Re: [Libguestfs] [PATCH nbdkit 5/9 patch split 1/5] Create libnbdkit.so.

Currently it does nothing.

--- configure.ac | 1 + Makefile.am | 1 + lib/Makefile.am | 71 ++++++++++++++++++++++++++++++++++++++++++++++ server/Makefile.am | 3 ++ server/internal.h | 1 + lib/lib.h | 48 +++++++++++++++++++++++++++++++ lib/init.c | 53 ++++++++++++++++++++++++++++++++++ wrapper.c | 18 ++++++++---- lib/libnbdkit.syms | 47 ++++++++++++++++++++++++++++++ 9 files changed, 237 insertions(+), 6 deletions(-)

+++ b/lib/Makefile.am @@ -0,0 +1,71 @@

+EXTRA_DIST = libnbdkit.syms + +# Note this library always has soname “libnbdkit.so.0” because plugins +# which may link to this library must forever have a stable soname. +# However the library only works with the corresponding nbdkit server +# binary compiled at the same time. The two must be shipped together. + +lib_LTLIBRARIES = libnbdkit.la +libnbdkit_la_SOURCES = \ + init.c \ + lib.h \ + $(NULL) + +libnbdkit_la_CPPFLAGS = \ + -I$(top_srcdir)/include \ + -I$(top_srcdir)/common/include \ + -I$(top_srcdir)/common/utils \ + -DIN_NBDKIT_LIB=1 \ + $(NULL) +libnbdkit_la_CFLAGS = \ + $(PTHREAD_CFLAGS) \ + $(WARNINGS_CFLAGS) \ + $(NULL) +libnbdkit_la_LDFLAGS = \ + $(PTHREAD_LIBS) \ + $(NULL) +libnbdkit_la_LIBADD = \ + $(top_builddir)/common/utils/libutils.la \ + $(NULL) + +if USE_LINKER_SCRIPT_FOR_SERVER +# We have to disable the linker script for libFuzzer because Clang +# adds loads of fuzzer and ASAN-related symbols that are required by +# the plugins but which our linker script tries to hide. +if !ENABLE_LIBFUZZER +libnbdkit_la_LDFLAGS += -Wl,--version-script=$(srcdir)/libnbdkit.syms +endif

+endif

diff --git a/server/Makefile.am b/server/Makefile.am index 4c789934..ad0de9b1 100644 --- a/server/Makefile.am +++ b/server/Makefile.am @@ -80,6 +80,7 @@ nbdkit_CPPFLAGS = \ -Dfilterdir=\"$(filterdir)\" \ -Dsbindir=\"$(sbindir)\" \ -Dsysconfdir=\"$(sysconfdir)\" \ + -I$(top_srcdir)/lib \ -I$(top_srcdir)/include \ -I$(top_srcdir)/common/include \ -I$(top_srcdir)/common/protocol \ @@ -93,6 +94,7 @@ nbdkit_CFLAGS = \ $(VALGRIND_CFLAGS) \ $(NULL) nbdkit_LDADD = \ + ../lib/libnbdkit.la \

+++ b/lib/lib.h @@ -0,0 +1,48 @@

+#ifndef NBDKIT_LIB_H +#define NBDKIT_LIB_H + +#include <stdarg.h> +#include <stdbool.h> +#include <sys/types.h> +#include <sys/socket.h> + +/* Defines the private function which is used by the server to + * initialize libnbdkit.so at runtime. This ABI may change at any + * time, which is why nbdkit and the corresponding libnbdkit.so must + * always be shipped together. + */ +extern void libnbdkit_private_init (const char *expected_version); +

+#endif /* NBDKIT_LIB_H */ diff --git a/lib/init.c b/lib/init.c

+void +libnbdkit_private_init (const char *expected_version) +{ + if (strcmp (expected_version, PACKAGE_VERSION) != 0) { + fprintf (stderr, + "packaging error: " + "nbdkit and libnbdkit.so versions do not match\n"); + abort ();

+ } +} diff --git a/wrapper.c b/wrapper.c index 6aef81a1..eb0ba8ba 100644 --- a/wrapper.c +++ b/wrapper.c

@@ -193,7 +199,7 @@ main (int argc, char *argv[]) free (s); /* Absolute path of the real nbdkit command. */ - passthru_format ("%s/server/nbdkit", builddir); + passthru_format ("%s/server/.libs/nbdkit", builddir);

+++ b/lib/libnbdkit.syms

+ +# This linker script controls the visibility of symbols in the +# libnbdkit.so library. We want to export some symbols to plugins, +# but at the same time we don't want plugins to be able to call +# arbitrary functions from nbdkit, so this script lists only the +# symbols we want to export. + +{ + # The functions we want plugins and filters to call. + global: + + # Private function that must only be called by the server. + libnbdkit_private_init; + + # Everything else is hidden. + local: *; +};