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48c9b433 KR |
1 | /* Utility for handling interrupted syscalls by signals. |
2 | ||
3 | Copyright (C) 2020 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #ifndef GDBSUPPORT_EINTR_H | |
21 | #define GDBSUPPORT_EINTR_H | |
22 | ||
23 | #include <cerrno> | |
24 | ||
25 | namespace gdb | |
26 | { | |
27 | /* Repeat a system call interrupted with a signal. | |
28 | ||
29 | A utility for handling interrupted syscalls, which return with error | |
30 | and set the errno to EINTR. The interrupted syscalls can be repeated, | |
31 | until successful completion. This utility avoids wrapping code with | |
32 | manual checks for such errors which are highly repetitive. | |
33 | ||
34 | For example, with: | |
35 | ||
36 | ssize_t ret; | |
37 | do | |
38 | { | |
39 | errno = 0; | |
40 | ret = ::write (pipe[1], "+", 1); | |
41 | } | |
42 | while (ret == -1 && errno == EINTR); | |
43 | ||
44 | You could wrap it by writing the wrapped form: | |
45 | ||
46 | ssize_t ret = gdb::handle_eintr<ssize_t> (-1, ::write, pipe[1], "+", 1); | |
47 | ||
48 | The RET typename specifies the return type of the wrapped system call, which | |
49 | is typically int or ssize_t. The R argument specifies the failure value | |
50 | indicating the interrupted syscall when calling the F function with | |
51 | the A... arguments. */ | |
52 | ||
53 | template <typename Ret, typename Fun, typename... Args> | |
54 | inline Ret handle_eintr (const Ret &R, const Fun &F, const Args &... A) | |
55 | { | |
56 | Ret ret; | |
57 | do | |
58 | { | |
59 | errno = 0; | |
60 | ret = F (A...); | |
61 | } | |
62 | while (ret == R && errno == EINTR); | |
63 | return ret; | |
64 | } | |
65 | } | |
66 | ||
67 | #endif /* GDBSUPPORT_EINTR_H */ |