diff mbox series

block/curl: explicitly assert that strchr returns non-NULL value

Message ID 20240627153059.589070-1-vsementsov@yandex-team.ru (mailing list archive)
State New
Headers show
Series block/curl: explicitly assert that strchr returns non-NULL value | expand

Commit Message

Vladimir Sementsov-Ogievskiy June 27, 2024, 3:30 p.m. UTC
strchr may return NULL if colon is not found. It seems clearer to
assert explicitly that we don't expect it here, than dereference 1 in
the next line.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
 block/curl.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Kevin Wolf June 27, 2024, 6:05 p.m. UTC | #1
Am 27.06.2024 um 17:30 hat Vladimir Sementsov-Ogievskiy geschrieben:
> strchr may return NULL if colon is not found. It seems clearer to
> assert explicitly that we don't expect it here, than dereference 1 in
> the next line.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
>  block/curl.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/block/curl.c b/block/curl.c
> index 419f7c89ef..ccfffd6c12 100644
> --- a/block/curl.c
> +++ b/block/curl.c
> @@ -219,7 +219,9 @@ static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
>          && g_ascii_strncasecmp(header, accept_ranges,
>                                 strlen(accept_ranges)) == 0) {
>  
> -        char *p = strchr(header, ':') + 1;
> +        char *p = strchr(header, ':');
> +        assert(p != NULL);
> +        p += 1;

I'm not sure if this is actually much clearer because it doesn't say why
we don't expect NULL here. If you don't look at the context, it almost
looks like an assert() where proper error handling is needed. If you do,
then the original line is clear enough.

My first thought was that maybe what we want is a comment, but we
actually already know where the colon is. So how about this instead:

    char *p = header + strlen(accept_ranges);

Kevin

>          /* Skip whitespace between the header name and value. */
>          while (p < end && *p && g_ascii_isspace(*p)) {
> -- 
> 2.34.1
>
Vladimir Sementsov-Ogievskiy June 28, 2024, 5:34 a.m. UTC | #2
On 27.06.24 21:05, Kevin Wolf wrote:
> Am 27.06.2024 um 17:30 hat Vladimir Sementsov-Ogievskiy geschrieben:
>> strchr may return NULL if colon is not found. It seems clearer to
>> assert explicitly that we don't expect it here, than dereference 1 in
>> the next line.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
>> ---
>>   block/curl.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/block/curl.c b/block/curl.c
>> index 419f7c89ef..ccfffd6c12 100644
>> --- a/block/curl.c
>> +++ b/block/curl.c
>> @@ -219,7 +219,9 @@ static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
>>           && g_ascii_strncasecmp(header, accept_ranges,
>>                                  strlen(accept_ranges)) == 0) {
>>   
>> -        char *p = strchr(header, ':') + 1;
>> +        char *p = strchr(header, ':');
>> +        assert(p != NULL);
>> +        p += 1;
> 
> I'm not sure if this is actually much clearer because it doesn't say why
> we don't expect NULL here. If you don't look at the context, it almost
> looks like an assert() where proper error handling is needed. If you do,
> then the original line is clear enough.
> 
> My first thought was that maybe what we want is a comment, but we
> actually already know where the colon is. So how about this instead:
> 
>      char *p = header + strlen(accept_ranges);
> 

Oh, right. That's better.

> 
>>           /* Skip whitespace between the header name and value. */
>>           while (p < end && *p && g_ascii_isspace(*p)) {
>> -- 
>> 2.34.1
>>
>
diff mbox series

Patch

diff --git a/block/curl.c b/block/curl.c
index 419f7c89ef..ccfffd6c12 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -219,7 +219,9 @@  static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
         && g_ascii_strncasecmp(header, accept_ranges,
                                strlen(accept_ranges)) == 0) {
 
-        char *p = strchr(header, ':') + 1;
+        char *p = strchr(header, ':');
+        assert(p != NULL);
+        p += 1;
 
         /* Skip whitespace between the header name and value. */
         while (p < end && *p && g_ascii_isspace(*p)) {