alsa-utils/axfer/waiter-select.c
Takashi Sakamoto 257be19c47 axfer: allow to be compiled with glibc-2.11 or former
The program, axfer, was developed in userspace with glibc-2.28. This
userspace is mostly compliant to POSIX:2008 and some additional macros
for poll event are officially available. The glibc supports them as a
default since its v2.12 release. It will be failed to be compiled with
old glibc or the other libraries for C standard APIs.

One of the purpose of axfer is an better alternative of aplay. In a
point of the purpose, it's preferable to be compiled with the old
libraries.

This commit adds conditional macros to be compiled with libraries for
old compliance level of POSIX.

Reported-by: Jay Foster <jay@systech.com>
Fixes: fce16d9279 ('axfer: add an implementation of waiter for select(2)')
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2019-01-29 16:45:51 +01:00

110 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
//
// waiter-select.c - Waiter for event notification by select(2).
//
// Copyright (c) 2018 Takashi Sakamoto <o-takashi@sakamocchi.jp>
//
// Licensed under the terms of the GNU General Public License, version 2.
#include "waiter.h"
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/select.h>
// Except for POLLERR.
#ifdef POLLRDNORM
// This program is for userspace compliant to POSIX 2008 (IEEE 1003.1:2008).
// This is the default compliance level since glibc-2.12 or later.
# define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP)
# define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT)
#else
// However it's allowed to be for old compliance levels.
# define POLLIN_SET (POLLIN | POLLHUP)
# define POLLOUT_SET (POLLOUT)
#endif
#define POLLEX_SET (POLLPRI)
struct select_state {
fd_set rfds_rd;
fd_set rfds_wr;
fd_set rfds_ex;
};
static int select_prepare(struct waiter_context *waiter)
{
return 0;
}
static int select_wait_event(struct waiter_context *waiter, int timeout_msec)
{
struct select_state *state = waiter->private_data;
struct pollfd *pfd;
int fd_max;
struct timeval tv, *tv_ptr;
int i;
int err;
FD_ZERO(&state->rfds_rd);
FD_ZERO(&state->rfds_wr);
FD_ZERO(&state->rfds_ex);
fd_max = 0;
for (i = 0; i < waiter->pfd_count; ++i) {
pfd = &waiter->pfds[i];
if (pfd->events & POLLIN_SET)
FD_SET(pfd->fd, &state->rfds_rd);
if (pfd->events & POLLOUT_SET)
FD_SET(pfd->fd, &state->rfds_wr);
if (pfd->events & POLLEX_SET)
FD_SET(pfd->fd, &state->rfds_ex);
if (pfd->fd > fd_max)
fd_max = pfd->fd;
}
if (timeout_msec < 0) {
tv_ptr = NULL;
} else {
tv.tv_sec = 0;
tv.tv_usec = timeout_msec * 1000;
tv_ptr = &tv;
}
err = select(fd_max + 1, &state->rfds_rd, &state->rfds_wr,
&state->rfds_ex, tv_ptr);
if (err < 0)
return err;
for (i = 0; i < waiter->pfd_count; ++i) {
pfd = &waiter->pfds[i];
pfd->revents = 0;
if (FD_ISSET(pfd->fd, &state->rfds_rd))
pfd->revents |= POLLIN;
if (FD_ISSET(pfd->fd, &state->rfds_wr))
pfd->revents |= POLLOUT;
if (FD_ISSET(pfd->fd, &state->rfds_ex))
pfd->revents |= POLLHUP;
}
return 0;
}
static void select_release(struct waiter_context *waiter)
{
return;
}
const struct waiter_data waiter_select = {
.ops = {
.prepare = select_prepare,
.wait_event = select_wait_event,
.release = select_release,
},
.private_size = sizeof(struct select_state),
};