On Wed, Jan 17, 2018 at 10:39:01AM -0600, Eric DeVolder wrote:
> When kexec is utilized in a Xen environment, it has an explicit
> run-time dependency on libxenctrl.so. This dependency occurs
> during the configure stage and when building kexec-tools.
[...]
As I saw Simon applied the patch. Great! Sadly I have just
realized that I have missed two things. Please look below.
> The patch creates a wrapper function around xc_interface_open()
> and xc_interface_close() to perform the dlopen() and dlclose().
You say about dlclose() here...
diff --git a/kexec/kexec-xen.h b/kexec/kexec-xen.h
new file mode 100644
index 0000000..ffb8743
--- /dev/null
+++ b/kexec/kexec-xen.h
[...]
> +/* The handle from dlopen(), needed by dlsym(), dlclose() */
> +extern void *xc_dlhandle;
...and here but it is never called. Is it by design or by mistake?
If by design please add a comment saying why into relevant place,
e.g. __xc_interface_close()? If by mistake please fix it.
[...]
> +/* The handle from dlopen(), needed by dlsym(), dlclose() */
> +extern void *xc_dlhandle;
I am still not happy with xc_dlhandle being extern. IMO it should be static.
I have missed that during last review. Sorry about that. I have a feeling
that you can easily fix it.
Define __xc_dlsym() in kexec/kexec-xen.c just before __xc_interface_open() like below:
void *__xc_dlsym(const char *symbol)
{
return dlsym(xc_dlhandle, symbol);
}
> +/* Wrappers around xc_interface_open/close() to insert dlopen/dlclose() */
> +xc_interface *__xc_interface_open(xentoollog_logger *logger,
> + xentoollog_logger *dombuild_logger,
> + unsigned open_flags);
> +int __xc_interface_close(xc_interface *xch);
> +
> +/* GCC expression statements for evaluating dlsym() */
> +#define __xc_call(dtype, name, args...) \
> +( \
> + { dtype value; \
> + typedef dtype (*func_t)(xc_interface *, ...); \
> + func_t func = dlsym(xc_dlhandle, #name); \
And then replace dlsym(xc_dlhandle, #name) with __xc_dlsym(#name)...
> + value = func(args); \
> + value; } \
> +)
> +#define __xc_data(dtype, name) \
> +( \
> + { dtype *value = (dtype *)dlsym(xc_dlhandle, #name); value; } \
...and here. Additionally, you can use __xc_dlsym() instead of dlsym()
in other places in your patch. Latter is not a must...
Daniel
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