tools/nut-scanner/*.c: refactor nutscan_free() to actively lt_dlclose…

…() the loaded library modules [networkupstools#2511]

Avoid some memory leak reports

Signed-off-by: Jim Klimov <[email protected]>

tools/nut-scanner/nut-scanner.c

@@ -1886,8 +1886,8 @@ int main(int argc, char *argv[])
 #endif
 
 	upsdebugx(1, "SCANS DONE: free common scanner resources");
-	nutscan_free();
 	nutscan_free_ip_ranges(&ip_ranges_list);
+	nutscan_free();
 
 	upsdebugx(1, "SCANS DONE: EXIT_SUCCESS");
 	return EXIT_SUCCESS;

tools/nut-scanner/nutscan-init.c

@@ -41,6 +41,11 @@
 # if defined HAVE_WINSOCK2_H && HAVE_WINSOCK2_H
 #  include <winsock2.h>
 # endif
+#endif
+
+/* FIXME: We may want to (also?) use lt_dlopenext(), so
+ * that libtool would offer platform-specific extensions */
+#ifdef WIN32
 # define SOEXT ".dll"
 #else
 # ifdef NUT_PLATFORM_APPLE_OSX
@@ -61,12 +66,19 @@ int nutscan_avail_snmp = 0;
 int nutscan_avail_usb = 0;
 int nutscan_avail_xml_http = 0;
 
+/* Methods defined in scan_*.c source files */
 int nutscan_load_usb_library(const char *libname_path);
+int nutscan_unload_usb_library(void);
 int nutscan_load_snmp_library(const char *libname_path);
+int nutscan_unload_snmp_library(void);
 int nutscan_load_neon_library(const char *libname_path);
+int nutscan_unload_neon_library(void);
 int nutscan_load_avahi_library(const char *libname_path);
+int nutscan_unload_avahi_library(void);
 int nutscan_load_ipmi_library(const char *libname_path);
+int nutscan_unload_ipmi_library(void);
 int nutscan_load_upsclient_library(const char *libname_path);
+int nutscan_unload_upsclient_library(void);
 
 #ifdef HAVE_PTHREAD
 # ifdef HAVE_SEMAPHORE
@@ -586,27 +598,67 @@ void nutscan_init(void)
 	nutscan_avail_nut_simulation = 1;
 }
 
-void nutscan_free(void)
+/* return 0 on success, -1 on error e.g. "was not loaded";
+ * other values may be possible if lt_dlclose() errors set them;
+ * visible externally to scan_* modules */
+int nutscan_unload_library(int *avail, lt_dlhandle *pdl_handle, char **libpath);
+int nutscan_unload_library(int *avail, lt_dlhandle *pdl_handle, char **libpath)
 {
-	if (nutscan_avail_usb) {
-		lt_dlexit();
+	int ret = -1;
+
+	if (avail == NULL || pdl_handle == NULL) {
+		upsdebugx(1, "%s: called with bad inputs, no-op", __func__);
+		return -2;
 	}
-	if (nutscan_avail_snmp) {
-		lt_dlexit();
+
+	/* never tried/already unloaded */
+	if (*pdl_handle == NULL) {
+		goto end;
 	}
-	if (nutscan_avail_xml_http) {
-		lt_dlexit();
+
+	/* if previous init failed */
+	if (*pdl_handle == (void *)1) {
+		goto end;
 	}
-	if (nutscan_avail_avahi) {
-		lt_dlexit();
+
+	if (*avail == 0) {
+		upsdebugx(1, "%s: Asked to unload a module %p "
+			"for %s but our flag says it is not loaded",
+			__func__, (void *)(*pdl_handle),
+			(libpath && *libpath && **libpath)
+			? *libpath
+			: "<unidentified module>");
 	}
-	if (nutscan_avail_ipmi) {
-		lt_dlexit();
+
+	/* init has already been done */
+	if (libpath && *libpath && **libpath) {
+		upsdebugx(1, "%s: unloading module %s",
+			__func__, *libpath);
 	}
-	if (nutscan_avail_nut) {
-		lt_dlexit();
+	ret = lt_dlclose(*pdl_handle);
+	lt_dlexit();
+
+end:
+	*pdl_handle = NULL;
+	*avail = 0;
+
+	if (libpath && *libpath) {
+		free(*libpath);
+		*libpath = NULL;
 	}
 
+	return ret;
+}
+
+void nutscan_free(void)
+{
+	nutscan_unload_usb_library();
+	nutscan_unload_snmp_library();
+	nutscan_unload_neon_library();
+	nutscan_unload_avahi_library();
+	nutscan_unload_ipmi_library();
+	nutscan_unload_upsclient_library();
+
 #ifdef HAVE_PTHREAD
 /* TOTHINK: See comments near mutex/semaphore init code above */
 # ifdef HAVE_SEMAPHORE

tools/nut-scanner/scan_avahi.c

@@ -27,6 +27,9 @@
 #include "common.h"
 #include "nut-scan.h"
 
+/* externally visible to nutscan-init */
+int nutscan_unload_avahi_library(void);
+
 #ifdef WITH_AVAHI
 
 #include <stdio.h>
@@ -48,6 +51,7 @@
 /* dynamic link library stuff */
 static lt_dlhandle dl_handle = NULL;
 static const char *dl_error = NULL;
+static char *dl_saved_libname = NULL;
 
 static AvahiClient* (*nut_avahi_service_browser_get_client)(AvahiServiceBrowser *);
 static int (*nut_avahi_simple_poll_loop)(AvahiSimplePoll *s);
@@ -91,6 +95,15 @@ static int (*nut_avahi_service_browser_free)(AvahiServiceBrowser *);
 static char * (*nut_avahi_address_snprint)(char *ret_s, size_t length, const AvahiAddress *a);
 static const AvahiPoll* (*nut_avahi_simple_poll_get)(AvahiSimplePoll *s);
 
+/* return 0 on success, -1 on error e.g. "was not loaded";
+ * other values may be possible if lt_dlclose() errors set them;
+ * visible externally */
+int nutscan_unload_library(int *avail, lt_dlhandle *pdl_handle, char **libpath);
+int nutscan_unload_avahi_library(void)
+{
+	return nutscan_unload_library(&nutscan_avail_avahi, &dl_handle, &dl_saved_libname);
+}
+
 /* return 0 on error; visible externally */
 int nutscan_load_avahi_library(const char *libname_path);
 int nutscan_load_avahi_library(const char *libname_path)
@@ -210,13 +223,21 @@ int nutscan_load_avahi_library(const char *libname_path)
 		goto err;
 	}
 
+	if (dl_saved_libname)
+		free(dl_saved_libname);
+	dl_saved_libname = xstrdup(libname_path);
+
 	return 1;
 err:
 	fprintf(stderr,
 		"Cannot load AVAHI library (%s) : %s. AVAHI search disabled.\n",
 		libname_path, dl_error);
 	dl_handle = (void *)1;
 	lt_dlexit();
+	if (dl_saved_libname) {
+		free(dl_saved_libname);
+		dl_saved_libname = NULL;
+	}
 	return 0;
 }
 /* end of dynamic link library stuff */
@@ -600,4 +621,8 @@ nutscan_device_t * nutscan_scan_avahi(useconds_t usec_timeout)
 	return NULL;
 }
 
+int nutscan_unload_avahi_library(void)
+{
+	return 0;
+}
 #endif /* WITH_AVAHI */

tools/nut-scanner/scan_ipmi.c

@@ -28,6 +28,9 @@
 #include "nut-scan.h"
 #include "nut_stdint.h"
 
+/* externally visible to nutscan-init */
+int nutscan_unload_ipmi_library(void);
+
 #ifdef WITH_IPMI
 
 #include "upsclient.h"
@@ -46,6 +49,7 @@
 /* dynamic link library stuff */
 static lt_dlhandle dl_handle = NULL;
 static const char *dl_error = NULL;
+static char *dl_saved_libname = NULL;
 
 #ifdef HAVE_FREEIPMI_11X_12X
   /* Functions symbols remapping */
@@ -134,6 +138,15 @@ typedef int bool_t;
 static nutscan_device_t * nutscan_scan_ipmi_device(const char * IPaddr, nutscan_ipmi_t * sec);
 static void * nutscan_scan_ipmi_device_thready(void * arg_sec);
 
+/* return 0 on success, -1 on error e.g. "was not loaded";
+ * other values may be possible if lt_dlclose() errors set them;
+ * visible externally */
+int nutscan_unload_library(int *avail, lt_dlhandle *pdl_handle, char **libpath);
+int nutscan_unload_ipmi_library(void)
+{
+	return nutscan_unload_library(&nutscan_avail_ipmi, &dl_handle, &dl_saved_libname);
+}
+
 /* Return 0 on error; visible externally */
 int nutscan_load_ipmi_library(const char *libname_path);
 int nutscan_load_ipmi_library(const char *libname_path)
@@ -261,6 +274,10 @@ int nutscan_load_ipmi_library(const char *libname_path)
 			goto err;
 	}
 
+	if (dl_saved_libname)
+		free(dl_saved_libname);
+	dl_saved_libname = xstrdup(libname_path);
+
 	return 1;
 
 err:
@@ -269,6 +286,10 @@ int nutscan_load_ipmi_library(const char *libname_path)
 		libname_path, dl_error);
 	dl_handle = (void *)1;
 	lt_dlexit();
+	if (dl_saved_libname) {
+		free(dl_saved_libname);
+		dl_saved_libname = NULL;
+	}
 	return 0;
 }
 /* end of dynamic link library stuff */
@@ -1048,4 +1069,8 @@ nutscan_device_t *  nutscan_scan_ip_range_ipmi(nutscan_ip_range_list_t * irl, nu
 	return NULL;
 }
 
+int nutscan_unload_ipmi_library(void)
+{
+	return 0;
+}
 #endif /* WITH_IPMI */

tools/nut-scanner/scan_nut.c

@@ -37,6 +37,7 @@
 /* dynamic link library stuff */
 static lt_dlhandle dl_handle = NULL;
 static const char *dl_error = NULL;
+static char *dl_saved_libname = NULL;
 
 static int (*nut_upscli_splitaddr)(const char *buf, char **hostname, uint16_t *port);
 static int (*nut_upscli_tryconnect)(UPSCONN_t *ups, const char *host, uint16_t port,
@@ -68,6 +69,16 @@ struct scan_nut_arg {
 	useconds_t timeout;
 };
 
+/* return 0 on success, -1 on error e.g. "was not loaded";
+ * other values may be possible if lt_dlclose() errors set them;
+ * visible externally */
+int nutscan_unload_library(int *avail, lt_dlhandle *pdl_handle, char **libpath);
+int nutscan_unload_upsclient_library(void);
+int nutscan_unload_upsclient_library(void)
+{
+	return nutscan_unload_library(&nutscan_avail_nut, &dl_handle, &dl_saved_libname);
+}
+
 /* return 0 on error; visible externally */
 int nutscan_load_upsclient_library(const char *libname_path);
 int nutscan_load_upsclient_library(const char *libname_path)
@@ -129,6 +140,10 @@ int nutscan_load_upsclient_library(const char *libname_path)
 			goto err;
 	}
 
+	if (dl_saved_libname)
+		free(dl_saved_libname);
+	dl_saved_libname = xstrdup(libname_path);
+
 	return 1;
 
 err:
@@ -137,6 +152,10 @@ int nutscan_load_upsclient_library(const char *libname_path)
 		libname_path, dl_error);
 	dl_handle = (void *)1;
 	lt_dlexit();
+	if (dl_saved_libname) {
+		free(dl_saved_libname);
+		dl_saved_libname = NULL;
+	}
 	return 0;
 }
 /* end of dynamic link library stuff */

tools/nut-scanner/scan_snmp.c

@@ -29,6 +29,9 @@
 #include "nut-scan.h"
 #include "nut_stdint.h"
 
+/* externally visible to nutscan-init */
+int nutscan_unload_snmp_library(void);
+
 #ifdef WITH_SNMP
 
 #ifndef WIN32
@@ -116,6 +119,7 @@ typedef int bool_t;
 /* dynamic link library stuff */
 static lt_dlhandle dl_handle = NULL;
 static const char *dl_error = NULL;
+static char *dl_saved_libname = NULL;
 #endif	/* WITH_SNMP_STATIC */
 
 static void (*nut_init_snmp)(const char *type);
@@ -177,9 +181,23 @@ static oid *nut_usmHMAC256SHA384AuthProtocol;
 static oid *nut_usmHMAC384SHA512AuthProtocol;
 #endif
 
+/* return 0 on success, -1 on error e.g. "was not loaded";
+ * other values may be possible if lt_dlclose() errors set them;
+ * visible externally */
+#ifndef WITH_SNMP_STATIC
+int nutscan_unload_library(int *avail, lt_dlhandle *pdl_handle, char **libpath);
+#endif
+int nutscan_unload_snmp_library(void)
+{
+#ifdef WITH_SNMP_STATIC
+	return 0;
+#else
+	return nutscan_unload_library(&nutscan_avail_snmp, &dl_handle, &dl_saved_libname);
+#endif
+}
+
 /* return 0 on error; visible externally */
 int nutscan_load_snmp_library(const char *libname_path);
-
 int nutscan_load_snmp_library(const char *libname_path)
 {
 #ifdef WITH_SNMP_STATIC
@@ -453,7 +471,11 @@ int nutscan_load_snmp_library(const char *libname_path)
 	}
 #endif /* NUT_HAVE_LIBNETSNMP_usmHMAC384SHA512AuthProtocol */
 
-#endif	/* WITH_SNMP_STATIC */
+	if (dl_saved_libname)
+		free(dl_saved_libname);
+	dl_saved_libname = xstrdup(libname_path);
+
+#endif	/* not WITH_SNMP_STATIC */
 
 	return 1;
 
@@ -464,6 +486,10 @@ int nutscan_load_snmp_library(const char *libname_path)
 		libname_path, dl_error);
 	dl_handle = (void *)1;
 	lt_dlexit();
+	if (dl_saved_libname) {
+		free(dl_saved_libname);
+		dl_saved_libname = NULL;
+	}
 	return 0;
 #endif	/* not WITH_SNMP_STATIC */
 }
@@ -1422,4 +1448,8 @@ nutscan_device_t * nutscan_scan_ip_range_snmp(nutscan_ip_range_list_t * irl,
 	return NULL;
 }
 
+int nutscan_unload_snmp_library(void)
+{
+	return 0;
+}
 #endif /* WITH_SNMP */