* [PATCH] Fix GDBHISTSIZE test failure on i686
@ 2015-06-23 14:31 Patrick Palka
2015-06-23 14:46 ` Patrick Palka
2015-06-23 17:19 ` Pedro Alves
0 siblings, 2 replies; 5+ messages in thread
From: Patrick Palka @ 2015-06-23 14:31 UTC (permalink / raw)
To: gdb-patches; +Cc: Patrick Palka
The test
test_histsize_history_setting "99999999999999999999999999999999999" "unlimited"
was failing on i686 because the condition in init_history() for
determining whether to map a large GDBHISTSIZE value to infinity was
long var = strtol (tmpenv);
if (var > INT_MAX)
history_size = unlimited;
but this condition is never true on i686 because INT_MAX == LONG_MAX.
So in order to properly map large out-of-range values of GDBHISTSIZE to
infinity on targets where LONG_MAX > INT_MAX as well as on i686, we have
to instead change the above condition to
if (var > INT_MAX
|| (var == INT_MAX && errno == ERANGE))
history_size = unlimited;
[ I did not test this patch on i686 because I don't have access to
such a machine. But the patch seems straightforward enough... ]
gdb/ChangeLog:
* top.c (init_history): Look at the errno set by strtol to
properly map large GDBHISTSIZE values to infinity.
---
gdb/top.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/gdb/top.c b/gdb/top.c
index 5114c2e..afb14be 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1734,10 +1734,12 @@ init_history (void)
if (tmpenv)
{
long var;
+ int saved_errno;
char *endptr;
tmpenv = skip_spaces (tmpenv);
var = strtol (tmpenv, &endptr, 10);
+ saved_errno = errno;
endptr = skip_spaces (endptr);
/* If GDBHISTSIZE is non-numeric then ignore it. If GDBHISTSIZE is the
@@ -1749,7 +1751,12 @@ init_history (void)
;
else if (*tmpenv == '\0'
|| var < 0
- || var > INT_MAX)
+ || var > INT_MAX
+ /* On targets where INT_MAX == LONG_MAX, we have to look at
+ the errno set by strtol to distinguish between a value that
+ is exactly INT_MAX and an overflowing value that was clamped
+ to INT_MAX. */
+ || (var == INT_MAX && saved_errno == ERANGE))
history_size_setshow_var = -1;
else
history_size_setshow_var = var;
--
2.4.4.410.g43ed522.dirty
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix GDBHISTSIZE test failure on i686
2015-06-23 14:31 [PATCH] Fix GDBHISTSIZE test failure on i686 Patrick Palka
@ 2015-06-23 14:46 ` Patrick Palka
2015-06-23 17:19 ` Pedro Alves
1 sibling, 0 replies; 5+ messages in thread
From: Patrick Palka @ 2015-06-23 14:46 UTC (permalink / raw)
To: gdb-patches; +Cc: Patrick Palka
On Tue, Jun 23, 2015 at 10:30 AM, Patrick Palka <patrick@parcs.ath.cx> wrote:
> The test
>
> test_histsize_history_setting "99999999999999999999999999999999999" "unlimited"
>
> was failing on i686 because the condition in init_history() for
> determining whether to map a large GDBHISTSIZE value to infinity was
>
> long var = strtol (tmpenv);
> if (var > INT_MAX)
> history_size = unlimited;
>
> but this condition is never true on i686 because INT_MAX == LONG_MAX.
> So in order to properly map large out-of-range values of GDBHISTSIZE to
> infinity on targets where LONG_MAX > INT_MAX as well as on i686, we have
> to instead change the above condition to
>
> if (var > INT_MAX
> || (var == INT_MAX && errno == ERANGE))
> history_size = unlimited;
>
> [ I did not test this patch on i686 because I don't have access to
> such a machine. But the patch seems straightforward enough... ]
>
> gdb/ChangeLog:
>
> * top.c (init_history): Look at the errno set by strtol to
> properly map large GDBHISTSIZE values to infinity.
> ---
> gdb/top.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/gdb/top.c b/gdb/top.c
> index 5114c2e..afb14be 100644
> --- a/gdb/top.c
> +++ b/gdb/top.c
> @@ -1734,10 +1734,12 @@ init_history (void)
> if (tmpenv)
> {
> long var;
> + int saved_errno;
> char *endptr;
>
> tmpenv = skip_spaces (tmpenv);
> var = strtol (tmpenv, &endptr, 10);
> + saved_errno = errno;
errno should be set to 0 before the call to strtol.
> endptr = skip_spaces (endptr);
>
> /* If GDBHISTSIZE is non-numeric then ignore it. If GDBHISTSIZE is the
> @@ -1749,7 +1751,12 @@ init_history (void)
> ;
> else if (*tmpenv == '\0'
> || var < 0
> - || var > INT_MAX)
> + || var > INT_MAX
> + /* On targets where INT_MAX == LONG_MAX, we have to look at
> + the errno set by strtol to distinguish between a value that
> + is exactly INT_MAX and an overflowing value that was clamped
> + to INT_MAX. */
> + || (var == INT_MAX && saved_errno == ERANGE))
> history_size_setshow_var = -1;
> else
> history_size_setshow_var = var;
> --
> 2.4.4.410.g43ed522.dirty
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix GDBHISTSIZE test failure on i686
2015-06-23 14:31 [PATCH] Fix GDBHISTSIZE test failure on i686 Patrick Palka
2015-06-23 14:46 ` Patrick Palka
@ 2015-06-23 17:19 ` Pedro Alves
2015-06-23 17:42 ` Doug Evans
2015-06-23 19:36 ` Patrick Palka
1 sibling, 2 replies; 5+ messages in thread
From: Pedro Alves @ 2015-06-23 17:19 UTC (permalink / raw)
To: Patrick Palka, gdb-patches
On 06/23/2015 03:30 PM, Patrick Palka wrote:
> The test
>
> test_histsize_history_setting "99999999999999999999999999999999999" "unlimited"
>
> was failing on i686 because the condition in init_history() for
> determining whether to map a large GDBHISTSIZE value to infinity was
>
> long var = strtol (tmpenv);
> if (var > INT_MAX)
> history_size = unlimited;
>
> but this condition is never true on i686 because INT_MAX == LONG_MAX.
> So in order to properly map large out-of-range values of GDBHISTSIZE to
> infinity on targets where LONG_MAX > INT_MAX as well as on i686, we have
> to instead change the above condition to
>
> if (var > INT_MAX
> || (var == INT_MAX && errno == ERANGE))
> history_size = unlimited;
>
> [ I did not test this patch on i686 because I don't have access to
> such a machine. But the patch seems straightforward enough... ]
Looks fine to me, with the missing errno=0, but note that assuming you
install the 32-bit dependencies in your distro, you can easily build
a 32-bit gdb on a 64-bit host. E.g., on x86-64 GNU/Linux, configure with:
CC="gcc -m32" /path/to/configure \
--host=i686-pc-linux-gnu \
--build=i686-pc-linux-gnu \
--target=i686-pc-linux-gnu
Thanks,
Pedro Alves
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix GDBHISTSIZE test failure on i686
2015-06-23 17:19 ` Pedro Alves
@ 2015-06-23 17:42 ` Doug Evans
2015-06-23 19:36 ` Patrick Palka
1 sibling, 0 replies; 5+ messages in thread
From: Doug Evans @ 2015-06-23 17:42 UTC (permalink / raw)
To: Pedro Alves; +Cc: Patrick Palka, gdb-patches
On Tue, Jun 23, 2015 at 12:19 PM, Pedro Alves <palves@redhat.com> wrote:
>... note that assuming you
> install the 32-bit dependencies in your distro, you can easily build
> a 32-bit gdb on a 64-bit host. E.g., on x86-64 GNU/Linux, configure with:
>
> CC="gcc -m32" /path/to/configure \
> --host=i686-pc-linux-gnu \
> --build=i686-pc-linux-gnu \
> --target=i686-pc-linux-gnu
--host and --target can be elided here.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] Fix GDBHISTSIZE test failure on i686
2015-06-23 17:19 ` Pedro Alves
2015-06-23 17:42 ` Doug Evans
@ 2015-06-23 19:36 ` Patrick Palka
1 sibling, 0 replies; 5+ messages in thread
From: Patrick Palka @ 2015-06-23 19:36 UTC (permalink / raw)
To: Pedro Alves; +Cc: gdb-patches
On Tue, Jun 23, 2015 at 1:19 PM, Pedro Alves <palves@redhat.com> wrote:
> On 06/23/2015 03:30 PM, Patrick Palka wrote:
>> The test
>>
>> test_histsize_history_setting "99999999999999999999999999999999999" "unlimited"
>>
>> was failing on i686 because the condition in init_history() for
>> determining whether to map a large GDBHISTSIZE value to infinity was
>>
>> long var = strtol (tmpenv);
>> if (var > INT_MAX)
>> history_size = unlimited;
>>
>> but this condition is never true on i686 because INT_MAX == LONG_MAX.
>> So in order to properly map large out-of-range values of GDBHISTSIZE to
>> infinity on targets where LONG_MAX > INT_MAX as well as on i686, we have
>> to instead change the above condition to
>>
>> if (var > INT_MAX
>> || (var == INT_MAX && errno == ERANGE))
>> history_size = unlimited;
>>
>> [ I did not test this patch on i686 because I don't have access to
>> such a machine. But the patch seems straightforward enough... ]
>
> Looks fine to me, with the missing errno=0, but note that assuming you
> install the 32-bit dependencies in your distro, you can easily build
> a 32-bit gdb on a 64-bit host. E.g., on x86-64 GNU/Linux, configure with:
>
> CC="gcc -m32" /path/to/configure \
> --host=i686-pc-linux-gnu \
> --build=i686-pc-linux-gnu \
> --target=i686-pc-linux-gnu
Cool. I will commit the patch after confirming that it's fixed on
i686 this way.
>
> Thanks,
> Pedro Alves
>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2015-06-23 14:31 [PATCH] Fix GDBHISTSIZE test failure on i686 Patrick Palka
2015-06-23 14:46 ` Patrick Palka
2015-06-23 17:19 ` Pedro Alves
2015-06-23 17:42 ` Doug Evans
2015-06-23 19:36 ` Patrick Palka
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