[PATCH] block/curl.c: Use explicit long constants in curl_easy_setopt calls

[PATCH] block/curl.c: Use explicit long constants in curl_easy_setopt calls

[Richard W.M. Jones]

curl_easy_setopt takes a variable argument that depends on what
CURLOPT you are setting.  Some require a long constant.  Passing a
plain int constant is potentially wrong on some platforms.

With warnings enabled, multiple warnings like this were printed:

../block/curl.c: In function ‘curl_init_state’:
../block/curl.c:474:13: warning: call to ‘_curl_easy_setopt_err_long’ declared with attribute warning: curl_easy_setopt expects a long argument [-Wattribute-warning]
  474 |             curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1) ||
      |             ^

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
---
 block/curl.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/block/curl.c b/block/curl.c
index e0f98e035a..68cf83ce55 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -471,11 +471,11 @@ static int curl_init_state(BDRVCURLState *s, CURLState *state)
                              (void *)curl_read_cb) ||
             curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state) ||
             curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state) ||
-            curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1) ||
-            curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1) ||
-            curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1) ||
+            curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1L) ||
+            curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1L) ||
+            curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1L) ||
             curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg) ||
-            curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1)) {
+            curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1L)) {
             goto err;
         }
         if (s->username) {
@@ -800,7 +800,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     s->accept_range = false;
-    if (curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1) ||
+    if (curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1L) ||
         curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION, curl_header_cb) ||
         curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s)) {
         pstrcpy(state->errmsg, CURL_ERROR_SIZE,
-- 
2.50.1

Re: [PATCH] block/curl.c: Use explicit long constants in curl_easy_setopt calls

[Daniel P. Berrangé]

On Wed, Oct 01, 2025 at 01:40:47PM +0100, Richard W.M. Jones wrote:
> curl_easy_setopt takes a variable argument that depends on what
> CURLOPT you are setting.  Some require a long constant.  Passing a
> plain int constant is potentially wrong on some platforms.

In practice for QEMU I think this is all harmless, since we only target
GCC + CLang on a selection of modern platforms, so integer promotion
should work fine for int -> long. None the less, we need to squash the
warnings and don't want to turn off -Wattribute-warning entirely, so
this makes sense.

> 
> With warnings enabled, multiple warnings like this were printed:
> 
> ../block/curl.c: In function ‘curl_init_state’:
> ../block/curl.c:474:13: warning: call to ‘_curl_easy_setopt_err_long’ declared with attribute warning: curl_easy_setopt expects a long argument [-Wattribute-warning]
>   474 |             curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1) ||
>       |             ^
> 
> Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
> ---
>  block/curl.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
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