elf: fix handling of negative numbers in dl-printf
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Description |
dj/TryBot-apply_patch |
success
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Patch applied to master at the time it was sent
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dj/TryBot-32bit |
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Build for i686
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Commit Message
_dl_debug_vdprintf is a bare-bones printf implementation; currently
printing a signed integer (using "%d" format specifier) behaves
incorrectly when the number is negative, as it just prints the
corresponding unsigned integer, preceeded by a minus sign.
For example, _dl_printf("%d", -1) would print '-4294967295'.
Signed-off-by: Roy Eldar <royeldar0@gmail.com>
---
elf/dl-printf.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
Comments
* Roy Eldar via Libc-alpha:
> _dl_debug_vdprintf is a bare-bones printf implementation; currently
> printing a signed integer (using "%d" format specifier) behaves
> incorrectly when the number is negative, as it just prints the
> corresponding unsigned integer, preceeded by a minus sign.
>
> For example, _dl_printf("%d", -1) would print '-4294967295'.
>
> Signed-off-by: Roy Eldar <royeldar0@gmail.com>
We've discussed this during our patch review call.
Ideally we'd want a separate test case for this routine. You could add
a statically-linked test case that calls _dl_debug_vdprintf directly
with a pipe descriptor. Is this something you'd be interested in
working on?
Thanks,
Florian
Hi,
First of all, thanks for the quick response.
Florian Weimer <fweimer@redhat.com> wrote:
> Ideally we'd want a separate test case for this routine. You could add
> a statically-linked test case that calls _dl_debug_vdprintf directly
> with a pipe descriptor. Is this something you'd be interested in
> working on?
I'll be happy to work on that.
Thanks,
Roy
Hi,
Is there any update on that?
I've written a test case for _dl_debug_vdprintf in a different patch [1].
[1] https://public-inbox.org/libc-alpha/20230515202942.8307-1-royeldar0@gmail.com/
* Roy Eldar via Libc-alpha:
> _dl_debug_vdprintf is a bare-bones printf implementation; currently
> printing a signed integer (using "%d" format specifier) behaves
> incorrectly when the number is negative, as it just prints the
> corresponding unsigned integer, preceeded by a minus sign.
>
> For example, _dl_printf("%d", -1) would print '-4294967295'.
>
> Signed-off-by: Roy Eldar <royeldar0@gmail.com>
> ---
> elf/dl-printf.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/elf/dl-printf.c b/elf/dl-printf.c
> index e8b9900370..977ac330b6 100644
> --- a/elf/dl-printf.c
> +++ b/elf/dl-printf.c
Please update the copyright staement with
Copyright The GNU Toolchain Authors.
Then I'm going to apply it together with the test.
Thanks,
Florian
@@ -150,19 +150,25 @@ _dl_debug_vdprintf (int fd, int tag_p, const char *fmt, va_list arg)
if (long_mod)
{
if ((long int) num < 0)
- negative = true;
+ {
+ num = -num;
+ negative = true;
+ }
}
else
{
if ((int) num < 0)
{
- num = (unsigned int) num;
+ num = -(unsigned int) num;
negative = true;
}
}
#else
if ((int) num < 0)
- negative = true;
+ {
+ num = -num;
+ negative = true;
+ }
#endif
}