Daniel,
I've implemented your feedback and posted the following:
[PATCH v1] kexec-tools: Tweak run-time handling of libxenctrl.so
Regards,
eric
On 01/18/2018 05:55 AM, Daniel Kiper wrote:
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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