1 files changed, 201 insertions, 165 deletions

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 0edaf10..f0a8854 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -12,6 +12,8 @@
 #include "libbb.h"
 #include "xregex.h"
 
+#define ENABLE_FEATURE_MDEV_RENAME_REGEXP 1
+
 struct globals {
 	int root_major, root_minor;
 };
@@ -21,7 +23,21 @@ struct globals {
 
 #define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
 
+/* We use additional 64+ bytes in make_device() */
+#define SCRATCH_SIZE 80
+
+static char *next_field(char *s)
+{
+	char *end = skip_non_whitespace(s);
+	s = skip_whitespace(end);
+	*end = '\0';
+	if (*s == '\0')
+		s = NULL;
+	return s;
+}
+
 /* 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)
 {
 	const char *device_name;
@@ -29,7 +45,7 @@ static void make_device(char *path, int delete)
 	int mode = 0660;
 	uid_t uid = 0;
 	gid_t gid = 0;
-	char *temp = path + strlen(path);
+	char *dev_maj_min = path + strlen(path);
 	char *command = NULL;
 	char *alias = NULL;
 
@@ -42,156 +58,178 @@ static void make_device(char *path, int delete)
 	 * also depend on path having writeable space after it.
 	 */
 	if (!delete) {
-		strcat(path, "/dev");
-		len = open_read_close(path, temp + 1, 64);
-		*temp++ = 0;
+		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)
-				/* no "dev" file, so just try to run script */
-				*temp = 0;
-			else
+			if (!ENABLE_FEATURE_MDEV_EXEC)
 				return;
+			/* no "dev" file, so just try to run script */
+			*dev_maj_min = '\0';
 		}
 	}
 
 	/* Determine device name, type, major and minor */
 	device_name = bb_basename(path);
-	type = (path[5] == 'c' ? S_IFCHR : S_IFBLK);
+	/* http://kernel.org/doc/pending/hotplug.txt says that only
+	 * "/sys/block/..." is for block devices. "sys/bus" etc is not! */
+	type = (strncmp(&path[5], "block/", 6) == 0 ? S_IFBLK : S_IFCHR);
 
 	if (ENABLE_FEATURE_MDEV_CONF) {
 		FILE *fp;
-		char *line, *vline;
+		char *line, *val, *next;
 		unsigned lineno = 0;
 
-		/* If we have a config file, look up the user settings */
+		/* If we have config file, look up 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);
+		while ((line = xmalloc_getline(fp)) != NULL) {
+			regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
 
 			++lineno;
+			trim(line);
+			if (!line[0])
+				goto next_line;
+
+			/* Fields: regex uid:gid mode [alias] [cmd] */
+
+			/* 1st field: regex to match this device */
+			next = next_field(line);
+			{
+				regex_t match;
+				int result;
+
+				/* Is this it? */
+				xregcomp(&match, line, REG_EXTENDED);
+				result = regexec(&match, device_name, 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 || off[0].rm_eo != strlen(device_name))
+					goto next_line;
+			}
 
-			/* Three fields: regex, uid:gid, mode */
-			for (field = 0; field < (3 + ENABLE_FEATURE_MDEV_RENAME + 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);
-
-				} else if (ENABLE_FEATURE_MDEV_RENAME && field == 3) {
-
-					if (*val != '>')
-						++field;
-					else
-						alias = xstrdup(val + 1);
-
-				}
-
-				if (ENABLE_FEATURE_MDEV_EXEC && field == 3 + ENABLE_FEATURE_MDEV_RENAME) {
+			/* This line matches: stop parsing the file
+			 * after parsing the rest of fields */
 
-					/* Optional command to run */
-					const char *s = "@$*";
-					const char *s2 = strchr(s, *val);
+			/* 2nd field: uid:gid - device ownership */
+			if (!next) /* field must exist */
+				bb_error_msg_and_die("bad line %u", lineno);
+			val = next;
+			next = next_field(val);
+			{
+				struct passwd *pass;
+				struct group *grp;
+				char *str_uid = val;
+				char *str_gid = strchrnul(val, ':');
+
+				if (*str_gid)
+					*str_gid++ = '\0';
+				/* 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);
+			}
 
-					if (!s2) {
-						/* Force error */
-						field = 1;
-						break;
+			/* 3rd field: mode - device permissions */
+			if (!next) /* field must exist */
+				bb_error_msg_and_die("bad line %u", lineno);
+			val = next;
+			next = next_field(val);
+			mode = strtoul(val, NULL, 8);
+
+			/* 4th field (opt): >alias */
+			if (ENABLE_FEATURE_MDEV_RENAME) {
+				if (!next)
+					break;
+				if (*next == '>') {
+#if ENABLE_FEATURE_MDEV_RENAME_REGEXP
+					char *s, *p;
+					unsigned i, n;
+#endif
+					val = next;
+					next = next_field(val);
+#if ENABLE_FEATURE_MDEV_RENAME_REGEXP
+					/* substitute %1..9 with off[1..9], if any */
+					n = 0;
+					s = val;
+					while (*s && *s++ == '%')
+						n++;
+
+					p = alias = xzalloc(strlen(val) + n * strlen(device_name));
+					s = val + 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++;
+							}
+						}
+						p++;
+						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));
+#else
+					alias = xstrdup(val + 1);
+#endif
 				}
 			}
 
-			/* Did everything parse happily? */
-			if (field <= 2)
-				bb_error_msg_and_die("bad line %u", lineno);
-
+			/* The rest (opt): command to run */
+			if (!next)
+				break;
+			val = next;
+			if (ENABLE_FEATURE_MDEV_EXEC) {
+				const char *s = "@$*";
+				const char *s2 = strchr(s, *val);
+
+				if (!s2)
+					bb_error_msg_and_die("bad line %u", lineno);
+
+				/* Correlate the position in the "@$*" 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);
+				}
+			}
+			/* end of field parsing */
+			break; /* we found matching line, stop */
  next_line:
 			free(line);
-			if (ENABLE_FEATURE_MDEV_EXEC)
-				free(orig_line);
-		}
-
-		if (ENABLE_FEATURE_CLEAN_UP)
-			fclose(fp);
+		} /* end of "while line is read from /etc/mdev.conf" */
 
- end_parse:	/* nothing */ ;
+		free(line); /* in case we used "break" to get here */
+		fclose(fp);
 	}
+ end_parse:
 
-	if (!delete) {
-		if (sscanf(temp, "%d:%d", &major, &minor) != 2) {
-			if (ENABLE_FEATURE_MDEV_EXEC)
-				goto skip_creation;
-			else
-				return;
-		}
+	if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
 
 		if (ENABLE_FEATURE_MDEV_RENAME)
 			unlink(device_name);
@@ -208,39 +246,44 @@ static void make_device(char *path, int delete)
 			if (ENABLE_FEATURE_MDEV_RENAME && alias) {
 				char *dest;
 
-				temp = strrchr(alias, '/');
-				if (temp) {
-					if (temp[1] != '\0')
-						/* given a file name, so rename it */
-						*temp = '\0';
+				/* ">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 = concat_path_file(alias, device_name);
-				} else
-					dest = alias;
+					*dest = '/';
+					if (dest[1] == '\0') { /* ">bar/" => ">bar/device_name" */
+						dest = alias;
+						alias = concat_path_file(alias, device_name);
+						free(dest);
+					}
+				}
 
-				rename(device_name, dest); // TODO: xrename?
-				symlink(dest, device_name);
+				/* recreate device_name as a symlink to moved device node */
+				if (rename(device_name, alias) == 0) {
+					symlink(alias, device_name);
+				}
 
-				if (alias != dest)
-					free(alias);
-				free(dest);
+				free(alias);
 			}
 		}
- skip_creation: /* nothing */ ;
 	}
+
 	if (ENABLE_FEATURE_MDEV_EXEC && command) {
-		/* setenv will leak memory, so use putenv */
+		/* setenv will leak memory, use putenv/unsetenv/free */
 		char *s = xasprintf("MDEV=%s", device_name);
 		putenv(s);
 		if (system(command) == -1)
-			bb_perror_msg_and_die("cannot run %s", command);
+			bb_perror_msg_and_die("can't run '%s'", command);
 		s[4] = '\0';
 		unsetenv(s);
 		free(s);
 		free(command);
 	}
+
 	if (delete)
-		remove_file(device_name, FILEUTILS_FORCE);
+		unlink(device_name);
 }
 
 /* File callback for /sys/ traversal */
@@ -249,14 +292,15 @@ static int fileAction(const char *fileName,
                       void *userData,
                       int depth ATTRIBUTE_UNUSED)
 {
-	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") || len >= PATH_MAX)
 		return FALSE;
 
 	strcpy(scratch, fileName);
-	scratch[len] = 0;
+	scratch[len] = '\0';
 	make_device(scratch, 0);
 
 	return TRUE;
@@ -287,12 +331,6 @@ 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);
@@ -304,16 +342,15 @@ 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;
 
+ loading:
 	/* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
-	if (write(loading_fd, "1", 1) != 1)
+	if (full_write(loading_fd, "1", 1) != 1)
 		goto out;
 
 	/* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
@@ -324,9 +361,9 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa
 
 	/* 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) {
@@ -341,16 +378,14 @@ int mdev_main(int argc, char **argv)
 {
 	char *action;
 	char *env_path;
-	RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
+	RESERVE_CONFIG_BUFFER(temp, PATH_MAX + SCRATCH_SIZE);
 
 	xchdir("/dev");
 
-	if (argc == 2 && !strcmp(argv[1],"-s")) {
-
+	if (argc == 2 && !strcmp(argv[1], "-s")) {
 		/* Scan:
 		 * mdev -s
 		 */
-
 		struct stat st;
 
 		xstat("/", &st);
@@ -366,26 +401,27 @@ int mdev_main(int argc, char **argv)
 			fileAction, dirAction, temp, 0);
 
 	} else {
-
 		/* Hotplug:
 		 * env ACTION=... DEVPATH=... 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)
 			bb_show_usage();
 
-		sprintf(temp, "/sys%s", env_path);
+		snprintf(temp, PATH_MAX, "/sys%s", env_path);
 		if (!strcmp(action, "remove"))
 			make_device(temp, 1);
 		else if (!strcmp(action, "add")) {
 			make_device(temp, 0);
 
-			if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
-				load_firmware(getenv("FIRMWARE"), temp);
+			if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
+				char *fw = getenv("FIRMWARE");
+				if (fw)
+					load_firmware(fw, temp);
+			}
 		}
 	}