Added the code for looking up files with names like 'file,,x'.

The user can now request files with special names like 'file,,x'
and the proxy will start the translator 'x' on file 'file' and
return the port to the user. If 'x' is not an absolute path,
the default prefix '/hurd/' is added to it.

3 files changed, 471 insertions, 62 deletions

diff --git a/lnode.c b/lnode.c
index 285d947bb..406b7b4f5 100644
--- a/lnode.c
+++ b/lnode.c
@@ -303,3 +303,70 @@ lnode_uninstall
 		node->next->prevp = &node->next;
 	}/*lnode_uninstall*/
 /*----------------------------------------------------------------------------*/
+/*Constructs a list of translators that were set on the ancestors of `node`*/
+error_t
+lnode_list_translators
+	(
+	lnode_t * node,
+	char ** trans,	/*the malloced list of 0-separated strings*/
+	size_t * ntrans	/*the number of elements in `trans`*/
+	)
+	{
+	/*The size of block of memory for the list of translators*/
+	size_t sz = 0;
+	
+	/*Used for tracing the lineage of `node`*/
+	lnode_t * ln = node;
+	
+	/*Used in computing the lengths of lists of translators in every node
+		we will go through and for constructing the final list of translators*/
+	char * p;
+	
+	/*The current position in *data (used in filling out the list of
+		translators)*/
+	char * transp;
+	
+	/*The length of the current translator name*/
+	size_t complen;
+	
+	size_t i;
+	
+	/*Trace the lineage of the `node` (including itself) and compute the
+		total length of the list of translators*/
+	for(; ln; sz += ln->translen, ln = ln->dir);
+	
+	/*Try to allocate a block of memory sufficient for storing the list of
+		translators*/
+	*trans = malloc(sz);
+	if(!*trans)
+		return ENOMEM;
+	
+	/*No translators at first*/
+	*ntrans = 0;
+	
+	/*Again trace the lineage of the `node` (including itself)*/
+	for(transp = *trans + sz, ln = node; ln; ln = ln->dir)
+		{
+		/*Go through each translator name in the list of names*/
+		for(i = 0, p = ln->trans + ln->translen - 2; i < ln->ntrans; ++i)
+			{
+			/*position p at the beginning of the current component and
+				compute its length at the same time*/
+			for(complen = 0; *p; --p, ++complen);
+			--p;
+			
+			/*move the current position backwards*/
+			transp -= complen + 1;
+
+			/*copy the current translator name into the list*/
+			strcpy(transp, p + 2);
+			
+			/*we've got another translator*/
+			++*ntrans;
+			}
+		}
+		
+	/*Everything OK*/
+	return 0;
+	}/*lnode_list_translators*/
+/*----------------------------------------------------------------------------*/
diff --git a/lnode.h b/lnode.h
index 7c42c8d4f..9ca1ef2c5 100644
--- a/lnode.h
+++ b/lnode.h
@@ -48,6 +48,17 @@ struct lnode
 	/*the full path to the lnode*/
 	char * path;
 	
+	/*the malloced set of translators which have to be stacked upon this node
+	  and upon its children; the corresponding translators will have to decide
+	  on their own whether to accept directories or not*/
+	char * trans;
+	
+	/*the number of translators listed in `translators`*/
+	size_t ntrans;
+	
+	/*the length of the list of translators (in bytes)*/
+	size_t translen;
+
 	/*the associated flags*/
 	int flags;
 	
@@ -140,4 +151,13 @@ lnode_uninstall
 	lnode_t * node
 	);
 /*----------------------------------------------------------------------------*/
+/*Constructs a list of translators that were set on the ancestors of `node`*/
+error_t
+lnode_list_translators
+	(
+	lnode_t * node,
+	char ** trans,	/*the malloced list of 0-separated strings*/
+	size_t * ntrans	/*the number of elements in `trans`*/
+	);
+/*----------------------------------------------------------------------------*/
 #endif /*__LNODE_H__*/
diff --git a/nsmux.c b/nsmux.c
index 8f068f2e1..d7f89002c 100644
--- a/nsmux.c
+++ b/nsmux.c
@@ -558,41 +558,8 @@ netfs_attempt_lookup
 		return err;
 		}
 
-	/*Try to lookup the given file in the underlying directory*/
-	mach_port_t p = file_name_lookup_under(dir->nn->port, name, 0, 0);
-	
-	/*If the lookup failed*/
-	if(p == MACH_PORT_NULL)
-		{
-		/*unlock the directory*/
-		mutex_unlock(&dir->lock);
-
-		/*no such entry*/
-		return ENOENT;
-		}
-
-	/*Obtain the stat information about the file*/
-	io_statbuf_t stat;
-	err = io_stat(p, &stat);
-	
-	/*Deallocate the obtained port*/
-	PORT_DEALLOC(p);
-
-	/*If this file is not a directory*/
-	if(err || !S_ISDIR(stat.st_mode))
-		{
-		/*do not set the port*/
-		p = MACH_PORT_NULL;
-		}
-	else
-		{
-		/*lookup the port with the right to read the contents of the directory*/
-		p = file_name_lookup_under(dir->nn->port, name, O_READ | O_DIRECTORY, 0);
-		if(p == MACH_PORT_NULL)
-			{
-			return EBADF; /*not enough rights?*/
-			}
-		}
+	/*The port to the requested file*/
+	mach_port_t p;
 
 	/*The lnode corresponding to the entry we are supposed to fetch*/
 	lnode_t * lnode;
@@ -626,53 +593,394 @@ netfs_attempt_lookup
 		mutex_unlock(&dir->lock);
 		}/*finalize*/
 
-	/*Try to find an lnode called `name` under the lnode corresponding to `dir`*/
-	err = lnode_get(dir->nn->lnode, name, &lnode);
+	/*Performs a usual lookup*/
+	error_t
+	lookup
+		(
+		char * name	/*lookup this*/
+		)
+		{
+		/*Try to lookup the given file in the underlying directory*/
+		p = file_name_lookup_under(dir->nn->port, name, 0, 0);
 	
-	/*If such an entry does not exist*/
-	if(err == ENOENT)
+		/*If the lookup failed*/
+		if(p == MACH_PORT_NULL)
+			{
+			/*unlock the directory*/
+			mutex_unlock(&dir->lock);
+
+			/*no such entry*/
+			return ENOENT;
+			}
+
+		/*Obtain the stat information about the file*/
+		io_statbuf_t stat;
+		err = io_stat(p, &stat);
+	
+		/*Deallocate the obtained port*/
+		PORT_DEALLOC(p);
+
+		/*If this file is not a directory*/
+		if(err || !S_ISDIR(stat.st_mode))
+			{
+			/*do not set the port*/
+			p = MACH_PORT_NULL;
+			}
+		else
+			{
+			/*lookup the port with the right to read the contents of the directory*/
+			p = file_name_lookup_under(dir->nn->port, name, O_READ | O_DIRECTORY, 0);
+			if(p == MACH_PORT_NULL)
+				{
+				return EBADF; /*not enough rights?*/
+				}
+			}
+
+		/*Try to find an lnode called `name` under the lnode corresponding to `dir`*/
+		err = lnode_get(dir->nn->lnode, name, &lnode);
+	
+		/*If such an entry does not exist*/
+		if(err == ENOENT)
+			{
+			/*create a new lnode with the supplied name*/
+			err = lnode_create(name, &lnode);
+			if(err)
+				{
+				finalize();
+				return err;
+				}
+		
+			/*install the new lnode into the directory*/
+			lnode_install(dir->nn->lnode, lnode);
+			}
+		else
+			{
+			/*TODO: Remove the code from here and put it into the caller block,
+				so that we can decide there whether to remove translators and
+				*which* ones to remove*/
+
+			/*free the list of translators associated with this node, if
+				such a list exists*/
+			if(lnode->trans)
+				{
+				free(lnode->trans);
+				lnode->trans = NULL;
+				lnode->ntrans = lnode->translen = 0;
+				}
+			}
+	
+		/*Obtain the node corresponding to this lnode*/
+		err = ncache_node_lookup(lnode, node);
+	
+		/*Remove an extra reference from the lnode*/
+		lnode_ref_remove(lnode);
+	
+		/*If the lookup in the cache failed*/
+		if(err)
+			{
+			/*stop*/
+			finalize();
+			return err;
+			}
+
+		/*Store the port in the node*/
+		(*node)->nn->port = p;
+
+		/*Construct the full path to the node*/
+		err = lnode_path_construct(lnode, NULL);
+		if(err)
+			{
+			finalize();
+			return err;
+			}
+	
+		/*Now the node is up-to-date*/
+		(*node)->nn->flags = FLAG_NODE_ULFS_UPTODATE;
+
+		/*Everything OK here*/
+		return 0;
+		}/*lookup*/
+
+	/*The position of ',,' in the name*/
+	char * sep;
+	
+	/*A pointer for various operations on strings*/
+	char * str;
+	
+	/*While pairs of commas can still be found in the name*/
+	for(sep = strstr(name, ",,"); sep; sep = strstr(sep, ",,"))
 		{
-		/*create a new lnode with the supplied name*/
-		err = lnode_create(name, &lnode);
+		/*If the separator is situated at the beginning, it is an error*/
+		if(sep == name)
+			{
+			finalize();
+			return ENOENT;
+			}
+
+		/*If current pair of commas is not escaped*/
+		if(*(sep + 2) != ',')
+			/*stop here, we've found what we needed*/
+			break;
+		
+		/*remove the escaping ',' from the string*/
+		for(str = ++sep; *str; str[-1] = *str, ++str);
+		str[-1] = 0;
+		
+		/*skip the current pair of commas*/
+		++sep;
+		}
+	
+	/*If the control sequence has been found present*/
+	if(sep)
+		{
+		/*copy the name*/
+		/*just copy the pointer*/
+		char * name_cpy = /*strdup*/(name);
+		if(!name_cpy)
+			{
+			err = ENOMEM;
+			finalize();
+			return err;
+			}
+			
+		/*move sep to name_cpy*/
+		sep = name_cpy + (sep - name);
+		
+		/*remove the separator from the string*/
+		*(sep++) = 0;
+		*(sep++) = 0;
+		
+		/*try to lookup a node with the specified name*/
+		err = lookup(name_cpy);
 		if(err)
 			{
 			finalize();
 			return err;
 			}
 		
-		/*install the new lnode into the directory*/
-		lnode_install(dir->nn->lnode, lnode);
+		/*duplicate the part of the name containing the list of translators
+			and store the copy in the lnode*/
+		lnode->trans = strdup(sep);
+		if(!lnode->trans)
+			{
+			finalize();
+			return err;
+			}
+
+		/*free the copy of the name*/
+		/*we've just copied the pointer, so don't free it*/
+		/*free(name_cpy);*/
+		
+		/*obtain a pointer to the beginning of the list of translators*/
+		str = lnode->trans;
+		
+		/*used to process escaped commas*/
+		/*char * p;*/
+		
+		/*Go through the list of translators*/
+		for(lnode->ntrans = 0; *str; ++str)
+			{
+			/*Commas are not allowed in translator names*/
+#if 0
+			/*If we are now situated at an escaped comma*/
+			if((*str == '\\') && (str[1] == ','))
+				{
+				/*shift everything left in the string to remove the escaping backslash*/
+				for(p = str; *p; *p = p[1], ++p);
+				
+				/*count a single character and step forward*/
+				++lnode->translen;
+				continue;
+				}
+#endif
+
+			/*If the current character is a comma*/
+			if(*str == ',')
+				{
+				/*make it a separator zero*/
+				*str = 0;
+				
+				/*we have just finished going through a new component*/
+				++lnode->ntrans;
+				}
+				
+			/*take the current character into account*/
+			++lnode->translen;
+			}
+			
+		/*take into consideration the last element in the list,
+			which does not end in a comma and the corresponding terminal 0*/
+		++lnode->ntrans;
+		++lnode->translen;
+		}
+	/*The control sequence ',,' has not been found*/
+	else
+		{
+		/*simply lookup the provided name*/
+		err = lookup(name);
+		if(err)
+			{
+			finalize();
+			return err;
+			}
 		}
 	
-	/*Obtain the node corresponding to this lnode*/
-	err = ncache_node_lookup(lnode, node);
+	/*The list of translators inherited from its ancestors*/
+	char * trans;
 	
-	/*Remove an extra reference from the lnode*/
-	lnode_ref_remove(lnode);
+	/*the number of translators*/
+	size_t ntrans;
 	
-	/*If the lookup in the cache failed*/
+	/*Obtain the list of inherited translators*/
+	err = lnode_list_translators(lnode, &trans, &ntrans);
 	if(err)
 		{
-		/*stop*/
 		finalize();
 		return err;
 		}
 
-	/*Store the port in the node*/
-	(*node)->nn->port = p;
-
-	/*Construct the full path to the node*/
-	err = lnode_path_construct(lnode, NULL);
-	if(err)
+	/*If no translators have to be set*/
+	if(ntrans == 0)
 		{
+		/*we have looked up what we need*/
 		finalize();
-		return err;
+		return 0;
 		}
-	
-	/*Now the node is up-to-date*/
-	(*node)->nn->flags = FLAG_NODE_ULFS_UPTODATE;
 
-	/*Return the result of performing the operations*/
+	int i;
+
+	/*If there is a port open for the current node*/
+	if((*node)->nn->port != MACH_PORT_NULL)
+		{
+		/*close the port, since we will open it when starting translators*/
+		PORT_DEALLOC((*node)->nn->port);
+		}
+
+	/*Opens a port to the file at the request of fshelp_start_translator*/
+	error_t
+	open_port
+		(
+		int flags,
+		mach_port_t * underlying,
+		mach_msg_type_name_t * underlying_type,
+		task_t task,
+		void * cookie	/*some additional information, not used here*/
+		)
+		{
+		/*Lookup the file we are working with*/
+		p = file_name_lookup_under
+			(dir->nn->port, (*node)->nn->lnode->name, flags, 0);
+		if(p == MACH_PORT_NULL)
+			return errno;
+			
+		/*Store the result in the parameters*/
+		*underlying = p;
+		*underlying_type = MACH_MSG_TYPE_COPY_SEND;
+		
+		/*Here everything is OK*/
+		return 0;
+		}/*open_port*/
+
+	/*Adds a "/hurd/" at the beginning of the translator name, if required*/
+	char *
+	put_in_hurd
+		(
+		char * name
+		)
+		{
+		/*If the path to the translator is absolute, return a copy of the name*/
+		/*TODO: A better decision technique on whether we have to add the prefix*/
+		if(name[0] == '/')
+			return strdup(name);
+		
+		/*Compute the length of the name*/
+		size_t len = strlen(name);
+		
+		/*Try to allocate new memory*/
+		char * full = malloc(6/*strlen("/hurd/")*/ + len + 1);
+		if(!full)
+			return NULL;
+		
+		/*Construct the name*/
+		strcpy(full, "/hurd/");
+		strcpy(full + 6, name);
+		full[6 + len] = 0;
+		
+		/*Return the full path*/
+		return full;
+		}/*put_in_hurd*/
+
+	/*A copy (possibly extended) of the name of the translator*/
+	char * ext;
+
+	/*The length of the current component in the list of translators*/
+	size_t complen;
+
+	/*The holders of argz-transformed translator name and arguments*/
+	char * argz = NULL;
+	size_t argz_len = 0;
+
+	/*The control port for the active translator*/
+	mach_port_t active_control;
+
+	/*Go through the list of translators*/
+	for(str = trans, i = 0; i < ntrans; ++i)
+		{
+		/*obtain the length of the current component*/
+		complen = strlen(str);
+		
+		/*obtain a copy (possibly extended) of the name*/
+		ext = put_in_hurd(str);
+		if(!ext)
+			{
+			err = ENOMEM;
+			finalize();
+			return err;
+			}
+		
+		/*TODO: Better argument-parsing?*/
+		
+		/*obtain the argz version of str*/
+		err = argz_create_sep(ext, ' ', &argz, &argz_len);
+		if(err)
+			{
+			finalize();
+			return err;
+			}
+		
+		/*start the translator*/
+		err = fshelp_start_translator
+			(
+			open_port, NULL, argz, argz, argz_len,
+			60000,/*this is the default in settrans*/
+			&active_control
+			);
+		if(err)
+			{
+			finalize();
+			return err;
+			}
+		
+		/*attempt to set a translator on the port opened by the previous call*/
+		err = file_set_translator
+			(
+			p, 0, FS_TRANS_SET, 0, argz, argz_len,
+			active_control, MACH_MSG_TYPE_COPY_SEND
+			);
+		if(err)
+			{
+			finalize();
+			return err;
+			}
+		
+		/*deallocate the port we have just opened*/
+		PORT_DEALLOC(p);
+
+		/*skip the current component*/
+		str += complen + 1;
+		}
+
+	/*Everything OK here*/
 	finalize();
 	return err;
 	}/*netfs_attempt_lookup*/
@@ -981,9 +1289,23 @@ netfs_attempt_read
 		/*store the port in the node*/
 		np->nn->port = p;
 		}
+	
+	/*Obtain a pointer to the first byte of the supplied buffer*/
+	char * buf = data;
+	
+	/*Try to read the requested information from the file*/
+	err = io_read(np->nn->port, &buf, len, offset, *len);
+	
+	/*If some data has been read successfully*/
+	if(!err && (buf != data))
+		{
+		/*copy the data from the buffer into which is has been read into the
+			supplied receiver*/
+		memcpy(data, buf, *len);
 		
-	/*Read the required data from the file*/
-	err = io_read(np->nn->port, (char **)&data, len, offset, *len);
+		/*unmap the new buffer*/
+		munmap(buf, *len);
+		}
 
 	/*Return the result of reading*/
 	return err;