[RFC v5 084/126] SLIRP: introduce ERRP_AUTO_PROPAGATE

Vladimir Sementsov-Ogievskiy posted 126 patches 6 years, 3 months ago
[RFC v5 084/126] SLIRP: introduce ERRP_AUTO_PROPAGATE
Posted by Vladimir Sementsov-Ogievskiy 6 years, 3 months ago
If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and than propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatel, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit (together with its neighbors) was generated by

for f in $(git grep -l errp \*.[ch]); do \
    spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
    --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
done;

then fix a bit of compilation problems: coccinelle for some reason
leaves several
f() {
    ...
    goto out;
    ...
    out:
}
patterns, with "out:" at function end.

then
./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 net/slirp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/net/slirp.c b/net/slirp.c
index c4334ee876..cbde9ba2a9 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -941,6 +941,7 @@ static ssize_t guestfwd_write(const void *buf, size_t len, void *chr)
 
 static int slirp_guestfwd(SlirpState *s, const char *config_str, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     /* TODO: IPv6 */
     struct in_addr server = { .s_addr = 0 };
     struct GuestFwd *fwd;
@@ -979,7 +980,6 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str, Error **errp)
             return -1;
         }
     } else {
-        Error *err = NULL;
         /*
          * FIXME: sure we want to support implicit
          * muxed monitors here?
@@ -993,9 +993,8 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str, Error **errp)
         }
 
         fwd = g_new(struct GuestFwd, 1);
-        qemu_chr_fe_init(&fwd->hd, chr, &err);
-        if (err) {
-            error_propagate(errp, err);
+        qemu_chr_fe_init(&fwd->hd, chr, errp);
+        if (*errp) {
             object_unparent(OBJECT(chr));
             g_free(fwd);
             return -1;
-- 
2.21.0


Re: [RFC v5 084/126] SLIRP: introduce ERRP_AUTO_PROPAGATE
Posted by Philippe Mathieu-Daudé 6 years, 3 months ago
On 10/11/19 6:05 PM, Vladimir Sementsov-Ogievskiy wrote:
> If we want to add some info to errp (by error_prepend() or
> error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
> Otherwise, this info will not be added when errp == &fatal_err
> (the program will exit prior to the error_append_hint() or
> error_prepend() call).  Fix such cases.
> 
> If we want to check error after errp-function call, we need to
> introduce local_err and than propagate it to errp. Instead, use
> ERRP_AUTO_PROPAGATE macro, benefits are:
> 1. No need of explicit error_propagate call
> 2. No need of explicit local_err variable: use errp directly
> 3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
>     &error_fatel, this means that we don't break error_abort
>     (we'll abort on error_set, not on error_propagate)
> 
> This commit (together with its neighbors) was generated by
> 
> for f in $(git grep -l errp \*.[ch]); do \
>      spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>      --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
> done;
> 
> then fix a bit of compilation problems: coccinelle for some reason
> leaves several
> f() {
>      ...
>      goto out;
>      ...
>      out:
> }
> patterns, with "out:" at function end.
> 
> then
> ./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"
> 
> (auto-msg was a file with this commit message)
> 
> Still, for backporting it may be more comfortable to use only the first
> command and then do one huge commit.
> 
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Reported-by: Greg Kurz <groug@kaod.org>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>   net/slirp.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/net/slirp.c b/net/slirp.c
> index c4334ee876..cbde9ba2a9 100644
> --- a/net/slirp.c
> +++ b/net/slirp.c
> @@ -941,6 +941,7 @@ static ssize_t guestfwd_write(const void *buf, size_t len, void *chr)
>   
>   static int slirp_guestfwd(SlirpState *s, const char *config_str, Error **errp)
>   {
> +    ERRP_AUTO_PROPAGATE();
>       /* TODO: IPv6 */
>       struct in_addr server = { .s_addr = 0 };
>       struct GuestFwd *fwd;
> @@ -979,7 +980,6 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str, Error **errp)
>               return -1;
>           }
>       } else {
> -        Error *err = NULL;
>           /*
>            * FIXME: sure we want to support implicit
>            * muxed monitors here?
> @@ -993,9 +993,8 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str, Error **errp)
>           }
>   
>           fwd = g_new(struct GuestFwd, 1);
> -        qemu_chr_fe_init(&fwd->hd, chr, &err);
> -        if (err) {
> -            error_propagate(errp, err);
> +        qemu_chr_fe_init(&fwd->hd, chr, errp);
> +        if (*errp) {
>               object_unparent(OBJECT(chr));
>               g_free(fwd);
>               return -1;
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>