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#include <poll.h>
#include <inttypes.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
struct _dnbd3_signal {
int read;
int write;
};
/*
* Generic (posix) implelentation of signals, using pipes.
* A struct containing both fds will be malloc()ed for each
* signal.
*/
dnbd3_signal_t* signal_new()
{
dnbd3_signal_t *ret = signal_newBlocking();
if ( ret == NULL ) return NULL;
fcntl( ret->read, F_SETFL, O_NONBLOCK );
fcntl( ret->write, F_SETFL, O_NONBLOCK );
return ret;
}
dnbd3_signal_t* signal_newBlocking()
{
int fds[2];
if ( pipe( fds ) == -1 ) return NULL;
dnbd3_signal_t* ret = malloc( sizeof(dnbd3_signal_t) );
ret->read = fds[0];
ret->write = fds[1];
return ret;
}
int signal_call(const dnbd3_signal_t* const signal)
{
if ( signal == NULL ) return SIGNAL_ERROR;
static char one = 1;
// Write one byte on every call, so the number of bytes read will
// match the number of events
return write( signal->write, &one, 1 ) > 0 ? SIGNAL_OK : SIGNAL_ERROR;
}
int signal_wait(const dnbd3_signal_t* const signal, int timeoutMs)
{
if ( signal == NULL ) return SIGNAL_ERROR;
struct pollfd ps = {
.fd = signal->read,
.events = POLLIN
};
int ret = poll( &ps, 1, timeoutMs );
if ( ret == 0 ) return SIGNAL_TIMEOUT;
if ( ret == -1 ) return SIGNAL_ERROR;
if ( ps.revents & ( POLLERR | POLLNVAL ) ) return SIGNAL_ERROR;
return signal_clear( signal );
}
int signal_clear(const dnbd3_signal_t* const signal)
{
if ( signal == NULL ) return SIGNAL_ERROR;
char throwaway[100];
ssize_t ret, total = 0;
do {
ret = read( signal->read, throwaway, sizeof throwaway );
if ( ret < 0 ) {
if ( errno == EAGAIN ) return (int)total;
return SIGNAL_ERROR;
}
total += ret;
} while ( (size_t)ret == sizeof throwaway );
return (int)total;
}
void signal_close(const dnbd3_signal_t* const signal)
{
close( signal->read );
close( signal->write );
free( (void*)signal );
}
int signal_getWaitFd(const dnbd3_signal_t* const signal)
{
if ( signal == NULL ) return -1;
return signal->read;
}
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