Merge branch 'master' of https://github.com/CarterLi/liburing

* 'master' of https://github.com/CarterLi/liburing:
  examples/ucontext-cp: use ucontext with liburing

1 files changed, 188 insertions, 0 deletions

diff --git a/examples/ucontext-cp.c b/examples/ucontext-cp.c
new file mode 100644
index 0000000..1f76a09
--- /dev/null
+++ b/examples/ucontext-cp.c
@@ -0,0 +1,188 @@
+/*
+ * gcc -Wall -O2 -D_GNU_SOURCE -o ucontext-cp ucontext-cp.c -luring
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <ucontext.h>
+#include <signal.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include "liburing.h"
+
+#define QD	64
+#define BS	(32*1024)
+
+typedef struct {
+	struct io_uring ring;
+	unsigned char stack_buf[SIGSTKSZ];
+	ucontext_t ctx_main, ctx_fnew;
+} async_context;
+
+typedef struct {
+	async_context *pctx;
+	int ret;
+	int infd;
+	int outfd;
+} arguments_bundle;
+
+#define DEFINE_AWAIT_OP(operation) \
+static ssize_t await_##operation( \
+	async_context *pctx, \
+	int fd, \
+	const struct iovec *ioves, \
+	unsigned int nr_vecs, \
+	off_t offset) \
+{ \
+	struct io_uring_sqe *sqe = io_uring_get_sqe(&pctx->ring); \
+\
+	if (!sqe) { \
+		return -1; \
+	} \
+\
+	io_uring_prep_##operation(sqe, fd, ioves, nr_vecs, offset); \
+	io_uring_sqe_set_data(sqe, pctx); \
+	io_uring_submit(&pctx->ring); \
+	swapcontext(&pctx->ctx_fnew, &pctx->ctx_main); \
+	struct io_uring_cqe *cqe; \
+	if (io_uring_peek_cqe(&pctx->ring, &cqe) < 0) { \
+		return -1; \
+	} \
+	io_uring_cqe_seen(&pctx->ring, cqe); \
+\
+	return cqe->res; \
+}
+
+DEFINE_AWAIT_OP(readv)
+DEFINE_AWAIT_OP(writev)
+#undef DEFINE_AWAIT_OP
+
+static int setup_context(unsigned entries, async_context *pctx)
+{
+	int ret;
+
+	ret = io_uring_queue_init(entries, &pctx->ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+		return -1;
+	}
+
+	ret = getcontext(&pctx->ctx_fnew);
+	if (ret < 0) {
+		perror("getcontext");
+		return -1;
+	}
+	pctx->ctx_fnew.uc_stack.ss_sp = &pctx->stack_buf;
+	pctx->ctx_fnew.uc_stack.ss_size = sizeof(pctx->stack_buf);
+	pctx->ctx_fnew.uc_link = &pctx->ctx_main;
+
+	return 0;
+}
+
+static int copy_file(async_context *pctx, int infd, int outfd, struct iovec* piov)
+{
+	off_t offset = 0;
+
+	for (;;) {
+		ssize_t bytes_read;
+
+		if ((bytes_read = await_readv(pctx, infd, piov, 1, offset)) < 0) {
+			perror("await_readv");
+			return 1;
+		}
+		if (bytes_read == 0) return 0;
+		piov->iov_len = bytes_read;
+
+		if (await_writev(pctx, outfd, piov, 1, offset) != bytes_read) {
+			perror("await_writev");
+			return 1;
+		}
+		if (bytes_read < BS) return 0;
+		offset += bytes_read;
+	}
+}
+
+static void copy_file_wrapper(arguments_bundle *pbundle) {
+	struct iovec iov = {
+		.iov_base = malloc(BS),
+		.iov_len = BS,
+	};
+	async_context *pctx = pbundle->pctx;
+
+	pbundle->ret = copy_file(pctx, pbundle->infd, pbundle->outfd, &iov);
+
+	free(iov.iov_base);
+	swapcontext(&pctx->ctx_fnew, &pctx->ctx_main);
+}
+
+int main(int argc, char *argv[])
+{
+	async_context ctx;
+	int infd, outfd;
+	struct io_uring_cqe *cqe;
+
+	if (argc < 3) {
+		printf("%s: infile outfile\n", argv[0]);
+		return 1;
+	}
+
+	infd = open(argv[1], O_RDONLY);
+	if (infd < 0) {
+		perror("open infile");
+		return 1;
+	}
+	outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	if (outfd < 0) {
+		perror("open outfile");
+		return 1;
+	}
+
+	if (setup_context(QD, &ctx))
+		return 1;
+
+	arguments_bundle bundle = {
+		.pctx = &ctx,
+		.ret = -1,
+		.infd = infd,
+		.outfd = outfd,
+	};
+
+	makecontext(&ctx.ctx_fnew, (void (*)(void)) copy_file_wrapper, 1, &bundle);
+
+	if (swapcontext(&ctx.ctx_main, &ctx.ctx_fnew)) {
+		perror("swapcontext");
+		return 1;
+	}
+
+	// event loop
+	while (bundle.ret == -1) {
+		int ret;
+		async_context* pctx;
+
+		// usually be timed waiting
+		ret = io_uring_wait_cqe(&ctx.ring, &cqe);
+		if (ret < 0) {
+			fprintf(stderr, "wait_cqe: %s\n", strerror(-ret));
+			return 1;
+		}
+
+		pctx = io_uring_cqe_get_data(cqe);
+		assert(pctx == &ctx);
+
+		if (swapcontext(&pctx->ctx_main, &pctx->ctx_fnew)) {
+			perror("swapcontext");
+			return 1;
+		}
+	}
+
+	close(outfd);
+	close(infd);
+	io_uring_queue_exit(&ctx.ring);
+
+	return 0;
+}