simple_restore.c

网络数据管理协议的开发

		if (n1[0] == '.' && n1[1] == '/')
			n1 += 2;
		else if (n1[0] == '/' ||
				 (n1[0] == '.' && n1[1] == '\0'))
			n1++;

		if (n2[0] == '.' && n2[1] == '/')
			n2 += 2;
		else if (n2[0] == '/' ||
				 (n2[0] == '.' && n2[1] == '\0'))
			n2++;
		
		if (strcmp(n1, n2) != 0)
		{
			(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
							   "Restore: ERROR: expected file: %s; read: %s.\n",
								  nameEnt->original_path, name);
			return(EIO);
		}
		
		err = restoreFile(info, name, &fileStat);
		if (err < 0)
		{
			return(EIO);
		}

		/*
		 * Notify the NDMP client that a file recovery succeeded or
		 * failed.
		 */
		(*modParams->fileRecoveredFunc)(modParams->daemonCookie,
										name,
										(err == 0 ? EPERM : 0));

		/*
		 * Check if the restore has been aborted
		 * or the NDMP connection broken.
		 */
		(*modParams->dispatchFunc)(modParams->daemonCookie, FALSE);
		if (info->params->abortFlag == TRUE)
		{
			return(EINTR);
		}
	}

	return(0);
}


/*
 * checkFile
 *   Determine if the specified file name should be restored by
 *   comparing the name to each name in the restore list.
 *   Look for exact match as well as if the name is a parent directory
 *   to a file in the restore list or is contained in a directory
 *   specified in the restore list.
 *
 *   Before comparing names, names are normalized by removing any
 *   leading / or ./. A name of .\0 is normalized to \0.
 *   A resulting normalized name of \0 implies the backup root
 *   directory of the dump.
 *
 * Parameters:
 *   info (input) - restore info.
 *   name (input) - file name to check.
 *
 * Returns:
 *  -2 - no match.
 *  -1 - name is a parent directory of a file in the list or
 *       name is contained in a directory from the list.
 *   otherwise - index into list of the exact matching name.
 */
static int
checkFile(RestoreInfo*	info,
		  char*			name)
{
	char*				ckname;
	u_long				cknamelen;
	u_long				namelen;
	u_long				i;
	int					match = -2;
	NdmpdModuleParams*	modParams = info->params->modParams;
	
	/*
	 * Remove leading ./
	 * Force . (backup root directory) to match everything.
	 */
	if (name[0] == '.' && name[1] == '/')
		name += 2;
	else if (name[0] == '.' && name[1] == '\0')
		name++;

	/*
	 * Always restore the backup root directory. 
	 * Still need to check for an exact match.
	 */
	if (name[0] == '\0')
		match = -1;
	
	/*
	 * Check against each name in the restore list until a
	 * match is found or until the end of the list is encountered.
	 */
	for (i = 0; ; i++)
	{
		ndmp_name*	nameEnt;
		nameEnt = (*modParams->getNameFunc)(modParams->daemonCookie,
											i);
		if (nameEnt == 0)
			break;
		
		ckname    = nameEnt->original_path;

		/* Remove leading ./ or / */
		if (ckname[0] == '.' && ckname[1] == '/')
			ckname += 2;
		else if (ckname[0] == '/' ||
				 (ckname[0] == '.' && ckname[1] == '\0'))
			ckname++;
		
		/* Root directory matches all names. */
		if (ckname[0] == '\0')
			match = -1;
		
		cknamelen = strlen(ckname);
		namelen   = strlen(name);
		
		if (namelen == cknamelen)
		{
			if (strcmp(name, ckname) == 0)
				return(i);
			continue;
		}
		
		if (namelen < cknamelen)
		{
			/*
			 * Its only a match if name is a parent directory of ckname.
			 */
			if (ckname[namelen] != '/')
				continue;
			
			if (strncmp(name, ckname, namelen) != 0)
				continue;

			/* Found a match but keep looking for an exact match. */
			match = -1;
			continue;
		}
		
		/*
		 * Its only a match now if ckname is a parent directory to name.
		 */
		if (name[cknamelen] != '/')
			continue;
			
		if (strncmp(name, ckname, cknamelen) != 0)
			continue;

		/* Found a match but keep looking for an exact match. */
		match = -1;
	}

	return(match);
}


/*
 * restoreFile
 *   Restores the specified file.
 *
 * Parameters:
 *   info (input)     - restore info.
 *   name (input)     - name of file being restored.
 *   fileStat (input) - file stat data.
 *
 * Returns:
 *  -1 - error reading file dump data.
 *   0 - error creating file or setting attributes.
 *   1 - file successfully restored.
 */
static int
restoreFile(RestoreInfo*	info,
			char*			name,
			struct stat*	fileStat)
{
	char				path[MAXPATHLEN+1];
	NdmpdModuleParams*	modParams = info->params->modParams;

	if (strlen(name) + strlen(info->destDir) > MAXPATHLEN)
	{
		(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
							  "Restore: ERROR: MAXPATHLEN exceeded for: %s%s.\n",
							  info->destDir, name);
		return(discardFile(info, name, fileStat));
	}
		
	/*
	 * Remove leading ./
	 * This is not really necessary but is done so that the file names
	 * in error messages don't contain embedded /./
	 */
	if (name[0] == '.' && name[1] == '/')
		name += 2;
	else if (name[0] == '.')
		name++;

	strcpy(path, info->destDir);
	strcat(path, name);
	
	/*
	 * Don't overwrite files.
	 * This is enforced mostly to prevent buggy code from
	 * destroying the filesystem.
	 * It also simplifies the code since since existing files
	 * don't have to be dealt with. This is especially a problem if
	 * the file exists and is of a different type than the file being restored.
	 */
	if (access(path, F_OK) == 0)
	{
		(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
							  "Restore: ERROR: file exists: %s.\n",
							  path);
		return(discardFile(info, path, fileStat));
	}
	
	/*
	 * For direct access restores, the parent directories only get
	 * created if explictly specified in the name list so create
	 * them here if they do not already exist.
	 */
	if (info->direct && (fileStat->st_mode & S_IFMT) != S_IFDIR)
	{
		char*	p = strrchr(path, '/');
		if (p != 0 && p != path)
		{
			*p = '\0';
			if (access(path, F_OK) != 0)
			{
				if (mkdirp(path, fileStat->st_mode&S_IAMB) < 0)
				{
					(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
										  "Restore: ERROR: creating directory: %s: %s.\n",
										  path, strerror(errno));
					*p = '/';
					return(0);
				}
			}
			
			*p = '/';
		}
	}
	
	switch (fileStat->st_mode & S_IFMT)
	{
		case S_IFDIR:
		{
			if (mkdirp(path, fileStat->st_mode&S_IAMB) < 0)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: creating directory: %s: %s.\n",
									  path, strerror(errno));
				return(0);
			}
			break;
		}
		
		case S_IFIFO:
		case S_IFBLK:
		case S_IFCHR:
		{
			if (mknod(path,
					  fileStat->st_mode,
					  fileStat->st_dev) < 0)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: creating file: %s: %s.\n",
									  path, strerror(errno));
				return(0);
			}
			break;
		}

		case S_IFREG:
		{
			int		fd;
			caddr_t	addr;

			if ((fd = open(path, O_RDWR|O_CREAT,
						   fileStat->st_mode&S_IAMB)) < 0)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: creating file: %s: %s.\n",
									  path, strerror(errno));
				return(discardFile(info, path, fileStat));
			}

			/* Set the file length so mmap works. */
			if (ftruncate(fd, fileStat->st_size) < 0)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: setting file size: %s: %s.\n",
									  name, strerror(errno));
				(void)close(fd);
				return(discardFile(info, path, fileStat));
			}
			
			if (fileStat->st_size == 0)
			{
				close(fd);
				break;
			}
			
			/* Map in the file. */
			addr = mmap(0, fileStat->st_size, PROT_WRITE, MAP_SHARED,
						fd, 0);
			if (addr == MAP_FAILED)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: mapping file: %s: %s.\n",
									  path, strerror(errno));
				(void)close(fd);
				return(discardFile(info, path, fileStat));
			}

			/* Read the file data into the file via the mapped address. */
			if ((*modParams->readFunc)(modParams->daemonCookie,
									   addr, fileStat->st_size) < 0)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: reading file data: %s: %s.\n",
								   path, strerror(errno));
				(void)munmap(addr, fileStat->st_size);
				(void)close(fd);
				return(-1);
			}
			
			modParams->stats->bytesProcessed += fileStat->st_size;
			(void)munmap(addr, fileStat->st_size);
			(void)close(fd);
			break;
		}
		
		case S_IFLNK:
		{
			char	linkName[MAXPATHLEN];
			
			/*
			 * Read the link name.
			 */
			if ((*modParams->readFunc)(modParams->daemonCookie,
									   (char*)linkName,
									   fileStat->st_size) < 0)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: reading file data: %s: %s.\n",
									  path, strerror(errno));
				return(-1);
			}

			modParams->stats->bytesProcessed += fileStat->st_size;
			linkName[fileStat->st_size] = '\0';
			
			if (symlink(linkName, path) < 0)
			{
				(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									  "Restore: ERROR: creating symbolic link: %s: %s.\n",
									  path, strerror(errno));
				return(0);
			}
			
			break;
		}
		
		default:
		{
			(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
								  "Restore: ERROR: unsupported file type(0%o): %s.\n",
								  fileStat->st_mode&S_IFMT, path);
			return(0);
		}
	}

	if (info->setUidGid == TRUE)
	{
		/*
		 * Set file owner and group.
		 */
		if (chown(path, fileStat->st_uid, fileStat->st_gid) < 0)
		{
			(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
									 "Restore: ERROR: setting uid/gid: %s.\n",
									 path);
			return(0);
		}
	}
	
	return(1);
}


/*
 * discardFile
 *   Read and discard file data.
 *
 * Parameters:
 *   info (input)     - restore info.
 *   name (input)     - file name.
 *   size (input)     - file size.
 *
 * Returns:
 *   -1 - error reading file data.
 *    0 - success.
 */
static int
discardFile(RestoreInfo*	info,
			char*			name,
			struct stat*	fileStat)
{
	int		fd;
	caddr_t	addr;
	NdmpdModuleParams*	modParams = (NdmpdModuleParams*) info->params->modParams;
	
#if 0
	/*
	 * No need to discard if direct access restore since seeking
	 * is done before reading each file.
	 */
	if (info->direct == TRUE)
		return(0);
#endif
	
	/*
	 * Only regular files and symbolic link files have
	 * data that needs to be discarded.
	 */
	if ((fileStat->st_mode & S_IFMT) != S_IFREG &&
		(fileStat->st_mode & S_IFMT) != S_IFLNK)
		return(0);
	
	if (fileStat->st_size == 0)
		return(0);
	
	if ((fd = open("/dev/zero", O_RDWR)) < 0)
	{
		(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
								 "Restore: ERROR: opening /dev/zero: %s.\n",
								 strerror(errno));
		return(-1);
	}

	addr = mmap(0, fileStat->st_size, PROT_WRITE, MAP_PRIVATE, fd, 0);
	if (addr == MAP_FAILED)
	{
		(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
								 "Restore: ERROR: mapping /dev/zero: %s.\n",
								 strerror(errno));
		(void)close(fd);
		return(-1);
	}

	/* Read the file data. */
	if ((*modParams->readFunc)(modParams->daemonCookie,
								  addr, fileStat->st_size) < 0)
	{
		(*modParams->logFunc)(modParams->daemonCookie, NDMP_LOG_NORMAL, 0,
								 "Restore: ERROR: reading file data: %s: %s.\n",
								 name, strerror(errno));
		(void)munmap(addr, fileStat->st_size);
		(void)close(fd);
		return(-1);
	}
			
	modParams->stats->bytesProcessed += fileStat->st_size;
	(void)munmap(addr, fileStat->st_size);
	(void)close(fd);
	return(0);
}