Add dbus-announce plugin

The plugin announces start and end of transactions

doc/Makefile.am

@@ -21,6 +21,7 @@ man_man8_DATA += rpm-plugin-audit.8
 endif
 if DBUS
 man_man8_DATA += rpm-plugin-systemd-inhibit.8
+man_man8_DATA += rpm-plugin-dbus-announce.8
 endif
 if IMA
 man_man8_DATA += rpm-plugin-ima.8

doc/rpm-plugin-dbus-announce.8

@@ -0,0 +1,26 @@
+'\" t
+.TH "RPM-DBUS-ANNOUNCE" "8" "03 Jun 2020" "Red Hat, Inc."
+.SH NAME
+rpm-plugin-dbus-announce \- DBus plugin for the RPM Package Manager
+
+.SH Description
+
+The plugin writes basic information about rpm transactions to the
+system dbus - like packages installed or removed. Other programms can
+subscribe to the signals to be notified of the packages on the system
+change.
+
+.SH DBus Signals
+
+Sends \fBStartTransaction\fP and \fBEndTransaction\fP messages from the
+\fB/org/rpm/Transaction\fP object with the \fBorg.rpm.Transaction\fP interface.
+
+.SH Configuration
+
+There are currently no options for this plugin in particular. See
+.BR rpm-plugins (8)
+on how to control plugins in general.
+
+.SH SEE ALSO
+.IR dbus-monitor (1)
+.IR rpm-plugins (8)

macros.in

@@ -1183,6 +1183,7 @@ package or when debugging this package.\
 %__transaction_fsverity		%{__plugindir}/fsverity.so
 %__transaction_prioreset	%{__plugindir}/prioreset.so
 %__transaction_audit		%{__plugindir}/audit.so
+%__transaction_dbus_announce	%{__plugindir}/dbus_announce.so
 
 #------------------------------------------------------------------------------
 # Macros for further automated spec %setup and patch application

plugins/Makefile.am

@@ -27,6 +27,14 @@ systemd_inhibit_la_SOURCES = systemd_inhibit.c
 systemd_inhibit_la_CPPFLAGS = $(AM_CPPFLAGS) @DBUS_CFLAGS@
 systemd_inhibit_la_LIBADD = $(top_builddir)/lib/librpm.la $(top_builddir)/rpmio/librpmio.la @DBUS_LIBS@
 plugins_LTLIBRARIES += systemd_inhibit.la
+
+dbus_announce_la_SOURCES = dbus_announce.c
+dbus_announce_la_CPPFLAGS = $(AM_CPPFLAGS) @DBUS_CFLAGS@
+dbus_announce_la_LIBADD = $(top_builddir)/lib/librpm.la $(top_builddir)/rpmio/librpmio.la @DBUS_LIBS@
+plugins_LTLIBRARIES += dbus_announce.la
+
+dbus_confdir=$(sysconfdir)/dbus-1/system.d/
+dbus_conf_DATA = org.rpm.conf
 endif
 
 prioreset_la_SOURCES = prioreset.c

plugins/dbus_announce.c

@@ -0,0 +1,143 @@
+#include "system.h"
+
+#include <dbus/dbus.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <rpm/rpmlog.h>
+#include <rpm/rpmts.h>
+#include <rpm/rpmdb.h>
+#include "lib/rpmplugin.h"
+
+struct dbus_announce_data {
+    DBusConnection * bus;
+    int logging;
+    int old_dboffset;
+};
+
+static rpmRC dbus_announce_init(rpmPlugin plugin, rpmts ts)
+{
+    struct dbus_announce_data * state = rcalloc(1, sizeof(*state));
+    rpmPluginSetData(plugin, state);
+    return RPMRC_OK;
+}
+
+static rpmRC open_dbus(rpmPlugin plugin, rpmts ts)
+{
+    struct stat st;
+    DBusError err;
+    int rc = 0;
+    struct dbus_announce_data * state = rpmPluginGetData(plugin);
+
+    /* Assume we are logging but... */
+    state->logging = 1;
+
+    /* ...don't log test transactions */
+    if (rpmtsFlags(ts) & (RPMTRANS_FLAG_TEST|RPMTRANS_FLAG_BUILD_PROBS))
+	state->logging = 0;
+
+    /* ...don't log chroot transactions */
+    if (!rstreq(rpmtsRootDir(ts), "/"))
+	state->logging = 0;
+
+    /* Don't open */
+    if (!state->logging || state->bus)
+	return RPMRC_OK;
+
+    if (lstat("/run/systemd/system/", &st) == 0) {
+        if (S_ISDIR(st.st_mode)) {
+	    // initialise the error value
+	    dbus_error_init(&err);
+
+	    state->bus = dbus_bus_get_private(DBUS_BUS_SYSTEM, &err);
+	    if (dbus_error_is_set(&err)) {
+		fprintf(stderr, "Connection Error (%s)\n", err.message);
+		dbus_error_free(&err);
+	    }
+	    if (state->bus) {
+		rc = dbus_bus_request_name(state->bus, "org.rpm.announce",
+				  DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
+	    }
+	    if (dbus_error_is_set(&err)) {
+		//fprintf(stderr, "Name Error (%s)\n", err.message);
+		dbus_error_free(&err);
+	    }
+	    if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != rc) {
+		dbus_connection_close(state->bus);
+		dbus_connection_unref(state->bus);
+		state->bus = NULL;
+		state->logging = 0;
+		return RPMRC_NOTFOUND;
+	    }
+            return RPMRC_OK;
+        }
+    }
+
+    return RPMRC_NOTFOUND;
+}
+
+static void dbus_announce_cleanup(rpmPlugin plugin)
+{
+    struct dbus_announce_data * state = rpmPluginGetData(plugin);
+    if (state->bus) {
+	dbus_connection_close(state->bus);
+	dbus_connection_unref(state->bus);
+    }
+    free(state);
+}
+
+static rpmRC send_ts_message(rpmPlugin plugin,
+			     const char * name,
+			     rpmts ts,
+			     int res)
+{
+    struct dbus_announce_data * state = rpmPluginGetData(plugin);
+    DBusMessage* msg;
+    dbus_uint32_t serial = 0;
+    char * dbcookie;
+
+    if (!state->logging) {
+	return RPMRC_OK;
+    }
+
+    msg = dbus_message_new_signal("/org/rpm/Transaction", // object name
+				  "org.rpm.Transaction", // interface name
+				  name); // name of the signal
+    if (NULL == msg) {
+	return RPMRC_FAIL;
+    }
+
+    dbcookie = rpmdbCookie(rpmtsGetRdb(ts));
+    if (!dbus_message_append_args(msg, DBUS_TYPE_STRING, &dbcookie)) {
+	return RPMRC_FAIL;
+    }
+    dbcookie = _free(dbcookie);
+
+    if (!dbus_connection_send(state->bus, msg, &serial)) {
+	return RPMRC_FAIL;
+    }
+    dbus_connection_flush(state->bus);
+    return RPMRC_OK;
+}
+
+static rpmRC dbus_announce_tsm_pre(rpmPlugin plugin, rpmts ts)
+{
+    int rc;
+
+    rc = open_dbus(plugin, ts);
+    if (rc != RPMRC_OK)
+	return rc;
+    return send_ts_message(plugin, "StartTransaction", ts, RPMRC_OK);
+}
+
+static rpmRC dbus_announce_tsm_post(rpmPlugin plugin, rpmts ts, int res)
+{
+    return send_ts_message(plugin, "EndTransaction", ts, res);
+}
+
+struct rpmPluginHooks_s dbus_announce_hooks = {
+    .init = dbus_announce_init,
+    .cleanup = dbus_announce_cleanup,
+    .tsm_pre = dbus_announce_tsm_pre,
+    .tsm_post = dbus_announce_tsm_post,
+};

plugins/org.rpm.conf

@@ -0,0 +1,10 @@
+<!DOCTYPE busconfig PUBLIC
+          "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
+          "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig>
+
+<policy user="root">
+  <allow own="org.rpm.announce"/>
+</policy>
+
+</busconfig>