Re: [Qemu-devel] [PATCHv3 2/2] envlist.c: handle strdup failure
Andreas Färber wrote:
> Am 22.05.2012 12:16, schrieb Jim Meyering:
>> From: Jim Meyering
>>
>> Without this, envlist_to_environ may silently fail to copy all
>> strings into the destination buffer, and both callers would leak
>> any env strings allocated after a failing strdup, because the
>> freeing code stops at the first NULL pointer.
>>
>> Signed-off-by: Jim Meyering
>> ---
>> envlist.c | 12 ++--
>> 1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/envlist.c b/envlist.c
>> index e44889b..df5c723 100644
>> --- a/envlist.c
>> +++ b/envlist.c
>> @@ -234,8 +234,16 @@ envlist_to_environ(const envlist_t *envlist, size_t
>> *count)
>> return (NULL);
>>
>> for (entry = envlist->el_entries.lh_first; entry != NULL;
>> -entry = entry->ev_link.le_next) {
>> -*(penv++) = strdup(entry->ev_var);
>> + entry = entry->ev_link.le_next, penv++) {
>
> Scratch my comment on 1/2, there's an added penv++ that I overlooked.
> Not changing the indentation twice would still be nice.
I posted a V4 that does that, and removes parens around return arguments
as well. However, I did not remove assignments from conditionals. IMHO,
that would require an inordinate amount of change for the marginal gain
of making legacy code conform.
Re: [Qemu-devel] [PATCHv3 2/2] envlist.c: handle strdup failure
Am 22.05.2012 12:16, schrieb Jim Meyering:
> From: Jim Meyering
>
> Without this, envlist_to_environ may silently fail to copy all
> strings into the destination buffer, and both callers would leak
> any env strings allocated after a failing strdup, because the
> freeing code stops at the first NULL pointer.
>
> Signed-off-by: Jim Meyering
> ---
> envlist.c | 12 ++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/envlist.c b/envlist.c
> index e44889b..df5c723 100644
> --- a/envlist.c
> +++ b/envlist.c
> @@ -234,8 +234,16 @@ envlist_to_environ(const envlist_t *envlist, size_t
> *count)
> return (NULL);
>
> for (entry = envlist->el_entries.lh_first; entry != NULL;
> -entry = entry->ev_link.le_next) {
> -*(penv++) = strdup(entry->ev_var);
> + entry = entry->ev_link.le_next, penv++) {
Scratch my comment on 1/2, there's an added penv++ that I overlooked.
Not changing the indentation twice would still be nice.
> +*penv = strdup(entry->ev_var);
> +if (*penv == NULL) {
> +char **e = env;
> +while (e <= penv) {
> +free(*e++);
> +}
> +free(env);
> +return NULL;
> +}
> }
> *penv = NULL; /* NULL terminate the list */
>
This leak fix looks good then.
For anyone wondering like me, the "env" here is not the usual
CPUArchState *env but a local char **env.
Andreas
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[Qemu-devel] [PATCHv3 2/2] envlist.c: handle strdup failure
From: Jim Meyering
Without this, envlist_to_environ may silently fail to copy all
strings into the destination buffer, and both callers would leak
any env strings allocated after a failing strdup, because the
freeing code stops at the first NULL pointer.
Signed-off-by: Jim Meyering
---
envlist.c | 12 ++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/envlist.c b/envlist.c
index e44889b..df5c723 100644
--- a/envlist.c
+++ b/envlist.c
@@ -234,8 +234,16 @@ envlist_to_environ(const envlist_t *envlist, size_t *count)
return (NULL);
for (entry = envlist->el_entries.lh_first; entry != NULL;
-entry = entry->ev_link.le_next) {
-*(penv++) = strdup(entry->ev_var);
+ entry = entry->ev_link.le_next, penv++) {
+*penv = strdup(entry->ev_var);
+if (*penv == NULL) {
+char **e = env;
+while (e <= penv) {
+free(*e++);
+}
+free(env);
+return NULL;
+}
}
*penv = NULL; /* NULL terminate the list */
--
1.7.10.2.552.gaa3bb87
