* [Qemu-trivial] [PATCH] libcacard: fix wrong array expansion logic
@ 2014-05-23 20:57 ` Michael Tokarev
0 siblings, 0 replies; 6+ messages in thread
From: Michael Tokarev @ 2014-05-23 20:57 UTC (permalink / raw)
To: qemu-devel; +Cc: qemu-trivial, Michael Tokarev, alevy, Markus Armbruster
The currrent code in libcacard/vcard_emul_nss.c:vcard_emul_options()
has a weird bug in variable usage around expanding opts->vreader
array.
There's a helper variable, vreaderOpt, which is first needlessly
initialized to NULL, next, conditionally, only we have to expand
opts->vreader, receives array expansion from g_renew() (initially
realloc), and next, even if we don't actually perform expansion,
the value of this variable is assigned to the actual array,
opts->vreader, which was supposed to be expanded.
So, since we expand the array by READER_STEP increments, only
once in READER_STEP (=4) the code will work, in other 3/4 times
it will fail badly.
Fix this by not using this temp variable when expanding the
array, and by dropping the useless =NULL initializer too -
if it wasn't in place initially, compiler warned us about
this problem at the beginning.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
libcacard/vcard_emul_nss.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/libcacard/vcard_emul_nss.c b/libcacard/vcard_emul_nss.c
index b7db51d..8462aef 100644
--- a/libcacard/vcard_emul_nss.c
+++ b/libcacard/vcard_emul_nss.c
@@ -1149,7 +1149,7 @@ vcard_emul_options(const char *args)
char type_str[100];
VCardEmulType type;
int count, i;
- VirtualReaderOptions *vreaderOpt = NULL;
+ VirtualReaderOptions *vreaderOpt;
args = strip(args + 5);
if (*args != '(') {
@@ -1173,11 +1173,10 @@ vcard_emul_options(const char *args)
if (opts->vreader_count >= reader_count) {
reader_count += READER_STEP;
- vreaderOpt = g_renew(VirtualReaderOptions, opts->vreader,
- reader_count);
+ opts->vreader = g_renew(VirtualReaderOptions, opts->vreader,
+ reader_count);
}
- opts->vreader = vreaderOpt;
- vreaderOpt = &vreaderOpt[opts->vreader_count];
+ vreaderOpt = &opts->vreader[opts->vreader_count];
vreaderOpt->name = g_strndup(name, name_length);
vreaderOpt->vname = g_strndup(vname, vname_length);
vreaderOpt->card_type = type;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [Qemu-devel] [PATCH] libcacard: fix wrong array expansion logic
@ 2014-05-23 20:57 ` Michael Tokarev
0 siblings, 0 replies; 6+ messages in thread
From: Michael Tokarev @ 2014-05-23 20:57 UTC (permalink / raw)
To: qemu-devel; +Cc: qemu-trivial, Michael Tokarev, alevy, Markus Armbruster
The currrent code in libcacard/vcard_emul_nss.c:vcard_emul_options()
has a weird bug in variable usage around expanding opts->vreader
array.
There's a helper variable, vreaderOpt, which is first needlessly
initialized to NULL, next, conditionally, only we have to expand
opts->vreader, receives array expansion from g_renew() (initially
realloc), and next, even if we don't actually perform expansion,
the value of this variable is assigned to the actual array,
opts->vreader, which was supposed to be expanded.
So, since we expand the array by READER_STEP increments, only
once in READER_STEP (=4) the code will work, in other 3/4 times
it will fail badly.
Fix this by not using this temp variable when expanding the
array, and by dropping the useless =NULL initializer too -
if it wasn't in place initially, compiler warned us about
this problem at the beginning.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
libcacard/vcard_emul_nss.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/libcacard/vcard_emul_nss.c b/libcacard/vcard_emul_nss.c
index b7db51d..8462aef 100644
--- a/libcacard/vcard_emul_nss.c
+++ b/libcacard/vcard_emul_nss.c
@@ -1149,7 +1149,7 @@ vcard_emul_options(const char *args)
char type_str[100];
VCardEmulType type;
int count, i;
- VirtualReaderOptions *vreaderOpt = NULL;
+ VirtualReaderOptions *vreaderOpt;
args = strip(args + 5);
if (*args != '(') {
@@ -1173,11 +1173,10 @@ vcard_emul_options(const char *args)
if (opts->vreader_count >= reader_count) {
reader_count += READER_STEP;
- vreaderOpt = g_renew(VirtualReaderOptions, opts->vreader,
- reader_count);
+ opts->vreader = g_renew(VirtualReaderOptions, opts->vreader,
+ reader_count);
}
- opts->vreader = vreaderOpt;
- vreaderOpt = &vreaderOpt[opts->vreader_count];
+ vreaderOpt = &opts->vreader[opts->vreader_count];
vreaderOpt->name = g_strndup(name, name_length);
vreaderOpt->vname = g_strndup(vname, vname_length);
vreaderOpt->card_type = type;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [Qemu-trivial] [Qemu-devel] [PATCH] libcacard: fix wrong array expansion logic
2014-05-23 20:57 ` [Qemu-devel] " Michael Tokarev
@ 2014-05-26 6:25 ` Markus Armbruster
-1 siblings, 0 replies; 6+ messages in thread
From: Markus Armbruster @ 2014-05-26 6:25 UTC (permalink / raw)
To: Michael Tokarev; +Cc: qemu-trivial, alevy, qemu-devel
Michael Tokarev <mjt@tls.msk.ru> writes:
> The currrent code in libcacard/vcard_emul_nss.c:vcard_emul_options()
> has a weird bug in variable usage around expanding opts->vreader
> array.
>
> There's a helper variable, vreaderOpt, which is first needlessly
> initialized to NULL, next, conditionally, only we have to expand
> opts->vreader, receives array expansion from g_renew() (initially
> realloc), and next, even if we don't actually perform expansion,
I don't get the "(initially realloc)" part. The sentence makes sense to
me just fine without it, though.
> the value of this variable is assigned to the actual array,
> opts->vreader, which was supposed to be expanded.
>
> So, since we expand the array by READER_STEP increments, only
> once in READER_STEP (=4) the code will work, in other 3/4 times
> it will fail badly.
>
> Fix this by not using this temp variable when expanding the
> array, and by dropping the useless =NULL initializer too -
> if it wasn't in place initially, compiler warned us about
"would have warned us"?
> this problem at the beginning.
>
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
> libcacard/vcard_emul_nss.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/libcacard/vcard_emul_nss.c b/libcacard/vcard_emul_nss.c
> index b7db51d..8462aef 100644
> --- a/libcacard/vcard_emul_nss.c
> +++ b/libcacard/vcard_emul_nss.c
> @@ -1149,7 +1149,7 @@ vcard_emul_options(const char *args)
> char type_str[100];
> VCardEmulType type;
> int count, i;
> - VirtualReaderOptions *vreaderOpt = NULL;
> + VirtualReaderOptions *vreaderOpt;
>
> args = strip(args + 5);
> if (*args != '(') {
> @@ -1173,11 +1173,10 @@ vcard_emul_options(const char *args)
>
> if (opts->vreader_count >= reader_count) {
> reader_count += READER_STEP;
> - vreaderOpt = g_renew(VirtualReaderOptions, opts->vreader,
> - reader_count);
> + opts->vreader = g_renew(VirtualReaderOptions, opts->vreader,
> + reader_count);
> }
> - opts->vreader = vreaderOpt;
> - vreaderOpt = &vreaderOpt[opts->vreader_count];
> + vreaderOpt = &opts->vreader[opts->vreader_count];
> vreaderOpt->name = g_strndup(name, name_length);
> vreaderOpt->vname = g_strndup(vname, vname_length);
> vreaderOpt->card_type = type;
Much more straightforward now. Thanks!
Reviewed-by: Markus Armbruster <armbru@redhat.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-devel] [PATCH] libcacard: fix wrong array expansion logic
@ 2014-05-26 6:25 ` Markus Armbruster
0 siblings, 0 replies; 6+ messages in thread
From: Markus Armbruster @ 2014-05-26 6:25 UTC (permalink / raw)
To: Michael Tokarev; +Cc: qemu-trivial, alevy, qemu-devel
Michael Tokarev <mjt@tls.msk.ru> writes:
> The currrent code in libcacard/vcard_emul_nss.c:vcard_emul_options()
> has a weird bug in variable usage around expanding opts->vreader
> array.
>
> There's a helper variable, vreaderOpt, which is first needlessly
> initialized to NULL, next, conditionally, only we have to expand
> opts->vreader, receives array expansion from g_renew() (initially
> realloc), and next, even if we don't actually perform expansion,
I don't get the "(initially realloc)" part. The sentence makes sense to
me just fine without it, though.
> the value of this variable is assigned to the actual array,
> opts->vreader, which was supposed to be expanded.
>
> So, since we expand the array by READER_STEP increments, only
> once in READER_STEP (=4) the code will work, in other 3/4 times
> it will fail badly.
>
> Fix this by not using this temp variable when expanding the
> array, and by dropping the useless =NULL initializer too -
> if it wasn't in place initially, compiler warned us about
"would have warned us"?
> this problem at the beginning.
>
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
> libcacard/vcard_emul_nss.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/libcacard/vcard_emul_nss.c b/libcacard/vcard_emul_nss.c
> index b7db51d..8462aef 100644
> --- a/libcacard/vcard_emul_nss.c
> +++ b/libcacard/vcard_emul_nss.c
> @@ -1149,7 +1149,7 @@ vcard_emul_options(const char *args)
> char type_str[100];
> VCardEmulType type;
> int count, i;
> - VirtualReaderOptions *vreaderOpt = NULL;
> + VirtualReaderOptions *vreaderOpt;
>
> args = strip(args + 5);
> if (*args != '(') {
> @@ -1173,11 +1173,10 @@ vcard_emul_options(const char *args)
>
> if (opts->vreader_count >= reader_count) {
> reader_count += READER_STEP;
> - vreaderOpt = g_renew(VirtualReaderOptions, opts->vreader,
> - reader_count);
> + opts->vreader = g_renew(VirtualReaderOptions, opts->vreader,
> + reader_count);
> }
> - opts->vreader = vreaderOpt;
> - vreaderOpt = &vreaderOpt[opts->vreader_count];
> + vreaderOpt = &opts->vreader[opts->vreader_count];
> vreaderOpt->name = g_strndup(name, name_length);
> vreaderOpt->vname = g_strndup(vname, vname_length);
> vreaderOpt->card_type = type;
Much more straightforward now. Thanks!
Reviewed-by: Markus Armbruster <armbru@redhat.com>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [Qemu-trivial] [Qemu-devel] [PATCH] libcacard: fix wrong array expansion logic
2014-05-26 6:25 ` Markus Armbruster
@ 2014-05-26 6:29 ` Michael Tokarev
-1 siblings, 0 replies; 6+ messages in thread
From: Michael Tokarev @ 2014-05-26 6:29 UTC (permalink / raw)
To: Markus Armbruster; +Cc: qemu-trivial, alevy, qemu-devel
26.05.2014 10:25, Markus Armbruster wrote:
> Michael Tokarev <mjt@tls.msk.ru> writes:
>
>> The currrent code in libcacard/vcard_emul_nss.c:vcard_emul_options()
>> has a weird bug in variable usage around expanding opts->vreader
>> array.
>>
>> There's a helper variable, vreaderOpt, which is first needlessly
>> initialized to NULL, next, conditionally, only we have to expand
>> opts->vreader, receives array expansion from g_renew() (initially
>> realloc), and next, even if we don't actually perform expansion,
>
> I don't get the "(initially realloc)" part. The sentence makes sense to
> me just fine without it, though.
I was in context of your patch which changes realloc() to g_renew().
And I failed to mention that this my patch is on top of yuors,
too - think of this comment as such a mention ;)
>> the value of this variable is assigned to the actual array,
>> opts->vreader, which was supposed to be expanded.
>>
>> So, since we expand the array by READER_STEP increments, only
>> once in READER_STEP (=4) the code will work, in other 3/4 times
>> it will fail badly.
>>
>> Fix this by not using this temp variable when expanding the
>> array, and by dropping the useless =NULL initializer too -
>> if it wasn't in place initially, compiler warned us about
>
> "would have warned us"?
Oh yeah. I tried to remember the right English construct, but
failed. This tense always escpapes my mind for some reason :)
> Much more straightforward now. Thanks!
>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
Thank you. I'll fix the comment. And I'm now ready to push
whole -trivial.
/mjt
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] [PATCH] libcacard: fix wrong array expansion logic
@ 2014-05-26 6:29 ` Michael Tokarev
0 siblings, 0 replies; 6+ messages in thread
From: Michael Tokarev @ 2014-05-26 6:29 UTC (permalink / raw)
To: Markus Armbruster; +Cc: qemu-trivial, alevy, qemu-devel
26.05.2014 10:25, Markus Armbruster wrote:
> Michael Tokarev <mjt@tls.msk.ru> writes:
>
>> The currrent code in libcacard/vcard_emul_nss.c:vcard_emul_options()
>> has a weird bug in variable usage around expanding opts->vreader
>> array.
>>
>> There's a helper variable, vreaderOpt, which is first needlessly
>> initialized to NULL, next, conditionally, only we have to expand
>> opts->vreader, receives array expansion from g_renew() (initially
>> realloc), and next, even if we don't actually perform expansion,
>
> I don't get the "(initially realloc)" part. The sentence makes sense to
> me just fine without it, though.
I was in context of your patch which changes realloc() to g_renew().
And I failed to mention that this my patch is on top of yuors,
too - think of this comment as such a mention ;)
>> the value of this variable is assigned to the actual array,
>> opts->vreader, which was supposed to be expanded.
>>
>> So, since we expand the array by READER_STEP increments, only
>> once in READER_STEP (=4) the code will work, in other 3/4 times
>> it will fail badly.
>>
>> Fix this by not using this temp variable when expanding the
>> array, and by dropping the useless =NULL initializer too -
>> if it wasn't in place initially, compiler warned us about
>
> "would have warned us"?
Oh yeah. I tried to remember the right English construct, but
failed. This tense always escpapes my mind for some reason :)
> Much more straightforward now. Thanks!
>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
Thank you. I'll fix the comment. And I'm now ready to push
whole -trivial.
/mjt
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2014-05-26 6:30 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2014-05-23 20:57 [Qemu-trivial] [PATCH] libcacard: fix wrong array expansion logic Michael Tokarev
2014-05-23 20:57 ` [Qemu-devel] " Michael Tokarev
2014-05-26 6:25 ` [Qemu-trivial] " Markus Armbruster
2014-05-26 6:25 ` Markus Armbruster
2014-05-26 6:29 ` [Qemu-trivial] " Michael Tokarev
2014-05-26 6:29 ` Michael Tokarev
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