This commit adds support of waiter for Linux specific epoll(7) system call. For portability to the other Unix-like systems such as xBSD, modification of Makefile.am may be required for conditional build, but this commit includes no changes for it.
Below lines are examples to use this option: $ axfer transfer --waiter-type=epoll -M -P -d 2 -D hw:0,3 /dev/urandom -f dat -vvv $ axfer transfer --waiter-type=epoll -M -C -d 2 -D hw:1,0 /dev/null -r 48000 -vvv
Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- axfer/Makefile.am | 3 +- axfer/waiter-epoll.c | 107 +++++++++++++++++++++++++++++++++++++++++++ axfer/waiter.c | 2 + axfer/waiter.h | 2 + 4 files changed, 113 insertions(+), 1 deletion(-) create mode 100644 axfer/waiter-epoll.c
diff --git a/axfer/Makefile.am b/axfer/Makefile.am index 867007b..ab1d0b4 100644 --- a/axfer/Makefile.am +++ b/axfer/Makefile.am @@ -52,4 +52,5 @@ axfer_SOURCES = \ waiter.h \ waiter.c \ waiter-poll.c \ - waiter-select.c + waiter-select.c \ + waiter-epoll.c diff --git a/axfer/waiter-epoll.c b/axfer/waiter-epoll.c new file mode 100644 index 00000000..8f084f1 --- /dev/null +++ b/axfer/waiter-epoll.c @@ -0,0 +1,107 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// waiter-epoll.c - Waiter for event notification by epoll(7). +// +// 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 "misc.h" + +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <errno.h> +#include <sys/types.h> +#include <sys/epoll.h> + +struct epoll_state { + int epfd; + struct epoll_event *events; + unsigned int ev_count; +}; + +static int epoll_prepare(struct waiter_context *waiter) +{ + struct epoll_state *state = waiter->private_data; + int i; + + state->ev_count = waiter->pfd_count; + state->events = calloc(state->ev_count, sizeof(*state->events)); + if (state->events == NULL) + return -ENOMEM; + + state->epfd = epoll_create(1); + if (state->epfd < 0) + return -errno; + + for (i = 0; i < waiter->pfd_count; ++i) { + struct epoll_event ev = { + .data.fd = waiter->pfds[i].fd, + .events = waiter->pfds[i].events, + }; + if (epoll_ctl(state->epfd, EPOLL_CTL_ADD, ev.data.fd, &ev) < 0) + return -errno; + } + + return 0; +} + +static int epoll_wait_event(struct waiter_context *waiter, int timeout_msec) +{ + struct epoll_state *state = waiter->private_data; + unsigned int ev_count; + int i, j; + int err; + + memset(state->events, 0, state->ev_count * sizeof(*state->events)); + err = epoll_wait(state->epfd, state->events, state->ev_count, + timeout_msec); + if (err < 0) + return -errno; + ev_count = (unsigned int)err; + + if (ev_count > 0) { + // Reconstruct data of pollfd structure. + for (i = 0; i < ev_count; ++i) { + struct epoll_event *ev = &state->events[i]; + for (j = 0; j < waiter->pfd_count; ++j) { + if (waiter->pfds[i].fd == ev->data.fd) { + waiter->pfds[i].revents = ev->events; + break; + } + } + } + } + + return ev_count; +} + +static void epoll_release(struct waiter_context *waiter) +{ + struct epoll_state *state = waiter->private_data; + int i; + + for (i = 0; i < waiter->pfd_count; ++i) { + int fd = waiter->pfds[i].fd; + epoll_ctl(state->epfd, EPOLL_CTL_DEL, fd, NULL); + } + + free(state->events); + state->events = NULL; + + close(state->epfd); + + state->ev_count = 0; + state->epfd = 0; +} + +const struct waiter_data waiter_epoll = { + .ops = { + .prepare = epoll_prepare, + .wait_event = epoll_wait_event, + .release = epoll_release, + }, + .private_size = sizeof(struct epoll_state), +}; diff --git a/axfer/waiter.c b/axfer/waiter.c index 08428e3..1e9c811 100644 --- a/axfer/waiter.c +++ b/axfer/waiter.c @@ -18,6 +18,7 @@ static const char *const waiter_type_labels[] = { [WAITER_TYPE_DEFAULT] = "default", [WAITER_TYPE_POLL] = "poll", [WAITER_TYPE_SELECT] = "select", + [WAITER_TYPE_EPOLL] = "epoll", };
enum waiter_type waiter_type_from_label(const char *label) @@ -46,6 +47,7 @@ int waiter_context_init(struct waiter_context *waiter, } entries[] = { {WAITER_TYPE_POLL, &waiter_poll}, {WAITER_TYPE_SELECT, &waiter_select}, + {WAITER_TYPE_EPOLL, &waiter_epoll}, }; int i;
diff --git a/axfer/waiter.h b/axfer/waiter.h index fec16b7..db18e33 100644 --- a/axfer/waiter.h +++ b/axfer/waiter.h @@ -15,6 +15,7 @@ enum waiter_type { WAITER_TYPE_DEFAULT = 0, WAITER_TYPE_POLL, WAITER_TYPE_SELECT, + WAITER_TYPE_EPOLL, WAITER_TYPE_COUNT, };
@@ -55,5 +56,6 @@ struct waiter_data {
extern const struct waiter_data waiter_poll; extern const struct waiter_data waiter_select; +extern const struct waiter_data waiter_epoll;
#endif