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     CharDriverState *chr;
  34     uint8_t in_buf[32];
  35     int in_buf_used;
  36 } TestdevCharState;
  37
  38 /* Try to interpret a whole incoming packet */
  39 static int testdev_eat_packet(TestdevCharState *testdev)
  40 {
  41     const uint8_t *cur = testdev->in_buf;
  42     int len = testdev->in_buf_used;
  43     uint8_t c;
  44     int arg;
  45
  46 #define EAT(c) do { \
  47     if (!len--) {   \
  48         return 0;   \
  49     }               \
  50     c = *cur++;     \
  51 } while (0)
  52
  53     EAT(c);
  54
  55     while (isspace(c)) {
  56         EAT(c);
  57     }
  58
  59     arg = 0;
  60     while (isdigit(c)) {
  61         arg = arg * 10 + c - '0';
  62         EAT(c);
  63     }
  64
  65     while (isspace(c)) {
  66         EAT(c);
  67     }
  68
  69     switch (c) {
  70     case 'q':
  71         exit((arg << 1) | 1);
  72         break;
  73     default:
  74         break;
  75     }
  76     return cur - testdev->in_buf;
  77 }
  78
  79 /* The other end is writing some data.  Store it and try to interpret */
  80 static int testdev_write(CharDriverState *chr, const uint8_t *buf, int len)
  81 {
  82     TestdevCharState *testdev = chr->opaque;
  83     int tocopy, eaten, orig_len = len;
  84
  85     while (len) {
  86         /* Complete our buffer as much as possible */
  87         tocopy = MIN(len, BUF_SIZE - testdev->in_buf_used);
  88
  89         memcpy(testdev->in_buf + testdev->in_buf_used, buf, tocopy);
  90         testdev->in_buf_used += tocopy;
  91         buf += tocopy;
  92         len -= tocopy;
  93
  94         /* Interpret it as much as possible */
  95         while (testdev->in_buf_used > 0 &&
  96                (eaten = testdev_eat_packet(testdev)) > 0) {
  97             memmove(testdev->in_buf, testdev->in_buf + eaten,
  98                     testdev->in_buf_used - eaten);
  99             testdev->in_buf_used -= eaten;
 100         }
 101     }
 102     return orig_len;
 103 }
 104
 105 static void testdev_free(struct CharDriverState *chr)
 106 {
 107     TestdevCharState *testdev = chr->opaque;
 108
 109     g_free(testdev);
 110 }
 111
 112 static CharDriverState *chr_testdev_init(const char *id,
 113                                          ChardevBackend *backend,
 114                                          ChardevReturn *ret,
 115                                          bool *be_opened,
 116                                          Error **errp)
 117 {
 118     TestdevCharState *testdev;
 119     CharDriverState *chr;
 120
 121     testdev = g_new0(TestdevCharState, 1);
 122     testdev->chr = chr = g_new0(CharDriverState, 1);
 123
 124     chr->opaque = testdev;
 125     chr->chr_write = testdev_write;
 126     chr->chr_free = testdev_free;
 127
 128     return chr;
 129 }
 130
 131 static void register_types(void)
 132 {
 133     register_char_driver("testdev", CHARDEV_BACKEND_KIND_TESTDEV, NULL,
 134                          chr_testdev_init);
 135 }
 136
 137 type_init(register_types);