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-common.h"
  27 #include "sysemu/char.h"
  28
  29 #define BUF_SIZE 32
  30
  31 typedef struct {
  32     CharDriverState *chr;
  33     uint8_t in_buf[32];
  34     int in_buf_used;
  35 } TestdevCharState;
  36
  37 /* Try to interpret a whole incoming packet */
  38 static int testdev_eat_packet(TestdevCharState *testdev)
  39 {
  40     const uint8_t *cur = testdev->in_buf;
  41     int len = testdev->in_buf_used;
  42     uint8_t c;
  43     int arg;
  44
  45 #define EAT(c) do { \
  46     if (!len--) {   \
  47         return 0;   \
  48     }               \
  49     c = *cur++;     \
  50 } while (0)
  51
  52     EAT(c);
  53
  54     while (isspace(c)) {
  55         EAT(c);
  56     }
  57
  58     arg = 0;
  59     while (isdigit(c)) {
  60         arg = arg * 10 + c - '0';
  61         EAT(c);
  62     }
  63
  64     while (isspace(c)) {
  65         EAT(c);
  66     }
  67
  68     switch (c) {
  69     case 'q':
  70         exit((arg << 1) | 1);
  71         break;
  72     default:
  73         break;
  74     }
  75     return cur - testdev->in_buf;
  76 }
  77
  78 /* The other end is writing some data.  Store it and try to interpret */
  79 static int testdev_write(CharDriverState *chr, const uint8_t *buf, int len)
  80 {
  81     TestdevCharState *testdev = chr->opaque;
  82     int tocopy, eaten, orig_len = len;
  83
  84     while (len) {
  85         /* Complete our buffer as much as possible */
  86         tocopy = MIN(len, BUF_SIZE - testdev->in_buf_used);
  87
  88         memcpy(testdev->in_buf + testdev->in_buf_used, buf, tocopy);
  89         testdev->in_buf_used += tocopy;
  90         buf += tocopy;
  91         len -= tocopy;
  92
  93         /* Interpret it as much as possible */
  94         while (testdev->in_buf_used > 0 &&
  95                (eaten = testdev_eat_packet(testdev)) > 0) {
  96             memmove(testdev->in_buf, testdev->in_buf + eaten,
  97                     testdev->in_buf_used - eaten);
  98             testdev->in_buf_used -= eaten;
  99         }
 100     }
 101     return orig_len;
 102 }
 103
 104 static void testdev_close(struct CharDriverState *chr)
 105 {
 106     TestdevCharState *testdev = chr->opaque;
 107
 108     g_free(testdev);
 109 }
 110
 111 static CharDriverState *chr_testdev_init(const char *id,
 112                                          ChardevBackend *backend,
 113                                          ChardevReturn *ret,
 114                                          Error **errp)
 115 {
 116     TestdevCharState *testdev;
 117     CharDriverState *chr;
 118
 119     testdev = g_new0(TestdevCharState, 1);
 120     testdev->chr = chr = g_new0(CharDriverState, 1);
 121
 122     chr->opaque = testdev;
 123     chr->chr_write = testdev_write;
 124     chr->chr_close = testdev_close;
 125
 126     return chr;
 127 }
 128
 129 static void register_types(void)
 130 {
 131     register_char_driver("testdev", CHARDEV_BACKEND_KIND_TESTDEV, NULL,
 132                          chr_testdev_init);
 133 }
 134
 135 type_init(register_types);