busybox 1.21.0: update mdev patch

Update the mdev patch so that subsystem matching is reintroduced.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

1 files changed, 624 insertions, 16 deletions

diff --git a/package/busybox/1.21.0/busybox-1.21.0-mdev.patch b/package/busybox/1.21.0/busybox-1.21.0-mdev.patch
index cb873fafc..8f6c8d80e 100644
--- a/package/busybox/1.21.0/busybox-1.21.0-mdev.patch
+++ b/package/busybox/1.21.0/busybox-1.21.0-mdev.patch
@@ -1,15 +1,429 @@
 --- busybox-1.21.0/util-linux/mdev.c
 +++ busybox-1.21.0-mdev/util-linux/mdev.c
-@@ -661,6 +661,8 @@ static void make_device(char *device_nam
+@@ -80,7 +80,7 @@
+ //usage:	IF_FEATURE_MDEV_CONF(
+ //usage:       "\n"
+ //usage:       "It uses /etc/mdev.conf with lines\n"
+-//usage:       "	[-]DEVNAME UID:GID PERM"
++//usage:       "	[-][ENV=regex;]...DEVNAME UID:GID PERM"
+ //usage:			IF_FEATURE_MDEV_RENAME(" [>|=PATH]|[!]")
+ //usage:			IF_FEATURE_MDEV_EXEC(" [@|$|*PROG]")
+ //usage:       "\n"
+@@ -230,9 +230,34 @@
+  * SUBSYSTEM=block
+  */
+ 
+-static const char keywords[] ALIGN1 = "add\0remove\0change\0";
++#define DEBUG_LVL 2
++
++#if DEBUG_LVL >= 1
++# define dbg1(...) do { if (G.verbose) bb_error_msg(__VA_ARGS__); } while(0)
++#else
++# define dbg1(...) ((void)0)
++#endif
++#if DEBUG_LVL >= 2
++# define dbg2(...) do { if (G.verbose >= 2) bb_error_msg(__VA_ARGS__); } while(0)
++#else
++# define dbg2(...) ((void)0)
++#endif
++#if DEBUG_LVL >= 3
++# define dbg3(...) do { if (G.verbose >= 3) bb_error_msg(__VA_ARGS__); } while(0)
++#else
++# define dbg3(...) ((void)0)
++#endif
++
++
++static const char keywords[] ALIGN1 = "add\0remove\0"; // "change\0"
+ enum { OP_add, OP_remove };
+ 
++struct envmatch {
++	struct envmatch *next;
++	char *envname;
++	regex_t match;
++};
++
+ struct rule {
+ 	bool keep_matching;
+ 	bool regex_compiled;
+@@ -243,12 +268,14 @@ struct rule {
+ 	char *ren_mov;
+ 	IF_FEATURE_MDEV_EXEC(char *r_cmd;)
+ 	regex_t match;
++	struct envmatch *envmatch;
+ };
+ 
+ struct globals {
+ 	int root_major, root_minor;
+ 	smallint verbose;
+ 	char *subsystem;
++	char *subsys_env; /* for putenv("SUBSYSTEM=subsystem") */
+ #if ENABLE_FEATURE_MDEV_CONF
+ 	const char *filename;
+ 	parser_t *parser;
+@@ -256,6 +283,7 @@ struct globals {
+ 	unsigned rule_idx;
+ #endif
+ 	struct rule cur_rule;
++	char timestr[sizeof("60.123456")];
+ } FIX_ALIASING;
+ #define G (*(struct globals*)&bb_common_bufsiz1)
+ #define INIT_G() do { \
+@@ -270,13 +298,6 @@ struct globals {
+ /* We use additional 64+ bytes in make_device() */
+ #define SCRATCH_SIZE 80
+ 
+-#if 0
+-# define dbg(...) bb_error_msg(__VA_ARGS__)
+-#else
+-# define dbg(...) ((void)0)
+-#endif
+-
+-
+ #if ENABLE_FEATURE_MDEV_CONF
+ 
+ static void make_default_cur_rule(void)
+@@ -288,14 +309,65 @@ static void make_default_cur_rule(void)
+ 
+ static void clean_up_cur_rule(void)
+ {
++	struct envmatch *e;
++
+ 	free(G.cur_rule.envvar);
++	free(G.cur_rule.ren_mov);
+ 	if (G.cur_rule.regex_compiled)
+ 		regfree(&G.cur_rule.match);
+-	free(G.cur_rule.ren_mov);
+ 	IF_FEATURE_MDEV_EXEC(free(G.cur_rule.r_cmd);)
++	e = G.cur_rule.envmatch;
++	while (e) {
++		free(e->envname);
++		regfree(&e->match);
++		e = e->next;
++	}
+ 	make_default_cur_rule();
+ }
+ 
++/* In later versions, endofname is in libbb */
++#define endofname mdev_endofname
++static
++const char* FAST_FUNC
++endofname(const char *name)
++{
++#define is_name(c)      ((c) == '_' || isalpha((unsigned char)(c)))
++#define is_in_name(c)   ((c) == '_' || isalnum((unsigned char)(c)))
++	if (!is_name(*name))
++		return name;
++	while (*++name) {
++		if (!is_in_name(*name))
++			break;
++	}
++	return name;
++}
++
++static char *parse_envmatch_pfx(char *val)
++{
++	struct envmatch **nextp = &G.cur_rule.envmatch;
++
++	for (;;) {
++		struct envmatch *e;
++		char *semicolon;
++		char *eq = strchr(val, '=');
++		if (!eq /* || eq == val? */)
++			return val;
++		if (endofname(val) != eq)
++			return val;
++		semicolon = strchr(eq, ';');
++		if (!semicolon)
++			return val;
++		/* ENVVAR=regex;... */
++		*nextp = e = xzalloc(sizeof(*e));
++		nextp = &e->next;
++		e->envname = xstrndup(val, eq - val);
++		*semicolon = '\0';
++		xregcomp(&e->match, eq + 1, REG_EXTENDED);
++		*semicolon = ';';
++		val = semicolon + 1;
++	}
++}
++
+ static void parse_next_rule(void)
+ {
+ 	/* Note: on entry, G.cur_rule is set to default */
+@@ -308,12 +380,13 @@ static void parse_next_rule(void)
+ 			break;
+ 
+ 		/* Fields: [-]regex uid:gid mode [alias] [cmd] */
+-		dbg("token1:'%s'", tokens[1]);
++		dbg3("token1:'%s'", tokens[1]);
+ 
+ 		/* 1st field */
+ 		val = tokens[0];
+ 		G.cur_rule.keep_matching = ('-' == val[0]);
+ 		val += G.cur_rule.keep_matching; /* swallow leading dash */
++		val = parse_envmatch_pfx(val);
+ 		if (val[0] == '@') {
+ 			/* @major,minor[-minor2] */
+ 			/* (useful when name is ambiguous:
+@@ -328,8 +401,10 @@ static void parse_next_rule(void)
+ 			if (sc == 2)
+ 				G.cur_rule.min1 = G.cur_rule.min0;
+ 		} else {
++			char *eq = strchr(val, '=');
+ 			if (val[0] == '$') {
+-				char *eq = strchr(++val, '=');
++				/* $ENVVAR=regex ... */
++				val++;
+ 				if (!eq) {
+ 					bb_error_msg("bad $envvar=regex on line %d", G.parser->lineno);
+ 					goto next_rule;
+@@ -373,7 +448,7 @@ static void parse_next_rule(void)
+ 		clean_up_cur_rule();
+ 	} /* while (config_read) */
+ 
+-	dbg("config_close(G.parser)");
++	dbg3("config_close(G.parser)");
+ 	config_close(G.parser);
+ 	G.parser = NULL;
+ 
+@@ -390,7 +465,7 @@ static const struct rule *next_rule(void
+ 
+ 	/* Open conf file if we didn't do it yet */
+ 	if (!G.parser && G.filename) {
+-		dbg("config_open('%s')", G.filename);
++		dbg3("config_open('%s')", G.filename);
+ 		G.parser = config_open2(G.filename, fopen_for_read);
+ 		G.filename = NULL;
+ 	}
+@@ -399,7 +474,7 @@ static const struct rule *next_rule(void
+ 		/* mdev -s */
+ 		/* Do we have rule parsed already? */
+ 		if (G.rule_vec[G.rule_idx]) {
+-			dbg("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
++			dbg3("< G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
+ 			return G.rule_vec[G.rule_idx++];
+ 		}
+ 		make_default_cur_rule();
+@@ -416,13 +491,28 @@ static const struct rule *next_rule(void
+ 			rule = memcpy(xmalloc(sizeof(G.cur_rule)), &G.cur_rule, sizeof(G.cur_rule));
+ 			G.rule_vec = xrealloc_vector(G.rule_vec, 4, G.rule_idx);
+ 			G.rule_vec[G.rule_idx++] = rule;
+-			dbg("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
++			dbg3("> G.rule_vec[G.rule_idx:%d]=%p", G.rule_idx, G.rule_vec[G.rule_idx]);
+ 		}
+ 	}
+ 
+ 	return rule;
+ }
+ 
++static int env_matches(struct envmatch *e)
++{
++	while (e) {
++		int r;
++		char *val = getenv(e->envname);
++		if (!val)
++			return 0;
++		r = regexec(&e->match, val, /*size*/ 0, /*range[]*/ NULL, /*eflags*/ 0);
++		if (r != 0) /* no match */
++			return 0;
++		e = e->next;
++	}
++	return 1;
++}
++
+ #else
+ 
+ # define next_rule() (&G.cur_rule)
+@@ -479,9 +569,6 @@ static void make_device(char *device_nam
+ {
+ 	int major, minor, type, len;
+ 
+-	if (G.verbose)
+-		bb_error_msg("device: %s, %s", device_name, path);
+-
+ 	/* 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.
+@@ -500,8 +587,7 @@ static void make_device(char *device_nam
+ 			/* no "dev" file, but we can still run scripts
+ 			 * based on device name */
+ 		} else if (sscanf(++dev_maj_min, "%u:%u", &major, &minor) == 2) {
+-			if (G.verbose)
+-				bb_error_msg("maj,min: %u,%u", major, minor);
++			dbg1("dev %u,%u", major, minor);
+ 		} else {
+ 			major = -1;
+ 		}
+@@ -511,7 +597,8 @@ static void make_device(char *device_nam
+ 	/* Determine device name, type, major and minor */
+ 	if (!device_name)
+ 		device_name = (char*) bb_basename(path);
+-	/* http://kernel.org/doc/pending/hotplug.txt says that only
++	/*
++	 * 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.
+@@ -537,6 +624,8 @@ static void make_device(char *device_nam
+ 		rule = next_rule();
+ 
+ #if ENABLE_FEATURE_MDEV_CONF
++		if (!env_matches(rule->envmatch))
++			continue;
+ 		if (rule->maj >= 0) {  /* @maj,min rule */
+ 			if (major != rule->maj)
+ 				continue;
+@@ -547,7 +636,7 @@ static void make_device(char *device_nam
+ 		}
+ 		if (rule->envvar) { /* $envvar=regex rule */
+ 			str_to_match = getenv(rule->envvar);
+-			dbg("getenv('%s'):'%s'", rule->envvar, str_to_match);
++			dbg3("getenv('%s'):'%s'", rule->envvar, str_to_match);
+ 			if (!str_to_match)
+ 				continue;
+ 		}
+@@ -555,7 +644,7 @@ static void make_device(char *device_nam
+ 
+ 		if (rule->regex_compiled) {
+ 			int regex_match = regexec(&rule->match, str_to_match, ARRAY_SIZE(off), off, 0);
+-			dbg("regex_match for '%s':%d", str_to_match, regex_match);
++			dbg3("regex_match for '%s':%d", str_to_match, regex_match);
+ 			//bb_error_msg("matches:");
+ 			//for (int i = 0; i < ARRAY_SIZE(off); i++) {
+ 			//	if (off[i].rm_so < 0) continue;
+@@ -574,9 +663,8 @@ static void make_device(char *device_nam
+ 		}
+ 		/* else: it's final implicit "match-all" rule */
+  rule_matches:
++		dbg2("rule matched, line %d", G.parser ? G.parser->lineno : -1);
+ #endif
+-		dbg("rule matched");
+-
+ 		/* Build alias name */
+ 		alias = NULL;
+ 		if (ENABLE_FEATURE_MDEV_RENAME && rule->ren_mov) {
+@@ -619,34 +707,30 @@ static void make_device(char *device_nam
+ 				}
+ 			}
+ 		}
+-		dbg("alias:'%s'", alias);
++		dbg3("alias:'%s'", alias);
+ 
+ 		command = NULL;
+ 		IF_FEATURE_MDEV_EXEC(command = rule->r_cmd;)
+ 		if (command) {
+-			const char *s = "$@*";
+-			const char *s2 = strchr(s, command[0]);
+-
+ 			/* Are we running this command now?
+-			 * Run $cmd on delete, @cmd on create, *cmd on both
++			 * Run @cmd on create, $cmd on delete, *cmd on any
+ 			 */
+-			if (s2 - s != (operation == OP_remove) || *s2 == '*') {
+-				/* We are here if: '*',
+-				 * or: '@' and delete = 0,
+-				 * or: '$' and delete = 1
+-				 */
++			if ((command[0] == '@' && operation == OP_add)
++			 || (command[0] == '$' && operation == OP_remove)
++			 || (command[0] == '*')
++			) {
+ 				command++;
+ 			} else {
+ 				command = NULL;
+ 			}
+ 		}
+-		dbg("command:'%s'", command);
++		dbg3("command:'%s'", command);
+ 
+ 		/* "Execute" the line we found */
+ 		node_name = device_name;
+ 		if (ENABLE_FEATURE_MDEV_RENAME && alias) {
+ 			node_name = alias = build_alias(alias, device_name);
+-			dbg("alias2:'%s'", alias);
++			dbg3("alias2:'%s'", alias);
+ 		}
+ 
+ 		if (operation == OP_add && major >= 0) {
+@@ -656,8 +740,17 @@ static void make_device(char *device_nam
+ 				mkdir_recursive(node_name);
+ 				*slash = '/';
+ 			}
+-			if (G.verbose)
+-				bb_error_msg("mknod: %s (%d,%d) %o", node_name, major, minor, rule->mode | type);
++			if (ENABLE_FEATURE_MDEV_CONF) {
++				dbg1("mknod %s (%d,%d) %o"
++					" %u:%u",
++					node_name, major, minor, rule->mode | type,
++					rule->ugid.uid, rule->ugid.gid
++				);
++			} else {
++				dbg1("mknod %s (%d,%d) %o",
++					node_name, major, minor, rule->mode | type
++				);
++			}
  			if (mknod(node_name, rule->mode | type, makedev(major, minor)) && errno != EEXIST)
  				bb_perror_msg("can't create '%s'", node_name);
  			if (ENABLE_FEATURE_MDEV_CONF) {
-+				if (G.verbose)
-+					bb_error_msg("chmod: %o chown: %u:%u", rule->mode, rule->ugid.uid, rule->ugid.gid);
- 				chmod(node_name, rule->mode);
- 				chown(node_name, rule->ugid.uid, rule->ugid.gid);
+@@ -671,8 +764,7 @@ static void make_device(char *device_nam
+ //TODO: on devtmpfs, device_name already exists and symlink() fails.
+ //End result is that instead of symlink, we have two nodes.
+ //What should be done?
+-					if (G.verbose)
+-						bb_error_msg("symlink: %s", device_name);
++					dbg1("symlink: %s", device_name);
+ 					symlink(node_name, device_name);
+ 				}
+ 			}
+@@ -681,27 +773,21 @@ static void make_device(char *device_nam
+ 		if (ENABLE_FEATURE_MDEV_EXEC && command) {
+ 			/* setenv will leak memory, use putenv/unsetenv/free */
+ 			char *s = xasprintf("%s=%s", "MDEV", node_name);
+-			char *s1 = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
+ 			putenv(s);
+-			putenv(s1);
+-			if (G.verbose)
+-				bb_error_msg("running: %s", command);
++			dbg1("running: %s", command);
+ 			if (system(command) == -1)
+ 				bb_perror_msg("can't run '%s'", command);
+-			bb_unsetenv_and_free(s1);
+ 			bb_unsetenv_and_free(s);
+ 		}
+ 
+ 		if (operation == OP_remove && major >= -1) {
+ 			if (ENABLE_FEATURE_MDEV_RENAME && alias) {
+ 				if (aliaslink == '>') {
+-					if (G.verbose)
+-						bb_error_msg("unlink: %s", device_name);
++					dbg1("unlink: %s", device_name);
+ 					unlink(device_name);
+ 				}
  			}
-@@ -813,6 +815,7 @@ static void load_firmware(const char *fi
+-			if (G.verbose)
+-				bb_error_msg("unlink: %s", node_name);
++			dbg1("unlink: %s", node_name);
+ 			unlink(node_name);
+ 		}
+ 
+@@ -746,9 +832,16 @@ static int FAST_FUNC dirAction(const cha
+ 	 * under /sys/class/ */
+ 	if (1 == depth) {
+ 		free(G.subsystem);
++		if (G.subsys_env) {
++			bb_unsetenv_and_free(G.subsys_env);
++			G.subsys_env = NULL;
++		}
+ 		G.subsystem = strrchr(fileName, '/');
+-		if (G.subsystem)
++		if (G.subsystem) {
+ 			G.subsystem = xstrdup(G.subsystem + 1);
++			G.subsys_env = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
++			putenv(G.subsys_env);
++		}
+ 	}
+ 
+ 	return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
+@@ -813,12 +906,107 @@ static void load_firmware(const char *fi
  		full_write(loading_fd, "-1", 2);
  
   out:
@@ -17,19 +431,213 @@
  	if (ENABLE_FEATURE_CLEAN_UP) {
  		close(firmware_fd);
  		close(loading_fd);
-@@ -919,11 +922,13 @@ int mdev_main(int argc UNUSED_PARAM, cha
- 		}
+ 	}
+ }
+ 
++static char *curtime(void)
++{
++	struct timeval tv;
++	gettimeofday(&tv, NULL);
++	sprintf(G.timestr, "%u.%06u", (unsigned)tv.tv_sec % 60, (unsigned)tv.tv_usec);
++	return G.timestr;
++}
++
++static void open_mdev_log(const char *seq, unsigned my_pid)
++{
++	int logfd = open("mdev.log", O_WRONLY | O_APPEND);
++	if (logfd >= 0) {
++		xmove_fd(logfd, STDERR_FILENO);
++		G.verbose = 2;
++		applet_name = xasprintf("%s[%s]", applet_name, seq ? seq : utoa(my_pid));
++	}
++}
++
++/* 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.
++ * Active mdev pokes us with SIGCHLD to check the new file.
++ */
++static int
++wait_for_seqfile(const char *seq)
++{
++	/* We time out after 2 sec */
++	static const struct timespec ts = { 0, 32*1000*1000 };
++	int timeout = 2000 / 32;
++	int seq_fd = -1;
++	int do_once = 1;
++	sigset_t set_CHLD;
++
++	sigemptyset(&set_CHLD);
++	sigaddset(&set_CHLD, SIGCHLD);
++	sigprocmask(SIG_BLOCK, &set_CHLD, NULL);
++
++	for (;;) {
++		int seqlen;
++		char seqbuf[sizeof(int)*3 + 2];
++
++		if (seq_fd < 0) {
++			seq_fd = open("mdev.seq", O_RDWR);
++			if (seq_fd < 0)
++				break;
++		}
++		seqlen = pread(seq_fd, seqbuf, sizeof(seqbuf) - 1, 0);
++		if (seqlen < 0) {
++			close(seq_fd);
++			seq_fd = -1;
++			break;
++		}
++		seqbuf[seqlen] = '\0';
++		if (seqbuf[0] == '\n') {
++			/* seed file: write out seq ASAP */
++			xwrite_str(seq_fd, seq);
++			xlseek(seq_fd, 0, SEEK_SET);
++			dbg2("first seq written");
++			break;
++		}
++		if (strcmp(seq, seqbuf) == 0) {
++			/* correct idx */
++			break;
++		}
++		if (do_once) {
++			dbg2("%s waiting for '%s'", curtime(), seqbuf);
++			do_once = 0;
++		}
++		if (sigtimedwait(&set_CHLD, NULL, &ts) >= 0) {
++			dbg3("woken up");
++			continue; /* don't decrement timeout! */
++		}
++		if (--timeout == 0) {
++			dbg1("%s waiting for '%s'", "timed out", seqbuf);
++			break;
++		}
++	}
++	sigprocmask(SIG_UNBLOCK, &set_CHLD, NULL);
++	return seq_fd;
++}
++
++static void signal_mdevs(unsigned my_pid)
++{
++	procps_status_t* p = NULL;
++	while ((p = procps_scan(p, PSSCAN_ARGV0)) != NULL) {
++		if (p->pid != my_pid
++		 && p->argv0
++		 && strcmp(bb_basename(p->argv0), "mdev") == 0
++		) {
++			kill(p->pid, SIGCHLD);
++		}
++	}
++}
++
+ int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+ int mdev_main(int argc UNUSED_PARAM, char **argv)
+ {
+@@ -840,8 +1028,8 @@ int mdev_main(int argc UNUSED_PARAM, cha
+ 	xchdir("/dev");
+ 
+ 	if (argv[1] && strcmp(argv[1], "-s") == 0) {
+-		/* Scan:
+-		 * mdev -s
++		/*
++		 * Scan: mdev -s
+ 		 */
+ 		struct stat st;
+ 
+@@ -853,6 +1041,8 @@ int mdev_main(int argc UNUSED_PARAM, cha
+ 		G.root_major = major(st.st_dev);
+ 		G.root_minor = minor(st.st_dev);
  
- 		{
++		putenv((char*)"ACTION=add");
++
+ 		/* ACTION_FOLLOWLINKS is needed since in newer kernels
+ 		 * /sys/block/loop* (for example) are symlinks to dirs,
+ 		 * not real directories.
+@@ -878,11 +1068,13 @@ int mdev_main(int argc UNUSED_PARAM, cha
+ 		char *action;
+ 		char *env_devname;
+ 		char *env_devpath;
++		unsigned my_pid;
++		int seq_fd;
+ 		smalluint op;
+ 
+ 		/* Hotplug:
+ 		 * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
+-		 * ACTION can be "add" or "remove"
++		 * ACTION can be "add", "remove", "change"
+ 		 * DEVPATH is like "/block/sda" or "/class/input/mice"
+ 		 */
+ 		action = getenv("ACTION");
+@@ -893,39 +1085,20 @@ int mdev_main(int argc UNUSED_PARAM, cha
+ 		if (!action || !env_devpath /*|| !G.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);
+-		}
+ 
+-		{
 -			int logfd = open("/dev/mdev.log", O_WRONLY | O_APPEND);
-+			int logfd = open("mdev.log", O_WRONLY | O_APPEND);
- 			if (logfd >= 0) {
- 				xmove_fd(logfd, STDERR_FILENO);
- 				G.verbose = 1;
+-			if (logfd >= 0) {
+-				xmove_fd(logfd, STDERR_FILENO);
+-				G.verbose = 1;
 -				bb_error_msg("seq: %s action: %s", seq, action);
-+				if (seq)
-+					applet_name = xasprintf("%s[%s]", applet_name, seq);
-+				bb_error_msg("action: %s", action);
+-			}
+-		}
++		my_pid = getpid();
++		open_mdev_log(seq, my_pid);
++
++		seq_fd = seq ? wait_for_seqfile(seq) : -1;
++
++		dbg1("%s "
++			"ACTION:%s SUBSYSTEM:%s DEVNAME:%s DEVPATH:%s"
++			"%s%s",
++			curtime(),
++			action, G.subsystem, env_devname, env_devpath,
++			fw ? " FW:" : "", fw ? fw : ""
++		);
+ 
+ 		snprintf(temp, PATH_MAX, "/sys%s", env_devpath);
+ 		if (op == OP_remove) {
+@@ -935,16 +1108,18 @@ int mdev_main(int argc UNUSED_PARAM, cha
+ 			if (!fw)
+ 				make_device(env_devname, temp, op);
+ 		}
+-		else if (op == OP_add) {
++		else {
+ 			make_device(env_devname, temp, op);
+ 			if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
+-				if (fw)
++				if (op == OP_add && fw)
+ 					load_firmware(fw, temp);
  			}
  		}
  
+-		if (seq) {
+-			xopen_xwrite_close("mdev.seq", utoa(xatou(seq) + 1));
++		dbg1("%s exiting", curtime());
++		if (seq_fd >= 0) {
++			xwrite_str(seq_fd, utoa(xatou(seq) + 1));
++			signal_mdevs(my_pid);
+ 		}
+ 	}
+