X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=util-linux%2Fmdev.c;h=a4c0520ac302179d7ee58a77de0b68b8f8a2cc9e;hb=67075bb95f23233c49628a624cc6ba86c3462dcb;hp=33dc5d38f627b4da4c87952f404cc99e3fdc7656;hpb=6ca409e0e4c198fe3081346eebbae3f068fe605a;p=oweals%2Fbusybox.git

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 33dc5d38f..a4c0520ac 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -19,9 +19,24 @@ struct globals {
 #define root_major (G.root_major)
 #define root_minor (G.root_minor)
 
-#define MAX_SYSFS_DEPTH 3 /* prevent infinite loops in /sys symlinks */
+/* Prevent infinite loops in /sys symlinks */
+#define MAX_SYSFS_DEPTH 3
+
+/* 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;
@@ -29,195 +44,286 @@ 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;
+	char aliaslink = aliaslink; /* for compiler */
+
+	/* 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. */
-
+	 * also depend on path having writeable space after it.
+	 */
 	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';
+		}
 	}
 
 	/* Determine device name, type, major and minor */
-
 	device_name = bb_basename(path);
-	type = path[5]=='c' ? S_IFCHR : S_IFBLK;
-
-	/* If we have a config file, look up permissions for this device */
+	/* http://kernel.org/doc/pending/hotplug.txt says that only
+	 * "/sys/block/..." is for block devices. "/sys/bus" etc is not!
+	 * Since kernel 2.6.25 block devices are also in /sys/class/block. */
+	/* TODO: would it be acceptable to just use strstr(path, "/block/")? */
+	if (strncmp(&path[5], "class/block/"+6, 6) != 0
+	 && strncmp(&path[5], "class/block/", 12) != 0)
+	        type = S_IFCHR;
+	else
+	        type = S_IFBLK;
 
 	if (ENABLE_FEATURE_MDEV_CONF) {
-		char *conf, *pos, *end;
-		int line, fd;
+		FILE *fp;
+		char *line, *val, *next;
+		unsigned lineno = 0;
 
-		/* mmap the config file */
-		fd = open("/etc/mdev.conf", O_RDONLY);
-		if (fd < 0)
-			goto end_parse;
-		len = xlseek(fd, 0, SEEK_END);
-		conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
-		close(fd);
-		if (!conf)
+		/* If we have config file, look up user settings */
+		fp = fopen_or_warn("/etc/mdev.conf", "r");
+		if (!fp)
 			goto end_parse;
 
-		line = 0;
-		/* Loop through lines in mmaped file*/
-		for (pos=conf; pos-conf<len;) {
-			int field;
-			char *end2;
+		while ((line = xmalloc_fgetline(fp)) != NULL) {
+			regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
 
-			line++;
-			/* find end of this line */
-			for (end=pos; end-conf<len && *end!='\n'; end++)
-				;
+			++lineno;
+			trim(line);
+			if (!line[0])
+				goto next_line;
 
-			/* Three fields: regex, uid:gid, mode */
-			for (field=0; field < (3 + ENABLE_FEATURE_MDEV_EXEC);
-					field++)
+			/* Fields: regex uid:gid mode [alias] [cmd] */
+
+			/* 1st field: regex to match this device */
+			next = next_field(line);
 			{
-				/* Skip whitespace */
-				while (pos<end && isspace(*pos)) pos++;
-				if (pos==end || *pos=='#') break;
-				for (end2=pos;
-					end2<end && !isspace(*end2) && *end2!='#'; end2++)
-					;
-
-				if (field == 0) {
-					/* Regex to match this device */
-
-					char *regex = xstrndup(pos, end2-pos);
-					regex_t match;
-					regmatch_t off;
-					int result;
-
-					/* Is this it? */
-					xregcomp(&match,regex, REG_EXTENDED);
-					result = regexec(&match, device_name, 1, &off, 0);
-					regfree(&match);
-					free(regex);
-
-					/* If not this device, skip rest of line */
-					if (result || off.rm_so
-							|| off.rm_eo != strlen(device_name))
-						break;
+				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
+				 || ((int)off[0].rm_eo != (int)strlen(device_name))
+				) {
+					goto next_line;
 				}
-				if (field == 1) {
-					/* uid:gid */
-
-					char *s, *s2;
-
-					/* Find : */
-					for (s=pos; s<end2 && *s!=':'; s++)
-						;
-					if (s == end2) break;
-
-					/* Parse UID */
-					uid = strtoul(pos, &s2, 10);
-					if (s != s2) {
-						struct passwd *pass;
-						char *_unam = xstrndup(pos, s-pos);
-						pass = getpwnam(_unam);
-						free(_unam);
-						if (!pass) break;
-						uid = pass->pw_uid;
+			}
+
+			/* This line matches: stop parsing the file
+			 * after parsing the rest of fields */
+
+			/* 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);
+			}
+
+			/* 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 == '>' || *next == '=') {
+#if ENABLE_FEATURE_MDEV_RENAME_REGEXP
+				char *s, *p;
+				unsigned i, n;
+
+				aliaslink = *next;
+				val = next;
+				next = next_field(val);
+				/* substitute %1..9 with off[1..9], if any */
+				n = 0;
+				s = val;
+				while (*s)
+					if (*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++;
-					/* parse GID */
-					gid = strtoul(s, &s2, 10);
-					if (end2 != s2) {
-						struct group *grp;
-						char *_grnam = xstrndup(s, end2-s);
-						grp = getgrnam(_grnam);
-						free(_grnam);
-						if (!grp) break;
-						gid = grp->gr_gid;
-					}
-				}
-				if (field == 2) {
-					/* mode */
-
-					mode = strtoul(pos, &pos, 8);
-					if (pos != end2) break;
 				}
-				if (ENABLE_FEATURE_MDEV_EXEC && field == 3) {
-					// Command to run
-					const char *s = "@$*";
-					const char *s2;
-					s2 = strchr(s, *pos++);
-					if (!s2) {
-						// Force error
-						field = 1;
-						break;
-					}
-					if ((s2-s+1) & (1<<delete))
-						command = xstrndup(pos, end-pos);
+#else
+				aliaslink = *next;
+				val = next;
+				next = next_field(val);
+				alias = xstrdup(val + 1);
+#endif
+			}
+#endif /* ENABLE_FEATURE_MDEV_RENAME */
+
+			/* The rest (opt): command to run */
+			if (!next)
+				break;
+			val = next;
+			if (ENABLE_FEATURE_MDEV_EXEC) {
+				const char *s = "@$*";
+				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);
 				}
-
-				pos = end2;
 			}
+			/* end of field parsing */
+			break; /* we found matching line, stop */
+ next_line:
+			free(line);
+		} /* end of "while line is read from /etc/mdev.conf" */
+
+		free(line); /* in case we used "break" to get here */
+		fclose(fp);
+	}
+ end_parse:
 
-			/* Did everything parse happily? */
-
-			if (field > 2) break;
-			if (field) bb_error_msg_and_die("bad line %d",line);
+	if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
 
-			/* Next line */
-			pos = ++end;
-		}
-		munmap(conf, len);
- end_parse:	/* nothing */ ;
-	}
+		if (ENABLE_FEATURE_MDEV_RENAME)
+			unlink(device_name);
 
-	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) chown(device_name, uid, gid);
+		if (ENABLE_FEATURE_MDEV_CONF) {
+			chown(device_name, uid, gid);
+
+			if (ENABLE_FEATURE_MDEV_RENAME && alias) {
+				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);
+					}
+				}
+
+				/* 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);
+			}
+		}
 	}
-	if (command) {
-		/* setenv will leak memory, so use putenv */
+
+	if (ENABLE_FEATURE_MDEV_EXEC && command) {
+		/* 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) unlink(device_name);
+
+	if (delete)
+		unlink(device_name);
 }
 
 /* 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") || 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)
 {
 	return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
 }
@@ -238,12 +344,6 @@ 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);
@@ -255,16 +355,15 @@ 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 */
@@ -275,9 +374,9 @@ 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) {
@@ -287,51 +386,78 @@ static void load_firmware(const char *const firmware, const char *const sysfs_pa
 	}
 }
 
-int mdev_main(int argc, char **argv);
+int mdev_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 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);
+
+	/* 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");
 
-	/* Scan */
-
-	if (argc == 2 && !strcmp(argv[1],"-s")) {
+	if (argc == 2 && !strcmp(argv[1], "-s")) {
+		/* Scan:
+		 * mdev -s
+		 */
 		struct stat st;
 
 		xstat("/", &st);
 		root_major = major(st.st_dev);
 		root_minor = minor(st.st_dev);
 
+		/* 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) */
 		recursive_action("/sys/block",
 			ACTION_RECURSE | ACTION_FOLLOWLINKS,
 			fileAction, dirAction, temp, 0);
-
 		recursive_action("/sys/class",
 			ACTION_RECURSE | ACTION_FOLLOWLINKS,
 			fileAction, dirAction, temp, 0);
-
-	/* Hotplug */
-
 	} 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);
+			}
 		}
 	}
 
-	if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);
+	if (ENABLE_FEATURE_CLEAN_UP)
+		RELEASE_CONFIG_BUFFER(temp);
+
 	return 0;
 }