[PATCH] Avoid dlopen on debuginfod-client when not configured
Mark Wielaard
mark@klomp.org
Tue Mar 29 07:42:02 GMT 2022
Hi Dirk,
On Mon, Mar 28, 2022 at 11:36:41PM +0200, Dirk Müller wrote:
> Loading debuginfod-client is expensive, especially when
> FIPS is enabled, as it goes through time intensive self-checks
> on load.
I assume this is because debuginfod-client loads and initializes
libcurl, which triggers crypto checks for https support?
> Avoid dlopen() when no debuginfo url is set.
The patch itself looks right. But I am slightly afraid this
(theoretically?) will break some programs which set DEBUGINFOD_URLS
themselves. We currently have no other way to make libdwfl use
debuginfod-client. Thoughts?
Cheers,
Mark
> Signed-off-by: Dirk Müller <dirk@dmllr.de>
> ---
> libdwfl/ChangeLog | 5 +++++
> libdwfl/debuginfod-client.c | 12 +++++++++++-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
> index 9c5c8517..1ec13f30 100644
> --- a/libdwfl/ChangeLog
> +++ b/libdwfl/ChangeLog
> @@ -1,3 +1,8 @@
> +2022-03-28 Dirk Müller <dirk@dmllr.de>
> +
> + * debuginfod-client.c (__libdwfl_debuginfod_init): Skip dlopen
> + if debuginfod url is unset.
> +
> 2022-02-18 Mark Wielaard <mark@klomp.org>
>
> * image-header.c (__libdw_image_header): Assign header values for
> diff --git a/libdwfl/debuginfod-client.c b/libdwfl/debuginfod-client.c
> index 99b66b6e..af9d1363 100644
> --- a/libdwfl/debuginfod-client.c
> +++ b/libdwfl/debuginfod-client.c
> @@ -101,7 +101,17 @@ __libdwfl_debuginfod_end (debuginfod_client *c)
> void __attribute__ ((constructor))
> __libdwfl_debuginfod_init (void)
> {
> - void *debuginfod_so = dlopen(DEBUGINFOD_SONAME, RTLD_LAZY);
> + void *debuginfod_so;
> +
> + /* Is there any server we can query? If not, don't do any work,
> + just return with ENOSYS. Don't even access the cache. */
> + char *urls_envvar = getenv(DEBUGINFOD_URLS_ENV_VAR);
> + if (urls_envvar == NULL || urls_envvar[0] == '\0')
> + {
> + return;
> + }
> +
> + debuginfod_so = dlopen(DEBUGINFOD_SONAME, RTLD_LAZY);
>
> if (debuginfod_so != NULL)
> {
> --
> 2.35.1
>
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