Imported Upstream version 2.02.79upstream/2.02.79

1 files changed, 1382 insertions, 0 deletions

diff --git a/lib/config/config.c b/lib/config/config.c
new file mode 100644
index 0000000..72908f2
--- /dev/null
+++ b/lib/config/config.c
@@ -0,0 +1,1382 @@
+/*
+ * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
+ * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "lib.h"
+#include "config.h"
+#include "crc.h"
+#include "device.h"
+#include "str_list.h"
+#include "toolcontext.h"
+#include "lvm-string.h"
+#include "lvm-file.h"
+
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <ctype.h>
+
+#define SECTION_B_CHAR '{'
+#define SECTION_E_CHAR '}'
+
+enum {
+	TOK_INT,
+	TOK_FLOAT,
+	TOK_STRING,		/* Single quotes */
+	TOK_STRING_ESCAPED,	/* Double quotes */
+	TOK_EQ,
+	TOK_SECTION_B,
+	TOK_SECTION_E,
+	TOK_ARRAY_B,
+	TOK_ARRAY_E,
+	TOK_IDENTIFIER,
+	TOK_COMMA,
+	TOK_EOF
+};
+
+struct parser {
+	const char *fb, *fe;		/* file limits */
+
+	int t;			/* token limits and type */
+	const char *tb, *te;
+
+	int fd;			/* descriptor for file being parsed */
+	int line;		/* line number we are on */
+
+	struct dm_pool *mem;
+};
+
+struct cs {
+	struct config_tree cft;
+	struct dm_pool *mem;
+	time_t timestamp;
+	char *filename;
+	int exists;
+	int keep_open;
+	struct device *dev;
+};
+
+struct output_line {
+	FILE *fp;
+	struct dm_pool *mem;
+	putline_fn putline;
+	void *putline_baton;
+};
+
+static void _get_token(struct parser *p, int tok_prev);
+static void _eat_space(struct parser *p);
+static struct config_node *_file(struct parser *p);
+static struct config_node *_section(struct parser *p);
+static struct config_value *_value(struct parser *p);
+static struct config_value *_type(struct parser *p);
+static int _match_aux(struct parser *p, int t);
+static struct config_value *_create_value(struct dm_pool *mem);
+static struct config_node *_create_node(struct dm_pool *mem);
+static char *_dup_tok(struct parser *p);
+
+static const int sep = '/';
+
+#define MAX_INDENT 32
+
+#define match(t) do {\
+   if (!_match_aux(p, (t))) {\
+	log_error("Parse error at byte %" PRIptrdiff_t " (line %d): unexpected token", \
+		  p->tb - p->fb + 1, p->line); \
+      return 0;\
+   } \
+} while(0);
+
+static int _tok_match(const char *str, const char *b, const char *e)
+{
+	while (*str && (b != e)) {
+		if (*str++ != *b++)
+			return 0;
+	}
+
+	return !(*str || (b != e));
+}
+
+/*
+ * public interface
+ */
+struct config_tree *create_config_tree(const char *filename, int keep_open)
+{
+	struct cs *c;
+	struct dm_pool *mem = dm_pool_create("config", 10 * 1024);
+
+	if (!mem) {
+		log_error("Failed to allocate config pool.");
+		return 0;
+	}
+
+	if (!(c = dm_pool_zalloc(mem, sizeof(*c)))) {
+		log_error("Failed to allocate config tree.");
+		dm_pool_destroy(mem);
+		return 0;
+	}
+
+	c->mem = mem;
+	c->cft.root = (struct config_node *) NULL;
+	c->timestamp = 0;
+	c->exists = 0;
+	c->keep_open = keep_open;
+	c->dev = 0;
+	if (filename)
+		c->filename = dm_pool_strdup(c->mem, filename);
+	return &c->cft;
+}
+
+void destroy_config_tree(struct config_tree *cft)
+{
+	struct cs *c = (struct cs *) cft;
+
+	if (c->dev)
+		dev_close(c->dev);
+
+	dm_pool_destroy(c->mem);
+}
+
+static int _parse_config_file(struct parser *p, struct config_tree *cft)
+{
+	p->tb = p->te = p->fb;
+	p->line = 1;
+	_get_token(p, TOK_SECTION_E);
+	if (!(cft->root = _file(p)))
+		return_0;
+
+	return 1;
+}
+
+struct config_tree *create_config_tree_from_string(struct cmd_context *cmd __attribute__((unused)),
+						   const char *config_settings)
+{
+	struct cs *c;
+	struct config_tree *cft;
+	struct parser *p;
+
+	if (!(cft = create_config_tree(NULL, 0)))
+		return_NULL;
+
+	c = (struct cs *) cft;
+	if (!(p = dm_pool_alloc(c->mem, sizeof(*p)))) {
+		log_error("Failed to allocate config tree parser.");
+		destroy_config_tree(cft);
+		return NULL;
+	}
+
+	p->mem = c->mem;
+	p->fb = config_settings;
+	p->fe = config_settings + strlen(config_settings);
+
+	if (!_parse_config_file(p, cft)) {
+		destroy_config_tree(cft);
+		return_NULL;
+	}
+
+	return cft;
+}
+
+int override_config_tree_from_string(struct cmd_context *cmd,
+				     const char *config_settings)
+{
+	if (!(cmd->cft_override = create_config_tree_from_string(cmd,config_settings))) {
+		log_error("Failed to set overridden configuration entries.");
+		return 1;
+	}
+
+	return 0;
+}
+
+int read_config_fd(struct config_tree *cft, struct device *dev,
+		   off_t offset, size_t size, off_t offset2, size_t size2,
+		   checksum_fn_t checksum_fn, uint32_t checksum)
+{
+	struct cs *c = (struct cs *) cft;
+	struct parser *p;
+	int r = 0;
+	int use_mmap = 1;
+	off_t mmap_offset = 0;
+	char *buf = NULL;
+
+	if (!(p = dm_pool_alloc(c->mem, sizeof(*p))))
+		return_0;
+	p->mem = c->mem;
+
+	/* Only use mmap with regular files */
+	if (!(dev->flags & DEV_REGULAR) || size2)
+		use_mmap = 0;
+
+	if (use_mmap) {
+		mmap_offset = offset % lvm_getpagesize();
+		/* memory map the file */
+		p->fb = mmap((caddr_t) 0, size + mmap_offset, PROT_READ,
+			     MAP_PRIVATE, dev_fd(dev), offset - mmap_offset);
+		if (p->fb == (caddr_t) (-1)) {
+			log_sys_error("mmap", dev_name(dev));
+			goto out;
+		}
+		p->fb = p->fb + mmap_offset;
+	} else {
+		if (!(buf = dm_malloc(size + size2)))
+			return_0;
+		if (!dev_read_circular(dev, (uint64_t) offset, size,
+				       (uint64_t) offset2, size2, buf)) {
+			goto out;
+		}
+		p->fb = buf;
+	}
+
+	if (checksum_fn && checksum !=
+	    (checksum_fn(checksum_fn(INITIAL_CRC, (const uint8_t *)p->fb, size),
+			 (const uint8_t *)(p->fb + size), size2))) {
+		log_error("%s: Checksum error", dev_name(dev));
+		goto out;
+	}
+
+	p->fe = p->fb + size + size2;
+
+	if (!_parse_config_file(p, cft))
+		goto_out;
+
+	r = 1;
+
+      out:
+	if (!use_mmap)
+		dm_free(buf);
+	else {
+		/* unmap the file */
+		if (munmap((char *) (p->fb - mmap_offset), size + mmap_offset)) {
+			log_sys_error("munmap", dev_name(dev));
+			r = 0;
+		}
+	}
+
+	return r;
+}
+
+int read_config_file(struct config_tree *cft)
+{
+	struct cs *c = (struct cs *) cft;
+	struct stat info;
+	int r = 1;
+
+	if (stat(c->filename, &info)) {
+		log_sys_error("stat", c->filename);
+		c->exists = 0;
+		return 0;
+	}
+
+	if (!S_ISREG(info.st_mode)) {
+		log_error("%s is not a regular file", c->filename);
+		c->exists = 0;
+		return 0;
+	}
+
+	c->exists = 1;
+
+	if (info.st_size == 0) {
+		log_verbose("%s is empty", c->filename);
+		return 1;
+	}
+
+	if (!c->dev) {
+		if (!(c->dev = dev_create_file(c->filename, NULL, NULL, 1)))
+			return_0;
+
+		if (!dev_open_flags(c->dev, O_RDONLY, 0, 0)) {
+			c->dev = 0;
+			return_0;
+		}
+	}
+
+	r = read_config_fd(cft, c->dev, 0, (size_t) info.st_size, 0, 0,
+			   (checksum_fn_t) NULL, 0);
+
+	if (!c->keep_open) {
+		dev_close(c->dev);
+		c->dev = 0;
+	}
+
+	c->timestamp = info.st_ctime;
+
+	return r;
+}
+
+time_t config_file_timestamp(struct config_tree *cft)
+{
+	struct cs *c = (struct cs *) cft;
+
+	return c->timestamp;
+}
+
+/*
+ * Return 1 if config files ought to be reloaded
+ */
+int config_file_changed(struct config_tree *cft)
+{
+	struct cs *c = (struct cs *) cft;
+	struct stat info;
+
+	if (!c->filename)
+		return 0;
+
+	if (stat(c->filename, &info) == -1) {
+		/* Ignore a deleted config file: still use original data */
+		if (errno == ENOENT) {
+			if (!c->exists)
+				return 0;
+			log_very_verbose("Config file %s has disappeared!",
+					 c->filename);
+			goto reload;
+		}
+		log_sys_error("stat", c->filename);
+		log_error("Failed to reload configuration files");
+		return 0;
+	}
+
+	if (!S_ISREG(info.st_mode)) {
+		log_error("Configuration file %s is not a regular file",
+			  c->filename);
+		goto reload;
+	}
+
+	/* Unchanged? */
+	if (c->timestamp == info.st_ctime)
+		return 0;
+
+      reload:
+	log_verbose("Detected config file change to %s", c->filename);
+	return 1;
+}
+
+static int _line_start(struct output_line *outline)
+{
+	if (!dm_pool_begin_object(outline->mem, 128)) {
+		log_error("dm_pool_begin_object failed for config line");
+		return 0;
+	}
+
+	return 1;
+}
+
+static int _line_append(struct output_line *outline, const char *fmt, ...)
+  __attribute__ ((format(printf, 2, 3)));
+static int _line_append(struct output_line *outline, const char *fmt, ...)
+{
+	char buf[4096];
+	va_list ap;
+	int n;
+
+	va_start(ap, fmt);
+	n = vsnprintf(&buf[0], sizeof buf - 1, fmt, ap);
+	va_end(ap);
+
+	if (n < 0 || n > (int) sizeof buf - 1) {
+		log_error("vsnprintf failed for config line");
+		return 0;
+	}
+
+	if (!dm_pool_grow_object(outline->mem, &buf[0], strlen(buf))) {
+		log_error("dm_pool_grow_object failed for config line");
+		return 0;
+	}
+
+	return 1;
+}
+
+#define line_append(args...) do {if (!_line_append(outline, args)) {return_0;}} while (0)
+
+static int _line_end(struct output_line *outline)
+{
+	const char *line;
+
+	if (!dm_pool_grow_object(outline->mem, "\0", 1)) {
+		log_error("dm_pool_grow_object failed for config line");
+		return 0;
+	}
+
+	line = dm_pool_end_object(outline->mem);
+	if (outline->putline)
+		outline->putline(line, outline->putline_baton);
+	else {
+		if (!outline->fp)
+			log_print("%s", line);
+		else
+			fprintf(outline->fp, "%s\n", line);
+	}
+
+	return 1;
+}
+
+static int _write_value(struct output_line *outline, const struct config_value *v)
+{
+	char *buf;
+
+	switch (v->type) {
+	case CFG_STRING:
+		if (!(buf = alloca(escaped_len(v->v.str)))) {
+			log_error("temporary stack allocation for a config "
+				  "string failed");
+			return 0;
+		}
+		line_append("\"%s\"", escape_double_quotes(buf, v->v.str));
+		break;
+
+	case CFG_FLOAT:
+		line_append("%f", v->v.r);
+		break;
+
+	case CFG_INT:
+		line_append("%" PRId64, v->v.i);
+		break;
+
+	case CFG_EMPTY_ARRAY:
+		line_append("[]");
+		break;
+
+	default:
+		log_error("_write_value: Unknown value type: %d", v->type);
+
+	}
+
+	return 1;
+}
+
+static int _write_config(const struct config_node *n, int only_one,
+			 struct output_line *outline, int level)
+{
+	char space[MAX_INDENT + 1];
+	int l = (level < MAX_INDENT) ? level : MAX_INDENT;
+	int i;
+
+	if (!n)
+		return 1;
+
+	for (i = 0; i < l; i++)
+		space[i] = '\t';
+	space[i] = '\0';
+
+	do {
+		if (!_line_start(outline))
+			return_0;
+		line_append("%s%s", space, n->key);
+		if (!n->v) {
+			/* it's a sub section */
+			line_append(" {");
+			if (!_line_end(outline))
+				return_0;
+			_write_config(n->child, 0, outline, level + 1);
+			if (!_line_start(outline))
+				return_0;
+			line_append("%s}", space);
+		} else {
+			/* it's a value */
+			const struct config_value *v = n->v;
+			line_append("=");
+			if (v->next) {
+				line_append("[");
+				while (v) {
+					if (!_write_value(outline, v))
+						return_0;
+					v = v->next;
+					if (v)
+						line_append(", ");
+				}
+				line_append("]");
+			} else
+				if (!_write_value(outline, v))
+					return_0;
+		}
+		if (!_line_end(outline))
+			return_0;
+		n = n->sib;
+	} while (n && !only_one);
+	/* FIXME: add error checking */
+	return 1;
+}
+
+int write_config_node(const struct config_node *cn, putline_fn putline, void *baton)
+{
+	struct output_line outline;
+	outline.fp = NULL;
+	if (!(outline.mem = dm_pool_create("config_line", 1024)))
+		return_0;
+	outline.putline = putline;
+	outline.putline_baton = baton;
+	if (!_write_config(cn, 0, &outline, 0)) {
+		dm_pool_destroy(outline.mem);
+		return_0;
+	}
+	dm_pool_destroy(outline.mem);
+	return 1;
+}
+
+int write_config_file(struct config_tree *cft, const char *file,
+		      int argc, char **argv)
+{
+	const struct config_node *cn;
+	int r = 1;
+	struct output_line outline;
+	outline.fp = NULL;
+	outline.putline = NULL;
+
+	if (!file)
+		file = "stdout";
+	else if (!(outline.fp = fopen(file, "w"))) {
+		log_sys_error("open", file);
+		return 0;
+	}
+
+	if (!(outline.mem = dm_pool_create("config_line", 1024))) {
+		r = 0;
+		goto_out;
+	}
+
+	log_verbose("Dumping configuration to %s", file);
+	if (!argc) {
+		if (!_write_config(cft->root, 0, &outline, 0)) {
+			log_error("Failure while writing to %s", file);
+			r = 0;
+		}
+	} else while (argc--) {
+		if ((cn = find_config_node(cft->root, *argv))) {
+			if (!_write_config(cn, 1, &outline, 0)) {
+				log_error("Failure while writing to %s", file);
+				r = 0;
+			}
+		} else {
+			log_error("Configuration node %s not found", *argv);
+			r = 0;
+		}
+		argv++;
+	}
+
+	dm_pool_destroy(outline.mem);
+
+out:
+	if (outline.fp && lvm_fclose(outline.fp, file)) {
+		stack;
+		r = 0;
+	}
+
+	return r;
+}
+
+/*
+ * parser
+ */
+static struct config_node *_file(struct parser *p)
+{
+	struct config_node *root = NULL, *n, *l = NULL;
+	while (p->t != TOK_EOF) {
+		if (!(n = _section(p)))
+			return_0;
+
+		if (!root)
+			root = n;
+		else
+			l->sib = n;
+		n->parent = root;
+		l = n;
+	}
+	return root;
+}
+
+static struct config_node *_section(struct parser *p)
+{
+	/* IDENTIFIER SECTION_B_CHAR VALUE* SECTION_E_CHAR */
+	struct config_node *root, *n, *l = NULL;
+	if (!(root = _create_node(p->mem)))
+		return_0;
+
+	if (!(root->key = _dup_tok(p)))
+		return_0;
+
+	match(TOK_IDENTIFIER);
+
+	if (p->t == TOK_SECTION_B) {
+		match(TOK_SECTION_B);
+		while (p->t != TOK_SECTION_E) {
+			if (!(n = _section(p)))
+				return_0;
+
+			if (!root->child)
+				root->child = n;
+			else
+				l->sib = n;
+			n->parent = root;
+			l = n;
+		}
+		match(TOK_SECTION_E);
+	} else {
+		match(TOK_EQ);
+		if (!(root->v = _value(p)))
+			return_0;
+	}
+
+	return root;
+}
+
+static struct config_value *_value(struct parser *p)
+{
+	/* '[' TYPE* ']' | TYPE */
+	struct config_value *h = NULL, *l, *ll = NULL;
+	if (p->t == TOK_ARRAY_B) {
+		match(TOK_ARRAY_B);
+		while (p->t != TOK_ARRAY_E) {
+			if (!(l = _type(p)))
+				return_0;
+
+			if (!h)
+				h = l;
+			else
+				ll->next = l;
+			ll = l;
+
+			if (p->t == TOK_COMMA)
+				match(TOK_COMMA);
+		}
+		match(TOK_ARRAY_E);
+		/*
+		 * Special case for an empty array.
+		 */
+		if (!h) {
+			if (!(h = _create_value(p->mem)))
+				return NULL;
+
+			h->type = CFG_EMPTY_ARRAY;
+		}
+
+	} else
+		h = _type(p);
+
+	return h;
+}
+
+static struct config_value *_type(struct parser *p)
+{
+	/* [+-]{0,1}[0-9]+ | [0-9]*\.[0-9]* | ".*" */
+	struct config_value *v = _create_value(p->mem);
+	char *str;
+
+	if (!v)
+		return NULL;
+
+	switch (p->t) {
+	case TOK_INT:
+		v->type = CFG_INT;
+		v->v.i = strtoll(p->tb, NULL, 0);	/* FIXME: check error */
+		match(TOK_INT);
+		break;
+
+	case TOK_FLOAT:
+		v->type = CFG_FLOAT;
+		v->v.r = strtod(p->tb, NULL);	/* FIXME: check error */
+		match(TOK_FLOAT);
+		break;
+
+	case TOK_STRING:
+		v->type = CFG_STRING;
+
+		p->tb++, p->te--;	/* strip "'s */
+		if (!(v->v.str = _dup_tok(p)))
+			return_0;
+		p->te++;
+		match(TOK_STRING);
+		break;
+
+	case TOK_STRING_ESCAPED:
+		v->type = CFG_STRING;
+
+		p->tb++, p->te--;	/* strip "'s */
+		if (!(str = _dup_tok(p)))
+			return_0;
+		unescape_double_quotes(str);
+		v->v.str = str;
+		p->te++;
+		match(TOK_STRING_ESCAPED);
+		break;
+
+	default:
+		log_error("Parse error at byte %" PRIptrdiff_t " (line %d): expected a value",
+			  p->tb - p->fb + 1, p->line);
+		return 0;
+	}
+	return v;
+}
+
+static int _match_aux(struct parser *p, int t)
+{
+	if (p->t != t)
+		return 0;
+
+	_get_token(p, t);
+	return 1;
+}
+
+/*
+ * tokeniser
+ */
+static void _get_token(struct parser *p, int tok_prev)
+{
+	int values_allowed = 0;
+
+	const char *te;
+
+	p->tb = p->te;
+	_eat_space(p);
+	if (p->tb == p->fe || !*p->tb) {
+		p->t = TOK_EOF;
+		return;
+	}
+
+	/* Should next token be interpreted as value instead of identifier? */
+	if (tok_prev == TOK_EQ || tok_prev == TOK_ARRAY_B ||
+	    tok_prev == TOK_COMMA)
+		values_allowed = 1;
+
+	p->t = TOK_INT;		/* fudge so the fall through for
+				   floats works */
+
+	te = p->te;
+	switch (*te) {
+	case SECTION_B_CHAR:
+		p->t = TOK_SECTION_B;
+		te++;
+		break;
+
+	case SECTION_E_CHAR:
+		p->t = TOK_SECTION_E;
+		te++;
+		break;
+
+	case '[':
+		p->t = TOK_ARRAY_B;
+		te++;
+		break;
+
+	case ']':
+		p->t = TOK_ARRAY_E;
+		te++;
+		break;
+
+	case ',':
+		p->t = TOK_COMMA;
+		te++;
+		break;
+
+	case '=':
+		p->t = TOK_EQ;
+		te++;
+		break;
+
+	case '"':
+		p->t = TOK_STRING_ESCAPED;
+		te++;
+		while ((te != p->fe) && (*te) && (*te != '"')) {
+			if ((*te == '\\') && (te + 1 != p->fe) &&
+			    *(te + 1))
+				te++;
+			te++;
+		}
+
+		if ((te != p->fe) && (*te))
+			te++;
+		break;
+
+	case '\'':
+		p->t = TOK_STRING;
+		te++;
+		while ((te != p->fe) && (*te) && (*te != '\''))
+			te++;
+
+		if ((te != p->fe) && (*te))
+			te++;
+		break;
+
+	case '.':
+		p->t = TOK_FLOAT;
+	case '0':
+	case '1':
+	case '2':
+	case '3':
+	case '4':
+	case '5':
+	case '6':
+	case '7':
+	case '8':
+	case '9':
+	case '+':
+	case '-':
+		if (values_allowed) {
+			te++;
+			while ((te != p->fe) && (*te)) {
+				if (*te == '.') {
+					if (p->t == TOK_FLOAT)
+						break;
+					p->t = TOK_FLOAT;
+				} else if (!isdigit((int) *te))
+					break;
+				te++;
+			}
+			break;
+		}
+
+	default:
+		p->t = TOK_IDENTIFIER;
+		while ((te != p->fe) && (*te) && !isspace(*te) &&
+		       (*te != '#') && (*te != '=') &&
+		       (*te != SECTION_B_CHAR) &&
+		       (*te != SECTION_E_CHAR))
+			te++;
+		break;
+	}
+
+	p->te = te;
+}
+
+static void _eat_space(struct parser *p)
+{
+	while ((p->tb != p->fe) && (*p->tb)) {
+		if (*p->te == '#')
+			while ((p->te != p->fe) && (*p->te) && (*p->te != '\n'))
+				p->te++;
+
+		else if (isspace(*p->te)) {
+			while ((p->te != p->fe) && (*p->te) && isspace(*p->te)) {
+				if (*p->te == '\n')
+					p->line++;
+				p->te++;
+			}
+		}
+
+		else
+			return;
+
+		p->tb = p->te;
+	}
+}
+
+/*
+ * memory management
+ */
+static struct config_value *_create_value(struct dm_pool *mem)
+{
+	return dm_pool_zalloc(mem, sizeof(struct config_value));
+}
+
+static struct config_node *_create_node(struct dm_pool *mem)
+{
+	return dm_pool_zalloc(mem, sizeof(struct config_node));
+}
+
+static char *_dup_tok(struct parser *p)
+{
+	size_t len = p->te - p->tb;
+	char *str = dm_pool_alloc(p->mem, len + 1);
+	if (!str)
+		return_0;
+	strncpy(str, p->tb, len);
+	str[len] = '\0';
+	return str;
+}
+
+/*
+ * utility functions
+ */
+static const struct config_node *_find_config_node(const struct config_node *cn,
+						   const char *path)
+{
+	const char *e;
+	const struct config_node *cn_found = NULL;
+
+	while (cn) {
+		/* trim any leading slashes */
+		while (*path && (*path == sep))
+			path++;
+
+		/* find the end of this segment */
+		for (e = path; *e && (*e != sep); e++) ;
+
+		/* hunt for the node */
+		cn_found = NULL;
+		while (cn) {
+			if (_tok_match(cn->key, path, e)) {
+				/* Inefficient */
+				if (!cn_found)
+					cn_found = cn;
+				else
+					log_warn("WARNING: Ignoring duplicate"
+						 " config node: %s ("
+						 "seeking %s)", cn->key, path);
+			}
+
+			cn = cn->sib;
+		}
+
+		if (cn_found && *e)
+			cn = cn_found->child;
+		else
+			break;	/* don't move into the last node */
+
+		path = e;
+	}
+
+	return cn_found;
+}
+
+static const struct config_node *_find_first_config_node(const struct config_node *cn1,
+							 const struct config_node *cn2,
+							 const char *path)
+{
+	const struct config_node *cn;
+
+	if (cn1 && (cn = _find_config_node(cn1, path)))
+		return cn;
+
+	if (cn2 && (cn = _find_config_node(cn2, path)))
+		return cn;
+
+	return NULL;
+}
+
+const struct config_node *find_config_node(const struct config_node *cn,
+					   const char *path)
+{
+	return _find_config_node(cn, path);
+}
+
+static const char *_find_config_str(const struct config_node *cn1,
+				    const struct config_node *cn2,
+				    const char *path, const char *fail)
+{
+	const struct config_node *n = _find_first_config_node(cn1, cn2, path);
+
+	/* Empty strings are ignored */
+	if ((n && n->v && n->v->type == CFG_STRING) && (*n->v->v.str)) {
+		log_very_verbose("Setting %s to %s", path, n->v->v.str);
+		return n->v->v.str;
+	}
+
+	if (fail)
+		log_very_verbose("%s not found in config: defaulting to %s",
+				 path, fail);
+	return fail;
+}
+
+const char *find_config_str(const struct config_node *cn,
+			    const char *path, const char *fail)
+{
+	return _find_config_str(cn, NULL, path, fail);
+}
+
+static int64_t _find_config_int64(const struct config_node *cn1,
+				  const struct config_node *cn2,
+				  const char *path, int64_t fail)
+{
+	const struct config_node *n = _find_first_config_node(cn1, cn2, path);
+
+	if (n && n->v && n->v->type == CFG_INT) {
+		log_very_verbose("Setting %s to %" PRId64, path, n->v->v.i);
+		return n->v->v.i;
+	}
+
+	log_very_verbose("%s not found in config: defaulting to %" PRId64,
+			 path, fail);
+	return fail;
+}
+
+int find_config_int(const struct config_node *cn, const char *path, int fail)
+{
+	/* FIXME Add log_error message on overflow */
+	return (int) _find_config_int64(cn, NULL, path, (int64_t) fail);
+}
+
+static float _find_config_float(const struct config_node *cn1,
+				const struct config_node *cn2,
+				const char *path, float fail)
+{
+	const struct config_node *n = _find_first_config_node(cn1, cn2, path);
+
+	if (n && n->v && n->v->type == CFG_FLOAT) {
+		log_very_verbose("Setting %s to %f", path, n->v->v.r);
+		return n->v->v.r;
+	}
+
+	log_very_verbose("%s not found in config: defaulting to %f",
+			 path, fail);
+
+	return fail;
+
+}
+
+float find_config_float(const struct config_node *cn, const char *path,
+			float fail)
+{
+	return _find_config_float(cn, NULL, path, fail);
+}
+
+const struct config_node *find_config_tree_node(struct cmd_context *cmd,
+					  const char *path)
+{
+	return _find_first_config_node(cmd->cft_override ? cmd->cft_override->root : NULL, cmd->cft->root, path);
+}
+
+const char *find_config_tree_str(struct cmd_context *cmd,
+				 const char *path, const char *fail)
+{
+	return _find_config_str(cmd->cft_override ? cmd->cft_override->root : NULL, cmd->cft->root, path, fail);
+}
+
+int find_config_tree_int(struct cmd_context *cmd, const char *path,
+			 int fail)
+{
+	/* FIXME Add log_error message on overflow */
+	return (int) _find_config_int64(cmd->cft_override ? cmd->cft_override->root : NULL, cmd->cft->root, path, (int64_t) fail);
+}
+
+float find_config_tree_float(struct cmd_context *cmd, const char *path,
+			     float fail)
+{
+	return _find_config_float(cmd->cft_override ? cmd->cft_override->root : NULL, cmd->cft->root, path, fail);
+}
+
+static int _str_in_array(const char *str, const char * const values[])
+{
+	int i;
+
+	for (i = 0; values[i]; i++)
+		if (!strcasecmp(str, values[i]))
+			return 1;
+
+	return 0;
+}
+
+static int _str_to_bool(const char *str, int fail)
+{
+	const char * const _true_values[]  = { "y", "yes", "on", "true", NULL };
+	const char * const _false_values[] = { "n", "no", "off", "false", NULL };
+
+	if (_str_in_array(str, _true_values))
+		return 1;
+
+	if (_str_in_array(str, _false_values))
+		return 0;
+
+	return fail;
+}
+
+static int _find_config_bool(const struct config_node *cn1,
+			     const struct config_node *cn2,
+			     const char *path, int fail)
+{
+	const struct config_node *n = _find_first_config_node(cn1, cn2, path);
+	const struct config_value *v;
+
+	if (!n)
+		return fail;
+
+	v = n->v;
+
+	switch (v->type) {
+	case CFG_INT:
+		return v->v.i ? 1 : 0;
+
+	case CFG_STRING:
+		return _str_to_bool(v->v.str, fail);
+	}
+
+	return fail;
+}
+
+int find_config_bool(const struct config_node *cn, const char *path, int fail)
+{
+	return _find_config_bool(cn, NULL, path, fail);
+}
+
+int find_config_tree_bool(struct cmd_context *cmd, const char *path, int fail)
+{
+	return _find_config_bool(cmd->cft_override ? cmd->cft_override->root : NULL, cmd->cft->root, path, fail);
+}
+
+int get_config_uint32(const struct config_node *cn, const char *path,
+		      uint32_t *result)
+{
+	const struct config_node *n;
+
+	n = find_config_node(cn, path);
+
+	if (!n || !n->v || n->v->type != CFG_INT)
+		return 0;
+
+	*result = n->v->v.i;
+	return 1;
+}
+
+int get_config_uint64(const struct config_node *cn, const char *path,
+		      uint64_t *result)
+{
+	const struct config_node *n;
+
+	n = find_config_node(cn, path);
+
+	if (!n || !n->v || n->v->type != CFG_INT)
+		return 0;
+
+	*result = (uint64_t) n->v->v.i;
+	return 1;
+}
+
+int get_config_str(const struct config_node *cn, const char *path,
+		   const char **result)
+{
+	const struct config_node *n;
+
+	n = find_config_node(cn, path);
+
+	if (!n || !n->v || n->v->type != CFG_STRING)
+		return 0;
+
+	*result = n->v->v.str;
+	return 1;
+}
+
+/* Insert cn2 after cn1 */
+static void _insert_config_node(struct config_node **cn1,
+				struct config_node *cn2)
+{
+	if (!*cn1) {
+		*cn1 = cn2;
+		cn2->sib = NULL;
+	} else {
+		cn2->sib = (*cn1)->sib;
+		(*cn1)->sib = cn2;
+	}
+}
+
+/*
+ * Merge section cn2 into section cn1 (which has the same name)
+ * overwriting any existing cn1 nodes with matching names.
+ */
+static void _merge_section(struct config_node *cn1, struct config_node *cn2)
+{
+	struct config_node *cn, *nextn, *oldn;
+	struct config_value *cv;
+
+	for (cn = cn2->child; cn; cn = nextn) {
+		nextn = cn->sib;
+
+		/* Skip "tags" */
+		if (!strcmp(cn->key, "tags"))
+			continue;
+
+		/* Subsection? */
+		if (!cn->v)
+			/* Ignore - we don't have any of these yet */
+			continue;
+		/* Not already present? */
+		if (!(oldn = (struct config_node*)find_config_node(cn1->child, cn->key))) {
+			_insert_config_node(&cn1->child, cn);
+			continue;
+		}
+		/* Merge certain value lists */
+		if ((!strcmp(cn1->key, "activation") &&
+		     !strcmp(cn->key, "volume_list")) ||
+		    (!strcmp(cn1->key, "devices") &&
+		     (!strcmp(cn->key, "filter") || !strcmp(cn->key, "types")))) {
+			cv = cn->v;
+			while (cv->next)
+				cv = cv->next;
+			cv->next = oldn->v;
+		}
+
+		/* Replace values */
+		oldn->v = cn->v;
+	}
+}
+
+static int _match_host_tags(struct dm_list *tags, const struct config_node *tn)
+{
+	const struct config_value *tv;
+	const char *str;
+
+	for (tv = tn->v; tv; tv = tv->next) {
+		if (tv->type != CFG_STRING)
+			continue;
+		str = tv->v.str;
+		if (*str == '@')
+			str++;
+		if (!*str)
+			continue;
+		if (str_list_match_item(tags, str))
+			return 1;
+	}
+
+	return 0;
+}
+
+/* Destructively merge a new config tree into an existing one */
+int merge_config_tree(struct cmd_context *cmd, struct config_tree *cft,
+		      struct config_tree *newdata)
+{
+	const struct config_node *root = cft->root;
+	struct config_node *cn, *nextn, *oldn, *cn2;
+	const struct config_node *tn;
+
+	for (cn = newdata->root; cn; cn = nextn) {
+		nextn = cn->sib;
+		/* Ignore tags section */
+		if (!strcmp(cn->key, "tags"))
+			continue;
+		/* If there's a tags node, skip if host tags don't match */
+		if ((tn = find_config_node(cn->child, "tags"))) {
+			if (!_match_host_tags(&cmd->tags, tn))
+				continue;
+		}
+		if (!(oldn = (struct config_node *)find_config_node(root, cn->key))) {
+			_insert_config_node(&cft->root, cn);
+			/* Remove any "tags" nodes */
+			for (cn2 = cn->child; cn2; cn2 = cn2->sib) {
+				if (!strcmp(cn2->key, "tags")) {
+					cn->child = cn2->sib;
+					continue;
+				}
+				if (cn2->sib && !strcmp(cn2->sib->key, "tags")) {
+					cn2->sib = cn2->sib->sib;
+					continue;
+				}
+			}
+			continue;
+		}
+		_merge_section(oldn, cn);
+	}
+
+	return 1;
+}
+
+/*
+ * Convert a token type to the char it represents.
+ */
+static char _token_type_to_char(int type)
+{
+	switch (type) {
+		case TOK_SECTION_B:
+			return SECTION_B_CHAR;
+		case TOK_SECTION_E:
+			return SECTION_E_CHAR;
+		default:
+			return 0;
+	}
+}
+
+/*
+ * Returns:
+ *  # of 'type' tokens in 'str'.
+ */
+static unsigned _count_tokens(const char *str, unsigned len, int type)
+{
+	char c;
+
+	c = _token_type_to_char(type);
+
+	return count_chars(str, len, c);
+}
+
+const char *config_parent_name(const struct config_node *n)
+{
+	return (n->parent ? n->parent->key : "(root)");
+}
+/*
+ * Heuristic function to make a quick guess as to whether a text
+ * region probably contains a valid config "section".  (Useful for
+ * scanning areas of the disk for old metadata.)
+ * Config sections contain various tokens, may contain other sections
+ * and strings, and are delimited by begin (type 'TOK_SECTION_B') and
+ * end (type 'TOK_SECTION_E') tokens.  As a quick heuristic, we just
+ * count the number of begin and end tokens, and see if they are
+ * non-zero and the counts match.
+ * Full validation of the section should be done with another function
+ * (for example, read_config_fd).
+ *
+ * Returns:
+ *  0 - probably is not a valid config section
+ *  1 - probably _is_ a valid config section
+ */
+unsigned maybe_config_section(const char *str, unsigned len)
+{
+	int begin_count;
+	int end_count;
+
+	begin_count = _count_tokens(str, len, TOK_SECTION_B);
+	end_count = _count_tokens(str, len, TOK_SECTION_E);
+
+	if (begin_count && end_count && (begin_count == end_count))
+		return 1;
+	else
+		return 0;
+}
+
+static struct config_value *_clone_config_value(struct dm_pool *mem, const struct config_value *v)
+{
+	struct config_value *new_cv;
+
+	if (!v)
+		return NULL;
+
+	if (!(new_cv = _create_value(mem))) {
+		log_error("Failed to clone config value.");
+		return NULL;
+	}
+
+	new_cv->type = v->type;
+	if (v->type == CFG_STRING) {
+		if (!(new_cv->v.str = dm_pool_strdup(mem, v->v.str))) {
+			log_error("Failed to clone config string value.");
+			return NULL;
+		}
+	} else
+		new_cv->v = v->v;
+
+	if (v->next && !(new_cv->next = _clone_config_value(mem, v->next)))
+		return_NULL;
+
+	return new_cv;
+}
+
+struct config_node *clone_config_node(struct dm_pool *mem, const struct config_node *cn,
+				      int siblings)
+{
+	struct config_node *new_cn;
+
+	if (!cn)
+		return NULL;
+
+	if (!(new_cn = _create_node(mem))) {
+		log_error("Failed to clone config node.");
+		return NULL;
+	}
+
+	if ((cn->key && !(new_cn->key = dm_pool_strdup(mem, cn->key)))) {
+		log_error("Failed to clone config node key.");
+		return NULL;
+	}
+
+	if ((cn->v && !(new_cn->v = _clone_config_value(mem, cn->v))) ||
+	    (cn->child && !(new_cn->child = clone_config_node(mem, cn->child, 1))) ||
+	    (siblings && cn->sib && !(new_cn->sib = clone_config_node(mem, cn->sib, siblings))))
+		return_NULL; /* 'new_cn' released with mem pool */
+
+	return new_cn;
+}