debuginfod: Add --disable-libdebuginfod and --enable-libdebuginfod=dummy.

Make it possible to build just the debuginfod client or to create a
dummy libdebuginfod that doesn't link against libcurl. The dummy library
can be used for bootstrapping. For testing purposes you can also build
debuginfod against the dummy libdebuginfod but then the debuginfod
server will not be able to do delegation.

Signed-off-by: Mark Wielaard <mark@klomp.org>

3 files changed, 73 insertions, 4 deletions

diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog
index 2bbd5db5..372173e7 100644
--- a/debuginfod/ChangeLog
+++ b/debuginfod/ChangeLog
@@ -1,3 +1,20 @@
+2020-06-19  Mark Wielaard  <mark@klomp.org>
+
+	* Makefile.am (bin_PROGRAMS): Guard with DEBUGINFOD and
+	LIBDEBUGINFOD.
+	(debuginfod_LDADD): Remove libcurl.
+	(libdebuginfod): When static and DUMMY_LIBDEBUGINFO remove libcurl.
+	(noinst_LIBRARIES): Guard with LIBDEBUGINFOD.
+	(AM_CPPFLAGS): Add -Wno-unused-parameter when DUMMY_LIBDEBUGINFOD.
+	(pkginclude_headers): Guard with LIBDEBUGINFOD
+	(libdebuginfod_so_LIBS): Likewise.
+	(+libdebuginfod_so_LDLIBS): Likewise.
+	(install): Likewise.
+	(uninstall): Likewise.
+	* debuginfod-client.c: Include dummy functions when
+	DUMMY_LIBDEBUGINFOD.
+	* debuginfod.cxx: Remove curl.h include.
+
 2020-06-16  Mark Wielaard  <mark@klomp.org>
 
 	* debuginfod-client.c (debuginfod_query_server): Check malloc.
diff --git a/debuginfod/Makefile.am b/debuginfod/Makefile.am
index 51965f65..2e8a343c 100644
--- a/debuginfod/Makefile.am
+++ b/debuginfod/Makefile.am
@@ -45,8 +45,12 @@ if BUILD_STATIC
 libasm = ../libasm/libasm.a
 libdw = ../libdw/libdw.a -lz $(zip_LIBS) $(libelf) $(libebl) -ldl -lpthread
 libelf = ../libelf/libelf.a -lz
+if DUMMY_LIBDEBUGINFOD
 libdebuginfod = ./libdebuginfod.a $(libcurl_LIBS)
 else
+libdebuginfod = ./libdebuginfod.a
+endif
+else
 libasm = ../libasm/libasm.so
 libdw = ../libdw/libdw.so
 libelf = ../libelf/libelf.so
@@ -57,24 +61,45 @@ libeu = ../lib/libeu.a
 
 AM_LDFLAGS = -Wl,-rpath-link,../libelf:../libdw:.
 
-bin_PROGRAMS = debuginfod debuginfod-find
+bin_PROGRAMS =
+if DEBUGINFOD
+bin_PROGRAMS += debuginfod
+endif
+
+if LIBDEBUGINFOD
+bin_PROGRAMS += debuginfod-find
+endif
+
 debuginfod_SOURCES = debuginfod.cxx
-debuginfod_LDADD = $(libdw) $(libelf) $(libeu) $(libdebuginfod) $(libmicrohttpd_LIBS) $(libcurl_LIBS) $(sqlite3_LIBS) $(libarchive_LIBS) -lpthread -ldl
+debuginfod_LDADD = $(libdw) $(libelf) $(libeu) $(libdebuginfod) $(libmicrohttpd_LIBS) $(sqlite3_LIBS) $(libarchive_LIBS) -lpthread -ldl
 
 debuginfod_find_SOURCES = debuginfod-find.c
 debuginfod_find_LDADD = $(libdw) $(libelf) $(libeu) $(libdebuginfod)
 
+if LIBDEBUGINFOD
 noinst_LIBRARIES = libdebuginfod.a
 noinst_LIBRARIES += libdebuginfod_pic.a
+endif
 
 libdebuginfod_a_SOURCES = debuginfod-client.c
 libdebuginfod_pic_a_SOURCES = debuginfod-client.c
 am_libdebuginfod_pic_a_OBJECTS = $(libdebuginfod_a_SOURCES:.c=.os)
 
+if DUMMY_LIBDEBUGINFOD
+AM_CPPFLAGS += -Wno-unused-parameter
+endif
+
+if LIBDEBUGINFOD
 pkginclude_HEADERS = debuginfod.h
+endif
 
+if LIBDEBUGINFOD
 libdebuginfod_so_LIBS = libdebuginfod_pic.a
+if DUMMY_LIBDEBUGINFOD
+libdebuginfod_so_LDLIBS =
+else
 libdebuginfod_so_LDLIBS = $(libcurl_LIBS)
+endif
 libdebuginfod.so$(EXEEXT): $(srcdir)/libdebuginfod.map $(libdebuginfod_so_LIBS)
 	$(AM_V_CCLD)$(LINK) $(dso_LDFLAGS) -o $@ \
 		-Wl,--soname,$@.$(VERSION) \
@@ -83,7 +108,9 @@ libdebuginfod.so$(EXEEXT): $(srcdir)/libdebuginfod.map $(libdebuginfod_so_LIBS)
 		$(libdebuginfod_so_LDLIBS)
 	@$(textrel_check)
 	$(AM_V_at)ln -fs $@ $@.$(VERSION)
+endif
 
+if LIBDEBUGINFOD
 install: install-am libdebuginfod.so
 	$(mkinstalldirs) $(DESTDIR)$(libdir)
 	$(INSTALL_PROGRAM) libdebuginfod.so $(DESTDIR)$(libdir)/libdebuginfod-$(PACKAGE_VERSION).so
@@ -95,6 +122,7 @@ uninstall: uninstall-am
 	rm -f $(DESTDIR)$(libdir)/libdebuginfod.so.$(VERSION)
 	rm -f $(DESTDIR)$(libdir)/libdebuginfod.so
 	rmdir --ignore-fail-on-non-empty $(DESTDIR)$(includedir)/elfutils
+endif
 
 EXTRA_DIST = libdebuginfod.map
 MOSTLYCLEANFILES = $(am_libdebuginfod_pic_a_OBJECTS) libdebuginfod.so.$(VERSION)
diff --git a/debuginfod/debuginfod-client.c b/debuginfod/debuginfod-client.c
index c2aa4e10..c2e43f74 100644
--- a/debuginfod/debuginfod-client.c
+++ b/debuginfod/debuginfod-client.c
@@ -41,13 +41,35 @@
 #include "config.h"
 #include "debuginfod.h"
 #include "system.h"
+#include <errno.h>
+#include <stdlib.h>
+
+/* We might be building a bootstrap dummy library, which is really simple. */
+#ifdef DUMMY_LIBDEBUGINFOD
+
+debuginfod_client *debuginfod_begin (void) { errno = ENOSYS; return NULL; }
+int debuginfod_find_debuginfo (debuginfod_client *c, const unsigned char *b,
+                               int s, char **p) { return -ENOSYS; }
+int debuginfod_find_executable (debuginfod_client *c, const unsigned char *b,
+                                int s, char **p) { return -ENOSYS; }
+int debuginfod_find_source (debuginfod_client *c, const unsigned char *b,
+                            int s, const char *f, char **p)  { return -ENOSYS; }
+void debuginfod_set_progressfn(debuginfod_client *c,
+			       debuginfod_progressfn_t fn) { }
+void debuginfod_set_user_data (debuginfod_client *c, void *d) { }
+void* debuginfod_get_user_data (debuginfod_client *c) { return NULL; }
+const char* debuginfod_get_url (debuginfod_client *c) { return NULL; }
+int debuginfod_add_http_header (debuginfod_client *c,
+				const char *h) { return -ENOSYS; }
+void debuginfod_end (debuginfod_client *c) { }
+
+#else /* DUMMY_LIBDEBUGINFOD */
+
 #include <assert.h>
 #include <dirent.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <errno.h>
 #include <unistd.h>
-#include <errno.h>
 #include <fcntl.h>
 #include <fts.h>
 #include <regex.h>
@@ -1090,3 +1112,5 @@ __attribute__((destructor)) attribute_hidden void libdebuginfod_dtor(void)
   /* ... so don't do this: */
   /* curl_global_cleanup(); */
 }
+
+#endif /* DUMMY_LIBDEBUGINFOD */