Re: [libvirt] [PATCH] driver: conditionalize use of dlopen functions & use mingw-dlfcn

On Wed, Aug 02, 2017 at 11:26:06 +0100, Daniel Berrange wrote: > Not every platform is guaranteed to have dlopen/dlsym, so we should > conditionalize its use. Suprisingly it is actually present for Win32 > via the mingw-dlfcn add on, but we should still conditionalize it. > > Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; > --- > configure.ac | 2 +- > mingw-libvirt.spec.in | 2 ++ > src/driver.c | 18 ++++++++++++++++-- > 3 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/configure.ac b/configure.ac > index b12b7fae1..2b3375138 100644 > --- a/configure.ac > +++ b/configure.ac > @@ -328,7 +328,7 @@ dnl Availability of various common headers (non-fatal if missing). > AC_CHECK_HEADERS([pwd.h regex.h sys/un.h \ > sys/poll.h syslog.h mntent.h net/ethernet.h linux/magic.h \ > sys/un.h sys/syscall.h sys/sysctl.h netinet/tcp.h ifaddrs.h \ > - libtasn1.h sys/ucred.h sys/mount.h stdarg.h]) > + libtasn1.h sys/ucred.h sys/mount.h stdarg.h dlfcn.h]) A similar check is done in m4/virt-dlopen.m4: AC_CHECK_HEADER([dlfcn.h],, [with_dlfcn=no]) Is it not enough? We already use HAVE_DLFCN_H in few places.

> dnl Check whether endian provides handy macros. > AC_CHECK_DECLS([htole64], [], [], [[#include <endian.h>]]) > AC_CHECK_FUNCS([stat stat64 __xstat __xstat64 lstat lstat64 __lxstat __lxstat64]) > diff --git a/mingw-libvirt.spec.in b/mingw-libvirt.spec.in > index 553d14022..dcb0837f7 100644 > --- a/mingw-libvirt.spec.in > +++ b/mingw-libvirt.spec.in > @@ -54,6 +54,8 @@ BuildRequires: mingw32-libxml2 > BuildRequires: mingw64-libxml2 > BuildRequires: mingw32-portablexdr > BuildRequires: mingw64-portablexdr > +BuildRequires: mingw32-dlfcn > +BuildRequires: mingw64-dlfcn > > BuildRequires: pkgconfig > # Need native version for msgfmt > diff --git a/src/driver.c b/src/driver.c > index 2e7dd01df..04dd0a443 100644 > --- a/src/driver.c > +++ b/src/driver.c > @@ -34,10 +34,11 @@ VIR_LOG_INIT("driver"); > > > /* XXX re-implement this for other OS, or use libtools helper lib ? */ > - > -#include <dlfcn.h> > #define DEFAULT_DRIVER_DIR LIBDIR "/libvirt/connection-driver" > > +#ifdef HAVE_DLFCN_H > +# include <dlfcn.h> > + > > static void * > virDriverLoadModuleFile(const char *file) > @@ -126,6 +127,19 @@ virDriverLoadModuleFull(const char *path, > return ret; > } > > +#else /* ! HAVE_DLFCN_H */ > +int > +virDriverLoadModuleFull(const char *path ATTRIBUTE_UNUSED, > + const char *regfunc ATTRIBUTE_UNUSED, > + void **handle) > +{ > + VIR_DEBUG("dlopen not available on this platform"); > + if (handle) > + *handle = NULL; > + return -1; > +} > +#endif /* ! HAVE_DLFCN_H */ ACK