/**
* coopgammad -- Cooperative gamma server
* Copyright (C) 2016 Mattias Andrée (maandree@kth.se)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "communication.h"
#include "state.h"
#include "servers/coopgamma.h"
#include <sys/socket.h>
#include <errno.h>
#include <string.h>
/**
* Send a message
*
* @param conn The index of the connection
* @param buf The data to send
* @param n The size of `buf`
* @return Zero on success, -1 on error, 1 if disconncted
* EINTR, EAGAIN, EWOULDBLOCK, and ECONNRESET count
* as success (ECONNRESET cause 1 to be returned),
* and are handled appropriately.
*/
int send_message(size_t conn, char* restrict buf, size_t n)
{
struct ring* restrict ring = outbound + conn;
int fd = connections[conn];
int saved_errno;
size_t ptr = 0;
ssize_t sent;
size_t chunksize = n;
size_t sendsize;
size_t old_n;
char* old_buf;
while ((old_buf = ring_peek(ring, &old_n)))
{
size_t old_ptr = 0;
while (old_ptr < n)
{
sendsize = old_n - old_ptr < chunksize ? old_n - old_ptr : chunksize;
sent = send(fd, old_buf + old_ptr, sendsize, MSG_NOSIGNAL);
if (sent < 0)
{
if (errno == EPIPE)
errno = ECONNRESET;
if (errno != EMSGSIZE)
goto fail;
chunksize >>= 1;
if (chunksize == 0)
goto fail;
continue;
}
old_ptr += (size_t)sent;
ring_pop(ring, (size_t)sent);
}
}
while (ptr < n)
{
sendsize = n - ptr < chunksize ? n - ptr : chunksize;
sent = send(fd, buf + ptr, sendsize, MSG_NOSIGNAL);
if (sent < 0)
{
if (errno == EPIPE)
errno = ECONNRESET;
if (errno != EMSGSIZE)
goto fail;
chunksize >>= 1;
if (chunksize == 0)
goto fail;
continue;
}
ptr += (size_t)sent;
}
free(buf);
return 0;
fail:
switch (errno)
{
case EINTR:
case EAGAIN:
#if EAGAIN != EWOULDBLOCK
case EWOULDBLOCK:
#endif
if (ring_push(ring, buf + ptr, n - ptr) < 0)
goto proper_fail;
free(buf);
return 0;
case ECONNRESET:
free(buf);
if (connection_closed(fd) < 0)
return -1;
return 1;
default:
break;
}
proper_fail:
saved_errno = errno;
free(buf);
errno = saved_errno;
return -1;
}
/**
* Send a custom error without an error number
*
* @param conn The index of the connection
* @param message_id The ID of the message to which this message is a response
* @param desc The error description to send
* @return 1: Client disconnected
* 0: Success (possibily delayed)
* -1: An error occurred
*/
int (send_error)(size_t conn, const char* restrict message_id, const char* restrict desc)
{
char* restrict buf;
size_t n;
MAKE_MESSAGE(&buf, &n, 0,
"Command: error\n"
"In response to: %s\n"
"Error: custom\n"
"Length: %zu\n"
"\n"
"%s\n",
message_id, strlen(desc) + 1, desc);
return send_message(conn, buf, n);
}
/**
* Send a standard error
*
* @param conn The index of the connection
* @param message_id The ID of the message to which this message is a response
* @param number The value of `errno`, 0 to indicate success
* @return 1: Client disconnected
* 0: Success (possibily delayed)
* -1: An error occurred
*/
int (send_errno)(size_t conn, const char* restrict message_id, int number)
{
char* restrict buf;
size_t n;
MAKE_MESSAGE(&buf, &n, 0,
"Command: error\n"
"In response to: %s\n"
"Error: %i\n"
"\n",
message_id, number);
return send_message(conn, buf, n);
}
