pvfs_resolve.c

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/* 
   Unix SMB/CIFS implementation.

   POSIX NTVFS backend - filename resolution

   Copyright (C) Andrew Tridgell 2004

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
  this is the core code for converting a filename from the format as
  given by a client to a posix filename, including any case-matching
  required, and checks for legal characters
*/


#include "includes.h"
#include "vfs_posix.h"
#include "system/dir.h"
#include "param/param.h"

/**
  compare two filename components. This is where the name mangling hook will go
*/
static int component_compare(struct pvfs_state *pvfs, const char *comp, const char *name)
{
	int ret;

	ret = strcasecmp_m(comp, name);

	if (ret != 0) {
		char *shortname = pvfs_short_name_component(pvfs, name);
		if (shortname) {
			ret = strcasecmp_m(comp, shortname);
			talloc_free(shortname);
		}
	}

	return ret;
}

/*
  search for a filename in a case insensitive fashion

  TODO: add a cache for previously resolved case-insensitive names
  TODO: add mangled name support
*/
static NTSTATUS pvfs_case_search(struct pvfs_state *pvfs, struct pvfs_filename *name)
{
	/* break into a series of components */
	int num_components;
	char **components;
	char *p, *partial_name;
	int i;

	/* break up the full name info pathname components */
	num_components=2;
	p = name->full_name + strlen(pvfs->base_directory) + 1;

	for (;*p;p++) {
		if (*p == '/') {
			num_components++;
		}
	}

	components = talloc_array(name, char *, num_components);
	p = name->full_name + strlen(pvfs->base_directory);
	*p++ = 0;

	components[0] = name->full_name;

	for (i=1;i<num_components;i++) {
		components[i] = p;
		p = strchr(p, '/');
		if (p) *p++ = 0;
		if (pvfs_is_reserved_name(pvfs, components[i])) {
			return NT_STATUS_ACCESS_DENIED;
		}
	}

	partial_name = talloc_strdup(name, components[0]);
	if (!partial_name) {
		return NT_STATUS_NO_MEMORY;
	}

	/* for each component, check if it exists as-is, and if not then
	   do a directory scan */
	for (i=1;i<num_components;i++) {
		char *test_name;
		DIR *dir;
		struct dirent *de;
		char *long_component;

		/* possibly remap from the short name cache */
		long_component = pvfs_mangled_lookup(pvfs, name, components[i]);
		if (long_component) {
			components[i] = long_component;
		}

		test_name = talloc_asprintf(name, "%s/%s", partial_name, components[i]);
		if (!test_name) {
			return NT_STATUS_NO_MEMORY;
		}

		/* check if this component exists as-is */
		if (stat(test_name, &name->st) == 0) {
			if (i<num_components-1 && !S_ISDIR(name->st.st_mode)) {
				return NT_STATUS_OBJECT_PATH_NOT_FOUND;
			}
			talloc_free(partial_name);
			partial_name = test_name;
			if (i == num_components - 1) {
				name->exists = true;
			}
			continue;
		}

		/* the filesystem might be case insensitive, in which
		   case a search is pointless unless the name is
		   mangled */
		if ((pvfs->flags & PVFS_FLAG_CI_FILESYSTEM) &&
		    !pvfs_is_mangled_component(pvfs, components[i])) {
			if (i < num_components-1) {
				return NT_STATUS_OBJECT_PATH_NOT_FOUND;
			}
			partial_name = test_name;
			continue;
		}
		
		dir = opendir(partial_name);
		if (!dir) {
			return pvfs_map_errno(pvfs, errno);
		}

		while ((de = readdir(dir))) {
			if (component_compare(pvfs, components[i], de->d_name) == 0) {
				break;
			}
		}

		if (!de) {
			if (i < num_components-1) {
				closedir(dir);
				return NT_STATUS_OBJECT_PATH_NOT_FOUND;
			}
		} else {
			components[i] = talloc_strdup(name, de->d_name);
		}
		test_name = talloc_asprintf(name, "%s/%s", partial_name, components[i]);
		talloc_free(partial_name);
		partial_name = test_name;

		closedir(dir);
	}

	if (!name->exists) {
		if (stat(partial_name, &name->st) == 0) {
			name->exists = true;
		}
	}

	talloc_free(name->full_name);
	name->full_name = partial_name;

	if (name->exists) {
		return pvfs_fill_dos_info(pvfs, name, -1);
	}

	return NT_STATUS_OK;
}

/*
  parse a alternate data stream name
*/
static NTSTATUS parse_stream_name(struct pvfs_filename *name, const char *s)
{
	char *p;
	name->stream_name = talloc_strdup(name, s+1);
	if (name->stream_name == NULL) {
		return NT_STATUS_NO_MEMORY;
	}
	p = strchr_m(name->stream_name, ':');
	if (p == NULL) {
		name->stream_id = pvfs_name_hash(name->stream_name, 
						 strlen(name->stream_name));
		return NT_STATUS_OK;
	}
	if (strcasecmp_m(p, ":$DATA") != 0) {
		return NT_STATUS_OBJECT_NAME_INVALID;
	}
	*p = 0;
	if (strcmp(name->stream_name, "") == 0) {
		/*
		 * we don't set stream_name to NULL, here
		 * as this would be wrong for directories
		 *
		 * pvfs_fill_dos_info() will set it to NULL
		 * if it's not a directory.
		 */
		name->stream_id = 0;
	} else {
		name->stream_id = pvfs_name_hash(name->stream_name, 
						 strlen(name->stream_name));
	}
						 
	return NT_STATUS_OK;	
}


/*
  convert a CIFS pathname to a unix pathname. Note that this does NOT
  take into account case insensitivity, and in fact does not access
  the filesystem at all. It is merely a reformatting and charset
  checking routine.

  errors are returned if the filename is illegal given the flags
*/
static NTSTATUS pvfs_unix_path(struct pvfs_state *pvfs, const char *cifs_name,
			       uint_t flags, struct pvfs_filename *name)
{
	char *ret, *p, *p_start;
	NTSTATUS status;

	name->original_name = talloc_strdup(name, cifs_name);
	name->stream_name = NULL;
	name->stream_id = 0;
	name->has_wildcard = false;

	while (*cifs_name == '\\') {
		cifs_name++;
	}

	if (*cifs_name == 0) {
		name->full_name = talloc_asprintf(name, "%s/.", pvfs->base_directory);
		if (name->full_name == NULL) {
			return NT_STATUS_NO_MEMORY;
		}
		return NT_STATUS_OK;
	}

	ret = talloc_asprintf(name, "%s/%s", pvfs->base_directory, cifs_name);
	if (ret == NULL) {
		return NT_STATUS_NO_MEMORY;
	}

	p = ret + strlen(pvfs->base_directory) + 1;

	/* now do an in-place conversion of '\' to '/', checking
	   for legal characters */
	p_start = p;

	while (*p) {
		size_t c_size;
		codepoint_t c = next_codepoint(lp_iconv_convenience(pvfs->ntvfs->ctx->lp_ctx), p, &c_size);
		switch (c) {
		case '\\':
			if (name->has_wildcard) {
				/* wildcards are only allowed in the last part
				   of a name */
				return NT_STATUS_ILLEGAL_CHARACTER;
			}
			if (p > p_start && (p[1] == '\\' || p[1] == '\0')) {
				/* see if it is definately a "\\" or
				 * a trailing "\". If it is then fail here,
				 * and let the next layer up try again after
				 * pvfs_reduce_name() if it wants to. This is
				 * much more efficient on average than always
				 * scanning for these separately
				 */
				return NT_STATUS_OBJECT_PATH_SYNTAX_BAD;
			} else {
				*p = '/';
			}
			break;
		case ':':
			if (!(flags & PVFS_RESOLVE_STREAMS)) {
				return NT_STATUS_ILLEGAL_CHARACTER;
			}
			if (name->has_wildcard) {
				return NT_STATUS_ILLEGAL_CHARACTER;
			}
			status = parse_stream_name(name, p);
			if (!NT_STATUS_IS_OK(status)) {
				return status;
			}
			*p-- = 0;
			break;
		case '*':
		case '>':
		case '<':
		case '?':
		case '"':
			if (!(flags & PVFS_RESOLVE_WILDCARD)) {
				return NT_STATUS_OBJECT_NAME_INVALID;
			}
			name->has_wildcard = true;
			break;
		case '/':
		case '|':
			return NT_STATUS_ILLEGAL_CHARACTER;
		case '.':
			/* see if it is definately a .. or
			   . component. If it is then fail here, and
			   let the next layer up try again after
			   pvfs_reduce_name() if it wants to. This is
			   much more efficient on average than always
			   scanning for these separately */
			if (p[1] == '.' && 
			    (p[2] == 0 || p[2] == '\\') &&
			    (p == p_start || p[-1] == '/')) {
				return NT_STATUS_OBJECT_PATH_SYNTAX_BAD;
			}
			if ((p[1] == 0 || p[1] == '\\') &&
			    (p == p_start || p[-1] == '/')) {
				return NT_STATUS_OBJECT_PATH_SYNTAX_BAD;
			}
			break;
		}

		p += c_size;
	}

	name->full_name = ret;

	return NT_STATUS_OK;
}


/*
  reduce a name that contains .. components or repeated \ separators
  return NULL if it can't be reduced
*/
static NTSTATUS pvfs_reduce_name(TALLOC_CTX *mem_ctx, 
				 struct smb_iconv_convenience *iconv_convenience, 
				 const char **fname, uint_t flags)
{
	codepoint_t c;
	size_t c_size, len;
	int i, num_components, err_count;
	char **components;
	char *p, *s, *ret;

	s = talloc_strdup(mem_ctx, *fname);
	if (s == NULL) return NT_STATUS_NO_MEMORY;

	for (num_components=1, p=s; *p; p += c_size) {
		c = next_codepoint(iconv_convenience, p, &c_size);
		if (c == '\\') num_components++;
	}

	components = talloc_array(s, char *, num_components+1);
	if (components == NULL) {
		talloc_free(s);
		return NT_STATUS_NO_MEMORY;
	}

	components[0] = s;
	for (i=0, p=s; *p; p += c_size) {
		c = next_codepoint(iconv_convenience, p, &c_size);
		if (c == '\\') {
			*p = 0;
			components[++i] = p+1;
		}
	}
	components[i+1] = NULL;

	/*
	  rather bizarre!