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shutdown: Use RAII TokenPipe in shutdown

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This commit is contained in:
Wladimir J. van der Laan 2021-01-26 19:34:47 +01:00
parent 612f746a8f
commit c3e6fdee6d
1 changed files with 17 additions and 39 deletions
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56
src/shutdown.cpp
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@ -5,16 +5,15 @@
#include <shutdown.h>
#include <logging.h>
#include <util/tokenpipe.h>
#include <config/bitcoin-config.h>
#include <assert.h>
#include <atomic>
#ifdef WIN32
#include <condition_variable>
#else
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#endif
static std::atomic<bool> fRequestShutdown(false);
@ -24,25 +23,18 @@ std::mutex g_shutdown_mutex;
std::condition_variable g_shutdown_cv;
#else
/** On UNIX-like operating systems use the self-pipe trick.
* Index 0 will be the read end of the pipe, index 1 the write end.
*/
static int g_shutdown_pipe[2] = {-1, -1};
static TokenPipeEnd g_shutdown_r;
static TokenPipeEnd g_shutdown_w;
#endif
bool InitShutdownState()
{
#ifndef WIN32
#if HAVE_O_CLOEXEC && HAVE_DECL_PIPE2
// If we can, make sure that the file descriptors are closed on exec()
// to prevent interference.
if (pipe2(g_shutdown_pipe, O_CLOEXEC) != 0) {
return false;
}
#else
if (pipe(g_shutdown_pipe) != 0) {
return false;
}
#endif
std::optional<TokenPipe> pipe = TokenPipe::Make();
if (!pipe) return false;
g_shutdown_r = pipe->TakeReadEnd();
g_shutdown_w = pipe->TakeWriteEnd();
#endif
return true;
}
@ -59,17 +51,10 @@ void StartShutdown()
// case of a reentrant signal.
if (!fRequestShutdown.exchange(true)) {
// Write an arbitrary byte to the write end of the shutdown pipe.
const char token = 'x';
while (true) {
int result = write(g_shutdown_pipe[1], &token, 1);
if (result < 0) {
// Failure. It's possible that the write was interrupted by another signal.
// Other errors are unexpected here.
assert(errno == EINTR);
} else {
assert(result == 1);
break;
}
int res = g_shutdown_w.TokenWrite('x');
if (res != 0) {
LogPrintf("Sending shutdown token failed\n");
assert(0);
}
}
#endif
@ -96,17 +81,10 @@ void WaitForShutdown()
std::unique_lock<std::mutex> lk(g_shutdown_mutex);
g_shutdown_cv.wait(lk, [] { return fRequestShutdown.load(); });
#else
char token;
while (true) {
int result = read(g_shutdown_pipe[0], &token, 1);
if (result < 0) {
// Failure. Check if the read was interrupted by a signal.
// Other errors are unexpected here.
assert(errno == EINTR);
} else {
assert(result == 1);
break;
}
int res = g_shutdown_r.TokenRead();
if (res != 'x') {
LogPrintf("Reading shutdown token failed\n");
assert(0);
}
#endif
}