bus: add monitoring facility to busctl

src/libsystemd-bus/busctl.c

@@ -19,33 +19,49 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <getopt.h>
+
 #include "strv.h"
 #include "util.h"
 #include "log.h"
+#include "build.h"
+#include "pager.h"
 
 #include "sd-bus.h"
 #include "bus-message.h"
 #include "bus-internal.h"
 
-int main(int argc, char *argv[]) {
-        _cleanup_bus_unref_ sd_bus *bus = NULL;
+static bool arg_no_pager = false;
+static char *arg_address = NULL;
+static bool arg_user = false;
+static bool arg_no_unique = false;
+static char **arg_matches = NULL;
+
+static void pager_open_if_enabled(void) {
+
+        /* Cache result before we open the pager */
+        if (arg_no_pager)
+                return;
+
+        pager_open(false);
+}
+
+static int list_bus_names(sd_bus *bus, char **argv) {
         _cleanup_strv_free_ char **l = NULL;
         char **i;
         int r;
         size_t max_i = 0;
 
-        r = sd_bus_open_user(&bus);
-        if (r < 0) {
-                log_error("Failed to connect to bus: %s", strerror(-r));
-                goto fail;
-        }
+        assert(bus);
 
         r = sd_bus_list_names(bus, &l);
         if (r < 0) {
                 log_error("Failed to list names: %s", strerror(-r));
-                goto fail;
+                return r;
         }
 
+        pager_open_if_enabled();
+
         strv_sort(l);
 
         STRV_FOREACH(i, l)
@@ -59,8 +75,8 @@ int main(int argc, char *argv[]) {
                 pid_t pid;
                 uid_t uid;
 
-                /* if ((*i)[0] == ':') */
-                /*         continue; */
+                if (arg_no_unique && (*i)[0] == ':')
+                        continue;
 
                 printf("%-*s", (int) max_i, *i);
 
@@ -80,10 +96,8 @@ int main(int argc, char *argv[]) {
                         _cleanup_free_ char *u = NULL;
 
                         u = uid_to_name(uid);
-                        if (!u) {
-                                log_oom();
-                                goto fail;
-                        }
+                        if (!u)
+                                return log_oom();
 
                         if (strlen(u) > 16)
                                 u[16] = 0;
@@ -99,8 +113,228 @@ int main(int argc, char *argv[]) {
                         printf(" -\n");
         }
 
-        r = 0;
+        return 0;
+}
+
+static int monitor(sd_bus *bus, char *argv[]) {
+        char **i;
+        int r;
+
+        STRV_FOREACH(i, argv+1) {
+                _cleanup_free_ char *m = NULL;
+
+                if (!service_name_is_valid(*i)) {
+                        log_error("Invalid service name '%s'", *i);
+                        return -EINVAL;
+                }
+
+                m = strjoin("sender='", *i, "'", NULL);
+                if (!m)
+                        return log_oom();
+
+                r = sd_bus_add_match(bus, m, NULL, NULL);
+                if (r < 0) {
+                        log_error("Failed to add match: %s", strerror(-r));
+                        return r;
+                }
+        }
+
+        STRV_FOREACH(i, arg_matches) {
+                r = sd_bus_add_match(bus, *i, NULL, NULL);
+                if (r < 0) {
+                        log_error("Failed to add match: %s", strerror(-r));
+                        return r;
+                }
+        }
+
+        for (;;) {
+                _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+
+                r = sd_bus_process(bus, &m);
+                if (r < 0) {
+                        log_error("Failed to process bus: %s", strerror(-r));
+                        return r;
+                }
+
+                if (m) {
+                        bus_message_dump(m);
+                        continue;
+                }
+
+                if (r > 0)
+                        continue;
+
+                r = sd_bus_wait(bus, (uint64_t) -1);
+                if (r < 0) {
+                        log_error("Failed to wait for bus: %s", strerror(-r));
+                        return r;
+                }
+        }
+
+        return -EINVAL;
+}
+
+static int help(void) {
+
+        printf("%s [OPTIONS...] {COMMAND} ...\n\n"
+               "Introspect the bus.\n\n"
+               "  -h --help              Show this help\n"
+               "     --version           Show package version\n"
+               "     --system            Connect to system bus\n"
+               "     --user              Connect to user bus\n"
+               "     --address=ADDRESS   Connect to bus specified by address\n"
+               "     --no-unique         Only show well-known names\n"
+               "     --match=MATCH       Only show matching messages\n"
+               "     --no-pager          Do not pipe output into a pager\n\n"
+               "Commands:\n"
+               "  list                   List bus names\n"
+               "  monitor [SERVICE...]   Show bus traffic\n",
+               program_invocation_short_name);
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_NO_PAGER,
+                ARG_SYSTEM,
+                ARG_USER,
+                ARG_ADDRESS,
+                ARG_MATCH,
+                ARG_NO_UNIQUE
+        };
+
+        static const struct option options[] = {
+                { "help",      no_argument,       NULL, 'h'           },
+                { "version",   no_argument,       NULL, ARG_VERSION   },
+                { "no-pager",  no_argument,       NULL, ARG_NO_PAGER  },
+                { "system",    no_argument,       NULL, ARG_SYSTEM    },
+                { "user",      no_argument,       NULL, ARG_USER      },
+                { "address",   required_argument, NULL, ARG_ADDRESS   },
+                { "no-unique", no_argument,       NULL, ARG_NO_UNIQUE },
+                { "match",     required_argument, NULL, ARG_MATCH     },
+                { NULL,        0,                 NULL, 0             },
+        };
+
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
+
+                switch (c) {
+
+                case 'h':
+                        return help();
+
+                case ARG_VERSION:
+                        puts(PACKAGE_STRING);
+                        puts(SYSTEMD_FEATURES);
+                        return 0;
+
+                case ARG_NO_PAGER:
+                        arg_no_pager = true;
+                        break;
+
+                case ARG_USER:
+                        arg_user = true;
+                        break;
+
+                case ARG_SYSTEM:
+                        arg_user = false;
+                        break;
+
+                case ARG_ADDRESS:
+                        arg_address = optarg;
+                        break;
+
+                case ARG_NO_UNIQUE:
+                        arg_no_unique = true;
+                        break;
+
+                case ARG_MATCH:
+                        if (strv_extend(&arg_matches, optarg) < 0)
+                                return log_oom();
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        log_error("Unknown option code %c", c);
+                        return -EINVAL;
+                }
+        }
+
+        return 1;
+}
+
+static int busctl_main(sd_bus *bus, int argc, char *argv[]) {
+        assert(bus);
+
+        if (optind >= argc ||
+            streq(argv[optind], "list"))
+                return list_bus_names(bus, argv + optind);
+
+        if (streq(argv[optind], "monitor"))
+                return monitor(bus, argv + optind);
+
+        if (streq(argv[optind], "help"))
+                return help();
+
+        log_error("Unknown command '%s'", argv[optind]);
+        return -EINVAL;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_bus_unref_ sd_bus *bus = NULL;
+        int r;
+
+        log_parse_environment();
+        log_open();
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                goto finish;
+
+        if (arg_address) {
+                r = sd_bus_new(&bus);
+                if (r < 0) {
+                        log_error("Failed to allocate bus: %s", strerror(-r));
+                        goto finish;
+                }
+
+                r = sd_bus_set_address(bus, arg_address);
+                if (r < 0) {
+                        log_error("Failed to set address: %s", strerror(-r));
+                        goto finish;
+                }
+
+                r = sd_bus_set_bus_client(bus, true);
+                if (r < 0) {
+                        log_error("Failed to set bus client: %s", strerror(-r));
+                        goto finish;
+                }
+
+                r = sd_bus_start(bus);
+        } else if (arg_user)
+                r = sd_bus_open_user(&bus);
+        else
+                r = sd_bus_open_system(&bus);
+
+        if (r < 0) {
+                log_error("Failed to connect to bus: %s", strerror(-r));
+                goto finish;
+        }
+
+        r = busctl_main(bus, argc, argv);
+
+finish:
+        pager_close();
+        strv_free(arg_matches);
 
-fail:
         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }