fish-shell/env_universal.c

#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <strings.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <pwd.h>
#include <errno.h>
#include <fcntl.h>
#if HAVE_NCURSES_H
#include <ncurses.h>
#else
#include <curses.h>
#endif
#include <term.h>
#include <signal.h>

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

/**
   Maximum number of times to try to get a new fishd socket
*/

#define RECONNECT_COUNT 32


connection_t env_universal_server;

/**
   Set to 1 after initialization has been performed
*/
static int init = 0;

/**
   The number of attempts to start fishd
*/
static int get_socket_count = 0;

static wchar_t * path;
static wchar_t *user;
static void (*start_fishd)();
static void (*external_callback)( int type, const wchar_t *name, const wchar_t *val );

/**
   Flag set to 1 when a barrier reply is recieved
*/
static int barrier_reply = 0;

void env_universal_barrier();


/**
   Get a socket for reading from the server
*/
static int get_socket( int fork_ok )
{
	int s, len;
	struct sockaddr_un local;
	
	char *name;
	wchar_t *wdir;
	wchar_t *wuname;	
	char *dir =0, *uname=0;

	get_socket_count++;
	wdir = path;
	wuname = user;
	
	if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) 
	{
		wperror(L"socket");
		return -1;
	}
	
	if( wdir )
		dir = wcs2str(wdir );
	else
		dir = strdup("/tmp");
	
	if( wuname )
		uname = wcs2str(wuname );
	else
	{
		struct passwd *pw;
		pw = getpwuid( getuid() );
		uname = strdup( pw->pw_name );
	}
	
	name = malloc( strlen(dir) +
				   strlen(uname) + 
				   strlen(SOCK_FILENAME) + 
				   2 );
	
	strcpy( name, dir );
	strcat( name, "/" );
	strcat( name, SOCK_FILENAME );
	strcat( name, uname );
	
	free( dir );
	free( uname );
	
	debug( 3, L"Connect to socket %s at fd %2", name, s );
	
	local.sun_family = AF_UNIX;
	strcpy(local.sun_path, name );
	free( name );
	len = strlen(local.sun_path) + sizeof(local.sun_family);
	
	if( connect( s, (struct sockaddr *)&local, len) == -1 ) 
	{
		close( s );
		if( fork_ok )
		{
			debug( 2, L"Could not connect to socket %d, starting fishd", s );
			
			if( start_fishd )
			{
				start_fishd();
			}
			
			return get_socket( 0 );
		}
		
		debug( 3, L"Could not connect to socket %d, already tried forking, giving up", s );
		return -1;
	}
	
	if( fcntl( s, F_SETFL, O_NONBLOCK ) != 0 )
	{
		wperror( L"fcntl" );
		close( s );		
		
		return -1;
	}
	
	debug( 3, L"Connected to fd %d", s );
	
	return s;
}

/**
   Callback function used whenever a new fishd message is recieved
*/
static void callback( int type, const wchar_t *name, const wchar_t *val )
{	
	if( type == BARRIER_REPLY )
	{
		debug( 3, L"Got barrier reply" );
		barrier_reply = 1;
	}
	else
	{
		if( external_callback )
			external_callback( type, name, val );		
	}	
}

/**
   Make sure the connection is healthy. If not, close it, and try to
   establish a new connection.
*/
static void check_connection()
{
	if( !init )
		return;
	
	if( env_universal_server.killme )
	{
		debug( 2, L"Lost connection to universal variable server." );
		close( env_universal_server.fd );
		env_universal_server.fd = -1;
		env_universal_server.killme=0;
		sb_clear( &env_universal_server.input );	
		env_universal_read_all();
	}	
}

/**
   Try to establish a new connection to fishd. If successfull, end
   with call to env_universal_barrier(), to make sure everything is in
   sync.
*/
static void reconnect()
{
	if( get_socket_count >= RECONNECT_COUNT )
		return;
	
	debug( 2, L"Get new fishd connection" );
	
	init = 0;
	env_universal_server.fd = get_socket(1);
	init = 1;
	if( env_universal_server.fd >= 0 )
	{
		env_universal_barrier();
	}
}


void env_universal_init( wchar_t * p, 
						 wchar_t *u, 
						 void (*sf)(),
						 void (*cb)( int type, const wchar_t *name, const wchar_t *val ))
{
	debug( 2, L"env_universal_init()" );
	path=p;
	user=u;
	start_fishd=sf;	
	external_callback = cb;
	
	env_universal_server.fd = -1;
	env_universal_server.killme = 0;
	env_universal_server.fd = get_socket(1);
	memset (&env_universal_server.wstate, '\0', sizeof (mbstate_t));
	q_init( &env_universal_server.unsent );
	env_universal_common_init( &callback );
	sb_init( &env_universal_server.input );	
	env_universal_read_all();	
	init = 1;	
	if( env_universal_server.fd >= 0 )
	{
		env_universal_barrier();
	}
	debug( 2, L"end env_universal_init()" );
}

void env_universal_destroy()
{
	/*
	  Go into blocking mode and send all data before exiting
	*/
	if( env_universal_server.fd >= 0 )
	{
		if( fcntl( env_universal_server.fd, F_SETFL, 0 ) != 0 )
		{
			wperror( L"fcntl" );
		}
		try_send_all( &env_universal_server );	
	}
	close( env_universal_server.fd );
	env_universal_server.fd =-1;
	q_destroy( &env_universal_server.unsent );
	sb_destroy( &env_universal_server.input );	
	env_universal_common_destroy();
	init = 0;
}


/**
   Read all available messages from the server.
*/
int env_universal_read_all()
{
	if( !init)
		return 0;

	if( env_universal_server.fd == -1 )
	{
		reconnect();		
		if( env_universal_server.fd == -1 )
			return 0;		
	}
	
	if( env_universal_server.fd != -1 )
	{
		read_message( &env_universal_server );
		check_connection();		
		return 1;
	}
	else
	{
		debug( 2, L"No connection to universal variable server" );
		return 0;
	}		
}

wchar_t *env_universal_get( const wchar_t *name )
{
	if( !init)
		return 0;
	
	if( !name )
		return 0;

	return env_universal_common_get( name );
}

int env_universal_get_export( const wchar_t *name )
{
	return env_universal_common_get_export( name );
}

void env_universal_barrier()
{
	message_t *msg;
	fd_set fds;

	if( !init || ( env_universal_server.fd == -1 ))
		return;
	
	barrier_reply = 0;

	/*
	  Create barrier request
	*/
	msg= create_message( BARRIER, 0, 0);
	msg->count=1;
	q_put( &env_universal_server.unsent, msg );

	/*
	  Wait until barrier request has been sent
	*/
	debug( 3, L"Create barrier" );
	while( 1 )
	{
		try_send_all( &env_universal_server );	
		check_connection();		
		
		if( q_empty( &env_universal_server.unsent ) )
			break;
		
		if( env_universal_server.fd == -1 )
		{
			reconnect();
			return;			
		}
		
		FD_ZERO( &fds );
		FD_SET( env_universal_server.fd, &fds );
		select( env_universal_server.fd+1, 0, &fds, 0, 0 );
	}
	
	/*
	  Wait for barrier reply
	*/
	debug( 3, L"Sent barrier request" );
	while( !barrier_reply )
	{
		if( env_universal_server.fd == -1 )
		{
			reconnect();
			return;			
		}		
		FD_ZERO( &fds );
        FD_SET( env_universal_server.fd, &fds );		
        select( env_universal_server.fd+1, &fds, 0, 0, 0 );
		env_universal_read_all();
	}
	debug( 3, L"End barrier" );
}


void env_universal_set( const wchar_t *name, const wchar_t *value, int export )
{
	message_t *msg;
	
	if( !init )
		return;
	
	debug( 3, L"env_universal_set( %ls, %ls )", name, value );
	
	msg = create_message( export?SET_EXPORT:SET, 
						  name, 
						  value);

	if( !msg )
	{
		debug( 1, L"Could not create universal variable message" );
		return;
	}
	
	msg->count=1;
	q_put( &env_universal_server.unsent, msg );
	env_universal_barrier();
}

void env_universal_remove( const wchar_t *name )
{
	message_t *msg;
	if( !init )
		return;
	
	debug( 2,
		   L"env_universal_remove( %ls )",
		   name );

	msg= create_message( ERASE, name, 0);
	msg->count=1;
	q_put( &env_universal_server.unsent, msg );
	env_universal_barrier();
}

void env_universal_get_names( array_list_t *l,
                              int show_exported,
                              int show_unexported )
{
	env_universal_common_get_names( l, 
									show_exported,
									show_unexported );	
}