1 files changed, 315 insertions, 0 deletions
diff --git a/src/io.c b/src/io.c
new file mode 100644
index 000000000..db4b667d9
--- /dev/null
+++ b/src/io.c
@@ -0,0 +1,315 @@
+/*
+ * Copyright (c) 1991, 1992 Paul Kranenburg <pk@cs.few.eur.nl>
+ * Copyright (c) 1993 Branko Lankester <branko@hacktic.nl>
+ * Copyright (c) 1993, 1994, 1995, 1996 Rick Sladkey <jrs@world.std.com>
+ * Copyright (c) 1996-1999 Wichert Akkerman <wichert@cistron.nl>
+ * Copyright (c) 1999-2020 The strace developers.
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+#include "defs.h"
+#include <fcntl.h>
+#include <sys/uio.h>
+
+SYS_FUNC(read)
+{
+	if (entering(tcp)) {
+		printfd(tcp, tcp->u_arg[0]);
+		tprints(", ");
+	} else {
+		if (syserror(tcp))
+			printaddr(tcp->u_arg[1]);
+		else
+			printstrn(tcp, tcp->u_arg[1], tcp->u_rval);
+		tprintf(", %" PRI_klu, tcp->u_arg[2]);
+	}
+	return 0;
+}
+
+SYS_FUNC(write)
+{
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	printstrn(tcp, tcp->u_arg[1], tcp->u_arg[2]);
+	tprintf(", %" PRI_klu, tcp->u_arg[2]);
+
+	return RVAL_DECODED;
+}
+
+struct print_iovec_config {
+	enum iov_decode decode_iov;
+	kernel_ulong_t data_size;
+};
+
+static bool
+print_iovec(struct tcb *tcp, void *elem_buf, size_t elem_size, void *data)
+{
+	const kernel_ulong_t *iov;
+	kernel_ulong_t iov_buf[2], len;
+	struct print_iovec_config *c = data;
+
+	if (elem_size < sizeof(iov_buf)) {
+		iov_buf[0] = ((unsigned int *) elem_buf)[0];
+		iov_buf[1] = ((unsigned int *) elem_buf)[1];
+		iov = iov_buf;
+	} else {
+		iov = elem_buf;
+	}
+
+	tprint_struct_begin();
+	tprints_field_name("iov_base");
+
+	len = iov[1];
+
+	switch (c->decode_iov) {
+		case IOV_DECODE_STR:
+			if (len > c->data_size)
+				len = c->data_size;
+			if (c->data_size != (kernel_ulong_t) -1)
+				c->data_size -= len;
+			printstrn(tcp, iov[0], len);
+			break;
+		case IOV_DECODE_NETLINK:
+			if (len > c->data_size)
+				len = c->data_size;
+			if (c->data_size != (kernel_ulong_t) -1)
+				c->data_size -= len;
+			/* assume that the descriptor is 1st syscall argument */
+			decode_netlink(tcp, tcp->u_arg[0], iov[0], len);
+			break;
+		default:
+			printaddr(iov[0]);
+			break;
+	}
+
+	tprint_struct_next();
+	tprints_field_name("iov_len");
+	tprintf("%" PRI_klu, iov[1]);
+	tprint_struct_end();
+
+	return true;
+}
+
+/*
+ * data_size limits the cumulative size of printed data.
+ * Example: recvmsg returning a short read.
+ */
+void
+tprint_iov_upto(struct tcb *const tcp, const kernel_ulong_t len,
+		const kernel_ulong_t addr, const enum iov_decode decode_iov,
+		const kernel_ulong_t data_size)
+{
+	kernel_ulong_t iov[2];
+	struct print_iovec_config config = {
+		.decode_iov = decode_iov, .data_size = data_size
+	};
+
+	print_array(tcp, addr, len, iov, current_wordsize * 2,
+		    tfetch_mem_ignore_syserror, print_iovec, &config);
+}
+
+SYS_FUNC(readv)
+{
+	if (entering(tcp)) {
+		printfd(tcp, tcp->u_arg[0]);
+		tprints(", ");
+	} else {
+		tprint_iov_upto(tcp, tcp->u_arg[2], tcp->u_arg[1],
+				syserror(tcp) ? IOV_DECODE_ADDR :
+				IOV_DECODE_STR, tcp->u_rval);
+		tprintf(", %" PRI_klu, tcp->u_arg[2]);
+	}
+	return 0;
+}
+
+SYS_FUNC(writev)
+{
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	tprint_iov(tcp, tcp->u_arg[2], tcp->u_arg[1], IOV_DECODE_STR);
+	tprintf(", %" PRI_klu, tcp->u_arg[2]);
+
+	return RVAL_DECODED;
+}
+
+SYS_FUNC(pread)
+{
+	if (entering(tcp)) {
+		printfd(tcp, tcp->u_arg[0]);
+		tprints(", ");
+	} else {
+		if (syserror(tcp))
+			printaddr(tcp->u_arg[1]);
+		else
+			printstrn(tcp, tcp->u_arg[1], tcp->u_rval);
+		tprintf(", %" PRI_klu ", ", tcp->u_arg[2]);
+		printllval(tcp, "%lld", 3);
+	}
+	return 0;
+}
+
+SYS_FUNC(pwrite)
+{
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	printstrn(tcp, tcp->u_arg[1], tcp->u_arg[2]);
+	tprintf(", %" PRI_klu ", ", tcp->u_arg[2]);
+	printllval(tcp, "%lld", 3);
+
+	return RVAL_DECODED;
+}
+
+static void
+print_lld_from_low_high_val(struct tcb *tcp, int arg)
+{
+#if SIZEOF_KERNEL_LONG_T > 4
+# ifndef current_klongsize
+	if (current_klongsize < SIZEOF_KERNEL_LONG_T) {
+		tprintf("%" PRI_kld, (tcp->u_arg[arg + 1] << 32)
+			       | tcp->u_arg[arg]);
+	} else
+# endif /* !current_klongsize */
+	{
+		tprintf("%" PRI_kld, tcp->u_arg[arg]);
+	}
+#else /* SIZEOF_KERNEL_LONG_T == 4 */
+	tprintf("%lld",
+		  ((long long) tcp->u_arg[arg + 1] << 32)
+		| ((long long) tcp->u_arg[arg]));
+#endif
+}
+
+#include "xlat/rwf_flags.h"
+
+static int
+do_preadv(struct tcb *tcp, const int flags_arg)
+{
+	if (entering(tcp)) {
+		printfd(tcp, tcp->u_arg[0]);
+		tprints(", ");
+	} else {
+		kernel_ulong_t len =
+			truncate_kulong_to_current_wordsize(tcp->u_arg[2]);
+
+		tprint_iov_upto(tcp, len, tcp->u_arg[1],
+				syserror(tcp) ? IOV_DECODE_ADDR :
+				IOV_DECODE_STR, tcp->u_rval);
+		tprintf(", %" PRI_klu ", ", len);
+		print_lld_from_low_high_val(tcp, 3);
+		if (flags_arg >= 0) {
+			tprints(", ");
+			printflags(rwf_flags, tcp->u_arg[flags_arg], "RWF_???");
+		}
+	}
+	return 0;
+}
+
+SYS_FUNC(preadv)
+{
+	return do_preadv(tcp, -1);
+}
+
+static int
+do_pwritev(struct tcb *tcp, const int flags_arg)
+{
+	kernel_ulong_t len =
+		truncate_kulong_to_current_wordsize(tcp->u_arg[2]);
+
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	tprint_iov(tcp, len, tcp->u_arg[1], IOV_DECODE_STR);
+	tprintf(", %" PRI_klu ", ", len);
+	print_lld_from_low_high_val(tcp, 3);
+	if (flags_arg >= 0) {
+		tprints(", ");
+		printflags(rwf_flags, tcp->u_arg[flags_arg], "RWF_???");
+	}
+
+	return RVAL_DECODED;
+}
+
+SYS_FUNC(pwritev)
+{
+	return do_pwritev(tcp, -1);
+}
+
+/*
+ * x32 is the only architecture where preadv2 takes 5 arguments
+ * instead of 6, see preadv64v2 in kernel sources.
+ * Likewise, x32 is the only architecture where pwritev2 takes 5 arguments
+ * instead of 6, see pwritev64v2 in kernel sources.
+ */
+
+#if defined X86_64
+# define PREADV2_PWRITEV2_FLAGS_ARG_NO (current_personality == 2 ? 4 : 5)
+#elif defined X32
+# define PREADV2_PWRITEV2_FLAGS_ARG_NO (current_personality == 0 ? 4 : 5)
+#else
+# define PREADV2_PWRITEV2_FLAGS_ARG_NO 5
+#endif
+
+SYS_FUNC(preadv2)
+{
+	return do_preadv(tcp, PREADV2_PWRITEV2_FLAGS_ARG_NO);
+}
+
+SYS_FUNC(pwritev2)
+{
+	return do_pwritev(tcp, PREADV2_PWRITEV2_FLAGS_ARG_NO);
+}
+
+#include "xlat/splice_flags.h"
+
+SYS_FUNC(tee)
+{
+	/* int fd_in */
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	/* int fd_out */
+	printfd(tcp, tcp->u_arg[1]);
+	tprints(", ");
+	/* size_t len */
+	tprintf("%" PRI_klu ", ", tcp->u_arg[2]);
+	/* unsigned int flags */
+	printflags(splice_flags, tcp->u_arg[3], "SPLICE_F_???");
+
+	return RVAL_DECODED;
+}
+
+SYS_FUNC(splice)
+{
+	/* int fd_in */
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	/* loff_t *off_in */
+	printnum_int64(tcp, tcp->u_arg[1], "%" PRId64);
+	tprints(", ");
+	/* int fd_out */
+	printfd(tcp, tcp->u_arg[2]);
+	tprints(", ");
+	/* loff_t *off_out */
+	printnum_int64(tcp, tcp->u_arg[3], "%" PRId64);
+	tprints(", ");
+	/* size_t len */
+	tprintf("%" PRI_klu ", ", tcp->u_arg[4]);
+	/* unsigned int flags */
+	printflags(splice_flags, tcp->u_arg[5], "SPLICE_F_???");
+
+	return RVAL_DECODED;
+}
+
+SYS_FUNC(vmsplice)
+{
+	/* int fd */
+	printfd(tcp, tcp->u_arg[0]);
+	tprints(", ");
+	/* const struct iovec *iov, unsigned long nr_segs */
+	tprint_iov(tcp, tcp->u_arg[2], tcp->u_arg[1], IOV_DECODE_STR);
+	tprintf(", %" PRI_klu ", ", tcp->u_arg[2]);
+	/* unsigned int flags */
+	printflags(splice_flags, tcp->u_arg[3], "SPLICE_F_???");
+
+	return RVAL_DECODED;
+}