1 | #pragma once |
2 | |
3 | #include <signal.h> |
4 | #include <errno.h> |
5 | #include <Common/Exception.h> |
6 | |
7 | |
8 | namespace DB |
9 | { |
10 | |
11 | namespace ErrorCodes |
12 | { |
13 | extern const int CANNOT_MANIPULATE_SIGSET; |
14 | extern const int CANNOT_WAIT_FOR_SIGNAL; |
15 | extern const int CANNOT_BLOCK_SIGNAL; |
16 | extern const int CANNOT_UNBLOCK_SIGNAL; |
17 | } |
18 | |
19 | #ifdef __APPLE__ |
20 | // We only need to support timeout = {0, 0} at this moment |
21 | static int sigtimedwait(const sigset_t *set, siginfo_t *info, const struct timespec * /*timeout*/) |
22 | { |
23 | sigset_t pending; |
24 | int signo; |
25 | sigpending(&pending); |
26 | |
27 | for (signo = 1; signo < NSIG; ++signo) |
28 | { |
29 | if (sigismember(set, signo) && sigismember(&pending, signo)) |
30 | { |
31 | sigwait(set, &signo); |
32 | if (info) |
33 | { |
34 | memset(info, 0, sizeof *info); |
35 | info->si_signo = signo; |
36 | } |
37 | return signo; |
38 | } |
39 | } |
40 | errno = EAGAIN; |
41 | |
42 | return -1; |
43 | } |
44 | #endif |
45 | |
46 | |
47 | /** As long as there exists an object of this class - it blocks the INT signal, at the same time it lets you know if it came. |
48 | * This is necessary so that you can interrupt the execution of the request with Ctrl+C. |
49 | * Use only one instance of this class at a time. |
50 | * If `check` method returns true (the signal has arrived), the next call will wait for the next signal. |
51 | */ |
52 | class InterruptListener |
53 | { |
54 | private: |
55 | bool active; |
56 | sigset_t sig_set; |
57 | |
58 | public: |
59 | InterruptListener() : active(false) |
60 | { |
61 | if (sigemptyset(&sig_set) |
62 | || sigaddset(&sig_set, SIGINT)) |
63 | throwFromErrno("Cannot manipulate with signal set." , ErrorCodes::CANNOT_MANIPULATE_SIGSET); |
64 | |
65 | block(); |
66 | } |
67 | |
68 | ~InterruptListener() |
69 | { |
70 | unblock(); |
71 | } |
72 | |
73 | bool check() |
74 | { |
75 | if (!active) |
76 | return false; |
77 | |
78 | timespec timeout = { 0, 0 }; |
79 | |
80 | if (-1 == sigtimedwait(&sig_set, nullptr, &timeout)) |
81 | { |
82 | if (errno == EAGAIN) |
83 | return false; |
84 | else |
85 | throwFromErrno("Cannot poll signal (sigtimedwait)." , ErrorCodes::CANNOT_WAIT_FOR_SIGNAL); |
86 | } |
87 | |
88 | return true; |
89 | } |
90 | |
91 | void block() |
92 | { |
93 | if (!active) |
94 | { |
95 | if (pthread_sigmask(SIG_BLOCK, &sig_set, nullptr)) |
96 | throwFromErrno("Cannot block signal." , ErrorCodes::CANNOT_BLOCK_SIGNAL); |
97 | |
98 | active = true; |
99 | } |
100 | } |
101 | |
102 | /// You can stop blocking the signal earlier than in the destructor. |
103 | void unblock() |
104 | { |
105 | if (active) |
106 | { |
107 | if (pthread_sigmask(SIG_UNBLOCK, &sig_set, nullptr)) |
108 | throwFromErrno("Cannot unblock signal." , ErrorCodes::CANNOT_UNBLOCK_SIGNAL); |
109 | |
110 | active = false; |
111 | } |
112 | } |
113 | }; |
114 | |
115 | } |
116 | |