURE_CLEAN_UP) {
@@ -285,60 +422,122 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa
 }
 
 int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int mdev_main(int argc, char **argv)
+int mdev_main(int argc UNUSED_PARAM, char **argv)
 {
-	char *action;
-	char *env_path;
-	RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
+	RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
+
+	/* We can be called as hotplug helper */
+	/* Kernel cannot provide suitable stdio fds for us, do it ourself */
+#if 1
+	bb_sanitize_stdio();
+#else
+	/* Debug code */
+	/* Replace LOGFILE by other file or device name if you need */
+#define LOGFILE "/dev/console"
+	/* Just making sure fd 0 is not closed,
+	 * we don't really intend to read from it */
+	xmove_fd(xopen("/", O_RDONLY), STDIN_FILENO);
+	xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDOUT_FILENO);
+	xmove_fd(xopen(LOGFILE, O_WRONLY|O_APPEND), STDERR_FILENO);
+#endif
 
 	xchdir("/dev");
 
-	if (argc == 2 && !strcmp(argv[1],"-s")) {
-
+	if (argv[1] && strcmp(argv[1], "-s") == 0) {
 		/* Scan:
 		 * mdev -s
 		 */
-
 		struct stat st;
 
 		xstat("/", &st);
 		root_major = major(st.st_dev);
 		root_minor = minor(st.st_dev);
 
-		recursive_action("/sys/block",
-			ACTION_RECURSE | ACTION_FOLLOWLINKS,
-			fileAction, dirAction, temp, 0);
-
+		/* ACTION_FOLLOWLINKS is needed since in newer kernels
+		 * /sys/block/loop* (for example) are symlinks to dirs,
+		 * not real directories.
+		 * (kernel's CONFIG_SYSFS_DEPRECATED makes them real dirs,
+		 * but we can't enforce that on users)
+		 */
+		if (access("/sys/class/block", F_OK) != 0) {
+			/* Scan obsolete /sys/block only if /sys/class/block
+			 * doesn't exist. Otherwise we'll have dupes.
+			 * Also, do not complain if it doesn't exist.
+			 * Some people configure kernel to have no blockdevs.
+			 */
+			recursive_action("/sys/block",
+				ACTION_RECURSE | ACTION_FOLLOWLINKS | ACTION_QUIET,
+				fileAction, dirAction, temp, 0);
+		}
 		recursive_action("/sys/class",
 			ACTION_RECURSE | ACTION_FOLLOWLINKS,
 			fileAction, dirAction, temp, 0);
-
 	} else {
+		char *fw;
+		char *seq;
+		char *action;
+		char *env_path;
 
 		/* Hotplug:
-		 * env ACTION=... DEVPATH=... mdev
+		 * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
 		 * ACTION can be "add" or "remove"
 		 * DEVPATH is like "/block/sda" or "/class/input/mice"
 		 */
-
 		action = getenv("ACTION");
 		env_path = getenv("DEVPATH");
-		if (!action || !env_path)
+		subsystem = getenv("SUBSYSTEM");
+		if (!action || !env_path /*|| !subsystem*/)
 			bb_show_usage();
+		fw = getenv("FIRMWARE");
+
+		/* If it exists, does /dev/mdev.seq match $SEQNUM?
+		 * If it does not match, earlier mdev is running
+		 * in parallel, and we need to wait */
+		seq = getenv("SEQNUM");
+		if (seq) {
+			int timeout = 2000 / 32; /* 2000 msec */
+			do {
+				int seqlen;
+				char seqbuf[sizeof(int)*3 + 2];
+
+				seqlen = open_read_close("mdev.seq", seqbuf, sizeof(seqbuf-1));
+				if (seqlen < 0) {
+					seq = NULL;
+					break;
+				}
+				seqbuf[seqlen] = '\0';
+				if (seqbuf[0] == '\n' /* seed file? */
+				 || strcmp(seq, seqbuf) == 0 /* correct idx? */
+				) {
+					break;
+				}
+				usleep(32*1000);
+			} while (--timeout);
+		}
 
-		sprintf(temp, "/sys%s", env_path);
-		if (!strcmp(action, "remove"))
-			make_device(temp, 1);
-		else if (!strcmp(action, "add")) {
+		snprintf(temp, PATH_MAX, "/sys%s", env_path);
+		if (strcmp(action, "remove") == 0) {
+			/* Ignoring "remove firmware". It was reported
+			 * to happen and to cause erroneous deletion
+			 * of device nodes. */
+			if (!fw)
+				make_device(temp, 1);
+		}
+		else if (strcmp(action, "add") == 0) {
 			make_device(temp, 0);
+			if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
+				if (fw)
+					load_firmware(fw, temp);
+			}
+		}
 
-			if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
-				load_firmware(getenv("FIRMWARE"), temp);
+		if (seq) {
+			xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
 		}
 	}
 
 	if (ENABLE_FEATURE_CLEAN_UP)
 		RELEASE_CONFIG_BUFFER(temp);
 
-	return 0;
+	return EXIT_SUCCESS;
 }