Fix testing with read-only source directory

Fix testing with read-only source directory

[Joseph Myers]

Three tests fail with a read-only source directory because they try to
write into the source directory.  None of these write into it in a way
that should actually be problematic for concurrent builds sharing the
same writable source directory, but avoiding any writing into the
source directory (from testing, or from building glibc if the source
timestamps are properly ordered) is still a good idea, as being able
to build with read-only sources helps make sure there isn't anything
that could cause problems for concurrent builds.

This patch changes the tests in question to use either /tmp or the
build directory to write their temporary files (or to test O_TMPFILE,
as applicable).

Tested for x86_64.

2017-12-15  Joseph Myers  <joseph@codesourcery.com>

	* io/Makefile (tst-open-tmpfile-ARGS): New variable.
	* posix/tst-mmap-offset.c (fname): Use /tmp.
	* stdlib/tst-setcontext3.sh (tempfile): Use ${objpfx}.

diff --git a/io/Makefile b/io/Makefile
index b3ee5ae..c725195 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -109,6 +109,8 @@ test-stat2-ARGS = Makefile . $(objpfx)test-stat2
 
 tst-statvfs-ARGS = $(objpfx)tst-statvfs tst-statvfs.c /tmp
 
+tst-open-tmpfile-ARGS = --test-dir=$(objpfx)
+
 ifeq ($(run-built-tests),yes)
 $(objpfx)ftwtest.out: ftwtest-sh $(objpfx)ftwtest
 	$(SHELL) $< $(common-objpfx) '$(test-program-cmd)' > $@; \
diff --git a/posix/tst-mmap-offset.c b/posix/tst-mmap-offset.c
index 5bb88aa..5e940c8 100644
--- a/posix/tst-mmap-offset.c
+++ b/posix/tst-mmap-offset.c
@@ -29,7 +29,7 @@
 
 static int fd;
 static long int page_shift;
-static char fname[] = "tst-mmap-offset-XXXXXX";
+static char fname[] = "/tmp/tst-mmap-offset-XXXXXX";
 
 static void
 do_prepare (int argc, char **argv)
diff --git a/stdlib/tst-setcontext3.sh b/stdlib/tst-setcontext3.sh
index 158d0dc..014e7cf 100644
--- a/stdlib/tst-setcontext3.sh
+++ b/stdlib/tst-setcontext3.sh
@@ -34,7 +34,7 @@ cleanup() {
 }
 trap cleanup 0
 
-tempfile=$(mktemp "tst-setcontext3.XXXXXXXXXX")
+tempfile=$(mktemp "${objpfx}tst-setcontext3.XXXXXXXXXX")
 
 # We want to run the test program and see if secontext called
 # exit() and wrote out the test file we specified.  If the

-- 
Joseph S. Myers
joseph@codesourcery.com

Re: Fix testing with read-only source directory

[Jonathan Nieder]

Joseph Myers wrote:

> Three tests fail with a read-only source directory because they try to
> write into the source directory.  None of these write into it in a way
> that should actually be problematic for concurrent builds sharing the
> same writable source directory, but avoiding any writing into the
> source directory (from testing, or from building glibc if the source
> timestamps are properly ordered) is still a good idea, as being able
> to build with read-only sources helps make sure there isn't anything
> that could cause problems for concurrent builds.
>
> This patch changes the tests in question to use either /tmp or the
> build directory to write their temporary files (or to test O_TMPFILE,
> as applicable).
>
> Tested for x86_64.
>
> 2017-12-15  Joseph Myers  <joseph@codesourcery.com>
>
> 	* io/Makefile (tst-open-tmpfile-ARGS): New variable.
> 	* posix/tst-mmap-offset.c (fname): Use /tmp.
> 	* stdlib/tst-setcontext3.sh (tempfile): Use ${objpfx}.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Thanks for fixing it.

[...]
> --- a/posix/tst-mmap-offset.c
> +++ b/posix/tst-mmap-offset.c
> @@ -29,7 +29,7 @@
>  
>  static int fd;
>  static long int page_shift;
> -static char fname[] = "tst-mmap-offset-XXXXXX";
> +static char fname[] = "/tmp/tst-mmap-offset-XXXXXX";

It would be nice if this kind of test respected $TMPDIR, but that's an
orthogonal problem --- what this patch does is consistent with the
other tests in this dir.