Implement decoding of io_uring_* syscalls

... introduced by Linux kernel commits v5.1-rc1~99^2~14,
v5.1-rc1~99^2~7, and v5.1-rc7~24^2.

* configure.ac (AC_CHECK_HEADERS): Add linux/io_uring.h.
* io_uring.c: New file.
* Makefile.am (strace_SOURCES): Add it.
* pathtrace.c (pathtrace_match_set): Add SEN_io_uring_enter,
SEN_io_uring_register, and SEN_io_uring_setup.
* xlat/uring_enter_flags.in: New file.
* xlat/uring_register_opcodes.in: Likewise.
* linux/32/syscallent.h [425, 426, 427]: Wire up io_uring_setup,
io_uring_enter, and io_uring_register.
* linux/64/syscallent.h: Likewise.
* linux/arm/syscallent.h: Likewise.
* linux/hppa/syscallent.h: Likewise.
* linux/i386/syscallent.h: Likewise.
* linux/m68k/syscallent.h: Likewise.
* linux/microblaze/syscallent.h: Likewise.
* linux/powerpc/syscallent.h: Likewise.
* linux/powerpc64/syscallent.h: Likewise.
* linux/s390/syscallent.h: Likewise.
* linux/s390x/syscallent.h: Likewise.
* linux/sh/syscallent.h: Likewise.
* linux/sh64/syscallent.h: Likewise.
* linux/sparc/syscallent.h: Likewise.
* linux/sparc64/syscallent.h: Likewise.
* linux/x32/syscallent.h: Likewise.
* linux/x86_64/syscallent.h: Likewise.
* linux/xtensa/syscallent.h: Likewise.
* linux/alpha/syscallent.h [535, 536, 537]: Likewise.
* linux/ia64/syscallent.h [1024 + 425, 1024 + 426, 1024 + 427]: Likewise.
* linux/mips/syscallent-n32.h [6425, 6426, 6427]: Likewise.
* linux/mips/syscallent-n64.h [5425, 5426, 5427]: Likewise.
* linux/mips/syscallent-o32.h [4425, 4426, 4427]: Likewise.
* NEWS: Mention this change.
* tests/io_uring_enter.c: New file.
* tests/io_uring_register.c: Likewise.
* tests/io_uring_setup.c: Likewise.
* tests/gen_tests.in (io_uring_enter, io_uring_register,
io_uring_setup): New entries.
* tests/pure_executables.list: Add io_uring_enter, io_uring_register,
and io_uring_setup.
* tests/.gitignore: Likewise.

1 files changed, 135 insertions, 0 deletions

diff --git a/io_uring.c b/io_uring.c
new file mode 100644
index 000000000..0b82a0754
--- /dev/null
+++ b/io_uring.c
@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2019 Dmitry V. Levin <ldv@altlinux.org>
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include "defs.h"
+
+#ifdef HAVE_LINUX_IO_URING_H
+# include "print_fields.h"
+# include <linux/io_uring.h>
+#endif
+
+#include "xlat/uring_setup_flags.h"
+#include "xlat/uring_enter_flags.h"
+#include "xlat/uring_register_opcodes.h"
+
+SYS_FUNC(io_uring_setup)
+{
+	const uint32_t nentries = tcp->u_arg[0];
+	const kernel_ulong_t params_addr = tcp->u_arg[1];
+
+#ifdef HAVE_LINUX_IO_URING_H
+	struct io_uring_params params;
+
+	if (entering(tcp)) {
+		tprintf("%u, ", nentries);
+
+		if (umove_or_printaddr(tcp, params_addr, &params))
+			return RVAL_DECODED | RVAL_FD;
+
+		PRINT_FIELD_FLAGS("{", params, flags, uring_setup_flags,
+				  "IORING_SETUP_???");
+		PRINT_FIELD_X(", ", params, sq_thread_cpu);
+		PRINT_FIELD_U(", ", params, sq_thread_idle);
+		for (unsigned int i = 0; i < ARRAY_SIZE(params.resv); ++i) {
+			if (params.resv[i]) {
+				for (i = 0; i < ARRAY_SIZE(params.resv); ++i)
+					tprintf("%s%#x",
+						(i ? ", " : ", resv={"),
+						params.resv[i]);
+				tprints("}");
+				break;
+			}
+		}
+		return 0;
+	} else {
+		if (syserror(tcp)) {
+			/* The remaining part of params is irrelevant.  */
+		} else if (umove(tcp, params_addr, &params)) {
+			tprints(", ???");
+		} else {
+			PRINT_FIELD_U(", ", params, sq_entries);
+			PRINT_FIELD_U(", ", params, cq_entries);
+			PRINT_FIELD_U(", sq_off={", params.sq_off, head);
+			PRINT_FIELD_U(", ", params.sq_off, tail);
+			PRINT_FIELD_U(", ", params.sq_off, ring_mask);
+			PRINT_FIELD_U(", ", params.sq_off, ring_entries);
+			PRINT_FIELD_U(", ", params.sq_off, flags);
+			PRINT_FIELD_U(", ", params.sq_off, dropped);
+			PRINT_FIELD_U(", ", params.sq_off, array);
+			PRINT_FIELD_U("}, cq_off={", params.cq_off, head);
+			PRINT_FIELD_U(", ", params.cq_off, tail);
+			PRINT_FIELD_U(", ", params.cq_off, ring_mask);
+			PRINT_FIELD_U(", ", params.cq_off, ring_entries);
+			PRINT_FIELD_U(", ", params.cq_off, overflow);
+			PRINT_FIELD_U(", ", params.cq_off, cqes);
+			tprints("}");
+		}
+		tprints("}");
+	}
+#else /* !HAVE_LINUX_IO_URING_H */
+	tprintf("%u, ", nentries);
+	printaddr(params_addr);
+#endif
+
+	return RVAL_DECODED | RVAL_FD;
+}
+
+SYS_FUNC(io_uring_enter)
+{
+	const int fd = tcp->u_arg[0];
+	const uint32_t to_submit = tcp->u_arg[1];
+	const uint32_t min_complete = tcp->u_arg[2];
+	const uint32_t flags = tcp->u_arg[3];
+	const kernel_ulong_t sigset_addr = tcp->u_arg[4];
+	const kernel_ulong_t sigset_size = tcp->u_arg[5];
+
+	printfd(tcp, fd);
+	tprintf(", %u, %u, ", to_submit, min_complete);
+	printflags(uring_enter_flags, flags, "IORING_ENTER_???");
+	tprints(", ");
+	print_sigset_addr_len(tcp, sigset_addr, sigset_size);
+	tprintf(", %" PRI_klu, sigset_size);
+
+	return RVAL_DECODED;
+}
+
+static bool
+print_fd_array_member(struct tcb *tcp, void *elem_buf, size_t elem_size,
+		      void *data)
+{
+	printfd(tcp, *(int *) elem_buf);
+	return true;
+}
+
+SYS_FUNC(io_uring_register)
+{
+	const int fd = tcp->u_arg[0];
+	const unsigned int opcode = tcp->u_arg[1];
+	const kernel_ulong_t arg = tcp->u_arg[2];
+	const unsigned int nargs = tcp->u_arg[3];
+	int buf;
+
+	printfd(tcp, fd);
+	tprints(", ");
+	printxval(uring_register_opcodes, opcode, "IORING_REGISTER_???");
+	tprints(", ");
+	switch (opcode) {
+		case IORING_REGISTER_BUFFERS:
+			tprint_iov(tcp, nargs, arg, IOV_DECODE_ADDR);
+			break;
+		case IORING_REGISTER_FILES:
+			print_array(tcp, arg, nargs, &buf, sizeof(buf),
+				    tfetch_mem, print_fd_array_member, NULL);
+			break;
+		default:
+			printaddr(arg);
+			break;
+	}
+	tprintf(", %u", nargs);
+
+	return RVAL_DECODED;
+}