spice-qemu-char: Fix flow control in client -> guest direction
[sdk/emulator/qemu.git] / spice-qemu-char.c
1 #include "config-host.h"
2 #include "trace.h"
3 #include "ui/qemu-spice.h"
4 #include <spice.h>
5 #include <spice-experimental.h>
6
7 #include "osdep.h"
8
9 #define dprintf(_scd, _level, _fmt, ...)                                \
10     do {                                                                \
11         static unsigned __dprintf_counter = 0;                          \
12         if (_scd->debug >= _level) {                                    \
13             fprintf(stderr, "scd: %3d: " _fmt, ++__dprintf_counter, ## __VA_ARGS__);\
14         }                                                               \
15     } while (0)
16
17 #define VMC_MAX_HOST_WRITE    2048
18
19 typedef struct SpiceCharDriver {
20     CharDriverState*      chr;
21     SpiceCharDeviceInstance     sin;
22     char                  *subtype;
23     bool                  active;
24     uint8_t               *buffer;
25     uint8_t               *datapos;
26     ssize_t               bufsize, datalen;
27     uint32_t              debug;
28 } SpiceCharDriver;
29
30 static int vmc_write(SpiceCharDeviceInstance *sin, const uint8_t *buf, int len)
31 {
32     SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);
33     ssize_t out = 0;
34     ssize_t last_out;
35     uint8_t* p = (uint8_t*)buf;
36
37     while (len > 0) {
38         last_out = MIN(len, VMC_MAX_HOST_WRITE);
39         if (qemu_chr_can_read(scd->chr) < last_out) {
40             break;
41         }
42         qemu_chr_read(scd->chr, p, last_out);
43         out += last_out;
44         len -= last_out;
45         p += last_out;
46     }
47
48     dprintf(scd, 3, "%s: %lu/%zd\n", __func__, out, len + out);
49     trace_spice_vmc_write(out, len + out);
50     return out;
51 }
52
53 static int vmc_read(SpiceCharDeviceInstance *sin, uint8_t *buf, int len)
54 {
55     SpiceCharDriver *scd = container_of(sin, SpiceCharDriver, sin);
56     int bytes = MIN(len, scd->datalen);
57
58     dprintf(scd, 2, "%s: %p %d/%d/%zd\n", __func__, scd->datapos, len, bytes, scd->datalen);
59     if (bytes > 0) {
60         memcpy(buf, scd->datapos, bytes);
61         scd->datapos += bytes;
62         scd->datalen -= bytes;
63         assert(scd->datalen >= 0);
64         if (scd->datalen == 0) {
65             scd->datapos = 0;
66         }
67     }
68     trace_spice_vmc_read(bytes, len);
69     return bytes;
70 }
71
72 static SpiceCharDeviceInterface vmc_interface = {
73     .base.type          = SPICE_INTERFACE_CHAR_DEVICE,
74     .base.description   = "spice virtual channel char device",
75     .base.major_version = SPICE_INTERFACE_CHAR_DEVICE_MAJOR,
76     .base.minor_version = SPICE_INTERFACE_CHAR_DEVICE_MINOR,
77     .write              = vmc_write,
78     .read               = vmc_read,
79 };
80
81
82 static void vmc_register_interface(SpiceCharDriver *scd)
83 {
84     if (scd->active) {
85         return;
86     }
87     dprintf(scd, 1, "%s\n", __func__);
88     scd->sin.base.sif = &vmc_interface.base;
89     qemu_spice_add_interface(&scd->sin.base);
90     scd->active = true;
91     trace_spice_vmc_register_interface(scd);
92 }
93
94 static void vmc_unregister_interface(SpiceCharDriver *scd)
95 {
96     if (!scd->active) {
97         return;
98     }
99     dprintf(scd, 1, "%s\n", __func__);
100     spice_server_remove_interface(&scd->sin.base);
101     scd->active = false;
102     trace_spice_vmc_unregister_interface(scd);
103 }
104
105
106 static int spice_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
107 {
108     SpiceCharDriver *s = chr->opaque;
109
110     dprintf(s, 2, "%s: %d\n", __func__, len);
111     vmc_register_interface(s);
112     assert(s->datalen == 0);
113     if (s->bufsize < len) {
114         s->bufsize = len;
115         s->buffer = qemu_realloc(s->buffer, s->bufsize);
116     }
117     memcpy(s->buffer, buf, len);
118     s->datapos = s->buffer;
119     s->datalen = len;
120     spice_server_char_device_wakeup(&s->sin);
121     return len;
122 }
123
124 static void spice_chr_close(struct CharDriverState *chr)
125 {
126     SpiceCharDriver *s = chr->opaque;
127
128     printf("%s\n", __func__);
129     vmc_unregister_interface(s);
130     qemu_free(s);
131 }
132
133 static void spice_chr_guest_open(struct CharDriverState *chr)
134 {
135     SpiceCharDriver *s = chr->opaque;
136     vmc_register_interface(s);
137 }
138
139 static void spice_chr_guest_close(struct CharDriverState *chr)
140 {
141     SpiceCharDriver *s = chr->opaque;
142     vmc_unregister_interface(s);
143 }
144
145 static void print_allowed_subtypes(void)
146 {
147     const char** psubtype;
148     int i;
149
150     fprintf(stderr, "allowed names: ");
151     for(i=0, psubtype = spice_server_char_device_recognized_subtypes();
152         *psubtype != NULL; ++psubtype, ++i) {
153         if (i == 0) {
154             fprintf(stderr, "%s", *psubtype);
155         } else {
156             fprintf(stderr, ", %s", *psubtype);
157         }
158     }
159     fprintf(stderr, "\n");
160 }
161
162 CharDriverState *qemu_chr_open_spice(QemuOpts *opts)
163 {
164     CharDriverState *chr;
165     SpiceCharDriver *s;
166     const char* name = qemu_opt_get(opts, "name");
167     uint32_t debug = qemu_opt_get_number(opts, "debug", 0);
168     const char** psubtype = spice_server_char_device_recognized_subtypes();
169     const char *subtype = NULL;
170
171     if (name == NULL) {
172         fprintf(stderr, "spice-qemu-char: missing name parameter\n");
173         print_allowed_subtypes();
174         return NULL;
175     }
176     for(;*psubtype != NULL; ++psubtype) {
177         if (strcmp(name, *psubtype) == 0) {
178             subtype = *psubtype;
179             break;
180         }
181     }
182     if (subtype == NULL) {
183         fprintf(stderr, "spice-qemu-char: unsupported name\n");
184         print_allowed_subtypes();
185         return NULL;
186     }
187
188     chr = qemu_mallocz(sizeof(CharDriverState));
189     s = qemu_mallocz(sizeof(SpiceCharDriver));
190     s->chr = chr;
191     s->debug = debug;
192     s->active = false;
193     s->sin.subtype = subtype;
194     chr->opaque = s;
195     chr->chr_write = spice_chr_write;
196     chr->chr_close = spice_chr_close;
197     chr->chr_guest_open = spice_chr_guest_open;
198     chr->chr_guest_close = spice_chr_guest_close;
199
200     qemu_chr_generic_open(chr);
201
202     return chr;
203 }