1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/*
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <telephony/record_stream.h>
#include <string.h>
#include <stdint.h>
#if defined(_WIN32)
#include <winsock2.h> /* for ntohl */
#else
#include <netinet/in.h>
#endif
#define HEADER_SIZE 4
struct RecordStream {
int fd;
size_t maxRecordLen;
unsigned char *buffer;
unsigned char *unconsumed;
unsigned char *read_end;
unsigned char *buffer_end;
};
extern RecordStream *record_stream_new(int fd, size_t maxRecordLen)
{
RecordStream *ret;
assert (maxRecordLen <= 0xffff);
ret = (RecordStream *)calloc(1, sizeof(RecordStream));
ret->fd = fd;
ret->maxRecordLen = maxRecordLen;
ret->buffer = (unsigned char *)malloc (maxRecordLen + HEADER_SIZE);
ret->unconsumed = ret->buffer;
ret->read_end = ret->buffer;
ret->buffer_end = ret->buffer + maxRecordLen + HEADER_SIZE;
return ret;
}
extern void record_stream_free(RecordStream *rs)
{
free(rs->buffer);
free(rs);
}
/* returns NULL; if there isn't a full record in the buffer */
static unsigned char * getEndOfRecord (unsigned char *p_begin,
unsigned char *p_end)
{
size_t len;
unsigned char * p_ret;
if (p_end < p_begin + HEADER_SIZE) {
return NULL;
}
//First four bytes are length
len = ntohl(*((uint32_t *)p_begin));
p_ret = p_begin + HEADER_SIZE + len;
if (p_end < p_ret) {
return NULL;
}
return p_ret;
}
static void *getNextRecord (RecordStream *p_rs, size_t *p_outRecordLen)
{
unsigned char *record_start, *record_end;
record_end = getEndOfRecord (p_rs->unconsumed, p_rs->read_end);
if (record_end != NULL) {
/* one full line in the buffer */
record_start = p_rs->unconsumed + HEADER_SIZE;
p_rs->unconsumed = record_end;
*p_outRecordLen = record_end - record_start;
return record_start;
}
return NULL;
}
/**
* Reads the next record from stream fd
* Records are prefixed by a 16-bit big endian length value
* Records may not be larger than maxRecordLen
*
* Doesn't guard against EINTR
*
* p_outRecord and p_outRecordLen may not be NULL
*
* Return 0 on success, -1 on fail
* Returns 0 with *p_outRecord set to NULL on end of stream
* Returns -1 / errno = EAGAIN if it needs to read again
*/
int record_stream_get_next (RecordStream *p_rs, void ** p_outRecord,
size_t *p_outRecordLen)
{
void *ret;
ssize_t countRead;
/* is there one record already in the buffer? */
ret = getNextRecord (p_rs, p_outRecordLen);
if (ret != NULL) {
*p_outRecord = ret;
return 0;
}
// if the buffer is full and we don't have a full record
if (p_rs->unconsumed == p_rs->buffer
&& p_rs->read_end == p_rs->buffer_end
) {
// this should never happen
//ALOGE("max record length exceeded\n");
assert (0);
errno = EFBIG;
return -1;
}
if (p_rs->unconsumed != p_rs->buffer) {
// move remainder to the beginning of the buffer
size_t toMove;
toMove = p_rs->read_end - p_rs->unconsumed;
if (toMove) {
memmove(p_rs->buffer, p_rs->unconsumed, toMove);
}
p_rs->read_end = p_rs->buffer + toMove;
p_rs->unconsumed = p_rs->buffer;
}
countRead = read (p_rs->fd, p_rs->read_end, p_rs->buffer_end - p_rs->read_end);
if (countRead <= 0) {
/* note: end-of-stream drops through here too */
*p_outRecord = NULL;
return countRead;
}
p_rs->read_end += countRead;
ret = getNextRecord (p_rs, p_outRecordLen);
if (ret == NULL) {
/* not enough of a buffer to for a whole command */
errno = EAGAIN;
return -1;
}
*p_outRecord = ret;
return 0;
}
|
