source: branches/samba-3.2.x/examples/libsmbclient/smbwrapper/select.c

Last change on this file was 133, checked in by Paul Smedley, 17 years ago

Update trunk to 3.2.0pre3
File size: 3.8 KB
Line 
1/*
2 Unix SMB/Netbios implementation.
3 Version 3.0
4 Samba select/poll implementation
5 Copyright (C) Andrew Tridgell 1992-1998
6 Copyright (C) Derrell Lipman 2003-2005
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
20*/
21
22/*
23 * WHY THIS FILE?
24 *
25 * This file implements the two functions in the select() family, as required
26 * by samba. The samba native functions, though, implement a pipe to help
27 * alleviate a deadlock problem, but which creates problems of its own (the
28 * timeout stops working correctly). Those functions also require that all
29 * signal handlers call a function which writes to the pipe -- a task which is
30 * difficult to do in the smbwrapper environment.
31 */
32
33
34#include <sys/select.h>
35#include <errno.h>
36#include <stdio.h>
37
38int sys_select(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval)
39{
40 int ret;
41 fd_set *readfds2, readfds_buf;
42
43 /* If readfds is NULL we need to provide our own set. */
44 if (readfds) {
45 readfds2 = readfds;
46 } else {
47 readfds2 = &readfds_buf;
48 FD_ZERO(readfds2);
49 }
50
51 errno = 0;
52 ret = select(maxfd,readfds2,writefds,errorfds,tval);
53
54 if (ret <= 0) {
55 FD_ZERO(readfds2);
56 if (writefds)
57 FD_ZERO(writefds);
58 if (errorfds)
59 FD_ZERO(errorfds);
60 }
61
62 return ret;
63}
64
65/*******************************************************************
66 Similar to sys_select() but catch EINTR and continue.
67 This is what sys_select() used to do in Samba.
68********************************************************************/
69
70int sys_select_intr(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval)
71{
72 int ret;
73 fd_set *readfds2, readfds_buf, *writefds2, writefds_buf, *errorfds2, errorfds_buf;
74 struct timeval tval2, *ptval, end_time, now_time;
75
76 readfds2 = (readfds ? &readfds_buf : NULL);
77 writefds2 = (writefds ? &writefds_buf : NULL);
78 errorfds2 = (errorfds ? &errorfds_buf : NULL);
79 if (tval) {
80 gettimeofday(&end_time, NULL);
81 end_time.tv_sec += tval->tv_sec;
82 end_time.tv_usec += tval->tv_usec;
83 end_time.tv_sec += end_time.tv_usec / 1000000;
84 end_time.tv_usec %= 1000000;
85 ptval = &tval2;
86 } else {
87 ptval = NULL;
88 }
89
90 do {
91 if (readfds)
92 readfds_buf = *readfds;
93 if (writefds)
94 writefds_buf = *writefds;
95 if (errorfds)
96 errorfds_buf = *errorfds;
97 if (tval) {
98 gettimeofday(&now_time, NULL);
99 tval2.tv_sec = end_time.tv_sec - now_time.tv_sec;
100 tval2.tv_usec = end_time.tv_usec - now_time.tv_usec;
101 if ((signed long) tval2.tv_usec < 0) {
102 tval2.tv_usec += 1000000;
103 tval2.tv_sec--;
104 }
105 if ((signed long) tval2.tv_sec < 0) {
106 ret = 0;
107 break; /* time has already elapsed */
108 }
109 }
110
111 ret = sys_select(maxfd, readfds2, writefds2, errorfds2, ptval);
112 } while (ret == -1 && errno == EINTR);
113
114 if (readfds)
115 *readfds = readfds_buf;
116 if (writefds)
117 *writefds = writefds_buf;
118 if (errorfds)
119 *errorfds = errorfds_buf;
120
121 return ret;
122}
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