qdevices/qdevice-heuristics-io.c

   1 /*
   2  * Copyright (c) 2015-2017 Red Hat, Inc.
   3  *
   4  * All rights reserved.
   5  *
   6  * Author: Jan Friesse (jfriesse@redhat.com)
   7  *
   8  * This software licensed under BSD license, the text of which follows:
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions are met:
  12  *
  13  * - Redistributions of source code must retain the above copyright notice,
  14  *   this list of conditions and the following disclaimer.
  15  * - Redistributions in binary form must reproduce the above copyright notice,
  16  *   this list of conditions and the following disclaimer in the documentation
  17  *   and/or other materials provided with the distribution.
  18  * - Neither the name of the Red Hat, Inc. nor the names of its
  19  *   contributors may be used to endorse or promote products derived from this
  20  *   software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  23  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  26  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  32  * THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #include <limits.h>
  36 #include <errno.h>
  37 #include <signal.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include "qdevice-heuristics-io.h"
  43
  44 #define QDEVICE_HEURISTICS_IO_BUFFER_SIZE       256
  45
  46 ssize_t
  47 qdevice_heuristics_io_blocking_write(int fd, const void *buf, size_t count)
  48 {
  49         ssize_t bytes_written;
  50         ssize_t tmp_bytes_written;
  51
  52         bytes_written = 0;
  53
  54         do {
  55                 tmp_bytes_written = write(fd, (const char *)buf + bytes_written,
  56                     (count - bytes_written > SSIZE_MAX) ? SSIZE_MAX : count - bytes_written);
  57                 if (tmp_bytes_written == -1) {
  58                         if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) {
  59                                 return (-1);
  60                         }
  61                 } else {
  62                         bytes_written += tmp_bytes_written;
  63                 }
  64         } while ((size_t)bytes_written != count);
  65
  66         return (bytes_written);
  67 }
  68
  69 /*
  70  *  1 Full line readed (at least one \n found)
  71  *  0 Partial read (no error)
  72  * -1 End of connection
  73  * -2 Buffer too long
  74  * -3 Unhandled error
  75  */
  76 int
  77 qdevice_heuristics_io_read(int fd, struct dynar *dest)
  78 {
  79         char buf[QDEVICE_HEURISTICS_IO_BUFFER_SIZE];
  80         ssize_t readed;
  81         int res;
  82         size_t zi;
  83
  84         res = 0;
  85         readed = read(fd, buf, sizeof(buf));
  86         if (readed > 0) {
  87                 if (dynar_cat(dest, buf, readed) == -1) {
  88                         res = -2;
  89                         goto exit_err;
  90                 }
  91
  92                 for (zi = 0; zi < (size_t)readed; zi++) {
  93                         if (buf[zi] == '\n') {
  94                                 res = 1;
  95                         }
  96                 }
  97         }
  98
  99         if (readed == 0) {
 100                 res = -1;
 101         }
 102
 103         if (readed < 0 && errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR) {
 104                 res = -3;
 105         }
 106
 107 exit_err:
 108         return (res);
 109 }
 110
 111 /*
 112  * 1 All data succesfully sent
 113  *  0 Partial send (no error)
 114  * -1 send returned 0,
 115  * -2 Unhandled error
 116  */
 117 int
 118 qdevice_heuristics_io_write(int fd, const struct dynar *msg, size_t *already_sent_bytes)
 119 {
 120         ssize_t sent;
 121         size_t to_send;
 122         int res;
 123
 124         res = 0;
 125
 126         to_send = dynar_size(msg) - *already_sent_bytes;
 127         if (to_send > QDEVICE_HEURISTICS_IO_BUFFER_SIZE) {
 128                 to_send = QDEVICE_HEURISTICS_IO_BUFFER_SIZE;
 129         }
 130
 131         sent = write(fd, dynar_data(msg) + *already_sent_bytes,
 132             to_send);
 133
 134         if (sent > 0) {
 135                 *already_sent_bytes += sent;
 136
 137                 if (*already_sent_bytes == dynar_size(msg)) {
 138                         return (1);
 139                 }
 140         }
 141
 142         if (sent == 0) {
 143                 res = -1;
 144         }
 145
 146         if (sent < 0 && errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR) {
 147                 res = -2;
 148         }
 149
 150         return (res);
 151 }