Sweden-Number/server/socket.c

208 lines
5.6 KiB
C

/*
* Server-side socket communication functions
*
* Copyright (C) 1998 Alexandre Julliard
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <unistd.h>
#include "config.h"
#include "object.h"
#include "request.h"
/* Some versions of glibc don't define this */
#ifndef SCM_RIGHTS
#define SCM_RIGHTS 1
#endif
/* client structure */
struct client
{
struct select_user select; /* select user */
unsigned int res; /* current result to send */
int pass_fd; /* fd to pass to and from the client */
struct thread *self; /* client thread (opaque pointer) */
struct timeout_user *timeout; /* current timeout (opaque pointer) */
};
/* socket communication static structures */
static struct iovec myiovec;
static struct msghdr msghdr = { NULL, 0, &myiovec, 1, };
#ifndef HAVE_MSGHDR_ACCRIGHTS
struct cmsg_fd
{
int len; /* sizeof structure */
int level; /* SOL_SOCKET */
int type; /* SCM_RIGHTS */
int fd; /* fd to pass */
};
static struct cmsg_fd cmsg = { sizeof(cmsg), SOL_SOCKET, SCM_RIGHTS, -1 };
#endif /* HAVE_MSGHDR_ACCRIGHTS */
/* send a message to a client that is ready to receive something */
static int do_write( struct client *client )
{
int ret;
if (client->pass_fd == -1)
{
ret = write( client->select.fd, &client->res, sizeof(client->res) );
if (ret == sizeof(client->res)) goto ok;
}
else /* we have an fd to send */
{
#ifdef HAVE_MSGHDR_ACCRIGHTS
msghdr.msg_accrightslen = sizeof(int);
msghdr.msg_accrights = (void *)&client->pass_fd;
#else /* HAVE_MSGHDR_ACCRIGHTS */
msghdr.msg_control = &cmsg;
msghdr.msg_controllen = sizeof(cmsg);
cmsg.fd = client->pass_fd;
#endif /* HAVE_MSGHDR_ACCRIGHTS */
myiovec.iov_base = (void *)&client->res;
myiovec.iov_len = sizeof(client->res);
ret = sendmsg( client->select.fd, &msghdr, 0 );
close( client->pass_fd );
client->pass_fd = -1;
if (ret == sizeof(client->res)) goto ok;
}
if (ret == -1)
{
if (errno == EWOULDBLOCK) return 0; /* not a fatal error */
if (errno != EPIPE) perror("sendmsg");
}
else fprintf( stderr, "Partial message sent %d/%d\n", ret, sizeof(client->res) );
remove_client( client, BROKEN_PIPE );
return 0;
ok:
set_select_events( &client->select, READ_EVENT );
return 1;
}
/* read a message from a client that has something to say */
static void do_read( struct client *client )
{
int ret;
enum request req;
#ifdef HAVE_MSGHDR_ACCRIGHTS
msghdr.msg_accrightslen = sizeof(int);
msghdr.msg_accrights = (void *)&client->pass_fd;
#else /* HAVE_MSGHDR_ACCRIGHTS */
msghdr.msg_control = &cmsg;
msghdr.msg_controllen = sizeof(cmsg);
cmsg.fd = -1;
#endif /* HAVE_MSGHDR_ACCRIGHTS */
assert( client->pass_fd == -1 );
myiovec.iov_base = (void *)&req;
myiovec.iov_len = sizeof(req);
ret = recvmsg( client->select.fd, &msghdr, 0 );
#ifndef HAVE_MSGHDR_ACCRIGHTS
client->pass_fd = cmsg.fd;
#endif
if (ret == sizeof(req))
{
int pass_fd = client->pass_fd;
client->pass_fd = -1;
call_req_handler( client->self, req, pass_fd );
if (pass_fd != -1) close( pass_fd );
return;
}
if (ret == -1)
{
perror("recvmsg");
remove_client( client, BROKEN_PIPE );
return;
}
if (!ret) /* closed pipe */
{
remove_client( client, BROKEN_PIPE );
return;
}
fatal_protocol_error( client->self, "partial message received %d/%d\n", ret, sizeof(req) );
}
/* handle a client event */
static void client_event( int event, void *private )
{
struct client *client = (struct client *)private;
if (event & WRITE_EVENT) do_write( client );
if (event & READ_EVENT) do_read( client );
}
/*******************************************************************/
/* server-side exported functions */
/* add a client */
struct client *add_client( int fd, struct thread *self )
{
int flags;
struct client *client = mem_alloc( sizeof(*client) );
if (!client) return NULL;
flags = fcntl( fd, F_GETFL, 0 );
fcntl( fd, F_SETFL, flags | O_NONBLOCK );
client->select.fd = fd;
client->select.func = client_event;
client->select.private = client;
client->self = self;
client->timeout = NULL;
client->pass_fd = -1;
register_select_user( &client->select );
set_select_events( &client->select, READ_EVENT );
return client;
}
/* remove a client */
void remove_client( struct client *client, int exit_code )
{
assert( client );
call_kill_handler( client->self, exit_code );
if (client->timeout) remove_timeout_user( client->timeout );
unregister_select_user( &client->select );
close( client->select.fd );
/* Purge messages */
if (client->pass_fd != -1) close( client->pass_fd );
free( client );
}
/* set the fd to pass to the client */
void client_pass_fd( struct client *client, int pass_fd )
{
assert( client->pass_fd == -1 );
client->pass_fd = pass_fd;
}
/* send a reply to a client */
void client_reply( struct client *client, unsigned int res )
{
if (debug_level) trace_reply( client->self, res, client->pass_fd );
client->res = res;
if (!do_write( client )) set_select_events( &client->select, WRITE_EVENT );
}