source: branches/samba-3.0/examples/libsmbclient/smbwrapper/select.c

Last change on this file was 1, checked in by Paul Smedley, 18 years ago

Initial code import
File size: 3.9 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 2 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, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21*/
22
23/*
24 * WHY THIS FILE?
25 *
26 * This file implements the two functions in the select() family, as required
27 * by samba. The samba native functions, though, implement a pipe to help
28 * alleviate a deadlock problem, but which creates problems of its own (the
29 * timeout stops working correctly). Those functions also require that all
30 * signal handlers call a function which writes to the pipe -- a task which is
31 * difficult to do in the smbwrapper environment.
32 */
33
34
35#include <sys/select.h>
36#include <errno.h>
37#include <stdio.h>
38
39int sys_select(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval)
40{
41 int ret;
42 fd_set *readfds2, readfds_buf;
43
44 /* If readfds is NULL we need to provide our own set. */
45 if (readfds) {
46 readfds2 = readfds;
47 } else {
48 readfds2 = &readfds_buf;
49 FD_ZERO(readfds2);
50 }
51
52 errno = 0;
53 ret = select(maxfd,readfds2,writefds,errorfds,tval);
54
55 if (ret <= 0) {
56 FD_ZERO(readfds2);
57 if (writefds)
58 FD_ZERO(writefds);
59 if (errorfds)
60 FD_ZERO(errorfds);
61 }
62
63 return ret;
64}
65
66/*******************************************************************
67 Similar to sys_select() but catch EINTR and continue.
68 This is what sys_select() used to do in Samba.
69********************************************************************/
70
71int sys_select_intr(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, struct timeval *tval)
72{
73 int ret;
74 fd_set *readfds2, readfds_buf, *writefds2, writefds_buf, *errorfds2, errorfds_buf;
75 struct timeval tval2, *ptval, end_time, now_time;
76 extern void GetTimeOfDay(struct timeval *tval);
77
78 readfds2 = (readfds ? &readfds_buf : NULL);
79 writefds2 = (writefds ? &writefds_buf : NULL);
80 errorfds2 = (errorfds ? &errorfds_buf : NULL);
81 if (tval) {
82 GetTimeOfDay(&end_time);
83 end_time.tv_sec += tval->tv_sec;
84 end_time.tv_usec += tval->tv_usec;
85 end_time.tv_sec += end_time.tv_usec / 1000000;
86 end_time.tv_usec %= 1000000;
87 ptval = &tval2;
88 } else {
89 ptval = NULL;
90 }
91
92 do {
93 if (readfds)
94 readfds_buf = *readfds;
95 if (writefds)
96 writefds_buf = *writefds;
97 if (errorfds)
98 errorfds_buf = *errorfds;
99 if (tval) {
100 GetTimeOfDay(&now_time);
101 tval2.tv_sec = end_time.tv_sec - now_time.tv_sec;
102 tval2.tv_usec = end_time.tv_usec - now_time.tv_usec;
103 if ((signed long) tval2.tv_usec < 0) {
104 tval2.tv_usec += 1000000;
105 tval2.tv_sec--;
106 }
107 if ((signed long) tval2.tv_sec < 0) {
108 ret = 0;
109 break; /* time has already elapsed */
110 }
111 }
112
113 ret = sys_select(maxfd, readfds2, writefds2, errorfds2, ptval);
114 } while (ret == -1 && errno == EINTR);
115
116 if (readfds)
117 *readfds = readfds_buf;
118 if (writefds)
119 *writefds = writefds_buf;
120 if (errorfds)
121 *errorfds = errorfds_buf;
122
123 return ret;
124}
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