1 | /* Linux select implementation. |
2 | Copyright (C) 2017-2018 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library. If not, see |
17 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <sys/time.h> |
20 | #include <sys/types.h> |
21 | #include <sys/select.h> |
22 | #include <errno.h> |
23 | #include <sysdep-cancel.h> |
24 | |
25 | /* Check the first NFDS descriptors each in READFDS (if not NULL) for read |
26 | readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS |
27 | (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out |
28 | after waiting the interval specified therein. Returns the number of ready |
29 | descriptors, or -1 for errors. */ |
30 | |
31 | #ifdef __NR__newselect |
32 | # undef __NR_select |
33 | # define __NR_select __NR__newselect |
34 | #endif |
35 | |
36 | int |
37 | __select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, |
38 | struct timeval *timeout) |
39 | { |
40 | #ifdef __NR_select |
41 | return SYSCALL_CANCEL (select, nfds, readfds, writefds, exceptfds, |
42 | timeout); |
43 | #else |
44 | int result; |
45 | struct timespec ts, *tsp = NULL; |
46 | |
47 | if (timeout) |
48 | { |
49 | TIMEVAL_TO_TIMESPEC (timeout, &ts); |
50 | tsp = &ts; |
51 | } |
52 | |
53 | result = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, tsp, |
54 | NULL); |
55 | |
56 | if (timeout) |
57 | { |
58 | /* Linux by default will update the timeout after a pselect6 syscall |
59 | (though the pselect() glibc call suppresses this behavior). |
60 | Since select() on Linux has the same behavior as the pselect6 |
61 | syscall, we update the timeout here. */ |
62 | TIMESPEC_TO_TIMEVAL (timeout, &ts); |
63 | } |
64 | |
65 | return result; |
66 | #endif |
67 | } |
68 | libc_hidden_def (__select) |
69 | |
70 | weak_alias (__select, select) |
71 | weak_alias (__select, __libc_select) |
72 | |