diff options
Diffstat (limited to 'iolooper-select.c')
-rw-r--r-- | iolooper-select.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/iolooper-select.c b/iolooper-select.c new file mode 100644 index 0000000..74a5a3a --- /dev/null +++ b/iolooper-select.c @@ -0,0 +1,176 @@ +#include "iolooper.h" +#include "qemu-common.h" + +/* An implementation of iolooper.h based on Unix select() */ +#ifdef _WIN32 +# include <winsock2.h> +#else +# include <sys/types.h> +# include <sys/select.h> +#endif + +struct IoLooper { + fd_set reads[1]; + fd_set writes[1]; + fd_set reads_result[1]; + fd_set writes_result[1]; + int max_fd; + int max_fd_valid; +}; + +IoLooper* +iolooper_new(void) +{ + IoLooper* iol = qemu_malloc(sizeof(*iol)); + iolooper_reset(iol); + return iol; +} + +void +iolooper_free( IoLooper* iol ) +{ + qemu_free(iol); +} + +void +iolooper_reset( IoLooper* iol ) +{ + FD_ZERO(iol->reads); + FD_ZERO(iol->writes); + iol->max_fd = -1; + iol->max_fd_valid = 1; +} + +static void +iolooper_add_fd( IoLooper* iol, int fd ) +{ + if (iol->max_fd_valid && fd > iol->max_fd) { + iol->max_fd = fd; + } +} + +static void +iolooper_del_fd( IoLooper* iol, int fd ) +{ + if (iol->max_fd_valid && fd == iol->max_fd) + iol->max_fd_valid = 0; +} + +static int +iolooper_fd_count( IoLooper* iol ) +{ + int max_fd = iol->max_fd; + int fd; + + if (iol->max_fd_valid) + return max_fd + 1; + + /* recompute max fd */ + for (fd = 0; fd < FD_SETSIZE; fd++) { + if (!FD_ISSET(fd, iol->reads) && !FD_ISSET(fd, iol->writes)) + continue; + + max_fd = fd; + } + iol->max_fd = max_fd; + iol->max_fd_valid = 1; + + return max_fd + 1; +} + +void +iolooper_add_read( IoLooper* iol, int fd ) +{ + if (fd >= 0) { + iolooper_add_fd(iol, fd); + FD_SET(fd, iol->reads); + } +} + +void +iolooper_add_write( IoLooper* iol, int fd ) +{ + if (fd >= 0) { + iolooper_add_fd(iol, fd); + FD_SET(fd, iol->writes); + } +} + +void +iolooper_del_read( IoLooper* iol, int fd ) +{ + if (fd >= 0) { + iolooper_del_fd(iol, fd); + FD_CLR(fd, iol->reads); + } +} + +void +iolooper_del_write( IoLooper* iol, int fd ) +{ + if (fd >= 0) { + iolooper_del_fd(iol, fd); + FD_CLR(fd, iol->reads); + } +} + +int +iolooper_poll( IoLooper* iol ) +{ + int count = iolooper_fd_count(iol); + int ret; + fd_set errs; + + if (count == 0) + return 0; + + FD_ZERO(&errs); + + do { + struct timeval tv; + + tv.tv_sec = tv.tv_usec = 0; + + iol->reads_result[0] = iol->reads[0]; + iol->writes_result[0] = iol->writes[0]; + + ret = select( count, iol->reads_result, iol->writes_result, &errs, &tv); + } while (ret < 0 && errno == EINTR); + + return ret; +} + +int +iolooper_wait( IoLooper* iol, int64_t duration ) +{ + int count = iolooper_fd_count(iol); + int ret; + fd_set errs; + + if (count == 0) + return 0; + + FD_ZERO(&errs); + + do { + iol->reads_result[0] = iol->reads[0]; + iol->writes_result[0] = iol->writes[0]; + + ret = select( count, iol->reads_result, iol->writes_result, &errs, NULL); + } while (ret < 0 && errno == EINTR); + + return ret; +} + + +int +iolooper_is_read( IoLooper* iol, int fd ) +{ + return FD_ISSET(fd, iol->reads_result); +} + +int +iolooper_is_write( IoLooper* iol, int fd ) +{ + return FD_ISSET(fd, iol->writes_result); +} |