lvm2/lib/config/config.c

/*
 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
 * Copyright (C) 2004-2011 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-file.h"
#include "memlock.h"

#include <sys/stat.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include <ctype.h>
#include <math.h>
#include <float.h>

static const char *_config_source_names[] = {
	[CONFIG_UNDEFINED] = "undefined",
	[CONFIG_FILE] = "file",
	[CONFIG_MERGED_FILES] = "merged files",
	[CONFIG_STRING] = "string",
	[CONFIG_PROFILE] = "profile",
	[CONFIG_FILE_SPECIAL] = "special purpose"
};

struct config_file {
	off_t st_size;
	char *filename;
	int exists;
	int keep_open;
	struct device *dev;
};

struct config_source {
	config_source_t type;
	time_t timestamp;
	union {
		struct config_file *file;
		struct config_file *profile;
	} source;
};

/*
 * Map each ID to respective definition of the configuration item.
 */
static struct cfg_def_item _cfg_def_items[CFG_COUNT + 1] = {
#define cfg_section(id, name, parent, flags, since_version, comment) {id, parent, name, CFG_TYPE_SECTION, {0}, flags, since_version, comment},
#define cfg(id, name, parent, flags, type, default_value, since_version, comment) {id, parent, name, type, {.v_##type = default_value}, flags, since_version, comment},
#define cfg_runtime(id, name, parent, flags, type, since_version, comment) {id, parent, name, type, {.fn_##type = get_default_##id}, flags | CFG_DEFAULT_RUN_TIME, since_version, comment},
#define cfg_array(id, name, parent, flags, types, default_value, since_version, comment) {id, parent, name, CFG_TYPE_ARRAY | types, {.v_CFG_TYPE_STRING = default_value}, flags, since_version, comment},
#define cfg_array_runtime(id, name, parent, flags, types, since_version, comment) {id, parent, name, CFG_TYPE_ARRAY | types, {.fn_CFG_TYPE_STRING = get_default_##id}, flags | CFG_DEFAULT_RUN_TIME, since_version, comment},
#include "config_settings.h"
#undef cfg_section
#undef cfg
#undef cfg_runtime
#undef cfg_array
#undef cfg_array_runtime
};

config_source_t config_get_source_type(struct dm_config_tree *cft)
{
	struct config_source *cs = dm_config_get_custom(cft);
	return cs ? cs->type : CONFIG_UNDEFINED;
}

/*
 * public interface
 */
struct dm_config_tree *config_open(config_source_t source,
				   const char *filename,
				   int keep_open)
{
	struct dm_config_tree *cft = dm_config_create();
	struct config_source *cs;
	struct config_file *cf;

	if (!cft)
		return NULL;

	if (!(cs = dm_pool_zalloc(cft->mem, sizeof(struct config_source)))) {
		log_error("Failed to allocate config source.");
		goto fail;
	}

	if ((source == CONFIG_FILE) ||
	    (source == CONFIG_FILE_SPECIAL) ||
	    (source == CONFIG_PROFILE)) {
		if (!(cf = dm_pool_zalloc(cft->mem, sizeof(struct config_file)))) {
			log_error("Failed to allocate config file.");
			goto fail;
		}

		cf->keep_open = keep_open;
		if (filename &&
		    !(cf->filename = dm_pool_strdup(cft->mem, filename))) {
			log_error("Failed to duplicate filename.");
			goto fail;
		}

		cs->source.file = cf;
	}

	cs->type = source;
	dm_config_set_custom(cft, cs);
	return cft;
fail:
	dm_config_destroy(cft);
	return NULL;
}

/*
 * Doesn't populate filename if the file is empty.
 */
int config_file_check(struct dm_config_tree *cft, const char **filename, struct stat *info)
{
	struct config_source *cs = dm_config_get_custom(cft);
	struct config_file *cf;
	struct stat _info;

	if ((cs->type != CONFIG_FILE) &&
	    (cs->type != CONFIG_PROFILE) &&
	    (cs->type != CONFIG_FILE_SPECIAL)) {
		log_error(INTERNAL_ERROR "config_file_check: expected file, special file or "
					 "profile config source, found %s config source.",
					 _config_source_names[cs->type]);
		return 0;
	}

	if (!info)
		info = &_info;

	cf = cs->source.file;

	if (stat(cf->filename, info)) {
		log_sys_error("stat", cf->filename);
		cf->exists = 0;
		return 0;
	}

	if (!S_ISREG(info->st_mode)) {
		log_error("%s is not a regular file", cf->filename);
		cf->exists = 0;
		return 0;
	}

	cs->timestamp = info->st_ctime;
	cf->exists = 1;
	cf->st_size = info->st_size;

	if (info->st_size == 0)
		log_verbose("%s is empty", cf->filename);
	else if (filename)
		*filename = cf->filename;

	return 1;
}

/*
 * Return 1 if config files ought to be reloaded
 */
int config_file_changed(struct dm_config_tree *cft)
{
	struct config_source *cs = dm_config_get_custom(cft);
	struct config_file *cf;
	struct stat info;

	if (cs->type != CONFIG_FILE) {
		log_error(INTERNAL_ERROR "config_file_changed: expected file config source, "
					 "found %s config source.", _config_source_names[cs->type]);
		return 0;
	}

	cf = cs->source.file;

	if (!cf->filename)
		return 0;

	if (stat(cf->filename, &info) == -1) {
		/* Ignore a deleted config file: still use original data */
		if (errno == ENOENT) {
			if (!cf->exists)
				return 0;
			log_very_verbose("Config file %s has disappeared!",
					 cf->filename);
			goto reload;
		}
		log_sys_error("stat", cf->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",
			  cf->filename);
		goto reload;
	}

	/* Unchanged? */
	if (cs->timestamp == info.st_ctime && cf->st_size == info.st_size)
		return 0;

      reload:
	log_verbose("Detected config file change to %s", cf->filename);
	return 1;
}

void config_destroy(struct dm_config_tree *cft)
{
	struct config_source *cs;
	struct config_file *cf;

	if (!cft)
		return;

	cs = dm_config_get_custom(cft);

	if ((cs->type == CONFIG_FILE) ||
	    (cs->type == CONFIG_PROFILE) ||
	    (cs->type == CONFIG_FILE_SPECIAL)) {
		cf = cs->source.file;
		if (cf && cf->dev)
			if (!dev_close(cf->dev))
				stack;
	}

	dm_config_destroy(cft);
}

struct dm_config_tree *config_file_open_and_read(const char *config_file,
						 config_source_t source)
{
	struct dm_config_tree *cft;
	struct stat info;

	if (!(cft = config_open(source, config_file, 0))) {
		log_error("config_tree allocation failed");
		return NULL;
	}

	/* Is there a config file? */
	if (stat(config_file, &info) == -1) {
		/* Profile file must be present! */
		if (errno == ENOENT && (source != CONFIG_PROFILE))
			return cft;
		log_sys_error("stat", config_file);
		goto bad;
	}

	log_very_verbose("Loading config file: %s", config_file);
	if (!config_file_read(cft)) {
		log_error("Failed to load config file %s", config_file);
		goto bad;
	}

	return cft;
bad:
	config_destroy(cft);
	return NULL;
}

/*
 * Returns config tree if it was removed.
 */
struct dm_config_tree *remove_config_tree_by_source(struct cmd_context *cmd,
						    config_source_t source)
{
	struct dm_config_tree *previous_cft = NULL;
	struct dm_config_tree *cft = cmd->cft;
	struct config_source *cs;

	while (cft) {
		cs = dm_config_get_custom(cft);
		if (cs && (cs->type == source)) {
			if (previous_cft) {
				previous_cft->cascade = cft->cascade;
				cmd->cft = previous_cft;
			} else
				cmd->cft = cft->cascade;
			cft->cascade = NULL;
			break;
		}
		previous_cft = cft;
		cft = cft->cascade;
	}

	return cft;
}

int override_config_tree_from_string(struct cmd_context *cmd,
				     const char *config_settings)
{
	struct dm_config_tree *cft_new;
	struct config_source *cs = dm_config_get_custom(cmd->cft);

	/*
	 * Follow this sequence:
	 * CONFIG_STRING -> CONFIG_PROFILE -> CONFIG_FILE/CONFIG_MERGED_FILES
	 */

	if (cs->type == CONFIG_STRING) {
		log_error(INTERNAL_ERROR "override_config_tree_from_string: "
			  "config cascade already contains a string config.");
		return 0;
	}

	if (!(cft_new = dm_config_from_string(config_settings))) {
		log_error("Failed to set overridden configuration entries.");
		return 0;
	}

	if (!(cs = dm_pool_zalloc(cft_new->mem, sizeof(struct config_source)))) {
		log_error("Failed to allocate config source.");
		dm_config_destroy(cft_new);
		return 0;
	}

	cs->type = CONFIG_STRING;
	dm_config_set_custom(cft_new, cs);

	cmd->cft = dm_config_insert_cascaded_tree(cft_new, cmd->cft);

	return 1;
}

int override_config_tree_from_profile(struct cmd_context *cmd,
				      struct profile *profile)
{
	struct dm_config_tree *cft = cmd->cft, *cft_string = NULL;
	struct config_source *cs = dm_config_get_custom(cft);

	/*
	 * Follow this sequence:
	 * CONFIG_STRING -> CONFIG_PROFILE -> CONFIG_FILE/CONFIG_MERGED_FILES
	 */

	if (!profile->cft && !load_profile(cmd, profile))
		return_0;

	if (cs->type == CONFIG_STRING) {
		cft_string = cft;
		cft = cft->cascade;
		cs = dm_config_get_custom(cft);
		if (cs->type == CONFIG_PROFILE) {
			log_error(INTERNAL_ERROR "override_config_tree_from_profile: "
				  "config cascade already contains a profile config.");
			return 0;
		}
		dm_config_insert_cascaded_tree(cft_string, profile->cft);
	}

	cmd->cft = dm_config_insert_cascaded_tree(profile->cft, cft);

	cmd->cft = cft_string ? : profile->cft;

	return 1;
}

int config_file_read_fd(struct dm_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)
{
	char *fb, *fe;
	int r = 0;
	int use_mmap = 1;
	off_t mmap_offset = 0;
	char *buf = NULL;
	struct config_source *cs = dm_config_get_custom(cft);

	if ((cs->type != CONFIG_FILE) &&
	    (cs->type != CONFIG_PROFILE) &&
	    (cs->type != CONFIG_FILE_SPECIAL)) {
		log_error(INTERNAL_ERROR "config_file_read_fd: expected file, special file "
					 "or profile config source, found %s config source.",
					 _config_source_names[cs->type]);
		return 0;
	}

	/* 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 */
		fb = mmap((caddr_t) 0, size + mmap_offset, PROT_READ,
			  MAP_PRIVATE, dev_fd(dev), offset - mmap_offset);
		if (fb == (caddr_t) (-1)) {
			log_sys_error("mmap", dev_name(dev));
			goto out;
		}
		fb = fb + mmap_offset;
	} else {
		if (!(buf = dm_malloc(size + size2))) {
			log_error("Failed to allocate circular buffer.");
			return 0;
		}
		if (!dev_read_circular(dev, (uint64_t) offset, size,
				       (uint64_t) offset2, size2, buf)) {
			goto out;
		}
		fb = buf;
	}

	if (checksum_fn && checksum !=
	    (checksum_fn(checksum_fn(INITIAL_CRC, (const uint8_t *)fb, size),
			 (const uint8_t *)(fb + size), size2))) {
		log_error("%s: Checksum error", dev_name(dev));
		goto out;
	}

	fe = fb + size + size2;
	if (!dm_config_parse(cft, fb, fe))
		goto_out;

	r = 1;

      out:
	if (!use_mmap)
		dm_free(buf);
	else {
		/* unmap the file */
		if (munmap(fb - mmap_offset, size + mmap_offset)) {
			log_sys_error("munmap", dev_name(dev));
			r = 0;
		}
	}

	return r;
}

int config_file_read(struct dm_config_tree *cft)
{
	const char *filename = NULL;
	struct config_source *cs = dm_config_get_custom(cft);
	struct config_file *cf;
	struct stat info;
	int r;

	if (!config_file_check(cft, &filename, &info))
		return_0;

	/* Nothing to do.  E.g. empty file. */
	if (!filename)
		return 1;

	cf = cs->source.file;

	if (!cf->dev) {
		if (!(cf->dev = dev_create_file(filename, NULL, NULL, 1)))
			return_0;

		if (!dev_open_readonly_buffered(cf->dev))
			return_0;
	}

	r = config_file_read_fd(cft, cf->dev, 0, (size_t) info.st_size, 0, 0,
				(checksum_fn_t) NULL, 0);

	if (!cf->keep_open) {
		if (!dev_close(cf->dev))
			stack;
		cf->dev = NULL;
	}

	return r;
}

time_t config_file_timestamp(struct dm_config_tree *cft)
{
	struct config_source *cs = dm_config_get_custom(cft);
	return cs->timestamp;
}

#define cfg_def_get_item_p(id) (&_cfg_def_items[id])
#define cfg_def_get_default_value_hint(cmd,item,type,profile) ((item->flags & CFG_DEFAULT_RUN_TIME) ? item->default_value.fn_##type(cmd,profile) : item->default_value.v_##type)
#define cfg_def_get_default_value(cmd,item,type,profile) (item->flags & CFG_DEFAULT_UNDEFINED ? 0 : cfg_def_get_default_value_hint(cmd,item,type,profile))

static int _cfg_def_make_path(char *buf, size_t buf_size, int id, cfg_def_item_t *item, int xlate)
{
	int variable = item->flags & CFG_NAME_VARIABLE;
	int parent_id = item->parent;
	int count, n;

	if (id == parent_id)
		return 0;

	count = _cfg_def_make_path(buf, buf_size, parent_id, cfg_def_get_item_p(parent_id), xlate);
	if ((n = dm_snprintf(buf + count, buf_size - count, "%s%s%s%s",
			     count ? "/" : "",
			     xlate && variable ? "<" : "",
			     !xlate && variable ? "#" : item->name,
			     xlate && variable ? ">" : "")) < 0) {
		log_error(INTERNAL_ERROR "_cfg_def_make_path: supplied buffer too small for %s/%s",
					  cfg_def_get_item_p(parent_id)->name, item->name);
		buf[0] = '\0';
		return 0;
	}

	return count + n;
}

int config_def_get_path(char *buf, size_t buf_size, int id)
{
	return _cfg_def_make_path(buf, buf_size, id, cfg_def_get_item_p(id), 0);
}

static void _get_type_name(char *buf, size_t buf_size, cfg_def_type_t type)
{
	(void) dm_snprintf(buf, buf_size, "%s%s%s%s%s%s",
			   (type & CFG_TYPE_ARRAY) ?
				((type & ~CFG_TYPE_ARRAY) ?
				 " array with values of type:" : " array") : "",
			   (type & CFG_TYPE_SECTION) ? " section" : "",
			   (type & CFG_TYPE_BOOL) ?  " boolean" : "",
			   (type & CFG_TYPE_INT) ? " integer" : "",
			   (type & CFG_TYPE_FLOAT) ?  " float" : "",
			   (type & CFG_TYPE_STRING) ? " string" : "");
}

static void _log_type_error(const char *path, cfg_def_type_t actual,
			    cfg_def_type_t expected, int suppress_messages)
{
	static char actual_type_name[128];
	static char expected_type_name[128];

	_get_type_name(actual_type_name, sizeof(actual_type_name), actual);
	_get_type_name(expected_type_name, sizeof(expected_type_name), expected);

	log_warn_suppress(suppress_messages, "Configuration setting \"%s\" has invalid type. "
					     "Found%s, expected%s.", path,
					     actual_type_name, expected_type_name);
}

static struct dm_config_value *_get_def_array_values(struct dm_config_tree *cft,
						     const cfg_def_item_t *def)
{
	char *enc_value, *token, *p, *r;
	struct dm_config_value *array = NULL, *v = NULL, *oldv = NULL;

	if (!def->default_value.v_CFG_TYPE_STRING) {
		if (!(array = dm_config_create_value(cft))) {
			log_error("Failed to create default empty array for %s.", def->name);
			return NULL;
		}
		array->type = DM_CFG_EMPTY_ARRAY;
		return array;
	}

	if (!(p = token = enc_value = dm_strdup(def->default_value.v_CFG_TYPE_STRING))) {
		log_error("_get_def_array_values: dm_strdup failed");
		return NULL;
	}
	/* Proper value always starts with '#'. */
	if (token[0] != '#')
		goto bad;

	while (token) {
		/* Move to type identifier. Error on no char. */
		token++;
		if (!token[0])
			goto bad;

		/* Move to the actual value and decode any "##" into "#". */
		p = token + 1;
		while ((p = strchr(p, '#')) && p[1] == '#') {
			memmove(p, p + 1, strlen(p));
			p++;
		}
		/* Separate the value out of the whole string. */
		if (p)
			p[0] = '\0';

		if (!(v = dm_config_create_value(cft))) {
			log_error("Failed to create default config array value for %s.", def->name);
			dm_free(enc_value);
			return NULL;
		}
		if (oldv)
			oldv->next = v;
		if (!array)
			array = v;

		switch (toupper(token[0])) {
			case 'I':
			case 'B':
				v->v.i = strtoll(token + 1, &r, 10);
				if (*r)
					goto bad;
				v->type = DM_CFG_INT;
				break;
			case 'F':
				v->v.f = strtod(token + 1, &r);
				if (*r)
					goto bad;
				v->type = DM_CFG_FLOAT;
				break;
			case 'S':
				if (!(r = dm_pool_strdup(cft->mem, token + 1))) {
					dm_free(enc_value);
					log_error("Failed to duplicate token for default "
						  "array value of %s.", def->name);
					return NULL;
				}
				v->v.str = r;
				v->type = DM_CFG_STRING;
				break;
			default:
				goto bad;
		}

		oldv = v;
		token = p;
	}

	dm_free(enc_value);
	return array;
bad:
	log_error(INTERNAL_ERROR "Default array value malformed for \"%s\", "
		  "value: \"%s\", token: \"%s\".", def->name,
		  def->default_value.v_CFG_TYPE_STRING, token);
	dm_free(enc_value);
	return NULL;
}

static int _config_def_check_node_single_value(struct cft_check_handle *handle,
					       const char *rp, const struct dm_config_value *v,
					       const cfg_def_item_t *def)