Add symlinkat test case

Tests successful creation (using readlink() to verify the contents),
EEXIST, ENOENT cases.

Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
Link: https://lore.kernel.org/r/20210603052906.2616489-6-dkadashev@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

3 files changed, 116 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index a9ae5bb..0b336d6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -112,6 +112,7 @@
 /test/statx
 /test/stdout
 /test/submit-reuse
+/test/symlink
 /test/teardowns
 /test/thread-exit
 /test/timeout
diff --git a/test/Makefile b/test/Makefile
index 86437d5..4fc78ea 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -108,6 +108,7 @@ test_targets += \
 	sq-space_left \
 	stdout \
 	submit-reuse \
+	symlink \
 	teardowns \
 	thread-exit \
 	timeout \
@@ -248,6 +249,7 @@ test_srcs := \
 	statx.c \
 	stdout.c \
 	submit-reuse.c \
+	symlink.c \
 	teardowns.c \
 	thread-exit.c \
 	timeout-new.c \
diff --git a/test/symlink.c b/test/symlink.c
new file mode 100644
index 0000000..8b5e04a
--- /dev/null
+++ b/test/symlink.c
@@ -0,0 +1,113 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test io_uring symlinkat handling
+ */
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "liburing.h"
+
+
+static int do_symlinkat(struct io_uring *ring, const char *oldname, const char *newname)
+{
+	int ret;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "sqe get failed\n");
+		goto err;
+	}
+	io_uring_prep_symlinkat(sqe, oldname, AT_FDCWD, newname);
+
+	ret = io_uring_submit(ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit failed: %d\n", ret);
+		goto err;
+	}
+
+	ret = io_uring_wait_cqes(ring, &cqe, 1, 0, 0);
+	if (ret) {
+		fprintf(stderr, "wait_cqe failed: %d\n", ret);
+		goto err;
+	}
+	ret = cqe->res;
+	io_uring_cqe_seen(ring, cqe);
+	return ret;
+err:
+	return 1;
+}
+
+int test_link_contents(const char* linkname, const char *expected_contents)
+{
+	char buf[128];
+	int ret = readlink(linkname, buf, 127);
+	if (ret < 0) {
+		perror("readlink");
+		return ret;
+	}
+	buf[ret] = 0;
+	if (strncmp(buf, expected_contents, 128)) {
+		fprintf(stderr, "link contents differs from expected: '%s' vs '%s'",
+			buf, expected_contents);
+		return -1;
+	}
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	static const char target[] = "io_uring-symlinkat-test-target";
+	static const char linkname[] = "io_uring-symlinkat-test-link";
+	int ret;
+	struct io_uring ring;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "queue init failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = do_symlinkat(&ring, target, linkname);
+	if (ret < 0) {
+		if (ret == -EBADF || ret == -EINVAL) {
+			fprintf(stdout, "symlinkat not supported, skipping\n");
+			goto out;
+		}
+		fprintf(stderr, "symlinkat: %s\n", strerror(-ret));
+		goto err;
+	} else if (ret) {
+		goto err;
+	}
+
+	ret = test_link_contents(linkname, target);
+	if (ret < 0)
+		goto err1;
+
+	ret = do_symlinkat(&ring, target, linkname);
+	if (ret != -EEXIST) {
+		fprintf(stderr, "test_symlinkat linkname already exists failed: %d\n", ret);
+		goto err1;
+	}
+
+	ret = do_symlinkat(&ring, target, "surely/this/does/not/exist");
+	if (ret != -ENOENT) {
+		fprintf(stderr, "test_symlinkat no parent failed: %d\n", ret);
+		goto err1;
+	}
+
+out:
+	unlinkat(AT_FDCWD, linkname, 0);
+	io_uring_queue_exit(&ring);
+	return 0;
+err1:
+	unlinkat(AT_FDCWD, linkname, 0);
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}