machine: revert type change of "leader" in io.systemd.Machine.Register method

The varlink method io.systemd.Machine.Register() is in v256, hence type
of "leader" cannot be changed.
Let's revert the change by 755cb018c9b3e93245afb86ec94223756ddd70e4, and
introduce another field "leaderProcessId", which takes detailed information
of the process.

Fixes a regression caused by 755cb018c9b3e93245afb86ec94223756ddd70e4.
Fixes #36155.

diff --git a/src/machine/machine-varlink.c b/src/machine/machine-varlink.c
index a5240ddccf0be47d3b60918b479067505dee7928..56dc0728d6ae9b02e7d22a95de187c72fd5c474b 100644 (file)
--- a/src/machine/machine-varlink.c
+++ b/src/machine/machine-varlink.c
@@ -59,6 +59,10 @@ static int machine_leader(const char *name, sd_json_variant *variant, sd_json_di
         if (temp.pid == 1) /* refuse PID 1 */
                 return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not a valid leader PID.", strna(name));
 
+        /* When both leader and leaderProcessId are specified, they must be consistent with each other. */
+        if (pidref_is_set(leader) && !pidref_equal(leader, &temp))
+                return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' conflicts with already dispatched leader PID.", strna(name));
+
         pidref_done(leader);
         *leader = TAKE_PIDREF(temp);
 
@@ -130,6 +134,7 @@ int vl_method_register(sd_varlink *link, sd_json_variant *parameters, sd_varlink
                 { "service",           SD_JSON_VARIANT_STRING,        sd_json_dispatch_string,  offsetof(Machine, service),              0                 },
                 { "class",             SD_JSON_VARIANT_STRING,        dispatch_machine_class,   offsetof(Machine, class),                SD_JSON_MANDATORY },
                 { "leader",            _SD_JSON_VARIANT_TYPE_INVALID, machine_leader,           offsetof(Machine, leader),               SD_JSON_STRICT    },
+                { "leaderProcessId",   SD_JSON_VARIANT_OBJECT,        machine_leader,           offsetof(Machine, leader),               SD_JSON_STRICT    },
                 { "rootDirectory",     SD_JSON_VARIANT_STRING,        json_dispatch_path,       offsetof(Machine, root_directory),       0                 },
                 { "ifIndices",         SD_JSON_VARIANT_ARRAY,         machine_ifindices,        0,                                       0                 },
                 { "vSockCid",          _SD_JSON_VARIANT_TYPE_INVALID, machine_cid,              offsetof(Machine, vsock_cid),            0                 },

diff --git a/src/shared/varlink-io.systemd.Machine.c b/src/shared/varlink-io.systemd.Machine.c
index 1d6cab8da7766bfaf0cca717d55acf7a961f7e9a..b80cbc65d0257c2ad3d32a0ae0df9d4a35de1ced 100644 (file)
--- a/src/shared/varlink-io.systemd.Machine.c
+++ b/src/shared/varlink-io.systemd.Machine.c
@@ -30,18 +30,21 @@ static SD_VARLINK_DEFINE_STRUCT_TYPE(
 
 static SD_VARLINK_DEFINE_METHOD(
                 Register,
-                SD_VARLINK_DEFINE_INPUT(name,              SD_VARLINK_STRING, 0),
-                SD_VARLINK_DEFINE_INPUT(id,                SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
-                SD_VARLINK_DEFINE_INPUT(service,           SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
-                SD_VARLINK_DEFINE_INPUT(class,             SD_VARLINK_STRING, 0),
-                SD_VARLINK_DEFINE_INPUT_BY_TYPE(leader,    ProcessId,         SD_VARLINK_NULLABLE),
-                SD_VARLINK_DEFINE_INPUT(rootDirectory,     SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
-                SD_VARLINK_DEFINE_INPUT(ifIndices,         SD_VARLINK_INT,    SD_VARLINK_ARRAY|SD_VARLINK_NULLABLE),
-                SD_VARLINK_DEFINE_INPUT(vSockCid,          SD_VARLINK_INT,    SD_VARLINK_NULLABLE),
-                SD_VARLINK_DEFINE_INPUT(sshAddress,        SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
-                SD_VARLINK_DEFINE_INPUT(sshPrivateKeyPath, SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(name,                    SD_VARLINK_STRING, 0),
+                SD_VARLINK_DEFINE_INPUT(id,                      SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(service,                 SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(class,                   SD_VARLINK_STRING, 0),
+                SD_VARLINK_FIELD_COMMENT("The leader PID as simple positive integer."),
+                SD_VARLINK_DEFINE_INPUT(leader,                  SD_VARLINK_INT,    SD_VARLINK_NULLABLE),
+                SD_VARLINK_FIELD_COMMENT("The leader PID as ProcessId structure. If both the leader and leaderProcessId parameters are specified they must reference the same process. Typically one would only specify one or the other however. It's generally recommended to specify leaderProcessId as it references a process in a robust way without risk of identifier recycling."),
+                SD_VARLINK_DEFINE_INPUT_BY_TYPE(leaderProcessId, ProcessId,         SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(rootDirectory,           SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(ifIndices,               SD_VARLINK_INT,    SD_VARLINK_ARRAY|SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(vSockCid,                SD_VARLINK_INT,    SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(sshAddress,              SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(sshPrivateKeyPath,       SD_VARLINK_STRING, SD_VARLINK_NULLABLE),
                 SD_VARLINK_FIELD_COMMENT("Controls whether to allocate a scope unit for the machine to register. If false, the client already took care of that and registered a service/scope specific to the machine."),
-                SD_VARLINK_DEFINE_INPUT(allocateUnit,      SD_VARLINK_BOOL,   SD_VARLINK_NULLABLE),
+                SD_VARLINK_DEFINE_INPUT(allocateUnit,            SD_VARLINK_BOOL,   SD_VARLINK_NULLABLE),
                 VARLINK_DEFINE_POLKIT_INPUT);
 
 static SD_VARLINK_DEFINE_METHOD(