/** * 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); }