diff options
Diffstat (limited to 'src/shared/signal.c')
| -rw-r--r-- | src/shared/signal.c | 42 |
1 files changed, 32 insertions, 10 deletions
diff --git a/src/shared/signal.c b/src/shared/signal.c index a0697f8..e023c49 100644 --- a/src/shared/signal.c +++ b/src/shared/signal.c @@ -5,25 +5,38 @@ #include <errno.h> #include <unistd.h> -int signal_new() +/* + * Linux implementation of signals. + * Internally, eventfds are used for signalling, as they + * provide the least overhead. We don't allocate any struct + * ever, but cast the event fd+1 to dnbd3_signal_t* + * to save all the malloc() and free() calls. + */ + +dnbd3_signal_t* signal_new() { - return eventfd( 0, EFD_NONBLOCK ); + // On error, eventfd() returns -1, so essentially we return NULL on error. + // (Yes, NULL doesn't have to be 0 everywhere, but cmon) + return (dnbd3_signal_t*)(intptr_t)( eventfd( 0, EFD_NONBLOCK ) + 1 ); } -int signal_newBlocking() +dnbd3_signal_t* signal_newBlocking() { - return eventfd( 0, 0 ); + return (dnbd3_signal_t*)(intptr_t)( eventfd( 0, 0 ) + 1 ); } -int signal_call(int signalFd) +int signal_call(const dnbd3_signal_t* const signal) { - if ( signalFd < 0 ) return 0; + if ( signal == NULL ) return SIGNAL_ERROR; static uint64_t one = 1; + const int signalFd = ( (int)(intptr_t)signal ) - 1; return write( signalFd, &one, sizeof one ) == sizeof one; } -int signal_wait(int signalFd, int timeoutMs) +int signal_wait(const dnbd3_signal_t* const signal, int timeoutMs) { + if ( signal == NULL ) return SIGNAL_ERROR; + const int signalFd = ( (int)(intptr_t)signal ) - 1; struct pollfd ps = { .fd = signalFd, .events = POLLIN @@ -32,12 +45,14 @@ int signal_wait(int signalFd, int timeoutMs) if ( ret == 0 ) return SIGNAL_TIMEOUT; if ( ret == -1 ) return SIGNAL_ERROR; if ( ps.revents & ( POLLERR | POLLNVAL ) ) return SIGNAL_ERROR; - return signal_clear( signalFd ); + return signal_clear( signal ); } -int signal_clear(int signalFd) +int signal_clear(const dnbd3_signal_t* const signal) { + if ( signal == NULL ) return SIGNAL_ERROR; uint64_t ret; + const int signalFd = ( (int)(intptr_t)signal ) - 1; if ( read( signalFd, &ret, sizeof ret ) != sizeof ret ) { if ( errno == EAGAIN ) return 0; return SIGNAL_ERROR; @@ -45,8 +60,15 @@ int signal_clear(int signalFd) return (int)ret; } -void signal_close(int signalFd) +void signal_close(const dnbd3_signal_t* const signal) { + const int signalFd = ( (int)(intptr_t)signal ) - 1; close( signalFd ); } +int signal_getWaitFd(const dnbd3_signal_t* const signal) +{ + const int signalFd = ( (int)(intptr_t)signal ) - 1; + return signalFd; +} + |