[LTP] [PATCH v2 1/3] syscalls: new test writev07
Jan Stancek
jstancek@redhat.com
Fri Oct 7 10:11:10 CEST 2016
Verify writev() behaviour with partially valid iovec list.
Kernel <4.8 used to shorten write up to first bad invalid
iovec. Starting with 4.8, a writev with short data (under
page size) is likely to get shorten to 0 bytes and return
EFAULT.
This test doesn't make assumptions how much will write get
shortened. It only tests that file content/offset after
syscall corresponds to return value of writev().
See: [RFC] writev() semantics with invalid iovec in the middle
https://marc.info/?l=linux-kernel&m=147388891614289&w=2
This test is meant to be replacement for writev03/writev04
and part of writev01, which all deal with partially invalid
iovec lists, and all currently fail with 4.8 kernel.
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
Changes in v2:
- use tst_res_hexd
- smaller iovec with less random offsets and sizes
- fix tid
runtest/ltplite | 1 +
runtest/stress.part3 | 1 +
runtest/syscalls | 1 +
testcases/kernel/syscalls/.gitignore | 1 +
testcases/kernel/syscalls/writev/writev07.c | 152 ++++++++++++++++++++++++++++
5 files changed, 156 insertions(+)
create mode 100644 testcases/kernel/syscalls/writev/writev07.c
diff --git a/runtest/ltplite b/runtest/ltplite
index 42d9a039ad34..1b4c5f6ee279 100644
--- a/runtest/ltplite
+++ b/runtest/ltplite
@@ -1047,6 +1047,7 @@ writev03 writev03
writev04 writev04
writev05 writev05
writev06 writev06
+writev07 writev07
#DESCRIPTION:Memory Mgmt tests
mm01 mmap001 -m 10000
diff --git a/runtest/stress.part3 b/runtest/stress.part3
index fa75b5c08526..effa5fd9b14e 100644
--- a/runtest/stress.part3
+++ b/runtest/stress.part3
@@ -908,6 +908,7 @@ writev03 writev03
writev04 writev04
writev05 writev05
writev06 writev06
+writev07 writev07
pty01 pty01
hangup01 hangup01
diff --git a/runtest/syscalls b/runtest/syscalls
index 01839e83bf83..88f75971cb3d 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1426,6 +1426,7 @@ writev03 writev03
writev04 writev04
writev05 writev05
writev06 writev06
+writev07 writev07
perf_event_open01 perf_event_open01
perf_event_open02 perf_event_open02
diff --git a/testcases/kernel/syscalls/.gitignore b/testcases/kernel/syscalls/.gitignore
index a13dbb3c5a99..f2aeab45e5bb 100644
--- a/testcases/kernel/syscalls/.gitignore
+++ b/testcases/kernel/syscalls/.gitignore
@@ -1104,6 +1104,7 @@
/writev/writev04
/writev/writev05
/writev/writev06
+/writev/writev07
/fanotify/fanotify01
/fanotify/fanotify02
/fanotify/fanotify03
diff --git a/testcases/kernel/syscalls/writev/writev07.c b/testcases/kernel/syscalls/writev/writev07.c
new file mode 100644
index 000000000000..69471d204811
--- /dev/null
+++ b/testcases/kernel/syscalls/writev/writev07.c
@@ -0,0 +1,152 @@
+/*
+ *
+ * Copyright (c) Linux Test Project, 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ */
+
+/*
+ * Test Description:
+ * Verify writev() behaviour with partially valid iovec list.
+ * Kernel <4.8 used to shorten write up to first bad invalid
+ * iovec. Starting with 4.8, a writev with short data (under
+ * page size) is likely to get shorten to 0 bytes and return
+ * EFAULT.
+ *
+ * This test doesn't make assumptions how much will write get
+ * shortened. It only tests that file content/offset after
+ * syscall corresponds to return value of writev().
+ *
+ * See: [RFC] writev() semantics with invalid iovec in the middle
+ * https://marc.info/?l=linux-kernel&m=147388891614289&w=2
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include "tst_test.h"
+
+#define TESTFILE "testfile"
+#define CHUNK 64
+#define BUFSIZE (CHUNK * 4)
+
+static void *bad_addr;
+
+static void test_partially_valid_iovec(int initial_file_offset)
+{
+ int i, fd;
+ unsigned char buffer[BUFSIZE], fpattern[BUFSIZE], tmp[BUFSIZE];
+ long off_after;
+ struct iovec wr_iovec[] = {
+ { buffer, CHUNK },
+ { bad_addr, CHUNK },
+ { buffer + CHUNK, CHUNK },
+ { buffer + CHUNK * 2, CHUNK },
+ };
+
+ tst_res(TINFO, "starting test with initial file offset: %d ",
+ initial_file_offset);
+
+ for (i = 0; i < BUFSIZE; i++)
+ buffer[i] = i % (CHUNK - 1);
+
+ memset(fpattern, 0xff, BUFSIZE);
+ tst_fill_file(TESTFILE, 0xff, CHUNK, BUFSIZE / CHUNK);
+
+ fd = SAFE_OPEN(TESTFILE, O_RDWR, 0644);
+ SAFE_LSEEK(fd, initial_file_offset, SEEK_SET);
+ TEST(writev(fd, wr_iovec, ARRAY_SIZE(wr_iovec)));
+ off_after = (long) SAFE_LSEEK(fd, 0, SEEK_CUR);
+
+ /* bad errno */
+ if (TEST_RETURN == -1 && TEST_ERRNO != EFAULT) {
+ tst_res(TFAIL | TTERRNO, "unexpected errno");
+ SAFE_CLOSE(fd);
+ return;
+ }
+
+ /* nothing has been written */
+ if (TEST_RETURN == -1 && TEST_ERRNO == EFAULT) {
+ tst_res(TINFO, "got EFAULT");
+ /* initial file content remains untouched */
+ SAFE_LSEEK(fd, 0, SEEK_SET);
+ SAFE_READ(1, fd, tmp, BUFSIZE);
+ if (memcmp(tmp, fpattern, BUFSIZE))
+ tst_res(TFAIL, "file was written to");
+ else
+ tst_res(TPASS, "file stayed untouched");
+
+ /* offset hasn't changed */
+ if (off_after == initial_file_offset)
+ tst_res(TPASS, "offset stayed unchanged");
+ else
+ tst_res(TFAIL, "offset changed to %ld",
+ off_after);
+
+ SAFE_CLOSE(fd);
+ return;
+ }
+
+ /* writev() wrote more bytes than bytes preceding invalid iovec */
+ tst_res(TINFO, "writev() has written %ld bytes", TEST_RETURN);
+ if (TEST_RETURN > (long) wr_iovec[0].iov_base) {
+ tst_res(TFAIL, "writev wrote more than expected");
+ SAFE_CLOSE(fd);
+ return;
+ }
+
+ /* file content matches written bytes */
+ SAFE_LSEEK(fd, initial_file_offset, SEEK_SET);
+ SAFE_READ(1, fd, tmp, TEST_RETURN);
+ if (memcmp(tmp, wr_iovec[0].iov_base, TEST_RETURN) == 0) {
+ tst_res(TPASS, "file has expected content");
+ } else {
+ tst_res(TFAIL, "file has unexpected content");
+ tst_res(TINFO, "expected:");
+ tst_res_hexd(TPASS, wr_iovec[0].iov_base, TEST_RETURN,
+ "expected:");
+ tst_res_hexd(TPASS, tmp, TEST_RETURN,
+ "actual file content:");
+ }
+
+ /* file offset has been updated according to written bytes */
+ if (off_after == initial_file_offset + TEST_RETURN)
+ tst_res(TPASS, "offset at %ld as expected", off_after);
+ else
+ tst_res(TFAIL, "offset unexpected %ld", off_after);
+
+ SAFE_CLOSE(fd);
+}
+
+static void test_writev(void)
+{
+ test_partially_valid_iovec(0);
+ test_partially_valid_iovec(CHUNK + 1);
+ test_partially_valid_iovec(getpagesize());
+ test_partially_valid_iovec(getpagesize() + 1);
+}
+
+static void setup(void)
+{
+ bad_addr = SAFE_MMAP(0, 1, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS,
+ 0, 0);
+}
+
+static struct tst_test test = {
+ .tid = "writev07",
+ .needs_tmpdir = 1,
+ .setup = setup,
+ .test_all = test_writev,
+};
--
1.8.3.1
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