Hi,
On 01/15/2016 11:33 PM, Dmitry V. Levin wrote:
Hi,
On Fri, Jan 15, 2016 at 05:06:13PM +0800, Fei, Jie/费 杰 wrote:
Hi!
I'm still not sure what kind of tests are needed so I continued writing
patches.
Could you give me some advice on these patches?
First of all, there has to be clear what is being tested.
Taking your clone-f.test as an example, are you testing just the fact
of following both threads after clone syscall, or maybe something beyond
that?
Yes, this patch is testing whether strace can trace both threads after
clone syscall.
On 01/13/2016 04:43 PM, Fei Jie wrote:
tests: add clone-f.test.
Check how strace -f follows clone syscall.
* tests/clone-f.c: New file.
* tests/clone-f.test: New test.
* tests/Makefile.am: (check_PROGRAMS): Add clone-f.
(TESTS): Add clone-f.test.
* tests/.gitignore: Add clone-f.
---
tests/.gitignore | 1 +
tests/Makefile.am | 2 ++
tests/clone-f.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
tests/clone-f.test | 11 +++++++++++
4 files changed, 58 insertions(+)
create mode 100644 tests/clone-f.c
create mode 100755 tests/clone-f.test
diff --git a/tests/.gitignore b/tests/.gitignore
index cfe1e9f..7aa2449 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -12,6 +12,7 @@ bpf
caps
clock_nanosleep
clock_xettime
+clone-f
epoll_create1
eventfd
execve
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 33f76cb..80292c4 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -58,6 +58,7 @@ check_PROGRAMS = \
caps \
clock_nanosleep \
clock_xettime \
+ clone-f \
epoll_create1 \
eventfd \
execve \
@@ -194,6 +195,7 @@ TESTS = \
caps.test \
clock_nanosleep.test \
clock_xettime.test \
+ clone-f.test \
dumpio.test \
epoll_create1.test \
eventfd.test \
diff --git a/tests/clone-f.c b/tests/clone-f.c
new file mode 100644
index 0000000..df97b54
--- /dev/null
+++ b/tests/clone-f.c
@@ -0,0 +1,44 @@
+#include "tests.h"
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <signal.h>
+
+#define CHILD_STACK_SIZE 16384
+
+static int
+logit(const char *const str)
+{
+ return pwrite(-1, str, strlen(str), 0) >= 0;
My original idea of using pwrite for text marks in the log haven't passed
the test of real world: I stumbled upon a system where pwrite is not
implemented using pwrite64 syscall. I had to replace pwrite with chdir
which is portable (see commit v4.11-125-g6833d61).
Thanks, I've replaced pwrite with chdir in patch-v2.
+}
+
+void
+child(void)
+{
+ logit("child");
+}
+
+int main()
+{
+ logit("parent");
+
+ void *child_stack;
+ if ((child_stack = (void *) malloc(CHILD_STACK_SIZE)) == NULL) {
+ printf("cannot allocate stack for child!\n");
+ }
+
+ pid_t child_pid = clone(&child, child_stack + CHILD_STACK_SIZE,
CLONE_VM, NULL);
On some architectures supported by strace, stack grows upwards.
clone behavior noticeably depends on the clone flags. Is there any
particular reason to use these flags in the test?
I added some codes to determine which way of clone is used in patch-v2.
+ if (child_pid < 0) {
+ perror_msg_and_fail("clone");
+ }
+
+ free(child_stack);
+
+ pid_t pid = getpid();
+ printf("%-5d pwrite64(-1, \"parent\", 6, 0) = -1 EBADF (%m)\n"
+ "%-5d pwrite64(-1, \"child\", 5, 0) = -1 EBADF (%m)\n",
+ pid, child_pid);
There is no guarantee of the parent being first, or visa versa.
I explicitly added synchronization into fork-f.test and vfork-f.test
to make the output predictable.
Thanks, I set the clone flag SIGCHLD, and let parent do chdir() after
child finished in patch-v2.
+ return 0;
+}
diff --git a/tests/clone-f.test b/tests/clone-f.test
new file mode 100755
index 0000000..439426d
--- /dev/null
+++ b/tests/clone-f.test
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+. "${srcdir=.}/init.sh"
+
+OUT="$LOG.out"
+run_prog > /dev/null
+run_strace -a32 -epwrite64 -esignal=none -f -qq $args >"$OUT"
+match_diff "$LOG" "$OUT"
+rm -f "$OUT"
+
+exit 0
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--
Thanks!
Fei Jie
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