backends/testdev.c

   1 /*
   2  * QEMU Char Device for testsuite control
   3  *
   4  * Copyright (c) 2014 Red Hat, Inc.
   5  *
   6  * Author: Paolo Bonzini <pbonzini@redhat.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24  * THE SOFTWARE.
  25  */
  26 #include "qemu/osdep.h"
  27 #include "qemu-common.h"
  28 #include "sysemu/char.h"
  29
  30 #define BUF_SIZE 32
  31
  32 typedef struct {
  33     Chardev parent;
  34
  35     uint8_t in_buf[32];
  36     int in_buf_used;
  37 } TestdevChardev;
  38
  39 #define TYPE_CHARDEV_TESTDEV "chardev-testdev"
  40 #define TESTDEV_CHARDEV(obj)                                    \
  41     OBJECT_CHECK(TestdevChardev, (obj), TYPE_CHARDEV_TESTDEV)
  42
  43 /* Try to interpret a whole incoming packet */
  44 static int testdev_eat_packet(TestdevChardev *testdev)
  45 {
  46     const uint8_t *cur = testdev->in_buf;
  47     int len = testdev->in_buf_used;
  48     uint8_t c;
  49     int arg;
  50
  51 #define EAT(c) do { \
  52     if (!len--) {   \
  53         return 0;   \
  54     }               \
  55     c = *cur++;     \
  56 } while (0)
  57
  58     EAT(c);
  59
  60     while (isspace(c)) {
  61         EAT(c);
  62     }
  63
  64     arg = 0;
  65     while (isdigit(c)) {
  66         arg = arg * 10 + c - '0';
  67         EAT(c);
  68     }
  69
  70     while (isspace(c)) {
  71         EAT(c);
  72     }
  73
  74     switch (c) {
  75     case 'q':
  76         exit((arg << 1) | 1);
  77         break;
  78     default:
  79         break;
  80     }
  81     return cur - testdev->in_buf;
  82 }
  83
  84 /* The other end is writing some data.  Store it and try to interpret */
  85 static int testdev_chr_write(Chardev *chr, const uint8_t *buf, int len)
  86 {
  87     TestdevChardev *testdev = TESTDEV_CHARDEV(chr);
  88     int tocopy, eaten, orig_len = len;
  89
  90     while (len) {
  91         /* Complete our buffer as much as possible */
  92         tocopy = MIN(len, BUF_SIZE - testdev->in_buf_used);
  93
  94         memcpy(testdev->in_buf + testdev->in_buf_used, buf, tocopy);
  95         testdev->in_buf_used += tocopy;
  96         buf += tocopy;
  97         len -= tocopy;
  98
  99         /* Interpret it as much as possible */
 100         while (testdev->in_buf_used > 0 &&
 101                (eaten = testdev_eat_packet(testdev)) > 0) {
 102             memmove(testdev->in_buf, testdev->in_buf + eaten,
 103                     testdev->in_buf_used - eaten);
 104             testdev->in_buf_used -= eaten;
 105         }
 106     }
 107     return orig_len;
 108 }
 109
 110 static void char_testdev_class_init(ObjectClass *oc, void *data)
 111 {
 112     ChardevClass *cc = CHARDEV_CLASS(oc);
 113
 114     cc->chr_write = testdev_chr_write;
 115 }
 116
 117 static const TypeInfo char_testdev_type_info = {
 118     .name = TYPE_CHARDEV_TESTDEV,
 119     .parent = TYPE_CHARDEV,
 120     .instance_size = sizeof(TestdevChardev),
 121     .class_init = char_testdev_class_init,
 122 };
 123
 124 static void register_types(void)
 125 {
 126     type_register_static(&char_testdev_type_info);
 127 }
 128
 129 type_init(register_types);