Sweden-Number/server/socket.c

335 lines
9.4 KiB
C

/*
* Server-side socket communication functions
*
* Copyright (C) 1998 Alexandre Julliard
*/
#include <assert.h>
#include <errno.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 "server.h"
#include "server/object.h"
/* Some versions of glibc don't define this */
#ifndef SCM_RIGHTS
#define SCM_RIGHTS 1
#endif
/* client state */
enum state
{
RUNNING, /* running normally */
SENDING, /* sending us a request */
WAITING, /* waiting for us to reply */
READING /* reading our reply */
};
/* client structure */
struct client
{
enum state state; /* client state */
unsigned int seq; /* current sequence number */
struct header head; /* current msg header */
char *data; /* current msg data */
int count; /* bytes sent/received so far */
int pass_fd; /* fd to pass to and from the client */
struct thread *self; /* client thread (opaque pointer) */
};
/* exit code passed to remove_client */
#define OUT_OF_MEMORY -1
#define BROKEN_PIPE -2
#define PROTOCOL_ERROR -3
/* signal a client protocol error */
static void protocol_error( int client_fd, const char *err, ... )
{
va_list args;
va_start( args, err );
fprintf( stderr, "Protocol error:%d: ", client_fd );
vfprintf( stderr, err, args );
va_end( args );
}
/* send a message to a client that is ready to receive something */
static void do_write( struct client *client, int client_fd )
{
struct iovec vec[2];
#ifndef HAVE_MSGHDR_ACCRIGHTS
struct cmsg_fd cmsg = { sizeof(cmsg), SOL_SOCKET, SCM_RIGHTS,
client->pass_fd };
#endif
struct msghdr msghdr = { NULL, 0, vec, 2, };
int ret;
/* make sure we have something to send */
assert( client->count < client->head.len );
/* make sure the client is listening */
assert( client->state == READING );
if (client->count < sizeof(client->head))
{
vec[0].iov_base = (char *)&client->head + client->count;
vec[0].iov_len = sizeof(client->head) - client->count;
vec[1].iov_base = client->data;
vec[1].iov_len = client->head.len - sizeof(client->head);
}
else
{
vec[0].iov_base = client->data + client->count - sizeof(client->head);
vec[0].iov_len = client->head.len - client->count;
msghdr.msg_iovlen = 1;
}
if (client->pass_fd != -1) /* we have an fd to send */
{
#ifdef HAVE_MSGHDR_ACCRIGHTS
msghdr.msg_accrights = (void *)&client->pass_fd;
msghdr.msg_accrightslen = sizeof(client->pass_fd);
#else
msghdr.msg_control = &cmsg;
msghdr.msg_controllen = sizeof(cmsg);
#endif
}
ret = sendmsg( client_fd, &msghdr, 0 );
if (ret == -1)
{
if (errno != EPIPE) perror("sendmsg");
remove_client( client_fd, BROKEN_PIPE );
return;
}
if (client->pass_fd != -1) /* We sent the fd, now we can close it */
{
close( client->pass_fd );
client->pass_fd = -1;
}
if ((client->count += ret) < client->head.len) return;
/* we have finished with this message */
if (client->data) free( client->data );
client->data = NULL;
client->count = 0;
client->state = RUNNING;
client->seq++;
set_select_events( client_fd, READ_EVENT );
}
/* read a message from a client that has something to say */
static void do_read( struct client *client, int client_fd )
{
struct iovec vec;
int pass_fd = -1;
#ifdef HAVE_MSGHDR_ACCRIGHTS
struct msghdr msghdr = { NULL, 0, &vec, 1, (void*)&pass_fd, sizeof(int) };
#else
struct cmsg_fd cmsg = { sizeof(cmsg), SOL_SOCKET, SCM_RIGHTS, -1 };
struct msghdr msghdr = { NULL, 0, &vec, 1, &cmsg, sizeof(cmsg), 0 };
#endif
int ret;
if (client->count < sizeof(client->head))
{
vec.iov_base = (char *)&client->head + client->count;
vec.iov_len = sizeof(client->head) - client->count;
}
else
{
if (!client->data &&
!(client->data = malloc(client->head.len-sizeof(client->head))))
{
remove_client( client_fd, OUT_OF_MEMORY );
return;
}
vec.iov_base = client->data + client->count - sizeof(client->head);
vec.iov_len = client->head.len - client->count;
}
ret = recvmsg( client_fd, &msghdr, 0 );
if (ret == -1)
{
perror("recvmsg");
remove_client( client_fd, BROKEN_PIPE );
return;
}
#ifndef HAVE_MSGHDR_ACCRIGHTS
pass_fd = cmsg.fd;
#endif
if (pass_fd != -1)
{
/* can only receive one fd per message */
if (client->pass_fd != -1) close( client->pass_fd );
client->pass_fd = pass_fd;
}
else if (!ret) /* closed pipe */
{
remove_client( client_fd, BROKEN_PIPE );
return;
}
if (client->state == RUNNING) client->state = SENDING;
assert( client->state == SENDING );
client->count += ret;
/* received the complete header yet? */
if (client->count < sizeof(client->head)) return;
/* sanity checks */
if (client->head.seq != client->seq)
{
protocol_error( client_fd, "bad sequence %08x instead of %08x\n",
client->head.seq, client->seq );
remove_client( client_fd, PROTOCOL_ERROR );
return;
}
if ((client->head.len < sizeof(client->head)) ||
(client->head.len > MAX_MSG_LENGTH + sizeof(client->head)))
{
protocol_error( client_fd, "bad header length %08x\n",
client->head.len );
remove_client( client_fd, PROTOCOL_ERROR );
return;
}
/* received the whole message? */
if (client->count == client->head.len)
{
/* done reading the data, call the callback function */
int len = client->head.len - sizeof(client->head);
char *data = client->data;
int passed_fd = client->pass_fd;
enum request type = client->head.type;
/* clear the info now, as the client may be deleted by the callback */
client->head.len = 0;
client->head.type = 0;
client->count = 0;
client->data = NULL;
client->pass_fd = -1;
client->state = WAITING;
client->seq++;
call_req_handler( client->self, type, data, len, passed_fd );
if (passed_fd != -1) close( passed_fd );
if (data) free( data );
}
}
/* handle a client timeout */
static void client_timeout( int client_fd, void *private )
{
struct client *client = (struct client *)private;
set_select_timeout( client_fd, 0 ); /* Remove the timeout */
call_timeout_handler( client->self );
}
/* handle a client event */
static void client_event( int client_fd, int event, void *private )
{
struct client *client = (struct client *)private;
if (event & WRITE_EVENT)
do_write( client, client_fd );
if (event & READ_EVENT)
do_read( client, client_fd );
}
static const struct select_ops client_ops =
{
client_event,
client_timeout
};
/*******************************************************************/
/* server-side exported functions */
/* add a client */
int add_client( int client_fd, struct thread *self )
{
struct client *client = malloc( sizeof(*client) );
if (!client) return -1;
client->state = RUNNING;
client->seq = 0;
client->head.len = 0;
client->head.type = 0;
client->count = 0;
client->data = NULL;
client->self = self;
client->pass_fd = -1;
if (add_select_user( client_fd, READ_EVENT, &client_ops, client ) == -1)
{
free( client );
return -1;
}
return client_fd;
}
/* remove a client */
void remove_client( int client_fd, int exit_code )
{
struct client *client = (struct client *)get_select_private_data( &client_ops, client_fd );
assert( client );
call_kill_handler( client->self, exit_code );
remove_select_user( client_fd );
close( client_fd );
/* Purge messages */
if (client->data) free( client->data );
if (client->pass_fd != -1) close( client->pass_fd );
free( client );
}
/* send a reply to a client */
int send_reply_v( int client_fd, int type, int pass_fd,
struct iovec *vec, int veclen )
{
int i;
unsigned int len;
char *p;
struct client *client = (struct client *)get_select_private_data( &client_ops, client_fd );
assert( client );
assert( client->state == WAITING );
assert( !client->data );
if (debug_level) trace_reply( client->self, type, pass_fd, vec, veclen );
for (i = len = 0; i < veclen; i++) len += vec[i].iov_len;
assert( len < MAX_MSG_LENGTH );
if (len && !(client->data = malloc( len ))) return -1;
client->count = 0;
client->head.len = len + sizeof(client->head);
client->head.type = type;
client->head.seq = client->seq;
client->pass_fd = pass_fd;
for (i = 0, p = client->data; i < veclen; i++)
{
memcpy( p, vec[i].iov_base, vec[i].iov_len );
p += vec[i].iov_len;
}
client->state = READING;
set_select_events( client_fd, WRITE_EVENT );
return 0;
}