From 7bfd1238ce3a1e122821e0dffb3d3f5db1370f05 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Tue, 14 Jun 2005 19:06:26 +0000
Subject: [PATCH] Fixing some makesfiles, so that the correct things link
 against pthreads. Also changed dmevent so that in no longer links against
 pthreads, and dynamically loads libdmevent.so.  Everything seems to work just
 fine like this.

---
 daemons/dmeventd/Makefile.in |  6 ++--
 daemons/dmeventd/dmevent.c   | 60 +++++++++++++++++++++++++++++++-----
 2 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/daemons/dmeventd/Makefile.in b/daemons/dmeventd/Makefile.in
index ddacbbed3..394f61e52 100644
--- a/daemons/dmeventd/Makefile.in
+++ b/daemons/dmeventd/Makefile.in
@@ -28,7 +28,7 @@ else
   LIB_SHARED = libdmeventdnoop.so
 endif
  
-LDFLAGS += -ldl -ldevmapper -lpthread -lmultilog
+LDFLAGS += -ldl -ldevmapper -lmultilog
 
 include ../make.tmpl
 
@@ -36,11 +36,11 @@ libdmeventdnoop.so: noop.o
 
 dmevent: dmevent.o $(interfacedir)/libdevmapper.$(LIB_SUFFIX) $(top_srcdir)/lib/event/libdmevent.$(LIB_SUFFIX)
 	$(CC) -o $@ dmevent.o $(LDFLAGS) \
-	      -L$(interfacedir) -L$(DESTDIR)/lib -L$(top_srcdir)/lib/event -L$(top_srcdir)/multilog -ldmevent $(LIBS)
+	      -L$(interfacedir) -L$(DESTDIR)/lib -L$(top_srcdir)/lib/event -L$(top_srcdir)/multilog $(LIBS)
 
 dmeventd: dmeventd.o $(interfacedir)/libdevmapper.$(LIB_SUFFIX) $(top_srcdir)/lib/event/libdmevent.$(LIB_SUFFIX)
 	$(CC) -o $@ dmeventd.o $(LDFLAGS) \
-	      -L$(interfacedir) -L$(DESTDIR)/lib -L$(top_srcdir)/lib/event -L$(top_srcdir)/multilog -ldmevent $(LIBS)
+	      -L$(interfacedir) -L$(DESTDIR)/lib -L$(top_srcdir)/lib/event -L$(top_srcdir)/multilog -lpthread -ldmevent $(LIBS)
 
 install: $(INSTALL_TYPE)
 
diff --git a/daemons/dmeventd/dmevent.c b/daemons/dmeventd/dmevent.c
index 9ea63d6ab..6e9eb4601 100644
--- a/daemons/dmeventd/dmevent.c
+++ b/daemons/dmeventd/dmevent.c
@@ -26,12 +26,24 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <dlfcn.h>
 
 static enum event_type events = ALL_ERRORS; /* All until we can distinguish. */
 static char default_dso_name[] = "noop";  /* default DSO is noop */
 static int default_reg = 1;		 /* default action is register */
 static uint32_t timeout;
 
+struct event_ops {
+int (*dm_register_for_event)(char *dso_name, char *device,
+			     enum event_type event_types);
+int (*dm_unregister_for_event)(char *dso_name, char *device,
+			       enum event_type event_types);
+int (*dm_get_registered_device)(char **dso_name, char **device,
+				enum event_type *event_types, int next);
+int (*dm_set_event_timeout)(char *device, uint32_t time);
+int (*dm_get_event_timeout)(char *device, uint32_t *time);
+};
+
 /* Display help. */
 static void print_usage(char *name)
 {
@@ -102,8 +114,35 @@ static int parse_argv(int argc, char **argv, char **dso_name_arg,
 	return 1;
 }
 
+
+static int lookup_symbol(void *dl, void **symbol, const char *name)
+{
+	if ((*symbol = dlsym(dl, name)))
+		return 1;
+
+	fprintf(stderr, "error looking up %s symbol: %s\n", name, dlerror());
+
+	return 0;
+}
+
+static int lookup_symbols(void *dl, struct event_ops *e)
+{
+	return lookup_symbol(dl, (void *) &e->dm_register_for_event,
+			     "dm_register_for_event") &&
+	       lookup_symbol(dl, (void *) &e->dm_unregister_for_event,
+			     "dm_unregister_for_event") &&
+	       lookup_symbol(dl, (void *) &e->dm_get_registered_device,
+			     "dm_get_registered_device") &&
+	       lookup_symbol(dl, (void *) &e->dm_set_event_timeout,
+			     "dm_set_event_timeout") &&
+	       lookup_symbol(dl, (void *) &e->dm_get_event_timeout,
+			     "dm_get_event_timeout");
+}
+
 int main(int argc, char **argv)
 {
+	void *dl;
+	struct event_ops e;
 	int list = 0, next = 0, ret, reg = default_reg;
 	char *device, *device_arg = NULL, *dso_name, *dso_name_arg = NULL;
 
@@ -128,15 +167,22 @@ int main(int argc, char **argv)
 	multilog_add_type(standard, NULL);
 	multilog_init_verbose(standard, _LOG_DEBUG);
 
+	if (!(dl = dlopen("libdmevent.so", RTLD_NOW))){
+		fprintf(stderr, "Cannot dlopen libdmevent.so: %s\n", dlerror());
+		goto out;
+	}
+	if (!(lookup_symbols(dl, &e)))
+		goto out;
 	if (list) {
 		while (1) {
-			if ((ret= dm_get_registered_device(&dso_name, &device,
-							   &events, next)))
+			if ((ret= e.dm_get_registered_device(&dso_name,
+							     &device,
+							     &events, next)))
 				break;
 			printf("%s %s 0x%x", dso_name, device, events);
 			if (events & TIMEOUT){
-				if ((ret = dm_get_event_timeout(device,
-							  	&timeout))) {
+				if ((ret = e.dm_get_event_timeout(device,
+							  	  &timeout))) {
 					ret = EXIT_FAILURE;
 					goto out;
 				}
@@ -153,14 +199,14 @@ int main(int argc, char **argv)
 		goto out;
 	}
 
-	if ((ret = reg ? dm_register_for_event(dso_name, device, events) :
-			 dm_unregister_for_event(dso_name, device, events))) {
+	if ((ret = reg ? e.dm_register_for_event(dso_name, device, events) :
+			 e.dm_unregister_for_event(dso_name, device, events))) {
 		fprintf(stderr, "Failed to %sregister %s: %s\n",
 			reg ? "": "un", device, strerror(-ret));
 		ret = EXIT_FAILURE;
 	} else {
 		if (reg && (events & TIMEOUT) &&
-		    ((ret = dm_set_event_timeout(device, timeout)))){
+		    ((ret = e.dm_set_event_timeout(device, timeout)))){
 			fprintf(stderr, "Failed to set timeout for %s: %s\n",
 				device, strerror(-ret));
 			ret = EXIT_FAILURE;