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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
/********************************************************************
* Description: recvn.c
* Provides a C file for the recvn function from the book Advanced
* Programming in the UNIX Environment by Richard Stevens.
* The recvn function is called repeatedly until n bytes have been
* received from the file descriptor. It uses select and FIONREAD
* checks ahead of time to guarantee that even if the socket is
* blocking the timeout will be enforced. To retry a socket to for
* the data missed during past timeouts the application should pass
* recvn the same buffer and address of a variable storing the number
* of bytes read on previous attempts.
*
* Derived from a work by Fred Proctor & Will Shackleford
*
* Author:
* License: LGPL Version 2
* System: Linux
*
* Copyright (c) 2004 All rights reserved.
*
* Last change:
********************************************************************/
#include "recvn.h" /* recvn(int, void *, int, double) */
#include <stddef.h> /* size_t */
#include <errno.h> /* errno */
#include <sys/types.h> /* typedef fd_set, FD_ZERO, FD_SET */
#include <sys/ioctl.h> /* FIONREAD */
#include <sys/socket.h> /* recv() */
#include <sys/time.h> /* struct timeval */
#include <stdlib.h> /* malloc(), free() */
#include <string.h> /* strerror() */
#include <math.h> /* modf() */
#include "rcs_print.hh" /* rcs_print_error() */
#include "_timer.h" /* etime(), esleep() */
int recvn_timedout = 0;
int print_recvn_timeout_errors = 1;
/* Read "n" bytes from a descriptor. */
int recvn(int fd, void *vptr, int n, int flags, double _timeout,
int *bytes_read_ptr)
{
int nleft, nrecv;
char *ptr;
double start_time;
struct timeval timeout_tv;
fd_set recv_fd_set;
int bytes_ready;
int bytes_to_read;
if (etime_disabled) {
_timeout = -1.0;
}
bytes_ready = 0;
timeout_tv.tv_sec = (long) _timeout;
timeout_tv.tv_usec = (long) (_timeout * 1000000.0);
if (timeout_tv.tv_usec >= 1000000) {
timeout_tv.tv_usec = timeout_tv.tv_usec % 1000000;
}
FD_ZERO(&recv_fd_set);
FD_SET(fd, &recv_fd_set);
recvn_timedout = 0;
ptr = (char *) vptr;
nleft = n;
if (NULL != bytes_read_ptr) {
if (*bytes_read_ptr >= n) {
rcs_print_error
("recvn: Invalid parameter -- (*bytes_read_ptr = %d) must be less than (n = %d).\n",
*bytes_read_ptr, n);
return -1;
}
if (*bytes_read_ptr < 0) {
rcs_print_error
("recvn: Invalid parameter -- (*bytes_read_ptr = %d) must be greater than or equal to zero.\n",
*bytes_read_ptr);
return -1;
}
ptr += *bytes_read_ptr;
nleft -= *bytes_read_ptr;
}
start_time = etime();
while (nleft > 0) {
if (_timeout > 0.0) {
double timeleft;
timeleft = start_time + _timeout - etime();
if (timeleft <= 0.0) {
if (print_recvn_timeout_errors) {
rcs_print_error("Recv timed out.\n");
if (NULL == bytes_read_ptr) {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f) failed.\n",
fd, vptr, n, flags, _timeout);
} else {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f,bytes_read=%d) failed.\n",
fd, vptr, n, flags, _timeout, *bytes_read_ptr);
}
}
recvn_timedout = 1;
if (NULL != bytes_read_ptr) {
*bytes_read_ptr = (n - nleft);
}
return -1;
}
timeout_tv.tv_sec = (long) timeleft;
timeout_tv.tv_usec = (long) (timeleft * 1000000.0);
if (timeout_tv.tv_usec >= 1000000) {
timeout_tv.tv_usec = timeout_tv.tv_usec % 1000000;
}
switch (select(fd + 1, &recv_fd_set, (fd_set *) NULL,
(fd_set *) NULL, &timeout_tv)) {
case -1:
rcs_print_error("Error in select: %d -> %s\n", errno,
strerror(errno));
if (NULL == bytes_read_ptr) {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f) failed.\n",
fd, vptr, n, flags, _timeout);
} else {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f,bytes_read=%d) failed.\n",
fd, vptr, n, flags, _timeout, *bytes_read_ptr);
}
return -1;
case 0:
if (print_recvn_timeout_errors) {
rcs_print_error("Recv timed out.\n");
if (NULL == bytes_read_ptr) {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f) failed.\n",
fd, vptr, n, flags, _timeout);
} else {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f,bytes_read=%d) failed.\n",
fd, vptr, n, flags, _timeout, *bytes_read_ptr);
}
}
recvn_timedout = 1;
if (NULL != bytes_read_ptr) {
*bytes_read_ptr = (n - nleft);
}
return -1;
default:
break;
}
bytes_ready = 0;
ioctl(fd, FIONREAD, (caddr_t) & bytes_ready);
bytes_to_read = (nleft <= bytes_ready) ? nleft : bytes_ready;
} else {
bytes_to_read = nleft;
}
nrecv = 0;
if (bytes_to_read > 0) {
if ((nrecv = recv(fd, ptr, bytes_to_read, flags)) == -1) {
if (errno == EWOULDBLOCK) {
if (fabs(_timeout) < 1e-6) {
recvn_timedout = 1;
if (NULL != bytes_read_ptr) {
*bytes_read_ptr = (n - nleft);
}
return -1;
}
} else {
rcs_print_error("Recv error: %d = %s\n", errno,
strerror(errno));
if (NULL == bytes_read_ptr) {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f) failed.\n",
fd, vptr, n, flags, _timeout);
} else {
rcs_print_error
("recvn(fd=%d, vptr=%p, int n=%d, int flags=%d, double _timeout=%f,bytes_read=%d) failed.\n",
fd, vptr, n, flags, _timeout, *bytes_read_ptr);
}
if (NULL != bytes_read_ptr) {
*bytes_read_ptr = (n - nleft);
}
return (-1); /* error, return < 0 */
}
nrecv = 0;
} else if (nrecv == 0) {
rcs_print_error("recvn: Premature EOF recieved.\n");
return (-2);
}
}
nleft -= nrecv;
ptr += nrecv;
if (nleft > 0 && _timeout > 0.0) {
esleep(0.001);
if (etime() - start_time > _timeout) {
rcs_print_error("Recv timed out.\n");
recvn_timedout = 1;
if (NULL != bytes_read_ptr) {
*bytes_read_ptr = (n - nleft);
}
return (-1);
}
}
}
rcs_print_debug(PRINT_SOCKET_READ_SIZE, "read %d bytes from %d\n", n, fd);
if (NULL != bytes_read_ptr) {
*bytes_read_ptr = (n - nleft);
}
return (n - nleft); /* return >= 0 */
}
|
