handle xlat_styles when decoding sa_mask
shankarapailoor
shankarapailoor at gmail.com
Sat Mar 23 17:01:14 UTC 2019
Hi Dmitry,
Sorry for the late reply but when you say "explicit length" do you mean the
long should be printed the same string length regardless of architecture?
On Sun, Mar 17, 2019 at 3:42 PM Dmitry V. Levin <ldv at altlinux.org> wrote:
> Hi,
>
> On Sun, Feb 17, 2019 at 12:43:59PM -0600, shankarapailoor wrote:
> > Hi,
> >
> > > I hope you understand that the output produced by your parser
> > > is different between big-endian and little-endian architectures.
> >
> > Yes I understood. How do you think we should decode the sa_mask field
> under
> > XLAT_RAW?
>
> There seems to be no obvious way of printing sa_mask under XLAT_RAW,
> so the question is how to print sa_mask under XLAT_RAW
> in the least confusing way.
>
> Since sa_mask is implemented as an array of target long integers,
> what if we printed sa_mask as an array of hexadecimal values with explicit
> length, e.g. tprintf("%#0*" PRI_klx, (int) elem_size * 2 + 2, elem_value)?
>
> > On Fri, Feb 8, 2019 at 1:46 PM Dmitry V. Levin <ldv at altlinux.org> wrote:
> >
> > > On Fri, Feb 08, 2019 at 10:32:52PM +0300, Dmitry V. Levin wrote:
> > > > Hi,
> > > >
> > > > On Sat, Jan 05, 2019 at 12:10:38PM -0800, shankarapailoor wrote:
> > > > > Hi,
> > > > >
> > > > > Strace doesn't handle xlat styles properly when decoding the
> sa_mask
> > > > > field of the sigaction struct, Attached is a patch which decodes
> the
> > > > > field as an array of bytes. Let me know what you think!
> > > > >
> > > > > Regards,
> > > > > Shankara Pailoor
> > > >
> > > > > From 41d7cac5cf000f4e8b6ee675d231038cb786d2e1 Mon Sep 17 00:00:00
> 2001
> > > > > From: Shankara Pailoor <shankarapailoor at gmail.com>
> > > > > Date: Sat, 5 Jan 2019 11:49:28 -0800
> > > > > Subject: [PATCH v1] properly handle xlat_styles when decoding
> > > sigaction mask
> > > > >
> > > > > * signal.c (sprintsigmask_n): Decode sigaction mask as array of
> bytes
> > > under XLAT_RAW, VERBOSE.
> > > > > * tests/printsamask.c: New file.
> > > > > * tests/printsamask-Xabbrev.c: Likewise.
> > > > > * tests/printsamask-Xraw.c: Likewise.
> > > > > * tests/printsamask-Xverbose.c: Likewise.
> > > > > * tests/pure_executables.list: Add printsamask-Xabbrev,
> > > printsamask-Xraw, printsamask-Xverbose.
> > > > > * tests/gen_tests.in: Likewise.
> > > > > ---
> > > > > signal.c | 32 +++++++++++++-
> > > > > tests/.gitignore | 3 ++
> > > > > tests/gen_tests.in | 3 ++
> > > > > tests/printsamask-Xabbrev.c | 1 +
> > > > > tests/printsamask-Xraw.c | 2 +
> > > > > tests/printsamask-Xverbose.c | 2 +
> > > > > tests/printsamask.c | 81
> ++++++++++++++++++++++++++++++++++++
> > > > > tests/pure_executables.list | 3 ++
> > > > > 8 files changed, 126 insertions(+), 1 deletion(-)
> > > > > create mode 100644 tests/printsamask-Xabbrev.c
> > > > > create mode 100644 tests/printsamask-Xraw.c
> > > > > create mode 100644 tests/printsamask-Xverbose.c
> > > > > create mode 100644 tests/printsamask.c
> > > > >
> > > > > diff --git a/signal.c b/signal.c
> > > > > index 418905f0..e3c5d8c3 100644
> > > > > --- a/signal.c
> > > > > +++ b/signal.c
> > > > > @@ -166,8 +166,11 @@ sprintsigmask_n(const char *prefix, const void
> > > *sig_mask, unsigned int bytes)
> > > > > * Most of signal names have length 7,
> > > > > * average length of signal names is less than 7.
> > > > > * The length of prefix string does not exceed 16.
> > > > > + * Under xlat_verbose we may have at most NSIG_BYTES in
> > > > > + * the raw sa_mask array. We can safely allocate 8 bytes per
> entry
> > > > > */
> > > > > - static char outstr[128 + 8 * (NSIG_BYTES * 8 * 2 / 3)];
> > > > > + static char outstr[128 + 8 * (NSIG_BYTES * 8 * 2 / 3)
> > > > > + + 8 * NSIG_BYTES];
> > > > >
> > > > > char *s;
> > > > > const uint32_t *mask;
> > > > > @@ -178,6 +181,29 @@ sprintsigmask_n(const char *prefix, const void
> > > *sig_mask, unsigned int bytes)
> > > > >
> > > > > s = stpcpy(outstr, prefix);
> > > > >
> > > > > + if (xlat_verbose(xlat_verbosity) != XLAT_STYLE_ABBREV) {
> > > > > + const char *mask = (char *) sig_mask;
> > > > > + const char *sep = "[";
> > > > > + unsigned int i, size;
> > > > > +
> > > > > + size = (bytes >= NSIG_BYTES) ? NSIG_BYTES : bytes;
> > > > > + for (i = 0; i < size; i++) {
> > > > > + s = xappendstr(outstr, s, "%s0x%02x", sep,
> > > mask[i]);
> > > > > + sep = ", ";
> > > > > + }
> > > >
> > > > I hope you understand that the output produced by your parser
> > > > is different between big-endian and little-endian architectures.
> > > >
> > > > [...]
> > > > > +int
> > > > > +main(void)
> > > > > +{
> > > > > + unsigned int set_size = NSIG / 8;
> > > > > + void *const k_set = tail_alloc(set_size);
> > > > > + void *const old_set = tail_alloc(set_size);
> > > > > + TAIL_ALLOC_OBJECT_CONST_PTR(sigset_t, libc_set);
> > > > > +
> > > > > + memset(k_set, 0, set_size);
> > > > > + sigemptyset(libc_set);
> > > > > + sigaddset(libc_set, SIGHUP);
> > > > > + memcpy(k_set, libc_set, set_size);
> > > > > +
> > > > > + int rc = k_sigprocmask(SIG_SETMASK, k_set, old_set, set_size);
> > > > > +#if XLAT_RAW
> > > > > + tprintf("rt_sigprocmask(0x2"
> > > > > + ", [0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]"
> > > > > + ", [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]"
> > > > > + ", %u) = %s\n", set_size, sprintrc(rc));
> > > > > +#elif XLAT_VERBOSE
> > > > > + tprintf("rt_sigprocmask(0x2 /* SIG_SETMASK */"
> > > > > + ", [0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] /*
> > > [HUP] */"
> > > > > + ", [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] /*
> []
> > > */, %u) = %s\n",
> > > > > + set_size, sprintrc(rc));
> > > > > +#else /* XLAT_ABBREV */
> > > > > + tprintf("rt_sigprocmask(SIG_SETMASK, [HUP], [], %u) = %s\n",
> > > > > + set_size, sprintrc(rc));
> > > > > +#endif
> > > >
> > > > Your test assumes that the output is produced on a big-endian
> > >
> > > s/big-endian/little-endian/
> > >
> > > > architecture, so it fails on big-endian architectures.
>
>
> --
> ldv
> --
> Strace-devel mailing list
> Strace-devel at lists.strace.io
> https://lists.strace.io/mailman/listinfo/strace-devel
>
--
Regards,
Shankara Pailoor
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