tests: extend test coverage of setresuid syscall

* tests/setresugid.c: New file.
* tests/setresuid.c: New file.
* tests/setresuid.test: New test.
* tests/.gitignore: Add setresuid.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add setresuid.test.
(EXTRA_DIST): Add setresugid.c.
diff --git a/tests/.gitignore b/tests/.gitignore
index 02ea5b0..8368c0f 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -147,6 +147,7 @@
 sethostname
 setregid
 setregid32
+setresuid
 setreuid
 setreuid32
 setuid
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 95d75a8..ca89c14 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -197,6 +197,7 @@
 	sethostname \
 	setregid \
 	setregid32 \
+	setresuid \
 	setreuid \
 	setreuid32 \
 	setuid \
@@ -412,6 +413,7 @@
 	sethostname.test \
 	setregid.test \
 	setregid32.test \
+	setresuid.test \
 	setreuid.test \
 	setreuid32.test \
 	setuid.test \
@@ -523,6 +525,7 @@
 	     ppoll.expected \
 	     ppoll-v.expected \
 	     setreugid.c \
+	     setresugid.c \
 	     setugid.c \
 	     sigaction.awk \
 	     sigaltstack.expected \
diff --git a/tests/setresugid.c b/tests/setresugid.c
new file mode 100644
index 0000000..711bd31
--- /dev/null
+++ b/tests/setresugid.c
@@ -0,0 +1,113 @@
+/*
+ * Check decoding of setresuid/setresgid/setresuid32/setresgid32 syscalls.
+ *
+ * Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+
+static int
+ugid2int(const unsigned UGID_TYPE ugid)
+{
+	if ((unsigned UGID_TYPE) -1U == ugid)
+		return -1;
+	else
+		return ugid;
+}
+
+static void
+print_int(const unsigned int num)
+{
+	if (num == -1U)
+		printf("-1");
+	else
+		printf("%u", num);
+}
+
+static int
+num_matches_id(const unsigned int num, const unsigned int ugid)
+{
+	return num == ugid || num == -1U;
+}
+
+#define TRIPLE(val)	\
+	{ val, ugid, ugid }, { ugid, val, ugid }, { ugid, ugid, val }
+
+int
+main(void)
+{
+	unsigned int ugid = GETUGID;
+	CHECK_OVERFLOWUGID(ugid);
+
+	const struct {
+		const long r, e, s;
+	} tests[] = {
+		{ ugid, ugid, ugid },
+		TRIPLE((unsigned long) 0xffffffff00000000ULL | ugid),
+		TRIPLE(-1U),
+		TRIPLE(-1L),
+		TRIPLE(0xffff0000U | ugid),
+		TRIPLE(0xffff),
+		TRIPLE(0xc0deffffU)
+	};
+
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(tests); ++i) {
+		const unsigned int rn = ugid2int(tests[i].r);
+		const unsigned int en = ugid2int(tests[i].e);
+		const unsigned int sn = ugid2int(tests[i].s);
+
+		if (!num_matches_id(rn, ugid) ||
+		    !num_matches_id(en, ugid) ||
+		    !num_matches_id(sn, ugid))
+			continue;
+
+		if (syscall(SYSCALL_NR, tests[i].r, tests[i].e, tests[i].s)) {
+			if (!i && ENOSYS == errno) {
+				printf("%s(%u, %u, %u) = -1 ENOSYS (%m)\n",
+				       SYSCALL_NAME, ugid, ugid, ugid);
+				break;
+			}
+			perror_msg_and_fail("%s(%#lx, %#lx, %#lx)",
+					    SYSCALL_NAME,
+					    tests[i].r, tests[i].e, tests[i].s);
+		}
+
+		printf("%s(", SYSCALL_NAME);
+		print_int(rn);
+		printf(", ");
+		print_int(en);
+		printf(", ");
+		print_int(sn);
+		printf(") = 0\n");
+	}
+
+	puts("+++ exited with 0 +++");
+	return 0;
+}
diff --git a/tests/setresuid.c b/tests/setresuid.c
new file mode 100644
index 0000000..b924f91
--- /dev/null
+++ b/tests/setresuid.c
@@ -0,0 +1,25 @@
+#include "tests.h"
+#include <sys/syscall.h>
+
+#ifdef __NR_setresuid
+
+# define SYSCALL_NR	__NR_setresuid
+# define SYSCALL_NAME	"setresuid"
+
+# if defined __NR_setresuid32 && __NR_setresuid != __NR_setresuid32
+#  define UGID_TYPE	short
+#  define GETUGID	syscall(__NR_geteuid)
+#  define CHECK_OVERFLOWUGID(arg)	check_overflowuid(arg)
+# else
+#  define UGID_TYPE	int
+#  define GETUGID	geteuid()
+#  define CHECK_OVERFLOWUGID(arg)
+# endif
+
+# include "setresugid.c"
+
+#else
+
+SKIP_MAIN_UNDEFINED("__NR_setresuid")
+
+#endif
diff --git a/tests/setresuid.test b/tests/setresuid.test
new file mode 100755
index 0000000..f1219e0
--- /dev/null
+++ b/tests/setresuid.test
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# Check setresuid syscall decoding.
+
+. "${srcdir=.}/init.sh"
+run_strace_match_diff -a19