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According to Eric Blake on 8/19/2008 6:29 AM:
> According to Alain Guibert on 8/19/2008 4:40 AM:
>> Sure. There is a segfault on the test for large precisions, on
>> "%.4000d". On libc5 this format works well until "%.1020d", but
>> segfaults for "%.1021d" and above.
>
> Bruno, this looks like a vasnprintf bug, since configure accurately
> determined that:
>
>> | checking whether printf supports large precisions... no
>
> I'm not sure where to look in vasnprintf to try fixing this, although it
> seems like it might be as simple as using NEED_PRINTF_UNBOUNDED_PRECISION
> in more places. Do you have suggestions?
In looking at this further, it looks like line 4179 of vasnprintf.c should
_not_ count precision as a prefix if prec_ourselves is nonzero. Without
the patch to vasnprintf.c, the added test in test-vasnprintf-posix dumped
core when I used
$ gl_cv_func_printf_sizes_c99=no gl_cv_func_printf_infinite=no
gl_cv_func_printf_directive_a=no gl_cv_func_printf_directive_f=no
gl_cv_func_printf_flag_zero=no gl_cv_func_printf_precision=no
./gnulib-tool --with-tests --test vasnprintf-posix
on cygwin. I traced this to an attempt to call snprintf(buf, 12, "%d%n",
4000, 1234567, &count).
OK to apply? Are there other files in lib or tests that need matching
modifications?
- --
Don't work too hard, make some time for fun as well!
Eric Blake [EMAIL PROTECTED]
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>From e9d8a313d2d20e4286dea8302373837ad1b2d95a Mon Sep 17 00:00:00 2001
From: Eric Blake <[EMAIL PROTECTED]>
Date: Mon, 1 Sep 2008 21:28:44 -0600
Subject: [PATCH] vasnprintf-posix: handle large precision via %.*d
* lib/vasnprintf.c (VASNPRINTF): Don't pass precision to snprintf
when handling it ourselves.
* tests/test-vasnprintf-posix.c (test_function): Add test.
Reported by Alain Guibert.
Signed-off-by: Eric Blake <[EMAIL PROTECTED]>
---
ChangeLog | 6 ++++++
lib/vasnprintf.c | 2 +-
tests/test-vasnprintf-posix.c | 13 +++++++++++++
3 files changed, 20 insertions(+), 1 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 0277d1c..84c8ed6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2008-09-01 Eric Blake <[EMAIL PROTECTED]>
+ vasnprintf-posix: handle large precision via %.*d
+ * lib/vasnprintf.c (VASNPRINTF): Don't pass precision to snprintf
+ when handling it ourselves.
+ * tests/test-vasnprintf-posix.c (test_function): Add test.
+ Reported by Alain Guibert.
+
c-stack: make configure-time check more robust
* m4/c-stack.m4 (AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC): Check for
successful sigaction call.
diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c
index 89829c9..4ddf45f 100644
--- a/lib/vasnprintf.c
+++ b/lib/vasnprintf.c
@@ -4176,7 +4176,7 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
abort ();
prefixes[prefix_count++] =
a.arg[dp->width_arg_index].a.a_int;
}
- if (dp->precision_arg_index != ARG_NONE)
+ if (!prec_ourselves && dp->precision_arg_index != ARG_NONE)
{
if (!(a.arg[dp->precision_arg_index].type == TYPE_INT))
abort ();
diff --git a/tests/test-vasnprintf-posix.c b/tests/test-vasnprintf-posix.c
index 42d9267..4c9d47e 100644
--- a/tests/test-vasnprintf-posix.c
+++ b/tests/test-vasnprintf-posix.c
@@ -3457,6 +3457,19 @@ test_function (char * (*my_asnprintf) (char *, size_t *,
const char *, ...))
{
size_t length;
char *result =
+ my_asnprintf (NULL, &length, "%.*d %d", 4000, 1234567, 99);
+ size_t i;
+ ASSERT (result != NULL);
+ for (i = 0; i < 4000 - 7; i++)
+ ASSERT (result[i] == '0');
+ ASSERT (strcmp (result + 4000 - 7, "1234567 99") == 0);
+ ASSERT (length == strlen (result));
+ free (result);
+ }
+
+ {
+ size_t length;
+ char *result =
my_asnprintf (NULL, &length, "%.4000d %d", -1234567, 99);
size_t i;
ASSERT (result != NULL);
--
1.6.0
