env_universal_common.cpp

/**
   \file env_universal_common.c

   The utility library for universal variables. Used both by the
   client library and by the daemon.

*/
#include "config.h"


#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <pwd.h>
#include <errno.h>
#include <sys/stat.h>
#include <dirent.h>
#include <wctype.h>
#include <iconv.h>

#include <errno.h>
#include <locale.h>
#include <dirent.h>
#include <signal.h>
#include <sys/stat.h>
#include <map>

#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif

#include "fallback.h"
#include "util.h"

#include "common.h"
#include "wutil.h"
#include "env_universal_common.h"

/**
   Non-wide version of the set command
*/
#define SET_MBS "SET"

/**
   Non-wide version of the set_export command
*/
#define SET_EXPORT_MBS "SET_EXPORT"

/**
   Non-wide version of the erase command
*/
#define ERASE_MBS "ERASE"

/**
   Non-wide version of the barrier command
*/
#define BARRIER_MBS "BARRIER"

/**
   Non-wide version of the barrier_reply command
*/
#define BARRIER_REPLY_MBS "BARRIER_REPLY"

/**
   Error message
*/
#define PARSE_ERR L"Unable to parse universal variable message: '%ls'"

/**
   ERROR string for internal buffered reader
*/
#define ENV_UNIVERSAL_ERROR 0x100

/**
   EAGAIN string for internal buffered reader
*/
#define ENV_UNIVERSAL_AGAIN 0x101

/**
   EOF string for internal buffered reader
*/
#define ENV_UNIVERSAL_EOF   0x102

/**
   A variable entry. Stores the value of a variable and whether it
   should be exported. Obviously, it needs to be allocated large
   enough to fit the value string.
*/
typedef struct var_uni_entry
{
	int exportv; /**< Whether the variable should be exported */
	wcstring val; /**< The value of the variable */
	var_uni_entry():exportv(0), val() { }
}
var_uni_entry_t;


static void parse_message( wchar_t *msg,
			   connection_t *src );

/**
   The table of all universal variables
*/
typedef std::map<wcstring, var_uni_entry_t*> env_var_table_t;
env_var_table_t env_universal_var;

/**
   Callback function, should be called on all events
*/
static void (*callback)( fish_message_type_t type,
				  const wchar_t *key, 
				  const wchar_t *val );

/**
   List of names for the UTF-8 character set.
 */
static const char *iconv_utf8_names[]=
  {
    "utf-8", "UTF-8",
    "utf8", "UTF8",
    0
  }
  ;

/**
    List of wide character names, undefined byte length.
 */
static const char *iconv_wide_names_unknown[]=
  {
    "wchar_t", "WCHAR_T", 
    "wchar", "WCHAR", 
    0
  }
  ;

/**
   List of wide character names, 4 bytes long.
 */
static const char *iconv_wide_names_4[]=
  {
    "wchar_t", "WCHAR_T", 
    "wchar", "WCHAR", 
    "ucs-4", "UCS-4", 
    "ucs4", "UCS4", 
    "utf-32", "UTF-32", 
    "utf32", "UTF32", 
    0
  }
  ;

/**
   List of wide character names, 2 bytes long.
 */
static const char *iconv_wide_names_2[]=
  {
    "wchar_t", "WCHAR_T", 
    "wchar", "WCHAR", 
    "ucs-2", "UCS-2", 
    "ucs2", "UCS2", 
    "utf-16", "UTF-16", 
    "utf16", "UTF16", 
    0
  }
  ;

template<class T>
class sloppy {}; 

static size_t hack_iconv(iconv_t cd, const char * const* inbuf, size_t *inbytesleft, char **outbuf, size_t *outbytesleft)
{
    /* FreeBSD has this prototype: size_t iconv (iconv_t, const char **...)
       OS X and Linux this one: size_t iconv (iconv_t, char **...)
       AFAIK there's no single type that can be passed as both char ** and const char **.
       Therefore, we let C++ figure it out, by providing a struct with an implicit conversion to both char** and const char **.
    */
    struct sloppy_char
    {
        const char * const * t;
        operator char** () const { return (char **)t; }
        operator const char** () const { return (const char**)t; }
    } slop_inbuf = {inbuf};
    
    return iconv( cd, slop_inbuf, inbytesleft, outbuf, outbytesleft );
}

/**
   Convert utf-8 string to wide string
 */
static wchar_t *utf2wcs( const char *in )
{
	iconv_t cd=(iconv_t) -1;
	int i,j;

	wchar_t *out;

	/*
	  Try to convert to wchar_t. If that is not a valid character set,
	  try various names for ucs-4. We can't be sure that ucs-4 is
	  really the character set used by wchar_t, but it is the best
	  assumption we can make.
	*/
	const char **to_name=0;

	switch (sizeof (wchar_t))
	{
	
		case 2:
			to_name = iconv_wide_names_2;
			break;

		case 4:
			to_name = iconv_wide_names_4;
			break;
			
		default:
			to_name = iconv_wide_names_unknown;
			break;
	}
	

	/*
	  The line protocol fish uses is always utf-8. 
	*/
	const char **from_name = iconv_utf8_names;

	size_t in_len = strlen( in );
	size_t out_len =  sizeof( wchar_t )*(in_len+2);
	size_t nconv;
	char *nout;
	
	out = (wchar_t *)malloc( out_len );
	nout = (char *)out;

	if( !out )
		return 0;
	
	for( i=0; to_name[i]; i++ )
	{
		for( j=0; from_name[j]; j++ )
		{
			cd = iconv_open ( to_name[i], from_name[j] );

			if( cd != (iconv_t) -1)
			{
				goto start_conversion;
				
			}
		}
	}

  start_conversion:

	if (cd == (iconv_t) -1)
	{
		/* Something went wrong.  */
		debug( 0, L"Could not perform utf-8 conversion" );		
		if(errno != EINVAL)
			wperror( L"iconv_open" );
		
		/* Terminate the output string.  */
		free(out);
		return 0;		
	}
	
    /* FreeBSD has this prototype: size_t iconv (iconv_t, const char **...)
       OS X and Linux this one: size_t iconv (iconv_t, char **...)
       AFAIK there's no single type that can be passed as both char ** and const char **.
       So we cast the function pointer instead (!)
    */
    nconv = hack_iconv( cd, &in, &in_len, &nout, &out_len );
		
	if (nconv == (size_t) -1)
	{
		debug( 0, L"Error while converting from utf string" );
		return 0;
	}
	     
	*((wchar_t *) nout) = L'\0';

	/*
		Check for silly iconv behaviour inserting an bytemark in the output
		string.
	 */
	if (*out == L'\xfeff' || *out == L'\xffef' || *out == L'\xefbbbf')
	{
		wchar_t *out_old = out;
		out = wcsdup(out+1);
		if (! out )
		{
			debug(0, L"FNORD!!!!");
			free( out_old );
			return 0;
		}
		free( out_old );
	}
	
	
	if (iconv_close (cd) != 0)
		wperror (L"iconv_close");
	
	return out;	
}



/**
   Convert wide string to utf-8
 */
static char *wcs2utf( const wchar_t *in )
{
	iconv_t cd=(iconv_t) -1;
	int i,j;
	
	char *char_in = (char *)in;
	char *out;

	/*
	  Try to convert to wchar_t. If that is not a valid character set,
	  try various names for ucs-4. We can't be sure that ucs-4 is
	  really the character set used by wchar_t, but it is the best
	  assumption we can make.
	*/
	const char **from_name=0;

	switch (sizeof (wchar_t))
	{
	
		case 2:
			from_name = iconv_wide_names_2;
			break;

		case 4:
			from_name = iconv_wide_names_4;
			break;
			
		default:
			from_name = iconv_wide_names_unknown;
			break;
	}

	const char **to_name = iconv_utf8_names;

	size_t in_len = wcslen( in );
	size_t out_len =  sizeof( char )*( (MAX_UTF8_BYTES*in_len)+1);
	size_t nconv;
	char *nout;
	
	out = (char *)malloc( out_len );
	nout = (char *)out;
	in_len *= sizeof( wchar_t );

	if( !out )
		return 0;
	
	for( i=0; to_name[i]; i++ )
	{
		for( j=0; from_name[j]; j++ )
		{
			cd = iconv_open ( to_name[i], from_name[j] );
			
			if( cd != (iconv_t) -1)
			{
				goto start_conversion;
				
			}
		}
	}

  start_conversion:

	if (cd == (iconv_t) -1)
	{
		/* Something went wrong.  */
		debug( 0, L"Could not perform utf-8 conversion" );		
		if(errno != EINVAL)
			wperror( L"iconv_open" );
		
		/* Terminate the output string.  */
		free(out);
		return 0;		
	}
	
    nconv = hack_iconv( cd, &char_in, &in_len, &nout, &out_len );
	

	if (nconv == (size_t) -1)
	{
		debug( 0, L"%d %d", in_len, out_len );
		debug( 0, L"Error while converting from to string" );
		return 0;
	}
	     
	*nout = '\0';
	
	if (iconv_close (cd) != 0)
		wperror (L"iconv_close");
	
	return out;	
}



void env_universal_common_init( void (*cb)(fish_message_type_t type, const wchar_t *key, const wchar_t *val ) )
{
	callback = cb;
}


void env_universal_common_destroy()
{
	env_var_table_t::iterator iter;
	
	for(iter = env_universal_var.begin(); iter != env_universal_var.end(); ++iter)
	{	
		var_uni_entry_t* value = iter->second;
		delete value;
	}
}

/**
   Read one byte of date form the specified connection
 */
static int read_byte( connection_t *src )
{

	if( src->buffer_consumed >= src->buffer_used )
	{

		ssize_t res = read( src->fd, src->buffer, ENV_UNIVERSAL_BUFFER_SIZE );
		
//		debug(4, L"Read chunk '%.*s'", res, src->buffer );
		
		if( res < 0 )
		{

			if( errno == EAGAIN ||
				errno == EINTR )
			{
				return ENV_UNIVERSAL_AGAIN;
			}
		
			return ENV_UNIVERSAL_ERROR;

		}
		
		if( res == 0 )
		{
			return ENV_UNIVERSAL_EOF;
		}
		
		src->buffer_consumed = 0;
		src->buffer_used = res;
	}
	
	return src->buffer[src->buffer_consumed++];

}


void read_message( connection_t *src )
{
	while( 1 )
	{
		
		int ib = read_byte( src );
		char b;
		
		switch( ib )
		{
			case ENV_UNIVERSAL_AGAIN:
			{
				return;
			}

			case ENV_UNIVERSAL_ERROR:
			{
				debug( 2, L"Read error on fd %d, set killme flag", src->fd );
				if( debug_level > 2 )
					wperror( L"read" );
				src->killme = 1;
				return;
			}

			case ENV_UNIVERSAL_EOF:
			{
				src->killme = 1;
				debug( 3, L"Fd %d has reached eof, set killme flag", src->fd );
				if( src->input.size() > 0 )
				{
					char c = 0;
					src->input.push_back(c);
					debug( 1, 
						   L"Universal variable connection closed while reading command. Partial command recieved: '%s'", 
						   &src->input.at(0));
				}
				return;
			}
		}
		
		b = (char)ib;
		
		if( b == '\n' )
		{
			wchar_t *msg;
			
			b = 0;
            src->input.push_back(b);
			
			msg = utf2wcs( &src->input.at(0) );
			
			/*
			  Before calling parse_message, we must empty reset
			  everything, since the callback function could
			  potentially call read_message.
			*/
			src->input.clear();
			
			if( msg )
			{
				parse_message( msg, src );	
			}
			else
			{
				debug( 0, _(L"Could not convert message '%s' to wide character string"), &src->input.at(0) );
			}
			
			free( msg );
			
		}
		else
		{
            src->input.push_back(b);
		}
	}
}

/**
   Remove variable with specified name
*/
void env_universal_common_remove( const wcstring &name )
{
	env_var_table_t::iterator result =  env_universal_var.find(name);
	if (result != env_universal_var.end())
	{
		var_uni_entry_t* v = result->second;		
		env_universal_var.erase(result);
		delete v;
	}
}

/**
   Test if the message msg contains the command cmd
*/
static int match( const wchar_t *msg, const wchar_t *cmd )
{
	size_t len = wcslen( cmd );
	if( wcsncasecmp( msg, cmd, len ) != 0 )
		return 0;

	if( msg[len] && msg[len]!= L' ' && msg[len] != L'\t' )
		return 0;
	
	return 1;
}

void env_universal_common_set( const wchar_t *key, const wchar_t *val, int exportv )
{
	var_uni_entry_t *entry;

	CHECK( key, );
	CHECK( val, );
	
	entry = new var_uni_entry_t;

	entry->exportv=exportv;
	entry->val = val;
	env_universal_common_remove( key );
	
    env_universal_var[key] = entry;
	if( callback )
	{
		callback( exportv?SET_EXPORT:SET, key, val );
	}
}


/**
   Parse message msg
*/
static void parse_message( wchar_t *msg,
						   connection_t *src )
{
//	debug( 3, L"parse_message( %ls );", msg );
	
	if( msg[0] == L'#' )
		return;
	
	if( match( msg, SET_STR ) || match( msg, SET_EXPORT_STR ))
	{
		wchar_t *name, *tmp;
		int exportv = match( msg, SET_EXPORT_STR );
		
		name = msg+(exportv?wcslen(SET_EXPORT_STR):wcslen(SET_STR));
		while( wcschr( L"\t ", *name ) )
			name++;
		
		tmp = wcschr( name, L':' );
		if( tmp )
		{
			wchar_t *key;
			wchar_t *val;
			
			key = (wchar_t *)malloc( sizeof( wchar_t)*(tmp-name+1));
			memcpy( key, name, sizeof( wchar_t)*(tmp-name));
			key[tmp-name]=0;
			
			val = tmp+1;
			val = unescape( val, 0 );
			
			if (key && val)
			    env_universal_common_set( key, val, exportv );
			
			free( val );
			free( key );
		}
		else
		{
			debug( 1, PARSE_ERR, msg );
		}			
	}
	else if( match( msg, ERASE_STR ) )
	{
		wchar_t *name, *tmp;
		
		name = msg+wcslen(ERASE_STR);
		while( wcschr( L"\t ", *name ) )
			name++;
		
		tmp = name;
		while( iswalnum( *tmp ) || *tmp == L'_')
			tmp++;
		
		*tmp = 0;
		
		if( !wcslen( name ) )
		{
			debug( 1, PARSE_ERR, msg );
		}

		env_universal_common_remove( name );
		
		if( callback )
		{
			callback( ERASE, name, 0 );
		}
	}
	else if( match( msg, BARRIER_STR) )
	{
		message_t *msg = create_message( BARRIER_REPLY, 0, 0 );
		msg->count = 1;
        src->unsent->push(msg);
		try_send_all( src );
	}
	else if( match( msg, BARRIER_REPLY_STR ) )
	{
		if( callback )
		{
			callback( BARRIER_REPLY, 0, 0 );
		}
	}
	else
	{
		debug( 1, PARSE_ERR, msg );
	}		
}

/**
   Attempt to send the specified message to the specified file descriptor

   \return 1 on sucess, 0 if the message could not be sent without blocking and -1 on error
*/
static int try_send( message_t *msg,
					 int fd )
{

	debug( 3,
		   L"before write of %d chars to fd %d", msg->body.size(), fd );

	ssize_t res = write( fd, msg->body.c_str(), msg->body.size() );

	if( res != -1 )
	{
		debug( 4, L"Wrote message '%s'", msg->body.c_str() );
	}
	else
	{
		debug( 4, L"Failed to write message '%s'", msg->body.c_str() );
	}
	
	if( res == -1 )
	{
		switch( errno )
		{
			case EAGAIN:
				return 0;
				
			default:
				debug( 2,
					   L"Error while sending universal variable message to fd %d. Closing connection",
					   fd );
				if( debug_level > 2 )
					wperror( L"write" );
				
				return -1;
		}		
	}
	msg->count--;
	
	if( !msg->count )
	{
		delete msg;
	}
	return 1;
}

void try_send_all( connection_t *c )
{
/*	debug( 3,
		   L"Send all updates to connection on fd %d", 
		   c->fd );*/
	while( !c->unsent->empty() )
	{
		switch( try_send( c->unsent->front(), c->fd ) )
		{
			case 1:
				c->unsent->pop();
				break;
				
			case 0:
				debug( 4,
					   L"Socket full, send rest later" );	
				return;
								
			case -1:
				c->killme = 1;
				return;
		}
	}
}

/* The universal variable format has some funny escaping requirements; here we try to be safe */
static bool is_universal_safe_to_encode_directly(wchar_t c)
{
    if (c < 32 || c > 128)
        return false;
    
    return iswalnum(c) || wcschr(L"/", c);
}

/**
   Escape specified string
 */
static wcstring full_escape( const wchar_t *in )
{
	wcstring out;
	for( ; *in; in++ )
	{
        wchar_t c = *in;
        if (is_universal_safe_to_encode_directly(c))
        {
            out.push_back(c);
        }
		else if (c < 256)
		{
			append_format(out, L"\\x%.2x", c);
		}
		else if (c < 65536)
		{
			append_format(out, L"\\u%.4x", c);
		}
		else
		{
			append_format(out, L"\\U%.8x", c);
		}
	}
	return out;
}

/* Sets the body of a message to the null-terminated list of null terminated const char *. */
void set_body(message_t *msg, ...)
{
    /* Start by counting the length of all the strings */
    size_t body_len = 0;
    const char *arg;
    va_list arg_list;
	va_start(arg_list, msg);
	while ((arg = va_arg(arg_list, const char *)) != NULL)
		body_len += strlen(arg);
	va_end(arg_list);
    
    /* Reserve that length in the string */
    msg->body.reserve(body_len + 1); //+1 for trailing NULL? Do I need that?
    
    /* Set the string contents */
	va_start(arg_list, msg);
	while ((arg = va_arg(arg_list, const char *)) != NULL)
		msg->body.append(arg);
	va_end(arg_list);
}

/* Returns an instance of message_t allocated via new */
message_t *create_message( fish_message_type_t type,
                          const wchar_t *key_in,
                          const wchar_t *val_in )
{
	message_t *msg = new message_t;
    msg->count = 0;
	
	char *key=0;
    
    //	debug( 4, L"Crete message of type %d", type );
	
	if( key_in )
	{
		if( wcsvarname( key_in ) )
		{
			debug( 0, L"Illegal variable name: '%ls'", key_in );
			return 0;
		}
		
		key = wcs2utf(key_in);
		if( !key )
		{
			debug( 0,
                  L"Could not convert %ls to narrow character string",
                  key_in );
			return 0;
		}
	}
	
	
	switch( type )
	{
		case SET:
		case SET_EXPORT:
		{
			if( !val_in )
			{
				val_in=L"";
			}
			
			wcstring esc = full_escape( val_in );
			char *val = wcs2utf(esc.c_str());
            set_body(msg, (type==SET?SET_MBS:SET_EXPORT_MBS), " ", key, ":", val, "\n", NULL);
			free( val );
			
			break;
		}
            
		case ERASE:
		{
            set_body(msg, ERASE_MBS, " ", key, "\n", NULL);
            break;
		}
            
		case BARRIER:
		{
            set_body(msg, BARRIER_MBS, "\n", NULL);
			break;
		}
            
		case BARRIER_REPLY:
		{
            set_body(msg, BARRIER_REPLY_MBS, "\n", NULL);
			break;
		}
            
		default:
		{
			debug( 0, L"create_message: Unknown message type" );
		}
	}
    
	free( key );
    
    //	debug( 4, L"Message body is '%s'", msg->body );
    
	return msg;	
}

/**
	Put exported or unexported variables in a string list
*/	
void env_universal_common_get_names( wcstring_list_t &lst,
									 int show_exported,
									 int show_unexported )
{
	env_var_table_t::const_iterator iter;
	for (iter = env_universal_var.begin(); iter != env_universal_var.end(); ++iter)
	{
		const wcstring& key = iter->first;
		const var_uni_entry_t *e = iter->second; 
		if( ( e->exportv && show_exported) || 
		( !e->exportv && show_unexported) )
		{
    	    lst.push_back(key);
		}
	
	} 

}


wchar_t *env_universal_common_get( const wcstring &name )
{
	env_var_table_t::const_iterator result = env_universal_var.find(name);

	if (result != env_universal_var.end() )
	{
		const var_uni_entry_t *e = result->second;
		if( e )
			return const_cast<wchar_t*>(e->val.c_str());
	}

	return 0;	
}

int env_universal_common_get_export( const wcstring &name )
{
	env_var_table_t::const_iterator result = env_universal_var.find(name);
	if (result != env_universal_var.end() )
	{
		const var_uni_entry_t *e = result->second;
		if (e != NULL)
			return e->exportv;
	}
	return 0;
}

void enqueue_all( connection_t *c )
{
	env_var_table_t::const_iterator iter;

	for (iter = env_universal_var.begin(); iter != env_universal_var.end(); ++iter)
	{
		const wcstring &key = iter->first;
		const var_uni_entry_t *val = iter->second;
	
		message_t *msg = create_message( val->exportv?SET_EXPORT:SET, key.c_str(), val->val.c_str() );
		msg->count=1;
		c->unsent->push(msg);
	}

	try_send_all( c );
}


void connection_init( connection_t *c, int fd )
{
	memset (c, 0, sizeof (connection_t));
	c->fd = fd;
    c->unsent = new std::queue<message_t *>;
	c->buffer_consumed = c->buffer_used = 0;	
}

void connection_destroy( connection_t *c)
{
    if (c->unsent) delete c->unsent;

	/*
	  A connection need not always be open - we only try to close it
	  if it is open.
	*/
	if( c->fd >= 0 )
	{
		if( close( c->fd ) )
		{
			wperror( L"close" );
		}
	}
}