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 /* Try to interpret a whole incoming packet */
  40 static int testdev_eat_packet(TestdevChardev *testdev)
  41 {
  42     const uint8_t *cur = testdev->in_buf;
  43     int len = testdev->in_buf_used;
  44     uint8_t c;
  45     int arg;
  46
  47 #define EAT(c) do { \
  48     if (!len--) {   \
  49         return 0;   \
  50     }               \
  51     c = *cur++;     \
  52 } while (0)
  53
  54     EAT(c);
  55
  56     while (isspace(c)) {
  57         EAT(c);
  58     }
  59
  60     arg = 0;
  61     while (isdigit(c)) {
  62         arg = arg * 10 + c - '0';
  63         EAT(c);
  64     }
  65
  66     while (isspace(c)) {
  67         EAT(c);
  68     }
  69
  70     switch (c) {
  71     case 'q':
  72         exit((arg << 1) | 1);
  73         break;
  74     default:
  75         break;
  76     }
  77     return cur - testdev->in_buf;
  78 }
  79
  80 /* The other end is writing some data.  Store it and try to interpret */
  81 static int testdev_write(Chardev *chr, const uint8_t *buf, int len)
  82 {
  83     TestdevChardev *testdev = (TestdevChardev *)chr;
  84     int tocopy, eaten, orig_len = len;
  85
  86     while (len) {
  87         /* Complete our buffer as much as possible */
  88         tocopy = MIN(len, BUF_SIZE - testdev->in_buf_used);
  89
  90         memcpy(testdev->in_buf + testdev->in_buf_used, buf, tocopy);
  91         testdev->in_buf_used += tocopy;
  92         buf += tocopy;
  93         len -= tocopy;
  94
  95         /* Interpret it as much as possible */
  96         while (testdev->in_buf_used > 0 &&
  97                (eaten = testdev_eat_packet(testdev)) > 0) {
  98             memmove(testdev->in_buf, testdev->in_buf + eaten,
  99                     testdev->in_buf_used - eaten);
 100             testdev->in_buf_used -= eaten;
 101         }
 102     }
 103     return orig_len;
 104 }
 105
 106 static Chardev *chr_testdev_init(const CharDriver *driver,
 107                                  const char *id,
 108                                  ChardevBackend *backend,
 109                                  ChardevReturn *ret,
 110                                  bool *be_opened,
 111                                  Error **errp)
 112 {
 113     TestdevChardev *testdev = g_new0(TestdevChardev, 1);;
 114     Chardev *chr = (Chardev *)testdev;
 115
 116     chr->driver = driver;
 117
 118     return chr;
 119 }
 120
 121 static void register_types(void)
 122 {
 123     static const CharDriver driver = {
 124         .instance_size = sizeof(TestdevChardev),
 125         .kind = CHARDEV_BACKEND_KIND_TESTDEV,
 126         .create = chr_testdev_init,
 127         .chr_write = testdev_write,
 128     };
 129     register_char_driver(&driver);
 130 }
 131
 132 type_init(register_types);