Fix and enhance decoding of sched_[gs]etaffinity syscalls

Print cpu_set_t as a set of integers, similar to the way
fd_set is printed as a set of descriptors.

* affinity.c: Include <sched.h>.
(get_cpuset_size): New function.
(print_affinitylist): Rewrite using get_cpuset_size and next_set_bit.
(sched_getaffinity, sched_setaffinity): Print first two args as ints.
* NEWS: Mention this enhancement.
* tests/sched_xetaffinity.c: New file.
* tests/sched_xetaffinity.test: New test.
* tests/Makefile.am (check_PROGRAMS): Add sched_xetaffinity.
(TESTS): Add sched_xetaffinity.test.
* tests/.gitignore: Add sched_xetaffinity.

Reported-by: Joe Korty <[email protected]>

Author: ldv-alt

NEWS

@@ -2,7 +2,8 @@ Noteworthy changes in release ?.?? (????-??-??)
 ===============================================
 
 * Improvements
-  * Enhanced decoding of personality syscall.
+  * Enhanced decoding of personality, sched_getaffinity,
+    and sched_setaffinity syscalls.
 
 * Bug fixes
   * Fixed build on arc, metag, nios2, or1k, and tile architectures.

affinity.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2002-2004 Roland McGrath <[email protected]>
- * Copyright (c) 2009-2015 Dmitry V. Levin <[email protected]>
+ * Copyright (c) 2009-2016 Dmitry V. Levin <[email protected]>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -27,56 +27,82 @@
  */
 
 #include "defs.h"
+#include <sched.h>
+
+static unsigned int
+get_cpuset_size(void)
+{
+	static unsigned int cpuset_size;
+
+	if (!cpuset_size) {
+		pid_t pid = getpid();
+		cpuset_size = 128;
+		while (cpuset_size &&
+		       sched_getaffinity(pid, cpuset_size, NULL) == -1 &&
+		       EINVAL == errno) {
+			cpuset_size <<= 1;
+		}
+		if (!cpuset_size)
+			cpuset_size = 128;
+	}
+
+	return cpuset_size;
+}
 
 static void
 print_affinitylist(struct tcb *tcp, const unsigned long addr, const unsigned int len)
 {
-	unsigned long w;
-	const unsigned int size = len * sizeof(w);
-	const unsigned long end = addr + size;
-	unsigned long cur, abbrev_end;
+	const unsigned int max_size = get_cpuset_size();
+	const unsigned int umove_size = len < max_size ? len : max_size;
+	const unsigned int size =
+		(umove_size + current_wordsize - 1) & -current_wordsize;
+	const unsigned int ncpu = size * 8;
+	void *cpu;
 
 	if (!verbose(tcp) || (exiting(tcp) && syserror(tcp)) ||
-	    !addr || !len || size / sizeof(w) != len || end < addr) {
+	    !addr || !len || !(cpu = calloc(size, 1))) {
 		printaddr(addr);
 		return;
 	}
 
-	if (abbrev(tcp)) {
-		abbrev_end = addr + max_strlen *  sizeof(w);
-		if (abbrev_end < addr)
-			abbrev_end = end;
-	} else {
-		abbrev_end = end;
-	}
+	if (!umoven_or_printaddr(tcp, addr, umove_size, cpu)) {
+		int i = 0;
+		const char *sep = "";
 
-	tprints("[");
-	for (cur = addr; cur < end; cur += sizeof(w)) {
-		if (cur > addr)
-			tprints(", ");
-		if (cur >= abbrev_end) {
-			tprints("...");
-			break;
+		tprints("[");
+		for (;; i++) {
+			i = next_set_bit(cpu, i, ncpu);
+			if (i < 0)
+				break;
+			tprintf("%s%d", sep, i);
+			sep = " ";
 		}
-		if (umove_or_printaddr(tcp, cur, &w))
-			break;
-		tprintf("%lx", w);
+		if (size < len)
+			tprintf("%s...", sep);
+		tprints("]");
 	}
-	tprints("]");
+
+	free(cpu);
 }
 
 SYS_FUNC(sched_setaffinity)
 {
-	tprintf("%ld, %lu, ", tcp->u_arg[0], tcp->u_arg[1]);
-	print_affinitylist(tcp, tcp->u_arg[2], tcp->u_arg[1]);
+	const int pid = tcp->u_arg[0];
+	const unsigned int len = tcp->u_arg[1];
+
+	tprintf("%d, %u, ", pid, len);
+	print_affinitylist(tcp, tcp->u_arg[2], len);
 
 	return RVAL_DECODED;
 }
 
 SYS_FUNC(sched_getaffinity)
 {
+	const int pid = tcp->u_arg[0];
+	const unsigned int len = tcp->u_arg[1];
+
 	if (entering(tcp)) {
-		tprintf("%ld, %lu, ", tcp->u_arg[0], tcp->u_arg[1]);
+		tprintf("%d, %u, ", pid, len);
 	} else {
 		print_affinitylist(tcp, tcp->u_arg[2], tcp->u_rval);
 	}

tests/.gitignore

@@ -68,6 +68,7 @@ readlink
 readlinkat
 restart_syscall
 rt_sigqueueinfo
+sched_xetaffinity
 sched_xetattr
 scm_rights
 seccomp

tests/Makefile.am

@@ -112,6 +112,7 @@ check_PROGRAMS = \
 	readlinkat \
 	restart_syscall \
 	rt_sigqueueinfo \
+	sched_xetaffinity \
 	sched_xetattr \
 	scm_rights \
 	seccomp \
@@ -245,6 +246,7 @@ TESTS = \
 	readlink.test \
 	readlinkat.test \
 	rt_sigqueueinfo.test \
+	sched_xetaffinity.test \
 	sched_xetattr.test \
 	scm_rights-fd.test \
 	seccomp.test \

tests/sched_xetaffinity.c

@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2016 Dmitry V. Levin <[email protected]>
+ * 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 "tests.h"
+#include <sys/syscall.h>
+#include <sched.h>
+
+#if defined __NR_sched_getaffinity && defined __NR_sched_setaffinity \
+ && defined CPU_ISSET_S && defined CPU_ZERO_S && defined CPU_SET_S
+
+# include <assert.h>
+# include <errno.h>
+# include <stdio.h>
+# include <unistd.h>
+
+static int
+getaffinity(unsigned long pid, unsigned long size, void *set)
+{
+	return syscall(__NR_sched_getaffinity, pid, size, set);
+}
+
+static int
+setaffinity(unsigned long pid, unsigned long size, void *set)
+{
+	return syscall(__NR_sched_setaffinity, pid, size, set);
+}
+
+int
+main(void)
+{
+	unsigned int cpuset_size = 1;
+	pid_t pid = getpid();
+
+	while (cpuset_size) {
+		assert(getaffinity(pid, cpuset_size, NULL) == -1);
+		if (EFAULT == errno)
+			break;
+		if (EINVAL != errno)
+			perror_msg_and_skip("sched_getaffinity");
+		printf("sched_getaffinity(%d, %u, NULL) = -1 EINVAL (%m)\n",
+		       pid, cpuset_size);
+		cpuset_size <<= 1;
+	}
+	assert(cpuset_size);
+	printf("sched_getaffinity(%d, %u, NULL) = -1 EFAULT (%m)\n",
+	       pid, cpuset_size);
+
+	cpu_set_t *cpuset = tail_alloc(cpuset_size);
+	assert(getaffinity(pid, cpuset_size, cpuset) == (int) cpuset_size);
+	printf("sched_getaffinity(%d, %u, [", pid, cpuset_size);
+	const char *sep;
+	unsigned int i, cpu;
+	for (i = 0, cpu = 0, sep = ""; i < cpuset_size * 8; ++i) {
+		if (CPU_ISSET_S(i, cpuset_size, cpuset)) {
+			printf("%s%u", sep, i);
+			sep = " ";
+			cpu = i;
+		}
+	}
+	printf("]) = %u\n", cpuset_size);
+
+	CPU_ZERO_S(cpuset_size, cpuset);
+	CPU_SET_S(cpu, cpuset_size, cpuset);
+	if (setaffinity(pid, cpuset_size, cpuset))
+		perror_msg_and_skip("sched_setaffinity");
+	printf("sched_setaffinity(%d, %u, [%u]) = 0\n",
+	       pid, cpuset_size, cpu);
+
+	const unsigned int big_size = cpuset_size < 128 ? 128 : cpuset_size * 2;
+	cpuset = tail_alloc(big_size);
+	const int ret_size = getaffinity(pid, big_size, cpuset);
+	assert(ret_size >= (int) cpuset_size && ret_size <= (int) big_size);
+	printf("sched_getaffinity(%d, %u, [", pid, big_size);
+	for (i = 0, sep = ""; i < (unsigned) ret_size * 8; ++i) {
+		if (CPU_ISSET_S(i, (unsigned) ret_size, cpuset)) {
+			printf("%s%u", sep, i);
+			sep = " ";
+		}
+	}
+	printf("]) = %d\n", ret_size);
+
+	puts("+++ exited with 0 +++");
+	return 0;
+}
+
+#else
+
+SKIP_MAIN_UNDEFINED("__NR_sched_getaffinity && __NR_sched_setaffinity"
+		    " && CPU_ISSET_S && CPU_ZERO_S && CPU_SET_S")
+
+#endif

tests/sched_xetaffinity.test

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+# Check sched_getaffinity and sched_setaffinity syscalls decoding.
+
+. "${srcdir=.}/init.sh"
+
+run_prog > /dev/null
+OUT="$LOG.out"
+run_strace -a28 -esched_getaffinity,sched_setaffinity $args > "$OUT"
+match_diff "$LOG" "$OUT"
+rm -f "$OUT"
+
+exit 0