From: Mike Yuan <me@yhndnzj.com>
Date: Sat, 24 Feb 2024 01:39:32 +0000 (+0800)
Subject: systemctl-show: use lookup_unit_by_pidref too
X-Git-Tag: v256-rc1~746^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=d95705cc883bf18eccc9f7ed31c25a9bb9e33850;p=thirdparty%2Fsystemd.git

systemctl-show: use lookup_unit_by_pidref too

Follow-up for e0e7bc8223c3f28fcb48db9f0f003d9f03ca46d7

This allows us to pin the process locally when GetUnitByPIDFD
is not available, just like what we have been doing for
'systemctl whoami'. Also, fix looking up remote pid.
We can't use pidfd for those.
---

diff --git a/src/systemctl/systemctl-show.c b/src/systemctl/systemctl-show.c
index 999e08b16e8..7926bfbecaf 100644
--- a/src/systemctl/systemctl-show.c
+++ b/src/systemctl/systemctl-show.c
@@ -2200,96 +2200,6 @@ static int show_one(
         return 0;
 }
 
-static int get_unit_dbus_path_by_pid_fallback(
-                sd_bus *bus,
-                uint32_t pid,
-                char **ret_path,
-                char **ret_unit) {
-
-        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
-        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
-        _cleanup_free_ char *path = NULL, *unit = NULL;
-        char *p;
-        int r;
-
-        assert(bus);
-        assert(ret_path);
-        assert(ret_unit);
-
-        r = bus_call_method(bus, bus_systemd_mgr, "GetUnitByPID", &error, &reply, "u", pid);
-        if (r < 0)
-                return log_error_errno(r, "Failed to get unit for PID %"PRIu32": %s", pid, bus_error_message(&error, r));
-
-        r = sd_bus_message_read(reply, "o", &p);
-        if (r < 0)
-                return bus_log_parse_error(r);
-
-        path = strdup(p);
-        if (!path)
-                return log_oom();
-
-        r = unit_name_from_dbus_path(path, &unit);
-        if (r < 0)
-                return log_oom();
-
-        *ret_unit = TAKE_PTR(unit);
-        *ret_path = TAKE_PTR(path);
-
-        return 0;
-}
-
-static int get_unit_dbus_path_by_pid(
-                sd_bus *bus,
-                uint32_t pid,
-                char **ret_path,
-                char **ret_unit) {
-
-        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
-        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
-        _cleanup_free_ char *path = NULL, *unit = NULL;
-        _cleanup_close_ int pidfd = -EBADF;
-        char *p, *u;
-        int r;
-
-        assert(bus);
-        assert(ret_path);
-        assert(ret_unit);
-
-        /* First, try to send a PIDFD across the wire, so that we can pin the process and there's no race
-         * condition possible while we wait for the D-Bus reply. If we either don't have PIDFD support in
-         * the kernel or the new D-Bus method is not available, then fallback to the older method that
-         * sends the numeric PID. */
-
-        pidfd = pidfd_open(pid, 0);
-        if (pidfd < 0 && ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
-                return get_unit_dbus_path_by_pid_fallback(bus, pid, ret_path, ret_unit);
-        if (pidfd < 0)
-                return log_error_errno(errno, "Failed to open PID %"PRIu32": %m", pid);
-
-        r = bus_call_method(bus, bus_systemd_mgr, "GetUnitByPIDFD", &error, &reply, "h", pidfd);
-        if (r < 0 && sd_bus_error_has_name(&error, SD_BUS_ERROR_UNKNOWN_METHOD))
-                return get_unit_dbus_path_by_pid_fallback(bus, pid, ret_path, ret_unit);
-        if (r < 0)
-                return log_error_errno(r, "Failed to get unit for PID %"PRIu32": %s", pid, bus_error_message(&error, r));
-
-        r = sd_bus_message_read(reply, "os", &p, &u);
-        if (r < 0)
-                return bus_log_parse_error(r);
-
-        path = strdup(p);
-        if (!path)
-                return log_oom();
-
-        unit = strdup(u);
-        if (!unit)
-                return log_oom();
-
-        *ret_unit = TAKE_PTR(unit);
-        *ret_path = TAKE_PTR(path);
-
-        return 0;
-}
-
 static int show_all(
                 sd_bus *bus,
                 SystemctlShowMode show_mode,
@@ -2461,9 +2371,9 @@ int verb_show(int argc, char *argv[], void *userdata) {
 
                         } else {
                                 /* Interpret as PID */
-                                r = get_unit_dbus_path_by_pid(bus, id, &path, &unit);
+                                r = lookup_unit_by_pidref(bus, (pid_t) id, &unit, &path);
                                 if (r < 0) {
-                                        ret = r;
+                                        RET_GATHER(ret, r);
                                         continue;
                                 }
                         }