Return to command_unix.c CVS log

Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / mtr / packet

Annotation of embedaddon/mtr/packet/command_unix.c, revision 1.1

1.1     ! misho       1: /*
        !             2:     mtr  --  a network diagnostic tool
        !             3:     Copyright (C) 2016  Matt Kimball
        !             4: 
        !             5:     This program is free software; you can redistribute it and/or modify
        !             6:     it under the terms of the GNU General Public License version 2 as
        !             7:     published by the Free Software Foundation.
        !             8: 
        !             9:     This program is distributed in the hope that it will be useful,
        !            10:     but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            11:     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            12:     GNU General Public License for more details.
        !            13: 
        !            14:     You should have received a copy of the GNU General Public License
        !            15:     along with this program; if not, write to the Free Software
        !            16:     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
        !            17: */
        !            18: 
        !            19: #include "command.h"
        !            20: 
        !            21: #include <errno.h>
        !            22: #include <fcntl.h>
        !            23: #include <string.h>
        !            24: #include <stdio.h>
        !            25: #include <stdlib.h>
        !            26: #include <unistd.h>
        !            27: 
        !            28: /*
        !            29:     Initialize the command buffer and put the command stream in
        !            30:     non-blocking mode.
        !            31: */
        !            32: void init_command_buffer(
        !            33:     struct command_buffer_t *command_buffer,
        !            34:     int command_stream)
        !            35: {
        !            36:     int flags;
        !            37: 
        !            38:     memset(command_buffer, 0, sizeof(struct command_buffer_t));
        !            39:     command_buffer->command_stream = command_stream;
        !            40: 
        !            41:     /*  Get the current command stream flags  */
        !            42:     flags = fcntl(command_stream, F_GETFL, 0);
        !            43:     if (flags == -1) {
        !            44:         perror("Unexpected command stream error");
        !            45:         exit(EXIT_FAILURE);
        !            46:     }
        !            47: 
        !            48:     /*  Set the O_NONBLOCK bit  */
        !            49:     if (fcntl(command_stream, F_SETFL, flags | O_NONBLOCK)) {
        !            50:         perror("Unexpected command stream error");
        !            51:         exit(EXIT_FAILURE);
        !            52:     }
        !            53: }
        !            54: 
        !            55: /*  Read currently available data from the command stream  */
        !            56: int read_commands(
        !            57:     struct command_buffer_t *buffer)
        !            58: {
        !            59:     int space_remaining =
        !            60:         COMMAND_BUFFER_SIZE - buffer->incoming_read_position - 1;
        !            61:     char *read_position =
        !            62:         &buffer->incoming_buffer[buffer->incoming_read_position];
        !            63:     int read_count;
        !            64:     int command_stream = buffer->command_stream;
        !            65: 
        !            66:     read_count = read(command_stream, read_position, space_remaining);
        !            67: 
        !            68:     /*  If the command stream has been closed, read will return zero.  */
        !            69:     if (read_count == 0) {
        !            70:         errno = EPIPE;
        !            71:         return -1;
        !            72:     }
        !            73: 
        !            74:     if (read_count > 0) {
        !            75:         /*  Account for the newly read data  */
        !            76:         buffer->incoming_read_position += read_count;
        !            77:     }
        !            78: 
        !            79:     if (read_count < 0) {
        !            80:         /*  EAGAIN simply means there is no available data to read  */
        !            81:         /*  EINTR indicates we received a signal during read  */
        !            82:         if (errno != EINTR && errno != EAGAIN) {
        !            83:             perror("Unexpected command buffer read error");
        !            84:             exit(EXIT_FAILURE);
        !            85:         }
        !            86:     }
        !            87: 
        !            88:     return 0;
        !            89: }