| Message ID | 20230503211641.5742-1-royeldar0@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | elf: fix handling of negative numbers in dl-printf | expand |
* 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
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 @@ -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 }
_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(-)