Re: [Qemu-trivial] [Qemu-devel] [PATCH] tests/boot-sector: Use mkstemp() to create a unique file name

[Greg Kurz <groug@kaod.org>]

On Tue, 11 Oct 2016 16:06:55 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 11.10.2016 15:55, Greg Kurz wrote:
> > On Tue, 11 Oct 2016 15:32:02 +0200
> > Thomas Huth <thuth@redhat.com> wrote:
> >   
> >> The pxe-test is run for three different targets now (x86_64, i386
> >> and ppc64), and the bios-tables-test is run for two targets (x86_64
> >> and i386). But each of the tests is using an invariant name for the
> >> disk image with the boot sector code - so if the tests are running
> >> in parallel, there is a race condition that they destroy the disk
> >> image of a parallel test program. Let's use mkstemp() to create
> >> unique temporary files here instead.
> >>
> >> Reported-by: Sascha Silbe <x-qemu@se-silbe.de>
> >> Signed-off-by: Thomas Huth <thuth@redhat.com>
> >> ---
> >>  tests/bios-tables-test.c | 2 +-
> >>  tests/boot-sector.c      | 9 +++++++--
> >>  tests/boot-sector.h      | 4 ++--
> >>  tests/pxe-test.c         | 2 +-
> >>  4 files changed, 11 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c
> >> index 6ea2b6d..812f830 100644
> >> --- a/tests/bios-tables-test.c
> >> +++ b/tests/bios-tables-test.c
> >> @@ -112,7 +112,7 @@ typedef struct {
> >>      g_assert_cmpstr(ACPI_ASSERT_CMP_str, ==, expected); \
> >>  } while (0)
> >>  
> >> -static const char *disk = "tests/acpi-test-disk.raw";
> >> +static char disk[] = "tests/acpi-test-disk-XXXXXX";
> >>  static const char *data_dir = "tests/acpi-test-data";
> >>  #ifdef CONFIG_IASL
> >>  static const char *iasl = stringify(CONFIG_IASL);
> >> diff --git a/tests/boot-sector.c b/tests/boot-sector.c
> >> index e3193c0..e75572f 100644
> >> --- a/tests/boot-sector.c
> >> +++ b/tests/boot-sector.c
> >> @@ -69,10 +69,15 @@ static uint8_t boot_sector[0x7e000] = {
> >>  };
> >>  
> >>  /* Create boot disk file.  */
> >> -int boot_sector_init(const char *fname)
> >> +int boot_sector_init(char *fname)
> >>  {
> >> -    FILE *f = fopen(fname, "w");
> >> +    FILE *f = NULL;
> >> +    int fd;
> >>  
> >> +    fd = mkstemp(fname);
> >> +    if (fd != -1) {
> >> +        f = fdopen(fd, "w");
> >> +    }  
> > 
> > Unless we really want to control how the temporary file is named (maybe for
> > debugging purpose?), I have the impression that using tmpfile(3) would result
> > in a simpler patch.  
> 
> That unfortunately does not work here - the file name is needed for
> starting the QEMU process later (see test_acpi_one() or test_pxe_one()
> for details).
> 

Oops you're right *of course*.

Then I guess Peter's remark on fwrite()/fclose() should also be addressed, but I
see you already sent an update for that :)

>  Thomas
> 

Cheers.

--
Greg