From 702d74b62a65e46f083172d4454ad9ebf10b5e0d Mon Sep 17 00:00:00 2001 From: Luca Boccassi Date: Wed, 7 Aug 2024 21:59:26 +0100 Subject: [PATCH] busctl: add --num-matches= for monitor verb Useful in scripts when one wants to wait for a specific signal before continuing --- man/busctl.xml | 13 +++++++++++++ shell-completion/bash/busctl | 2 +- shell-completion/zsh/_busctl | 1 + src/busctl/busctl.c | 20 ++++++++++++++++++++ test/units/TEST-74-AUX-UTILS.busctl.sh | 2 +- 5 files changed, 36 insertions(+), 2 deletions(-) diff --git a/man/busctl.xml b/man/busctl.xml index 0938582c8bd..c313d29955a 100644 --- a/man/busctl.xml +++ b/man/busctl.xml @@ -406,6 +406,19 @@ + + + + + When used with the monitor command, if enabled will make + busctl exit when the specified number of messages have been received and + printed. This is useful in combination with , to wait for the specified + number of occurrences of specific D-Bus messages. + + + + + diff --git a/shell-completion/bash/busctl b/shell-completion/bash/busctl index bb80c176830..ea88cca8c6e 100644 --- a/shell-completion/bash/busctl +++ b/shell-completion/bash/busctl @@ -89,7 +89,7 @@ _busctl() { --allow-interactive-authorization=no --augment-creds=no --watch-bind=yes -j -l --full --xml-interface' [ARG]='--address -H --host -M --machine --match --timeout --size --json - --destination' + --destination --num-matches' ) if __contains_word "--user" ${COMP_WORDS[*]}; then diff --git a/shell-completion/zsh/_busctl b/shell-completion/zsh/_busctl index c8c4f96ed16..0018cf66223 100644 --- a/shell-completion/zsh/_busctl +++ b/shell-completion/zsh/_busctl @@ -284,4 +284,5 @@ _arguments \ '--allow-interactive-authorization=[Allow interactive authorization for operation]:boolean:(1 0)' \ '--timeout=[Maximum time to wait for method call completion and monitoring]:timeout (seconds)' \ '--augment-creds=[Extend credential data with data read from /proc/$PID]:boolean:(1 0)' \ + '--num-matches=[Exit after receiving a number of matches while monitoring]:integer' \ '*::busctl command:_busctl_commands' diff --git a/src/busctl/busctl.c b/src/busctl/busctl.c index 31104f36c59..3735337a800 100644 --- a/src/busctl/busctl.c +++ b/src/busctl/busctl.c @@ -63,6 +63,7 @@ static bool arg_augment_creds = true; static bool arg_watch_bind = false; static usec_t arg_timeout = 0; static const char *arg_destination = NULL; +static uint64_t arg_num_matches = UINT64_MAX; STATIC_DESTRUCTOR_REGISTER(arg_matches, strv_freep); @@ -1361,6 +1362,12 @@ static int monitor(int argc, char **argv, int (*dump)(sd_bus_message *m, FILE *f dump(m, stdout); fflush(stdout); + if (arg_num_matches != UINT64_MAX && --arg_num_matches == 0) { + if (!arg_quiet && arg_json_format_flags == SD_JSON_FORMAT_OFF) + log_info("Received requested number of matching messages, exiting."); + return 0; + } + if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected") > 0) { if (!arg_quiet && arg_json_format_flags == SD_JSON_FORMAT_OFF) log_info("Connection terminated, exiting."); @@ -2361,6 +2368,8 @@ static int help(void) { " --watch-bind=BOOL Wait for bus AF_UNIX socket to be bound in the file\n" " system\n" " --destination=SERVICE Destination service of a signal\n" + " --num-matches=NUMBER Exit after receiving a number of matches while\n" + " monitoring\n" "\nSee the %s for details.\n", program_invocation_short_name, ansi_highlight(), @@ -2400,6 +2409,7 @@ static int parse_argv(int argc, char *argv[]) { ARG_WATCH_BIND, ARG_JSON, ARG_DESTINATION, + ARG_NUM_MATCHES, }; static const struct option options[] = { @@ -2432,6 +2442,7 @@ static int parse_argv(int argc, char *argv[]) { { "watch-bind", required_argument, NULL, ARG_WATCH_BIND }, { "json", required_argument, NULL, ARG_JSON }, { "destination", required_argument, NULL, ARG_DESTINATION }, + { "num-matches", required_argument, NULL, ARG_NUM_MATCHES }, {}, }; @@ -2600,6 +2611,15 @@ static int parse_argv(int argc, char *argv[]) { arg_destination = optarg; break; + case ARG_NUM_MATCHES: + r = safe_atou64(optarg, &arg_num_matches); + if (r < 0) + return log_error_errno(r, "Failed to parse --num-matches= parameter '%s': %m", optarg); + if (arg_num_matches == 0) + return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "--num-matches= parameter cannot be 0"); + + break; + case '?': return -EINVAL; diff --git a/test/units/TEST-74-AUX-UTILS.busctl.sh b/test/units/TEST-74-AUX-UTILS.busctl.sh index 6e997b46c64..3ef94e5cb9f 100755 --- a/test/units/TEST-74-AUX-UTILS.busctl.sh +++ b/test/units/TEST-74-AUX-UTILS.busctl.sh @@ -109,4 +109,4 @@ busctl get-property -j \ (! busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager \ KExecWatchdogUSec t "foo") -busctl --quiet --timeout 1 --match "interface=org.freedesktop.systemd1.Manager" monitor >/dev/null +busctl --quiet --timeout 1 --num-matches 1 --match "interface=org.freedesktop.systemd1.Manager" monitor >/dev/null